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Publication

Design Tools for the Robust Decentralised Control of Large-scale Systems with Time-delays

Book - Dissertation

A general approach is proposed to design decentralised, distributed, or overlapping control for multiple input multiple output systems with time-delays by viewing them as special cases of (structurally constrained) centralized controllers. This is done by introducing structural constraints within the optimization problem for tuning the controller parameters. However, this approach does not exploit the structure of the controller or system while computing the objective functions, thereby leading to a negligible reduction in computational complexity. As a next step, a structure exploiting method is proposed for a special class of problems, wherein delay coupled identical systems arranged in some network structure are to be controlled by identical decentralized, distributed, or overlapping controllers. By doing so, we improve the computational efficiency with the number of subsystems. The two approaches, which have been implemented in a publicly available software, support a wide variety of system models. The above-mentioned structure exploiting method reduces the overall design problem to a robust/simultaneous controller design problem for one parameterized subsystem, where the allowable values of the parameter arise from the network graph. We suggest treating these parameters as perturbations or uncertainties, contained in specific intervals or regions determined by the allowable topologies of the network. By using state-of-the-art optimization tools, we ensure that the achieved stability and robustness property, and the computational complexity of the controller design, are independent of the number of (identical) subsystems and the topology of the network. Furthermore, we propose an approach to design decentralised controllers for networked systems considering or optimizing the robustness against networked imperfections (possibly varying transmission delays, sampling which might be aperiodic, package lost, and noise).
Publication year:2020
Accessibility:Open