A Bio-Inspired Quadruped Robot with Foldable Torso Capable of Omnidirectional Motion

Many quadrupeds have a flexible torso and can achieve pivot steering, which makes them have good flexibility and mobility. But the torso is usually simplified to a rigid body for most quadruped robots. This paper proposes a novel bioinspired quadruped robot with foldable torso that is capable of omnidirectional motion. First of all, a flodable torso with a fully symmetrical mechanism is designed to realize variable configurations of the torso. The obstacle surmounting ability of the quadruped robot can be improved by changing the distance between legs and the height of the torso from the ground. Then, a parallel actuated leg capable of omnidirectional swing is designed, enabling the quadruped robot to realize omnidirectional motion including in-situ turning and backward walking. The foldable torso and omnidirectional mobility allow the quadruped robot to be more adaptable to complex environment. Effectiveness of the proposed quadruped robot is verified by simulations and experiments on the prototype.