Multiple model adaptive control of a large flexible space structure with purposeful dither for enhanced identifiability

Dithering techniques for enhancing uncertain parameter identification with moving-bank multiple model adaptive estimation (MMAE) and control (MMAC) algorithms are analyzed. The dithering techniques and multiple-model adaptive algorithms are applied to the SPICE 2 flexible space structure. The dithering techniques studied include purposefully constructed square wave, sine wave and wideband noise wave forms. The impact of purposeful rigid-body slew commands on exciting the structure´s flexible bending modes is also investigated. Dither inputs into the structure are performed in an effort to enhance the open-loop identifiability of the uncertain parameter, namely a scalar multiplier on the undamped natural frequencies of the flexible bending modes. Correct identification of this parameter enables the MMAE and MMAC algorithms to quell any vibrations induced into the structure, in the face of varying parameter values. The results studied indicate that purposefully constructed dither signals enhance parameter identification significantly