Earthworm-Inspired Robot Design: Reducing the Number of Actuators Through Embedded Motor Between Segments

Abstract

Typically, earthworm-inspired robots consist of N segments and N actuators, each segment having one actuator. However, to reduce the number of actuators, complex mechanisms are often required to activate multiple segments. In this study, we introduce a novel design for an earthworm-inspired robot that reduces the number of actuators from N to N-1, thereby simplifying the mechanical complexity while maintaining high performance. Our proposed robot consists of three segments and two motors embedded between the segments. These two motors share a single flexible shaft and move back and forth along it. By extending or retracting the segments through the movement of the motors, the robot is propelled forward. We evaluated the robot’s performance, achieving a maximum speed of 11.6 mm/s, a payload capacity of 200 g (three times its own weight), and a climbing angle of 20 degrees, demonstrating its superior capabilities in various scenarios. The proposed robot generates significant force through simultaneous motor actuation and exhibits effective steering locomotion with additional actuators. This study introduces a new design approach for earthworm-inspired robots and offers valuable insights into achieving locomotion with fewer actuators.

Keywords

• Earthworm robots
• piezoelectric actuators
• soft robots
• ultrasonic motors