Design and Experimental Evaluation of a Fast Torque-Controlled Hydraulic Humanoid Robot

This paper reports the design and control of a fast torque-controlled hydraulic humanoid robot, TaeMu. The robot has 15 active joints that are all driven by hydraulic servocylinders with an external hydraulic power supply. The 1377-mm tall robot has a three-axis active torso used for static and dynamic balancing. It weighs 72.3 kg including a dummy weight stand for the arms. Its lightweight design with carbon-fiber-reinforced plastic allows the legs to have a similar mass distribution to that of human legs. We present the details of the hardware design including the hydraulic actuator selection, mechanism, and control systems, as well as the passivity-based controller design for joint torque control and whole-body motion control. We present experimentally obtained results, such as speed testing, basic torque control testing, full-body compliant balancing with attitude regulation/tracking, and balanced full-squat motions. The experimentally obtained results and estimated joint specification imply the high potential of the robot to perform human-like motions if the researchers can invent proper control algorithms.