Ride Comfort Research Articles

Driver Assisted Lane Keeping with Conflict Management Using Robust Sliding Mode Controller

Lane-keeping assistance design for road vehicles is a multi-objective design problem that needs to simultaneously maintain lane tracking, ensure driver comfort, provide vehicle stability, and minimize conflict between the driver and the autonomous controller. In this work, a cooperative control strategy is proposed for lane-keeping keeping by integrating driving monitoring, variable level of assistance allocation, and human-in-the-loop control. In the first stage, a time-varying physical driver loading pattern is identified based on a relationship between lateral acceleration, road curvature, and the measured maximum driver torque. Together with the monitored driver state that indicates driver mental loading, an adaptive driver activity function is then formulated that replicates the levels of assistance required for the driver in the next stage. To smoothly transition authority between various modes (from manual to autonomous and vice versa) based on the generated levels of assistance, a novel higher-order sliding mode controller is proposed and closed-loop stability is established. Further, a novel sharing parameter (which is proportional to the torques coming from the driver and from the autonomous controller) is used to minimize the conflict. Experimental results on the SHERPA high-fidelity vehicle simulator show the real-time implementation feasibility. Extensive experimental results provided on the Satory test track show improvement in cooperative driving quality by 9.4%, reduction in steering workload by 86.13%, and reduced conflict by 65.38% when compared with the existing design (no sharing parameter). These results on the cooperative performance highlight the significance of the proposed controller for various road transportation challenges.

Prediction of Ride Comfort of High-Speed Trains Based on Train Seat–Human Body Coupled Dynamics Model

A train seat–human body coupled dynamics model was established to predict the ride comfort of high-speed trains. The train and track and the seat and human body were both coupled in the model. An on-site vibration experiment in a high-speed train was carried out to calibrate each part of the train seat–human body coupled dynamics model. Based on the evaluation method proposed by BS EN 12299:2009, the distribution of ride comfort in the carriage and the effect of seat cushion stiffness and damping on ride comfort were analyzed systematically. The results showed that the seats in the middle of the carriage had the best comfort performance, while those near the side wall and close to the position where the suspension force of the second series was acting were less comfortable. The seat cushion stiffness and damping had great effect on ride comfort.

Adaptive cruise control method based on hierarchical control and multi-objective optimization

Considering the perception of a driver, driving safety, and riding comfort, an adaptive cruise control (ACC) method based on a multi-objective (MO) real-time optimization control algorithm is proposed. The ACC system can be divided into various working modes according to the driver’s perception, as well as the relative state of the host vehicle and the preceding vehicle. To distinguish the driver’s intention in the rapid acceleration, strong deceleration, steady, and larger clearance modes, a fuzzy tool is proposed to solve the problem. To maintain the inter-clearance, velocity, and jerking action in a reasonable region, an MO control algorithm based on model predictive control was used to obtain the optimal control vectors. Moreover, the control vector increment is restricted to suppressing the fluctuation caused by switching among various modes. Simulations were conducted for various scenarios to verify the effectiveness of the ACC method. The simulation results indicated that the driver’s comfort and fuel economy improved by 35.3% and 16.6%, respectively, compared with the linear quadratic algorithm in a complicated driving environment. Various simulation results demonstrated that the MO-ACC controller can reduce fuel consumption while barely sacrificing riding comfort or tracking performance, as compared to the linear quadratic controller.

Revisiting the dynamics of car cabin environment and driver comfort

Revisiting the dynamics of the car cabin environment and its impact on driver comfort is essential, as these concepts have not been explored in recent years. Older methods of assessing driver comfort and cabin environments require elaborate experimental settings and prolonged engagement of study participants, making repeatability difficult. Therefore, this study develops a model for study models the car cabin environment based on temperature, humidity, and CO2 levels using a thermal imager, an air quality device, and open-source temperature and humidity data. This study also determines whether the impact of the cabin thermal environment on driver comfort (skin dryness, eye fatigue, body fatigue, and body heat) can be quantified based on driver perceptions. The study results showed that body fatigue decreased from 4.2 to 2.7 when the average relative humidity is reduced from 37.2% to 24.2%, and the temperature dropped from 41.8°C to 40.0°C. Notably, the impact of air temperature on the cabin thermal environment was 1.8 times stronger than that of the car skin temperature. Cabin temperature was found to be a better predictor of driver (dis)comfort than cabin humidity and CO2 levels. A 10 min exposure to summer heat in the UAE was found to have a significant effect on drivers’ perceptions of body fatigue, body heat, and eye fatigue. Overall, these findings have implications for car cabin ergonomics and future thermal comfort research.

