INFLUENCE OF THE MOTOR FEEDBACK SENSOR ON AC BRUSHLESS SERVO DRIVE PERFORMANCES

This paper discusses the influence of the position feedback sensor technology in servo drive applications. Incremental encoders, resolvers, and sinusoidal encoders are considered. Different hardware and software techniques used for the processing of position measurement signals are presented. Advantages and drawbacks are discussed for each solution. The choice of the best suited position feedback sensor for a given motion control application mainly depends on the speed and position control requirements and on the motor type. The dynamic performances and the accuracy of speed and position servo loops are dramatically influenced by the position feedback sensor resolution and accuracy. These points are analyzed in detail in the paper. Stiffness, stability, servo loop bandwidth and response time are considered as performances evaluation criteria for a given servo drive equipped with various position sensors. Rotating and linear AC brushless servo motors are considered. Experimental results are given.