Control Law for Rough Terrain Robot with Leg-type Crawler

The purpose of this study is to develop a new mobile system using "leg-type crawler" mechanism. Our proposed "leg-type crawler" mechanism is a combination of crawler mechanism and walking mechanism. It has two links with crawler tracks and two rotational joints. The leg-type crawler is a unit which includes mechanisms and controller. The number of motors in leg-type crawler unit is 4. And this system has 4 leg-type crawler units. Thus the total number of motors is 16 in this system. Since this mobile system has high redundancy, it can take several moving modes. By combining such moving modes, it can move in almost all kinds of rough environments. To let the robot follow specified trajectory, we adopt a force distribution law to this system. The force distribution law is to allot the necessary force for main body movement to each leg-type crawler unit. In addition, we have to take into account the limitation of output forces of each unit. In this paper, we propose a control law with force saturation after showing the outline of the robot. We also verify this law by several experiments and simulations