Development of a Miniature Piezoelectric Robot With High Stability and Strong Load Capacity Based on Hexapod of Radial Layout

In this work, a novel hexapod miniature piezoelectric robot (HMPR) was proposed. It utilized a circular arrangement and a triangular gait scheme to achieve high motion stability and strong load capacity. The working principle and exciting signal schemes were illustrated. The dynamic model of the piezo-leg was established to guide the determination of its parameters. The prototype piezo-legs were fabricated and their vibration shapes and bending displacements were tested, the results verified the feasibilities of the dynamic model and the working principle. Then, the prototype HMPR was fabricated with size of 63 x 72 x 13 mm(3) and weight of 21 g. It performed strong carrying capability of 800 g, more than 38 times its own weight, and the load-to-weight ratio was the largest compared with the reported MPRs. Notably, the HMPR exhibited high motion stability, including the high repeatability of step displacements, high displacement repeatability, low lateral coupling, and small posture change of large stroke motions. Moreover, the point-to-point positing control was tested, and the application in wafer detection was investigated; the results illustrated that the HMPR could achieve large travel range with micropositioning precision, and had much potential to be applied in precision device detection.