Laboratory validation of adaptive digital notch filtering

An adaptive control scheme for suppressing vibrations of large flexible structures is presented. The control scheme utilizes self-tuning digital notch filters to minimize the excitation of the system resonant modes by control forces. The notch filters are tuned so that their center frequencies coincide with the system resonant frequencies, which are identified using an FFT (fast Fourier transform) and a heuristic search technique. This enables the control system to adapt automatically to the variations or uncertainties in the dynamical characteristics of the plant. The control scheme is evaluated by means of a hardware-in-the-loop simulation using an analog computer to solve the plant equations of motion in real time. The resonant frequency detection and control functions are implemented in real time using commercially available signal analysis and digital control hardware. Conclusions regarding the performance, advantages, and limitations of this adaptive control scheme are presented, along with recommendations for further research and development