Abstract: The ground -to-wall transition programming of a multi-legged robot with actual constraints is more complicated than that with ideal constraints. After discussing the specific characteristics of actual constraints for a newly-developed leg -pad mechanism with three degrees of freedom, the so-called "virtual pad removal" and "virtual surface" concepts are proposed in order to simplify transition gait programming, and the goal function and influencing factors are discussed. By means of computer simulation of an actual example, the feasibility of transition motion strategy of alternating tripod gait with the robot's body centerpoint moving along elliptic trajectory is verified.

Key words: ground-wall transition, legged robot, gait programming, actual constraints