Local obstacle recognition for a quadruped robot by distance sensors

Legged walking robots are able to not only move on irregular terrain but also change its posture. For example, the robots can pass under above head obstacles with crouching. These advantages are particularly effective in three dimensional complex environment which wheeled robots cannot move on. However, some of the issues of a walking robot include instability and workspace limitation. All of these impact on the realization of applications. We have studied for the improvement of them and deadlock-less gait pattern, called trajectory following gait (TFG), has been proposed. Here, the advantages of walking robots are remarked again. In order to get the most out of these advantages, an environment recognition is absolutely imperative. Applying the vision sensor to the walking robot, however, is difficult because misconception can be occurred easily by the rocking vibration. Although rough surrounding information for global planning should be recognized by the visual sensor, more reliable sensing is desirable by the local one, i.e. steps and above head obstacles. This paper presents the reliable sensing method for a local obstacle recognition using distance sensors. The overcoming locomotion and a posture control method are also proposed. Finally, the local recognition availability is verified by some experiments.