Multi-DOF Ultrasonic Actuators for Laser Beam Positioning

Ramutis Bansevicius,Vytautas Jurenas,Asta Drukteiniene,Genadijus Kulvietis,Dalius Mazeika

doi:10.1155/2019/4919505

Ramutis Bansevicius, Vytautas Jurenas + Show 3 more

Open Access

https://doi.org/10.1155/2019/4919505

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Abstract

A novel design concept of multi-degree-of-freedom (multi-DOF) piezoelectric actuator is introduced in the paper. The main idea is to connect two identical piezoelectric transducers by hyperelastic material in order to increase the total number of degrees-of-freedom of the system. Such design principle also allows to separate vibrations of two piezoelectric transducers and to control them independently. The ring- and cylinder-type piezoelectric transducers were used to design two multi-DOF ultrasonic actuators for precise laser beam positioning. Reflecting mirror is mounted on the top of the actuator and is preloaded by magnetic force. Both disc- and cylinder-type actuators can realize up to six degrees-of-freedom, i.e., to rotate the mirror about three axes employing one transducer and to position mirror in the plane by using another transducer. Bidirectional rotation and translation motion of the mirror are obtained by switching excitation signals between different electrodes of the transducers. Both the numerical simulation and physical prototype were used to verify operating principle of the actuators. Numerical investigation of the piezoelectric actuator was performed to investigate modal-frequency and harmonic response analysis while experimental study was performed to measure electrical and mechanical output characteristics of the piezoelectric actuator. A mathematical model of contacting force control was proposed, and numerical verification was performed when the mirror need to be rotated according to the specific motion trajectory.

Highlights

Laser optical subsystems are used for different applications such as measurement device, industrial machining tools, and robotics [1]
Ability to adjust the laser beam pointing is crucial for the optical system [2]
Micrometer scale resolution is required for the most applications; the higher resolution allows achieving the higher precision of the measurement device or machining tool [3]

Summary

Introduction

Laser optical subsystems are used for different applications such as measurement device, industrial machining tools, and robotics [1]. A similar ultrasonic motor capable of generating a multi-DOF rotation of a spherical rotor utilizing bending and longitudinal natural vibration modes of a barshaped stator was proposed by Tukemura et al [8]. E ring- and cylinder-type piezoelectric transducers are used to design two multi-DOF ultrasonic actuators for precise laser beam positioning applying the proposed design principle. Both ring- and cylinder-type actuators can realize up to six degrees-offreedom, i.e., to rotate the mirror about three axes using the first transducer and to position mirror in the plane employing the second transducer. Numerical simulation and experimental measurements have been performed to verify operating principle and output characteristics of the actuator. e results of numerical and experimental investigations are discussed

Design Concept and Operating Principle

Modeling of the Actuators

Findings

Experimental Study