Experimental Evaluation of Piezoelectric Self-Sensing during Terrestrial Locomotion of a Miniature Legged Robot

Abstract

This paper discusses the relationship between observed locomotion of a miniature terrestrial robot and measurements from a passive on-board piezoelectric sensor. The 30 mm-wide piezoelectric robot prototype is assembled for legged locomotion under various frequencies and voltages. Onboard sensing is realized using unactuated piezoelectric elements from among the robot's legs. The relationship between the sensing signal and vertical robot foot motion is interpreted through theoretical analysis and validated with experimental measurements. Whether the sensing signal can infer longitudinal robot locomotion is discussed with some empirical evidence, observed under various actuation conditions. Furthermore, environmental influences such as ground slope and surface properties and how on-board sensing reflects these changes are investigated. Some correlation is observed between longitudinal robot speed and simple features such as sensor amplitude.