An active front steering （AFS） intervention control during braking for vehicle stability is presented. Based on the investigation of AFS mechanism, a simplified model of steering system is established and integrated...An active front steering （AFS） intervention control during braking for vehicle stability is presented. Based on the investigation of AFS mechanism, a simplified model of steering system is established and integrated with vehicle model. Then the AFS control on vehicle handling dynamics during braking is designed. Due to the difficulties associated with the sideslip angle measurement of vehicle, a state observer is designed to provide real time estimation. Thereafter, the controller with the feedback of both sideslip and yaw angle is implemented. To evaluate the system control, the proposed AFS controlled vehicle has been tested in the Hardware-in-the-loop-simulation （HILS） system and compared with that of conventional vehicle. Results show that AFS can improve vehicle lateral stability effectively without reducing the braking performance.展开更多
The steering characteristic of a four-wheel-steering vehicle is numerically simulated for in-depth research of the handling stability of four-wheel steering. The research results show that the deteriorating tendency o...The steering characteristic of a four-wheel-steering vehicle is numerically simulated for in-depth research of the handling stability of four-wheel steering. The research results show that the deteriorating tendency of the steering stability due to the increase of the vehicle speed is improved obviously in the case of four-wheel steering. The approach of variable steering ratio is discussed. The use of the variable steering ratio can not only raise the steering stability of vechicles at high vehicle speed, but also reduce the dicomfort and steering burden of drivers; and hence is helpful for the subjective evaluation of four-wheel steering vehicles.展开更多
Four wheel steering(4 WS) technology can effectively improve the vehicle handling stability and driving safety. In order to fully consider the influence of the rear wheel steering, the vehicle dynamics model of 4 WS v...Four wheel steering(4 WS) technology can effectively improve the vehicle handling stability and driving safety. In order to fully consider the influence of the rear wheel steering, the vehicle dynamics model of 4 WS vehicle, including the rear wheel steering by wire and two degrees of freedom vehicle model of 4 WS vehicle, is established in this paper. The desired yaw rate is obtained according to the variable transmission ratio strategy. The yaw rate tracking strategy is applied to 4 WS vehicle and rear wheel steering resistance moment is taken into account. Based on the robust control theory, H_2/H_∞ mixed robust controller design is carried to research the stability control of 4 WS vehicle. Finally, the closed-loop simulation added driver model based on preview theory is carried out. The simulation results indicate that the designed H_2/H_∞ mixed robust controller can achieve the stability control.展开更多
文摘An active front steering （AFS） intervention control during braking for vehicle stability is presented. Based on the investigation of AFS mechanism, a simplified model of steering system is established and integrated with vehicle model. Then the AFS control on vehicle handling dynamics during braking is designed. Due to the difficulties associated with the sideslip angle measurement of vehicle, a state observer is designed to provide real time estimation. Thereafter, the controller with the feedback of both sideslip and yaw angle is implemented. To evaluate the system control, the proposed AFS controlled vehicle has been tested in the Hardware-in-the-loop-simulation （HILS） system and compared with that of conventional vehicle. Results show that AFS can improve vehicle lateral stability effectively without reducing the braking performance.
文摘The steering characteristic of a four-wheel-steering vehicle is numerically simulated for in-depth research of the handling stability of four-wheel steering. The research results show that the deteriorating tendency of the steering stability due to the increase of the vehicle speed is improved obviously in the case of four-wheel steering. The approach of variable steering ratio is discussed. The use of the variable steering ratio can not only raise the steering stability of vechicles at high vehicle speed, but also reduce the dicomfort and steering burden of drivers; and hence is helpful for the subjective evaluation of four-wheel steering vehicles.
基金supported by the National Natural Science Foundation of China(Grant No.51375007)the Fundamental Research Funds for the Central Universities(Grant No.NE2016002)Open Foundation of the State Key Laboratory of Fluid Power and Mechatronic Systems(Grant No.GZKF-201605)
文摘Four wheel steering(4 WS) technology can effectively improve the vehicle handling stability and driving safety. In order to fully consider the influence of the rear wheel steering, the vehicle dynamics model of 4 WS vehicle, including the rear wheel steering by wire and two degrees of freedom vehicle model of 4 WS vehicle, is established in this paper. The desired yaw rate is obtained according to the variable transmission ratio strategy. The yaw rate tracking strategy is applied to 4 WS vehicle and rear wheel steering resistance moment is taken into account. Based on the robust control theory, H_2/H_∞ mixed robust controller design is carried to research the stability control of 4 WS vehicle. Finally, the closed-loop simulation added driver model based on preview theory is carried out. The simulation results indicate that the designed H_2/H_∞ mixed robust controller can achieve the stability control.
