The Force Feedback Control of Robot Arm for Industrial Precision Assembly Tasks

• Main Authors: Kun-Ting Chen, 陳坤廷
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/pfzwqn

博士 === 國立臺灣科技大學 === 材料科學與工程系 === 104 === As the technology of industrial robots develops and improves, industrial robots grow to execute the tasks interacted with environment, such as precise assembly tasks. Under the situation of positioning errors, using a pure position controller to control an industrial robot will cause the irregular impact, and destroy the industrial robot, tools, and the environment. The industrial robots are generally controlled under position mode. In order to utilize the industrial robots to execute the precise assembly task under position mode, this study proposes a strategy which named the variable impedance control with the desired force. This strategy is composed of the joint position based impedance control and the impedance parameters varying method. This strategy appropriately adjusts the position and orientation of the end-effector, and makes the robot compliant to the force/moment which acted by the environment. Using this strategy, the dynamics of the robot does not need to be derived. Therefore, this strategy can be utilized to control any position commanded robot. In addition, in order to correctly estimate external force/moment applied on the end-effector, this study derives the transformation of the force/moment on different coordinate frame. Using this transformation, the force/moment sensed from the coordinate frame of the sensor can be translated to the coordinate frame of the end-effector. The experiments of this study include the fundamental experiment of the transformation of force/moment and peg-in-hole assembly experiments. The fundamental experiment of transformation of force/moment verifies that the transformation of force/moment coordinate frame correctly transforms the reference coordinate frame of force/moment. Moreover, this study utilizes peg-in-hole assembly tasks to verify the impedance control with desired force and the impedance parameters varying method. The results show that the impedance controller with variable parameters is more suitable than one with fix parameters; compared with fix desired force, the variable desired force can decrease the process time of the assembly task. Finally, the proposed method is utilized to implement three peg-in-hole assembly tasks with the different sets of clearance.