Vehicle ride comfort analysis on sea-crossing bridges under drift ice load

To investigate the ride comfort when vehicles travelling over sea-crossing bridges subjected to ice load in cold sea regions, this study presented a dynamic analysis framework for a vehicle–bridge interaction system under ice-induced vibration. Based on the a real ice load spectrum in Bohai Sea, the ice force process during the interaction between ice and bridge is obtained, and is input into the vehicle-bridge coupling system as an external excitation. This framework was assessed with an interactive system consisting of 6 12-DOF trucks travelling over the pile-supported sea-crossing bridges. Ride comfort of vehicles is investigated under different conditions of vehicle velocity and ice strength and it is evaluated by utilizing newly recommended in the ISO 2631-1(1997). The results show that the vibration of the vehicle will not influence driving comfort of the driver when vehicles traveled over bridges without considering the actions of ice load. However, the evaluation indicator of driving comfort reached a little uncomfortable when vehicles traveled over bridges under ice strength exceeds 1.5 MPa. In addition, the ride comfort analysis based on ISO 2631/1(1985) was also investigated. But the criterion only evaluates the comfort in one direction, and it is disadvantageous for the quantitative evaluation of driving comfort and it may underestimate the overall vibration of vehicles and total evaluation results of vehicle ride comfort.

Cab-Over-Engine truck cabins: A mathematical model for dynamics, driver comfort, and suspension analysis and control

Various cabin designs have been developed for commercial vehicles to meet different driver comfort requirements. Among those configurations, the cab-over-engine (COE) is widely used because of its compact size and good road visibility. Since the engine is assembled underneath the cabin, it is required that the cabin can be entirely tilted forward in order to access the engine for inspection and maintenance. Hence, the forepart of the cabin suspension is designed to connect with the chassis frame through a linkage mechanism. The dynamic modelling of this commonly used configuration was lack of study in the literature, but it is essential for further cabin's dynamic analysis and vibration control. Considering the rapid development of the comfort-oriented cabin suspension, this study introduces a multi-body dynamic modelling approach for the COE cabin with a titling mechanism. The dynamic equations are derived based on the Lagrangian modelling method, which are then implemented in MATLAB/Simulink. Besides, a high-fidelity truck model is developed in ADAMS/Car to study the accuracy of the proposed dynamic model through co-simulation. Meanwhile, a four-point cabin model that has been widely used in past studies is used as the benchmark. The simulation results demonstrate that the proposed cabin dynamic model can accurately estimate the cabin's behaviour in vertical, roll, and pitch directions, which can be used for cabin dynamics, ride comfort, and cabin suspension control studies.

In-vehicle comfort assessment during fore-and-aft random vibrations based on artificial neural networks (ANN)

Driving comfort is one of the important factors for vehicle users. There is a lot of research related to comfort or discomfort in a vehicle but there is still no well-defined way to assess it accurately. In this paper, an assessment of vehicle comfort during fore-and-aft random vibrations was made based on measured and predicted r.m.s. acceleration values. Measured values of r.m.s. accelerations were obtained by laboratory testing while the predicted values of r.m.s. accelerations obtained based on the ANN (Artifical Neural Network) model. 20 male subjects participated in the study. Their different anthropometric characteristics of the body were taken into account. Based on the measured r.m.s. values of acceleration formed ANN model which has ability to predict r.m.s. acceleration values based on measured values. The obtained results showed high accuracy of the model.

Autonomous Braking System Using Linear Actuator

The most frequent cause of vehicle accidents (car, bike, truck, etc.) is the unexpected existence of barriers while driving. An automated braking system will assist and minimize such collisions and save the driver and other people’s lives and have a substantial influence on driver safety and comfort. An autonomous braking system is a complicated mechatronic system that incorporates a front-mounted ultrasonic wave emitter capable of creating and transmitting ultrasonic waves. In addition, a front-mounted ultrasonic receiver is attached to gather ultrasonic wave signals that are reflected. The distance between the impediment and the vehicle is determined by the reflected wave. Then, a microprocessor is utilized to control the vehicle’s speed depending on the detected pulse information, which pushes the brake pedal and applies the vehicle’s brakes extremely hard for safety. For work-energy at surprise condition for velocity 20 km/hr, the braking distance is 17.69 m, and for velocity 50 km/hr, the braking distance is 73.14.

