Control of a high speed machining spindle via /spl mu/-synthesis

Due to high surface speed and active control capabilities, active magnetic bearings hold great promise for high speed machining spindles. Here, the control problem posed by this application is examined and the development of an advanced prototype is reviewed. A μ-synthesis framework is proposed for this problem and it is shown that the minimization of the susceptibility to machining chatter may be easily put into this framework. In addition to handling uncertainties in sensor and actuator components, this formulation may also include an uncertainty representing the range of cutting tools for the spindle. As the machining spindle is still undergoing preliminary testing, experimental results are presented for another magnetically suspended rotor which strongly indicate the effectiveness of the proposed design procedure.