Passive Steering of Miniature Walking Robot Using the Non-Uniformity of Robot Structure

This paper discusses the steering of a miniature, vibratory walking robot taking advantage of the robot's structural non-uniformity. Non-uniformity from fabrication and assembly can be detrimental to performance of miniature robots, but its potential for modifying robot locomotion is discussed in this work. A 3-centimeter-wide piezoelectric robot is described for the study of steering opportunities. This includes turning behavior that occurs away from resonance due to leg asymmetries and shuffling behavior caused by lateral motion of the actuators. Finite Element Analysis and beam theory are used to explain the resonances of the designed structure. The parameter variances are studied and experimentally validated, to illustrate the variability of locomotion effects emerging across the robot legs. Further explanation of the robot dynamics helps to determine possible mechanisms for steering, with rotational turning motion around resonance explainable with a previous dynamic model, and some candidate explanations for shuffling examined. The motion of the robot is recorded within the frequency range of 1.2 to 4.6 kHz, within which both turning and shuffling are observed in addition to longitudinal motion.