Triangular-Shaped 5-DOF Piezoelectric Robot for Optical Lens Positioning

Andrius Čeponis,Vytautas Jūrėnas,Dalius Mažeika

doi:10.3390/app12052498

Andrius Čeponis, Vytautas Jūrėnas + Show 1 more

Open Access

https://doi.org/10.3390/app12052498

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Abstract

The paper represents numerical and experimental investigations on a 5-DOF piezoelectric robot that can provide rotary and planar motions of the payload. The design of the robot is based on a single piezoelectric ring and a triangular-shaped passive layer made from stainless steel. Six semispherical contacts of alumina oxide were used as contact points for rotary and planar motions. Finally, the top electrode of the piezo ceramic ring was divided into six equal segments to control the 3-DOF angular and 2-DOF planar motions of the payload. Two harmonic signals of different frequencies are used to drive the piezoelectric robot. The robot operation is based on the excitation of the third radial vibration mode of the ring and the first bending mode of the trapezoidal-shaped cantilever. Motion control is performed by switching electric signals between the particular segments of the piezoelectric ring. A numerical investigation was performed to validate the operation principle of the robot and to analyze electrical and mechanical characteristics. Numerical investigations showed that the first bending mode of trapezoidal cantilevers and the third radial mode of the piezo ceramic ring were obtained at a frequency of 13.79 kHz and 95.75 kHz, respectively. Moreover, it was revealed that the coupling ratio between vibration amplitudes of passive and active segments is more than 4 times. The prototype of the piezoelectric robot was made and an experimental study was performed to validate the operating principle of the robot, as well as to investigate the dynamic characteristics. The investigation showed that the highest velocity of the planar motion is 22.3 mm/s while the maximum angular motion speed is 29.3 RPM when an excitation voltage of 200 Vp-p and payload of 25.1 g was applied.

Highlights

The design of the robot is based on a single piezoelectric ring and a triangular-shaped passive layer made from stainless steel
Numerical investigations showed that the first bending mode of trapezoidal cantilevers and the third radial mode of the piezo ceramic ring were obtained at a frequency of 13.79 kHz and 95.75 kHz, respectively
It was revealed that the coupling ratio between vibration amplitudes of passive and active segments is more than 4 times

Summary

Introduction

Modern optical instruments are widely used for industrial, measurement, laser, and manufacturing systems. Planar locomotion of the robot is obtained when a harmonic signal with a frequency of the first bending mode of the trapezoidal cantilever is applied to segment L0deg, L120deg or L240deg. Contraction and extraction of the ring segment excite the first bending mode of trapezoidal cantilever, and the semispherical contact impacts the manipulation surface and in this way generates planar locomotion of robot. The rotational motion of the payload around the X or Y axis is obtained in a similar way, i.e., by applying a harmonic signal with a frequency of the third radial mode of the piezoceramic ring to segment R0deg, R120deg, or R240deg. The step of the numerical investigation was performed to analyze the displacement amplitudes of the contact points and coupling ratio between vibrations of different segments of the robot when L and R segments of the piezo ceramic ring were excited. The goal of the investigation was to validate the operation of tricthseigronbaol.t aOnnd mtheeasoutrheetrhehaelnedct,ritchael avnadludyensaomf itchcehacroauctperliisntgicsr.atio show that vibrations cou pling have a minor influence on the accuracy and direction of angular and planar motion and can be controlled

Experimental Investigation of the Robot

Findings

Conclusions