The Application of Gain Scheduling to High Speed Independent Drives

RW Beaven, MT Wright, SD Garvey (Aston University), MI Friswell (University of Wales Swansea) & DR Seaward (Molins plc)

Control Engineering Practice, Vol. 3, No. 11, November 1995, pp. 1581-1585

Abstract

Independent drives are increasingly being used to replace traditional mechanical linkages, such as gears or belts, on high-speed machinery for numerous reasons including increased reliability, increased manufacturing flexibility and reduced cost. For independent drives to give comparable performance to mechanically coupled systems, advanced control techniques have to be employed, to compensate for the inherent lack of stiffness in servo motor air gaps. This paper discusses the application of set-point gain scheduling to high-speed independent drive systems. Set-point gain scheduling involves switching between separate controllers at setpoints within the event cycle in order to improve performance as measured by a particular error law (in this case the time taken to settle within a positional error band). Its use is demonstrated on an industrial design problem, both in a non-linear simulation and on a corresponding test rig. The results are compared to non-varying controllers based on PID with velocity feedforward and a H infinity-norm optimisation technique and show that a dramatic reduction in cycle time is possible. The industrial problem involves the indexing of a 2x10^-4 kgm^2 inertial load through 70 degrees in 20 milliseconds or less with an endpoint accuracy of +/-10 by a motor whose rotor inertia 8.3x10^-5 kgm^2.

Paper Availability

This material has been published in the Control Engineering Practice, Vol. 3, No. 11, November 1995, pp. 1581-1585, the only definitive repository of the content that has been certified and accepted after peer review. Copyright and all rights therein are retained by Elsevier. This material may not be copied or reposted without explicit permission.


Link to paper using doi:10.1016/0967-0661(95)00168-T

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