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Over the past ten years, autonomous driving has garnered a great deal of interest from both the scientific community and business. Strong technological advancements have made automated driving more practical because human driving abilities seem limited in terms of driving experience, reaction time, and the effectiveness of real‐time decisions. The development of highly autonomous driving algorithms is inextricably tied to planning and changing a vehicle path that must be user‐acceptable, efficient, and collision‐free. Path planning for road vehicles is a difficult problem due to the high speed involved and the requirement to assure passenger safety. Here, a new path‐planning method is developed for both connected and disconnected automatic road vehicles on multilane highways. This paradigm states that the right phrases to describe the objectives of vehicle improvement, passenger comfort, prevention of vehicle‐to‐vehicle collisions and road deviations are included in the objective function. Hunger Games improved Archimedes optimization (HGE‐ARCO) is used to optimize the paths for achieving better‐planned outcomes. At the 100th penetration rate, the HGE‐ARCO scheme reached a top speed of about 99 km/h. The results shows unmistakably that the proposed HGE‐ARCO produces a time of 12.3021 s, which is less than other conventional methods. [ABSTRACT FROM AUTHOR]

During the autonomous navigation of personal mobility vehicles (PMVs) in pedestrian spaces, avoiding collisions with pedestrians walking nearby is necessary. The avoidance paths of PMVs are affected by the behaviors of the pedestrians, which may also affect passenger comfort. Herein, a local path-planning method that considers passenger comfort to realize comfortable pedestrian avoidance during the autonomous navigation of PMVs in pedestrian spaces is proposed. First, the avoidance path and pedestrian behavior parameters affecting passenger comfort are investigated by evaluating passenger comfort in scenarios with different avoidance paths and pedestrian behaviors. Next, the requirements of a pedestrian avoidance method that considers passenger comfort are set based on the parameters affecting passenger comfort. Finally, a novel path-planning method that satisfies the requirements is proposed. The method is shown to generate comfortable paths in pedestrian spaces via a numerical simulation and participant experiment. [ABSTRACT FROM AUTHOR]

In this paper, we present an LMI-based approach for comfort-oriented cruise control of an autonomous vehicle. First, vehicle longitudinal dynamics and a corresponding parameter-dependent state-space representation are explained and discussed. An LMI-based polytopic LQR controller is then designed for the vehicle speed to track the reference value in the presence of noise and disturbances, where the scheduling parameters are functions of the vehicle mass and the speed itself. An appropriate disturbance force compensation term is also included in the designed controller to provide a smoother response. Then we detail how the reference speed is calculated online, using polynomial functions of the given desired comfort level (quantified by the vertical acceleration absorbed by the human body) and of the road type characterized by road roughness. Finally, time-domain simulations illustrate the method's effectiveness. [ABSTRACT FROM AUTHOR]

In this study, the active control of the three-degree-of-freedom quarter-car suspension system passing over the bridge, which can be modeled as an Euler-Bernoulli beam, is studied. The mathematical model of the bridge and the vehicle was determined and the equations of motion were derived using the Lagrangian method. The obtained equations of motion were solved in Matlab using the fourth-order Runge-Kutta method. By giving the wheels two different road profiles along with the oscillations of the bridge beam, the vehicle's handling and passenger comfort are ensured to be optimal by using the classical PID and Sliding mode control (SMC) method. The accuracy of the proposed method in the study was compared with other studies in the literature. The simulation results showed that thanks to the active suspension controllers, the result of the passenger displacement and acceleration values improved significantly compared to the passive one. [ABSTRACT FROM AUTHOR]

In this study, the full car model, which is exposed to a sinusoidal road input, has been examined to ensure the driving safety of the vehicles and the comfort of the passengers. In this context, the full car, including lateral and vertical movements, is modeled with fourteen degrees of freedom. The second-order equations of motion of the modeled vehicle were obtained using the Lagrangian method and reduced to first-order equations of motion using the state-space form. Then, these equations of motion were solved precisely in the time domain using the Euler method in the Matlab environment. To examine the lateral movements and the rotations of the vehicle in the pitch and roll axis, a sine wave with a wavelength of 5 m and an amplitude of 0,1 m was applied to the wheels of the vehicle. In the analysis, the right front wheel is exposed to a sinusoidal road input at t=0 s, while the left front wheel is exposed to a sinusoidal road input after the vehicle moves 2,5 m. Thus, both the pitch and roll motion of the vehicle will be examined in detail. In the study, four different vehicle masses 500 kg, 1000 kg, 2000 kg, and 3000 kg were taken into consideration and the effect of different vehicle masses on passenger and vehicle dynamic behaviors was investigated. In addition, the situation of passing vehicles at variable speeds from the given disruptive road input has also been examined. The maximum dynamic responses of the passenger and the vehicle were examined when the vehicle speed changed from 3 m/s to 50 m/s by 0,1 m/s. In the study, it has been observed that the vehicle mass and certain vehicle speed have effects on the vertical and lateral displacements and accelerations of the passenger and the vehicle. [ABSTRACT FROM AUTHOR]

