A composite algorithm for flow rate reduction and stable body trajectory generation in a hydraulic actuated quadruped robot with kinematic redundancy

A hydraulic actuator has a various merits. It has a small size and a high power-to-weight ratio. So it is able to generate high torque in small size actuator. These features of hydraulic actuator are very useful for a walking robot. However, the hydraulic actuator needs a hydraulic power-pack which supplies pressure and flow. Usually, a big and heavy power-pack is needed to generate high pressure and large flow rate. Especially this power-pack is a burden to the stand alone type robot. Therefore it is very important o minimize the size of the power-pack. In this paper, we propose a redundantly actuated quadruped robot which is driven by hydraulic actuator. Using the kinematic redundancy of each leg mechanism, a flow rate consumption minimization algorithm is proposed, which allows minimizing the size of a power-pack. We demonstrate the reduction of the flow rate of the robot through simulation and experiment.