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AbstractThis study aims to: (1) apply computer-aided engineering to automotive design, (2) investigate the dynamic load transmission lines causing vibrations in the truck cabin, and (3) analyze and compare vibration characteristics on different road types. A model of a light truck was numerically examined. A frequency response function and a dynamic simulation were used to study how the road surface’s excitation force affects structure vibration. The Multi-body Dynamics simulation was performed to estimate the external force acting on the vehicle. In the case of a flat road at a speed of 60 km/h, the counterforce values almost remain constant, corresponding to 1 G. In the case of a vehicle crossing a hole, at a speed of 30 km/h, the counterforce is about 3.57 and 5.67 G at the front and rear axles, respectively. On a bumpy road, at 30 km/h, the counterforce is about 3.3 G on the front axle and 7.2 G on the rear axle. The FRF analysis shows that the truck cabin’s resonant frequency is 29 to 32 Hz. [ABSTRACT FROM AUTHOR]

The article describes the application of a vehicle simulation model to assess the driving hazards that arise due to changes in the tyre–road adhesion during a lane change. An experimentally verified vehicle dynamics model was used. The typical single lane change maneuver, performed on dry concrete, wet concrete, and ice-covered roads, was simulated for three vehicle speeds. The disturbance was introduced as a changed tyre–road adhesion on the target lane. Typical sinusoidal (one-period) input was applied to the steering wheel. Adhesion change may lead to an accident when considering the driver's reaction time. An original control algorithm has been built. It is the driver assistance system with a double PID controller of the steering wheel angle. The system parameters were determined based on the principles recommended in the automatic control engineering monographs. The controller fulfils its tasks for motion at very high speeds on a homogeneous road surface and for the case where the tyre–road adhesion is changed during a maneuver. Thanks to this, the threat can be avoided. [ABSTRACT FROM AUTHOR]

A deep understanding of non-smooth dynamics of vehicle systems, particularly with dry friction damping offer valuable insights into the design and optimization of railway vehicle systems, ultimately enhancing the safety and reliability of railway operations. In this paper, the two-parameter dynamics of a non-smooth railway wheelset system incorporating dry friction damping are investigated. The effect of the crucial parameters on the complexity of the evolution process is comprehensively exposed by identifying different dynamic responses in the two-parameter plane. In addition, the multistability and the various routes transition to chaos for the system are also discussed. It is found that dry friction induces highly complex dynamics in the system, encompassing a range of behaviors such as periodic, quasi-periodic, and chaotic motions. These intricate dynamics are a direct result of the interplay between multiple parameters, such as speed and damping coefficients, which are critical in determining the system's stability and performance. The presence of multistability further complicates the system, resulting in unpredictable transitions between different motion states. [ABSTRACT FROM AUTHOR]

The acquisition of vehicle driving status information is a key function of vehicle dynamics systems, and research on high-precision and high-reliability estimation of key vehicle states has significant value. To improve the state observation effect, a vehicle sideslip angle estimation method adopting a robust bias compensation Kalman filter and adaptive weight fusion strategy is proposed. On the basis of the extended Kalman filter algorithm, and with the goals of estimation exactitude and robustness, considering the potential signal deviation, a vehicle state robust deviation compensation Kalman filter estimation algorithm considering bias compensation and residual covariance matrix weighting is proposed. Meanwhile, considering the adaptive and dynamic adjustment capabilities of the observation system in complex state-change scenarios, an estimation strategy based on adaptive weight fusion and a model-based estimator is proposed. The results confirm that the robust bias compensation Kalman filter can ensure estimation exactitude and robustness when the vehicle state fluctuates greatly, and the proposed fusion strategy can ensure that the vehicle maintains optimal estimation performance during operating condition switching. [ABSTRACT FROM AUTHOR]

This article studies cooperative adaptive cruise control (CACC) for vehicle platoons with consideration of the unknown nonlinear vehicle dynamics that are normally ignored in the literature. A unified data‐driven CACC design is proposed for platoons of pure automated vehicles (AVs) or of mixed AVs and human‐driven vehicles (HVs). The CACC leverages online‐collected sufficient data samples of vehicle accelerations, spacing, and relative velocities. The data‐driven control design is formulated as a semidefinite program that can be solved efficiently using off‐the‐shelf solvers. Efficacy of the proposed CACC are demonstrated on a platoon of pure AVs and mixed platoons with different penetration rates of HVs using a representative aggressive driving profile. Advantage of the proposed design is also shown through a comparison with the classic adaptive cruise control (ACC) method. [ABSTRACT FROM AUTHOR]

The electric power steering system is used to improve comfort and steering feel for the user. In this article, we propose to use an integrated nonlinear control strategy for the electric steering system, which is described based on a complicated dynamic model. This work provides two new contributions. First, this control algorithm combines backstepping and proportional–integral (PI) techniques with parameters adjusted by a fuzzy algorithm, so it is called Fuzzy proportional–integral backstepping control (FPIBSC). The output of the PI algorithm is the input of the backstepping technique, while system stability is evaluated based on the Lyapunov function with virtual control variables. Second, road reaction torque is calculated based on a spatial dynamic model, which considers the influence of many other factors. Numerical simulation methods are used to evaluate the performance of the system. According to research findings, the value of the steering motor angle (controlled object) continuously tracks the desired value with negligible error. Under some specific conditions, the error between signals can be reduced to zero. In addition, other outputs that are obtained from the FPIBSC algorithm also tend to follow the reference signal with high accuracy. The phase difference phenomenon only occurs when using the conventional backstepping algorithm instead of FPIBSC. The assisted torque increases as speed decreases or the driver torque increases. In general, the system's stability is always guaranteed under many different simulation conditions. [ABSTRACT FROM AUTHOR]

