“…This can be realized either by robust controller synthesis techniques, Lee and Chung [1998], Tsao et al [2000], Li and Tsao [2001], Steinbuch [2002], Osburn and Franchek [2004], Kim and Tsao [2004], Steinbuch et al [2007], Dietz et al [2007], or by adaptive methods, Bodson and Douglas [1997], Bodson [2001], Guo and Bodson [2005], Serrani et al [2001] as specialized to sinusoidal disturbance rejection. When the frequency is measurable or estimable online, as is the case -for instance-in systems with rotational machinery, linear parametervarying (LPV) controller synthesis techniques can also be applied for robust and adaptive non-stationary sinusoidal disturbance attenuation, Dettori [2001], Du et al [2003], Hüttner et al [2005], Kulkarni et al [2005], Gruenbacher et al [2007]. Within the LPV control framework, it even becomes possible to systematically and simultaneously handle other performance objectives, as has been illustrated by .…”