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Robustness of Simple Adaptive Control for Seismic Protection of Bridges in Presence of Faulty Sensors
Rachel Wysard Soares, Luciana Ribeiro Barroso

Last modified: 2023-05-15


Simple adaptive control is an implicit model reference adaptive control strategy that has been utilized successfully for reference tracking and control of large scale structural systems. The method is appealing for this type of structures given it allows for adoption of a lower order model reference when compared to the plant, and avoids complicated online identifiers. Among the successful applications of simple adaptive control, there is the control of seismically-excited bridge structures. In this particular application, the structural system size and complexity and the many uncertainties involved during the design phase and its service life makes simple adaptive control a viable solution to guarantee performance when it comes to seismic response mitigation. Bridges present some level of damage and cracking along their service life, are subjected to a variety of considerable disturbances, and have intrinsic parameters that are very difficult to predict during the design phase. In previous studies, simple adaptive control was proven to be an alternative to provide the necessary amount of robustness, and guarantee control performance in face of the aforementioned factors. However, one specific issue remains unexplored when it comes to application of simple adaptive control for seismic protection of bridges, that is the control robustness in face of faulty sensors. Given the difficulties that involve maintenance of bridges, especially during severe weather, it is possible that during the occurrence of an extreme event some sensors do not operate properly. The present study investigates the robustness of the simple adaptive control of a seismically excited highway bridge when in face of faulty sensors. It considers sensors with signal drift, the total absence of signal, and sensors transmitting purely noise in six different combinations of malfunction scenarios. The bridge is subjected to a set of seven historic representative earthquake records and the performance and robustness of the control method is assessed. From the observation of results, it becomes evident that simple adaptive control is able to reduce the dynamic responses of the bridge, and that the strategy is able to sustain performance very well in face of sensor malfunction. The maximum error between the controlled response from all sensors working perfectly and in a scenario of faulty sensors is of 3.6%, and that is considering 40% of the sensors providing faulty signals. It can be concluded that the method is robust in a scenario of sensors malfunction and that it is a promising control solution for excessive response mitigation of seismically-excited bridge structures.