This paper presents a completely decentralized control scheme for the control of interconnected systems with unmodelled nonlinearity and interaction. The interactions due to the interconnection and the intrinsic nonlinearities associated with each subsystem are represented by aggregative deviations of state derivatives from their linearized nominal values of the decomposed subsystems. Then, based on a model following technique, the aggregative deviations are tracked by on-line improvement. The solution involves the design of the decentralized control giving each subsystem a near-optimal performance close to the decomposed, linearized optimal response and the generation of corrective signals for the aggregative deviations of state derivatives. This approach is completely decentralized and all the operations are subsystem based, therefore the burden of computations is reduced significantly. Moreover, the proposed control method is robust to modelling errors and is initial state independent. By the Lyapunov's direct method, a sufficient condition for the stability of the global system even under any structural perturbations is established. Computer simulations for the decentralized control of a two-link, θ-r manipulator are conducted. © 1990.
Mao, C. J., & Lin, W. S. (1990). Decentralized control of interconnected systems with unmodelled nonlinearity and interaction. Automatica, 26(2), 263–268. https://doi.org/10.1016/0005-1098(90)90120-7