# Magnetic Levitation

See it in action

## Bring the Maglev Train Technology Into the Lab

The Quanser Magnetic Levitation (MAGLEV) is a single degree of freedom electromagnet-based system that allows users to levitate a ball vertically up and down. This classic electro-mechanical experiment with interesting nonlinear dynamics and control challenges is ideal for teaching modeling, linearization, current control, position control, and using multiple loops (i.e. cascade control). Using the system, students learn how to:

• model the system from first principles in order to obtain the two open-loop transfer functions characterizing the system, in the Laplace domain
• linearize the obtained non-linear equation of motion about the quiescent point of operation
• use pole placement to design a proportional-plus-integral (PI) controller for the MAGLEV electromagnet current
• use pole placement to design a proportional-plus-integral-plus-velocity (PIV) controller with feed-forward action for the MAGLEV levitated ball position
• implement the controllers in real-time and evaluate their actual performances
• numerically determine the system's actual closed-loop poles, by considering the coil current control system's dynamics

In addition to teaching control concepts, the Magnetic Levitation can be used for research in various areas, including such as mutli-variable, gain scheduling, and nonlinear control.

How It Works

The Magnetic Levitation is an electromagnetic suspension system acting on a solid one-inch steel ball. The electromagnet, located at the upper part of the device, is capable of lifting the steel ball from its pedestal and sustaining it in free space. The electromagnet is made of a solenoid coil with a steel core. One of the electromagnet poles faces the top of a post on which the ball rests. The ball elevation from the top of the post is measured using a photo-sensitive sensor embedded in the post. When the ball rests on top of the post, the air gap between the top hemisphere of the ball and the electromagnet pole face is 14 mm. The post also provides repeatable initial conditions for control system performance evaluation.

The bottom section of the Magnetic Levitation device houses the system's conditioning circuitry for the light intensity position sensor. Both offset and gain potentiometers of the ball position sensor are readily available for proper calibration. A current sense resistor provides coil current measurement.

## Quanser-developed ABET-aligned Courseware Included

The Maglev system comes with Quanser-developed courseware standardized for ABET evaluation criteria. The workbook with exercises, together with quick start resources, a comprehensive User Manual, pre-designed controllers and a system model allow you to get your lab running faster, saving months of time typically required to develop lab materials.

• One degree of freedom (1 DOF) - ball levitates vertically up and down
• Electromagnet made up of a solenoid coil and steel core
• Photo-sensitive ball position sensor
• Ball position sensor can be calibrated according to lighting conditions
• Analog coil current sensor
• Easy-connect cable and connectors
• Fully compatible with MATLAB®/Simulink® and LabVIEW™
• Fully documented system models and parameters provided for MATLAB®, Simulink®, LabVIEW™ and Maple™
• Open architecture design, allowing users to design their own controller
 Device mass 3.8 kg Dimensions (H x W x L) 15.1 cm x 15.1cm x 27.6 cm Ball position sensor sensitivity 0.28 cm/V Coil inductance 412.5 mH Coil resistance 10 Ω Number of turns in the coil wire (approximate) 2450 Coil length 8.25 cm Coil steel core radius 0.8 cm Electromagnet force constant 6.53 x 10-5 N.m²/A² Current sense resistance 1 Ω Steel ball radius 1.27 cm Steel ball mass 0.068 kg Steel ball travel 1.4 cm Magnetic permeability constant 4π x 10-7 H/m

Topics included in the Quanser-developed courseware:

• Derivation of dynamic model from first-principles
• Transfer function representation
• Linearization
• Current control
• Position control
• PID
• Feed-forward
• Control parameter tuning
##### The Magnetic Levitation can be also used to teach other topics that are not included in the Quanser-developed courseware.

To set up your Magnetic Levitation workstation, you need additional components. Quanser engineers recommend:

 for MATLAB®/Simulink® users for LabVIEW™ users 1x Q2-USB data acquisition device¹ 1x VoltPAQ-X1 linear voltage amplifier 1x VoltPAQ-X1 linear voltage amplifier Quanser Rapid Control Prototyping toolkit software QUARC real-time control software and one of the following options: - 1x NI myRIO with 1x Quanser Terminal Board for NI myRIO - 1x NI CompactRIO²controller with 2x Quanser Q1-CRIO module - 1x NI M- or X-series data acquisition device³ with 1x Quanser NI Terminal Board

¹ alternatively, you can use Q8-USB, QPIDe or any equivalent NI DAQ device supported by QUARC
² NI cRIO-9074, or NI cRIO-9024 with cRIO-9113 or cRIO-9114 chassis
³ NI DAQ device must be supported by Quanser RCP toolkit. Alternatively, you can use Quanser Q2-USBQ8-USB, or QPIDe

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