The brief presents a reliable 1-out-2 reduced order control design strategy for a cable-stayed bridge benchmark using two overlapping subsystems and the linear quadratic Gaussian (LQG) design. Reliability with regard to controller failures is considered. Local controllers are designed for reduced order subsystems of expanded system. They are implemented and evaluated on the original overall system model. Two different sets of numerical experiments of reliable control design within 1-out-2 controller failure structure have been systematically tested using a SIMULINK scheme and compared to the benchmark sample centralized LQG design. The performance of the reliable control design has been assessed by means of given benchmark evaluation criteria. The dynamics of the closed-loop benchmark model with this multiple controller exhibits an acceptable behavior though slightly worse than in the centralized case. Thereby, the main result is a practical well working 1-out-2 reliable controller designed for a real world large-scale system. The significance of this new strategy lies in its practical systematic approach for reliable control design for large scale systems.

Civil Engineering structures are already an important part in the Smart Cities concept. In connection to this, integration of new technologies is under way in the field of Structural Engineering as in all Civil and Buildings/Bridges Engineering. One of the main goals is to protect structures from possible harm from earthquakes. In order to achieve this goal, Optimal Active Control has been proposed and used with a high degree of success. However, the application strategies are continuously improving. A strategy consisting in simplifying the Optimal Active control for full states has been proposed by the authors and relatively recently modified for an increased efficiency. That was a theoretical research taking into account the possibility to reduce the order of magnitude of matrices involved in computations. The present paper is assuming the previous theoretical result and simulates its application to the structural model of a ground floor plus ten floors building specially designed for this purpose. The reinforced concrete frame building’s behaviour is analysed under seismic actions. Efficiency and the control strategy are observed in different scenarios. The structural response is revealing that the new strategy is working faster in limiting the effects of earthquake input. In addition, the reduced computational time leads to a faster control and smaller phase-shift in practical use.

The objective of this investigation is to present a decentralized control design for a cable-stayed bridge benchmark which was recently proposed within the structural control community to design and compare control schemes. The cable-stayed bridge has two towers as main structural elements. This naturally suggests the decomposition of a finite element overall dynamic model into two disjoint subsystems by assuming that the overall dynamics is determined mainly by the behavior of the subsystems and that interconnections have only a small dynamic effect. The idea of decentralization of control has been numerically tested using a SIMULINK scheme and compared to the benchmark sample centralized control design using the LQG design. The performance of the decentralized control design has been assessed by means of given benchmark evaluation criteria, eigenvalue analysis and time responses. The dynamics of the closed-loop benchmark model with the local controllers exhibits an acceptable behaviour though slightly worse than in the centralized case.