Search

International audience; This paper describes the contribution of the closed-loop control of the motion platform (six degrees of freedom: longitudinal, lateral, and vertical displacements; pitch, roll, yaw) and motion platform’s three-dimensional (3D) displacement scale factor (SF) (0.2 and 1.0) on eye pupil diameter (PD) as an objective measure of driver cognitive load. Longitudinal, lateral, and vertical accelerations as well as longitudinal, lateral, and vertical positions from the center of gravity (CG) of the vehicle were registered through the driving simulation software SCANeRstudio® from OKTAL. Closed-loop control decreases the driver mental load. This type of closed-loop control can be used to decrease the driver mental load.

It has been predicted that the prevailing COVID-19 situation would result in increased demand for personal vehicles. There is a renewed interest in the 3 wheeled vehicles for short urban mobility in western countries due to their inherent cost advantages which will make it affordable for the common man. As the world is moving towards electric vehicle technology, a light 3 wheeled vehicle option will also help in reducing battery weight and thereby help in addressing the range concerns. In addition, slow speed 3-wheelers need not pass extensive safety regulation tests in many western countries including the USA. Three-wheeled vehicles are not new to developing countries like India as three-wheeled auto-rickshaws are quite popular for short distance shared travel. The existing single front wheel design known as delta design may have a stigma attached to it due to historic reasons in India. There is also a perception that the three-wheeled vehicles are highly unstable. Therefore, the current paper studies in detail an alternate design known as the tadpole design having two wheels in the front. The tadpole configuration facilitates decent styling and good aerodynamics. The tadpole configuration is modeled and analyzed using CAE multibody dynamics software, MSC Adams Car. To get confidence in the simulation results, a few benchmarked and tested vehicles are selected from the available literature [1] and the MBD results are compared for correlation. The studies also include a standard four-wheeled vehicle and a delta configuration 3-wheeler for reference purpose. The MBD virtual analyses provide results for vehicle stability and handling characteristics like overturning speed limit, oversteer and understeer behavior during constant radius cornering tests. The paper, by keeping in mind the typical urban driving condition and pattern, gives its feedback and recommendation about the tadpole configured 3-wheeler. © 2021 SAE International. All rights reserved.

Object trackers are a tool to achieve accurate object state estimation over time. Due to their complexity, a framework to experiment with different variations of trackers and their subcomponents is desired. This drove the authors research and experimentation with object tracking using MathWorks toolsets. In this paper, three object trackers - Point Target Tracker (PTT), Gamma Gaussian Inverse Wishart Probability Hypothesis Density (GGIW-PHD), and Gaussian Mixture Probability Hypothesis Density (GM-PHD) - are compared in simulation for track statistics and object/track accuracy. The results show that a rectangular GM-PHD multi object tracker outperforms the other trackers. A follow up is shown using real-world data and the process used to get the sensor data into the appropriate MathWorks format. The impact of COVID-19 prevented the collection of ground truth data so the real-world data cannot be compared using the same metrics. For this reason, the simulation portion of this paper will act as the detailed discussion of fusion and tracking while the real-world testing portion is an overview of the authors' process of converting real-world sensor data into a format compatible with MathWorks object tracking tools. © 2021 SAE International. All rights reserved.

In today's era of rapid globalization and high consumer demand the automotive industry faces a major challenge to meet the growing demands for customized products, which suits the branding strategy, customer needs and industry trends. Modular approach to product development not only helps in reducing the product development time, but it also supports the automotive industry to customize the needs of consumers in an effective manner, create unique brand identity and reduce development cost. Product platform modularization is a great opportunity for the original equipment manufacturers (OEM's) to develop platform strategies across multiple brands and the ability to customize products. During current pandemic times with COVID-19, automotive manufactures will need to rethink their product strategies and focus on the platform mindset to deliver products that meet consumer demands. The paper provides a novel approach in developing modular platform solutions by defining guidelines for "Common"and "Unique"modules linked with critical interfaces. It also provides ways to keep "Brand"uniqueness by maintaining modularity with the systems. A theoretical process is described in the paper with few examples to illustrate the modular approach and branding strategy. The paper also provides a basic approach for all vehicle types to allow manufacturers to focus their efforts on areas where there is high degree of modularity and commonality using the branding strategy. © 2021 SAE International. All Rights Reserved.

This paper was commissioned for the design and analysis of an entire rear suspension system befitting a Formula Society of Automotive Engineers (FSAE) vehicle. The paper includes a literature review to gain a full understanding of the workings and design decisions applied to the rear suspension in the Society of Automotive Engineers (SAE) competition. After completing the design development process, a final analysis of the designed system was done to ensure the minimum two years-of-life requirement is met. It was found that due to constraints, a major design change was necessary that involves mounting the A-arms further forward on the chassis body than previous generation vehicles. This design increased the stresses present in the system compared to previous designs. As such, careful consid-eration had been given to the analysis aspect of the paper. Full fatigue analysis performed individually on each component proved that the lower A-arm was the most critical component, with a predicted failure at 1466 laps. However, with the given lifespan of two years, this design procured a conservative Factor of Safety of above two years.Notable mention should be given to the complete develop-ment of an FSAE uniaxial force determination code that was produced by Team Recoil. This code greatly improved the confidence in component forces and thus allowed less conservative design choices in several other aspects.

The automotive trends of vehicles with lower aerodynamic drag and more powerful drivetrains have caused increasing concern regarding stability issues at high speeds, since more streamlined bodies show greater sensitivity to crosswinds. This is especially pronounced for high vehicles, such as sports utility vehicles. Besides, the competitiveness in the automotive industry requires faster development times and, thus, a need to evaluate the high speed stability performance in an early design phase, preferable using simulation tools. The usefulness of these simulation tools partly relies on realistic boundary conditions for the wind and quantitative measures for assessing stability without the subjective evaluation of experienced drivers. This study employs an on-road experimental measurements setup to define relevant wind conditions and to find an objective methodology to evaluate high speed stability. The paper focuses on the events in proximity to the drivers’ subjective triggers of instability. Wind direction and magnitude, vehicle motion response, along with the subjective event triggering were measured at different conditions of the natural wind. A statistical approach was utilized to analyze the correlation between the vehicle response and subjective triggers together with the wind conditions. A correlation was established between the subjective triggers and a rapid change in lateral acceleration and yaw velocity response. The paper also proposes a set of four crosswind gust profiles of interest for driving stability, combining results from previous research and the experimental data of the natural wind obtained in this study. These findings can be used as objective measures for virtually assessing stability performance and as realistic boundary conditions for simulating wind gusts.

Development processes for modern combustion engines already make substantial use of more or less sophisticated simulation approaches. The enhancement of computational resources additionally allows the increasing use of simulation tools in terms of time-consuming three-dimensional CFD approaches. In particular, the preliminary estimation of feasible operating ranges and strategies requires a vast multitude of single simulations. Here, multi-zone simulation approaches incorporate the advantages of comparably short simulation durations. Nevertheless, the combination with more detailed sub-models allows these rather simple modeling approaches to offer considerable insight into relevant engine operation phenomena. In the context of combustion process development, this paper describes a phenomenological model approach for the prediction of operating point characteristics of a dual-fuel pilot injection combustion process. In order to describe the ignition initiated by pilot fuel injection, the present model approach uses the package-based multi-zone approach as presented by Hiroyasu et al. Therefore, physical phenomena such as spray breakup, atomization, and evaporation are considered. The governing entrainment of premixed cylinder charge into the individual package zones is based on the conservation of momentum. In addition, measured pilot fuel injection profiles are implemented. The calculation of the characteristic ignition delay time applies an Arrhenius-based one-step mechanism taking local gas properties as well as the particular composition within the packages into account. Eventually, the identification of the ignition event triggers a transition process from the combustion within the spray cone to the hemispherical flame propagation of the premixed cylinder filling. Besides the detailed description of the model approach, this paper discusses crucial influences originating from quasi-dimensional discretization. In particular, the radial discretization of the spray jet indicates a considerable influence on the prediction of spray breakup as well as fresh gas mixing into the package zones and thus eventually on the calculation of the ignition delay time. The validation of the phenomenological model approach regarding its ability to predict different operating characteristics uses experimental data. Here, variations of timing and the quantity of the pilot fuel injection as well as variations of injection pressure and global air-fuel equivalence ratio have been taken into account. The model approach indicates plausible prediction with regard to both the basic phenomenology of the combustion process and the characteristic two-stage ignition behavior. In particular, cylinder pressure curves and combustion rates as well as peak pressures and the overall released heat quantities are correctly calculated.

