Wrap a computer around it

My doctoral thesis advisor, Dr. Tom Knight, imparted upon me many valuable pieces of wisdom. One aphorism was “wrap a computer around it”: instead of making a system more perfect, it’s often cheaper to use a computer to compensate for the imperfections.

For example, instead of making storage media absolutely perfect, it’s cheaper to throw a rather sophisticated processor into every hard drive or SSD that can compensate for the natural imperfections – and the inevitable degradation over time – inherent in physical storage media. The laws of nature conspire against highly ordered, perfect systems, so it’s cheaper and easier to accept the natural state of things and simply compensate for the bits that we find undesirable.

Motors are another everyday object that are difficult to perfect, but essential to everyday life. Subtle imbalances and asymmetries of a motor’s construction can lead to excess vibration and efficiency loss. While solutions exist to ‘wrap a computer’ around these problems, quite often the computer and the motor are two separate entities. However, in recent years, Moore’s Law has progressed to the point where microprocessors and sensors, powerful enough to ‘close the loop’ around a small brushless DC (BLDC) motor, can be essentially hidden within the motor’s physical size and power envelope. For negligible extra power and mass, a small computer can be wrapped around such motors to make them behave closer to ideal elements.