Abstract
Electric powered wheelchairs (EPWs) are supposed to be widely spread in the near future. Many models are now available in the market, but unfortunately, it seems most of them are 'difficult-to-drive' because of their manipulating sensitivity. In our previous study, it was shown that the improvement of the manipulability of an EPW could be accomplished by adjusting its 'manipulating impedance' to that of the users' preference. In this article, an alternate and a considerably simple solution of the problem as stated above is introduced. When designing a control system for an EPW, one has to consider (1) realization of the manipulating comfort, and (2) treatments against parameter variations at the same time. The idea employed for assuring manipulating comfortability is the same as our previous study, but the method adopted for assuring robust performance against parametric variations is completely new. Key theorem and its proof will be given, that should form a theoretical basis of this article. Finally, we must say that the design method proposed here should not be restricted to the design of the control system for an EPW.
