Gait planning and transitions of walking robots on smooth and rough terrains

Legged locomotion presents great advantages over wheeled and tracked locomotion on unpaved, natural surfaces. The development of a practical legged vehicle requires a gait planning strategy that enables the legged system to change gait and/or walking direction while it is walking on a terrain with changing surface conditions. This thesis is to study gait planning for a quadruped and a hexapod based on the wave gait, the modified wave gait and the forward continuous follow-the-leader (FTL) gait.; For the gait planning for a quadruped, a gait planning for quadruped to change its walking direction is developed. The quadruped can either walk in a constant speed or adjust its speed before and after the turn. Such a gait planning includes four gait transitions: gait transition for the increase of the duty factor, from straight-line walking to turning, from turning to straight-line walking and for the recovery to the original duty factor. In the gait transition for the adjustment of the duty factor, the modified wave gait is applied so that the number of transition cycles can be reduced. Positive stability is maintained during the entire locomotion.; For the gait planning for a hexapod, the FTL gait is applied for walking on mildly rough terrain. Both the backward and forward continuous FTL gaits are studied. An approach of adjusting the front feet to avoid forbidden areas is developed. In order to prepare for turning, gait transitions between two forward FTL gaits are studied. Three strategies of gait transition with two, one and zero transition cycles are formulated. The turning of a hexapod using the forward continuous FTL gait is illustrated in an example.