This study introduces fBrake, a novel simulation method now designed for use in periodic technical inspections of M1 and N1 vehicle categories, addressing challenges posed by Directive 2014/45/EU. The directive mandates that braking efficiency must be measured relative to the vehicle's maximum mass, which often results in underperformance during inspections due to vehicles typically being unladen. This discrepancy arises because the maximum braking forces are proportional to the vertical load on the wheels, causing empty vehicles to lock their wheels prematurely compared to laden ones. fBrake simulates the braking forces of unladen vehicles to reflect a laden state by employing an optimal brake-force distribution curve that aligns with the vehicle's inherent braking behavior, whether through proportioning valves or through electronic brake distribution systems in anti-lock-braking-system-equipped vehicles. Our methodology, previously applied to heavy vehicles, involved extensive experimentation with a roller brake tester, comparing the actual braking performances of dozens of vehicles to those of their simulated counterparts using fBrake. The results demonstrate that fBrake reliably replicates the braking efficiency of laden vehicles, validating its use as an accurate and effective tool for braking system assessments in periodic inspections, irrespective of the vehicle's load condition during the test. This approach ensures compliance with regulatory requirements while enhancing the reliability and safety of vehicle inspections. [ABSTRACT FROM AUTHOR]

Automated vehicles equipped with adaptive cruise control systems (ACC-AVs) are prevalent and the ensuing issue is the feasibility of ACC-AVs' operation on the roads. This study investigates the feasibility of road horizontal curve designs for ACC-AVs from a vehicle dynamics perspective. Following the scenario generation framework, we created and tested several scenarios featuring horizontal geometric elements and design speeds, conducting a safety evaluation based on the critical adhesion coefficient, lateral acceleration, lateral-load transfer rate, together with driving comfort indicators. Results indicate that ACC-AV can navigate on road curves designed with a common minimum radius (Rmin_com) effectively at speeds over 60 km/h , comparable to conventional vehicles. However, both Rmin_com and limited minimum radius (Rmin_lim) designs show limitations. Additionally, the feasible radius ranges for ACC-AV reveal the capability to safely handle sharper curves and maintain higher speeds, suggesting potential for adaptable road design in complex environments. Finally, minimum radius ranges were summarized for ACC-AV safe and comfortable operation on road curves, unveiling the potential risks and reminding designers in curve design controls for ACC-AVs. [ABSTRACT FROM AUTHOR]

Axle-box bearings are directly affected by wheel–rail impacts as fixedly connected to wheelset. As an inevitable wheel-failure, wheel flat can cause severe wheel-rail impact, which may deteriorate the performance of axle-box bearings, even threatening train running safety. To investigate the dynamic response of axle-box bearings excited by wheel flat, two rigid-flexible coupled vehicle dynamics models of motor and trailer cars are developed. The axle-box bearing, flexible axle-box and wheelset are thoroughly established in trailer car model. The gear transmission system and flexible gearbox are further integrated into motor car model relative to trailer model. The accuracies of models are verified by the field-test results. The dynamic responses of axle-box bearings excited by wheel flat are analyzed. Results indicate that the vibration and dynamic forces acting on axle-box bearing augment with the increasing of flat length. The vibrations intensify gradually from wheelset, inner ring, and outer ring to axle-box, particularly increasing significantly with long flat lengths. Moreover, the dynamic forces within axle-box bearing first increase before decreasing with the growing operating speed. Being structurally difference, wheel flat exerts more significant effects on the axial and radial forces within the bearings of motor car than those of trailer car. [ABSTRACT FROM AUTHOR]

The perception system plays a crucial role by integrating LiDAR and various sensors to perform localization and object detection, which ensures the security of intelligent driving. However, existing research indicates that LiDAR is vulnerable to sensor attacks, which lead to inappropriate driving strategies and need effective attack recognition methods. Previous LiDAR attack recognition methods rely on fixed anomaly thresholds obtained from depth map data distributions in specific scenarios as static anomaly boundaries, which lead to reduced accuracy, increased false alarm rates, and a lack of performance stability. To address these problems, we propose an adaptive LiDAR attack recognition framework capable of adjusting to different driving scenarios. This framework initially models the perception system by integrating the vehicle dynamics model and object tracking algorithms to extract data features, subsequently employing Gaussian Processes for the probabilistic modeling of these features. Finally, the framework employs sparsification computing techniques and a sliding window strategy to continuously update the Gaussian Process model with window data, which achieves incremental learning that generates uncertainty estimates as dynamic anomaly boundaries to recognize attacks. The performance of the proposed framework has been evaluated extensively using the real-world KITTI dataset covering four driving scenarios. Compared to previous methods, our framework achieves a 100% accuracy rate and a 0% false positive rate in the localization system, and an average increase of 3.43% in detection accuracy in the detection system across the four scenarios, which demonstrates superior adaptive capabilities. [ABSTRACT FROM AUTHOR]