Speed planning is one of the tasks that a self-driving vehicle carries out. A complete planner should consider and balance passengers comfort, trip time and energy consumption. This paper proposes a computationally efficient global speed planner for autonomous vehicles that explicitly includes comfort as one of the main objectives. In particular, our approach considers the trip time as a user-specified constraint and optimizes a cost function that accounts for both energy consumption and comfort. Since passenger comfort plays a critical role for self driving vehicle, we propose a comfort model that captures different aspects: planar and vertical accelerations and the contribution of different frequency components. We test the algorithm on a realistic case study and we quantify the trade-off between energy consumption and comfort. [ABSTRACT FROM AUTHOR]

• The principle of the existing most unfavorable tunnel length (MUTL) was clarified. • The theory of MUTL for the interior pressure variation were established. • The concepts and calculation methods of MUTL-S and MUTL-L were proposed. • A number of tunnel length calculations were conducted based on the TWS method. When a high-speed subway passes through a tunnel, the external aerodynamic pressure of the train is transmitted into the train interior, which adversely affects the passenger comfort. The effect of tunnel length on the interior pressure variation of the train cannot be ignored. According to previous studies, there is a most unfavorable tunnel length (abbreviated as MUTL in this paper) for the exterior pressure of the train. However, MUTL for the interior pressure variation is still a research gap. In this study, the effect of tunnel length on the interior pressure variation of tunnel and train was investigated using numerical simulation and TWS method. Additionally, the theoretical formula of MUTL based on the internal pressure variation at the head and tail of the train was established and verified using the results of past field measurements and TWS method. The findings indicate that the interior pressure variation with tunnel lengths within a certain time interval is not monotonic. Moreover, there may be two or even more MUTLs, and the MUTL is also be influenced by the dynamic sealing index. MUTL decreases with increasing train speed and increases with increasing number of cars. The research findings of this paper address the research gap in the study of MUTL on the pressure variation inside trains. These findings offer new theoretical guidance for the research of aerodynamic effects in high-speed subway tunnels, and provide a valuable reference engineering design and optimization. [ABSTRACT FROM AUTHOR]

An innovative Computational Fluid Dynamics (CFD) approach, defined as the Forcing Function Method (FFM), is used to simulate Ride Control Systems (RCS) on an Incat Tasmania Wave-Piercing Catamaran vessel in analysis conducted at model scale. This study examines the FFM's capabilities in head sea regular waves using CFD, and considers three ride control scenarios: Bare Hull (BH), Pitch Control (PC), and Non-Linear Pitch Control (NL PC). CFD-predicted vessel motion is compared to experimental data from a 2.5 m Incat Tasmania Wave-Piercing Catamaran model at 2.89 m/s (Fr∼0.6), showing good agreement. Modification in FFM to account for emergence of control surfaces from the water, and time series of lift forces produced by FFM are also discussed. The frequency domain analysis using heave and pitch Response Amplitude Operators (RAOs) showed a good of agreement in motion reduction trends between CFD and experiments, providing a high level of confidence in the FFM predictions. Dimensionless vertical accelerations are calculated along the length of hull using the various control algorithms, showing a considerable reduction in acceleration, especially at the bow. These outcomes demonstrate the novel CFD approach, FFM, that can be used by ship designers for predicting high-speed vessel motion reductions from deployment of RCS, and thereby improving passenger comfort. • The study validates previously proposed Forcing Function Method(FFM) for adding hydrofoils into vessel CFD in regular waves. • Immersed Depth Factor ensure FFM's capability to account lift force when FFM T-foil is emerged/ shallowly immersed in water. • Comparison between experimental results and the study's findings demonstrates a high level of agreement. • FFM shows a reduction in vessel motions (heave and pitch) in both time and frequency due to Ride Control Systems (RCS). • FFM is an efficient tool for researchers and naval architects, enabling prediction of vessels' motion reductions with RCS. [ABSTRACT FROM AUTHOR]

In developing countries where conventional trains are still in use, passengers endure lengthy hours on board. These passengers could opt for air travel, which offers a much shorter duration. Therefore, environmental factors significantly contribute to the overall comfort of passengers and the modal share of railways. In this cross-sectional research, a questionnaire has been developed to quantify passenger evaluations of factors such as light, temperature, noise, and vibrations. An 11-hour journey between Tehran, the capital of Iran, and the second major city is selected, along with two trains (five-star and four-star). Passengers responded to paper questionnaires, and 382 fully completed ones were collected and analyzed. Satisfaction from light was highest while thermal comfort was lowest. A statistically significant difference was observed between the comfort levels of passengers on the two trains. The results also indicated that certain personal or health conditions affect passenger feelings. For example, individuals suffering from low blood pressure tend to feel cold, or those who wear reading glasses are not satisfied with the illumination. Furthermore, older individuals are more sensitive to vibrations, but those traveling with their families are less sensitive to it. The findings of this research can assist in better compartment allocation for passengers and enhance overall passenger satisfaction. [ABSTRACT FROM AUTHOR]

