Fluid Powered Soft Cord Robot aiming to move in the sand

Abstract

In this study, we aim to develop a soft robot which can propel in sand smoothly by travelling wave locomotion. To move inside the sand, sufficient amplitude wave needs to be generated by the propulsion mechanism. In this paper, we propose a new pneumatic bending actuator which has large power and displacement of travelling wave. By connecting these actuators in series, a soft cord type robot with undulate propulsion mechanism can be realized. Through propulsion experiment, we stumbled on that at low pressure the robot can only move in the same direction as wave travelling direction, while at high pressure the robot move in opposite direction. To encounter this problem, we introduce two different propulsion principle, named propulsion by propagation of strain in low pressure and propulsion by counter force in high pressure. By utilizing this two propulsion principle and design the middle part in thicker structure, we can improve the travel length and propulsion velocity of the robot