Dynamics and Control of a Robotic Wrist with Two Collocated Axes of Compliant Actuation

• Main Authors: Jia-YouXu, 徐嘉佑
• Other Authors: Chao-Chieh Lan
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/z596e7

碩士 === 國立成功大學 === 機械工程學系 === 102 === This research presents the controller design of a novel compliant robotic wrist. Unlike traditional wrist mechanisms that consist of series of rotary motors with bulky gear trains, the proposed design consists of two linear step motors with lead crew to amplify the output force. The linear motions are transmitted to the output pitch and yaw rotations through slider crank and spherical mechanisms. The proposed design simultaneously achieves dexterity and high torque density. The size, range of motion, and weight of the proposed wrist are comparable to those of a human wrist. Inspired by human wrists, the proposed wrist employs two linear compliant couplers to achieve two collocated and perpendicular axes of compliant actuation. Compared with traditional stiff actuation, compliant actuation has lower mechanical impedance, higher safety and can easier achieve high-quality force control. Compliant actuation is commonly used in biomimetic mechanisms, exoskeletons, and service robots. This research first presents the mathematical model and parameter identification of step motors. Next, the static and dynamic models of the proposed wrist are developed. The models serve as the basis of controller design. The presented controller design includes force and position control. The controller performance is verified by comparing experiment and simulation results. Through a prototype demonstration, the wrist is expected to serve as an alternative for applications involving human-robot interaction.