Precise control of a four degree-of-freedom permanent magnet biased active magnetic bearing system in a magnetically suspended direct-driven spindle using neural network inverse scheme

Abstract

The capacity of improving the control accuracy and dynamic performance of a four degreeof-freedom (DOF) permanent magnet biased active magnetic bearing (PMBAMB) system is critical to developing and maintaining a high precision application in a magnetically suspended direct-driven spindle system. The 4-DOF PMBAMB system, however, is a multivariable, strong coupled and nonlinear system with unavoidable and unmeasured external disturbances, in addition to having parameter variations. The satisfactory control performance cannot be obtained by using traditional strategies. Therefore, it is important to present a novel control scheme to construct a robust controller with good closed-loop capability. This paper proposes a new decoupling control scheme for a 4-DOF PMBAMB in a direct-driven spindle system based on the neural network inverse (NNI) and 2-degreeof-freedom (DOF) internal model control method. By combining the inversion of the 4-DOF PMBAMB system with its original system, a new pseudolinear system can be developed. In addition, by introducing the 2-DOF internal model controller into the pseudolinear system to design extra closed-loop controllers, we can effectively eliminate the influence of the unmodeled dynamics to the decoupling control accuracy, as well as adjust the properties of tracking and disturbance rejection independently. The experimental results demonstrate the effectiveness of the proposed control scheme.

Design and analysis of interior composite-rotor bearingless permanent magnet synchronous motors with two layer permanent magnets

“…First, we reference the equation used in inner radial-rotor BPMSMs to estimate the thickness of double layer PMs. According to (1), the reference range of PMs thickness for proposed machine can be given as…”

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A Bearingless Induction Motor Direct Torque Control and Suspension Force Control Based on Sliding Mode Variable Structure

“…The basic principle of inverse system method is to compensate the controlled object as a system with a linear transfer relationship by using the inverse system of the controlled object, then, to synthesize the system according to the linear system theory, and to realize the decoupling in nonlinear systems [24,25]. The necessary and sufficient condition for the system to be reversible in the neighborhood of ( 0 , 0 ) has vector relative order = ( 1 , 2 , . .…”

Torque modeling and characteristic analysis of electromagnetic piezoelectric hybrid-driven 3-degree-of-freedom motor

“…[20][21][22][23] Piezoelectric-drive multi-degree-offreedom motor is immune to external electromagnetic interference, which provides the possibility of electromagnetic piezoelectric hybrid-drive multi-degree-of-freedom motor development. The electromagnetic-drive multi-degree-of-freedom motor 24,25 has relatively complicated structure, the magnetic field is difficult to control, the control and positioning accuracy is low, the torque output by the rotor is difficult, and the torque loss is large. Piezoelectric-drive multi-degree-of-freedom motors have problems such as low lifetime and performance affected by fixed-rotor friction materials.…”