Hydraulic Actuators Driven by Piezoelectric Elements (1st Report, Trial Piezoelectric Pump and Its Maximum Power).

摘要

This paper daels with the maximum output power of a trial piezoelectric pump as a first step in developing small-sized hydraulic actuators for robots and mechatronic devices, where the main parts of the pump are inlet . outlet valves, connective pipes between the valves and the pressure chambers, and a diaphragm driven by a multilayered piezoelectric element of 22 mm diameter, 55.5 mm length and 170 g mass. The experimental results show that the pumping power takes a maximum value when the driving frequency coincides with the resonant frequency of the working liquid in the pipes, and that the maximum pumping power is 34 W for the pipes with 300 Hz resonant frequency. On the other hand, theoretical consideration of optimal driving of the piezoelectric element indicates that the above pumping power is increased by 70% using appropriate resonant pipes and a pumping chamber of piston-cylinder type instead of the diaphragm.