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A high torque to weight ratio robot actuator*

Published online by Cambridge University Press:  09 March 2009

James E. Bobrow  and
Jayesh Desai
James E. Bobrow
Affiliation:
Mechanical and Aerospace Engineering, University of California, Irvine, CA 92717 (USA)
Jayesh Desai
Affiliation:
Mechanical and Aerospace Engineering, University of California, Irvine, CA 92717 (USA)
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Summary

A light-weight, high-torque actuator with accurate torque control capability is described. The actuator uses a small hydrostatic transmission to achieve the advantage of large gear reduction from a high speed DC motor, and retains accurate joint torque sensing and control capabilities with no backlash. A disadvantage of the actuator is that is introduces extra dynamics which must be accounted for in robot control systems. It is shown that state feedback enables closed loop control of joint torque, with full back drivability, through an effective gear ratio of 485:1 for the experimental system. The actuator can therefore be used for both position control and output force control, which is essential for modern robot control algorithms. A mathematical model of the system is presented in this paper along with experimental results.

Keywords

Robot actuatorTorque controlHydrostatic transmissionState feedback
Type
Articles
Information
Robotica , Volume 13 , Issue 2 , March 1995 , pp. 201 - 208
Copyright
Copyright © Cambridge University Press 1995

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