Contents I. Introduction
Recently, the work/rescue robots are required to work flexibly from keep out, natural disasters, and nuclear reactor. Conventionally, a multifunctional and high performance rescue robot has been advanced[1], [2], because setting many rescue robots is difficult in limited space and cost. However the multifunctional and high performance work/rescue robot alone is not useful, the conventional robots are difficult to support the unexpected situation. Then, a modular robot will be effective because it can work in the various situations. A modular robot consists of many modules. A module consists of the same shape, function, easy structure, and standard. It has simple move function, but the robot of combined many modules is the various functions. And the function is maintained by exchange a broken module for a new module in failure. A modular robot of the walking, snake, circle type has been proposed in conventional research[3], [4], [5]. It has various functions by combining many modules. For example, if human or robot can't enter the place, the modular robot can enter it by changing the shape. And the modular robot can maintain the function by exchanging disabled module to the other module. Therefore, the modular robot is effective in disasters. Then, many modules must be produced on a large scale. In order to mass-produce modules, the manufacturing method of simple processes and high speed/reproducibility is required. If the structure is complicated, mass production is difficult by much production time.
