Low-Profile Piezoelectric Inertial Linear Actuator for High-Power Applications

The paper presents the results of numerical and experimental investigations of a novel low-profile piezoelectric inertial linear actuator designed for a high-payload application. The actuator structure is based on a rectangular piezoelectric bimorph plate with centrally located trapezoidal toothed rings. The actuator operates in the second longitudinal vibration mode of the plate, which is excited by a sawtooth electric signal. Trapezoidal teeth are used to transfer longitudinal vibrations of the plate to the slider and, this way, generate linear motion. The use of trapezoidal teeth reduces the stumbling effect at high preload forces and as a result increases the actuator's ability to operate under high preload forces and drive higher payloads. Numerical simulations indicated that the actuator exhibits a resonance frequency of 68.49 kHz, with the trapezoidal tooth achieving a maximum displacement amplitude of 188.25 µm at a voltage of 200 V_p-p. Furthermore, numerical analysis revealed that the trapezoidal tooth deflection in the out-of-plane direction under an axial load of 25 N reached 2.07 nm/N, demonstrating structural stability under high preload conditions. The results of experimental investigations have shown that the actuator can provide up to 75.16 mm/s at a linear motion speed of 200 V_p-p and an output force of 18.88 N at the same excitation signal amplitude. In addition, the 15 N load actuator was indicated to achieve a linear motion accuracy of 11.5 µm per step.