Optimal design of rim motor for electric powered wheelchair

The authors aim to provide a novel design of rim motors for electric wheelchairs, using the conventional rim as the motor on each wheel. The rotor of the rim motor is a conventional hand rim plugged inside its tube with a series of magnets of alternate N and S poles. Two sectors of arc stator are designed facing the inner side of the rim. This configuration enables a larger force-arm that multiplies the force exerted along the rim to produce a larger torque than the conventional hub-in motor of smaller radius. An optimal design procedure for a rim motor would make electric powered wheelchairs foldable, light, fuel-efficient and easy to operate. Experimental results show that the prototype rim motor satisfies the required specifications in terms of speed, torque, torque density and torque ripples. This rim motor provides a promising option for actuators and is a revolutionary product for electric powered wheelchairs. © The Institution of Engineering and Technology 2007.