Force and Position Control for Self-Adaptive Three-Finger Gripper

• Main Authors: Yi-Cheng Lin, 林羿丞
• Other Authors: Tsu-Tian Lee
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/18545532878512913149

碩士 === 淡江大學 === 電機工程學系碩士班 === 104 === A design and implementation method of a self-adaptive three-finger gripper is proposed in this thesis. There are two methods, one is the gripper mechanism and the other is the gripper control. In the gripper mechanism design of this self-adaptive three-finger gripper, an underactuated mechanism with a self-adaptive finger is designed so that it can change the shape of three-finger to grip the object based on its shape. In the gripper control, two control types are proposed. One is a position control and the other is a force control. In the position control, a fuzzy PID control based on the motor current position obtained by a motor encoder is proposed to control the grabbing and loosening status of gripper. It can adjust the appropriate gesture in advanced according to the shape and size of object to eliminate the grabbing and loosening period of the gripper. In the force control, a fuzzy controller based on the current obtained by a current sensor is proposed to determine a rotational speed of the brushless DC motor to control the tightness of the gripper while this gripper is grabbing. According to the feedback to compute the displacement after the motor contacts the object, it can corroborate the tightness when the object is grabbed. The more amount of the displacement the tighter the gripper grabs the object. Some experimental results are presented to illustrate the proposed two control types can let the gripper can effectively grab objects.