Vehicle Handling Stability Research Articles

Research on modeling and optimization simulation analysis of micro electric vehicle suspension

Suspension system is one of the key parts of vehicle, the performance of suspension system has great influence on vehicle handling stability and safety. In order to improve the performance of suspension system, the Macpherson suspension of a vehicle is taken as the research object, the suspension model is established by ADAMS/Car, and carried out parallel wheel travel simulation to analyze the key parameters variation of camber angle, toe angle, caster angle, kingpin inclination angle and scrub radius. Simulation results show that camber angle and scrub radius are beyond normal design range and require optimization. Wheel alignment parameters are determined by sensitivity analysis, and optimized by ADAMS/Insight. Then carried out simulation to analyze the performance of optimized suspension system. Results show that optimized suspension system satisfies the requirements of vehicle stability and safety.

Optimization method of vehicle handling stability based on response surface model with D-optimal test design

In order to improve the handling stability of a vehicle, an optimization method of vehicle handling stability based on D-optimal test design was proposed in this paper. The multibody dynamic model was established and verified by experiments. On this basis, a response surface model was established based on D-optimal test design. An improved genetic-particle swarm algorithm was used to optimize the vehicle handling stability. The general evaluation score of vehicle handling stability was taken as the optimization objective. The vehicle structural parameters, tire and spring characteristics were regarded as design variables. The results showed that the multi-body dynamic model was accurate. After optimization, the general evaluation score of vehicle handling stability increased by 8.98 %; the score of the steering returnability and steady static circular test was increased by 20.43 % and 27.31 %, respectively. Then from the sensitivity of the optimization variables to the stability of the vehicle's handling, the rear wheel lateral stiffness has the greatest impact on it, with a sensitivity of 86.9 %; the wheelbase has the smallest impact on it, with a sensitivity of -3.39 %, which can be reduced in future optimization variable to improve design efficiency.

Sliding Mode Switch Control of Adjustable Hydro-Pneumatic Suspension based on Parallel Adaptive Clonal Selection Algorithm

The hydro-pneumatic suspension, as a widely used suspension for heavy vehicles, has been taken seriously by researchers for a long time because it is crucial in terms of handling stability, riding comfort, and driving safety of these vehicles. Most previous studies only discussed the control of ride comfort or vehicle handling stability of the suspension system separately. This article proposes a dynamic switch control strategy which can switch between ride comfort and handling stability controllers under different road surfaces and driving conditions. The load transfer ratio (LTR) is selected as the switch performance index, and it is calculated through a six-degrees-of-freedom (6-DOF) model. The ride comfort and handling stability controller of the hydro-pneumatic suspension are designed based on the sliding mode control theory. The objective functions of parameters optimization of the sliding mode controller (SMC) are obtained by means of analytic hierarchy process (AHP), and then the controller’s parameters are optimized by the parallel adaptive clonal selection algorithm (PACSA). The simulation results based on MATLAB/Simulink show that: (1) the PACSA performs better than a genetic algorithm in terms of the parameters optimization of the SMC; (2) the proposed switch control strategy can simultaneously improve the ride comfort and handling stability under several typical steering maneuvers and various road profiles compared with the conventional SMC-controlled suspension.

Shimmy analysis of steering system with independent suspension based on coupled feedback model

Shimmy of steering system causes the snaking and deteriorates the handling stability and safety of vehicles, which has not been solved effectively for the ambiguity of shimmy characteristic. In order to uncover the mechanism of shimmy, a 5-DOF dynamic model of the steering system with independent suspension is established, and the coupled feedback model of the steering system is further obtained based on the dynamic model. Then the frequency characteristics of feedback are analysed, and the work and damping energy dissipation of each feedback link in a unit period are calculated. Based on the range of natural frequency and unit periodic energy of steering system, the range of wheel shimmy frequency and velocity interval is determined. The analysis results show that the shimmy frequency is the first natural frequency of steering system. The amplitude of wheel shimmy is calculated based on energy conservation, and the energy transfer of steering system is elaborated. The mechanism of shimmy was uncovered based on the energy transfer of coupled feedback system. The theoretical analysis was verified by numerical simulation. The results provide theoretical support for the mechanism research and active control of shimmy.

