On the Stability properties of P(I)D-controlled motion systems

For motion controller design, the reduced plant model is used in which high frequency dynamics are neglected. However, the maximum achievable closed-loop bandwidth is limited by the very same dynamics. The extent of their influence depends of the character of the high frequency modes. Another aspect that has an impact on the stability of the closed-loop system, is the damping present in the plant. The influence of the type of high frequency dynamics, the damping thereof, and the P(I)D controller bandwidth on the closed-loop stability is addressed in this paper. The results provide the reader with design rules of thumbs concerning the maximum achievable cross-***over frequency.