Characteristic Model Based All-coefficient Adaptive Control of a Flexible Rotor Suspended on Active Magnetic Bearings

Active magnetic bearings (AMBs) have been used in many high-speed rotating machinery ap-plications. Because of the nonlinear characteristics of magnetic bearings and complex dynamics of the flexible rotors, the problems of stabilization and disturbance rejection need to be exten-sively addressed for their smooth operation over a wide operating speed range. Conventional controller such as the proportional-integral-derivative (PID) design has played a major role in most AMB related applications. Although it is easy to implement, there exist limitations and drawbacks. The µ -synthesis approach can fulfill the requirement of robust performance, but it relies on the plant and uncertainty models, which are sometimes difficult to acquire for practical systems. This paper explores the use of the characteristic model based all-coefficient adaptive control (ACAC) method to stabilize a flexible rotor AMB system. This new control method does not require an actual model of the system. Both simulation and experimental results have shown its strong potential to perform well in spite of its simplicity.