Suppression of Energy Consumption for Snake Robots using Parallel Elastic Actuators during Low Speed Movement

Abstract

This paper investigates a method to suppress the energy consumption of snake robots using parallel elastic actuators (PEA) during the low speed movement. It has been widely known that the PEA-based robot can greatly reduce the torque if its movement synchronizes with the resonance frequency. However, the PEA installation actually degrades the energy efficiency when the speed changes are dramatic since the PEA disturbs the movement. Therefore, even if the spring was designed so as to increase the efficiency during high speed movement, the spring prevented the movement during low speed movement. To solve this problem, we propose changing the initial winding angle of the serpenoid curve to suppress the energy consumption of the snake robot without changing the spring. To verify how the different initial winding angle changes the energy consumption without changing the springs, simulation and experiment were examined. From the results, although the losses incurred by friction in the gear chain and heating of the circuits inside the servo motors are not small, the different initial winding angle decreased the robot’s energy consumption.