Cross-axis coupling suppression method based on TITO-SGPC for active magnetic compensation system

Abstract This study addresses the challenge of cross-axis magnetic field coupling in active magnetic compensation (AMC) system for magnetic shielding room (MSR), which limits control accuracy in weak magnetic environment. A three-input three-output (TITO) model of AMC system is constructed, and a simplified generalized predictive control (TITO-SGPC) is proposed, using attenuation sequence to reduce high-dimensional matrix operations. Experimental results show that TITO-SGPC suppresses cross-axis coupling magnetic field within 0.34 nT, achieving over 2.4 times higher suppression than traditional GPC. Compared with multiple-input multiple-output model predictive control (MIMO-MPC), the computational complexity is significantly reduced, the execution time and memory usage are reduced by 14 times and 2.2 times, respectively, and it has better disturbance suppression effect. This method overcomes the limitations of traditional decentralized control and computationally intensive MIMO methods by explicitly establishing a three-axis cross model, and uniquely balances coupling suppression and real-time performance. This study provides a modular and high-precision solution for biomagnetic measurement, enabling stable control in MSRs with different geometries and supporting advancements in weak magnetic measurement technology.