Tuneable H-Inf. Vibration Control in Rotor/Magnetic Bearing Systems Using Parameter Dependent Shaping Functions

In this paper, a method is presented for the derivation of tuneable multivariable controllers for application to a magnetic bearing/rotor system. Controller design specifications are considered that use H¥ optimisation criteria with linear parameter dependent shaping functions. Linear matrix inequality (LMI) techniques are used to synthesise controllers that satisfy the H¥ design specification over the range of parameter values using a convex interpolation of vertex controllers. In this way the design parameters that determine the shaping functions can be adjusted on-line to tune the performance and robustness characteristics of the controller. Specific performance measures that are considered are those of rotor synchronous vibration levels, transmitted force levels, base motion rejection, as well as controller stability margins. The effectiveness of such an approach for the synthesis of tuneable H¥ controllers for a rotor/magnetic bearing system is evaluated.