A major challenge in automotive NVH engineering is to approach complex structure-borne sound and vibration problems with sufficient accuracy but reasonable experimental effort. Typical issues encountered are poor correlation between objective component performance criteria tested for during bench validation and corresponding subjective targets evaluated during system validation in the actual vehicle. Additional challenges arise from the need to impose assumptions on sophisticated physical vibration problems to reduce the complexity to a level feasible for conventional experimental test methods. This paper addresses all mentioned issues by elaborating on a system NVH engineering approach employing Virtual Acoustic Prototyping (VAP) (related to what is now often called component Transfer Path Analysis) to synthesize time domain sound and vibration responses of vibrating machinery operated in a virtual vehicle environment. One crucial step of VAP is to characterize the strength of vibrating machinery by independent quantities at the significant coupling degrees of freedom (DoF). This study puts special focus on the measurement of free velocity, suitable for machinery operated when resiliently mounted as per ISO 9611, and the in-situ measurement of blocked forces, applicable for sources connected to any type of receiving structure during operation, as per ISO/DIS 20270. In order to reduce complexity of the underlying measurements this paper investigates the possibility of using collocated sensor arrays and methods to validate assumptions imposed to abstract away from rotational coupling DoF. An electric power steering (EPS) system inducing vibrations into a sub-frame-type structure is considered as a representative automotive source-receiver installation to investigate the feasibility of free velocity and in-situ blocked force approach with respect to independent source characterization for component Transfer Path Analysis (TPA) and VAP. The obtained Virtual Acoustic Prototype is expanded using an algorithm to synthesize realistic time domain data, enabling NVH engineers to conduct reliable objective and subjective design evaluations.

This paper presents a methodology used to configure an electric drive system for a Formula Student car and the detailed design of a transmission for in-hub motor placement. Various options for the size, number and placement of electric motors were considered and a systematic process was undertaken to determine the optimum configuration and type of motor required. The final configuration selected had four 38 kW in-hub motors connected through a 14.8:1 reduction transmission to 10” wheels. Preliminary design of the transmission design indicated that the overall gear ratio would be best achieved with a two-stage reduction, and in this work an offset primary spur stage coupled to a planetary second stage was chosen. Detailed design and validation of the transmission was conducted in Ricardo SABR and GEAR, using a duty cycle derived from an existing internal combustion Formula Student car. The analysis was conducted in line with ISO 6336 and permitted the examination of the stresses in gear teeth and the prediction of gear and bearing life. A detailed design was proposed with due regard to ease of manufacture and assembly, and a full-scale prototype was manufactured to facilitate physical validation of the design. The design analysis showed all gears and bearings had a suitable predicted lifetime with a minimum factor of safety of 1.8 on gear wear.

© 2019 SAE International. All Rights Reserved. Evolvable Assembly Systems is a five year UK research council funded project into flexible and reconfigurable manufacturing systems. The principal goal of the research programme has been to define and validate the vision and support architecture, theoretical models, methods and algorithms for Evolvable Assembly Systems as a new platform for open, adaptable, context-aware and cost effective production. The project is now coming to a close; the concepts developed during the project have been implemented on a variety of demonstrators across a number of manufacturing domains including automotive and aerospace assembly. This paper will show the progression of demonstrators and applications as they increase in complexity, specifically focussing on the Future Automated Aerospace Assembly Phase 1 technology demonstrator (FA3D). The FA3D Phase 1 demonstrated automated assembly of aerospace products using precision robotic processes in conjunction with low-cost reconfigurable fixturing supported by large volume metrology. This was underpinned by novel agent-based control for transformable batch-size-of-one production. The paper will conclude by introducing Phase 2 of the Future Automated Aerospace Assembly Demonstrator - currently in development - that will translate the Evolvable Assembly Systems research to a higher technology readiness level and address the challenges of scalable and transformable manufacturing systems.

The paper deals with experimental testing of a natural gas fueled engine. Break Specific fuel Consumption (BSFC), Average Mass Flow Rate, Instantaneous Cylinder Pressure and some wall temperatures have been measured at some full and part load operating conditions. The results of this experimental activity, still in progress, have been used to calibrate a 1D-flow engine’s model. Then the effects of some VVA strategies have been theoretically studied through the validated model. With the aim of maximizing the full load engine’s torque, a genetic algorithm was used to calculate the optimized intake and exhaust valves timing angles. Various VVA strategies were compared at part-load in order to reduce brake specific fuel consumption.

Due to stricter emission regulations and more environmental awareness, the powertrain systems are moving toward higher fuel efficiency and lower emissions. In response to these pressing needs, new technologies have been designed and implemented by manufacturers. As a result of increasing complexity of the powertrain systems, their control and optimization become more and more challenging. Virtual powertrain calibration, also known as model-based calibration, has been introduced to transfer a part of test bench testing into a virtual environment, and hence considerably reduce time and cost of product development process while increasing the product quality. Nevertheless, virtual calibration has not yet reached its full potential in industrial applications. Volvo Penta has recently developed a virtual test cell named VIRTEC, which is used in an ongoing pilot project to meet the Stage V emission standards. The integrated powertrain system includes engine, Exhaust Aftertreatment System (EATS), and Engine Management System (EMS). The objective of this paper is to describe the essential aspects required to increase the contribution of virtual testing in powertrain calibration activities. These aspects comprise the following: Hardware-in-the-Loop (HiL) system, simulation models, and working process for joint virtual and physical testing to facilitate efficient powertrain development process. The current paper describes the design, test and verification of a calibration platform based on the requirements of the project. The future phases in the current project (Virtual Calibration at Volvo Penta) will cover validation of the platform by performing calibrations in industrial scales on the virtual system.

One dimensional (1D) and three dimensional (3D) simulations are widely used in technical acoustics to predict the behavior of duct system elements including fluid machines. In particular, referring to internal combustion engines, the numerical approaches can be used to estimate the Transmission Loss (TL) of mufflers, air boxes, catalytic converters, etc. TL is a parameter commonly used in almost any kind of acoustical filters, in order to assess the passive effects related to their sound attenuation. In this paper, a previous 1D-3D acoustical analysis of a commercial muffler, has been improved and experimentally validated. Features related to the manufacturing process, like the coupling of adjacent surfaces and the actual shape of components, have been noticed to heavily affect the muffler behavior. Hence, although numerical analyses are usually performed on ideal geometries (perfectly matched and shaped), schematizations utilized for acoustic simulations of real mufflers are being suggested to do not neglect these important aspects. On the other hand, for a given initial muffler design, the manufacturing process is assessed to be a critical aspect also for its remarkable effects on the acoustics. In this work, results have been carried out under different muffler operating conditions related to different mean flow velocities and presence or not of internal insulating material. 1D analyses have been performed by implementing a commercial software, solving the nonlinear flow equations which characterize the wave propagation phenomena. 1D approach has also been utilized to evaluate the fluid dynamic behavior of the studied muffler in terms of pressure drop when a mean flow is imposed. 3D results are obtained in absence of mean flow by using a commercial software based on Boundary Element approach and solving the three dimensional Helmholtz's equation. Finally, during the experimental tests, the muffler has been treated as an acoustic two-port element.

The major contribution of this paper is to propose a low-cost accurate distance estimation approach. It can potentially be used in driver modelling, accident avoidance and autonomous driving. Based on MATLAB and Python, sensory data from a Continental radar and a monocular dashcam were fused using a Kalman filter. Both sensors were mounted on a Volkswagen Sharan, performing repeated driving on a same route. The established system consists of three components, radar data processing, camera data processing and data fusion using Kalman filter. For radar data processing, raw radar measurements were directly collected from a data logger and analyzed using a Python program. Valid data were extracted and time stamped for further use. Meanwhile, a Nextbase monocular dashcam was used to record corresponding traffic scenarios. In order to measure headway distance from these videos, object depicting the leading vehicle was first located in each frame. Afterwards, the corresponding vanishing point was also detected and used to automatically compute the camera posture, which is to minimize the interference caused by camera vibration. The headway distance can hence be obtained by assuming the leading and host vehicles were in the same ground plane. After both sensory data were obtained, they were synthesized and fused using Kalman filter, to generate a better estimation of headway distance. The performances of both sensors were assessed individually and the correlation between their measurements was evaluated by replotting radar measurements on the video stream. The results of individual sensors and Kalman filter were compared to investigate the optimization performance of the data fusion approach.This is a general guidance of headway distance estimation with a low cost radar and a monocular camera. With described general procedures, this paper can allow researchers to easily fuse radar and camera measurements to obtain optimized headway distance estimation. This paper can facilitate the development of a more realistic robotic driver that can mimic human driver behaviors.

