Design, analysis, and experimental investigation of a single-stage and low parasitic motion piezoelectric actuated microgripper

The demand for high precision micro/nano manipulation is increasing for advanced manufacturing technology. The precise motion of the microgripper jaw is required to achieve high performance micromanipulation tasks. The parasitic motion of the microgripper reduces placement accuracy during pick and place tasks. This paper presents an asymmetric design of piezoelectric actuated microgripper. It investigates key characteristics including parasitic motion, output displacement, and displacement amplification ratio. The microgripper is designed with a single-stage displacement amplification mechanism to form a compact layout. The design of the microgripper integrates the bridge-type mechanism and the parallelogram mechanisms. The bridge-type mechanism amplifies the piezoelectric actuator output and the parallelogram mechanisms offer linear motion of the gripper jaw. The analytical modeling and finite element analysis were conducted to evaluate the characteristics of the microgripper. The design parameters of the microgripper were optimized through several finite element analysis. Further, experimental studies were conducted to verify the characteristics of the microgripper. The parasitic motion of the jaw was obtained as less than 0.18% of the microgripper jaw motion in the x-direction. The mechanism of the microgripper also achieves a high positioning accuracy. Further, a high displacement amplification ratio and large output displacement can be achieved.