Improving the energy efficiency and speed of walking robots

This study analyses the superior performance of gravitationally decoupled actuation in terms of energy efficiency, and hence autonomy. Based on the decoupling concept, a new design is presented for a 3 dof leg, and its performance is validated by including it in a 84 kg hybrid locomotion robot. The proposed leg obtains a straight-line constant-velocity motion of the foot as only one of its 3 motors is operated at constant speed. This feature, together with the hybrid structure, increases the robot’s efficiency and speed when operating on surfaces without obstacles, and drastically simplifies the walking operation control. A series of simulations have been done comparing the energy consumption of the hybrid robot including traditional coupled legs, and including the proposed decoupled legs. They show a superior performance of the later one. A real prototype has been built including the proposed mechanism. It shows a similar performance to that obtained from simulation, and a natural gait in flat terrains,at speeds up to 0.9 m/s.