Scaling of Direct Drive Robot Arms

This article studies the ways that the performance of direct drive (DD) serial robots changes as system size is changed. We are particularly interested in the physical laws for scaling down direct drive arms to small sizes. Using theoretical scaling analysis, we show that there is a net physical performance advantage to small direct drive arms. A key factor for direct drive robot performance is the torque-to-mass ratio of the actuators, U. We show how U varies with the scale of DD actuators, and we also calculate how the dynamic performance varies with scale and U. We compare our calculations with experimental measurements of actuators of various sizes taken from small hard disk drives and compare them with published data for larger motors. Finally, we describe a prototype, five- axis, direct drive serial arm having a reach of 10 cm and a work volume of about 136 cm3. Some potential applications are briefly discussed.

[1]  Hisato Kobayashi,et al.  A scaled teleoperation , 1992, [1992] Proceedings IEEE International Workshop on Robot and Human Communication.

[2]  Blake Hannaford,et al.  Modeling and stability analysis of a scaled telemanipulation system , 1994, Proceedings of 1994 3rd IEEE International Workshop on Robot and Human Communication.

[3]  H. Harry Asada,et al.  Direct-Drive Robots: Theory and Practice , 1987 .

[4]  B. Hannaford,et al.  The anthroform neural controller: a system for detailed emulation of neural circuits , 1992, [Proceedings] 1992 IEEE International Conference on Systems, Man, and Cybernetics.

[5]  D'arcy W. Thompson.  On growth and form i , 1943 .

[6]  Oussama Khatib,et al.  The robotics review 1 , 1989 .

[7]  Septimiu E. Salcudean,et al.  Towards a Force-Reflecting Motion-Scaling System for Microsurgery , 1994, ICRA.

[8]  Blake Hannaford,et al.  A 5-axis mini direct drive robot for time delayed teleoperation , 1994, Proceedings of IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS'94).

[9]  R. M. Alexander.  How Dinosaurs Ran , 1991 .

[10]  Blake Hannaford,et al.  Kinesthetic Feedback Techniques in Teleoperated Systems , 1991 .

[11]  Edward V. Lewis,et al.  Principles of naval architecture , 1988 .

[12]  John M. Hollerbach,et al.  The McGill/MIT direct drive motor project , 1993, [1993] Proceedings IEEE International Conference on Robotics and Automation.

[13]  Michael Levin,et al.  The design and control of an experimental whole-arm manipulator , 1991 .

[14]  J. Edward Colgate.  Power and impedance scaling in bilateral manipulation , 1991, Proceedings. 1991 IEEE International Conference on Robotics and Automation.

[15]  John J. Craig,et al.  Introduction to Robotics Mechanics and Control , 1986 .

[16]  Homayoon Kazerooni,et al.  Statically balanced direct drive manipulator , 1989, Robotica.

[17]  Takeo Kanade,et al.  Design of Direct-Drive Mechanical Arms' , 1983 .

[18]  B. Hannaford,et al.  Mini direct drive robot arm for biomedical application , 1991, Fifth International Conference on Advanced Robotics 'Robots in Unstructured Environments.

[19]  Willoughby.  Reliability by Design , 1978 .

[20]  Richard S. Wallace.  Miniature direct drive rotary actuators , 1993, Robotics Auton. Syst..

[21]  Oussama Khatib,et al.  New robot mechanisms for new robot capabilities , 1991, Proceedings IROS '91:IEEE/RSJ International Workshop on Intelligent Robots and Systems '91.

[22]  Blake Hannaford,et al.  MICROTREX: MICRO-TELEROBOTIC FLIGHT EXPERIMENT , 1994 .

[23]  Blake Hannaford,et al.  The anthroform neural controller: An architecture for spinal circuit emulation , 1992, 1992 14th Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[24]  Pradeep K. Khosla.  Some experimental results on model-based control schemes , 1988, Proceedings. 1988 IEEE International Conference on Robotics and Automation.

[25]  Ian W. Hunter,et al.  A comparative analysis of actuator technologies for robotics , 1992 .

[26]  W. S. Trimmer,et al.  Actuators for micro robots , 1989, Proceedings, 1989 International Conference on Robotics and Automation.