Chassis Control Research Articles

Intelligent Based Vibration Control towards the Improvement of Vehicle Ride Comfort

The mechanism of vehicle suspension system is splitting the car body from the tire of the car. The suspension system is an important element in vehicle design because it effects the ride comfort and passenger’s safety. These two criteria are conflicting to each other. Therefore, this paper proposes an intelligent chassis control of quarter car active suspension system to enhance the vehicle ride comfort and road holding performance. The fuzzy logic control is designed to maximize the driving comfort by keeping the wheel always in contact with road surfaces. Several scenario has been created for analysis purposes. The performance of the fuzzy logic is compared with the PID control and LQR control method respectively. The novelty of this paper is, the ride comfort is measured up to higher derivative of motion. No significant literature was found on the higher derivative of motion such as jerking to improve the ride comfort. Based on the simulation results, Fuzzy logic outperforms the other two controllers on car body displacement, car body acceleration, wheel deflection and jerking with with higher percentage of improvement compare to PID control and passive suspension system.

On the control strategies for vehicle stability enhancement

Currently, vehicle stability enhancement is the main objective of automotive suppliers to enhance the vehicle overall performance and handling. In this paper, different active vehicle chassis control systems and all the available techniques of integration will be discussed. At the beginning a description of the main systems used will be presented then the necessity for a combination of these active chassis control systems is studied followed by a comprehensive review about the state-of-the-art approaches. The purpose of this study is to support automotive manufacturers and suppliers to reach an integrated vehicle chassis control architecture for flexible designs.

On the control strategies for vehicle stability enhancement

Currently, vehicle stability enhancement is the main objective of automotive suppliers to enhance the vehicle overall performance and handling. In this paper, different active vehicle chassis control systems and all the available techniques of integration will be discussed. At the beginning a description of the main systems used will be presented then the necessity for a combination of these active chassis control systems is studied followed by a comprehensive review about the state-of-the-art approaches. The purpose of this study is to support automotive manufacturers and suppliers to reach an integrated vehicle chassis control architecture for flexible designs.

Coordinated Chassis Control of 4WD Vehicles Utilizing Differential Braking, Traction Distribution and Active Front Steering

This paper proposes a coordinated chassis control (CCC) utilizing four-wheel differential braking, electronically controlled real-time four-wheel drive (4WD) and active front steering (AFS), aiming to improve the driving performance and handling stability during cornering. First, the performance of the single system is tested; then the hierarchical-structure control algorithm is designed: a supervisory controller to monitor vehicle states and determine the desired yaw rate, upper-level controller to decide the desired longitudinal forces and the desired yaw moment based on the driver intention and the consideration of vehicle stability, and the control allocation layer to distribute the actual control inputs to the actuators applying an optimal control allocation algorithm. Simulations of moderate driving/aggressive deceleration scenarios and a comprehensive test on a handling road are conducted to validate the effectiveness of the proposed control algorithm. The results of the simulations suggest that the proposed algorithm can effectively improve the driving speed in limit cornering without losing lateral stability, and reduce the tire dissipation energy compared with other control algorithms such as the electronic stability control system, the four wheel independent brake system and an integrated chassis control system proposed in a previous research.

Rear-Wheel Steering Control for Enhanced Steady-State and Transient Vehicle Handling Characteristics

This paper presents a rear-wheel steering (RWS) control algorithm to enhance the vehicle handling performance without prior knowledge of tire characteristics. A RWS system is a chassis control module that can effectively improve vehicle maneuverability and stability. Since the tire-road friction coefficient is difficult to obtain in real world application, the proposed RWS control algorithm is designed so that it can be implemented without any tire-road information. The proposed RWS control algorithm consists of steady-state and transient control inputs. The steady-state control input is proportional to the driver's steering input for achieving the desired yaw rate gain. The desired yaw rate gain is obtained through an offline optimization that is aimed to minimize the vehicle lateral velocity. The transient control input consists of feedforward and feedback control inputs. The feedforward input is designed to improve transient responses of the yaw rate. Computer simulation studies have shown that a trade-off relationship between overshoot and response time exists when the RWS control input is a sum of the steady-state and feedforward inputs. To compromise this conflict, a feedback input has been designed. The overshoot can be significantly reduced while the response time is slightly changed via the feedback input. The proposed algorithm has been investigated via computer simulations. The simulation has been conducted for step steer and sine with dwell scenarios under various road friction conditions. The performance of a RWS vehicle was evaluated using objective indices. Simulation results show that the proposed algorithm enhances vehicle handling performance.

