<title>Control of a hysteretic actuator using inverse hysteresis compensation</title>

Abstract

The accurate control of a system that exhibits hysteresis requires a control strategy that incorporates some form of compensation for the hysteresis. One approach is to develop an accurate model P of the hysteresis and then use the inverse P<SUP>-1</SUP> as a compensator (inverse compensation). This paper focuses on the problem of determining P and P<SUP>-1</SUP> for a piezoelectric stack actuator. The KP operator is used to formulate the hysteresis operator P and from this an approximation P<SUB>m</SUB> is derived. Compensation is then defined in terms of the inverse of the approximation, P<SUB>m</SUB><SUP>-1</SUP>. Experimental data collected on an unloaded piezoelectric stack actuator is used to demonstrate the concept of inverse compensation. The parameters of P<SUB>m</SUB> are identified using only major hysteresis loop data and results are given that show P<SUB>m</SUB> provides an accurate model for both major and minor hysteresis loops. Results are then presented that demonstrate the capability of the inverse P<SUB>m</SUB><SUP>-1</SUP> to compensate for the actuator hysteresis.