Filter Form of State Observer for Industrial Motion Control Systems

Measurement of motor position and speed has always been a problem due to limited resources and costs in industrial servo drive systems since the non-linear behavior of low-resolution and low-cost encoders, estimation of motor speed with conventional methods, and disturbances in wide frequency ranges in the servo system reduce the performance of the motion control system. Thus, for the last few decades, the main goal in motion control system design has become to assure that the highest quality could be achieved by increasing robustness for various torque disturbances, system noises, and uncertainties present in the drive system. This paper proposes the filter form of state observer to estimate the permanent magnet synchronous motor (PMSM) state variables, which ensures a fast and accurate estimation to enhance the performance of the motion control system. The proposed filter in this paper has been compared with the state observer and pulse count method, which are two popular methods in motor control applications, by conducting mathematical analysis and simulation study. Results gathered from these analysis conclude that an improvement on the time delay of estimation algorithm could very well be achieved.