Modeling and control of active seismic isolation systems with non-minimum phase zeros for gravitational wave detectors Integration internship

Abstract

This thesis investigates the origin of non-minimum phase zeros in the control of seismic isolation platforms, with a particular focus on gravitational wave detectors such as LIGO, Virgo and Einstein Telescope. These detectors require extreme precision, and even small parasitic dynamic effects can severely impair their sensitivity. Through a combination of analytical modeling, numerical simulations using MATLAB Simscape, and experimental validation, this study explores how the location and configuration of sensors and actuators affect the appearance and nature of transmission zeros. The results highlight the importance of structural geometry in mitigating tilt-horizontal coupling and show that careful sensor placement and mechanical decoupling are essential to achieving effective active control. The findings contribute to improving the robustness and bandwidth of control systems in next-generation detectors, with potential applications in other high-precision engineering systems.