基于结构化道路与NMPC的无人车路径跟踪控制

Path tracking control of unmanned vehicle based on structured road and NMPC

针对无人驾驶汽车路径规划与跟踪控制问题,设计了一种分层控制器。上层采用汽车运动学模型,并在满足系统动态方程、边值、路径约束下,设计了基于结构化道路的的代价函数完成路径规划。下层基于双自由度动力学模型设计惩罚函数以转向与加速指引车辆实现路径跟踪。利用SOA算法在线整定控制器参数,并通过Carsim/Simulink进行预定参考速度下仿真,仿真试验得出横摆角速度最值在7.5(°)/s左右的可控范围内波动,纵向加速度最值在0.4 m/s^(2)左右、前轮转角为7°在约束范围内,在考虑舒适性前提下的路径跟踪平均偏移量为0.041 m,纵向控制下车速跟踪平均偏差为0.038 m/s。试验结果表明:所设计的控制器具有良好的跟踪控制效果与稳定性。

A hierarchical controller is designed for the path planning and tracking control of unmanned vehicles.The upper layer adopts the automobile kinematics model,and designs the cost function based on the structured road to complete the path planning under the condition of satisfying the system dynamic equation,boundary value and path constraints.The lower layer designs a penalty function based on the two-degree-of-freedom dynamic model to steer and accelerate the vehicle to realize path tracking.The SOA algorithm is used to tune the controller parameters online,and the simulation is carried out at the preset reference speed by Carsim/Simulink.The simulation results show that the maximum yaw rate fluctuates within the controllable range of about 7.5(°)/s,the maximum longitudinal acceleration is about 0.4 m/s^(2),the front wheel rotation angle is 7°within the constraint range,the average deviation of path tracking under comfort is 0.041 m,and the average deviation of vehicle speed tracking under longitudinal control is 0.038 m/s.The experimental results show that the designed controller has good tracking control effect and stability.