Robot Brachiation With Energy Control

Abstract

Branching structures are ubiquitous elements in several environments on Earth, from trees found in nature to man-made trusses and power lines. Being able to navigate such environments provides a difficult challenge to robots ill-equipped to handle the task. In nature, locomotion through such an environment is solved by apes through a process called brachiation, where movement is performed by hand-over-hand swinging. This thesis outlines the development of a two-link Brachiating robot. We will present our work on implementing an Energy-based Controller where we inject or remove energy into the system before assuming the grasping posture. We will show that the controller can solve the ladder problem and swing-up for continuous contact brachiating gaits, and compare it to other control approaches in simulation. We will also show our work in developing a real-world brachiating robot, and show the implementation of our controller in this robot. The robot developed in this thesis moves only on a 2-D plane, and traverses by swinging on one inch thick aluminum tubes spaced 50-65cm apart. These tubes are positioned perpendicular to the 2-D plane the robot moves on. The two-link structure and simplified 2-D motions allows us to better study the control algorithms needed for brachiating locomotion.