Fuzzy PID control method for damping of electronically controlled air suspension shock absorbers for vehicles

A damping fuzzy proportional-integral-derivative (PID) control method for electronically controlled air suspension shock absorbers was proposed to reduce the RMS values of the body vibration acceleration and improve vehicle ride comfort. Depending on the operating mode of the electronically controlled air suspension shock absorber, a mechanical model of the air suspension shock absorber was established. A fuzzy PID control technology for damping control of the shock absorber is designed by combining a PID control algorithm with the fuzzy control concept. The adaptive expansion factor of the cybernetics domain for the fuzzy PID controller is calculated by considering nonlinear characteristics and time delay to improve the controller’s adaptability. Then, the control parameters are adjusted based on the control deviation and deviation rate parameters. The nonlinear detection platform produced by an enterprise is selected to build an experimental environment for analysis. Simulation results reveal that when the vehicle speed is 30 km h−1, the RMS values of the body vibration acceleration upon applying the proposed method is approximately 0.02 and 0.05 km h−2, respectively, on Class B and C road surfaces. Furthermore, the RMS values of the body vibration acceleration using the proposed method has little fluctuation; when the vehicle speed is 60 km h−1, the RMS values of the body vibration acceleration is 0.022 and 0.028 km h−2, respectively, on Class B and C road surfaces, indicating that the proposed method can effectively reduce the RMS values of the body vibration acceleration and improve rider comfort.

High-Speed Railway Bridge and Pile Foundation: A Review

High-speed railway is trending in developing countries for economic reasons, mobility in the aftermath of COVID-19, and environmental concerns. The high-speed railway operators continuously improve the operational speed to transport more passengers in less time. However, increasing the train loads at high speed might increase the dynamic loads of bridges and affect their pile foundation. A stiffer railway bridge is mandatory for high-speed train safety and passenger riding comfort. However, a flexible bridge is ideal for responding to earthquakes. Thus, these two objectives are conflicting. This review paper provides a bibliometric review aiming to determine the published studies by year and by country, and to visualize different research trends in cluster maps using the VOSviewer software, summarizing the published research for high-speed railway bridges starting from 1964. The review also extracted information from the latest studies by summarizing some essential objectives, useful methodologies, and notable findings that might be applicable to future studies. In conclusion, there is a need for further research to fill the knowledge gap in the study related to the soil–structure interaction phenomenon considering the performance-based seismic design of a high-speed railway bridge on a monopile foundation in the event of lateral spreading due to soil liquefaction.

An Improved Deep Learning-Based Technique for Driver Detection and Driver Assistance in Electric Vehicles with Better Performance

Technology for electric vehicles (EVs) is a developing subject that offers numerous advantages, such as reduced operating costs. Since the goal of EVs has always been to have long-lasting batteries, any new hardware might drastically diminish battery life. Errors are common among human beings. Because of that, accidents and fatalities may occur due to drivers’ different behaviors such as sports style and moderation. To advance driver safety, security, and comfort, Advanced Driver Assistance Systems (ADAS) must be personalized. Modern cars have ADAS that relieves the driver of some of the tasks they perform while driving. As a part of this research, a driver identification system based on a deep driver classification model (deep neural network as DNN) with feature reduction techniques (random forest as RF and principal component analysis as PCA) is implemented to help automate and aid in crucial jobs such as the brake system in an efficient manner. Using task models, we simulate a low-cost driver assisted scheme in real time, where various scenarios are explored and the schedulability of tasks is established before implementing them in EV. The new driver assistance scheme has several advantages over the existing options. It lowers the risk of an accident and ensures driver safety. The proposed model (RF-DNN) achieved 97.05% of accuracy and the PCA-DNN model achieved 95.55% of accuracy, whereas the artificial neural network as ANN with PCA and RF achieved nearly 92% of accuracy.

MATLAB Simulation and Analysis of Effect of Stiffness to Damping Ratio and Variable Road Elevations on Vehicular Driving Comfort and Safety

