1. Introduction
Direct detection of gravitational waves is of great signif- icance for discrimination of various gravitational theories, verification of general relativity, and discovery of its rich nonlinear effect, which is also one of the frontier research fields of basic physics [1]. Among all kinds of gravitational wave detectors, laser interferometric gravitational wave detectors have become the mainstream one due to its advantages of wide bandwidth and high sensitivity [2,3]. The strain amplitude of interferometer arms caused by extremely weak gravitational waves is about 10–21–10–23. In order to capture gravitational waves in a wide frequency band (from several hertz to several thousand hertz), it is necessary to suppress various noise interference [4,5]. Therefore, low frequency vibration isolation technology