The optimum matching control and dynamic analysis for air suspension of multi-axle vehicles with anti-roll hydraulically interconnected system

The control of suspension has been extensively studied and practically utilized in numerous fields of the automotive industry. However, few studies have been conducted on the suspension performance of multi-axle vehicles with an anti-roll hydraulically interconnected system control. In order to solve this problem, the present study is focused on the roll-resistance performance and optimum matching of articulated vehicles equipped with anti-roll hydraulic interconnected control suspension. Three hydraulic interconnected control systems for single-axle, dual-axle and tri-axle suspension of semitrailers are firstly modelled and verified in AMESim, and then seven coupling vehicle models are established by co-simulation method in AMESim, MATLAB/Simulink and Trucksim. Dynamic simulation analysis shows that D23 and D123 have great application value as the optimum strategy considering the engineering cost and anti-roll capacity. Subsequently, a fuzzy controller is proposed for the problem of insufficient roll resistance of D23. The results show that designed controller can further effectively improve the handling stability of vehicle.

Interacting multiple model state observer-based coordination control of electro-hydraulic composite electronic stability program

In this paper, an electro-hydraulic electronic stability program composite control method is proposed for electric wheeled vehicles based on interacting multiple model state observer. Hydraulic system model, electric-driving wheel model, 2-degrees-of-freedom vehicle reference model and 7-degrees-of-freedom vehicle model are established at the beginning. The necessary state estimations and calculations are also accomplished utilising interacting multiple model unscented Kalman filter. Then, the proposed upper controller calculates the additional yaw moment by fuzzy sliding mode control, and the lower controller distributes the longitudinal force and additional yaw moment based on the quadratic programming optimisation allocation to improve the vehicle handling stability. Finally, using Simulink and CarSim, a joint simulation test platform is established. The simulation results show that the state observer can estimate the driving state parameters accurately enough under various conditions, and coordination control method mentioned in this paper can significantly improve the electric wheeled vehicle's handling stability under extreme conditions.

Improvement of vehicle stability using a controller based on reinforcement learning

This paper presents a study on the use of reinforcement learning to control the torque vectoring of a small electric racecar aiming to improve vehicle handling and vehicle stability. The reinforcement-learning algorithm used is Neural Fitted Q Iteration, and the sampling of experiences is based on simulations using the software CarMaker. The cost function is based on the position of the states on the phase-plane of sideslip angle and angular velocity. To investigate the maximum ratio of torque distribution that should be set to guarantee stability as well as the effectiveness of the controller inputs in the learning process, two experiments were done (A and B) with different states and possibilities of torque distribution. The controller A is able to improve the vehicle handling and stability with a significant reduction in vehicle sideslip angle. And it also showed that 70% of torque distribution is enough to keep the vehicle stable.

Improvement of vehicle stability using a controller based on reinforcement learning

This paper presents a study on the use of reinforcement learning to control the torque vectoring of a small electric racecar aiming to improve vehicle handling and vehicle stability. The reinforcement-learning algorithm used is Neural Fitted Q Iteration, and the sampling of experiences is based on simulations using the software CarMaker. The cost function is based on the position of the states on the phase-plane of sideslip angle and angular velocity. To investigate the maximum ratio of torque distribution that should be set to guarantee stability as well as the effectiveness of the controller inputs in the learning process, two experiments were done (A and B) with different states and possibilities of torque distribution. The controller A is able to improve the vehicle handling and stability with a significant reduction in vehicle sideslip angle. And it also showed that 70% of torque distribution is enough to keep the vehicle stable.

Path tracking with minimum time of vehicle handling inverse dynamics based on adaptive gauss pseudospectral method

Vehicle driving safety is the urgent key problem to be solved by an independent automobile development project. And it is also the premise and one of the necessary conditions for active vehicle safety. A new technique for path tracking with minimum time of vehicle handling inverse dynamics is proposed in this paper. Based on a new optimal control method – Adaptive Gauss Pseudospectral Method (AGPM), the optimal control for path tracking with minimum time problem was converted into a nonlinear programming problem which met the boundary condition and a series of path constraints including path constraint, state constraint, control constraint. And then the problem was solved using the sequential quadratic programming (SQP). The simulation results showed that the proposed method was not sensitive to the initial value and the optimization efficiency was higher compared with indirect methods and traditional direct methods. When solving the problem of path tracking with minimum time as per this method, boundary constraints and path constraints were well satisfied. The algorithm was not only precise but it could also shorten the evaluation period of vehicle handling stability and could reduce the tremendous cost for real vehicle testing. So the maneuverability of two different vehicles that complete the pylon course slalom test road with minimum time can be evaluated objectively by utilizing the method. The model correctness is verified through a real vehicle test.

Study on Simulation Analysis of Vehicle Handling Stability Based on MATLAB

Vehicle handling stability is an important performance index of vehicle, which directly affects the safety performance of vehicle. Driving speed, tire lateral stiffness, center of mass position, front wheel Angle are important factors affecting vehicle handling stability. This paper analyzes the influence of these four factors on the vehicle handling stability, draws the corresponding curve with Matlab software, and simulates the vehicle handling stability. This study provides a research method for analyzing the influence of driving speed, tire lateral stiffness, center of mass position and front wheel Angle on vehicle maneuvering stability.

