Development of a Micro-Gripper Using Piezoelectric Bimorphs

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.

Innovative Silicon Microgrippers for Biomedical Applications: Design, Mechanical Simulation and Evaluation of Protein Fouling

“…Among others, an untethered mobile microgripper controlled by an external electromagnetic coil system has been reported [4], where the manipulation of different microgels was successfully demonstrated with a pick-and-place robotic heterogeneous 3D assembly technique. A few more examples of microgrippers are present in the literature, piezoelectric [5,6] or thermally [7,8] or even magnetically actuated [8][9][10]. All these systems, however, present quite large dimensions and are not fully tested for working in a physiological environment, as required for biomedical applications.…”

Non-Linear Piezoelectric Actuator with a Preloaded Cantilever Beam

“…The moonie, cymbal, and drum piezoelectric actuators can obtain large displacements, but they require a high driving voltage. Bimorph piezoelectric cantilevers have greater applicability because of their greater displacement ability and simple structure [11,[14][15][16]. However, their output forces are inversely proportional to the output displacement, and further improvement of the displacement has been limited.…”

State of the Art Robotic Grippers and Applications

“…Piezoelectric bimorphs have also been analyzed theoretically and experimentally in [120]. The study focused on the transient response and the frequency response with various input voltages and signals along the length of the actuator.…”