Keeping chattering effect sufficiently low with new quasi-sliding mode control for building structure

Existing sliding-mode control methods for reducing seismological response of building structure, such as those of Cai et al^[5] and Zhao et al^[6], suffer, in our opinion, the shortcoming that it is almost very difficult to avoid excessive chattering effect. Therefore we propose new quasi-sliding mode control laws that can not only reduce seismological response but can also avoid undue chattering effect. In the full paper, we explain in detail the application of the quasi-sliding mode control methods to the control of seismologically excited structural systems. In this abstract, we just add some pertinent remarks to listing the following three topics of explanation: (1) the motion equation, (2) the determination of switching surfaces, (3) the design of control laws; under topic 3, we derive eq.(6) for the quasi-sliding mode control law involving saturation function and derive eq.(8) for that involving relay function. Finally we give numerical simulations for MDOF (Multiple-Degree-of-Freedom) shear building model containing an active brace system. The results of seismological response are shown in Figs.2, 3 and Tab. 1 for control law eq.(6) and control law eq.(8); they show that, like Refs. 5 and 6, seismological responses can be markedly reduced. The results for chattering effect are given in Fig.4; Fig.4(a) is for Refs. 5 and 6, Fig.4(b) is for control law eq.(6), and Fig.4(c) is for control law eq.(8); Fig.4 shows preliminarily that our quasi-sliding mode control laws can keep the chattering effect sufficiently low but, in this case, Refs.5 and 6 cannot do so.