Mechanism design and analysis of a novel 2-DOF compliant modular microgripper

Microgrippers play a crucial role in micro-/nanomanipulation systems dedicated to automatic handling of tiny objects. In this paper, an idea of modular design is proposed to devise a compliant microgripper with two degree-of-freedom (2-DOF) along with parallel translational motion of the gripper arms. A microgripper with 2, 3, and 4 arms is proposed as an illustration. The modular design enables easy adjustment of the initial clearance between the gripper arms and reduces the hardware cost in terms of manufacturing and maintenance. Based on the methodology of pseudo-rigid-body (PRB) model, analytical models are derived to quantify the gripper's stroke, actuation stiffness, and output compliance. The established models are verified by performing finite element model (FEM) simulations. The results confirm that the gripper has a decoupled translational motion in two axes and owns a high resonant frequency, which enables the adoption of simple control scheme as well as the generation of rapid transient response. The concept design presented in this paper provides a sound base in developing new microgrippers for micro/nano manipulation and assembly applications.