A bionic inertial impact piezoelectric actuator with multi-performance improvement

Abstract

Due to the simple structure and ideal step-like motion curve, the inertial impact piezoelectric actuator is considered as a highly promising driving device. However, the existing impact actuators generally adopt a cantilever layout, and the driving force only comes from the inertial mass, resulting in poor output stability and low driving force density. Therefore, a significant improvement in certain performance is often accompanied by a sacrifice of other performances. To achieve a balanced improvement in multi-performance, the co-design for actuator is necessary. Inspired by the body function and structure layout of tadpoles, a novel bionic impact actuator with large force density was proposed. The structure was presented in detail and analyzed through theoretical analysis and finite element simulation. The experimental results indicated that the proposed bionic impact actuator could output a 43.4% larger stepping displacement than that of the traditional one (driven only by the inertial mass), with a speed of 2.9948 mm/s, frequency bandwidth of near 480 Hz, resolution of 30 nm, load capacity of 280 g horizontally and 4000 g vertically. In addition, the actuator had wide environmental adaptability and could work within the initial preload of over 200 µm and the tilt angle of ±15°. It also had excellent output retainability under low voltages or high frequencies, which facilitated subsequent linear control. The experimental and comparative results demonstrated that the balanced multi-performance improvement of inertial impact actuators was realized by the bionic design. Besides, this bionic scheme had some universality and could be used to improve the performances of other impact actuators.