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Nano-precision positioning of GMA based on modified Preisach model

Giant magnetostrictive actuators (GMA) are widely applied in ultra-precision positioning. However, the accuracy of GMA in positioning is intensively affected by hysteresis and nonlinearity of giant magnetostrictive materials. To characterize the hysteresis and nonlinearity, The nonlinear model of GMA based on modified Preisach model was established in this paper. Since the operation of Preisach model depends on the previous experimental data and the inversion algorithm of Preisach operators, which is always a complicated procedure, we proposed in this paper a point-standard iterated algorithm instead of the inversion of Preisach operators, in which the extremum values of Preisach model are stored in input memory matrix, and the input current can be determined by the comparison between target value and the current status of displacements. To conduct experiments with GMA under constant temperature, we designed a new actuator with double liquid-cooling structure. Experimental results showed that ultra-precision positioning in open loop with high accuracy and quick response can be realized based on the modified Preisach model and the point-standard iterated algorithm with our novel GMA structure.