The majority of feedback systems driven by an electric motor can be represented by a two-mass system connected via a flexible drive element. Owing to the presence of backlash, the closed-loop performance such as precision speed, position and force control that can be achieved using a linear time invariant controller is limited, and it is expected that a nonlinear control would be superior. In this paper a nonlinear control structure is proposed and a systematic design technique presented. The advantages of the proposed design technique are: (i) It is robust to plant and backlash uncertainty; (ii) it is quantitative to specifications on the maximum limit cycle amplitude; and (iii) the closed loop is superior to a linear controller design both in lower bandwidth and in lower limit cycle amplitude. A design example is included.

Brandenburg, G., Unger, H., and Wagenpfeil, A., 1986, “Stability Problems of a Speed-Controlled Drive in an Elastic System with Backlash and Corrective Measures by a Load Observer,” Proceedings of the International Conference on Electrical Machines, IEEE, Munich, pp. 523–527.
Brandenburg, G., and Schafer, U., 1989, “Influence and Adaptive Compensation of Simultaneously Acting Backlash and Coulomb Friction in Elastic Two-Mass Systems of Robots and Machine Tools,” Proceedings of the IEEE International Conference on Control and Applications, IEEE, Jerusalem, pp. WA-4–5, 1–3.
Chubb, Bruce, A., 1963, Modern Analytical Design of Instrument Servomechanisms, Addison-Wesley, N.Y.
Gelb, A., 1968, Multiple-Input Describing Functions and Nonlinear System Design, McGraw-Hill, N.Y.
Gutman, P. O., Oldak, S., and Baril, C., 1992, “Quantitative Design of a Class of Nonlinear Systems with Parameter Uncertainty,” Quantitative Feedback Theory Symposium Proceedings, Flight Dynamics Directorate Wright Laboratory Air Force Command Wright-Patterson Air Force Base, OH, pp. 542–564.
Horowitz, I. M., 1992, Quantitative Feedback Design Theory (QFT), QFT Publications, CO.
Jayasuriya, S., 1990, “On the Determination of the Worst Allowable Persistent Bounded Disturbance for a System with Constraints,” Proceedings of the 1990 American Control Conference, IEEE, San Diego, CA, pp. 605–610.
Jayasuriya, S., and Franchek, M. A., 1988, “Frequency Domain Design for Prespecified State and Control Constraints under Persistent Bounded Disturbances,” Proceedings of the 27th IEEE Conference on Decision and Control, IEEE, Austin, Texas, pp. 1748–1753.
Peschon, J., 1965, Disciplines and Techniques of Systems Control, Blaisdell Publication, N.Y.
Cook, P. A., 1986, Nonlinear Dynamical Systems, Prentice-Hall, International Series in Control Engineering.
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