Integrated Active Control of Electric Vehicles

This work describes how it is possible to integrate active chassis control actions in an electric vehicle. A vehicle with Active Front Steering (AFS) is considered, which imposes an incremental steer angle to the front wheels. Using Permanent Magnet Synchronous Motors (PMSMs) as powertrain, fitting on the left/right wheel axle shafts, it is possible to impose not only a desired longitudinal traction, but also an appropriate active yaw torque, so mimicking a classic Rear Torque Vectoring (RTV). The AFS, along with the RTV, allow imposing a desired behavior for the active chassis control of the vehicle, so improving its safety.

A centralized multilayer LPV/H∞ control architecture for vehicle’s global chassis control, and comparison with a decentralized architecture

This paper deals with the development of Global Chassis Controller where the Active Front steering, Direct Yaw Control and Active Suspensions, are coordinated together in the aim to improve the overall vehicle performance i.e maneuverability, lateral stability and rollover avoidance. The main contribution of this work is the integration of the Active suspension system (AS) in a centralized multilayer control architecture to control the roll angle. A polytopic approach is used to find the LPV/H∞ controller where an offline Linear Matrix Inequality (LMI) optimal solver is used to realize the optimality of this controller. The different layers of this architecture are detailed. The proposed LPV/H∞ controller is validated by simulation using Matlab/Simulink, and a comparison is done with a decentralized architecture that has been developed in the laboratory, to show the difference in behavior and performance of both strategies of control and the effectiveness of centralized one on the rollover avoidance.

Model-based chassis control system for an over-actuated planetary exploration rover

Abstract In planetary exploration, wheeled mobile robots (rovers) are popular for extending action range compared to a lander. Despite their success, they continue to struggle with soft grounds which shows in high sinkage and can lead to an immobilization in the worst case. Rovers usually are over-actuated due to individual wheel drives and steering, which is rarely made use of in current missions. Some work optimizing the resulting degrees of freedom exists but often does not use all available model knowledge. In this work, the rover is consequently modeled with the subsystems rigid body dynamics, kinematics and wheel/ground dynamics. Feedback linearization is used for the rigid body and the underlying wheel/ground controllers on individual wheel level. The control allocation of the forces is done via the pseudo-inverse and a base of the null-space to extract the available degrees of freedom. A verification of the approach is shown in a co-simulation with a high-fidelity model of the ExoMars rover.

Optimal robust control of vehicle lateral stability using damped least-square backpropagation training of neural networks

Chassis control systems play a significant role in achieving the desired vehicle performance and stability during various severe maneuvers. A probabilistic estimation approach by hybridization of optimal robust control and a damped least-square backpropagation based neural networks (NN) is proposed to design a control system for dealing with unknown nonlinear dynamics of a passenger car. To this end, a four-wheel active steering (4WAS) model is employed and a multilayer perceptron (ML) feed-forward backpropagation neural network (FFBPNN) model is developed as an approximator. The optimal robust control is employed to regulate the yaw rate and side-slip angle of the vehicle to follow the desired vehicle response. The developed FFBPNN model is trained to distinguish the nonlinear dynamics of the vehicle and the corresponding optimal feedback gain during a wide range of operating conditions via the state variables. The robustness of the controller is evaluated using Lyapunov stability method. The performance of the proposed controller is analyzed considering the open-loop and closed-loop responses of the nonlinear vehicle model and a sliding mode controller to track the desired yaw rate and side-slip angle responses. The results obtained during severe maneuvers suggest that the proposed control method can substantially enhance the handling and stability performances of the vehicle.

Game-Based Hierarchical Cooperative Control for Electric Vehicle Lateral Stability via Active Four-Wheel Steering and Direct Yaw-Moment Control

A Stackelberg game-based cooperative control strategy is proposed for enhancing the lateral stability of a four-wheel independently driving electric vehicle (FWID-EV). An upper‒lower double-layer hierarchical control structure is adopted for the design of a stability control strategy. The leader‒follower-based Stackelberg game theory (SGT) is introduced to model the interaction between two unequal active chassis control subsystems in the upper layer. In this model, the direct yaw-moment control (DYC) and the active four-wheel steering (AFWS) are treated as the leader and the follower, respectively, based on their natural characteristics. Then, in order to guarantee the efficiency and convergence of the proposed control strategy, a sequential quadratic programming (SQP) algorithm is employed to solve the task allocation problem among the distributed actuators in the lower layer. Also, a double-mode adaptive weight (DMAW)- adjusting mechanism is designed, considering the negative effect of DYC. The results of cosimulation with CarSim and Matlab/Simulink demonstrate that the proposed control strategy can effectively improve the lateral stability by properly coordinating the actions of AFWS and DYC.

