Structural analyses were performed for a movable seat mechanism applied in a new type shower commode wheel chair. The wheel chair has slide rails below the wheel chair seat to help patient move to bed side. The slide rails and seat were modeled for the structural simulation. Experiments were performed to validate simulation results by using strain gage Rosettes. Student t-test was performed to the experimental data, which showed that the stresses obtained from the simulation were not significantly different from those obtained from the experiments. The slide rail structure was found to give a safety factor of 2.4 under 80Kg user weight with ten rollers used for seat support. The safety factor much increased by placing more rollers under the wheel chair seat. Our simulation revealed that rollers installed only in the central and corner regions were used as supports due to the bending deformation of the seat.

When problems occurred in the unstable and/or extreme terrain environment, formal field-driving robots were unable to provide any other options such as the transformation of the wheel and body structure, and so on. For such reason, this paper proposed a novel type of integrated wheel mechanism that can be operated as a conventional driving wheel mode and hybrid wheel-leg mode in order to be negotiated in an unstable terrain environment. The mechanical effect of the proposed variable wheel mechanism was analyzed considering the geometric constraint and power requirement of the actuator for the transformation. In addition, we designed and manufactured the prototype of field-driving robot, which reliably control the variable wheel shape. Finally, the effectiveness of the variable wheel mechanism was verified by preliminary experimental approach.

Various robot platforms have been designed and developed to perform given tasks in a hazardous environment for the purpose of surveillance, reconnaissance, search and rescue, and etc. We have considered a terrain adaptive hybrid robot platform which is equipped with rapid navigation on flat floors and good performance on overcoming stairs or obstacles. Since our special consideration is posed to its flexibility for real application, we devised a design of a transformable robot structure which consists of an ordinary wheeled structure to navigate fast on flat floor and a variable tracked structure to climb stairs effectively. Especially, track arms installed in front side, rear side, and mid side are used for navigation mode transition between flatland navigation and stairs climbing. The mode transition is determined and implemented by adaptive driving mode control of mobile robot. The wheel and track hybrid mobile platform apparatus applied off-road driving mechanism for various professional service robots is verified through experiments for navigation performance in real and test-bed environment.