Piezo-driven precision positioning platforms with large stroke are greatly demanded in both scientific research and industrial applications. Although various principles have been proposed to design piezo-driven positioning platforms, the problem of backward motion commonly exists, greatly hindering their applications. To suppress the backward motion, in this paper, an idea by generating a forward frictional force to balance the reversed frictional force was proposed. Correspondingly, a specific arc-shape flexure hinge was designed to generate the forward frictional force via its elastic recovery. To verify the feasibility of the proposed idea, a positioning platform with alterable initial gap between contact surfaces was designed by the parasitic motion principle (PMP). By measuring the output displacement under various initial gaps, a critical initial gap was identified, at which the positioning platform could output stepping displacement without backward motion. Under this critical initial gap, effects of driving voltage and frequency on the backward motion were further investigated. In addition, the natural frequency and loading capacity of the positioning platform were tested. This study confirms that using PMP, it is feasible to design piezo-driven positioning platforms with completely suppressed backward motion, which would enhance the applications of the PMP and PMP positioning platforms.

Impact inertial piezoelectric actuators are favored with their simple control and structure, high resolution, etc. However, achieving a high thrust–weight ratio remains a challenge due to the positive correlation between the thrust force and inertial mass. To address this issue, an impact inertial piezoelectric actuator driven by coupling the inertial force and friction force is proposed in this article. Then, the corresponding structural design, operating principle, force analysis of the motion process, and parameter determination of the actuator were discussed in detail. An actuator prototype with the size of 32 × 29.4 × 6 mm ³ and mass of 8.2 g was manufactured, and a series of tests were performed under various preload deformations, voltages, frequencies, and loads. The experimental results showed that the actuator driven by coupling the inertial force and friction force could effectively enhance the thrust–weight ratio, and it achieved a maximum thrust–weight ratio of 54.42, far surpassing other actuators of the same type. Meanwhile, the actuator exhibited a maximum thrust force of 4.46 N, comparable to actuators with larger inertial masses. Furthermore, the actuator possessed excellent frequency stability and good adaptability in the motion angle and preload deformation.

In this paper, the self-deformation mode of the stick-slip principle was proposed, and accordingly a piezoelectric actuator based on the self-deformation mode was designed, which could achieve stable bidirectional outputs with long stroke. To increase the stepping displacement of the output end and reduce the structural stress, an arc-shape flexible hinge with variable section was employed as the output part of the flexible hinge mechanism. The self-deformation motion was obtained by the deformation of the driving mechanism caused by the reaction force of the mover in the driving process. The stepping and self-locking characteristics of the actuator under various initial gaps were tested, and the evolution of stepping characteristics with the driving voltage, frequency and external load was analyzed. The experimental results showed that by the self-deformation mode, the long stroke with good linearity could be easily achieved for both the forward and reverse motions, and the maximum self-locking force reached 5 N. Furthermore, the maximum driving speed reached 2754 μ m s ⁻¹ under the driving voltage of 120 V.

The angle between the piezoelectric stack (PES) and the mover would significantly affect the output performances of stick-slip piezoelectric actuators in theory; however, this issue has not been explored. Accordingly, in this paper, to investigate the effects of the angle, a stick-slip piezoelectric actuator with a changeable angle between the PES and the mover was proposed, and its structure was briefly introduced first. Then, the relationship between the angle and the parasitic motion was theoretically calculated. After that, the output performances of the actuator were characterized under different angles between the PES and the mover. The results indicated that the angle between the PES and the mover significantly affected the one-step maximum displacement and the backward motion. After comprehensive analysis, the best output performances of the actuator were obtained under the angle of 0°.