10. Motion Encoding

The previous chapter introduces PWM control for DC motors. We also realized that we cannot deduce the rotational speed of a DC motor just using the PWM duty cycle. In fact, there is no way to theoretically compute the rotational speed of a DC motor precisely!

We need to rely on feedback to let a controller know exactly how fast a DC motor is rotating. More precisely, we need some feedback to know how fast a robot is moving.