An optimized Youla–Kucera parametrization with time-delay compensation in multirate parallel control for disturbance rejection up to Nyquist frequency

This paper addresses the control problem of a time-delay compensation method with multirate control in Youla–Kucera parametrization to reject disturbance. Such design methodologies not only enhance the disturbance rejection performance within the control bandwidth, but can also even break through the bandwidth to reject disturbance up to the Nyquist frequency . First, the time-delay function can be simplified to the real number ± 1 at the disturbance characteristic frequency by tuning the additional time-delay factor for compensation, resulting in alleviating the detrimental effects of time delays. Next, a multirate control mode is proposed to implement the fractional compensation condition for solving the time-delay alignment problem. Moreover, this paper presents a parallel design approach for Q filters, significantly attenuating beam jitter resulting from complex multi-frequency disturbances. Finally, to assess the proposed method for beam jitter attenuation, experiments were conducted on a line-of-sight stabilization testbed. The results demonstrate that the proposed method can effectively enhance the disturbance rejection performance in time-delay control systems. • A time-delay compensation method improves Youla–Kucera parametrization performance. • A multirate control approach solves the alignment issue in time-delay compensation. • The parallel Q filters design achieves rejection of multi-frequency disturbances. • The proposed method achieves disturbance rejection up to the Nyquist frequency. • Experimental validation was conducted on a line-of-sight stabilization testbed.