Uneven terrain negotiable mobile platform with passively adaptive double tracks and its application to rescue missions

This paper presents the design and integration of ROBHAZ-DT3, a newly developed mobile robot system with a chained double-track mechanism. It is designed to carry out military and civilian missions in various hazardous environments. A passive adaptation mechanism equipped between the front and rear body enables ROBHAZ-DT3 to have good adaptability to uneven terrains, including stairs. The passive adaptation mechanism reduces energy consumption when moving on uneven terrain. It has a simple design and remote control, since no actuators are equipped for adaptation. Based on this new design concept, dynamic analysis and simulations were conducted to verify the mobility of the double-track mechanism, and to obtain significant design parameters such as the optimal track size and allowable attack angle. Also, dynamic effects in vehicle turning were investigated to assess the proper driving torque. Based on this novel mobile mechanism, a rescue version of ROBHAZ-DT3 with appropriate sensors and a semi-autonomous mapping and localization algorithm was developed to participate in the RoboCup 2004 US Open (Urban Search and Rescue Competition). From the various experiments in the realistic arena, we verified that ROBHAZ-DT3 is reliable when traveling over rugged terrain, and that the proposed mapping and localization algorithm are effective in unstructured environments with uneven ground like the rescue area.