In the future, as the fields of activity for mobile robots extend, robots will have to coexist with humans in order to perform various tasks. The robots will be expected to adapt to usual human environments and move autonomously. Of course, it is possible to implement high-level functions on a single robot. However, it is not feasible from the viewpoints of cost, robot size, technical difficulties and so on. Hence, we will not require robots to have perfect faculties, but will instead have the environment (or the human) provide some of them (see Fig. 1). We develop the system for practical use.

• Environments provide faculties to robots - Environment design / Environment usage

We solve the following two problems and integrate into one system.

1. A study on problems of environment design: We put marks on objects in the environment. The robots measure them and achieve tasks. The marks are artificial objects designed to be measured by the robots and thus give them information about not only their own positions and orientations but also task processing instructions. We consider following two issues as important; where should marks be put in the environment to suit measurement by the robot? and how much information should a mark have for the task?
2. A study on problems of environment usage: The supply of energy is an important factor. It can be problematic for mobile robots to drag overlong electric cords. On the other side, the capacity of batteries is limited. Hence, robots need to use wall sockets and change sockets depending on their position in order to extend their range and operation time (see Fig. 2).

• The human provides faculties to robots

While dealing with multiple mobile robots, the system seldom has true autonomy. We research operation methods to complement the imperfect faculties of robots. When many robots are present, it is impossible for the user to command robots individually and catch up the situation of the whole system. We consider the appropriate relationship between the human and the robots, and develop a system as shown in Fig. 3.

Fig. 1 Human-robot coexistence

Fig. 2 Use of wall sockets Fig. 3 A human and multiple mobile robots