Design and Analysis of Hardware Acceleration for Semi-Physical Simulation of Ground-Based Drag-Free Control

To meet the in-orbit performance verification requirements of a drag-free control system for gravitational wave detection satellites, this study develops a ground simulation platform using the H-infinity (H∞) control method in Simulink. The FPGA implementation accelerates the core algorithm of drag-free control. A frequency-domain linear robust control design is employed, with a frequency pre-warped bilinear transformation method used to discretize the multi-degree-of-freedom controller. The established control system model includes 18 degrees of freedom, with 12 from the dual test masses (TM) and 6 from the satellite body. The two test masses are spatially arranged in a symmetric configuration, and their control structure also exhibits symmetry. A rapid reconfigurable hardware architecture is utilized, and the Vitis Model Composer tool is employed to efficiently translate the Simulink algorithm model into hardware description language, reducing the processing delay of the core control algorithm to the nanosecond level. Through a 15-channel gradient test comparison, the FPGA platform maintains numerical equivalence with the Simulink platform (maximum error of 10−13). Experimental results show that the hardware acceleration improves dynamic response speed by an order of magnitude, achieving position control accuracy of ±5 μm and attitude accuracy of ±10 μrad, with overall processing latency at the microsecond level. This method provides a reliable engineering validation approach for ultra-precision control systems in gravitational wave detection.