Ball and Wheel

The 'Ball and Wheel' device (BW/AT) from XdTech is a device invented by our research team to foster creativity and problem solving among system and control engineers.

In this device an untethered ball rolls down the periphery of a wheel, and the angular velocity of the ball is controlled by controlling the drive to the wheel. Being highly non-linear, the angular velocity of the ball will not be constant for a given attitude of the ball. Therefore a two-channel control mechanism is required. The first channel drives the main motor that is connected to the wheel thus controlling the instantaneous position of the ball. The second channel (outer loop) controls the attitude of the ball's position sensor so as to control the angular velocity of the ball.

The system includes the electromechanical system, an integrated cabinet comprising a stand-alone controller, an analog interface unit, DC power supply, and power amplifier, a multifunction DAQ card and associated application software for digital control under Matlab®.