Design, Development and Cascaded Control of Magnetic Levitation System With Differential Electromagnetic Actuators. Masters thesis, King Fahd University of Petroleum and Minerals.

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Arabic Abstract

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English Abstract

Electromagnetism forms the scientific foundation for magnetic levitation, a technology enabling frictionless and contact-free actuation across diverse engineering domains. Modern applications—particularly in space systems—demand micro-vibration suppression to protect sensitive payloads affected by disturbances that can exceed 0.1 g, span frequencies above 3 Hz, and produce millimeter-scale displacements. Existing passive isolators lack low-frequency attenuation capability, whereas active systems require accurate sensing, robust controllers, and stable electromagnetic actuation. These stringent requirements motivate the development of a one-degree-of-freedom magnetic levitation platform with differential electromagnets, accurate sensing, and low-noise signal conditioning capable of supporting both modeling and real-time control evaluation. A detailed mathematical model of the magnetic levitation system is constructed by linearizing the electromagnetic force dynamics around an operating point. Empirical calibration refines key parameters to ensure high-fidelity representation of the differential electromagnets. The model incorporates the electrical, magnetic, and mechanical subsystems, along with filtering to mitigate sensor noise. Using this validated linear model, a single-loop position-only controller is initially designed and tested in Simulink. Simulation studies include step responses, tracking tests, and disturbance injections to evaluate stability, settling behavior, overshoot, and control effort. These early results serve as a baseline for assessing system limitations—particularly the sensitivity to oscillations, high coil-current demands, and reduced disturbance rejection—highlighting the need for enhanced control architecture. To bridge the gap between non-real-time simulation and embedded control execution, the proposed control strategy is ported to an OPAL-RT real-time simulator for Software-in-the-Loop evaluation. The single-loop controller is executed with deterministic timing to confirm stability and performance under real-time constraints. SIL experiments include step-response testing, variable reference tracking, and chirp-based disturbance-rejection analysis. The close agreement between SIL outputs and pure Simulink simulations verifies the correctness of the control design, validates timing robustness, and ensures that the controller behaves consistently before hardware implementation. This stage provides a crucial safety layer that prevents hardware risk and identifies controllability and performance issues before physical testing. Following successful SIL verification, a physical 1-DOF magnetic levitation test rig is developed using differential electromagnets, an inductive position sensor, and a Hall-effect current sensor. The cascaded dual-loop position–current architecture—comprising an inner current-regulation loop and an outer position-feedback loop—is implemented on a TI LaunchXL microcontroller, with measurement acquisition handled by NI DAQ. Rigorous experiments compare the dual-loop controller to the previously studied single-loop architecture. Results show that the dual-loop system reduces coil-current demand, improves transient smoothness, enhances damping, and provides superior rejection of wideband disturbances. Frequency-domain analysis confirms improved gain and phase margins, smoother Bode characteristics, and reduced sensitivity around resonance, validating the effectiveness of adding an inner current loop. This final stage experimentally demonstrates the superiority of the cascaded controller and sets the foundation for advancing toward multi-degree-of-freedom maglev systems.

Item Type:	Thesis (Masters)
Subjects:	Systems Physics Electrical Mechanical
Department:	College of Engineering and Physics > Control and Instrumentation Engineering
Committee Advisor:	Ahmad, Sarvat
Committee Members:	Salem, Bashmal and Amrr, Syed Muhammad
Depositing User:	TASNEMUL NEHAL (g202318850)
Date Deposited:	28 Dec 2025 11:56
Last Modified:	28 Dec 2025 11:56
URI:	http://eprints.kfupm.edu.sa/id/eprint/143912