Public transports like the bus and subway inherently experience noise, vibration, and temperature variations that are different from building environment. Each of them can influence passengers' comfort, but little is known about their combined effects, especially how they affect thermal comfort. This paper presents experimental results from a series of human subject tests under different noises, vibrations, and temperatures. 32 subjects' subjective perception and physiological response were collected under three temperatures (22.5, 25.5, 28.5℃), five noise levels (55, 60, 65, 70, 75 dB(A)), and five vibrating accelerations (0, 0.2, 0.4, 0.6, 0.8 m/s2). We also varied the noise and vibration spectrums to simulate the bus and subway environments. In total, 48 195‐min and 192 115‐min laboratory tests were conducted. By using significance tests (paired t tests and two‐way ANOVA tests) and sensitivity analysis (Treed Gaussian Process), the results show that temperature, noise, and vibration exposures can significantly affect subjects' overall satisfaction. More interestingly, high noise and vibration levels can cause warmer thermal sensations. A change in the noise of 20 dB(A) or vibration of 0.6 m/s2 is equivalent to an ambient temperature change of 0.6 °C. We also observed higher heart rates and metabolic heat production at higher levels of noise and vibrating accelerators. Based on the test results, regression models were developed to describe the combined effects of temperature, noise, and vibration on subjects' overall comfort perception and thermal neutral temperature. They can serve as references for the design and operation of public transport environments. [ABSTRACT FROM AUTHOR]

• Comfort of intelligent vehicles will affect passengers' acceptance of intelligent vehicles. • Driving condition prompt systems may improve passengers' subjective comfort and alleviate motion sickness. • When the vehicle's future driving information is obtained, the degree of passenger posture instability is reduced. The main trend in the development of intelligent vehicles has been on ensuring comfort, safety, efficiency, and environmental sustainability. However, current research focuses primarily on the safety and energy saving of intelligent vehicles, and a comfortable driving experience through a human–machine interaction system has not been sufficiently investigated. This study used a high-fidelity 6-degree-of-freedom driving simulator to evaluate the impact of an independently-designed vehicle driving condition prompt (DCP) systems on subjective passenger comfort and motion sickness. The experiment showed that when future driving information is obtained through the vehicle DCP systems, the passengers' subjective comfort is improved, motion sickness is alleviated, and the degree of passenger posture instability is reduced. These conclusions contribute toward improving the comfort of autonomous vehicles and providing a reference for the future design of human–machine interaction systems for intelligent vehicles. [ABSTRACT FROM AUTHOR]

Bus bunching is of particular concern and undesirable for both operators and passengers in high-frequency transit. In contrast to existing control methods, this paper proposes a novel control policy, namely, providing real-time bus crowding information (BCI) for passengers. It is believed that passengers would spontaneously distribute more evenly among buses and help to prevent bus bunching with the provision of BCI accompanying arrival time information due to the following mechanism. A proportion of passengers would be likely to wait a few more minutes for the next bus when the current bus is crowded and the next bus is more comfortable, and the boarding times of these passengers would make the next bus dwell longer and increase its headway from the previous bus. We formulate bus motion models incorporating passenger boarding choice under BCI to realize the policy in simulation experiments. The results demonstrate that the policy can reduce operation instability by approximately 20% in terms of bus headway and single-trip time. In addition, this policy can significantly reduce the in-vehicle crowdedness experienced by passengers by up to 25% at the cost of small increases in the mean journey time in some cases. The simulation experiments on a holding-controlled route also indicate that the proposed policy is able to coordinate with holding well. A sensitivity analysis further confirms that the policy's performance is robust even if the passengers have low inclinations to choose the next bus. The policy of providing BCI in this paper is especially effective for bus routes with high passenger demand and may have great application potential in practice. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to investigate the passenger comfort changes due to the wake turbulence impact from the formation flight (FF) leading aircraft, which can be a showstopper for the real application of FF to airliners. Design/methodology/approach: Taking advantage of the overall aircraft design and optimization framework, as well as the module for FF assessment, the comfort level has been quantified for aircraft in solo flight and in FF according to ISO 2631–1 specifications concerning vibration total value. Findings: The results showed that atmospheric turbulence intensity is the dominant factor in determining the passenger ride quality in comparison to the impact of formation wake flow. According to the preliminary results of this study, passengers seated away from the aircraft mass center encounter larger discomfort. In comparison to mass center, seats away from mass center also experience slightly stronger discomfort due to FF. The current simulation results show that FF is feasible without remarkably degrading passenger comfort level, which agrees well with the flight test results. Practical implications: As passenger comfort is crucial for civil transport application of FF, the study carried out within this manuscript can give a preliminary indication to the showstopper of FF real-world application. Originality/value: The proposed strategy can provide quantitative values for judging the possible drawbacks of FF, i.e. passenger comfort issues as mentioned in the literature. On the other hand, the aircraft level study based on reliable data and methods can give important insight for this interesting topic and further help the real-world application of FF for commercial aircraft. In addition, it can serve as preliminary studies for further design and operation modifications for aircraft in FF. [ABSTRACT FROM AUTHOR]

In this study, we proposed an autonomous motion planning method for improving passenger comfort while ensuring safety, particularly with respect to mobility scooters used by elderly people. We proposed a trajectory planner for restricting vehicle behaviors with large accelerations and jerks by selecting a safe trajectory from a set of preset trajectories. Then, based on this trajectory planner, we developed an autonomous motion planning method with four different driving modes, and evaluated the effectiveness of the method through a numerical simulation. The simulation results demonstrated that the proposed method increased comfort without compromising on safety. [ABSTRACT FROM AUTHOR]

