Simple robust design of Two-Degree-of-Freedom PID controller for tracking drives of Linear Servo Motors

A simple robust design method of a two-degree-of-freedom (TDOF) PID position controller is presented for linear servo motor (LSM) drives under load mass variation. A new calculation formula to determine all TDOF PID parameters suitable for positioning drives is shown. Using the calculation formula, one can easily design overshoot-less positioning drive systems by turning only two items: cutoff frequency of position control loop and crossover frequency of sensitivity and complementary sensitivity functions. In addition, the author shows a re-design method that entails adopting the above TDOF PID parameters to tracking drives. Experimental results on a vector-controlled single-sided linear induction motor (3-phase, 3-pole, 12-slot, 200-V, 16.1-A, 50-Hz) demonstrate the validity of the proposed method.