A Fault Tolerant Control Approach to Three Dimensional Magnetic Levitation

By James Ballard

Contents

•Introduction•Levitation Concept•Fault Tolerant Techniques•Prototype•Validation of Simulations•Conclusions and Recommendations

Introduction

•Magnetic Levitation▫Magnetic Repulsion ▫Feedback Control

•Fault Tolerance (Safety)▫Hardware▫Dynamic

Levitation ConceptForce due to gravity

Force from ring magnetIx

Ix

Horizontal ring magnetForce component

xy

z

Feedback Control Loop

•Proportional Gain•Pole Placement•Proportional, Integral, Differential (PID)

Proportional Gain Feedback Control

From mathematical analysis:

•Positive gain: No negative poles

•Negative gain: Positive pole

•Unstable levitation

Pole Placement Feedback Control

•Stable response achieved (P1=-80, P2=-100)•Gain values too high for embedded system

PID Feedback Control

•Stable levitation achieved•Gain values suitable for embedded system

𝐾𝑝=2 𝐾𝑖=0.22 𝐾𝑑=7.69

Dynamic Redundancy

Hardware Redundancy

The Prototype

Validation of Simulation: Stable

Simulation

Prototype

𝐾𝑝=2 𝐾𝑖=0.22 𝐾𝑑=7.69

Validation of Simulation: Unstable

Simulation

Prototype

𝐾𝑝=3 𝐾𝑖=2 𝐾𝑑=1

Dynamic Redundancy Test

Conclusions and Recommendations

•Naturally unstable

•PID control most suitable

•Fault tolerant techniques prevent system failure

Future Work

•Improved hardware redundancy

•Development of an observer

•User Interactivity

Thank you for listening