The emergence of wide band gap devices has pushed the boundaries of power converter operations and high power density applications. It is desirable to operate a power inverter at high switching frequencies to reduce passive filter weight and at high temperature to reduce the cooling system requirement. The paper describes the design and test of a power electronic inverter that converts a fixed input DC voltage to a variable voltage variable frequency three phase output. The component selection and design were constrained such that the inverter can operate at an ambient temperature of 170°C. The design of the key functional components such as the gate drive, power module, controller and communication will be discussed in the paper. Test results for the inverter at high temperature will also be presented.

The current paper is based on the French research program TESSA (“Transfert des Efforts des Sources Solidiennes Actives”). A specific task within TESSA project consists in the characterization of the measurements variability between several laboratories, of the blocked forces on a water pump of a heat engine. This paper focuses only on the measurements carried out at Vibratec laboratory. Two kinds of measurements have been carried out: direct measurements, using force sensors, which is the target of the inter-laboratory measurements, and an inverse method without force sensor requirements. Reproducibility and repeatability tests have been done in order to quantify the measurement variability within the same laboratory, in preparation for the inter-laboratory disparity analysis. Specific supports have been designed for each method: a rigid aluminum block for the direct method and a support dedicated to the inverse method, including a high modal density and modal damping in the frequency range of interest. The comparison of both methods shows that the inverse method is satisfying for the measurement of blocked forces on a “non-rigid” support and that it is possible to apply such methodology “in-situ”, with the source in its real environment. Mots clefs : Source solidienne, Effort de blocage, Methode inverse 22 Congres Francais de Mecanique Lyon, 24 au 28 Aout 2015

The paper is based upon work supported by Saudi Aramco Research and Development Center FUELCOM3 program under Master Research Agreement Number 6600024505/01. FUELCOM (Fuel Combustion for Advanced Engines) is a collaborative research undertaking between Saudi Aramco and KAUST intended to address the fundamental aspects of hydrocarbon fuel combustion in engines, and develop fuel/engine design tools suitable for advanced combustion modes. The computational simulations utilized the Shaheen supercomputer at KAUST Supercomputing Laboratory. The scientific visualization was supported by the KAUST Visualization Core Laboratory. The authors thank Convergent Science Inc. for providing the CONVERGE license.

Low Carbon fuels will play a relevant role in the transportation sector contributing, over the powertrain technology progress, to mitigate global CO2 emissions. Compressed Natural Gas (CNG), mainly composed by methane, is one of the best candidate thanks to its chemical composition and to its wide diffusion and use. Blending Hydrogen in Natural Gas could represent a further step for a better CO2 footprint (considering renewable or biohydrogen) but also to optimize the combustion process, increasing the engine thermal efficiency and reducing pollutant formation. On the other hand, capability to automatically adapt the engine parameters to variable concentrations of Hydrogen in Natural Gas (in the range from 0% to 40% by volume) is a mandatory step to maintain engine performance, emissions and efficiency The activities described in this paper are part of a large collaborative project, “Biomethair”, funded by Regione Piemonte, where material specifications on gas tanks, valves, feeding lines, gas pressure regulator, engine pipes and injectors have been set and prototype components procured and implemented into the demonstrator vehicle to ensure safe operating conditions. In this paper a software algorithm is presented, able to provide, during normal car operation, real time estimates of methane-hydrogen composition, allowing the engine control system to adapt the control parameters engine. The algorithm is based on the innovative data-driven technology Direct Virtual Sensor, which allows to design the Virtual Sensor from the experimental data collected from a testing car, subject to suitable manoeuvres in different operational conditions, without requiring deep first principle modelling of the involved systems. The Virtual Sensor has been designed and implemented on the Electronic Control Unit of the demonstrator vehicle, giving suitably discretized estimates of Methane-Hydrogen composition, using measurements of engine revolution speed, of the lambda probe value and a variable from engine control unit. Experimental results of the Virtual Sensor performance evaluated in different operational conditions are presented.

Today, LRI is a proven manufacturing technology for both small and large scale structures (e.g. sailboats) where, in most cases, experience and limited prototype experimentation is sufficient to get a satisfactory design. However, large scale aerospace (and other) structures require reproducible, high quality, defect free parts, with excellent mechanical performance. This requires precise control and knowledge of the preforming (draping and manufacture of the composite fabric preforms), their assembly and the resin infusion. The INFUCOMP project is a multi-disciplinary research project to develop necessary Computer Aided Engineering (CAE) tools for all stages of the LRI manufacturing process. An ambitious set of developments have been undertaken that build on existing capabilities of leading drape and infusion simulation codes available today. Currently the codes are only accurate for simple drape problems and infusion analysis of RTM parts using matched metal moulds. Furthermore, full chaining of the CAE solution will allow results from materials modelling, drape, assembly, infusion and final part mechanical performance to be used in subsequent analyses. Although the materials and manufacturing methods in INFUCOMP are specific to aerospace structures, it is expected that the work would be of great value to other industries, including energy (windmill), rail, sea, advanced automotive and manufacturing. INFUCOMP has built on PAM-RTM, an existing simulation software, to provide a full solution chain for LRI composites; including fabric modelling, drape, assembly, infusion, cost and final part performance prediction. Simulation tools will avoid costly and time consuming prototype testing, will allow the CAE design of alternative manufacturing routes and enable cost effective, efficient LRI composite structures to be designed and manufactured. This paper presents the work carried out during industrial validation phase of the project on simplified industrial components and an industrially relevant LRI aircraft sub-structure. This work has used several specific developments including numerous enhancements to the state-of-the-art for resin infusion simulation; in particular, better viscosity models and essential developments to run under DMP (Distributed Memory Processing) to take advantage of new generation cluster computers and massive parallel computing. Some details about coupling of modelling and monitoring allowing a combination of predictive capabilities provided by simulation with the capability of detecting unexpected events and variations in real time provided by process monitoring will be presented. Introduction Within the INFUCOMP project, an infusion-compression tool has been developed to fully simulate the infusion process, taking into account the deformations of the preform within PAM-RTM, an ESI Group software. Validations on small scale singularities that are representative of industrial issues have been conducted and are presented in this paper. After an initial description of the test and monitoring set-ups, we will present details of the simulations including input data and results. Finally, experiment results are compared with simulation results. Following those representative tests, an industrial benchmark will be detailed including defect prediction by simulation and correlation with experimental results.

1 Abstract This paper describes a modeling, simulation, and visualization framework aimed at enabling physicsbased analysis of ground vehicle mobility. This framework, called Chrono, has been built to leverage parallel computing both on distributed and shared memory architectures. Chrono is both modular and extensible. Modularity stems from the design decision to build vertical applications whose goal is to reduce the end-to-end time from vision-to-modelto-solution-to-visualization for a targeted application field. The extensibility is a consequence of the design of the foundation modules, which can be enhanced with new features that benefit all the vertical applications. Two factors motivated the development of Chrono. First, there is a manifest need of modeling approaches and simulation tools to support mobility analysis on deformable terrain. Second, the hardware available today has improved to a point where the amount of sheer computer power, the memory size, and the available software stack (productivity tools and programming languages) support computing on a scale that allows integrating highly accurate vehicle dynamics and physics-based terramechanics models. Although commercial software is available nowadays for simulating vehicle and tire models that operate on paved roads; deformable terrain models that complement the fidelity of present day vehicle and tire models have been lacking due to the complexity of soil behavior. This paper demonstrates Chrono’s ability to handle these difficult mobility situations through several simulations, including: (i) urban operations, (ii) muddy terrain operations, (iii) gravel slope operations, and (iv) river fording.