• 46% of car passengers report some level of carsickness in the past five years. • Including childhood experiences, this rate increases to 59%. • The highest incidence was reported in China, the lowest in Germany. • Incidence differs consistently by age and gender (female > male; young > old). • Main modulating factors are driving dynamics, visual activities, low air quality. About two in three people have experienced carsickness at some point in their life (Reason & Brand, 1975). Little is known about current numbers of sufferers, cultural differences, or which modulating factors are being perceived as most relevant. Therefore, given a global increase of interest in carsickness driven by the development of automated vehicles, this survey intended to assess the status quo of carsickness in different parts of the world. We conducted an online survey with N = 4,479 participants in Brazil, China, Germany, UK and USA. 46% of participants indicated they had experienced some degree of carsickness in the past five years as a passenger in a car. When including childhood experiences, this rate increased to 59%, comparable to the 1975 findings by Reason and Brand. The highest and lowest incidence of carsickness was reported in China and Germany, respectively. In all countries, men and older participants reported a lower incidence of carsickness as compared to females and younger participants. The main modulating factors were found to be driving dynamics, visual activities, and low air quality. This study showed that carsickness still affects about 2/3 of passengers and discusses how its occurrence relates to in-transit activities and other modes of transport. The research provides a sound basis to further study how carsickness develops and to investigate countermeasures to potentially reduce it. [ABSTRACT FROM AUTHOR]

In this paper, the mechanical admittance approach is developed to control a 6 DOF aircraft landing gear. The objective of the control system is improving both passenger comfort (PC) and aircraft handling (AH) which are considered as two important criteria in the evaluation of landing gear systems. A 6 DOF vibrational model and state-space equations are proposed for the system. Then, a control system that is comprised of two loops is proposed. The outer loop is designed for generating a suitable trajectory for body displacement subjected to the tire force. In fact, variable admittance control is used for regulating the dynamical behavior of the system. The other loop is a displacement control loop that used a PD controller to track the generated trajectory. The proposed control system and passive system are both simulated in MATLAB software and the results are compared. The results indicate the effectiveness of the control system in promoting both comfort and handling. [ABSTRACT FROM AUTHOR]

Rail vehicles negotiating curves or in crosswinds are subjected to high lateral forces which provoke high displacements of the lateral suspension. As these displacements need to be limited due to gauging restrictions these forces cause the lateral suspension to reach the bumpstops and consequently the passenger comfort is significantly jeopardized. The paper presents the design of a pneumatic system that allows limiting the lateral displacement during curve negotiation (hold-off device). It describes the different phases of the design process starting from the definition of requirements to be fulfilled. The main components and the effect of their characteristics on the overall performance of the centring system are studied, and completed with an experimental analysis of the centring system. Finally, the described methodology is applied to a typical high speed rail vehicle. The results prove that the concept of a centring system which uses the same technology and components that are used in rail vehicles for the pneumatic height control system of secondary suspensions is possible. This fact is particularly interesting as the market offers this kind of components and has proven their reliability during many hours of service therefore the new hold-off system will be based on in-service validated components. [ABSTRACT FROM AUTHOR]

Predictive cruise control concerns designing controllers for autonomous vehicles using the broadcasted information from the traffic lights such that the idle time around the intersection can be reduced. This study proposes a novel adaptive optimal control approach based on reinforcement learning to solve the predictive cruise control problem of a platoon of connected and autonomous vehicles. First, the reference velocity is determined for each autonomous vehicle in the platoon. Second, a data‐driven adaptive optimal control algorithm is developed to estimate the gains of the desired distributed optimal controllers without the exact knowledge of system dynamics. The obtained controller is able to regulate the headway, velocity, and acceleration of each vehicle in a suboptimal sense. The goal of trip time reduction is achieved without compromising vehicle safety and passenger comfort. Numerical simulations are presented to validate the efficacy of the proposed methodology. [ABSTRACT FROM AUTHOR]

With the ever‐increasing speed of trains, the passenger comfort, and the desired trajectory tracking play an important role in the design of automatic train operation. As the speed increases, the train experiences uncertainties, non‐linearities, unknown disturbances and so on, due to the interaction among track‐environment‐disturbance‐longitudinal train dynamics. Much attention has been drawn to design a suitable control scheme which can improve both longitudinal dynamic performance and operational robustness in view of automatic train operation. In this context, the authors propose a novel composite sliding mode control scheme with model reference adaptation scheme. The sliding surface of the composite control scheme is considered as a two‐layer sliding surface to emulate the coupled vehicle dynamics. To derive the adaptive controller gains mathematically, the model reference adaptation framework is chosen that also helps to demonstrate the stability and the convergence using Lyapunov criterion. The effectiveness of the proposed composite algorithm is being tested by tracking a linear time‐invariant stable reference model in the simulation under different environmental disturbances such as side wind, wet rail and model parameter uncertainties. The proposed scheme is found to improve passenger comfort with a least tracking error. [ABSTRACT FROM AUTHOR]

Sitting still for extended periods of time can lead to physical discomfort and even serious health risks. Due to safety regulations, reducing passenger' sitting time in aircrafts is not feasible. This paper presents the results of a laboratory study, in where an interactive airplane seat was compared with a current economy class seat. Participants used both seats for 3.5 h, and performed significantly more in-seat movements when using the interactive seating system. Furthermore, this interactive seat predominantly lead to significantly better comfort experiences and reduced discomfort experiences, however no significant differences have been found in self-reported localized musculoskeletal discomfort. Passengers indicated that they would prefer this interactive seat over a standard aircraft seat. [ABSTRACT FROM AUTHOR]

