考虑输入饱和的机械臂轨迹跟踪滑模控制

Sliding mode control for trajectory tracking of robotic manipulator based on input saturation

针对复合干扰和输入饱和特性影响机械臂轨迹跟踪精度的问题,给出了一种基于输入饱和补偿的自适应积分滑模控制策略。首先,基于自适应控制方法设计了辅助函数,以消除输入饱和特性的影响;其次,利用所估计的复合干扰上限,结合非奇异积分终端滑模控制方法设计轨迹跟踪控制律,使跟踪误差快速收敛至零的邻域,且削弱了抖振,经过Lyapunov稳定性定理的证明,该算法可以保证轨迹跟踪误差的有限时间收敛性;最后,通过仿真与实验手段,与自适应非奇异快速终端滑模控制方法的对比验证了所提控制方法的有效性。结果表明:机械臂各关节在仿真和实验中分别可以在0.5 s和0.8 s内跟踪上期望轨迹,跟踪误差能降低到1.2×10^(-3)rad和8.7×10^(-3)rad内,有效解决机械臂输入饱和问题和复合干扰对系统轨迹跟踪控制精度的影响。

To address the issues of complex disturbance and input saturation that affect the trajectory tracking accuracy of the robotic manipulator,an adaptive integrated sliding mode control technique based on input saturation compensation was proposed.Firstly,an auxiliary function was designed based on the adaptive control method to get rid of the input saturation trait.Secondly,the trajectory tracking control law was designed by the estimated upper limit of complex disturbance and the non-singular integral terminal sliding mode control method,which made the tracking error converge to the zero neighborhood quickly and weakened chattering.The Lyapunov stability theorem was used to demonstrate that the algorithm could ensure the finite-time convergence of trajectory tracking error.Finally,the effectiveness of the adaptive non-singular fast terminal sliding mode control method was verified by comparing with the existing control methods through simulation and experimentation.The results show that each joint of the manipulator can track the desired trajectory within 0.5 s and 0.8 s in simulation and experiment,respectively,and the tracking error can be reduced to 1.2×10^(-3) rad and 8.7×10^(-3) rad,which can effectively solve the input saturation problem of the manipulator and lessen the influence of complex disturbance on the control accuracy of the system trajectory tracking.