The bus sector is currently lagging behind when it comes to implementing autonomous systems for improved vehicle safety. However, in cities such as London, public transport strategies are changing, with requirements being made for advanced driver-assistance systems (ADAS) on buses. This study discusses the adoption of ADAS systems within the bus sector. A review of the on-road ADAS bus trials shows that passive forward collision warning (FCW) and intelligent speed assistance (ISA) systems have been successful in reducing the number of imminent pedestrian/vehicle collision events and improving speed limit compliance, respectively. Bus accident statistics for Great Britain have shown that pedestrians account for 82% of all fatalities, with three quarters occurring with frontal bus impacts. These statistics suggest that the bus forward collision warning system is a priority for inclusion in future vehicles to enhance the driver’s direct vision, and to increase reaction time for earlier brake application. Almost 80% of bus occupant casualties occurred in non-impact situations, mainly during acceleration/deceleration events. Therefore, care must be taken in implementing autonomous braking in buses, to ensure that it does not cause an increased number of deceleration events beyond the safe stability limits for passengers. Real on-road drive cycle data has shown that while instances of unsafe braking events do not occur regularly, there are instances of braking events that would present a hazard to both seated and standing passengers, therefore systems that would mitigate these issues would have real benefits to both passenger comfort and safety. During tests to simulate the use of the vehicle retarder for an autonomous braking system, deceleration rates largely remained safely within standee and seated passenger stability limits, whereas an emergency stop test showed a peak deceleration 3.5 times the limit of a standee supported by a vertical handrail, and 4 times the limit for a forward/backward facing seated passenger.

Classical decentralized architectures based on large networks of microprocessor-based Electronic Control Units (ECU), namely those used in self-driving cars and other highly-automated applications used in the automotive industry, are becoming more and more complex. These new, high computational power demand applications are constrained by limits on energy consumption, weight, and size of the embedded components. The adoption of new embedded centralized electrical/electronic (E/E) architectures based on dynamically reconfigurable hardware represents a new possibility to tackle these challenges. However, they also raise concerns and questions about their safety. Hence, an appropriate evaluation must be performed to guarantee that safety requirements resulting from an Automotive Safety Integrity Level (ASIL) according to the standard ISO 26262 are met. In this paper, a methodology for the evaluation of dynamically reconfigurable systems based on centralized architectures is presented. The aim is to evaluate the reliability and probability of failure while exploring the design space without compromise the overall system performance. The methodology is divided into three stages. In the first stage, the system is decomposed, and its sub-systems are isolated before applying a Fault Tree Analysis on the elements of each sub-system. The mathematical stochastic model of Markov Chain is used in the second stage to obtain the reliability function and the quantification of the Mean Time to Failure (MTTF) of the system. Finally, the overall system is evaluated in terms of performance, and according to time constraints such as reconfiguration latency in case of failure. Applying this method, we quantify the MTTF in Failure in Time (FIT) format of an E/E architecture. Additionally, we evaluate each sub-system independently and obtain the respective ASIL decomposition of the overall system. The aim is to evaluate the migration of safety-related functionalities/redundancy from traditional architectures into reprogrammable devices. With the application of this methodology, we can evaluate the reliability and performance of dynamically reconfigurable systems and define new E/E automotive architectures.

The various factors that affect ride comfort, including noise, vibrations and harshness (NVH) have been in focus in many research studies due to an increasing demand in ride comfort in the automotive industry. Vibrations have been highlighted as an important contribution to assess and predict overall ride comfort. The purpose of this paper is to present an approach to explain ride comfort with respect to vibration for the seated occupant based on a systematic literature review of previous fundamental research and to relate these results to the application in the contemporary automotive industry. The results from the literature study show that numerous research studies have determined how vibration frequency, magnitude, direction, duration affect human response to vibration. Also, the studies have highlighted how body posture, age, gender and anthropometry affect the human perception of comfort. An analysis was made of the consistency and inconsistency of the results obtained in the different studies. The deviations of the research results from real-world ride comfort in automotive vehicles were analyzed and divided into three groups: appreciable and consistent with industry results, appreciable and inconsistent with industry results and not appreciable in industrial results. The overall conclusion from this literature study was that there is much information available from laboratory studies regarding human response to vibrations, but there is a lack of studies that take into account all the different parameters that affect the overall ride comfort experience for automotive vehicle occupants.

This paper focuses on the modeling of rolling element bearings, a key component that is responsible of transmitting the vibrations from the gear pairs to the surrounding structure while introducing additional excitation frequencies. The modeling techniques use the relative displacement of the rings to compute the corresponding reaction forces by calculating the equilibrium of each rolling element. To do so, the interaction between the rolling elements and the raceways can be modeled employing two different contact models depending on the level of accuracy required. The contact models are, respectively, a Hertz-based approach that allows for fast computations, and an EHL (Elasto-Hydrodynamic Lubricated) contact model which accounts for the effects of lubrication. The procedure to calculate the equilibrium of the rolling elements allows for grasping the main effects, including centrifugal loads and misalignments. The presented approach is capable of correctly estimating the response of rolling element bearings on its 6-dof accounting for the coupling terms between different directions and to describe the load distribution over the rolling elements. These fast but accurate models for bearings are available in the portfolio of Siemens Digital Industry Software within the Simcenter 3D platform and complement the available advanced gear simulation technology recently released. To conclude, simulation results are carried out and validated against a full multibody model of a deep groove ball bearing created in Simcenter 3D Motion to assess the accuracy and the efficiency of the proposed technique.

Simscape is a physical modeling language developed by Mathworks Inc. The language uses equation statements instead of assignment statements to describe physical systems. The paper focuses on the Simscape language itself instead of using components in the Simscape libraries. The language will be introduced from a perspective different from the Mathworks’ Physical Network point of view. Our perspective focuses on two types of variables at the connectors. In additional, internal variables are not separated into through and across variables. The alternative perspective is more general and easier to understand. The paper also illustrates how to develop components in a powertrain library following the proposed new perspective. INTRODUCTION Physical object-oriented modeling approach greatly facilitates model development for complex multi-domain physical systems. In this approach, models for different components are developed independently and placed into libraries. A user can select components from the libraries and connect them together just like building a physical system. Connections between component models represent actual physical connections. The model layout mimics the physical system. Therefore, the model is much easier to understand, use, and maintain. The Simscape product family from Mathworks Inc. adds the physical modeling capability to Simulink. The basic package includes a foundation library and the Simscape modeling language. The foundation library contains basic components for mechanical, electrical and hydraulic systems, etc. There are also other specialized add-on libraries. The Simscape language [1] is a modeling language used to develop custom components. The Simscape language, like most physical modeling languages [2], uses equation statements instead of assignment statements. In equation statements, input and output variables are not explicitly specified, i.e., they are non-causal. The two sides of an equation statement are equal in a mathematical sense. The equations can be either differential or algebraic. A solver sorts and solves all equations through symbolic formula manipulation. This paper will focuses on the Simscape modeling language itself instead of on developing simulation models from existing libraries. The Simscape language will be introduced from a perspective different from the Mathworks’ Physical Network point of view. The physical Network approach centers on energy flows, which is not considered in our perspective. Our perspective only focuses on two types of variables at the connectors. Internal variables are not separated into through and across variables. We think this perspective is more general and easier to understand. The paper will first discuss the basics of the Simscape language from the new perspective. We will next introduce the powertrain library that was developed with the new perspective to validate the new perspective. The paper includes component models for two-flange rotational inertia, planetary gear set, and clutch. A complete transmission model and simulation results are also included.

The essential task of a battery management system (BMS) is to consistently operate the high-voltage battery in an optimum range. Due to the safety-critical nature of its components, prior testing of a BMS is absolutely necessary. Hardware-in-the-loop (HIL) simulation is a cost-effective and efficient tool for this. Testing the BMS on a HIL test bench requires an electronics unit to simulate the cell voltages and a scalable real-time battery model. This paper describes a HIL system that enables comprehensive testing of BMS components. Hardware and software solutions are proposed for the high requirements of these tests. The individual components are combined to make a modular system, and safety-critical aspects are examined. The paper shows that the system as developed fulfills all the requirements derived from the different test scenarios for BMS systems.

