From the pictures that are 2 electric cart that has developed about the oils to reduce constraints on the motion, that is, using a belt as a powered wheelchair, which will make it possible to skip a large barrier.
From Figure 2, a power wheelchair with the development of a driver. In order to reduce the limitations of the movement. There is a belt-driven cart. This allows a huge hurdle. Or you can get up and down stairs.
From the second image is electric wheelchair with development about oils. In order to reduce the limitation of motion. That is, use the belt driven wheelchair. Which will be over obstacles with a large.