Space magnetic field control based on active disturbance rejection generalized predictive control

Abstract

The combination of active magnetic compensation technology and magnetic shielding room is one of the key technologies for measuring magnetoencephalography. However, due to the non-uniform and asymmetric distribution of the residual magnetic field within the compact magnetic shielding room, the traditional active magnetic compensation system with single point feedback is limited. In this paper, a space magnetic field control for the active magnetic compensation system is firstly proposed, including six independent coils and six sensors, which can sequentially control the uniform and gradient magnetic field in three axes. Meanwhile, considering the three-axis magnetic field coupling and external disturbances of the system, the combination of active disturbance rejection generalized predictive control is designed as the control method for the system. Results show that the magnetic field uniformity has been improved by 38.2%, 42.7%, and 42.1% in the three-axis directions, respectively, compared with traditional single point feedback control, and there are significant improvements in magnetic field coupling and magnetic field disturbance suppression. This study contributes to creating a highly uniform and extremely weak magnetic field environment, promoting the development of magnetoencephalography.