2019 Volume 8 Issue 2 Pages 256-262
Almost all motion control systems have low-stiffness parts, and exhibit resonance characteristics. In many cases, we use the systems at a lower frequency range than the resonant frequency. However, in some cases, we have to use them in the same frequency range as that of the resonance. Various researches have been conducted to suppress the vibration of resonant systems with feedback controllers. They are very effective, but we need to design dedicated controllers with special capabilities. On the other hand, a feedforward controller can change the zeros of the system, which in turn suppresses the vibration. In this paper, two examples that demonstrate the effect of feedforward controllers are introduced. They change the reference response of the systems and the limited pole placement method, which assigns the representative poles precisely, is used to assist the effect.