Background and Objective: In this work, it is proposed that the use of variation in Tire Spring Length (Ls (Tire)), Suspension Spring Length (Ls (Suspension)) together with changes in Sprung Mass Acceleration (SMA), all as a function of Suspension Stiffness to Damping Ratio (k:c) and Road Elevation (E), will provide the required indicators to enable vehicle drive strategy and optimize autonomous vehicle automatic selection. Methods: MATLAB simulation is performed using three main k:c ratios (1, 20, 0.27) and three main road elevations (1, 3, 5) to achieve the stated objective of this work. Results: It is shown through this work that there is a relationship between spring length variation for both tire and suspension, road elevation, and sprung mass acceleration, such that driving strategy can be optimized according to road profile and k:c ratio using these parameters and the intersection of points between tire spring length variation and suspension spring length variation as a function of time and road elevation. Criteria are established in this research for the design and operation of driving strategy, such that three points of selection are used to enable either comfort or handling mode driving strategy. Conclusion: The final findings confirmed that for better handling, the Spring Length Variation Ratio (SLVR) should be less than one, with a steady increase in SMA and a minimum number of intersections between the tire spring length variation curve and suspension spring variation length curve as a function of road elevation and time. The presented work suggested through Tables 6 and 7 criteria to enable design for mode switching of autonomous vehicles as a function of road conditions.

A secure cross-layer architecture for reactive routing in vehicle to vehicle (V2V) communications

Vehicular communication is one of the essential technologies for increasing road safety, traffic efficiency, and comfort for pedestrians and drivers. In this context, the internet of vehicles is an emerging paradigm. However, with advances in vehicular communication, security threats have also emerged. Several vulnerabilities exist in vehicular communications, including Denial of Service (DoS), black hole attacks, and fabrication attacks. A malicious attack alters the packet information in a fabrication attack, causing congestion and high delays in the vehicular network. We propose two algorithms to protect the routing protocols in a vehicle-to-vehicle scenario against several attacks that target confidentiality, authentication, privacy, and integrity. The first algorithm detects the malicious behavior of each vehicle by calculating the percentage of modified destination addresses. If it exceeds a predetermined threshold, this vehicle is classified as malicious. Otherwise, it is a normal vehicle. The second algorithm detects malicious modifications based on the Signal to Interference Ratio (SIR) by monitoring the SIR value, adjusting the distance, altering the power received, and changing the transmitted power value. We performed simulations using the SUMO 0.22 simulator and Network Simulator (NS). The results obtained show an improvement in End-to-End (E2E) delay, Packet Delivery Ratio (PDR), and reduced overhead.

Influence of bushing flexibility and its constitutive behavior on the performance of suspension system

We study the effect of strut top mount bushing flexibility and its constitutive law on the ride comfort performance of a quarter car suspension model. A fractional Kelvin–Voigt model has been employed to capture the viscoelastic behavior of the top mount bushings. To study the effectiveness of the suspension system, we have considered sinusoidal and standard (motion over bumps) road inputs. For the sinusoidal input, the frequency response function for both the traditional and fractional Kelvin–Voigt models has been obtained using the harmonic balance method. However, we have resorted to numerical simulations for the standard base inputs for which a reduced-order system of ODEs has approximated the fractional derivative term. Convergence of the reduced system of ODEs is established by comparing the numerical results for sinusoidal forcing with those obtained analytically. We find that the bushing modeled as a traditional Kelvin–Voigt element increases the response amplitude in the resonance zone, while for higher frequencies, the response reduces. Hence, the inclusion of bushing flexibility is equivalent to decreasing the damping in the suspension. These observations also remain valid for the fractional Kelvin–Voigt model, but the effect is less pronounced than in the traditional model. Ride comfort for standard road profile is studied in terms of performance indices which suggests that a fractional Kelvin–Voigt bushing improves the ride comfort. Accordingly, bushing flexibility with an appropriate constitutive law should be accounted in the design of a suspension system for ride comfort. • Effect of strut top mount bushing (STMB) flexibility on ride comfort is studied. • Fractional Kelvin–Voigt model is employed for the viscoelastic behavior of the STMB. • Studied the suspension system response on sinusoidal and standard road inputs. • Ride comfort has been studied in terms of transmissibility and performance indices. • We find that STMB flexibility improves ride comfort especially during transient loads.

Development of Energy Saving Operation Technology for Punctuality and Ride Comfort by Optimizing the Point of Target Pattern Re-Creation

Development of Energy Saving Operation Technology for Punctuality and Ride Comfort by Optimizing the Point of Target Pattern Re-Creation

Research on Vehicle Longitudinal Control Method Based on Model Predictive Control

In order to improve the safety of autonomous vehicles during driving and the comfort of drivers and passengers, the longitudinal dynamics model of the vehicle is first established. Secondly, the longitudinal motion control strategy is designed considering the influence of vehicle driving safety and driver comfort. Based on this, a longitudinal motion controller based on model predictive control is established. The upper controller uses the model predictive control algorithm to calculate the expected acceleration, and the lower controller uses the vehicle inverse longitudinal dynamics model to convert the expected acceleration calculated by the upper controller into throttle opening and braking pressure. Finally, the effectiveness of the longitudinal motion controller is verified by MATLAB / Simulink under different working conditions. The simulation results show that the longitudinal motion controller designed in this paper improves the comfort of drivers and passengers under the premise of ensuring the safety of vehicles.

