Terrain-Adaptive Gait for Walking Machines

One of the primary advantages of walking machines is their inherent capacity for moving over different terrains. However, it is important to provide algorithms that modify the gait ac cording to the terrain. Existing articles about terrain-adaptive locomotion are based on intelligent foothold selection, and use periodic and/or aperiodic gaits. This article proposes a strategy to adapt walking robot locomotion to an irregular terrain in real time that is based on the variations of parameters of a periodic gait affecting leg coordination. Its main feature is that it does not require knowledge of footholds. In addition, this adaptive gait control can be incorporated into a system with external stereoceptive sensors to select footholds. As a working example, a particular class of periodic gaits, called wave-crab gaits, are used in a quadruped robot. However, the proposed adaptive-gait method can be used for any other periodic gait and for robots with a greater number of legs. Adaptive-gait control has been implemented in a quadruped robot named RIMHO, demonstrating its ability to move over different ter rains. Static stability results from computer simulations and experimentally obtained velocity results are also presented.