System dynamics simulation and prototype design of a high efficient legged robot based on hybrid-driven mechanism

A novel legged robot based on hybrid-driven mechanism is proposed in this paper. With the hybrid-driven mechanism as its legs, the robot was designed to achieve high energy utilization efficiency for the unidirectional motion of the main actuators, and flexibility for the motion of the servo actuators. The hybrid-driven mechanism was analyzed with the goal to obtain a suitable foot trajectory, and a seven-bar linkage mechanism with a rotary actuation and a linear actuation was designed. Based on this seven-bar mechanism, the simulation model of the robot was built. The simulations of the system dynamics simulations show that the robot could have a good gallop gait running in a straight line without the motion of servo actuators, and could turn the orientation flexibly by moving the servo actuators. Based on the above analysis, a prototype of hybrid-driven legged robot (HDLR-I) was built; the experiments of the single-leg shows that the leg could run at high speed with a low output torque for the main motor.