Acceleration control of stacked piezoelectric actuator utilizing disturbance observer and reaction force observer

Stacked piezoelectric actuators are suitable for micro manipulation since it has a high positional resolution and large generative force. However, it is difficult to control acceleration of piezoelectric actuator because of its hysteresis characteristic and spring characteristic. Therefore in this paper, piezo disturbance observer (PDOB) is proposed. Because PDOB treats hysteresis characteristic and spring characteristic as disturbance and compensates these elements, acceleration control is achieved. In addition, piezo reaction force observer (PRFOB) is proposed. By eliminating spring force from disturbance, PRFOB estimates the reaction force without utilizing any force sensors. Validities of PDOB and PRFOB are verified by experiments. Finally, experiment of micro-macro bilateral control (MMBC) constructed a master system and slave system is performed. The master system is a linear motor with conventional disturbance observer (DOB) and reaction force observer (RFOB). The slave system is a stacked piezoelectric actuator with PDOB and PRFOB. It achieved MMBC between a linear motor and a piezoelectric actuator.