三手指空间机器人末端执行器的柔顺抓握策略  

Compliant Grasp Strategy for Three-fingered Space Robot End-effector

作　　者：张庆利[1] 倪风雷[1] 朱映远[1] 党进[1] 刘宏[1,2] 

机构地区：[1]哈尔滨工业大学机器人技术与系统国家重点实验室,黑龙江哈尔滨150080 [2]德国宇航中心机器人与机电一体化研究所,德国慕尼黑82230

出　　处：《机器人》2011年第4期427-433,共7页Robot

基　　金：国家863计划资助项目(2008AA12A213);教育部"111"创新引智计划资助项目(B07018)

摘　　要：空间机器人在抓握物体时,末端执行器与目标物体之间因接触碰撞而产生的扰动力可能会造成机械臂抖动和位姿改变,甚至将目标物体弹出捕获区,造成捕获失败.针对这一问题,首先介绍了哈尔滨工业大学(HIT)自行研制的三于指空间机器人末端执行器,对末端执行器抓握目标物体过程中的碰撞扰动力进行了分析,提出了一种柔顺抓握策略以削弱抓握目标物体时产生的碰撞扰动力,并设计了一种新的基于前馈补偿和模糊滑模相结合的控制器.末端作用器自身结构的相关量、确定性扰动以及摩擦力的线性部分等可以通过数学建模和离线实验测量得到,通过前馈补偿进行有效控制;对于摩擦非线性部分、未知扰动、于指抓握时的碰撞力等不确定量,引入模糊控制规则对其进行补偿.采用HIT在轨自维护机械臂和三手指空间机器人末端执行器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.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 will lead to the failure of capturing operation.To solve this problem,the design of three-fingered space robot end-effector of Harbin Institute of Technology（HIT） is introduced firstly,and then the disturbance force produced by interactive collisions during the progress of grasping a target object is analyzed.A compliant grasp strategy is proposed to weaken the interactive collisions disturbance force,and a new structure of controller based on the combination of feed-forward compensation and fuzzy-sliding mode control is proposed.The deterministic disturbance,the linear part of the friction,and the part associated with end-effector＇s structure itself can be gained by modeling and off-line testing,which can be controlled effectively by feed-forward compensation,and the fuzzy mode control rules can compensate the external uncertain disturbance,nonlinear part of friction,grasp force and so on.Using satellite on-orbit self-servicing manipulator and three-fingered space robot end-effector designed by Harbin Institute of Technology,some grasp experiments are performed on micro-gravity platform. Experimental results show that the proposed strategy and the designed controller can effectively eliminate the disturbance force during grasping.

关 键 词：空间机器人 柔顺抓握 交互碰撞 扰动力 三手指末端执行器 

分 类 号：TP242[自动化与计算机技术—检测技术与自动化装置]