基于轨迹跟踪的农用履带机器人自适应滑模控制

Adaptive sliding mode control for agricultural tracked robot based on trajectory tracking

为了提高农用履带机器人轨迹跟踪控制的性能,在履带机器人运动学模型的基础上,设计了自适应滑模控制,构建了一种变倾斜参数的自适应积分滑模切换函数,基于这个函数提出了由等效控制和切换控制组成的自适应滑模跟踪控制,将机器人的位姿误差,以及在线辨识的时变不确定参数反馈至控制器中,计算出左右轮驱动电机的期望角速度,同时利用李亚普诺夫方法证明了所设计滑模跟踪控制的稳定性。田间试验结果表明,当机器人以1~4 m/s速度运行时,在运动方向距离误差、侧向距离误差和航向角的误差分别为-0.04~0.04 m,-0.09~0.07m和-0.03~0.05 rad。因此,机器人自适应滑模控制具有良好的控制精度,能够满足田间实际作业的要求。

To improve the performance of trajectory tracking control for agricultural tracked robot（ ATR）,on the basis of the dynamic characteristics of kinematics model,a sliding mode control module and an integral sliding mode switching function（ ISMSF） were proposed. Furthermore,an adaptive sliding mode trajectory tracking control（ ASMTTC） was developed based on ISMSF,which was composed of equivalent control and nonlinear switch control. The ASMTTC could feed back the position and orientation error and the time-varying parameters to the controller,so the expected angular velocities of the left and right driving wheels could be calculated. Finally,the stability of ASMTTC was proved by Lyapunov method.The results showed that： when the ATR ran at speed of 1-4 m/s,the tracking error for ATR ranged from-0. 04 m to 0. 04 m,from-0.09 m to 0. 07 m in the direction of motion and lateral distance,respectively,and heading error ranged from-0.03 rad to 0. 05 rad. In conclusion,the ASMTTC of robot had good control accuracy and can meet the requirements of field operation.