Position-based motion control and adaptability of periodic gaits for realistic walking machines

The paper deals with both mechanical problems that appear in realistic legged vehicles and algorithms to modify the gait according to the terrain. Flexion in links and joints produces a change in both the attitude and the position of the body which must be corrected for realistic walking. Because this phenomenon is difficult to model; the paper presents an attitude/position control strategy based on position control. This algorithm also allows the robot to be kept level while moving over irregular terrain. Furthermore, this paper proposes a strategy to. adapt a periodic gait to an irregular terrain in real time, which is based on the variation of parameters affecting leg co-ordination. This algorithm does not require prior knowledge of footholds. However, this adaptive gait control can be incorporated into a system with external stereoceptive sensors to select footholds. Both control strategies are aimed at a class of periodic gaits known as wave gaits. The aforementioned motion control algorithms have been tested successfully in the RIMHO walking robot.