• This study tracks the roads with different collision density patterns over time. • A spatio-temporal network KDE method was used to compute collision densities. • Roads with various collision density patterns were grouped by clustering method. • Spatio-temporal and semantic analyses were conducted to profile the risky roads. • The developed method can help the transport department propose the traffic treatment. Introduction : Motor vehicle collisions are a leading source of mortality and injury on urban highways. From a temporal perspective, the determination of a road segment as being collision-prone over time can fluctuate dramatically, making it difficult for transportation agencies to propose traffic interventions. However, there has been limited research to identify and characterize collision-prone road segments with varying collision density patterns over time. Method : This study proposes an identification and characterization framework that profiles collision-prone roads with various collision density variations. We first employ the spatio-temporal network kernel density estimation (STNKDE) method and time-series clustering to identify road segments with different collision density patterns. Next, we characterize collision-prone road segments based on spatio-temporal information, consequences, vehicle types, and contributing factors to collisions. The proposed method is applied to two-year motor vehicle collision records for New York City. Results : Seven clusters of road segments with different collision density patterns were identified. Road segments frequently determined as collision-prone were primarily found in Lower Manhattan and the center of the Bronx borough. Furthermore, collisions near road segments that exhibit greater collision densities over time result in more fatalities and injuries, many of which are caused by both human and vehicle factors. Conclusions : Collision-prone road segments with various collision density patterns over time have distinct differences in the spatio-temporal domain and the collisions that occur on them. Practical Applications : The proposed method can help policymakers understand how collision-prone road segments change over time, and can serve as a reference for more targeted traffic treatment. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the last few decades, the role of vehicle dynamics control systems has become crucial. In this complex scenario, the correct real-time estimation of the vehicle's sideslip angle is decisive. Indeed, this quantity is deeply linked to several aspects, such as traction and stability optimization, and its correct understanding leads to the possibility of reaching greater road safety, increased efficiency, and a better driving experience for both autonomous and human-controlled vehicles. This paper aims to estimate accurately the sideslip angle of the vehicle using different neural network configurations. Then, the proposed approach involves using two separate neural networks in a dual-network architecture. The first network is dedicated to estimating the longitudinal velocity, while the second network predicts the sideslip angle and takes the longitudinal velocity estimate from the first network as input. This enables the creation of a virtual sensor to replace the real one. To obtain a reliable training dataset, several test sessions were conducted on different tracks with various layouts and characteristics, using the same reference instrumented vehicle. Starting from the acquired channels, such as lateral and longitudinal acceleration, steering angle, yaw rate, and angular wheel speeds, it has been possible to estimate the sideslip angle through different neural network architectures and training strategies. The goodness of the approach was assessed by comparing the estimations with the measurements obtained from an optical sensor able to provide accurate values of the target variable. The obtained results show a robust alignment with the reference values in a great number of tested conditions. This confirms that the adoption of artificial neural networks represents a reliable strategy to develop real-time virtual sensors for onboard solutions, expanding the information available for controls. [ABSTRACT FROM AUTHOR]

Due to the characteristics of smart material magnetorheological (MR) fluid, such as short response time and large controllable range, semi-active suspension based on MR fluid has been widely used. In order to improve the steering stability of vehicles, a semi-active suspension with tapered flow mode MR was proposed. The magnetic circuit of the proposed structure was designed, its dynamic model was established, and the finite element simulation analysis was carried out. By establishing the optimization objectives and constraints, the MR damper was optimized by NSGA-II and MOST algorithms. The vehicle dynamics model with MR damper was established, and the vehicle dynamics simulation was carried out under the control system based on the vehicle dynamics simulation software CarSim-Simulink before and after optimization. The results show that the NSGA-II optimized MR damper can reduce vehicle roll and significantly improve vehicle handling stability. This paper provides a new idea for improving vehicle handling stability by optimizing the MR damper. [ABSTRACT FROM AUTHOR]

With the expansion of electronics in recent decades, it is notorious to observe that embedded systems are increasingly necessary to improve people's quality of life and to facilitate the diagnosis of systems in general, ranging from pacemakers to control systems. The increased use of electronic components for technological support, such as telemetry systems, electronic injection, and automotive diagnostic scanners, enhances the perspective of data analysis through an embedded system aimed at vehicular systems. Thus, this work aims to design and implement an embedded data acquisition system for the analysis of vehicle vertical dynamics. The methodology for this study was structured into several stages: mathematical modeling of a motorcycle's mass-spring-damper system, coding for the Arduino microcontroller, computational data analysis supported by MATLAB software version 9.6, electronic prototyping of the embedded system, implementation on the vehicle, and the analysis of motorcycle vertical dynamics parameters. In addition, a mathematical modeling of the mass-spring-damper system was performed using the state-space method. The system was implemented on the Arduino microcontroller platform, enabling real-time data transfer from a motorcycle. The experimental results have successfully validated the proposed data acquisition system. [ABSTRACT FROM AUTHOR]

