The spherical induction motor eliminates the robot's mechanical drive system.

The SIMbot robot features an elegant motor with just one moving part: the ball. The only other active moving part of the robot is the body itself. A spherical induction motor (SIM) eliminates the mechanical drive system and can move the ball in any direction using only electronic controls. These movements keep SIMbot’s body balanced atop the ball.

The rotor of the spherical induction motor is a precisely machined hollow iron ball with a copper shell. Current is induced in the ball with six laminated steel stators, each with three-phase wire windings. The stators are positioned just next to the ball and are oriented slightly off vertical. The six stators generate travelling magnetic waves in the ball, causing the ball to move in the direction of the wave. The direction of the magnetic waves can be steered by altering the currents in the stators.