Modeling and Control of a Manipulator Joint Driven Through a Worm Gear Transmission

Abstract

The worrnscrew gearset provides a potential advantage for some robot manipulator designs because of its simplicity, compactness, and capacity for large speed-reduction ratios. However, an oscillatory behavior has been observed in such implementations that, depending on the extension and loading of the manipulator, tends to grow as the manipulator is lowered under the influence of gravity and disappears as the manipulator is raised. The oscillations can become quite large, crippling the utility of the manipulator The growing oscillations are indicative of an instability. However, it is not immediately apparent why such a system should be unstable. The objectives of this work were to find the source of the oscillatory behavior and to determine whether feedback control can be employed to stabilize such a system.

Keywords

Control robotics nonlinear systems gearing

Get full access to this article

View all access options for this article.

References

Craig, J.J. , 1989, Introduction to Robotics Mechanics and Control, 2d ed., Addison Wesley, Reading, MA.

May, D.C. , 1990, "Modeling and control of a robot manipulator joint driven through a worm gear transmission," M.S. thesis, Department of Mechanical Engineering, Texas A&M University, College Station.

Meirovitch, L. , 1970, Methods of Analytical Dynamics, McGraw Hill, New York.

Mooring, B.W. , May, D.C. , and Shulte, M.S. , 1990, "Modeling and analysis of a manipulator joint driven through a worm gear transmission," Journal of Mechanical Design 112(4),551-556.

Ogata, K. , 1987, Discrete-Time Control Systems, Prentice Hall, Englewood Cliffs, NJ.

Phelan, R.M. , 1970, Fundamentals of Mechanical Design, McGraw Hill, New York.

Shigley, J.E. , 1977, Mechanical Engineering Design, McGraw Hill, New York.

Smith, J.D. , 1983, Gears and Their Vibration, Marcel Dekker , New York.