Haptic control of steer-by-wire systems for tracking of target steering feedback torque

Author(s):  
Jaepoong Lee ◽  
Kyongsu Yi ◽  
Dongpil Lee ◽  
Bongchoon Jang ◽  
Minjun Kim ◽  
...  

This study proposes a haptic control of steer-by-wire systems for tracking a target steering feedback torque to achieve the conventional steering feedback torque. The haptic feedback control with a steer-by-wire steering-wheel system model was used to provide drivers with a conventional steering feedback torque. The steer-by-wire steering-wheel system model was developed, and a haptic control algorithm was designed for a desired steering feedback torque with a three-dimensional target steering torque map. In order to track the target steering torque to let the drivers feel the conventional steering efforts, an adaptive sliding-mode control was used to ensure robustness against parameter uncertainty. The angular velocity and angular acceleration used in the control algorithm were estimated using an infinite impulse response filter. The performance of the proposed controller was evaluated by computer simulation and hardware-in-the-loop simulation tests under various steering conditions. The proposed haptic controller successfully tracked the steering feedback torque for steer-by-wire systems.

Author(s):  
Aria Noori Asiabar ◽  
Reza Kazemi

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.


Author(s):  
Jaepoong Lee ◽  
Kwang Il Kim ◽  
Minjun Kim ◽  
Kyongsu Yi

This paper describes a haptic control of steer-by-wire systems for rendering the conventional steering system under various road conditions using parameter estimation of rack system lateral load model. To design the conventional steering system model, the dynamic model of a rack system has been developed as a mass-spring-damper system with a friction model. An online parameter estimation of the rack system was designed to consider the various road conditions in the haptic rendering. In a steering wheel system, which is a haptic device, a limit cycle, and instable behavior can occur due to the sampling rate and quantization. To prevent the limit cycle and instable behavior, a passivity analysis was conducted and constraint conditions of the rendering coefficient was derived. The haptic control algorithm is designed to render the conventional steering system without limit cycles using passivity conditions. The performance of the proposed controller was evaluated via both computer simulations and vehicle tests under various steering conditions. The results demonstrate that the proposed algorithm ensures haptic rendering performance on dry and wet asphalt conditions.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liang Su ◽  
Zhenpo Wang ◽  
Chao Chen

Purpose The purpose of this study is to propose a torque vectoring control system for improving the handling stability of distributed drive electric buses under complicated driving conditions. Energy crisis and environment pollution are two key pressing issues faced by mankind. Pure electric buses are recognized as the effective method to solve the problems. Distributed drive electric buses (DDEBs) as an emerging mode of pure electric buses are attracting intense research interests around the world. Compared with the central driven electric buses, DDEB is able to control the driving and braking torque of each wheel individually and accurately to significantly enhance the handling stability. Therefore, the torque vectoring control (TVC) system is proposed to allocate the driving torque among four wheels reasonably to improve the handling stability of DDEBs. Design/methodology/approach The proposed TVC system is designed based on hierarchical control. The upper layer is direct yaw moment controller based on feedforward and feedback control. The feedforward control algorithm is designed to calculate the desired steady-state yaw moment based on the steering wheel angle and the longitudinal velocity. The feedback control is anti-windup sliding mode control algorithm, which takes the errors between actual and reference yaw rate as the control variables. The lower layer is torque allocation controller, including economical torque allocation control algorithm and optimal torque allocation control algorithm. Findings The steady static circular test has been carried out to demonstrate the effectiveness and control effort of the proposed TVC system. Compared with the field experiment results of tested bus with TVC system and without TVC system, the slip angle of tested bus with TVC system is much less than without TVC. And the actual yaw rate of tested bus with TVC system is able to track the reference yaw rate completely. The experiment results demonstrate that the TVC system has a remarkable performance in the real practice and improve the handling stability effectively. Originality/value In view of the large load transfer, the strong coupling characteristics of tire , the suspension and the steering system during coach corning, the vehicle reference steering characteristics is defined considering vehicle nonlinear characteristics and the feedforward term of torque vectoring control at different steering angles and speeds is designed. Meanwhile, in order to improve the robustness of controller, an anti-integral saturation sliding mode variable structure control algorithm is proposed as the feedback term of torque vectoring control.


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