Single-rod brachiation robot: Mechatronic control design and validation of pre-jump phases. (submitted draft)

Abstract

A complete mechatronic design of a minimal configuration brachiation robot is presented. The robot consists of a rigid single-rod with gripper mechanisms attached to bothp ends. The grippers are used to hang the robot arm on a horizontal bar on which it either swings or rotates. The motion is imposed by repositioning the arm robot’s center of mass, which is performed by a crank-slide mechanism. Based on a non-linear model, an optimal control strategy is proposed for repositioning the center of mass in a bang-bang manner. Consequently, utilizing the concept of inputoutput linearization, a continuous control strategy is proposed which takes into account the limited torque of the crank-slide mechanism and its geometry, is proposed. An enhanced attention is paid to energy accumulation towards the subsequent jump-stage of the brachiation.These two strategies are first validated and compared in simulations. The continuous control strategy is then also implemented within a low-cost Arduino based control system of the robotic arm and the swing stage of brachiation motion is validated experimentally.