The autonomous vehicles have been needed increasingly in the wide field of scouting in hostile environment, assessing situational danger, detecting mines, investigating sites contaminated by radiation, biological agents, etc. In the point of the driving capability, tracked locomotion has the best performance among several locomotion systems. However it has a weakpoint on energy consumption. For this reason, variable configuration tracked vehicles (VCTV) have been developed.
In this paper, a new mechanism is developed to reduce a turning energy and climb stairs. This mechanism has four tracks. Each track rolls around three wheels. When changing the driving direction, each module of the track and wheels rotates to minimize the contact area with ground. This mechanism has the better performance than other VCTV in energy consumption of turning, because it comes in line contact with the ground as wheeled vehicles. Furthermore this mechanism is more stable than other VCTV on the rough terrain, because four wheels support this mechanism. When climbing stairs, each module rotates to obtain a front attack angle and keep stability on steep stairs. This mechanism can climb stairs using the smaller transformation energy than other VCTV because this mechanism can obtain adaptable stair-climbing form by transformation.
The design parameters of components of modules are optimized to enhance the performance of climbing stairs. The performance indices related to climbing stairs are a stable angle, a climbing ability, a height of the vertical obstacle. As a result, in case that the overall size of the mechanism is 0.2m, it is obtained that the radius of the wheels should be 5mm and the length of the partition of the track contacted with the ground should be 0.09m to climb higher and more inclined stairs.
