A complete mechatronic design of a minimal configuration brachiation robot is presented. The robot consist of a rigid bar with gripper mechanisms attached to both ends. The grippers are used to hang the robot arm on a rod on which it either swings or rotates. The motion is imposed by repositioning the gravity centre of the arm, which is performed by a crank-slide mechanism. Based on the simplified non-linear model, an optimal control strategy is proposed for repositioning the gravity center in a bang-bang manner. Consequently, utilizing the concept of input-output linearization, continuous control strategy is proposed which takes into account the limited torque of the crank-slide mechanism and its geometry. These two strategies are first validated and compared by simulations. An enhanced attention is paid to energy accumulation towards the subsequent jump-stage of the brachiation. The continuous control strategy is then implemented within a low-cost Arduino-based control system of the robotic arm and the swing stage of brachiation motion is validated experimentally.
The experiments have been performed at laboratories of Professor Ikuo Mizuuchi, Department of Mechanical Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan.