Chassis integrated control for 4WIS distributed drive EVs with model predictive control based on the UKF observer

Four-wheel independent steering (4WIS) system and direct yaw moment control (DYC) have an important influence on vehicle lateral stability. However, DYC has a great effect on the longitudinal velocity, and the capability of 4WIS is limited to stability. To decrease the influence on the longitudinal velocity and improve the stability of electrical vehicles, a chassis controller integrated with a 4WIS system and a DYC system with model predictive control (MPC) is designed. The framework consists of an unscented Kalman filter (UKF) observer and an MPC that contains three blocks: supervisor blocks, upper blocks and lower blocks. First, the sideslip angle, longitudinal velocity and lateral tire forces are estimated by the UKF observer; second, a bicycle model is utilized in the supervisor to calculate the desired values; third, the upper blocks are designed with the MPC to optimize the target steering angles and longitudinal tire forces under the constraints of subsystems; to facilitate the design of the MPC, a nonlinear tire is simplified based on the Taylor expansion method; finally, the target steering angles and longitudinal tire forces are achieved by the lower blocks. The integrated controller is simulated on the co-simulation platform of MATLAB-Carsim. The results show that the proposed integrated controller has less impact on longitudinal velocity and could effectively improve vehicle stability.

Integrated Vehicle Dynamics System through Coordinating Active Aerodynamics Control, Active Rear Steering, Torque Vectoring and Hydraulically Interconnected Suspension

This paper investigates integrated vehicle dynamics control through coordinating active aerodynamics control, active rear steering, torque vectoring and hydraulically interconnected suspension for improving the overall vehicle performance including handling, stability, and comfort. After developing each chassis control system, it is tested by various manoeuvres in order to assess each subsystem. Then, a rule-based coordinate system is proposed for integrated control of the four chassis control systems. Simulation investigation is performed to display the effectiveness of the proposed integrated vehicle dynamics system. Results demonstrate that the proposed control scheme is able to enhance the multiple performance indices of the vehicle including both the ride comfort, and the lateral stability, compared to the non-integrated control system.

횡방향 안정성 향상을 위한 샤시통합제어 개발

횡방향 안정성 향상을 위한 샤시통합제어 개발

Design of a central feedforward control of torque vectoring and rear-wheel steering to beneficially use tyre information

ABSTRACT This paper presents the design of a central feedforward control for the two chassis control systems rear-wheel steering (RWS) and torque vectoring (TV) which have related areas of intervention in lateral dynamics. A control strategy is presented in order to follow desired target values consisting of yaw acceleration and sideslip angle velocity. Central attention is given to the use of additional tyre information with the aim of enhancing vehicle handling and stability. With the knowledge of the mounted tyre type, an adaption law for the desired target values is derived. Although the focus is based on the usage of new tyre information, this modelling approach basically has the potential to reduce the need for coordination among the two systems RWS and TV, exploiting the synergies between both of them. Starting from an extended single-track model an exact Input–output linearisation method is used to design the feedforward control. This is followed by a proof of stability for the external and the internal dynamics of the controller. For the subsequent investigation, in a preliminary step, real-world in vehicle tests are carried out under varying tyre types with a wide spreading of characteristics. This serves as a basis to identify the most important tyre parameters for the controller and to derive the target goals. Finally, the controller is implemented in a 14-DOF non-linear entire vehicle model in Matlab/Simulink, that serves for simulations with a virtual vehicle plant. The performance of the presented feedforward control is assessed by specified objective criteria for steady-state and transient open-loop manoeuvres in lateral dynamics. These criteria are used to investigate the effectiveness of the control design with the aim to achieve the defined target motion. In addition to that, the manoeuvre results also serve to evaluate the control effort, involved in the coordinated cooperation of both systems.

Optimization of control allocation with ESC, AFS, ARS and TVD in integrated chassis control

This paper presents an optimization of control allocation in integrated chassis control with active front steering, active rear steering, electronic stability control and torque-vectoring device under the saturation of lateral tire forces on front wheels. After a control yaw moment is calculated in the upper-level controller, a weighted pseudo-inverse based control allocation is used for yaw moment generation in the lower-level controller. Variable coefficients of the weighted pseudo-inverse based control allocation are used to represent various actuator combinations and are optimized for each actuator combination to enhance control performances using simulation on vehicle simulation package, CarSim. Due to severe cornering on low friction road, the front lateral tire forces can be easily saturated. Under the condition, the active front steering has little effect on control performance and, consequently, the desired control yaw moment cannot be generated. So, the lateral force generated by AFS should be restricted to its maximum, and a constrained weighted pseudoinverse based control allocation with electronic stability control, active rear steering and torque-vectoring device is applied to compensate the loss of the control yaw moment. Variable coefficients of the constrained weighted pseudo-inverse based control allocation with electronic stability control, active rear steering and torque-vectoring device are also optimized using simulated-based tuning. To validate the proposed method, simulation was done on CarSim. From simulation, it was verified which actuator combination is effective for integrated chassis control if the lateral forces on front wheels are saturated.

