Bionic legged robots have been developed to increase robots’ adaptation to different environments. The main advantage of legged robots is their ability to access places that are beyond the reach of wheeled robots. The level of performance demonstrated by biological systems has yet to be fully realized in a legged robot. Since driving actuators are mounted on the leg joints of the legged robots, the speed of these robots are low. Generally, two methods contribute to the high speed of quadruped - to change the leg morphology, by decreasing the inertia of the distal leg and introducing compliance. Another feasible way is the utility of high-power actuators. However, motors of these robots require clockwise and anticlockwise rotation periodically when the leg swings back and forth, which reduces the working efficiency of the motors. By using high torque density electric motors with backdriveable single-stage planetary gear reductions, and low-inertia legs, the Quadruped robot will be able to control ground

reaction forces through proprioception, without the use of any force sensors, torque sensors, or series compliance at the joints or feet.