Enhancing passenger comfort in an air cabin environment is uniquely challenging. Air travel offers a restrictive passenger experience in terms of available space and the ability to change one’s position or journey. The first step to designing experiences for comfort is to take a broader view of the factors which influence in-flight comfort. While many studies have considered the design and services of aircrafts and airlines, this review focuses on the passenger and the internal and external factors which can affect their comfort. We present a descriptive model of comfort that comprises factors such as individual characteristics, personal travel context and interaction with others. This model could be used to develop an improved aircraft passenger experience. [ABSTRACT FROM PUBLISHER]

An integrated vehicle-biodynamic model is developed in this article by using multi-domain energy domain bond graph model simulation and multi-body simulation software ADAMS VI-Rail. These models are specifically used to evaluate passenger ride comfort in a railway vehicle where vertical and lateral excitations at the wheels arise out of the track irregularities. In the bond graph model, the carbody of the railway vehicle is treated as an Euler-Bernoulli beam and its first five modes are included in the model. Thereafter, a detailed model of the railway vehicle is created in ADAMS VI-Rail. The International Organization for Standardization (ISO) 2631 specification is used to determine the passenger comfort for different travel durations and track irregularities. [ABSTRACT FROM AUTHOR]

As a high-speed train passes through a tunnel, the intense aerodynamic pressure wave outside the train penetrates into the passenger compartments, changing the pressure environment inside the train and causing discomfort to passengers. This phenomenon varies enormously among tunnels of different lengths. To evaluate the real influence of tunnel length on the interior pressure environment of the carriages and ensure passenger comfort, field measurements were conducted on a CRH2A train operating on the Hefei-Wuhan rail line in China; twelve tunnels with lengths ranging from 72 to 10766 m were investigated. Pressure sensors were deployed along the outside and inside train surfaces to investigate the variations in interior pressure with the exterior pressure environment. The results show that the interior pressure curve over time in a short tunnel has a single-trough form, very different from that in a long tunnel. The total variation of interior pressure increases monotonically with tunnel length from 72 to 10766 m, whereas the maximum pressure variation within a 3 s period occurs in the 1080 m tunnel; the variation within a 1 s period is not significantly affected by the tunnel length for tunnel lengths greater than 556 m. There is a delay in the 1 s interior pressure variation in response to an exterior pressure change; this delay is independent of the tunnel length and is approximately 1.2 s in this test. It is found that the reason for passengers’ ear discomfort in very long tunnels, which is mainly an effect of excessive changes in pressure over a long period of time, could be different from that in long or short tunnels. [ABSTRACT FROM AUTHOR]

As the annual air passenger traffic in India is increasing steeply (13.52 million in 2012 compared to 11.02 million in 2010), an environmental impact assessment on important cities connected by air is becoming increasingly indispensable. This study proposes an innovative screening method that uses a modified Environmental Vulnerability Index (EVI). This modified EVI calculator includes aviation-related parameters and can be used to assess the environmental vulnerabilities of political states and cities, in addition to countries as is being already done. This study also suggests the need to include aspects of human comfort in the screening process through the use of state-of-the-art computational fluid dynamical software and large eddy simulations which can be used to estimate forces experienced by aircraft of different sizes during in-flight turbulence for various weather conditions. A comparative analysis is presented on how changing the size of the aircraft operating in a particular route between the cities of Chennai and Bengaluru has better implications on both passenger comfort and the environment. It is observed that if commercial airlines incorporated fewer medium-sized aircraft, there would be a significant reduction in the environmental vulnerability of the two connected cities. [ABSTRACT FROM AUTHOR]

This paper describes a novel manoeuvre planning method to attenuate disturbances acting on occupants of autonomous cars as a result of driving behaviour. New research findings suggested that the passengers in autonomous cars might be more prone to motion sickness and thus overall discomfort. The proposed approach is based on a recently developed novel continuous B-spline path smoothing algorithm for car-like steered robots. Two algorithms are designed for urban driving scenarios and steering between two predefined poses. The resulting paths avoid abrupt changes in steering and longitudinal velocity, by maintaining curvature and its high order continuity. We show that this lead to reduced high frequency disturbances in steering and resulting load disturbances on passengers. The presented novel B-spline manoeuvres outperform other planning methods by reducing lateral acceleration and yaw disturbances. New approach was verified by rigorous simulations, numerical and field experimentation. Tests were repeated for a number of different paths and velocities. The reported results are the first spline based parameterisation methods practically applied for autonomous cars planning and re-planning, then validated using both noisy actuation simulations and field experiments. [ABSTRACT FROM AUTHOR]

Due to the huge difference between outdoor and indoor temperatures during the winter, subway riders inevitably feel thermal discomfort entering and exiting the air-conditioned station interiors and trains. This paper attempts to identify the thermal sensation response resulted from the lagging effect of the transient thermal conditions in a subway station, which consist of "cold-neutral-warm" and "warm-neutral-cold" phases. The results show that the transient variation in ambient temperature causes abrupt sensation responses and affects thermal sensation vote (TSV). Based on multiple conditions and effective temperature difference, the author examines the temporal TSV variations in both the hot transition and cold transition, and calculates the exact values by the respective equations. Moreover, the thermal sensation expectation is used to represent the thermal sensation of unidirectional or bidirectional passenger flows moving across different sections in the transitional space, and is calculated based on the TSV value in unidirectional or bidirectional passenger flows. The findings shed new light on the optimization of subway operation mode. [ABSTRACT FROM AUTHOR]

