Effect of swing legs on turning motion of a free-falling cat robot

Based on self-righting principle of a free-falling cat, a multi-rigid-body dynamic model of a cat robot is built with the consideration of swing legs and the relation between turning rate and swing angle of legs is got. Mechanical structure of the cat robot is designed and dynamics simulation is carried out to validate the theoretical analysis. Simulation results indicate that flip angle of the cat robot becomes larger with the increase of angle or angular velocity of swing legs. By contrast, the change of swing angle has more influence on flip angle of the cat robot. Adjusting angle and angular velocity of swing legs to suitable numerical values, energy consumption of turning motion can be reduced effectively.