Force characteristics analysis and active disturbance rejection control of ultra-precision axial positioning platform

To address the requirements of short stroke, high precision, high dynamic response, and strong disturbance rejection for ultra-precision axial positioning platforms (UAPP) in micro-gravity space optical payload ground testing environment, a UAPP scheme that organically integrates a actuator/bearing configuration and a high-performance control algorithm is proposed. The three-dimensional finite element method is used to deeply investigate the force and stiffness characteristics of the four-quadrant permanent magnet array Lorentz force motor and unequal width Halbach array magnetic bearing as they vary with displacement, laying the foundation for establishing an accurate dynamic model and performance analysis. A composite nonlinear feedback active disturbance rejection control based on a nominal auxiliary model (NAM-CNFADRC) algorithm is proposed. Both simulation and experimental results demonstrate that, compared to proportion-integration-differentiation and classic second-order linear active disturbance rejection control algorithms, NAM-CNFADRC exhibits significant advantages in tracking accuracy, maximum overshoot, settling time, and disturbance rejection.