Model-based software development is increasingly being used to develop software for electronic control units (ECUs). When developing safety-related software, compared to nonsafety-related software development, additional requirements specified by relevant safety-standards have to be met. Meeting these requirements should also be considered to be best practices for non-safety-related software. This paper introduces a model-based reference workflow for the development of safety-related software conforming to relevant safety-standards such as IEC 61508 and ISO 26262. The reference workflow discusses requirements traceability aspects, software architecture considerations that help to support modular development and ease the verification of model parts and the code generated from those model parts, and the selection and enforcement of modeling and coding guidelines. Special focus is put on software unit and integration testing as an integral part of the overall verification and validation task. The presented methods and measures are mapped to the requirements of relevant functional safety-standards applied in the automotive industry. Furthermore the paper discusses the role of such a reference workflow for answering the ongoing question for software tool qualification. The new automotive safety-standard ISO 26262 introduces a new approach to adressing this topic. This approach is based on a new way of classifcation of the software tool based on the tools impact and the degree of confidence that a malfunction or erroneous output can be prevented or detected. SAFETY STANDARDS Standards that apply to automotive software development are IEC 61508 [1] and particularly new ISO 26262 [2]. IEC 61508 is a generic across-the-industries standard that encourages the derivation of industry-specific standards. It originated in the process control automation industry, and sector-specific standards have already been derived for the process industry (IEC 61511), nuclear power plants (IEC 61513) and machinery (IEC 61513). New ISO 26262, which reached ISO Draft International Standard (DIS) status in July 2009, is a derivative that is especially tailored to the automotive industry. Where IEC 61508 has to remain abstract in many points, ISO 26262 is far more specific with regard to automotive electronics development. IEC 61508 was created and published in the late 1990s, before model-based development and code generation became widely adopted. It can therefore give little direct advice of how to comply within a model-based development process. The standard has therefore to be interpreted. ISO 26262 AND MODEL-BASED DEVELOPMENT ISO 26262 addresses this issue and specifically covers model-based development aspects, reflecting the importance of this approach in automotive software development today. The ISO 26262 part relevant to model-based development is “Part 6: Product development: software level”. It contains a separate chapter in the annex that describes the concept of model-based development of in-vehicle software and outlines its implications on the product development at the software level. In this annex also differences between code-based and model-based development are pointed out. Furthermore there are several notes throughout ISO/DIS 26262-6 directly A Model-Based Reference Workflow for the Development of Safety-Related Software 2010-01-2338 Published 10/19/2010

This paper will present the latest development of a configurable and modular steel construction system for use in frameworks of flexible fixtures of the kind called Affordable Reconfigurable Fixtures (ART). Instead of a dedicated aircraft fixture, which is very time consuming and expensive, the ART fixtures enable affordable construction from a standard component kit, by solving the main draw-backs of traditional tooling. In early 2009 Airbus UK built the first steel modular fixture for the aerospace industry. The project was a partnership with DELFOi and Linkoping University in a project called ReFlex, Reconfigurable Flexible Tooling. A paper was presented in the last year SAE conference which explained about the project in overall. The construction system called BoxJoint has recently been tested in some manufacturing areas at Airbus UK and also been applied in the production at Saab Aerospace Linkoping Sweden. A case study was conducted of an A380 subassembly fixture demonstrating the comparable advantages of the new technology from the design phase until the first aircraft build. One of the benefits reported is that a modular fixture relatively quickly can be assembled and set within specified tolerances by means of a metrology system, guiding configurable pickups and flags called Flexapods. Calculation of strength and stiffness can be made by simple standard methods.

With the growing complexity of, and reliance on, safety-related electrical/electronic (E/E) systems in the automotive sector, the development of an explicit safety case is highly recommended to provide assurance to the different stakeholders interested in automotive functional safety. The production of a safety case is explicitly mandated by the draft automotive functional safety standard ISO26262. A safety case should consider all organisational and technical factors that may contribute to safety. For example, it should provide assurance for the safe behaviours of a particular system as well as assurance for the process by which this system is developed, operated and maintained. In this paper, we address one component of the overall safety case, namely the assurance of the functional safety concept. In particular, we examine how model-driven development and assessment can provide a basis for the systematic generation of functional safety requirements. We demonstrate how an automotive safety case can be structurally and traceably developed, justifying why and how the defined functional safety requirements can adequately mitigate the risk of the identified hazards to an acceptable level. A case study is also presented throughout this paper, discussing examples and lessons learnt from the development of a safety case for an air suspension system.

As automotive electronics become more complex and more distributed, hardware in-the-loop simulation is now a widely adopted technique for performing controller software/hardware integration testing as well as controller/controller integration testing. Having real-time capable models that are correlated to physical hardware being controlled is key to successful implementation of hardware in-the-loop testing. Because models for hardware in-the-loop must be developed in a short amount of time and then stay in sync with the design through design changes, a best practice is to obtain such models from the system-level model used for requirements analysis and design trade offs. This way, one model can address the need of both requirements analysis and integration testing, reducing redevelopment of models and ensuring consistency between two process steps. While there has been significant progress made in recent years on real-time simulator technologies, including I/O accuracy, use of off-the-shelf hardware, acceleration using parallel processing, the process by which a system level simulation model is to be reused for hardware in-theloop testing is not very well understood. This paper starts by examining options for developing a system level simulation model. When limited to causal modeling techniques, the process of creating models is often cumbersome and time-consuming. Many engineers find non-causal (or acausal) modeling methods to be much more intuitive. However, getting acausal models to run in real-time requires careful upfront planning and, when required, methodical reduction. The remaining sections of the paper deal with effective techniques for physical model development and reduction.

The performance and design criteria for seat systems require that the seat be lighter for reduced fuel consumption while still meeting the safety requirements as required by legislation. The safety requirements for seats include headrests and seat back static and dynamic structural performance, seat belt anchorage and luggage retention capability, child seat anchorage and top tether requirements as defined by pertinent regulation. The interior space constraints require that the seat be thinner. The seat design is expected to address the growing concern for environmental friendliness. In addition to these main criteria, various additional features such as adjustable and stow-able design are required for customer delight. All these design objectives should be met within a given cost target. Conventional seating systems include a steel frame, with springs attached to provide support and flexibility to foam cushions. The steel frame is made up of several parts welded together. Weight of the seating system can be 80% of the weight of the interior of the vehicle. This paper deals with plastic front and rear seat designs that provide more than 20% weight reduction. The lighter seat improves the vehicle fuel efficiency, reducing CO2 emissions and the material of construction includes recyclable plastics and “green” polyurethane foam, making this design eco-friendly. Low cycle time of molding, reduced part count and assembly time, optimized contours for comfort and reduced material consumption lead to cost competitive design. The optimized structural properties and processability of various thermoplastics and thermoset polymer systems offer good stiffness and impact properties at fast cycle times. The combination of ease of processing, excellent mechanical behavior, dimensional stability and a wide operating temperature window make these materials a suitable choice for construction of seat systems. It is critical to combine the seat structure design with the appropriate choice of foam to provide comfort to the passenger, while minimizing weight and costs. Various implicit and explicit finite element analyses codes are used to simulate the process, structural and crash behavior in order to optimize the design, minimizing weight while meeting various regulatory requirements. This paper deals with the design, process, materials and the development methodology for plastic seats to meet various structural regulations and help fulfill the environmental demands on emissions and fuel consumption.