This study details an efficient fuzzy logic controller (FLC) to improve the performance of active automotive suspension system. A comparison between passive and FLC active suspensions is performed. A mathematical model of automotive active suspension has six degrees of freedom and two input forces generated by two separate actuators are solved using Matlab Simulink. In order to evaluate the effectiveness of the proposed controller under random road disturbance, several performance criteria are assessed based on the dynamic response of the half automotive suspension system. Simulation results of the active suspension system based on the fuzzy logic clearly have been provided to illustrate the effectiveness of the FLC under different road conditions and confirmed that fuzzy logic is very effective for enhancing ride comfort and stability of the vehicle. [ABSTRACT FROM AUTHOR]

This paper reviews, synthesises and benchmarks new understandings relating to railway vibrations. Firstly, the effect of vibrations on passenger comfort is evaluated, followed by its effect on track performance. Then ground-borne vibration is discussed along with its effect on the structural response of buildings near railway lines. There is discussion of the most suitable mathematical and numerical modelling strategies for railway vibration simulation, along with mitigation strategies. Regarding ground borne vibration, structural amplification is discussed and how vibration mitigation strategies can be implemented. There is also a focus on determining how ‘critical velocity’ and ‘track critical velocity’ are evaluated – with the aim of providing clear design guidelines related to Rayleigh wave velocity. To aid this, conventional site investigation data is reviewed and related to critical velocity calculations. The aim is to provide new thinking on how to predict critical velocity from readily available conventional site investigation data. [ABSTRACT FROM AUTHOR]

New technologies have led to an increasingly sedentary lifestyle. Sedentary behaviour is characterised by physical inactivity and is associated with several health risks. This excessive sitting does not only take place in the office or at home, but also during daily commute. Therefore, BMW AG developed an active seating system for the back seat of a car, consisting of sensors in the back rest that register upper body movements of the passenger, with which the passenger controls a game. This study evaluated three different aspects of active seating compared to other tasks (reading, working on laptop, and gaming on tablet). First, discomfort and comfort perception were measured in a 30-minute driving test. Discomfort was very low for all activities and participants felt significantly more challenged, more fit and more refreshed during active seating. Second, heart rate was measured, indicating a light intensity, but nevertheless non-sedentary, activity. Third, average and variability in activity of six postural muscles was measured by electromyography (EMG), showing a higher muscle activity and higher muscle variability for active seating compared to other activities. Active seating might stimulate movements, thereby increasing comfort and well-being. [ABSTRACT FROM AUTHOR]

Vehicles have come to be regarded as another important indoor environment where people spend a significant amount of time. Along with the accelerated development of self-driving vehicles, more attention has been focused on optimizing the thermal comfort of vehicle users. Compared with buildings, vehicles have a non-uniform indoor environment that dynamically changes under the influence of solar radiation and the season of the year. Considering the various environmental factors that significantly impact the indoor condition of a vehicle, it is very challenging to estimate the thermal comfort of a vehicle user, especially when the vehicle is outdoors. Many comfort models have been developed based on subject experiments conducted using vehicles placed in climatic chambers. However, because such laboratory experiments consider only very limited conditions, a dynamic scene that simulates the actual situation of vehicle users under real driving conditions cannot be implemented. To address this issue, the present study utilized long-term outdoor experiments. Based on the data acquired from the experiments, we derived equations for predicting the overall thermal sensation (OTS) of a female vehicle user under both transient and stable conditions. The field experiments were conducted over three seasons and considered a total of 80 female subjects of ages 20–30 years. All the experiments were performed using an experimental vehicle on the rooftop of a seven-story building, where the sunlight was not shielded. The environmental conditions (air temperature, relative humidity, solar radiation, and air velocity) inside and outside the vehicle were measured. The psychological and physiological responses of the subjects during the experiments were also recorded. The physiological responses consisted of the skin temperature at 16 local body sites, while the psychological responses consisted of the local and overall thermal sensation and comfort. The data of 60 randomly selected subjects of the experiments were used to derive optimal multiple regression equations for predicting the OTS of a female vehicle user, while the data of the other 20 subjects were used to validate the proposed equations. The two derived equations of the OTS prediction model for both non-uniform and uniform state of a vehicle consist of simple and straightforward environmental indicators such as outdoor and indoor air temperature, the difference between the outdoor and indoor air temperature, and the solar radiation. A strong correlation between the actual OTS and predicted OTS from the equations were found, showing the feasibility of the developed OTS prediction model. [ABSTRACT FROM AUTHOR]

