自动泊车转向路径跟踪定位优化控制研究

Automatic Parking Path Tracking Control Research

结合自动泊车系统(Automatic Parking System),针对自动泊车中车速控制不当导致车辆偏离目标路径以及泊车转向跟踪误差大的问题。提出了基于非时间参考的无模型自适应控制的路径跟踪转向控制策略,摆脱车辆加减速带来的时域约束,达到更高效率的跟踪泊车路径。针对几何路径的跟踪建立车辆运动学模型。模型以随时间递增的非时间变量作为控制参考量,根据X轴的坐标变化提供跟踪目标前轮转角值。另外,采用无模型自适应控制(MFAC)精确控制前轮转向进行跟踪,输入值为前轮转角,得到车身姿态角值,从而实现目标车身角的跟踪,无需具体的对象模型信息,提高路径跟踪的精准度。在不同车速工况下,与PID控制进行对比仿真,结果表明非时间参考跟踪生成的目标转角准确,MFAC方法比PID控制在转向控制上精度更高,响应更快。验证了控制策略的有效性。

Based on the Automatic Parking System and in view of the problems of leaving from the target path be cause unbefitting velocity control and the parking direction tracking error is higher,a non-time-based model-free adaptive control path tracking steering control strategy was proposed to eliminate the time domain constraints brought by the acceleration and deceleration of vehicles,so as to follow the parking path more efficiently.The vehicle kine matics model was established for the tracking of the geometric path.We defined the non-time variable that increases with time as the control reference variable,and the tracking target forward wheel angle was provided according to the coordinate change of the X axis.In addition,the Model-free Adaptive Control(MFAC)strategy was used to pre cisely control front wheel steering for tracking.The input value was the front wheel angle,and the orientation angle of the car was obtained,so as to achieve the target body angle tracking without specific object model information,and improved the accuracy of path tracking.Compared with PID control under different vehicle speed conditions,the re sults show that target forward rotation angle generated by a non-time reference is more accurate,the MFAC method has higher precision and faster response than PID control in the steering control.The validity of the control strategy was verified.