A Dual Stage Low Power Converter Driving for Piezoelectric Actuator Applied in Micro Mobile Robot

Chen Chen,Yanzhang Wang,Meng Liu

doi:10.3390/app8091666

Abstract

Piezoelectric actuators are widely utilized to convert electrical energy into mechanical strain with considerable potential in micro mobile robot applications. However, the use of Pb-based Lanthanumdoped Zirconate Titanates (PZTs) leads to two difficulties in drive circuit design, namely, high voltage step-up ratio and high energy conversion efficiency. When some devices driven by piezoelectric actuators are used in emerging technologies, such as micro mobile robot, to perform special tasks, low mass, high energy density, and high conversion efficiency are strategically important. When these demands are considered, conventional drive circuits exhibit the disadvantages of being too bulky and inefficient for low mass applications. To overcome the aforementioned drawbacks, and to address the need for a piezoelectric bimorph actuator, this work proposed a high step-up ratio flyback converter cascaded with a bidirectional half-bridge stage controlled, via a pulse width modulation strategy, and a novel control method. Simulations and experiments were conducted to verify the ability of the proposed converter to drive a 100 V-input piezoelectric bimorph actuator using a prototype 108 mg (excluding printed circuit board mass), 169 (13 × 13) mm2, and 500 mW converter.

Highlights

Microrobots represent a new type of bionic robots inspired by insects to achieve ultracompact size, high mobility, and remote controllability; these robots have many applications, including those in bioengineering, disaster relief, microsurgery, and surveillance [1,2,3]
The disadvantages of low response rate, small mechanical displacement, and low conversion efficiency limit their applications to micro mobile robots (MMRs)
The main objectives of this study are as follows: (a) To determine the equivalent model parameters based on the impedance characteristics of piezoelectric bimorph actuators; (b) to introduce driving methods and requirements for piezoelectric actuators in MMRs; (c) to describe a circuit topology and its control strategy with low mass, high conversion ratio, high power density, and high efficiency; (d) to present a prototype that is capable of driving piezoelectric actuators; and (e) to observe and analyze the experimental results of the circuit output and displacement of material driving

Summary

Introduction

Microrobots represent a new type of bionic robots inspired by insects to achieve ultracompact size, high mobility, and remote controllability; these robots have many applications, including those in bioengineering, disaster relief, microsurgery, and surveillance [1,2,3]. Micro mobile robots (MMRs) are widely used in environmental monitoring, rescue operations, and agricultural production, due to their high energy efficiency and high mobility. If the energy conversion efficiency of the frame, including the actuator, power circuit design, and mechanical transmission for stroke amplification can be improved, the application prospects of such robots will be extended. Actuators are widely used in many types of micromechanical devices like walking, swimming, jumping robots and so on [4,5,6]. The disadvantages of low response rate, small mechanical displacement, and low conversion efficiency limit their applications to MMRs

Objectives

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Conclusion