Design and research of a piezoelectric-hydraulic hybrid actuation system with a half-wave resonator

A novel piezoelectric-hydraulic hybrid actuation system with a half-wave resonator is proposed in this paper to generate high-frequency, high-pressure liquid flow and mechanical output through liquid resonance. The new hybrid actuator is similar to the traditional hybrid actuator, with the main difference being the pump chamber itself. The length of the specially designed pump chamber is greater than that of the traditional pump chamber, which facilitates resonance by virtue of the compliance and inertia of the liquid. Once the excitation frequency approaches the resonant frequency of the liquid in the pump chamber, the pressure in the pump chamber will be higher than that under quasi-static conditions, and the output of the hybrid actuator will benefit from it. The compositional structure and working principle of the new hybrid actuator are presented, and its output performance is experimentally studied. When the voltage is 400 V_p-p and the frequency is approximately 2.44 kHz, the actuator can output a maximum no-load velocity of 5.4 mm/s and a maximum blocking force of 181 N. This strategy verifies the feasibility of using liquid resonance for actuation and realizes high-frequency excitation of the hybrid actuator, which also provides a reference for future research on high-frequency hybrid actuators.