Setting Objective Parameters of a Hopping Robot Based on Power Consumption

A procedure for setting the objective parameters (forward velocity, step length, jumping height, angular momentum, landing and take-off configuration) for a mechanical prototype of a hopping robot with an articulated leg is presented. The goal is to obtain an energy efficient locomotion on irregular terrain, using torque and power limited electric actuators, as well as tuned passive actuation. The prototype weighs 11.7 kg and consists of an upper body, an upper leg and a lower leg. The algorithm being used, is based on a close examination of the machine’s passive dynamic behaviour throughout a specific range of investigated locomotion patterns. By an adjustment of the passive motion, the desired objective parameters are attained using as minimum actuation as possible. This approach enables the control of the robot’s motion, while adjusting the step length up to 0.5 m and the forward velocity up to 0.9 m/s, whereas the driving torques and the power supply are limited to ±40 Nm and 400 W respectively. The maximum driving torques and the maximum power consumption is well within the range of the specifications of the prototype’s built in actuators.