Non-reciprocating legged gait for robot with epicyclic-gear-based eccentric paddle mechanism

A novel eccentric paddle mechanism based on epicyclic gear mechanism (ePaddle-EGM) has been proposed to enhance the mobility of amphibious robots for multi-terrain tasks with diverse locomotion gaits. This paper proposes a unique non-reciprocating legged walking gait for a quadruped or hexapod robot based on ePaddle-EGMs after a brief kinematic analysis of the ePaddle-EGM. During the gait, the robot can generate desired periodic motion of the legs in the swinging and supporting phases while maintaining all the actuators rotating unidirectionally. Advantages of the proposed non-reciprocating legged gaits include that influence of backlash in the epicyclic gear mechanism could be eliminated and accuracy of locomotion can be guaranteed. Experiments on a single ePaddle-EGM prototype module were conducted to validate the proposed mechanism design and the idea of deploying the non-reciprocating legged walking gait to improve locomotion accuracy and energetic efficiency of the robot. A non-reciprocating legged gait is proposed for an ePaddle-EGM-based robot.Gait sequence and planning method for this gait are discussed and verified.Locomotion accuracy is secured with the gait in the presence of gear backlash.Robot walks more efficiently in this gait than in legged crawling gait.