四轮转向汽车控制策略及稳定性研究

Control Strategy and Stability of Four-wheel Steering Automobiles

提出了一种四轮转向横向控制和制动力纵向联合控制(4WS-DYC)的控制策略。建立了二自由度车辆动力学模型,计算稳态时车辆的质心侧偏角和横摆角速度;基于最优控制理论建立了四轮转向LQR控制器和分层制动力纵向控制器;最后验证了双移线工况下控制策略的效果。结果表明:4WS-DYC控制策略有效,相比Car-Sim自带模型,低速时质心侧偏角降低了65%,高速时横摆角速度下降了34%。

A control strategy of joint lateral control of four-wheel steering and longitudinal control of the braking force(4WS-DYC)was proposed.A two-degree-of-freedom vehicle dynamics model was estab-lished to calculate the centroid deflection angle and yaw angular velocity of the vehicle at a steady state.Based on the optimal control theory,a linear quadratic regulator(LQR)controller of four-wheel steering and a longitudinal controller of hierarchical braking force were established.Finally,the effect of the control strategy under the condition of double line shift was verified.The experimental results show that the 4WS-DYC control strategy is effective.Compared with the CarSim model,the centroid deflection angle is reduced by 65%at low speed,and the yaw angular velocity is reduced by 34%at high speed.