Joint Position Command-based Variable Impedance Control of Robot Arm for Human-Robot Cooperation Task

• Main Authors: Cheng-Chin Chen, 陳正欽
• Other Authors: Shih-Hsuan Chiu
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/95650861640644886689

博士 === 國立臺灣科技大學 === 自動化及控制研究所 === 103 === Point-to-point motion of an industrial robot arm is usually realized by position control. However, sometimes it is necessary for the robot to perform tasks in interaction with the environment such as assembly tasks. Therefore, compliant motion control is necessary. An impedance control is a critical technology for compliant motion control. However, the dynamic model of the robot arm is extremely complicated and computationally time consuming. To implement impedance control within the dynamics of the robot is difficult. Indeed, industrial robots perform tasks by position control. In this thesis, a strategy of joint position based-command impedance control for the robot arm is proposed. When the robot arm executes the cooperation task with human, the force sensor is usually installed at the wrist of the robot arm to measure the force/moment caused by the external force and the load (the end-effector and the extra object). The robot arm will perform the wrong compliant motion exerted by the load. The load compensation method can successfully remove the effect caused by the load, and the robot arm performs compliant motion correctly, in accordance with the external force. Besides, in order to improve the performance of the compliance ability for human-robot cooperation, joint position based-command variable impedance control is proposed. The proposed method can adjust impedance parameters to change the compliance of the robot arm by estimating the intention of the operator. Experiment results illustrate that the operator guides the robot arm more quickly and more labor-saving.