三手指空间手爪基于抓握力的模糊自适应控制

摘要

When space robot is capturing an object, the disturbance force produced by interactive collisions may induce the robot arm dithering and distortion; moreover, it may also pop-up the target object away from the capture zone, which would lead to the failure of capturing operation. In allusion to this problem, the fuzzy-based grasp-force-adaptive control strategy was proposed to weaken the disturbance force produced by interactive collisions and to minish the dithering to the robot arm. The design of three-fingered space robot end-effector of Harbin Institute of Technology (HIT) was introduced firstly; and the interactive collisions and the grasping progress were analyzed. The compliance control strategy was proposed, and a robust controller of fuzzy-bassed grasp force adaptive impedance control was designed. The control scheme modified control parameters real-time by fuzzy controller so that the stability and the dynamic behavior were improved; sliding mode controller in the control loop enhanced the robustness of the system. Using satellite on orbit self-servicing manipulator designed by HIT, the strategy proposed and the controller designed were validated by some grasp experiments on micro-gravity platform. Experimental results show that the proposed strategy and the controller designed can eliminate the disturbance force effectively.%针对空间手爪在抓握目标物体的过程中,因接触碰撞而产生的扰动力可能会造成机械臂抖动和初始位姿改变,甚至将目标物体弹出捕获区,造成捕获失败的问题,提出了基于抓握力的模糊自适应控制策略,以削弱在抓握过程中因接触碰撞产生的扰动力,减小对机械臂造成的扰动.首先介绍了哈尔滨工业大学(HIT)自行研制的三手指空间手爪,对其抓握过程和接触碰撞进行了分析,提出一种柔顺控制策略,设计了基于抓握力的模糊自适应控制器.通过模糊控制器实时地调整控制参数,不仅可使系统稳定,而且具有良好的动态品质;控制器中的滑模控制还可以增强系统的鲁棒性.采用HIT在轨自维护机械臂在空间微重力运动平台上进行了抓握实验,实验结果表明设计的控制器和提出的抓握策略能够有效削弱抓握过程中的扰动力.