DESIGN OF A HYDRAULICALLY ACTUATED ARM FOR A QUADRUPED ROBOT

A common disadvantage of quadruped robots is that they are often limited to load carrying or observation tasks, due to their lack of manipulation capability. To remove this limitation, arms can be added to the body of the robot, enabling manipulation and providing assistance to the robot during body stabilization. However, a suitable arm for a quadruped platform requires specific features which might not all be available in off-the-shelf manipulators (e.g. speed, torque-controlled, light-weight, compact, without external control unit). In this paper, we present a systematic approach to design a robotic arm tailored for an 80kg quadruped robot. A full robot with arms and legs (aiming for a centaur- style robot) was simulated performing a range of "representative" tasks to estimate joint torques and velocities. This data was then extensively used to select the design parameters, such as the joint actuators to develop a novel, compact (0.743m fully extended), light-weight (12.5kg), and fast (maximum 4m/s no-load speed at end-effector) hydraulically actuated robotic arm with 6 torque-controlled degrees of freedom. The enclosed video presents preliminary experimental results.