Maglev Linear Motion Platform

Overview

Magnetic levitation looks like magic, but it is really a control problem: an electromagnet pulling a permanent magnet upward is an inherently unstable system — too close and it snaps shut, too far and it falls. The only way to hold the gap is to measure position continuously and correct the coil current faster than the instability grows.

This Individual Project Pursuit (IPP) with Prof. Kwee Yan Teh at SJTU is my long-running attempt to build that loop from first principles — no maglev kit, no black-box controller.

What I built

• Analog stabilization circuitry for 1D control of the levitating platform: a Hall-effect sensor reads the field strength (a proxy for the air gap), and the conditioned signal drives PWM-controlled electromagnets for proportional servo control.
• Replicated the MIC502 PWM controller chip on an Arduino. The fixed-function analog IC worked, but tuning meant swapping passive components. Reimplementing its behaviour in firmware made the control loop parameters editable in code — a much faster iteration cycle.
• Mechanical design in SOLIDWORKS: multiple electromagnet mounting platforms and structural supports, iterated specifically to keep the solenoid axis vertically aligned — misalignment shows up immediately as lateral drift the 1D controller cannot reject.

Why it's interesting

This project sits exactly at the intersection I care about: electromagnetics, analog electronics, embedded firmware, and mechanical design all have to agree with each other or the platform falls. It is the most honest feedback loop I know — the hardware literally drops when you get the engineering wrong.

Current state

The platform achieves stable 1D levitation under the Arduino-based controller. Next steps are characterising the loop's disturbance rejection and extending the design toward controlled linear motion along a rail of coils.