High performance integrated electro-hydraulic actuator for robotics - Part I: Principle, prototype design and first experiments

We design a new high performance integrated electro-hydraulic actuator (IEHA). We propose a new solution to a still open question in robotics, to provide an efficient and compliant actuation. The proposed actuator, which is dedicated to motorize independently each joint of a robotic system is designed to be fixed as near as possible to the joint itself, enhancing the performances while reducing the usual drawbacks of classical hydraulic actuation. The novel IEHA contains an integrated micro-pump with a floating barrel allowing the inversion of the flow direction without inverting the rotation of the input electric motor. The integration of a micro-valve and a rotary hydraulic distributor ensure the compactness of the proposed solution. In this paper, first, the proposed hydraulic actuation principle is given in detail. Then the designed prototype and the first experiments are presented demonstrating the novelty and the efficiency of our solution.