Interconnected State Control Method and Simulations of Four-corner Interconnected Air Suspension

The four-corner interconnected air suspension can effectively improve vehicles ride comfort, but the opening of the interconnection will intensify the roll or pitch of the car body, reducing the vehicle handling stability when the vehicles are in the turning, acceleration and deceleration conditions. To solve the above problems, an interconnected state control method is proposed for four-corner interconnected air suspension, the interconnection state of the pipeline is determined by the relationship between the torque produced by the air spring and the roll angles or pitch angles of the car body. The parameters of air spring pressure, car body roll angle and pitch angle are used in the control method to obtain the optimal interconnection state of four interconnected pipelines through control algorithm calculation. Finally, the opening and closing of four interconnected pipeline solenoid valves are controlled. In order to verify the effectiveness of the control method, the MATLAB/Simulink model of four-corner interconnected air suspension is established and simulated.

Research and Optimization of Vehicle Handling Stability Based on Multi - body Dynamics

Based on multi-body dynamics virtual simulation method, the vehicle simulation model is built and the transient response characteristics of the vehicle are analysed under the steering angle step input. According to the results, the improving method is given. The optimization and stiffness test of tuning bushing are carried out, and the better bushing stiffness is obtained. The vehicle steering transient response performance improvement effect is obvious. This method provides theoretical reference for structural engineers.

A steering control simulation system for vehicle simulator

In order to study man-machine engineering problem with vehicle simulator, a steering control simulation system was designed. The mechanical structure and working process of this system was illustrated. The system model was build, according to low frequency working condition, parameter identification experiment was made to obtain amplitude ratio and phase lag in different frequency. Least square method was used to fit transfer function and frequency response was analyzed. Aligning and steering experiment was set to test this system. The result indicates that steering wheel aligns to zero position in 1 s without oscillation, aligning performance is good and meets the needs of vehicle simulator, torque measured by this system and simulated from transfer function shows great consistency, the transfer function can be applied to control this system. Setting different resistance torque can make research on driver comfort and vehicle handling stability, besides provide some help for power steering, steer-by-wire system design.

Torque Coordinated Control of Four In-Wheel Motor Independent-Drive Vehicles With Consideration of the Safety and Economy

How to reasonably coordinate and control the torque of four wheels to enhance vehicle performance is an important research problem of the four in-wheel-motor independent-drive electric vehicle (4MIDEV). In this paper, a coordinated hierarchical control strategy for the dynamic wheel torque of 4MIDEV steering is proposed, which considers both safety and energy-saving performance. The innovation of this paper lies in two new valuable algorithms in the top and bottom level controller, respectively. Besides the optimal control method on the basis of the 2-degree of freedom (DoF) ideal model in the top level controller, a novel model predictive control method based on the 7-DoF dynamic model is put forward to obtain two virtual generalized forces required during vehicle driving. In the bottom level controller, a novel optimal allocation (OA) algorithm is brought forward to improve the safety and energy-saving performance. The tire stability margin and the electric power of driving system balancing the driving energy consumption and regenerative braking energy recovery are considered in the quadratic objective function of OA algorithm at the same time. Carsim-Simulink joint simulation results under open-loop and closed-loop steering conditions illustrate that, compared with the 2-DoF LQR control method, the 7-DoF MPC method could effectively improve vehicle handling stability and safety. The bottom optimal allocation algorithm can not only improve the vehicle handling stability, but also make the driving system more energy-saving.

Collaborative model analysis on ride comfort and handling stability

For considering the connection and mutual influences between ride comfort and handing stability of a vehicle, a collaborative study on the two performances is carried out in the paper. Firstly based on the UniTire model and combined with filtered white noise models for front and real road excitations, 4-DOF plane model for ride comfort and 2-DOF plane model for handling stability, a collaborative model for ride comfort and handing stability is built by adopting state equations, and a collaborative simulation algorithm for them is also proposed. Then, a collaborative simulation on the ride comfort and handing stability of a vehicle under common road grade and speed conditions is conducted. The results show that the ride comfort and handling stability of a vehicle can be simulated simultaneously by using the collaborative model. The handling stability parameters simulated with the linear UniTire model are larger than those simulated with the nonlinear UniTire model, indicating that it is obviously conservative to study vehicle handling stability with the linear UniTire model.

