Abstract
The sensitivity function of feedback control systems is recommended for AMB (Active Magnetic Bearing) rotors to evaluate the stability margin. However, we need to predict the Q-value before rotor operation. In this paper, the sensitivity and the Q-value are discussed and the difference is made clear. How to obtain the Q-value from the open loop transfer function is also discussed. In this experiment the open loop transfer functions of the AMB system controlled by the mode separation control method was measured. Q-value peaks measured by open loop transfer functions agreed with Q-value calculated by closed loop transfer functions which is commonly used.
