Terminal Traction Control of Teleoperation Manipulator With Random Jitter Disturbance Based on Active Disturbance Rejection Sliding Mode Control

The present study proposes an active disturbance rejection sliding mode traction control system to deal with the dramatic change of joint angular acceleration and jitter attributed to non-uniform traction during terminal traction of the manipulator based on the use of human-computer interaction (HCI) device, as well as achieve the high-precision and high-speed terminal traction control. First, the traction trajectory generated by the HCI device is mapped into the motion space of the manipulator, and a low-pass filter is employed to filter out the high-frequency noises attributed to non-uniform traction. Second, the corresponding joint solution of the traction trajectory is solved by using the inverse kinematics algorithm. Then the nonlinear and strongly coupled manipulator is linearly decoupled. Lastly, the effect of non-uniform traction on the manipulator’s joints is considered as interference, and an active disturbance rejection sliding mode controller is introduced for each joint. To reduce the chattering, the output torque of the controller is processed with a low-pass filter. The stability of the controller is proved with the Lyapunov method. To verify the traction effect of the traction control system and its anti-interference ability for non-uniform traction, the trajectory tracking experiment with random jitter and the real terminal traction control experiment is performed on the UR5 manipulator in the virtual robot experiment platform. As revealed from the experimentally achieved results, the proposed controller can significantly limit the effect of non-uniform traction on each joint of the manipulator and achieve the fast, stable, and high-precision terminal traction control of the manipulator by the HCI device.

本研究提出一种自抗扰滑模牵引控制系统，用于处理在基于人机交互（HCI）设备的机械臂末端牵引过程中，由于不均匀牵引导致的关节角加速度的急剧变化和抖动，并实现高精度和高速的末端牵引控制。首先，将人机交互设备产生的牵引轨迹映射到机械臂的运动空间，并采用低通滤波器滤除由于不均匀牵引产生的高频噪声。其次，利用逆运动学算法求解牵引轨迹的相应关节解。然后对非线性且强耦合的机械臂进行线性解耦。最后，将不均匀牵引对机械臂关节的影响视为干扰，并为每个关节引入一个自抗扰滑模控制器。为了减少抖振，用低通滤波器对控制器的输出扭矩进行处理。利用李雅普诺夫方法证明了控制器的稳定性。为了验证牵引控制系统的牵引效果及其对不均匀牵引的抗干扰能力，在虚拟机器人实验平台上的UR5机械臂上进行了带有随机抖动的轨迹跟踪实验和实际末端牵引控制实验。从实验结果可以看出，所提出的控制器能够显著限制不均匀牵引对机械臂每个关节的影响，并通过人机交互设备实现机械臂快速、稳定和高精度的末端牵引控制。