Robot design for bidirectional locomotion induced by vibration excitation

In this paper we design a robot that can move forward and backward based on the vibration excitation. The proposed design enables the robot to locomote on the horizontal surface using the vibration excitation that is perpendicular to the locomotion direction. The bidirectional locomotion is achieved, and the direction of motion is determined by the vibration frequency. This new type of robot is useful for the unconventional environment where complex moving mechanisms cannot be applied to the robots such as medical, small pipeline, and underwater vehicle applications. To this end, two springs with different stiffness are perpendicularly connected and support the main body of the robot. The dynamic response of this nonlinear system to the vibration enables the robot to walk forward and backward depending on the vibration frequency. The numerical simulation of this system and the experiments with actual hardware design verify the proposed approach.