Figure 11

Active-caster drive system and add-on drive mechanism. (a) Active-caster drive mechanism. The power from the motors is transmitted via gearboxes and gear trains to the wheel and steering shafts in order to generate the required velocity. To detect the wheel orientation ϕ, an absolute encoder was attached to the steering shaft. (b) A novel add-on drive mechanism. To satisfy the simulation results, a linear actuator with a 200 mm stroke was used, and the length of each link were the same as those listed in Table 1. By attaching this drive mechanism, the wheelchair could be electrically operated.