Silva-Navarro G., Amado-Cabrera A.

ABSTRACT In this paper is addressed the problem of semiactive balancing control of a Jeffcott-like rotor system on ball bearings, one of them supported on radial magneto-rheological (MR) dampers. The mathematical model of the rotor system results from a Jeffcott model and the dynamics associated to the MR dampers, whose properties depend on the current inputs (control actions). There are different models for MR dampers proposed in the literature (Bingham, Bouc-Wen, Spencer, Choi-Lee-Park, etc.), most of them experimentally validated. For control purposes we use the Choi-Lee-Park polynomial model, which is quite consistent with the nonlinear and complex hysteresis damper models and also simplifies the physical implementation. The semiactive control scheme is then analyzed and synthesized to manipulate the unbalance response of the rotor system, by means of a proper modification of the rotordynamics coefficients (damping and stiffness). It is performed a controllability and stability analysis of the overall rotor system, in order to propose a suitable semiactive control strategy based on sliding-mode control techniques. The control scheme also makes use of a local rotor speed control to improve the overall system response (rotor speed and acceleration scheduling), during run-up or coast-down, passing through the first critical speed. Some numerical simulations are included to illustrate the dynamic performance and robustness when the rotor is started and operated over the first critical speed.