On the compensation of incremental encoder imperfections for motion control: a DC motor case-study

We address the problem of rotational velocity and acceleration estimation from incremental encoders in the presence of sensor imperfections. In the area of motion control, measurements of shaft velocity and acceleration are often affected by large disturbances with a period of one revolution that arise from sensor imperfections and degrade the performance of most closed-loop control algorithms. We present an algorithm to identify and remove such periodic perturbations online, without the need of error compensation look-up tables, and without assuming constant velocity. The proposed algorithm is evaluated via open-loop experimental tests, and its implementation in closed-loop control applications is investigated via numerical simulations through a DC motor case-study.