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A high torque to weight ratio robot actuator*

Published online by Cambridge University Press:  09 March 2009

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)

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.

Type
Articles
Copyright
Copyright © Cambridge University Press 1995

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References

1.Asada, H. and Youcef-Toumi, K., “Analysis and Design of a Direct-Drive Arm With a Five Bar Link Parallel Drive MechanismASME J. Dynamic Systems, Measurement, and Control 106, No. 3, 225230 (1984).CrossRefGoogle Scholar
2.Legnani, G. and Faglia, R., “Harmonic drive transmissions: the effects of their elasticity, clearance and irregularity on the dynamic behavior of an actual SCARA robotRobotica 10, 369375 (1992).CrossRefGoogle Scholar
3.Luh, J. Y. S., Fisher, W. D. and Paul, R. P., “Joint Torque Control by Direct Feedback for Industrial Robots” Proc. IEEE Conference on Decision and Control, San Diego, CA(1981) pp. 265271.Google Scholar
4.Wu, C. H., “Compliance Control of a Robot Manipulator Based on Joint Torque ServoInt. J. Robotics Research 4, No. 3, 5571 (1985).CrossRefGoogle Scholar
5.Blackburn, J. F., Reethof, G. and Shearer, J. J., Fluid Power Control (Wiley, New York 1960).Google Scholar
6.Maskrey, R. H. and Thayer, W. J., “A Brief History of Electrohydraulic ServomechanismsASME J. Dynamic Systems, Measurement, and Control 100, No. 2, 110116 (1978).CrossRefGoogle Scholar
7.Waldron, K. J., Vohnout, V. J., Pery, A. and McGhee, R. B., “Configuration Design of the Adaptive Suspension VehicleInt. J. Robotics Research 3, No. 2, 3747 (1984).CrossRefGoogle Scholar
8.Wells, D. L., Iverson, E. K., Davis, C. C. and Jacobsen, S. C., “An Investigation of Hydraulic Actuator PerformanceTrade-offs Using a Generic Model” Proc. of the 1990 IEEE International Conference on Robotics and Automation Cincinnati, Ohio, Vol. 3 (1990) pp. 21682173.Google Scholar
9.Parker Hannifin Inc., Hydraulic and Pneumatic Rotray Actuators” Catalog 1800–1 (Cylinder Division, Des Plaines IL, 1985).Google Scholar
10.Merrit, E. H., Hydraulic Control Systems (Wiley, New York, 1967).Google Scholar