Hysteresis modeling and precision trajectory control for a new MFC micromanipulator

This paper presents the development, hysteresis modeling and precision trajectory tracking control of a new micromanipulator based on the macro-fiber-composite (MFC) actuator. As the MFC actuator consists of rectangular piezo ceramic fibers embedded in layers of epoxy and covered by interdigitated electrodes on both sides, the MFC actuator has several merits including the flexible nature, large output displacements, fast respond and high resolution. Consequently, the MFC micromanipulator exhibits excellent performances of a large output displacement up to 519.6 μm, a high resolution of 0.316 μm, and compact size. By means of the Bouc-Wen approach, the hysteresis model for the micromanipulator is established. Through an improved genetic algorithm, the optimal model parameters for the MFC micromanipulator are identified. In addition, to improve the trajectory tracking performance of the micromanipulator, a practical hybrid control scheme employing a feedforward controller combined with an incremental feedback controller is used. The hybrid control scheme can compensate the displacement hysteresis and eliminate the model errors. A series of experiments and validations were carried out and the experimental results validate the performance of micromanipulator and the effectiveness of the developed hybrid control scheme.