Connectivity is a key element enabling intelligent vehicles to communicate with each other and the Smart Road. In general, the connectivity is allowed by an On-Board Unit enabling the Vehicle to Everything communication. This paper proposes an innovative unit acting not only as a device allowing connectivity but also as an intelligent electronic control unit to perform advanced and adaptive control strategies able to give reference trajectories and actuator set-points to the low-level control systems of power-train and vehicle dynamics. In particular, based on a cascade model predictive control, an adaptive control strategy is proposed, considering time-varying parameters and information related to vehicle kinematics and dynamics. Such a strategy allows the vehicle to follow a certain origin-destination path in the inertial frame, based on an upper controller that considers a vehicle kinematic model so as to give speed references and target values for the steering angle at thewheels to the inner predictive control loop acting on both longitudinal and lateral vehicle dynamics. To check the effectiveness of the proposed approach, a comparison is made with existing cascade control strategies. The results show better safety and lane-keeping performance. Then, using Hardware-In-the-Loop testing for the proposed Intelligent On-Board Unit, the considered approach demonstrates robustness against parametric variations, signal delay and noise both in the Global Positioning System and in the yaw rate sensor. The achieved results show good robustness properties, safety performances and confirm the real-time execution of the cascade control strategy, paving the way to future developments necessary before tests in a real road scenario. [ABSTRACT FROM AUTHOR]

In this paper, the stability and Bautin bifurcation of a four-wheel-steering (4WS) vehicle system, by considering driver steering control, are investigated. By using the central manifold theory and projection method, the first and second Lyapunov coefficients are calculated to predict the type of Hopf bifurcation of the vehicle system. The topological structure of Bautin bifurcation, a degenerate Hopf bifurcation of the 4WS vehicle system, is presented in parameter space, and it reveals the dynamics of the vehicle system of different choices of control parameters. The influences of system parameters on critical values of the bifurcation parameter are also analyzed. It is shown that with the increase in the frontal visibility distance of the driver control strategy coefficient and the cornering stiffness coefficients of rear wheels, the critical speed increases. Nevertheless, the critical speed decreases with the increase in the distance from the center of gravity of the vehicle to the front axles, Driver's perceptual time delay, and cornering stiffness coefficients of the front wheels. [ABSTRACT FROM AUTHOR]

This paper introduces a design and analysis method of the intelligent multiple-vehicle system (IMVS) based on preview control in the environment of the vehicle to vehicle (V2V). Considering the time delay, the vehicle longitudinal dynamics system is constructed. The information flow between vehicles in the platoon is realized by the onboard sensors and V2V. Based on the actual data sampling and processing, the cooperative optimal preview control problem of the vehicle platoon stability system is discretized. The error is used as a term of the state vector to expand, and the original problem is transformed into an augmented global optimal control problem. The existence and stability of the controller solution are analyzed. The asymptotically stable optimal control law is obtained by using the state augmented matrix, and the global optimal preview controller of original platoon stability is obtained. The simulation results verify the effectiveness of the designed controller. The following error decreases with the increase of the preview step, which ensures the stability of the platoon. From the first follower to the tenth one, the average spacing error decreases by 92.9 %, and the average following error of velocity decreases from 3.97 to 1.56 %. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The structure of a steering system plays an important role in the vehicle's handling performance. Considering the convenience of changing the structural parameters of the steering system, the phase angle of universal joints and the initial angle of steering shaft are selected as the structural parameters to be studied in this paper. The kinematics of the steering system and the dynamics of the whole vehicle are analyzed theoretically. The simulation study shows that the phase angle mainly influences the fluctuation of the steering ratio, the initial angle mainly influences the symmetry of the steering ratio. The transient and steady-state objective evaluation indexes vary with the phase angle and the initial angle at a period of 180°. Through optimization research, it is demonstrated that the handling performance of a vehicle can be improved in the direction of the desired level by matching the initial angle and phase angle. [ABSTRACT FROM AUTHOR]

This paper studies the shiftability of the face dog clutch with chamfered teeth. The effect of the chamfer angle on the shiftability map and the probability are studied. In contrast to previous studies, a generalized mathematical model is developed based on the shiftability condition. The analysis considered two sets of cases: the overlap distance cases, and the chamfer side cases. The overlap distance cases locate the successful engagement position. The chamfer side cases investigate the effect of the system geometry and consider two cases. The results show that the chamfer angle has a negative effect on the dog clutch shiftability. Some geometric parameters show a different effect on the engagement probability for the rectangular tooth and chamfered tooth cases, and this behaviour is also analysed. [ABSTRACT FROM AUTHOR]

Vehicle dynamics control systems have a fundamental role in smart and autonomous mobility, where one of the most crucial aspects is the vehicle body velocity estimation. In this paper, the problem of a correct evaluation of the vehicle longitudinal velocity for dynamic control applications is approached using a neural networks technique employing a set of measured samples referring to signals usually available on-board, such as longitudinal and lateral acceleration, steering angle, yaw rate and linear wheel speed. Experiments were run on four professional driving circuits with very different characteristics, and the vehicle longitudinal velocity was estimated with different neural network training policies and validated through comparison with the measurements of the one acquired at the vehicle's center of gravity, provided by an optical Correvit sensor, which serves as the reference (and, therefore, exact) velocity values. The results obtained with the proposed methodology are in good agreement with the reference values in almost all tested conditions, covering both the linear and the nonlinear behavior of the car, proving that artificial neural networks can be efficiently employed onboard, thereby enriching the standard set of control and safety-related electronics. [ABSTRACT FROM AUTHOR]