Flex Track Drilling systems are being used increasingly in aerospace applications providing low cost, highly efficient automated drilling systems. Certain applications like circumferential splice drilling on large size airplane fuselages require multi spindle flex track systems working in tandem to meet production efficiency requirements. This paper discusses the development of a multi spindle flex track drilling system for a circumferential splice drilling on the 777 airplane. The multi spindle system developed uses a variety of flex track carriages attached to the flexible vacuum tracks to allow for offset or wide inside drilling. Segmented machine programmes allow these multiple machines to be deployed on the same circumferential splice on the airplane providing the multi spindle system. Interfacing of the multiple spindles is achieved by a custom OEM interface using a single screen thereby ensuring simplicity of operation. A central database location ensures that all programmes are current and maintains operational status of all holes being drilled. Tool life monitoring is also provided to ensure consistent tool changeovers for maintaining hole quality and process capability. Flexible track lengths can be spliced together for long lengths and shortened for clearance or areas using smaller programmes. This paper also discusses the development of the carriage hardware specific to the 777 airplane requirements using the methodology of adapting existing flex track system designs as well as point design specific to the 777 Fuselage Circumferential Splice Drilling Application. INTRODUCTION In the fall of 2007, a Boeing internal cross-functional team was chartered to investigate implementation of automation technologies to mitigate the challenges that have increased with higher production rates in 777 fuselage assembly. A technical report published by this team proposed the application of selective automation to the 777 Fuselage Integration processes. By implementing selective automation the benefits of reduced repetitive injuries, reduction of skin quality defects and lower cycle time in some of the fuselage integration processes would be realized. An additional benefit would also be the resultant consistent/repeatable and reliable process. These improvements would drive a better work environment, which would reflect on better attendance, less attrition and a higher employee morale. This Technology implementation would result in an improved product to the customer. After a detailed investigation of current build processes of longitudinal and circumferential splices it was determined that the focus should be on automation of the drilling of the circumferential splice on the 777-300 airplane, Aft fuselage section. To reduce developmental cost it was determined to use as much as possible offthe-shelf technologies with minimal developments needed to adapt to the 777 airplane requirements. Also taken into consideration was that the equipment chosen would need to be adaptable with few or no changes to current Floor Assembly Jig (FAJ) or floor mounted equipment (FME). SELECTIVE AUTOMATION PROPOSAL A technical evaluation of the longitudinal and circumferential splice drilling and fastening processes revealed that application of automation to selected portions of these processes would provide the greatest benefit for the investment incurred. On circumferential splice drilling and fastening processes it was discovered that the drilling processes constituted almost 70% of the total process time. These drilling processes included pilot drilling of holes, full size drilling of holes as well as countersinking processes. Any implementation of automation on these drilling processes would yield major gains in productivity including additional benefits of improved ergonomics, improved skin quality and overall an improvement of the production process and overall product quality. The study of the automation of the fastening processes for the circumferential splices yielded that gains realized by automation would not result in great improvements in productivity for these processes. Some of the gains would be offset by the additional process monitoring time as required by engineering specifications for the automated fastening processes. By focusing on the drilling processes only of the circumferential splices, the automation equipment requirements were also greatly simplified due to the omission of additional fastener insertion end effectors, clamp up equipment etc. This allowed the team to evaluate more options for the automated drilling equipment as many suppliers met the specifications for the drilling equipment but not for the drilling/fastening equipment, making it easier to obtain off the shelf automated drilling equipment. A time study along with an ergonomic study, combined with production process data including quality charts was compiled to help arrive at a decision for development and implementation of selective automation in 777 Fuselage Integration.

Legislative bodies are directing that automotive products comply with stringent safety levels. The liability for the safety of passengers in an automobile has traditionally been quite complex. Other transport sectors are externally regulated, and liability lies with the manufacturer or the transport service provider. The automotive industry is self-regulated and the individual driver carries a significant liability. Software and electronics increasingly provide greater control of automotive safety, possibly reducing driver liability, and increasing the need for more formal software development methods. The automotive business model, however, also presents challenges to the effective use of formal methods. An automotive design change costing €600 per vehicle could consume 100% of gross margin. In aviation, this cost represents 0.01% of gross margin. [1] [2]. The automotive industry is responding to the increasing impact of automotive software with the development of standards such as AUTOSAR [3], and EU funded projects such as ATESST [4] and EASIS [5]. They propose architectures which might deliver the benefits of best software engineering practice to the industry. In terms of safety, they recommend existing accepted standards such as IEC61508 [6], which stipulates various formal methods for the development of safetycritical software. However, IEC61508 does not compare specific formal methods in terms of their suitability to industry. This paper discusses the suitability for industry of formal methods of specification and verification. It provides a classification which looks at categories such as commercialization; capacity to solve industry-scale problems; cost effectiveness, etc. The paper looks at the relevance of the classification in terms of the challenges and constraints of the automotive domain and discusses how it might facilitate the engineer to make design decisions which improve safety in a cost effective manner.

High altitude ice crystals can pose a threat to aircraft engine compression and combustion systems. Cases of engine damage, surge and rollback have been recorded in recent years, believed due to ice crystals partially melting and accreting on static surfaces (stators, endwalls and ducting). The increased awareness and understanding of this phenomenon has resulted in the extension of icing certification requirements to include glaciated and mixed phase conditions. Developing semi-empirical models is a cost effective way of enabling certification, and providing simple design rules for next generation engines. A comprehensive ice crystal icing model is presented in this paper, the Ice Crystal Icing ComputationaL Environment (ICICLE). It is modular in design, comprising a baseline code consisting of an axisymmetric or 2D planar flowfield solution, Lagrangian particle tracking, air-particle heat transfer and phase change, and surface interactions (bouncing, fragmentation, sticking). In addition, an efficient particle tracking method has been developed into the code, which employs the representative particle size distribution at each injection location and a deterministic particle sticking method by using an in-situ particle based scaling factor without aborting the particle trajectories. Various time integration algorithms, including implicit and explicit Euler and Runge-Kutta methods, are discussed and the effect on an acceptable timestep investigated. The model then improves on those available in the literature in three ways: firstly, an adaptation of the Extended Messinger Model (EMM) to mixed phase conditions is incorporated, improving the fidelity of the ice accretion prediction compared with the classical Messinger model. Secondly, an experimentally-derived model for sticking efficiency improves the accuracy of the continuity equation in the EMM; thirdly a simple model for integrating two-way coupling of mass and energy is proposed.

As part of the U.S. Environmental Protection Agency’s (EPA’s) continuing assessment of advanced light-duty automotive technologies in support of regulatory and compliance programs, a 2018 Toyota Camry A25A-FKS 4-cylinder, 2.5-liter, naturally aspirated, Atkinson Cycle engine with cooled exhaust gas recirculation (cEGR) was benchmarked. The engine was tested on an engine dynamometer with and without its 8-speed automatic transmission, and with the engine wiring harness tethered to a complete vehicle parked outside of the test cell. Engine and transmission torque, fuel flow, key engine temperatures and pressures, onboard diagnostics (OBD) data, and Controller Area Network (CAN) bus data were recorded. This paper documents the test results under idle, low, medium, and high load engine operation. Motoring torque, wide open throttle (WOT) torque and fuel consumption are measured during transient operation using both EPA Tier 2 and Tier 3 test fuels. The design and performance of this 2018 2.5-liter engine is described and compared to Toyota’s published data and to EPA’s previous projections of the efficiency of an Atkinson Cycle engine with cEGR. The Brake Thermal Efficiency (BTE) map for the Toyota A25A-FKS engine shows a peak efficiency near 40 percent, which is the highest value of any publicly available map for a non-hybrid production gasoline internal combustion (IC) engine designed to run on 91 RON fuel. Further improvement is possible by application of fixed discrete or full continuous cylinder deactivation, both of which are currently in production on other engines.

The process of developing, parameterizing, validating, and maintaining models occurs within a wide variety of tools, and requires significant time and resources. To maximize model utilization, models are often shared between various toolsets and experts. One common example is sharing aircraft engine models with airframers. The functionality of a given model may be utilized and shared with a secondary model, or multiple models may run collaboratively through co-simulation. There are many technical challenges associated with model sharing and cosimulation. For example, data communication between models and tools must be accurate and reliable, and the model usage must be well-documented and perspicuous for a user. This requires clear communication and understanding between computer scientists and engineers. Most often, models are developed by engineers, whereas the tools used to share the models are developed by computer scientists. Computer scientists often struggle with implementing methods for exchanging data between models while simultaneously maintaining the usability that engineers desire, and engineers often struggle with utilizing the tools that computer scientists have developed. In the process of developing tools and interfaces for model sharing and co-simulation, much is lost in the communication between computer scientists and engineers. This paper seeks to ease the communication barrier associated with model sharing and model co-simulation by clearly and simply discussing some of the commonly associated challenges and solutions, and then providing clear and concise implementation examples.

This paper will initiate a discussion on automotive industry requirements and associated standardization of digital human modeling software (DHMS) as applied to manufacturing operations. Industry benefits of standardization are vast, making it difficult to identify and provide an exhaustive list. High value benefits will be listed for the purpose of this discussion. Industry users of DHMS will benefit by the standardization of an application programming interface, classification of anthropometry and simulation data translation. A list of high value standardization goals will be provided for the purpose of this discussion. Two examples of standardization goals include 1) a reduction in the time and cost required to integrate research results into commercial software and 2) improved simulation data transfer and linkages between DHMS to simplify the use of multiple tools when analyzing a single problem. This paper will provide an introduction to and proposal for standardization of DHMS. It will introduce the concept of a digital human modeling (DHM) architecture. It will also include a proposal on areas of standardization for future discussion.