Abstract: Pressure variations on a train predominantly occur while trains are passing through tunnels. These aerodynamic effects may give rise to aural discomfort in railway passengers. We conducted a field study on the high speed railway track Cologne-Frankfurt/Main as well as a simulation study in our pressure chamber TITAN (DLR-Institute of Aerospace Medicine) with 31 subjects (mean age = 37.7, SD = 12.7; 51.6% male) to investigate pressure comfort for passengers. Continuous assessments of pressure events using sliders and retrospective assessments were acquired. Pressure variations were mostly tolerated. A comparison of field and laboratory setting revealed high congruency of continuous as well as retrospective assessments. A generalized estimating equation model identified pressure change attributes contributing to passengers'' discomfort. Beside attributes of instantaneous pressure changes (e.g. high amplitudes, short durations), pressure events of the recent past significantly influenced current discomfort. Design engineers may use these findings to improve train and tunnel design. [Copyright &y& Elsevier]

Abstract: The objective of this research is to develop a human (passenger/crew) comfort model to establish the relationship between the indoor living conditions and the motions of a vessel, with the main objective of being able to provide better insight and understanding of the factors that can make a human more comfortable onboard a vessel during her operation. In order to do this, a new passenger comfort index (PCI) is developed by using a Sugeno type fuzzy inference system which takes into account seven variables which are motion sickness, air temperature, mean radiant temperature, relative humidity, air velocity, activity level of passengers and their clothing insulation. The PCI is calculated implicitly as the outcome of linguistic rules which are expressed as in the form of if-then clauses. Validation and operational scenarios are performed and discussed to show the applicability of the proposed index. The proposed methodology can be used as a human comfort assessment tool during ship design stage as well as a real-time comfort evaluation of human/passengers to help ship personnel onboard a passenger vessel during her voyage. [Copyright &y& Elsevier]

This paper investigates the possibility of improving the performance of railway vehicle suspensions by incorporating a newly developed mechanical device known as the inerter. A comparative study of several low-complexity passive suspension layouts is made. Improved performance for the lateral and vertical ride comfort, as well as lateral body movement when curving are demonstrated in comparison with the conventional suspension layout. The constraints imposed are to maintain the same level of other performance metrics. The calculations and optimisations are based on linearised plan-view and side-view high-speed train mathematical models. [ABSTRACT FROM AUTHOR]

This paper discusses the use of inerters to improve the stability and performance of a full-train system. First, we construct a 28 degree-of-freedom train model in AutoSim, and obtain a linearised model for analysis in Matlab. Then, the benefits of inerters are investigated by the critical speed, settling time and passenger comfort. In addition, we apply a new mechatronic network for further performance improvement, and synthesise the optimal electrical circuit for experimental verification. From the results, inerters are shown to be effective in improving the stability and performance of train systems. [ABSTRACT FROM AUTHOR]

This paper investigates the possibility of improving the performance of railway vehicle suspensions by incorporating a newly developed mechanical device known as the inerter. A comparative study of several low-complexity passive suspension layouts is made. Improved performance for the lateral and vertical ride comfort, as well as lateral body movement when curving are demonstrated in comparison with the conventional suspension layout. The constraints imposed are to maintain the same level of other performance metrics. The calculations and optimisations are based on linearised plan-view and side-view high-speed train mathematical models. [ABSTRACT FROM AUTHOR]

This paper details a coupled vertical-lateral 37 degrees of freedom mathematical model of an Indian Railway general sleeper ICF coach is formulated using Lagrangian dynamics. In this analysis, the vertical and lateral irregularities of railway track are incorporated as a random function of time. The simulated results are compared with the experimental data obtained through actual rail vehicle testing. The ride comfort is evaluated incorporating ISO 2631-1 standard. [ABSTRACT FROM AUTHOR]

• Revision and analysis of smartphone applications in railways. • Analysis of comfort ride in track transitions. • Methodology to calculate comfort level with smartphones and tablets. • Methodology to monitor track quality using smartphones/tablets technology. Measurement process in railways is an expensive and difficult task which involves several steps. In some cases, costs can be reduced by using conventional devices such as smartphone and tablet applications. The following paper presents first a complete revision of the use of these devices in track measurements and secondly, it analyses the methodology to measure ride quality and track monitoring by simplifying it and making it more cost-effective. Accelerations were measured inside the train body in a simple and accessible way by using conventional smartphoneś apps. Results showed the feasibility to measure ride comfort, to study the track condition and locate singular points along the track. The proposed methodology tries to determine track monitoring and analyse passenger comfort by using these 'everyday' tools to take measurements in an easier, faster and cheapest way. The case studied showed that the acquired data in a track section can be used not only to model some important parameters of track performance but also to model riding comfort, which can help in the assessment of the track maintenance and ride quality. In addition, an alternative, new and simpler way of evaluating passenger riding comfort through vertical accelerations has been formulated, based on the current regulations and guidelines in Spain. [ABSTRACT FROM AUTHOR]

Experiments were carried out in a three-row, 21-seat section of a simulated aircraft cabin installed in a climate chamber to evaluate the extent to which passengers’ perception of cabin air quality is affected by the operation of a gas-phase adsorption (GPA) purification unit. A total of 68 subjects, divided into four groups of 17 subjects took part in simulated 11-h flights. Each group experienced four conditions in balanced order, defined by two outside air supply rates (2.4 and 3.3 l/s per person), with and without the GPA purification unit installed in the recirculated air system, a total of 2992 subject-hours of exposure. During each flight the subjects completed questionnaires five times to provide subjective assessments of air quality, cabin environment, intensity of symptoms, and thermal comfort. Additionally, the subjects’ visual acuity, finger temperature, skin dryness, and nasal peak flow were measured three times during each flight. Analysis of the subjective assessments showed that operating a GPA unit in the recirculated air provided consistent advantages with no apparent disadvantages. Practical Implications Operating a gas-phase adsorption (GPA) air purifier unit in the recirculated air in a simulated airplane cabin provided a clear and consistent advantage for passengers and crew that became increasingly apparent at longer flight times. This finding indicates that the expense of undertaking duly blinded field trials on revenue flights would be justified. [ABSTRACT FROM AUTHOR]

