Design, computational analysis and experimental study of a high amplification piezoelectric actuated microgripper

Increasing applications of compliant microgripper demands flexibility in working with a wide range of micro-objects which requires a large workspace, high precision motion, low parasitic motion, and satisfactory bandwidth control. To meet the requirement of pick and place manipulation tasks, a high amplification piezoelectric actuated microgripper is proposed and investigated in this paper. The high amplification of the microgripper is achieved using a compound amplifier. The compound amplifier is assisted to magnify the embedded piezoelectric actuator's displacement. Two cascaded lever-type mechanisms are symmetrically connected with a bridge-type mechanism and form a three-stage amplification mechanism-based compound amplifier. Further, the four-bar parallelogram mechanisms are integrated with the third-stage displacement amplification mechanisms to linearize the output motion of the microgripper jaws. The characteristics of the microgripper were evaluated by computational analysis and validated using experimental investigations. Further, the design parameters are identified from the geometrical model of the individual displacement transmission mechanisms to perform a response surface optimization on the configured mechanism by the computational method. The design optimization of the microgripper resulted in a high displacement amplification ratio with a large workspace. The experimental investigations show that the designed microgripper is capable of achieving a high displacement amplification ratio of 34.5 and a total output displacement of 529.4 mu m. Further, the characteristics of the microgripper such as motion resolution, and parasitic motion indicate that it will be able to perform high-precision micro-object grasping/releasing tasks.