The Kalman and Vold-Kalman order tracking filters have been implemented in commercial software since the early 90's. There are several mathematical formulations of filters that have been implemented by different software vendors. However, there have not been any papers that have been published which sufficiently explain the math behind these filters and discuss the actual implementations of the filters in software. In addition, upon generating the equations represented by these filters, solving the equations for datasets in excess of several hundred thousand datapoints is not trivial and has not been discussed in the literature. The papers which have attempted to cover these topics are generally vague and overly mathematically eloquent but not easily understandable by a practicing engineer. This paper will attempt to solve that problem by explaining the filters' formulations and behavior in very straight forward and practical terms through the use of both equations and example datasets.

The geometrical design of the airbox for an internal combustion engine has a significant effect on the pressure loss in the entire inlet tract. Due to the location of the airbox, its size and shape is usually limited as a result of the proximity to other underbonnet features.The shape is also limited by manufacturing, assembly and NVH considerations. The complexity of the unsteady flow through the airbox and the constraints placed upon it by the available volume in the under-bonnet area make this a challenging design task. This paper reviews the current thinking on methods used to optimize Computational Fluids Dynamics (CFD) problems and how this would apply to the optimization of an airbox for an internal combustion engine. The paper then goes on to detail the findings of the initial validation work on the CFD method for predicting the pressure loss through an airbox. An optimization case study is then presented based on one of the models used for the validation.

The ability to personalize air travel through the use of an on-demand, highly distributed air transportation system will provide the degree of freedom and control that Americans enjoy in other aspects of their life. This new capability, of traveling when, where, and how we want with greatly enhanced mobility, accessibility, and speed requires vehicle and airspace technologies to provide the equivalent of an internet PC ubiquity, to an air transportation system that now exists as a centralized hub and spoke mainframe NASA airspace related research in this new category of aviation has been conducted through the Small Aircraft Transportation (SATS) project, while the vehicle technology efforts have been conducted in the Personal Air Vehicle sector of the Vehicle Systems Program. The PAV sector technology research conducted over the past several years is described, including intelligent avionics for ease of use, integrated low noise propulsion, advanced internal combustion engines, low cost variable pitch ducted propellers, lean design structures, quality assurance based certification regulations, a laminar flow fuselage with integrated aero-propulsion, advanced vehicle concepts, and high density airspace simulations. INTRODUCTION This paper provides the technology development portion of a trilogy of papers that report out the results of the Personal Air Vehicle (PAV) Sector of the NASA Vehicle Systems Program (VSP). The NASA VSP was cancelled over the past year as part of the Aeronautics Enterpr ise restructur ing, being replaced by the Fundamental Aeronautics Program. Since no further investment is currently planned relating to small aircraft, transitioning this research to industry is imperative to maximize the potential societal benefit. These three papers present the project research, incorporating the overarching system of systems perspective of th is vehicle sector (The Third Wave of Aeronautics: OnDemand Mobility SAE paper 2006-01-2429), the technology portfolio investment required to enable PAV sector capabilities (NASA Personal Air Transportation Technologies – SAE Paper 2006-01-2413), and the integrated vehicle concept development required to achieve a balanced and complementary technology portfolio (Next Generation NASA GA Aircraft Concept – SAE Paper 2006-01-2430). The PAV Sector was the smallest of the six VSP vehicle sectors, with a full cost investment of $10 million dollars over the 3 years. While not the solution to all travel, PAVs would provide a new, better choice for mid range trip distances of 50 to 500 miles where airlines and automobiles provide poor block speed service. Since this travel market accounts for almost half of all person trip miles in the U.S, it is more than a niche market that deserves effective cost to uti l i ty solutions to provide societal benefit. This supplemental personal air transportation network would do what car, airline, or rail could never do; combine ondemand access with high speed to yield a direct extension of the wireless, fax, and internet on-demand service age. At the same time, this new capability could maximize transportation capacity, robustness, and productivity. The f irst figure indicates how specific technology investments could yield integrated solutions which would offer increasingly distributed air operation capability. An analogy is presented to the computer industry which has transformed itself over the past 30 years from a highly centralized market solution, into an incredibly distributed market solution. This computer market revolution was driven by a combination of performance, packaging and cost technologies, which when combined with ease of use technologies (the Windows and Mac operating systems), the result was a much broader market with greatly increased revenues, while serving the customer better. The current aviation market offers an ‘innovator’s dilemma’ of trying to meet entrenched market needs through ever smal ler incremental improvements to existing customers, instead of developing disruptive technologies that create new value networks. A detailed discussion of this potential ‘Third Wave of Aeronautics: On-Demand Mobility’ is presented in SAE paper 2006-01-2429. At the commencement of the PAV sector efforts, an industry/academia/government working group was established to provide guidance on technology content and priorities. In addition, an independent review panel o f i n dustry ‘grey-beards’ provided continuous improvement of the technology project efforts. These meetings established a PAV sector GOTChA (Goals, Objectives, Technology Challenges, and Approaches – see Appendix) documentation set which decomposed efforts into a capabil i ty-based research plan with tracking metrics. These desired end state capabilities are listed below in Table 1, and are discussed in more detail within each technology approach section. The technology approaches were prioritized into near-term 5year and far-term 15-year efforts, with available funding limiting current research to primarily the near-term set except for a few exploratory far-term efforts. A n important distinction which occurred at the start of the research planning was defining the PAV as a selfoperated vehicle meeting personal transportation needs; therefore a PAV is not necessarily personally owned or maintained, since fractional ownership offers dramatic benefits in cost through increased utilization. A n important realization from this capability set is that the PAV technology efforts are not centered around achieving improved performance, but instead focus on improving the ‘ilities’ of the operational experience. In fact, as with most disruptive technologies, the focus is no t on improv ing ex is t ing cus tomer demands (established pilots) for improved performance, but instead meeting new customer requirements that would permit the current market to greatly expand, and reach greater economies of scale for all. Required Capability SOA 5-Years 15-Years Ease of Use (equiv. safety) SEP-IFR* Haptic Auto-like Community/Cabin Noise SEP Motorcycle Auto Emissions (HC/NOX/Lead g/mile) .5/1.0/.2 .05/.10/0 .03/.06/0 Acquisition Cost (2004 $ K) 450 150 100 Safety (accidents/100K hr) 6.5 2.0 .5 Cruise speed (mph) 200 200 150 Range (statute miles) 600 600 300 Efficiency (mpg) 13 16 40 Field Length (feet to clear obstacle) 250

This keynote paper presents a concise survey of the international research carried out for developing spacecraft oriented (variable conductance) two-phase thermal control systems, based on passive or active control of fluid manipulation. It focuses on variable conductance heat pipes, based on a control using non-condensable gas. It illustrates the historical development and arguments why these relatively simple two-phase thermal control systems are the preferred solution to meet the different restrictions induced by the requirement specifications of many, relatively low power (say up to 1 kW) applications space. The paper briefly revisits alternative control approaches, considered in the past. It also discusses a novel approach, currently being investigated.

