Shared Control of Highly Automated Vehicles Using Steer-By-Wire Systems

A shared control of highly automated Steer-by-Wire system is proposed for cooperative driving between the driver and vehicle in the face of driver's abnormal driving. A fault detection scheme is designed to detect the abnormal driving behaviour and transfer the control of the car to the automatic system designed based on a fault tolerant model predictive control(MPC) controller driving the vehicle along an optimal safe path.The proposed concept and control algorithm are tested in a number of scenarios representing intersection, lane change and different types of driver's abnormal behaviour. The simulation results show the feasibility and effectiveness of the proposed method.

Kalman Filter-Based Fusion Estimation Method of Steering Feedback Torque for Steer-by-Wire Systems

Universal challenge lies in torque feedback accuracy for steer-by-wire systems,especially on uneven and low-friction road.Therefore,this paper proposes a fusion method based on Kalman filter that combines a dynamics-reconstruction method and disturbance observer-based method.The dynamics-reconstruction method is designed according to the vehicle dynamics and used as the prediction model of the Kalman filter.While the disturbance observer-based method is performed as an observer model of the Kalman filter.The performance of all three methods is comprehensively evaluated in a hardware-in-the-loop system.Experimental results show that the proposed fusion method outperforms dynamics reconstruction method and disturbance observer-based method.Specifically,compared with the dynamics-reconstruction method,the root mean square error is reduced by 36.58%at the maximum on the flat road.Compared with the disturbance observer-based method,the root mean square error is reduced by 39.11%at the maximum on different-friction and uneven road.

Active fault-tolerant control of rotation angle sensor in steer-by-wire system based on multi-objective constraint fault estimator

Purpose–Steer-by-wire(SBW)system mainly relies on sensors,controllers and motors to replace the traditionally mechanical transmission mechanism to realize steering functions.However,the sensors in the SBW system are particularly vulnerable to external influences,which can cause systemic faults,leading to poor steering performance and even system instability.Therefore,this paper aims to adopt a fault-tolerant control method to solve the safety problem of the SBW system caused by sensors failure.Design/methodology/approach–This paper proposes an active fault-tolerant control framework to deal with sensors failure in the SBW system by hierarchically introducing fault observer,fault estimator,fault reconstructor.Firstly,the fault observer is used to obtain the observation output of the SBW system and then obtain the residual between the observation output and the SBW system output.And then judge whether the SBW system fails according to the residual.Secondly,dependent on the residual obtained by the fault observer,a fault estimator is designed using bounded real lemma and regional pole configuration to estimate the amplitude and time-varying characteristics of the faulty sensor.Eventually,a fault reconstructor is designed based on the estimation value of sensors fault obtained by the fault estimator and SBW system output to tolerate the faulty sensor.Findings–The numerical analysis shows that the fault observer can be rapidly activated to detect the fault while the sensors fault occurs.Moreover,the estimation accuracy of the fault estimator can reach to 98%,and the fault reconstructor can make the faulty SBW system to retain the steering characteristics,comparing to those of the fault-free SBW system.In addition,it was verified for the feasibility and effectiveness of the proposed control framework.Research limitations/implications–As the SBW fault diagnosis and fault-tolerant control in this paper only carry out numerical simulation research on sensors faults in matrix and laboratory/Simulink,the subsequent hardware in the loop test is needed for further verification.Originality/value–Aiming at the SBW system with parameter perturbation and sensors failure,this paper proposes an active fault-tolerant control framework,which integrates fault observer,fault estimator and fault reconstructor so that the steering performance of SBW system with sensors faults is basically consistent with that of the fault-free SBW system.