To realize optimal power distribution between proton exchange membrane fuel cell and battery In fuel cell sightseeing vehicle, an offline extremum seeking-based optimized energy management strategy is proposed in this work. The simulation model of the vehicle and the electric propulsion is developed. The model is based on vehicle dynamics and real motor efficiency as constant DC/DC, motor controllers and transmission efficiency are considered. In order to improve the vehicle economy and component durability, a new improved strategy based on quadratic utility function is proposed. A multi-objective artificial bee colony algorithm is designed, and the optimal parameters of the improved strategy are solved by the algorithm. Simulation results show that compared with thermostat control, the proposed strategy can improve the driving range by 3.98 % and durability by 34 %. In addition, the strategy considers the SOC state and combines the historical output power information of the vehicle and its components. [ABSTRACT FROM AUTHOR]

The reliability of power transmission systems in locomotives directly impacts trains' availability and running safety. The failure of gears, like pitting and chipping on teeth, is a common failure that can affect vehicle dynamics and reduce the system's safety and reliability. Based on the frequent visual inspections, the simultaneous occurrence of pitting and chipping on gear teeth are observed. It is the purpose of this research to investigate these defects and their possible coincidence. The dynamic response of the gear system to the presence of the pitting and chipping damages on one tooth, individually and concurrently, is theoretically and experimentally evaluated and compared. The dynamic interaction between the gear system and other elements, such as the traction motor and wheelset, is based on the operational conditions. The time-variant mesh stiffness is considered the primary internal excitation in the dynamics of the gear system. An analytical method based on the potential energy is used. The defects' coincidence effect on the dynamic response in time and frequency domains is studied. To measure the severity of the defects, some statistical parameters for different failure cases are calculated and compared. As a result, the parameters that exhibit the most sensitivity to the corresponding failure are introduced. [ABSTRACT FROM AUTHOR]

BACKGROUND: Spatial disorientation is defined by incorrect estimation of linear translation, angular rotation, and direction of gravity, posing risk to aviators and astronauts during certain maneuvers. Vestibular organs, located in the inner ear, are a key contributor to the sense of motion. An under-explored cause of spatial disorientation is the difficulty the brain faces in resolving linear accelerations from changes in direction of gravity. In this so-called somatogravic illusion, sustained linear acceleration is misinterpreted by the human controller as tilt, which is implicated in many aviation disasters. Large linear accelerations also occur in spaceflight, and additionally, astronauts may adapt to interpret gravity as linear acceleration. In order to develop countermeasures against these hazards, conditions for, and the extent of, spatial disorientation must first be investigated. OVERVIEW: To better understand this hazard, we are developing closed-loop human-vehicle computational models that combine models of human spatial orientation estimation, human motor control and vehicle dynamics. Spatial orientation estimation is modeled using the well-validated "Observer" model, which reproduces many of the errors that occur in human motion perception. These models are being implemented for scenarios such as a high performance aircraft departing a carrier ship using a catapult launch and performing go-around maneuvers. In the case of carrier takeoffs, these models predict that vestibular misinterpretation of large linear acceleration stimuli as pitch tilts relative to gravity results in rapid, incorrect, and dangerous pitch inputs to the vehicle. The human- estimated and actual pitch angle profiles over time under constant linear acceleration show an overall increase and decrease respectively, resulting in descending altitude, in line with known mishaps. DISCUSSION: To our knowledge, this is the first closed-loop model of somatogravic illusion that includes models of both the human and the aircraft, and it reproduces known behavior. We expect that these models could assist in developing training for pilots and astronauts to prevent associated mishaps, in accident investigations to explain mishaps, and in developing countermeasures, for example enhancing aircraft systems to detect incipient spatial disorientation. Future work will include incorporating the effect of visual input, and implementing vehicle dynamics associated with a lunar landing vehicle. Learning Objectives 1. The audience will be able to understand the role of acceleration in spatial disorientation among pilots and astronauts. 2. The audience will get an insight into closed loop modeling of human-vehicle systems, in how it pertains to vestibular functioning. [ABSTRACT FROM AUTHOR]

The use of virtual sensors in vehicles represents a cost-effective alternative to the installation of physical hardware. In addition to physical models resulting from theoretical modeling, artificial intelligence and machine learning approaches are increasingly used, which incorporate experimental modeling. Due to the resulting black-box characteristics, virtual sensors based on artificial intelligence are not fully reliable, which can have fatal consequences in safety-critical applications. Therefore, a hybrid method is presented that safeguards the reliability of artificial intelligence-based estimations. The application example is the state estimation of the vehicle roll angle. The state estimation is coupled with a central predictive vehicle dynamics control. The implementation and validation is performed by a co-simulation between IPG CarMaker and MATLAB/Simulink. By using the hybrid method, unreliable estimations by the artificial intelligence-based model resulting from erroneous input signals are detected and handled. Thus, a valid and reliable state estimate is available throughout. [ABSTRACT FROM AUTHOR]

