REAL-TIME ITERATIVE CONTROL METHOD RESEARCH OF SHAKING TABLE

Offline iterative control (ICS) is often used in shaking table test to accurately reproduce earthquake waveform. However, multiple iterations will cause cumulative damages to vulnerable test specimens, and the continuously changing dynamic characteristics of the nonlinear test specimen will also lead to decrease of control accuracy of the ICS. To solve the problems, a high-accuracy real-time iterative control method (HRICS) based on system matrix correction is proposed. This method identifies the system matrix online upon the real-time data measured during the loading process, then selects the correction strategy accordingly, and finally evaluates the identification accuracy of system matrix by matrix accuracy evaluation indices. If the system matrix accuracy meets the requirement, the system matrix is updated upon frames or frequency points correction strategy, so that the response signal can reproduce the target waveform with high accuracy. The HRICS method is attested by shaking table test, and the control performance under nonlinear test body is studied by numerical simulation. The results indicate that the HRICS method using the frequency point correction strategy shows the best control effect. The reproduction accuracy of the HRICS method is significantly better than that of the ICS method after its first iteration.