The potential of digital human modeling to improve the design of products and workspaces has been limited by the time-consuming manual manipulation of figures that is required to perform simulations. Moreover, the inaccuracies in posture and motion that result from manual procedures compromise the fidelity of the resulting analyses. This paper presents a new approach to the control of human figure models and the analysis of simulated tasks. The new methods are embodied in an algorithmic framework developed in the Human Motion Simulation (HUMOSIM) laboratory at the University of Michigan. The framework consists of an interconnected, hierarchical set of posture and motion modules that control aspects of human behavior, such as gaze or upper-extremity motion. Analysis modules, addressing issues such as shoulder stress and balance, are integrated into the framework. The framework encompasses many individual innovations in motion simulation algorithms, but the primary innovation is in the development of a comprehensive system for motion simulation and ergonomic analysis that is specifically designed to be independent of any particular human modeling system. The modules are developed as lightweight algorithms based on closed-form equations and simple numerical methods that can be communicated in written form and implemented in any computer language. The modules are independent of any particular figure model structure, requiring only basic forward-kinematics control and public-domain numerical algorithms. Key aspects of the module algorithms are “behavior-based,” meaning that the large amount of redundancy in the human kinematic linkage is resolved using empirical models based on laboratory data. The implementation of the HUMOSIM framework in human figure models will allow much faster and more accurate simulation of human interactions with products and workspaces using high-level, task-based control. INTRODUCTION Digital human figure models (DHM) are now widely used for ergonomic analysis of products and workplaces. In many organizations, DHM software is a tool of first resort for answering questions relating to physical interaction between people and objects. Yet any objective appraisal of the technology would conclude that the current reality of DHM software capability is far from the promise of a “digital human” that can interact realistically with products and environments. This paper is focused on efforts to improve the ability of DHM software to simulate physical posture and motion. Nearly every other aspect of DHM functionality also warrants improvement, including body shape representation, strength simulation, and cognitive function, but posture and motion are critical to the primary applications of DHM to the assessment of physical tasks. Posture simulation is as old as computerized manikins, because the manikin must be postured before an analysis can be conducted. Important early work was performed by Ryan for the U.S. Navy (Ryan 1970). Porter et al. (1993) summarized applications of digital human models in vehicle ergonomics during the early years of personal computers, at which time few of the current commercial DHM software tools were in use. Chaffin (2001) presented case studies of the expanding use of DHM for both product and workplace design and assessment. As evidence of the importance of posture and motion simulation, dozens of papers in the SAE literature and in other forums have presented a wide variety of methods for human simulating postures and motions, including multiple-regression (Snyder et al. 1972); analytic and numerical inverse kinematics (Jung et al. 1995; Tolani et al. 2000); optimization-based inverse kinematics (Wang and Verriest 1998); differential inverse kinematics (Zhang and Chaffin, 2000); functional regression on stretch-pivot parameters (Faraway 2000); scaling, warping, and blending of motion-capture data (Park et al. 2002; Faraway 2003; Monnier et al. 2003; Park et al. 2004; Dufour and Wang 2005); and many 2006-01-2365 The HUMOSIM Ergonomics Framework: A New Approach to Digital Human Simulation for Ergonomic Analysis Matthew P. Reed, Julian Faraway, Don B. Chaffin and Bernard J. Martin University of Michigan

Time estimation is a fundamental behavioral characteristic used by all humans when completing task sequences in the real world. Properly characterizing the manner that humans engage in time-critical tasks, as well as the interaction among these tasks, is necessary when developing reliable computational models of human performance to be used to simulate real-world humansystem performance. The current paper introduces the notion of estimating time available, time required, and time onset to complete behaviors within real environmental contexts. It also summarizes relevant research on over- and under-estimating of time, and outlines critical factors ‐ workload and windows of opportunity ‐ that impact estimates of time. The paper culminates in the development of a new domain- and platform-independent conceptual model, dubbed TEMPORA, the Time Estimation Model for Predicting Onset, Required and Available time. The relationship between this conceptual model and the general requirements specifications for computational model development are highlighted.

The study done by the U.S. National Highway Traffic Safety Administration (NHTSA) shows that developing automotive collision warning and avoidance systems will be very effective in order to significantly reduce fatalities, injuries and associated costs. In order to develop an automotive collision warning and avoidance system, it will be necessary that the vehicles should be able to exchange (in real-time) their dynamic information such as speed, acceleration, direction, relative position, status of some devices like brake, steering wheel, gas pedal, etc. The only feasible way to exchange the vehicles’ dynamic information will be through the use of wireless communication technology. However, the wireless link setup time and communication latencies should be under certain bounds so that the vehicles can appropriately react on time to avoid collisions. This paper will present results from an experimental setup that simulates inter-vehicle communications. The experimental setup has been prepared using a number of CAN and Bluetooth modules. The communication system of each vehicle has been simulated using several CAN nodes and a wireless module. In addition, a number of stand-alone Bluetooth modules have been used in the experiment to increase the wireless communication traffic through the air. An event such as pressing the brake pedal or turning on the turn signals has been simulated using buttons. At the occurrence of an event, the simulated vehicle system automatically sends a message through its CAN bus, then it broadcasts the message via its wireless module. Other simulated vehicles receive the message via their wireless modules and then send the message via their CAN buses. Eventually the message triggers some actuators in the destination vehicles. The latencies have been measured from the time an event occurred and until the time some actions have been taken by the actuators of the destination vehicles. The paper presents results on inter-vehicle communication latencies under various types of traffic conditions. Other researchers and engineers will get valuable information from this paper which will help them in designing wireless communication systems for the future vehicles. INTRODUCTION In this paper, we design a system, as shown in Figure 1, to simulate inter-vehicle communication system. Two vehicles, A and B, have CAN-wireless gateway connected to their in-vehicle CAN bus. The gateway on one vehicle converts its in-vehicle CAN message into wireless message and transmits it onto the air. The other vehicle then receives the wireless message and converts it into a CAN message. This way, these two vehicles communicate with each other.

In this paper, we propose a secure protocol for intervehicle communication (IVC) networks without the use of centralized roadside infrastructure. Future vehicles may use wireless IVC networks to exchange safety-critical information among each other. IVC networks do not have a centralized control, and instead rely on vehicles to coordinate with each other to exchange information. Because of the open medium, security is a concern in IVC networks. Vehicles need a mechanism to authenticate the safety-critical information that will be exchanged in IVC networks. A trusted third party Certificate Authority (CA) can provide such a mechanism through public-key certificates. However, the disadvantage of using public-key certificates is that drivers can identify each other. The certificate will allow privacy concern. In this paper, we propose to use RSA public key algorithm and Digital Signature Algorithm (DSA) to solve the security and privacy concerns in IVC networks. The paper presents a detailed description of our protocol, and shows its performance analysis in terms of processing times.

The need for active safety, highway guidance, telematics, traffic management, cooperative driving, driver convenience and automatic toll payment will require future intelligent vehicles to communicate with other vehicles as well as with the road-side infrastructure. However, inter-vehicle and vehicle to roadside infrastructure communications will impose some security threats against vehicles’ safety and their proprietary information. To avoid collisions, a vehicle should receive messages only from other authentic vehicles. The internal buses and electronics of a vehicle must also be protected from intruders and other people with malicious intents. Otherwise, a person can inject incorrect messages into an authentic vehicle’s internal communication system and then make the vehicle transmit wrong information to the other vehicles within the vicinity. Such an event may have catastrophic consequences. Thus, a detailed study of the security needs of the future vehicles is very important. In this paper, we will present the results of a comprehensive study related to various types of security threats against a vehicle’s electronic communication system. The paper will identify various types of security attacks against a vehicle’s electronic system. The paper will also address various issues that are related to the design of secure microcontrollers, secure electronic modules, secure communications through the vehicle’s internal buses and privacy-protected secure peer-topeer communications.

To overcome future stringent regulations on pollutant emissions and to decrease CO emissions and fuel consumption, hybrid vehicles seem to be one of the near future most promising technologies. This type of car uses complex energy management and control strategy. Simulation can be very useful for the development of such a control system. This paper highlights a new library developed under the AMESim software that enables the simulation of complex interactive systems in vehicles. In addition, the possibility to combine with other AMESim modules, allows the users to add more complexity to any of the sub-components of the vehicle. As an illustration of this new tool capability, we propose in this paper a simulation example of the Prius, the most known hybrid vehicle which was the first commercial vehicle in 1997 and selected as the 2004 Car of the Year in Europe. Comparisons between measurements and simulations of the response of different components are presented on different driving cycles.

A cryofreezer system is being evaluated as a new method of compressing and storing carbon dioxide (CO2) in an Advanced Life Support (ALS) Environmental Control and Life Support System (ECLSS). A cryocooler is used to provide cold temperatures and heat removal while CO2 freezes and accumulates around a coldtip. The CO2 can then be stored as a liquid or high-pressure gas after it has been accumulated. This system was originally conceived as an In-Situ Resource Utilization (ISRU) application for collecting CO2 from the Mars atmosphere to be converted to methane fuel with a Sabatier reaction. In the ALS application, this system could collect CO2 from the International Space Station (ISS) Carbon Dioxide Removal Assembly (CDRA) for delivery to the Sabatier reactor. The Sabatier reaction is an important part of proposed Air Revitalization System (ARS) for ALS, and technology sharing is often possible between ISRU and ARS applications in CO2 processing systems. A prototype system developed and initially tested by Lockheed Martin Astronautics is now being evaluated in the Air Revitalization Technology Evaluation Facility (ARTEF) at NASA Johnson Space Center (JSC). This paper will discuss testing conducted through December 2004 to examine the performance and capacity of the system under a variety of input conditions. A simulation of the system was developed simultaneously using the Aspen Custom Modeler (ACM) software package. Several approaches using varying levels of detail could be used when modeling the system, and this paper will discuss the assumptions and choices made in this simulation, as well as the validity of the simulation for predicting performance of the prototype unit.