In the context of automated and connected vehicle technology, this paper proposes an environment-on-board predictive braking control system, regulating the vehicle velocity to a desired value, in order to enhance path-following performance and vehicle stability when a vehicle is driven on a path where the road friction coefficient changes suddenly on a curve. In this study, we assume that the vehicle enters a wet road from a dry road and moves on to a dry road, and that the forward road surface friction condition can be estimated. In such driving situation, the objective of the vehicle dynamics control system is to improve path-following performance and vehicle stability of automated vehicle, even under abnormal road conditions. To achieve this objective, the predictive braking control is designed to track a safe velocity which is determined based on a simplified linear two-degree-of-freedom bicycle and a 2nd order look-ahead driver model. The effectiveness of this control system is verified using a nonlinear four-degree-of-freedom four-wheel model under various conditions, with varying road friction coefficients and curvatures. Finally, the effectiveness is evaluated using a full vehicle model of the IPG CarMaker, which is similar to an actual vehicle. [ABSTRACT FROM AUTHOR]

The suspension systems are designed to provide good performance in terms of comfort and maneuverability and to satisfy other requirements such as fatigue strength. This study focuses on the leaf springs, a classic mechanism; leaf springs are still being extensively used in several types of vehicles because of their high load capacity and low manufacturing and maintenance costs. Its dynamic behavior assesses stationary nonlinear preload state components to provide considerable added value to this suspension type. This assessment considers the contact condition of the suspension's components and the large deflections and tightening torques observed in the whole assembly. Furthermore, the components of the non-suspended mass subsystems, such as tires, shock absorbers, and stabilizer bars, are characterized according to the simplified models for reducing their computational cost. In addition, a commercial test vehicle is used for simulating the complete system using three-dimensional modeling for describing its most relevant components in terms of their mass and rigid connection. The vehicle is additionally analyzed using multibody system simulations (MBS) coupled with the finite element method (FEM) in an implicit nonlinear transient environment using the ANSYS APDL solver. This dynamic simulation is parameterdriven for obtaining the experimental design and determining the optimal suspension stiffness and damping features required for transporting suitable load sizes. [ABSTRACT FROM AUTHOR]

To illustrate the influence of differential settlement along the lateral direction of subgrade on the dynamic performance of a high-speed vehicle system, based on the vehicle–track coupling dynamic theory and finite-element method, a vehicle–track–subgrade spatial coupling dynamic model considering the lateral mechanical characteristics of the vehicle system is established, and the dynamic performance of the vehicle system under different lateral differential settlement parameters (amplitude/wavelength) of subgrade on one side and both sides and the vehicle speeds are studied. The study reveals the following. The vehicle dynamic response under the lateral differential settlement of subgrade on both sides is generally greater than that under the lateral differential settlement of subgrade on one side, and the difference becomes more obvious with increases in the lateral differential settlement amplitude. However, there is little difference between the two lateral differential settlement modes on the car body lateral acceleration. The wheel/rail vertical force of the left rail (with large settlement amplitude) is greater than that of the right rail (with small settlement amplitude), while the wheel/rail lateral force of the right rail is greater than that of the left rail. The dynamic response of the vehicle system increases with increases in the lateral differential settlement amplitude; the dynamic response of the vehicle system increases noticeably when the amplitude of lateral differential settlement exceeds 25 mm. The lateral differential settlement wavelength is inversely proportional to the dynamic response of the vehicle system, and the wavelength range 5–15 m has the greatest impact on the dynamics of the vehicle system. The vehicle driving speed is directly proportional to the vehicle system dynamic response, and the vehicle system dynamic response increases significantly when the driving speed exceeds 250 km/h. [ABSTRACT FROM AUTHOR]

With the continuous development of road transport of goods, the issue of safety risks related to the movement of trucks and road trains remains an essential element of the overall road safety system. One of the persistent problems is the braking of such kits, especially in emergencies on the road. The work aims to show how typical changes in operating conditions can affect the basic indicators illustrating the safety of braking (effectiveness indicators, stability symptoms). A simulation method was applied for the analysis, which used a relatively simple (quasi-static) model of the tractor-semitrailer set’s rectilinear motion and models of the braking system and the longitudinal forces in the tyre-road surface contact. Calculations were made for the selected truck-trailer set in nominal condition and for several deviations from the nominal state, such as loading the trailer (load value, location of the semi-trailer’s centre of gravity), reduced surface adhesion, and selected faults of the semitrailer braking system. The results were compared for several qualitative and quantitative criteria for the evaluation of braking safety. Attention was drawn to the problem of the forces in the coupling (which determine the possibility of jack-knifing phenomena), the order of axle locking, and the braking distance. The presented results show that the change of operating conditions as above compared to the nominal condition visibly deteriorates the effectiveness of the braking process. The greatest threat, both related to the braking efficiency and the increase in the force in the coupling, is associated with the lack of braking of the semitrailer axle or a significant reduction in its load. The weight and location of the load’s centre of gravity considerably impact braking safety. In addition to the negative impact on the braking distance or increase in the horizontal force in the coupling, it changes the order of locking the axle. ABS reduces the risk associated with braking safety but does not eliminate it. At the same time, it has been shown that using relatively simple calculation tools makes it possible to indicate the risks related to the braking safety of such articulated vehicles.

