Development of a resonant piezohydraulic hybrid actuator

Abstract

This paper proposes a piezohydraulic hybrid actuator driven by a resonant vibrator based on two rhombic micro-displacement amplifiers. The resonant piezohydraulic hybrid actuator consists of a resonant piezoelectric vibrator, a pump body, a manifold, a return valve, and an output cylinder. The vibration mode of the piezoelectric vibrator is simulated, and the working principle of the resonant piezohydraulic hybrid actuator is depicted. Then, the performance of the piezohydraulic hybrid actuator is experimentally investigated, and the effects of exciting frequency, exciting voltage, and bias pressure are analyzed. The results demonstrate that the hybrid actuator performs the best when the exciting frequency is near the resonant frequency; meanwhile, the higher the exciting voltage, the better the performance. Moreover, it indicates that a larger bias pressure will bring a larger reaction force to the vibrator and reduce the performance of the actuator system. The maximum blocked force and no-load velocity are 378 N and 4.8 mm/s, respectively, when the bias pressure is 1.5 MPa and the exciting voltage is 500 Vpp.

Design and development of a piezoelectric-hydraulic hybrid actuator with quarter-wavelength tubes

“…When the excitation frequency is 455 Hz, the output displacement of the new hybrid actuator is relatively uniform, and its corresponding pulsation rate is minimal. Figures 10(c In addition, taking 455 Hz as an example, the hybrid actuator without quarter-wavelength tubes has a reverse displacement at this frequency, which may be caused by insufficient sealing of the valve [24]. The reverse displacement will aggravate liquid flow pulsation and further increase the effect of inertial force on the hybrid actuator.…”

“…When it is opened, the two sides of the hydraulic cylinder are connected, and the hydraulic rod can be reset to the original position for the next experiment. There is an additional threaded hole in the manifold for connection to an external manual hydraulic pump, which can fill the system with liquid and bias it to act as an accumulator [24]. Two threaded holes are designed on the hydraulic cylinder for connecting pressure gauges, and there are also two vents for exhaust gas, as shown in figure 2(a).…”