A model for signal processing and predictive control of semi-active structural control system

Abstract

The theory for structural control has been well developed and applied to perform excellent energy dissipation using dampers. Both active and semi-active control systems may be used to decide on the optimal switch point of the damper based on the current and past structural responses to the excitation of external forces. However, numerous noises may occur when the control signals are accessed and transported thus causing a delay of the damper. Therefore, a predictive control technique that integrates an improved method of detecting the control signal based on the direction of the structural motion, and a calculator for detecting the velocity using the least-square polynomial regression is proposed in this research. Comparisons of the analytical data and experimental results show that this predictor is effective in switching the moving direction of the semi-active damper. This conclusion is further verified using the component and shaking table test with constant amplitude but various frequencies, and the El Centro earthquake test. All tests confirm that this predictive control technique is effective to alleviate the time delay problem of semi-active dampers. This predictive control technique promotes about 30% to 40% reduction of the structural displacement response and about 35% to 45% reduction of the structural acceleration response.

Seismic Proofing Capability of the Accumulated Semiactive Hydraulic Damper as an Active Interaction Control Device with Predictive Control

“…Then the dynamic equilibrium equation of motion for the systematic organization of the ASHD as the AIC is derived from the unlocked status and the locked status of the interactive IE. In order to improve the seismic proofing capability of this proposed new AIC, a predictive control method [19,20] is applied to improve the energy-dissipating defects of the ASHD. Then, to test and verify the seismic proofing capability of the proposed AIC with and without predictive control, a full-scale two-story one-bay steel structure is tested on a shaking table in multiple forms, namely, the bare structure and the structure with various stiffeners added at different floors and with passive control, synchronous control, and asynchronous control and also with or without predictive control, under excitation of the El Centro and Kobe earthquake records with various peak ground acceleration rates.…”

“…where { } is the vector of structure displacement: Consequently, a new matrix of coefficient regression system [ ] is a constant matrix depending on the number of sampling points and regression ranks but independent of time or vector of data queue: Then, the optimal displacement̂= { }⋅{ } can be estimated based on this equation. [19,20]. The optimal displacements can be easily predicted usinĝ= { } can be stored in computer memory for predicting the real-time velocity or regressing velocity at any arbitrary time step; that is, the optimal velocity for previous time steps from the current time can be estimated by multiplying { } with the derivative of the displacement vector shown as (A.12).…”

“…According to previous research [16] on applying the Semiactive Hydraulic Damper as an Active Interaction Control device, the hysteretic loops of a single floor test structure under excitation by external earthquake records show a "time delay" phenomenon. In order to improve the seismic proofing capability of this proposed ASHD as AIC, a predictive control method for a Semiactive Hydraulic Damper is applied to reduce the time delay [19,20]. This predictive method was proposed by Shih and Sung [19,20] to diminish the time delay and improve the seismic proofing capability of an ASHD.…”

“…In order to improve the seismic proofing capability of this proposed ASHD as AIC, a predictive control method for a Semiactive Hydraulic Damper is applied to reduce the time delay [19,20]. This predictive method was proposed by Shih and Sung [19,20] to diminish the time delay and improve the seismic proofing capability of an ASHD. The structural responses of a test building under external excitation, namely, displacement, velocity, and acceleration, in a previous step are used to establish the signals for the next step.…”

“…Nevertheless, "time delay" phenomena occur in research achievements [16]. In order to improve this kind of problem, the predictive control method proposed by Shih and Sung [19,20] was applied to improve the seismic proofing capability of the proposed AIC. In this study, a theoretical analysis model is derived for ASHD and converted to AIC based on the concept of AIC.…”