Design of Direct-Drive Mechanical Arms

作     者：Asada, Haruhiko Kanade, Takeo 

作者机构：Visiting Research Scientist of Robotics Institute United States Computer Science Department and Robotics Institute Carnegie-Mellon University Pittsburgh PA 15213 Schenley Park United States 

出 版 物：《Journal of Vibration and Acoustics, Transactions of the ASME》 (J Vib Acoust Trans ASME)

年 卷 期：1983年第105卷第3期

页      面：312-316页

学科分类：1002[医学-临床医学] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 0702[理学-物理学] 0801[工学-力学（可授工学、理学学位）] 

主　　题：Design Robots Stress Weight (Mass) Torque Mechanisms Belts Inertia (Mechanics) Design theory Rotors 

摘      要：This paper describes the design concept of a new robot based on the direct-drive method using rare-earth d-c torque motors. Because these motors have high torque, light weight and compact size, we can construct robots with far better performance than those presently available. For example, we can eliminate all the transmission mechanisms, such as reducers and chain belts, between the motors and their loads, and construct a simple mechanism (direct-drive) where the arm links are directly coupled to the motor rotors. This elimination can lead to excellent performance: no backlash, low friction, low inertia, low compliance and high reliability, all of which are suited for high-speed, high-precision robots. First we propose a basic configuration of direct-drive robots. Second a general procedure for designing directdrive robots is shown, and the feasibility of direct drive for robot actuation is discussed in terms of weights and torques of joints. One of the difficulties in designing direct-drive robots is that motors to drive wrist joints are loads for motors to drive elbow joints, and they are loads for motors at shoulders. To reduce this increasing series of loads is an essential issue for designing practical robots. We analyze the joint mass system for simplified kinematic model of the direct-drive robots, and show how the loads are reduced significantly by using rare-earth motors with light-weight and high torque. We also discuss optimum kinematic structures with minimum arm weight. Finally, we describe the direct-drive robotic manipulator (CMUarm) developed at Carnegie-Mellon University, and verify the design theory © 1983 ASME.