Adaptive controller design and disturbance attenuation for a general class of sequentially interconnected SISO linear systems with noisy output measurements

We study the adaptive controller design for a special class of MIMO system, which is composed of arbitrary but a finite number of SISO linear subsystems under noisy output measurements, S₁, ..., S_m, sequentially interconnected with additional feedbacks. Using the design approach, we obtain a class of adaptive controllers which guarantees the boundedness of closed-loop signals with bounded exogenous disturbances, and achieves asymptotic tracking if exogenous disturbances are bounded and of finite energy. Moreover, the closed-loop system admits a guaranteed disturbance attenuation level with respect to the exogenous disturbance inputs, where the ultimate attenuation lower bound for the achievable performance level is equal to the noise intensity in the measurement channel of S₁.