This paper presents the simulation and calculation-based aspect of constructing a dynamically stable, self-balancing electric monowheel from first principles. It further goes on to formulate a reference model-based adaptive control structure in order to maintain balance as well as the desired output. First, a mathematical model of the nonlinear system analyzes the vehicle dynamics, followed by an appropriate linearization technique. Suitable parameters for real-time vehicle design are calculated based on specific constraints followed by a proper motor selection. Various control methods are tested and implemented on the state-space model of this system. Initially, classical pole placement control is carried out in MATLAB to observe the responses. The LQR control method is also implemented in MATLAB and Simulink, demonstrating the dynamic stability and self-balancing system property. Subsequently, the system considers an extensive range of rider masses and external disturbances by introducing white noise. The parameter estimation of rider position has been implemented using Kalman Filter estimation, followed by developing an LQG controller for the system, in order to mitigate the disturbances caused by factors such as wind. A comparison between LQR and LQG controllers has been conducted. Finally, a reference model-assisted adaptive control structure has been established for the system to account for sudden parameter changes such as rider mass. A reference model stabilizer has been established for the same purpose, and all results have been obtained by running simulations on MATLAB Simulink. [ABSTRACT FROM AUTHOR]

In this article, a proportional integral (PI) fault observer is introduced due to its accuracy and expeditiousness. Considering the time-varying vehicle speed and other uncertain parameters in vehicle dynamics system, a type-2 fuzzy model is proposed to describe the system nonlinearity. Moreover, it could also address the problem of uncertainty in the membership function, which resulted from the parameter uncertainty. In addition, the $\mathcal {H}_{\infty }$ technique is studied to attenuate the effect of disturbance on the estimation performance and a set of linear matrices inequalities are obtained. The particle swarm optimization (PSO) approach is then adopted to find solutions to the PI fault observer. Finally, a simulation test is carried out based on the experimental data, which are collected from an electric vehicle. The simulation results demonstrate the effectiveness of the proposed $\mathcal {H}_{\infty }/PSO$ method. [ABSTRACT FROM AUTHOR]

In this paper the selected phenomena related to motor vehicle’s motion have been considered basing on a computer simulation. The vehicle performed a power-off straight line maneuver with different road conditions being included. All simulations have been performed in the MSC Adams/Car environment based on the available sports two-seater vehicle model, realizing the adopted maneuver at the instant speed of 100km/h. This enabled observation of the selected phenomena along the road long enough to relate them to different aspects of vehicle dynamics research. As for the randomly uneven road, almost similar and almost different profiles have been assumed for the left and right wheels of the vehicle. Additionally, two values of the coefficient determining the maximum amplitude of road irregularities have been selected: 0.3 for lower and 0.9 for higher irregularities, so the road surface conditions along with the flat road have been considered as one of the factors causing disturbances of the motor vehicle motion. Such research seems valuable from the point of view of road traffic safety and vehicle maintenance. This specific example is a presentation of the possible research on vehicle dynamics as well as a potential background for further considerations including different types of vehicles along with almost different road profiles for the left and right wheels of the given vehicle model. A power-off straight maneuver is not performed very often in normal road traffic. However, such test could be valuable when analyzing influence of the selected motor vehicle parameters, such as uneven loading, suspension characteristics, etc. on such maintenance features as stability, steerability and the influence of external disturbances acting on the moving vehicle. Further research provides different maneuvers and different simulation conditions.

This paper focuses on energy management in an ultra-energy efficient vehicle powered by a hydrogen fuel cell with rated power of 1 kW. The vehicle is especially developed for the student competition Shell Eco-marathon in the Urban Concept category. In order to minimize the driving energy consumption a simulation model of the vehicle and the electric propulsion is developed. The model is based on vehicle dynamics and real motor efficiency as constant DC/DC, motor controllers and transmission efficiency were considered. Based on that model five propulsion schemes and driving strategies were evaluated. The fuel cell output parameters were experimentally determined. Then, the driving energy demand and hydrogen consumption was estimated for each of the propulsion schemes. Finally, an experimental study on fuel cell output power and hydrogen consumption was conducted for two propulsion schemes in case of hybrid and non-hybrid power source. In the hybrid propulsion scheme, supercapacitors were used as energy storage as they were charged from the fuel cell with constant current of 10 A. • Driving strategy to minimize energy consumption was determined at given restrictions. • Driving energy is related to acceleration phase when average speed is determined. • Fuel cell degradation requires modified energy management strategy. • Hydrogen consumption was evaluated for hybrid and non-hybrid propulsion. [ABSTRACT FROM AUTHOR]

