Cooperative Transportation by Mobile Robots Coping with Environment

Our main research interest is to design cooperative strategy among mobile robots dealing with a common object. It is required for cooperative transport system by multiple mobile robots to achieve their task surely and efficiently. That is, robot motion should be planned to cope with difficulties, such as obstacles in their way, based on the information they sensed. Each robot is, however, limited in sensing area and in amount of information it can deal with. Therefore, it is difficult to know adequately about environment based only on individual information. From the observation of human task in object transportation, we have got some ideas of cooperative strategy as follows: (1) Humans assign several tasks dynamically among them. There are not only humans actually transporting an object, but also those clearing obstacles in their way, those opening the door, etc. (Fig.1). (2) They regrasp (change their positions to sustain) an object if their bodies prevent transportation from going on especially in narrow space (Fig.2). (3) They acquire environmental information efficiently by changing an object of their attention according to the situation. For example, they watch around to search for approaching obstacles when they are in relatively wide space, and they watch carefully at the edges of an object so that the object will not collide into the wall. Direction of watching is also different from each other (Fig.3).

Getting ideas from this observation, we are now working on motion planning method associated with gdynamic task assignmenth considering gcooperative sensing strategyh according to the environment. gDirection of attention (view)h and gposition to workh are planned.

Keywords: Multiple Mobile Robots, Cooperative Transportation, Task-assignment, Regrasping


  1. Natsuki MIYATA, et al.: Cooperative Transport with Regrasping of Torque-Limited Mobile Robots, In Proc. the 1996 IEEE Int. Conf. on Intel. Robots and Systems, Osaka, Japan, November 1996.
  2. Natsuki MIYATA.: Cooperative Transport System with Regrasping Car-like Mobile Robots, In Proc. the 1997 IEEE Int. Conf. on Intel. Robots and Systems, Grenoble, France, September 1997., et al


Fig.1 Dynamic Task Assignment Fig.2 Change of Attention and Sustaining Position Fig.3 What to plan?