Active Disturbance Rejection-Based Radial Four-Degree-of-freedom Decoupling Control for Electromagnetic Bearing System

Electromagnetic bearings are widely used in military industry, transportation and other fields due to their advantages of no contact and no friction. However, there is a strong coupling between the radial four degrees of freedom (DOF), which makes it difficult to achieve high-speed, high-precision and stable operation. In order to solve this problem, this paper proposes an active disturbance rejection based decoupling control strategy. Firstly, according to the system structure, the mathematical model of the electromagnetic bearing is derived based on Newton’s second law. In the model, the coupling items among the different DOFs are regarded as external disturbance, which are further estimated by proposed extended state observer (ESO). Then, an active disturbance rejection based decoupling control strategy for electromagnetic bearing system is implemented by compensating the position controller. Finally, the decoupling-based control is verified by simulation results.