Learning Robotics using Python - Second Edition

Motor and encoder

The robot that we are going to design is a differential-drive robot with two wheels, so we will require two motors for its locomotion. Each motor consists of quadrature encoders (http://www.creative-robotics.com/quadrature-intro) so that we can get motor rotation feedback data.

The quadrature encoder will send data regarding of the rotation of the motor as square pulses; we can decode the pulses to get the number of the encoder's ticks, which can be used for feedback. If we know the wheel's diameter and the number of ticks of the motor, we can compute the displacement and the angle of the robot that moved. This computation is very useful for us in our attempts to navigate the robot.