Abstract
In this research a one-legged robot which can achieve hopping motion is analyzed and implemented. The robot has two rotational joints respectively located at the ankle and the knee. Each of the joints is equipped with a rotary actuator and a torsional spring that emulate the actuation and the passive stiffness in human muscles. Particularly, the actuators used are called series elastic actuators which can provide back-drivability for exploiting the natural dynamics of the robot. By exciting the resonance in the mechanical dynamics, the input energy can be accumulated and the robot can hop with less demanding actuation torques. The hopping performance of the robot is verified by simulations and experiments. Experimentally, the robot can perform continuous and stable hopping with the maximum height of about 8mm.