Structural Parameter Optimization Design of Torsion Beam Semi-Independent Suspension Based on Multi-Island Genetic Algorithm

In order to reduce the variation of suspension parameters during wheel runout, andimprove the handling stability of the whole vehicle, a method for optimal design of Torsional beamsuspension structural parameters based on Multi-island genetic algorithm is proposed. Study on theMacpherson Front suspension of a car, based on the Euler's four-element method of multi-bodydynamics and the spatial analytic geometric transformation formula, the mathematical model ofTorsional beam suspension is derived in this paper, the reliability of the mathematical model isverified by the simulation analysis of the corresponding Adams model. On this basis, the degree ofsuspension performance affected by structure parameters is obtained by Sensitivity analysis. Finally,the optimization of suspension performance is realized by modifying the parameters by usingMulti-island genetic algorithm, which plays an important role in the stability and safety of thewhole vehicle.

Research on the handling stability of four-wheel steering vehicle

Now days, people have higher and higher requirements on automobile performance. As an important performance of a vehicle, the handling stability not only affects the driver’s driving experience, but also relates to the safety of the occupants. In order to improve the handling stability of vehicles, a simulation of the four-wheel-steering system in the linear range based on the time domain was conducted in this paper. Sideslip angle and yaw rate were taken as control targets. Proportional feedback control and PID control were integrated in the control system. The comparison of the front-wheel-steering system and the four-wheel-steering system indicated that the four-wheel-steering system had obvious effect on improving the handling stability of the vehicle.

Improving Handling Stability Performance of Four-Wheel Steering Vehicle Based on the H2/H∞ Robust Control

Considering the demand for vehicle stability control and the existence of uncertainties in the four-wheel steering (4WS) system, the mixed H2/H∞ robust control methodology of the 4WS system is proposed. Firstly, the linear 2DOF vehicle model, the nonlinear 8DOF vehicle model, the driver model, and the rear wheel electrohydraulic system model were constructed. Secondly, based on the yaw rate tracking strategy, the mixed H2/H∞ controller was designed with the optimized weighting functions to guarantee system performance, robustness, and the robust stability of the 4WS vehicle stability control system. The H∞ method was applied to minimize the effects of modeling uncertainties, sensor noise, and external disturbances on the system outputs, and the H2 method was used to ensure system performance. Finally, numerical simulations based on Matlab/Simulink and hardware-in-the-loop experiments were performed with the proposed control strategy to identify its performance. The simulation and experimental results indicate that the handling stability of the 4WS vehicle is improved by the H2/H∞ controller and that the 4WS system with the H2/H∞ controller has better handling stability and robustness than those of the H∞ controller and the proportional controller.

A direct yaw moment controller for a four in-wheel motor drive electric vehicle using adaptive sliding mode control

In this paper, a direct yaw moment control algorithm is designed such that the corrective yaw moment is generated through direct control of driving and braking torques of four in-wheel brushless direct current motors located at the empty space of vehicle wheels. The proposed control system consists of a higher-level controller and a lower-level controller. In the upper level of proposed controller, a PID controller is designed to keep longitudinal velocity constant in manoeuvres. In addition, due to probable modelling error and parametric uncertainties as well as adaptation of unknown parameters in control law, an adaptive sliding mode control through adaptation of unknown parameters is presented to yield the corrective yaw moment such that the yaw rate tracks the desired value and the vehicle sideslip angle maintains limited so as to improve vehicle handling stability. The lower-level controller allocates the achieved control efforts (i.e. total longitudinal force and corrective yaw moment) to driving or regenerative braking torques of four in-wheel motors so as to generate the desired tyre longitudinal forces. The additional yaw moment applied by upper-lever controller may saturate the tyre forces. To this end, a novel longitudinal slip ratio controller which is designed based on fuzzy logic is included in the lower-level controller. A tyre dynamic weight transfer-based torque distribution algorithm is employed to distribute the motor driving torque or regenerative braking torque of each in-wheel motor for vehicle stability enhancement. A seven degree-of-freedom non-linear vehicle model with Magic Formula tyre model as well as the proposed control algorithm are simulated in Matlab/Simulink software. Three steering inputs including lane change, double lane change and step-steer manoeuvres in different roads are investigated in simulation environment. The simulation results show that the proposed control algorithm is capable of improving vehicle handling stability and maintaining vehicle yaw stability.

State Feedback Control Based on Regional Pole Placement on Handling Stability of Ground Vehicles

A controller based on regional pole placement for the handling stability of an intelligent ground vehicle is proposed in this paper. The 2 degree-of-freedom model for the vehicle was applied to analysis the uncertainty generated by the tires and model of the vehicle. Another parameter that must be considered is the change in the vehicle's speed. A polytope with finite vertices was applied for the uncertainty generated by the vehicle's speed in the model. The linear matrix inequality (LMI) method was used to solve the gain of the controller's matrix. Simulations were also used to verify the performance of the proposed controller. The simulation results prove that the controller can improve the vehicle's handling stability against the uncertainty generated by the parameters.