Abstract:
The frequency bandwidth expansion compound shaking table (FBECST), as a new type of seismic simulation shaking table, provides an effective solution for achieving long-stroke and wide-band excitation. The FBECST is composed of a long-stroke shaking table and a high-frequency shaking table stacked vertically, which has a high system complexity. It is a prerequisite to design appropriate compensation control methods for achieving high-precision tracking control of FBECST. An overall error compensation control method based on feedforward correction is proposed, and the convergence and stability are analyzed. A method for determining the overall error feedback gain is proposed based on the gain margin theory. Taking the inverse compensation (IC) and offline iterative control (OIC) as baseline methods, the effectiveness and advantages of the proposed method are verified by comparison. A series of experiments demonstrate that the proposed method performs better than IC and OIC in both time-domain and frequency-domain, particularly in seismic wave reproduction, where its advantages are especially pronounced. The proposed method achieves high-precision compensation control of the FBECST system through only one identification and algorithm design process, minimizing its influence on the specimen. This paper offers robust support for the study and engineering application of model-based compensation control methods of FBECST.