Simulated 4-h flights were carried out in a realistic model of a three-row, 21-seat section of an aircraft cabin that was reconstructed inside a climate chamber. Twenty-nine female subjects, age 19–27 years, were split into two groups; each group was exposed to four conditions: two levels of ozone (<2 and 60–80 p.p.b.) at two outside air supply rates (2.4 and 4.7 l/s per person). A companion study measured the chemicals present in the cabin air during each of the simulated flights. The subjects completed questionnaires to provide subjective assessments of air quality and symptoms typical of complaints experienced during actual flight. Additionally, the subjects’ visual acuity, nasal peak flow and skin dryness were measured. Based on self-recorded responses after 3¼ h in the simulated aircraft cabin, they judged the air quality and 12 of the symptoms (including eye and nasal irritation, lip and skin dryness, headache, dizziness, mental tension, claustrophobia) to be significantly worse (P<0.05) for the “ozone” condition compared to the “no ozone” condition. The results indicate that ozone and products of ozone-initiated chemistry are contributing to such complaints, and imply previously unappreciated benefits when ozone is removed from the ventilation air supplied to an aircraft cabin.Journal of Exposure Science and Environmental Epidemiology (2008) 18, 272–281; doi:10.1038/sj.jes.7500586; published online 13 June 2007 [ABSTRACT FROM AUTHOR]

A 21-seat section of an aircraft cabin with realistic pollution sources was built inside a climate chamber capable of providing fresh outside air at very low humidity. Maintaining a constant 200 l/s rate of total air supply, i.e. recirculated and make-up air, to the cabin, experiments simulating 7-h transatlantic flights were carried out at four rates of fresh outside air supply – 1.4, 3.3, 4.7, and 9.4 l/s per person (3, 7, 10, and 20 cfm/person) – resulting in humidity levels, ranging from 7% to 28% relative humidity (RH). Four groups of 16–18 subjects acted as passengers and crew and were each exposed to the four simulated flight conditions. During each flight the subjects completed questionnaires three times to provide subjective ratings of air quality and of symptoms commonly experienced during flight. Physiological tests of eye, nose, and skin function were administered twice. Analysis of the subjective assessments showed that increasing RH in the aircraft cabin to 28% RH by reducing outside flow to 1.4 l/s per person did not reduce the intensity of the symptoms that are typical of the aircraft cabin environment. On the contrary, it intensified complaints of headache, dizziness, and claustrophobia, due to the increased level of contaminants. Practical Implications The investigation shows that increasing aircraft cabin humidity by decreasing the ventilation flow rate of fresh outside air would not decrease reports of discomfort made by cabin occupants. [ABSTRACT FROM AUTHOR]

Magnetorheological dampers, which are semi-active devices that use MR fluids to produce controllable forces, can be used as smart actuators to reduce the vibrations of mechanical systems. The advantage of these actuators is the low power input requirements and the high output force they produce. An analytical study is performed in this article to examine the effectiveness of this type of actuator in suppressing the vibrations of a passenger car suspension system. A half-car model including passenger dynamics subjected to road disturbance is used. Two MR dampers attached to the front and back axles are used as actuators. An optimal control scheme is used to control the overall suspension system such that the vibrations of the passenger seats as well as the chassis of the car are greatly reduced or eliminated. The simulation results show that properly controlled MR dampers are effective means for vibration suppression for passenger cars. [ABSTRACT FROM AUTHOR]

Assessing the potential of advanced driver assistance systems requires developing dedicated control algorithms for controlling the longitudinal speed of automated vehicles over time. In this paper, a multiobjective off-line optimal control approach for planning the speed of the following vehicle in adaptive cruise control (ACC) driving is proposed. The implemented method relies on the principle of global optimality fostered by dynamic programming (DP) and aims to minimize propelling energy consumption and enhance passenger comfort. The powertrain model and onboard control system are integrated within the proposed car-following optimization framework. The retained ACC approach ensures that the distance between the following vehicle and the preceding vehicle is always maintained within allowed limits. The flexibility of the proposed method is demonstrated here through ease of implementation on a wide range of powertrain categories, including a conventional vehicle propelled by an internal combustion engine solely, a pure electric vehicle, a parallel P2 hybrid electric vehicle (HEV) and a power-split HEV. Moreover, different driving conditions are considered to prove the effectiveness of the proposed optimization-driven ACC approach. Obtained simulation results suggest that up to 22% energy-saving and 48% passenger comfort improvement might be achieved for the ACC-enabled vehicle compared with the preceding vehicle by implementing the proposed optimization-driven ACC approach. Engineers may adopt the proposed workflow to evaluate corresponding real-time ACC approaches and assess optimal powertrain design solutions for ACC driving. [ABSTRACT FROM AUTHOR]