A new equivalent-input-disturbance approach for active control of buildings

Abstract

This study presents a new control system, which is an extended EID (EEID) method, for active structural control (ASC) based on the equivalent-input-disturbance (EID) approach. This method considers both the absolute acceleration and relative displacement of a building. In the last few decades, some advanced control methods are also applied for ASC. Suppressing absolute acceleration is important to protect properties and people from a large earthquake. However, conventional EID control method only considered the relative displacement but not absolute acceleration. In contrast, EEID considers both the absolute acceleration and the displacement. Section 2 explains the EEID and EID method. This section shows the whole EEID control system, and how to calculate an EEID of a system. Section 3 considers the transfer function of EEID from the disturbance input channel to the state of the control system. This section shows the EEID system has two control parts, which are the feedforward and feedback control parts. The feedforward part consists of the observer and the low-pass filter and the feedback control part consists of the feedback controller gain and the control input matrix. Section 4 uses a single degree-of-freedom shear building model to compare the control performance of EID and EEID for a displacement and an absolute acceleration. This section explains that the observer gain of EID only adjusts the constant term of the transfer function of the disturbance to the displacement. In contrast, the observer gain of EEID not only influences the constant term but also the dynamic characteristic term. Section 5 shows the results of numerical examples. This section uses three models that ordinal frequencies are 0.5, 1.0 and 2.0 Hz to demonstrate the validity of EEID. The results show that the control performances for absolute acceleration of NC, FB, EID and EEID are almost all the same especially for low frequency. In contrast, the results of the frequency responses for the transfer function from the disturbance to the displacement shows that the control performance for displacement of EEID is much better than that of the NC, FB and EID. There is a trade-off between the absolute acceleration and the displacement in addition to the control performance for absolute acceleration of the EEID being the same as the EID. However, despite this, the control performance for the displacement of the EEID is much better than that of the EID. Section 6 is the conclusion of this paper. The advantages of EEID are as follow: 1) EEID consists the two control parts, which are the feedforward and feedback control parts. Thus, the control performance for displacement of EEID is much better than that of the conventional feedback control system. 2) The observer gain of EEID adjusts not only the constant term but also the dynamic characteristic term in the transfer function from the disturbance to the displacement. Thus, the control performance for displacement of EEID is much better than that of the EID. 3) There is a trade-off between the control performance for the absolute acceleration and the displacement. The control performance for displacement of EEID is much better than that of the EID while the control performance for absolute acceleration of EEID is the same as the EID.