Semi-active control of building structures under seismic action with faulty MR dampers and sensors

In semi-active control of structures, sensors and dampers may fail in earthquake. Sensor malfunctioning mostly causes a constant offset in true signals and shifts the mean value of the recorded parameters, but a fault in a damper may reduce its effectiveness and change the mean and variance of the force that should be applied. To date, many studies have investigated the fault effect on control devices. They have mainly focused on the faults that affect the signals' mean values (additive fault). However, some faults may also change their variance (multiplicative fault). These faults' identification and control require a different strategy. This study introduces a newly designed active fault-tolerant control system (AFTCS) to identify and accommodate simultaneous multiplicative damper fault and additive sensor fault during earthquake. To do that, by dividing the structure into two subsystems, sensor and damper fault effects are separated. Then, by designing an observer based on dynamic neural network (DNN) for each subsystem, faults on control devices are estimated. Later, the true responses of the structure are obtained and finally, the proposed fault-tolerant controller accommodates damper fault effects. The AFTCS's performance was validated for different fault scenarios in a three-story building structure with magneto-rheological (MR) dampers.