A single-foot linear piezoelectric actuator is proposed in this paper, and a new exciting method for the stepping motion is discussed. The proposed actuator works in the hybrid modes of the second horizontal bending vibration and the second vertical bending vibration. Two intermittent sinusoidal signals with a phase difference of 90° are applied on the horizontal and vertical PZT elements, respectively, to obtain a discontinuous elliptical motion at the driving foot, which can move the runner linearly step by step. The structure of a single-foot linear piezoelectric actuator is designed and the mechanism for the linear driving is clarified. Then, modal and transient analyses are carried out by using ANSYS software to get the resonance frequencies of the bending modes and the movement trajectory of the driving foot. Finally, a prototype of the piezoelectric actuator is fabricated, and experiments are carried out. The experiment results show that the displacement resolution, the maximum velocity, and the maximum thrust of the proposed piezoelectric actuator are about 0.21 μm, 827.5 mm/s, and 27 N, respectively.

A non-resonant-type piezoelectric motor with a precise driving ability was proposed. The operating principle of the proposed motor is different from the previous non-resonant piezoelectric motors using either the clamping and feeding mechanism (inchworm mechanism) or the inertia drive mechanism. An oblique linear motion formed by the hybrid of two bending motions of a sandwich transducer was used to push the runner step-by-step. Two square-wave voltages were applied to the horizontal and vertical PZT elements to obtain the desired oblique linear motion. The mechanism of the proposed piezoelectric motor was illustrated in detail. Then, transient analyses were performed by ANSYS software to simulate the motion trajectory and to find the response characteristics of the motor. Finally, a prototype was fabricated to verify the mechanism and to test the mechanical output characteristics of the proposed motor. Under the input square-wave voltages of 500 Vp-p, the prototype achieved a step displacement of 5.96 μm, a maximum no-load velocity of 59.64 μm/s and a maximum thrust of 30 N. This paper provides a new mechanism for the design of a non-resonant piezoelectric motor with long stroke and precise driving ability.

A planar piezoelectric actuator with large travel range is presented in this paper. The actuator is composed of four uniform piezoelectric transducers, and each transducer can bend along the horizontal direction or vertical direction independently. Trapezoidal-wave signals are used to excite the hybrid bending of the transducers and form rectangular movements on their driving feet. The actuator can move step by step by the static friction forces in nonresonant mode, and a long reliability life is obtained as there is no wear and tear problem. The operating principle is simulated by finite-element method, which reveals the generation of rectangular trajectory on each driving foot and the large structure stiffness of the actuator. A prototype is fabricated and its experiment system is established. A resolution of 16 nm is achieved at the quasi-static mode, a minimum step distance repeatability error rate of 1.06% is obtained at the stepper mode; the maximum output speed and carrying load of 300 μm/s and 35 kg are achieved at voltage of 400 V _p-p and frequency of 40 Hz. The experiments also shows that the output speed is linearly related to the exciting voltage; the motion along any direction in the platform is achieved by controlling the voltage signals.

The inchworm piezoelectric actuator has a wide application prospect in the field of precision instruments. However, in view of the complex structure of the existing inchworm piezoelectric actuator and the far distance between the driving feet of the actuator, it is difficult to realize alternate driving and the high output speed of the driving feet, etc. In this paper, an inchworm piezoelectric linear actuator based on two-stage amplification mechanism is designed, which amplifies the output displacement of the driving feet by two-stage amplification mechanism, and improves the driving efficiency of the actuator stator by the way of alternating driving. We present an inchworm piezoelectric actuator with three piezoelectric stacks and a two-stage amplification mechanism, which is simple in structure design, compact in actuator structure and easy to realize alternate driving. The kinematics and dynamics models of the inchworm piezoelectric actuator are established by analyzing the flexible hinge and its structure with the pseudo-rigid body method. The length of the lever structure and the angle of the triangular structure of the piezoelectric actuator are solved by kinematics, and the natural frequency of the whole structure is calculated by dynamics. Through finite element analysis, the simulation magnification ratio of the piezoelectric actuator is obtained, so as to evaluate and verify the theoretical calculation and further optimize the structure. The experimental results show that the inchworm piezoelectric linear actuator using two-stage amplification mechanism has a high driving speed of 5.53 mm s⁻¹ under voltage of 135 V and frequency of 70 Hz.