面向柔软物体抓取的遥操作工程机器人位置反力控制

为改善工程机器人系统的操作性,并提高在抓取和搬运柔软物体过程中的安全性,对主从遥操作系统的控制进行了研究,提出了位置速度/位置反力混合控制的方法。工程机器人在自由移动时,采用位置速度控制,工程机器人与环境间产生反馈力时,切换到位置反力控制。利用反馈力作为反馈信号,实现对力的间接控制。设计并开展了抓取与搬运柔软物体的实验,并对抓取和搬运过程中的物体最大变形量以及活塞杆平均位移进行了统计分析及配对t检测。结果表明:相比传统的位置速度控制方法,位置反力控制方法能够改善主从遥操作系统的操作性,确保在抓取和搬运过程中柔软物体的安全性。

Position Reaction Force Control of Teleoperation Construction Robot for Grasping Soft Objects

In teleoperation, it is very important to ensure that task objects are not severely grasped in grasping and conveying processes. A master-slave system for a teleoperation construction robot employed an excavator with four degrees of freedom (swing, boom, arm and fork glove) as slave and two joysticks with force feedback as master was established. Since the fork glove was regarded as the hand of the robot, the control for the fork glove was the focus. A position velocity control system was previously proposed, and it was found that soft objects were severely crushed in grasping and conveying processes at slow speed. To solve this problem, a position reaction force control method, in which reaction force to the joystick was used as feedback instead of piston velocity, was proposed to improve the controllability. The position velocity control was adopted when the construction robot moving in free space and the position reaction force was introduced when reaction force generated in the grasping process. Grasping experiments were conducted using a tin and urethane foam blocks as task objects by human and control PC at slow velocity, and the experimental results confirmed the validity of the position reaction force control method during slowly grasping of a fragile or soft object. In addition, conveying experiments, which simulated transformation task in practical use by using a tire, a piece of urethane foam and a piece of sponge foam as task objects, were conducted by the position velocity and position reaction force control methods. Experimental and statistical analysis results proof that position reaction force control method is valid to safely transfer soft objects in teleoperation work and it can improve the controllability of the construction robot.