The mechanism of vehicle dynamics steering bifurcation has almost been confirmed. But the present steering bifurcation mechanism cannot explain the bifurcation phenomena caused by the driving torque. As a result, the vehicle coupled bifurcation analysis of the steering angle and driving torque has not been studied. Based on the five degrees of freedom (5DOF) vehicle system dynamics model with driving torque involved, the vehicle dynamics equilibriums under different driving torque and driving mode were searched by a hybrid method in this paper. The hybrid method combined the real-coded Genetic Algorithm with Quasi-Newton gradient method. According to the definition of static bifurcation of nonlinear systems, the equilibrium bifurcation of 5DOF vehicle system was confirmed. Then, the 5DOF vehicle system model was transformed into autonomous equation with the front wheel steering angle as intermediate variable. From the two aspects of constant steering angle amplitude and constant driving torque, the bifurcation diagrams of different driving mode were calculated. The vehicle coupled bifurcation characteristics of steering angle and driving torque were analyzed. The results show that the values of the driving torque will directly affect the bifurcation characteristics of vehicle dynamics system. The coupled feature of the front wheel steering angle and driving torque effect on vehicle bifurcation is obvious. [ABSTRACT FROM AUTHOR]

Featured Application: This contribution presents a central predictive control of the vehicle dynamics regarding the roll, self-steering and pitch behavior. Considering automated driving, vehicle dynamics control systems are also a crucial aspect. Vehicle dynamics control systems serve as an important influence factor on safety and ride comfort. By reducing the driver's responsibility through partially or fully automated driving functions, the occupants' perception of safety and ride comfort changes. Both aspects are focused even more and have to be enhanced. In general, research on vehicle dynamics control systems is a field that has already been well researched. With regard to the mentioned aspects, however, a central control structure features sufficient potential by exploiting synergies. Furthermore, a predictive mode of operation can contribute to achieve these objectives, since the vehicle can act in a predictive manner instead of merely reacting. Consequently, this contribution presents a central predictive control system by means of a non-linear model-based predictive control algorithm. In this context, roll, self-steering and pitch behavior are considered as control objectives. The active roll stabilization demonstrates an excellent control quality with a root mean squared error of 7.6953 × 10 − 3 rad averaged over both validation maneuvers. Compared to a vehicle utilizing a conventional control approach combined with a skyhook damping, pitching movements are reduced by 19.75 %. Furthermore, an understeering behavior is maintained, which corresponds to the self-steering behavior of the passive vehicle. In general, the central predictive control, thus, increases both ride comfort and safety in a holistic way. [ABSTRACT FROM AUTHOR]

This paper investigates the cluster event-triggered tracking cooperative and formation control for multivehicle systems with nonlinear vehicles dynamics under switching directed communication topologies and safety missions. By employing the cluster event-triggered control strategy, the assumption of continuous feedback control gains and the condition of information exchange limited in a small domain can be relaxed. By constructing an appropriate tracking cooperative condition, a class of cluster event-triggered tracking cooperative control law with an extended magnification region condition is proposed based on bounded parameters and intermittent event samples. When the safety tasks are activated, it is displayed in terms of linear matrix inequalities that the tracking cooperative control for closed-loop multivehicle systems subject to nonlinear vehicles dynamics will be achieved, if the constructed sampling condition and the dwell time constraint of switching communication scenarios can be held. Furthermore, the proposed method is extended to formation control problem for the multivehicle systems. Simulations are presented to demonstrate the effectiveness of the proposed approaches. [ABSTRACT FROM AUTHOR]

Summary: Electric vehicles (EVs) have a limited driving range compared to conventional vehicles. Accurate estimation of EV's range is therefore a significant need to eliminate "range anxiety" that refers to drivers' fear of running out of energy while driving. However, the range estimators used in the currently available EVs are not sufficiently accurate. To overcome this issue, more accurate range estimation techniques are investigated. Nonetheless, an accurate power‐based EV energy consumption model is crucial to obtain a precise range estimation. This paper describes a study on EV energy consumption modelling. For this purpose, EV modelling is carried out using MATLAB/Simulink software based on a real EV in the market, the BMW i3. The EV model includes vehicle powertrain system and longitudinal vehicle dynamics. The powertrain is modelled using efficiency maps of the electric motor and the power electronics' data available for BMW i3. It also includes a transmission and a battery model (ie, Thevenin equivalent circuit model). A driver model is developed as well to control the vehicle's speed and to represent human driver's behaviour. In addition, a regenerative braking strategy, based on a series brake system, is developed to model the behaviour of a real braking controller. Auxiliary devices are also included in the EV model to improve energy consumption estimation accuracy as they can have a significant impact on that. The vehicle model is validated against published energy consumption values that demonstrates a satisfactory level of accuracy with 2% to 6% error between simulation and experimental results for Environmental Protection Agency and NEDC tests. [ABSTRACT FROM AUTHOR]

Vehicle rollover has always been a highly dangerous condition that can cause severe traffic casualties. In this work, a 14-degree-of-freedom vehicle model in MATLAB/Simulink is constructed with the vehicle suspension system dynamics. The validity of the model is verified by comparing with the CarSim model. Then an optimal distribution of damping force strategy with continuous damping control is proposed by combining the traditional lateral load transfer ratio control with optimized equations of suspension damping force. The damping force compensation of the left and right sides is the core of the optimal distribution of damping force strategy. The effectiveness and optimization effect of the optimal distribution of damping force strategy is proved by the simulation results under the fishhook and crosswind tests. The result shows that continuous damping control has evident control effects on vehicle rollover compared with passive suspension. The optimal distribution of the damping force strategy with continuous damping control has a great better performance than traditional continuous damping control, and it provides a certain assistance to vehicle handling stability. [ABSTRACT FROM AUTHOR]