A loss of lives caused by accidents and nature disasters such as collapse, fire, and earthquake is increasing day by day. So, many countries have organized the systematic rescue-teams and developed the ultramodern rescue-equipments to reduce and minimize the extent of damages. For example, eight rescue robots have saved more than ten people at collapsed World Trade Center in USA (911 terrors). Like this, the concern about rescue-activities and rescue-robots has spread to the mass of people. This paper introduces a new type of driving mechanism for rescue robot that has a variable geometry single-track which satisfies the pre-conditions for rescue robot. This mechanism is a symmetric configuration that has dual directions and prepares against overturn. By using transformation, it can reduce the energy consumption in steering and rotating. And also it maximizes the ability to overcome obstacles, like steps. It is designed to make the size of robot compact and to have the low center of gravity in driving on steps. Also, we optimized the design variables of components determining the shape of reverse-trapezoid frame to enhance the adaptability to 6 phases of climbing steps. After manufacturing this system, we have confirmed the strong possibility of realization of presented driving mechanism for rescue robot from various experiments.
