Mechanical modulations for enhancing energy harvesting: Principles, methods and applications

Precision positioning systems with large working stroke (millimeter or more) and micro/nano-scale positioning resolution are widely required in both scientific research and industries. For this kind of applications, piezoelectric materials based actuators show unique advantages and have been widely employed. To overcome the demerit of the limited working stroke for single piezoelectric element, various stepping motion principles have been proposed in the past years, and accordingly, stepping piezoelectric actuators with various structures have been designed and evaluated. This review is aimed to summarize the recent developments and achievements in stepping piezoelectric actuators with large working stroke. Especially, the emphasis is on three main types of stepping piezoelectric actuators, i.e., inchworm type, friction-inertia type, and parasitic type. The motion principles of these three types of piezoelectric actuators and the corresponding developments of various actuators are discussed respectively, followed by pointing out the existing problems in these three types of piezoelectric actuators and proposing some potential research directions in this topic. It is expected that this review is helpful for relevant researchers to understand stepping motion principles as well as piezoelectric actuators, and to successfully select and design stepping piezoelectric actuators for specific applications.

Stepping piezoelectric actuators with large working stroke for nano-positioning systems: A review

A trapezoid-type stick–slip piezoelectric linear actuator using a right circular flexure hinge mechanism was proposed, designed, fabricated, and tested with the aim of accomplishing linear driving based on stick–slip motion. The angle adjustment of the trapezoid beam was used for generating lateral motion on the driving foot of the flexure hinge mechanism. A method of tuning the lateral motion of the flexure hinge mechanism was discussed. Based on the finite-element method, a proper angle of the trapezoid beam was obtained. The analysis results proved that asymmetrical flexure hinge mechanism can increase static friction force in slow extension stage and decrease kinetic friction force in quick contraction stage by lateral motion of the driving foot. A prototype was fabricated and its experimental system was established. The mechanical output experiments showed that the prototype achieved maximum output velocity and load of 5.96 mm/s and 3 N at a voltage of 100 V $p-p$ and a frequency of 500 Hz, respectively.

A Novel Trapezoid-Type Stick–Slip Piezoelectric Linear Actuator Using Right Circular Flexure Hinge Mechanism

A review of recent studies on non-resonant piezoelectric actuators

A survey of piezoelectric actuators with long working stroke in recent years: Classifications, principles, connections and distinctions

Study on a piezo-windmill for energy harvesting

A novel piezoelectric inchworm actuator driven by one channel dc signal is developed in this article to simplify excitation signal of the inchworm actuators, and the clamping force of the developed actuator is generated by a dc motor and two permanent magnets. The piezoelectric stack is excited by a sensing signal, which is generated by the separate photoelectric sensor to detect the position of the rotational permanent magnets. A mathematical model is established to predict the motion of the slider. The prototype of the proposed piezoelectric actuator is fabricated, and mechanical output performance is measured. At a voltage of 75 V and frequency of 3.2 Hz, the average output step is 0.241 μ m under no-load conditions. The proposed inchworm actuator can be operated by just one channel dc signal and the output displacement is stable, which provides a new idea for the integration design of the piezoelectric actuators in the future.

A Novel Piezoelectric Inchworm Actuator Driven by One Channel Direct Current Signal

A low-frequency structure-control-type inertial actuator using miniaturized bimorph piezoelectric vibrators is proposed in this paper to achieve high resolution and high stability with a large linear stroke. These vibrators are fabricated by bonding, thinning, and patterning fabrication processes, which are beneficial to realize miniaturization and increase output performance for the system. A theoretical model based on work-energy analysis is established to predict the output displacement characteristics. An experimental system is built to evaluate the performance of the proposed actuator. Experimental results indicate that the stable minimum step displacement is 0.03 μm under a square wave signal of 5 V, 50 Hz, and a clamping difference of 3.5 mm. Under the condition of 7 V and 50 Hz, the sample standard deviation is 0.0337 μm in repeatability test. The proposed actuator achieves a stable and accurate linear bidirectional motion with high resolution, high stability, low power consumption, and a large working stroke.

A Low-Frequency Structure-Control-Type Inertial Actuator Using Miniaturized Bimorph Piezoelectric Vibrators

A self-adapting linear inchworm piezoelectric actuator based on a permanent magnets clamping structure

This paper presents innovative piezoelectric inertial rotary actuators based on asymmetrically clamping structures, which apply magnetic force to improve driving performance. By using a pretightening force control device, the designed actuators can realize high accuracy and stability. To test the influence of magnetic force on the driving property, two types of actuators are fabricated and investigated. Piezoelectric-driven force is the only driving source of the first actuator type, whereas magnetic force is applied to the second actuator type. An experimental system is built to test the performance of the actuators under different frequencies, voltages, and pretightening torques. Experimental results indicate that the stable minimum output stepping angle is 0.85 μrad under a square signal of 20 V, 6 Hz and a pretightening torque of 2.475 N mm. Under the condition of 8 Hz and 100 V, the maximum angle velocity and output force can reach 4.02 rad/s and 0.98 N, respectively. The proposed actuators not only achieve a stable and accurate rotary motion but also realize a large output force and a fast velocity, thus contributing to the application of pretightening force control device and magnetic force.

Jianming Wen

Papers

Study on a piezo-windmill for energy harvesting

A Novel Piezoelectric Inchworm Actuator Driven by One Channel Direct Current Signal

A Low-Frequency Structure-Control-Type Inertial Actuator Using Miniaturized Bimorph Piezoelectric Vibrators

A self-adapting linear inchworm piezoelectric actuator based on a permanent magnets clamping structure

Piezoelectric inertial rotary actuators based on asymmetrically clamping structures