机械臂自适应精确时间滑模控制

考虑机械臂中存在的未建模部分、摩擦力、外加干扰,提出一种自适应精确时间滑模控制方法,实现机械臂各关节角的轨迹跟踪.首先对机械臂进行建模,将未建模部分、摩擦力、外加扰动看作集中扰动;其次,设计一种精确时间收敛滑模面,克服传统终端滑模面收敛时间高估的问题,基于此设计全局精确时间收敛滑模控制方法,使得机械臂系统能够在设定时间实现稳定,并在误差收敛后仍具有较强的鲁棒性;接着,设计低通滤波器削减抖振,通过自适应方法估计扰动上界,避免增益的高估;最后,通过仿真实验验证所提出的控制方法能够严格控制机械臂系统的稳定时间,并降低稳态误差,实现机械臂系统的高精度轨迹跟踪控制.

Adaptive exact-time sliding mode control for manipulator

Considering the problems of unmodeled parts, friction and external interference in the practical application of the manipulator, an adaptive exact-time sliding mode control method is proposed to realize the trajectory tracking of each joint of the manipulator. Firstly, the manipulator is modeled, and the unmodeled part, friction force and external disturbance are regarded as concentrated disturbances. Secondly, an exact-time sliding mode surface is designed to overcome the problem of overestimation of the convergence time of the traditional terminal sliding mode surface. Based on this, a global exact-time convergent sliding mode control method is designed for the manipulator system, which enables the manipulator system to achieve stability at the setting time and keep strong robustness after setting time. The upper bound of the disturbance is estimated by an adaptive method to avoid overestimation of the gain. Then a low-pass filter is designed to reduce chattering. Finally, the control method is simulated. The results show that the proposed control method can strictly control the stability time of the manipulator system, reduce the steady-state error, and achieve high-precision trajectory tracking control of the manipulator system.