High resolution position estimation for advanced motion control based on FPGA

This paper presents a new method to obtain high resolution position using the incremental encoder signal. In addition, the high resolution position has been used for velocity estimation and torque disturbance estimation by disturbance observer. FPGA implementation is performed using short sampling time, which offers high performance in the motion control algorithms. The high position estimation is produced by the normalization of the number of clock pulses per pulse encoder. Thus, the fractional step can be evaluated at every sampling time. So, the fractional step is integrated every sampling time to the incremental encoder signal. The position with high resolution reduces the noise in the velocity estimation and torque estimation; thus, their bandwidth can be increased. The proposed method is verified in a velocity control and force control based on disturbance observer.