Dynamic Response and Riding Comfort Analysis of a Passenger-Train-Bridge System in Urban Rail Transit

To exactly study the riding comfort of passengers in urban rail transit trains, a coupling vibration model, including passengers, train, and bridge is proposed in this paper. According to the Lagrange Equation, the differential equations of motion of each part are derived, which are coupled with each other through displacement and dynamic interaction forces. A corresponding calculation program is compiled by the Fortran language. A representative steel-concrete composite girder bridge on Beijing Metro Line 5 is selected as the research background, the dynamic responses of passengers and train are simulated in detail, and the dynamic response differences between the passenger and carriage are compared. The passengers’ riding comfort is evaluated according to ISO-2631 Standard based on the simulated data. The result shows that passengers in the middle carriages of the train feel better than those in the head and tail ones. While in the same carriage, passengers on the middle seats feel better than those on both ends of it. If only vibration is considered, passengers will feel better in a fully loaded carriage than those with few passengers. The riding comfort of passengers will be gradually reduced with the increase of the train speed.

Ride comfort analysis of high-speed rail vehicle using laminated rubber isolator based secondary suspension

In this paper, a dynamic model with 13 degrees of freedom is developed with the dynamic models of air suspension systems to study the performance of high-speed passenger vehicles’ suspension systems in a deflated state. Sperling's ride index method is used to assess the influence of vibration on ride comfort and quality. This study focuses on the modelling of the air spring with a laminated rubber isolator. Equations for the bounce, pitch, and roll motion of the car's body and bogies have been developed. It has been observed that the shear spring rate of the laminated rubber spring does not depend on the geometry because the shear modulus is not a function of geometry, whereas the compression modulus is strongly affected by the geometry of the design. Therefore, the negative impact due to the vertical irregularities of the track is considered in this study. From the results, it can be concluded that the vehicle should move at a slower speed when the air spring is deflated to maintain passenger comfort.

The Effects of Articulated Buses on Dwell and Running Times

Articulated buses are being operated more frequently on popular bus routes, as they can handle higher passenger loads and increase rider comfort. Dwell and running times associated with articulated buses are expected to be different from regular low-floor buses. We use archived bus operation and passenger information from three heavily-used bus routes operated by the Société de Transport de Montréal, Canada, to measure these differences. Operation of articulated buses yielded to savings in dwell time, especially with high levels of passenger activity and the use of the third door in alighting. These savings were not reflected in running time, due to increases in the time associated with acceleration, deceleration, and merging with traffic. This study gives transit planners and operators important information on the differences in operating environments between regular and articulated buses.

Long-Term Effects of a Kinematic Bikefitting Method on Pain, Comfort, and Fatigue: A Prospective Cohort Study.

Highlights What are the main findings? Pain and comfort levels improved after bikefit and remained stable through 4 months.Even with discrete increase after 3 months, fatigue levels remained significantly lower. What is the implication of the main findings? Ergonomic adjustments through bikefitting improves riding experience for a long period of time, and it can contribute to increase cycling adhesion.With increased riding comfort and reduced pain, participants showed increased fatigue and mileage levels, indicating increased sports practice. The purpose of this study is to analyze the long-term riders’ subjective responses to a standardized bikefitting method on their bicycles. Eighty-six amateur mountain bikers had their riding posture and bicycle components ergonomically adjusted through a 3D kinematic bikefitting method. Validated subjective scales (Feeling, OMNI, and Numerical Rating Pain Scale) were used to assess their overall riding comfort and fatigue along with localized pain for six body parts. Data were collected just before intervention (baseline or pre), immediately after (or post), and 30, 60, 90, and 120 days after the bikefit session. A Student’s t-test comparing before bikefit and after 120 days showed significant (p < 0.05) reduction in localized pain for all six body parts and riding comfort along with a large effect size effect (d = 1.18) for riding comfort. Although initially reduced, fatigue scores gradually increased over the months, showing a high correlation (r = 0.946) with increased monthly training volume. In conclusion, overall riding discomfort and pain were significantly decreased after a standardized kinematic bikefit session even after 120 days post intervention. However, fatigue scores began to rise after 30 days, showing a high correlation with increasing monthly training volume.