Rotating Lorentz Force Magnetic Bearings’ Dynamics Modeling and Adaptive Controller Design

Abstract

To address the issues of our agile satellites’ poor attitude maneuverability, low pointing stability, and pointing inaccuracy, this paper proposes a new type of stabilized platform based on seven-degree-of-freedom Lorentz force magnetic levitation. Furthermore, in this study, we designed an adaptive controller based on the RBF neural network for the rotating magnetic bearing, which can improve the pointing accuracy of satellite loads. To begin, the advanced features of the new platform are described in comparison with the traditional electromechanical platform, and the structural characteristics and working principle of the platform are clarified. The significance of rotating magnetic bearings in improving load pointing accuracy is also clarified, and its rotor dynamics model is established to provide the input and output equations. The adaptive controller based on the RBF neural network is designed for the needs of high accuracy of the load pointing, high stability, and strong robustness of the system, and the current feedback inner loop is added to improve the system stiffness and rapidity. The final simulation results show that, when compared to the PID controller and robust sliding mode controller, the controller’s pointing accuracy and anti-interference ability are greatly improved, and the system robustness is strong, which can effectively improve the pointing accuracy and pointing stability of the satellite/payload, as well as provide a powerful means of solving related problems in the fields of laser communication, high score detection, and so on.

Analysis and Compensation of Lorentz Force Magnetic Bearing Magnetic Flux Density Uniformity Error

“…The angular rate of MSCSGs can be calculated by detecting the current in the coils of Lorentz force magnetic bearings (LFMBs) so that the accuracy of LFMB design and machining directly affect the angular rate measurement accuracy of MSCSGs [10][11][12]. The compensation of the LFMB magnetic flux density uniformity error (MFDUE) is an effective way to improve the angular rate measurement accuracy of MSCSGs because the magnetic flux density uniformity (MFDU) of LFMB coils' working air gap is the main factor affecting the current accuracy [13,14].…”

Design and Analysis of 5-DOF Compact Electromagnetic Levitation Actuator for Lens Control of Laser Cutting Machine

“…The magnetic levitation technology can realize force regulation without contact. In a multi-DOF driving system, the magnetic levitation technology is highly favorable for the following characteristics: (i) a compact structure as the driving force and torque are generated by an integrated maglev actuator; (ii) a high motion precision with active control and positioning errors compensation; (iii) the elimination of vibration noise owing to its non-contact advantage [5,6] The maglev actuators can be categorized into Lorentz actuators and reluctance actuators. Dyck [7] developed a 6-DOF magnetically levitated rotary table for micro-positioning.…”