Bio-Inspired Controller for a Robot Cheetah with a Neural Mechanism Controlling Leg Muscles

The realization of a high-speed running robot is one of the most challenging problems in developing legged robots. The excellent performance of cheetahs provides inspiration for the control and mechanical design of such robots. This paper presents a three-dimensional model of a cheetah that predicts the locomotory behaviors of a running cheetah. Applying biological knowledge of the neural mechanism, we control the muscle flexion and extension during the stance phase, and control the positions of the joints in the flight phase via a PD controller to minimize complexity. The proposed control strategy is shown to achieve similar locomotion of a real cheetah. The simulation realizes good biological properties, such as the leg retraction, ground reaction force, and spring-like leg behavior. The stable bounding results show the promise of the controller in high-speed locomotion. The model can reach 2.7 m·s ^-1 as the highest speed, and can accelerate from 0 to 1.5 m·s ^-1 in one stride cycle. A mechanical structure based on this simulation is designed to demonstrate the control approach, and the most recently developed hindlimb controlled by the proposed controller is presented in swinging-leg experiments and jump-force experiments.