Figure 15

Experimental results (snapshots of a series of motions). (a) The wheelchair stopped in front of the step without brakes (b) A static wheelie motion was performed. (c) While the front casters hovered, the wheelchair performed a translational motion so that the front casters could climb over the step. (d) After the front casters climbed the step, the large wheels were made to hover above the ground at a height of 100 mm by cooperative control of the linear actuator and the active-caster. (e) By performing a translational motion, the large wheels climbed over the step. (f) By stretching the linear actuator, the wheelchair performed a static wheelie motion on the step. After that, for approaching the drive wheel to the step, the wheelchair performed a translational motion. (g) After the brakes of the large wheels were locked, the front casters landed at the same time that the active-caster climbed onto the step by cooperative control of the drive wheel and the linear actuator. (h) By performing a translational motion, the wheelchair moved on the step.