Development of a micro-gripper using piezoelectric bimorphs.

Amr M El-Sayed,Noor Azuan Abu Osman,Nur Azah Hamzaid,Ahmed Abo-Ismail,Moumen T El-Melegy

doi:10.3390/s130505826

Amr M El-Sayed, Noor Azuan Abu Osman + Show 3 more

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https://doi.org/10.3390/s130505826

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Abstract

Piezoelectric bimorphs have been used as a micro-gripper in many applications, but the system might be complex and the response performance might not have been fully characterized. In this study the dynamic characteristics of bending piezoelectric bimorphs actuators were theoretically and experimentally investigated for micro-gripping applications in terms of deflection along the length, transient response, and frequency response with varying driving voltages and driving signals. In addition, the implementation of a parallel micro-gripper using bending piezoelectric bimorphs was presented. Both fingers were actuated separately to perform mini object handling. The bending piezoelectric bimorphs were fixed as cantilevers and individually driven using a high voltage amplifier and the bimorph deflection was measured using a non contact proximity sensor attached at the tip of one finger. The micro-gripper could perform precise micro-manipulation tasks and could handle objects down to 50 μm in size. This eliminates the need for external actuator extension of the microgripper as the grasping action was achieved directly with the piezoelectric bimorph, thus minimizing the weight and the complexity of the micro-gripper.

Highlights

Piezoelectric materials are ideal for systems such as micro-grippers due to their fast reaction time and miniaturization potential [1]
The first setup was for measurement of static and dynamic characteristics of the piezoelectric bimorph (Figure 4) while the second setup is the general layout of the developed micro-gripper based on the previously obtained characteristics (Figure 5)
The characteristics of the developed micro-gripper in terms of all possible responses of the piezoelectric bimorphs were presented by measuring the bimorph's deflection

Summary

Introduction

Piezoelectric materials are ideal for systems such as micro-grippers due to their fast reaction time and miniaturization potential [1]. They have been used as sensor and actuator components due to their unique reversible electrical and mechanical properties. On the other hand, bending actuators consist of multilayers of piezoceramics with greater length than the stacked type. Those multilayers can either be double mounted or single ended as a cantilever [5]. A special case of multilayer bending actuators is the piezoelectric bimorph actuator, which consists of two layers of piezoelectric material connected over their length surfaces. Piezoelectric bimorphs have been involved in areas related to precision position control, loudspeakers, vibration damping, noise control, relays, phonograph pick-up, acoustics, and pressure sensing [9]

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