A Monolithic Compliant Piezoelectric-Driven Microgripper: Design, Modeling, and Testing

TLDR

The paper presents a piezoelectric‑driven microgripper that integrates a monolithic compliant mechanism with built‑in gripping‑force and tip‑displacement sensors. The microgripper uses a stack piezoelectric ceramic actuator coupled to a monolithic compliant transmission, with a pseudorigid‑body model linking input force and displacement to output force and displacement and achieving a 16× displacement magnification. Experiments confirm the model’s accuracy, demonstrate precise force and displacement sensing, and show that the device achieves a 16× magnification while maintaining parallel jaw motion and constant magnification.

Abstract

In this paper, we report on the design, modeling, and experimental testing of a piezoelectric-driven microgripper making use of both an integrated gripping force sensor and an integrated tip displacement sensor. In the developed microgripper, a stack piezoelectric ceramic actuator is used to simultaneously obtain the tip displacement and the gripping force. A novel monolithic compliant mechanism is proposed to act as the microdisplacement transmission mechanism to obtain the large tip displacement and to provide the possibility of integrating both the gripping force sensor and the tip displacement sensor into the microgripper. The relationship between the gripping force, tip displacement, input force, and input displacement of the piezoelectric-driven microgripper and the dynamic model are established using the pseudorigid-body-model method. The characteristics of the developed microgripper are tested and the case of gripping an optical fiber is presented. The experimental results indicate that: 1) the theoretical model for the developed microgripper matched well with the measured results; 2) the integrated gripping force sensor and tip displacement sensor could accurately measure the gripping force and tip displacement; 3) the developed microgripper could achieve a displacement magnification of 16.0 × with respect to the stack piezoelectric ceramic actuator to realize the large tip displacement with high resolution but is also able to possess the parallel movement of its gripping jaws and the constant displacement magnification.