Numerical Analysis and Experimental Investigation of a Piezoelectric-Hydraulic Hybrid Actuator With Two Thin Plate Resonators

The conventional piezoelectric-hydraulic hybrid actuator consists of a hydraulic pump driven by a piezoelectric stack along with a hydraulic cylinder and is envisioned as a potential actuator for a trailing edge flap on a full-scale smart rotor system. For this type of actuator, the inertial force caused by the flow pulsation of the liquid will significantly degrade its output performance. To solve these issues, two thin plates connected with counterweights are embedded in the hybrid actuator to act as two mechanical band-stop filters, and its working principle is illustrated by the mechanic-electric-hydraulic analogy. Its configuration is presented in detail, and the output performance is tested. The experimental results show that when the excitation frequency is close to the resonance frequency of the mechanical filter in the hydraulic system, the pulsation rate is reduced, the influence of the inertial force on the actuator is weakened, and its output performance is relatively significantly enhanced. The maximum velocity of the new hybrid actuator with a blocking force of 125 N has been increased from 27.3 to 48 mm/s. This strategy has proven effective for piezoelectric-hydraulic hybrid actuators and can be adopted by many other electrohydraulic actuators for performance improvement.