Design and Gait Analysis of a Two-Legged Miniature Robot With Piezoelectric-Driven Four-Bar Linkage

This paper presents the design and development of a new type of piezoelectric-driven robot, which consists of a piezoelectric unimorph actuator integrated as part of the structure of a four-bar linkage to generate locomotion. The unimorph actuator replaces the input link of the four-bar linkage and motion is generated at the coupler link due to the actuator deflection. A dimensional synthesis approach is proposed for the design of four-bar linkage that amplifies the small displacement of the piezoelectric actuator at the coupler link. The robot consists of two such piezo-driven four-bar linkages and its gait cycle is described. The robot speed is derived through kinematic modelling and experimentally verified using a fabricated prototype. This result will be important for developing a motion planning control strategy for the robot locomotion, which will be part of future work.