Integrated chassis control with AFS, ARS and ESC under lateral force constraint on AFS

This paper presents an integrated chassis control with active front steering (AFS), active rear steering (ARS) and electronic stability control (ESC) under lateral force constraint on front wheels. The control yaw moment is calculated using sliding mode control. A weighted pseudo-inverse-based control allocation (WPCA) is used for yaw moment distribution. On low-friction road, AFS has little effect on control performance since the lateral tire forces of front wheels are easily saturated. To overcome the problem, the lateral force generated by AFS is limited to its maximum, and the braking force of ESC and the angle of ARS, obtained from WPCA, are applied. To check the effectiveness of the proposed method, simulation was performed on the vehicle simulation package, CarSim. From simulation, it was verified that the proposed method can enhance the maneuverability and lateral stability, if the lateral forces on front wheels are saturated.

Robust Control in Diagonal Move Steer Mode and Experiment on an X-by-Wire UGV

This paper proposes a novel X-by-wire unmanned ground vehicle (UGV)-unmanned ground carrier (UGC). To show functions of the UGV, the mechanisms and design processes of the key subsystems are described, especially the in-wheel motor-driven and independent steer subsystems. As an all-wheel-independently steered (AWIS) UGV, the UGC is able to achieve the diagonal move steer mode (DMSM) to improve the maneuverability significantly. To improve the path tracking performance in DMSM, a robust H2/H∞ chassis yaw controller is proposed, which uses the additional yaw moment provided by in-wheel motors to track the desired sideslip angle and avoid the yaw motion. The energy to peak and energy to energy performance of the sideslip angle and the yaw velocity are considered and handled by linear matrix inequalities (LMIs) approach during the H2/H∞ controller design. The parametric uncertainties and disturbances of the vehicle mass, the yaw inertia, and tire cornering stiffness are considered to improve the robustness. Finally, the step steer and lane change tests are conducted with the UGV testbed to validate the efficiency and robustness of the proposed chassis controller.

Challenges of Integrated Vehicle Chassis Control: Some Findings of the European Project EVE

The European Union Horizon 2020 Framework Program, Marie Skdowska-Curie actions, under grant agreement no.645736.

전륜 횡력 포화 시 요모멘트 보상을 위한 통합 섀시 제어

In this paper, we present the integrated chassis control strategy with electronic stability control (ESC), active rear steering (ARS) and torque vectoring device (TVD) under the saturation of the lateral tire force on front wheels, caused by the excessive application of active front steering (AFS). The control yaw moment was calculated using sliding mode control. Contrary to the previously proposed method that uses the optimization-based method, the simple distribution method was adopted under the assumption that a single actuator of the chassis control system was used for yaw moment distribution. The lateral tire forces of front wheels were easily saturated by the excessive sole application of AFS. To cope with the situation, the corrective steering angle of AFS has been limited, and it compensated the loss of the control yaw moment with ESC, ARS and TVD in this paper. For verification of the effectiveness of the proposed control method, simulation has been performed via the vehicle simulation tool package, CarSim. From simulation, it has been verified that the proposed method can enhance maneuver performance and lateral stability if the lateral forces on front wheels are saturated.

Comprehensive chassis control strategy of FWIC‐EV based on sliding mode control

Four-wheel independent control electric vehicle has possessed tremendous potentials because the enhancement of driving performance and energy savings can be simultaneously carried out by independent and precise driving/braking/steering control. The study has proposed a comprehensive control strategy aiming at all normal conditions, which employs hierarchical architecture to reach the above-mentioned control. In the high-level controller, sliding mode control scheme is developed to figure out total force and yaw moment. In the low-level controller, energy-efficiency optimisation allocation is presented to reduce motor power losses and obtain energy recovery based on motor efficiency map, and then steering angle allocation is conducted to decrease the lateral force so as to reduce power losses caused by the tyre sideslip. Considering insufficient motor braking torque during large deceleration or even larger, the blended brake control strategy with the motor brake and electric hydraulic brake and further anti-skid brake system control via adopting fuzzy logic method are carried out. The torque and pressure are gained to deliver the corresponding actuators model established according to their physical characteristics. Through CarSim-MATLAB/Simulink-AMEsim co-simulation, results suggest that the developed strategy can boost the vehicle manoeuvrability and reduce energy consumption generated by motors and tyre sideslip under all the conventional occasions.