Nonlinear Control of a Magnetic Levitation System Based on Coordinate Transformations

• Published in: IEEE access Vol. 7; pp. 164444 - 164452
• Main Authors: Ni, Fei, Zheng, Qinghua, Xu, Junqi, Lin, Guobin
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Attenuation; Control systems design; Control theory; Controllers; coordinate transformation; Coordinate transformations; disturbance attenuation; Dynamic characteristics; Feedback control; Feedback linearization; Iron; Linear control; Linear quadratic regulator; Linearization; Magnetic levitation; Magnetic levitation system; Magnetic levitation systems; Nonlinear control; Nonlinear dynamical systems; nonlinear feedback; Nonlinear systems; Performance enhancement
• ISSN: 2169-3536; 2169-3536
• DOI: 10.1109/ACCESS.2019.2952900

In this paper, a novel concept of nonlinear controller design is proposed, which is applicable to nonlinear systems subject to external periodic disturbances. At first, by employing a pioneering nonlinear coordinate transformation, a new nonlinear system model with expected dynamic characteristics is derived. Then, a corresponding linear system is achieved by means of linearization techniques at equilibrium points. Next, based on the results of classical linear control theory, a linear quadratic regulator is applied to the resulted linear system. Finally, the nonlinear controller can be obtained through the inverse nonlinear coordinate transformation of the linear feedback controller. The performance of the proposed method is validated on a magnetic levitation system and is compared with the classical linearization feedback control. Simulation results show that the proposed controller design assures enhanced performance in terms of both system stabilization and disturbance attenuation.