Team Lifted:
Critical Design
Review
Andrew Cober
Dan Crowe
Sujan Gautam
Anthony Schubert
Ryan Yeash
Overview / Revised Goals
Dan Crowe
Overview
Project
 Problems and Design Modifications
 Hardware/Schematics
 Electromagnet Construction
 Firmware/Software
 Logistics and Administration
 Questions

Project: Magnetic Control

Use electromagnets to control the position
of a magnetic object
 Control

x and y position
Control object through a user interface
 First
approach: buttons
 Second approach: touchscreen
Problems Encountered
Power limitations
 Prefabricated Electromagnets have
undesired design
 Iron core laminates disappointing
 Buck converters unable to source
sufficient current

Design Modifications
Control object on 2D surface
 Construct electromagnets powerful
enough to meet specifications
 Use ferrite cores for lower core loss
 Implement H-bridge to divert current
 Control position of a magnetic object
 Apparatus made of plexiglass

Revised Goals
Effectively control the object with 1cm
accuracy in 2-D plane
 Touchscreen sensing

 Touchscreen

interface
Object follows a user defined path
Revised Design
Four electromagnets mounted on a
platform
 Cyclone II FPGA used to control the
current to the electromagnets through Hbridge
 Control based on position of the object

 Touchscreen
Hardware/Schematics
Ryan Yeash
Hardware Block Diagram
ADC Conversion Circuit
RS232 Connection
JTAG Connection
Power Circuitry
Electromagnet Control
Electromagnet Specifics
Sujan Gautam
Electromagnets
I-Core solenoid 3.5”x1”x1”
 Ferrite core for low power loss and high
magnetic flux density
 18 AWG wire to handle sufficient current
and lower resistivity
 100-200 turns depending on field output

Some Calculations






Length  3.5”
Number of turns  100
DC current  5 A
Relative permeability 
200
B  0.5 Tesla
This does not take into
account the core and wire
loss
Firmware Specifics
Anthony Schubert
Some Altera Details

HAL
 Hardware Abstraction
Layer
 An API (Application Programming Interface)
for use with Altera’s Nios II modules
 Allows easy C programming

Parallel I/O
 General
purpose interface for peripherals
 Allows for many possible configurations
FPGA Configuration
Current Tasks

Interrupt-driven user interface
 Have
been using HAL API to write interrupt handlers
for button inputs
 Will eventually use for user input

SRAM
 Configured
Cyclone II on development board to use
off-chip SDRAM
 Would prefer to use off-chip SRAM

Smaller but faster
 Need

off chip memory to use HAL
Start processing ADC input
Controller Firmware

Proportional Controller
 Implemented
through control of
electromagnets with PWM

Derivative Controller
 Implemented
by calculating the rate at which
the object is moving

Hence PD control
Software Flow Diagram
Initialize
Hardware
Power on
Activate
Magnets
No
Start User
Input
Object
Detected?
Yes
No
User shift?
Center
Object
Yes
No
Shutdown
Sequence
Object
Shifted?
Yes
Logistics and Administration
Andrew Cober
Cost
Qt.
4
1
4
3
2
2
Part
Attained From
Iron Cores
Power Lab
Touchscreen
www.touchscreens.com
H-bridge (complete cost)
Advanced Circuits, Digikey, Mouser
FPGA PCB (complete cost)
Advanced Circuits, Digikey, Mouser
Cyclone II Dev. Board
Tom Brown
18 AWG Magnet Wire
www.bulkwire.com
Misc.
Extra Resistors, Capacitors, etc Digikey
Apparatus (complete cost)
Home Depot
Ferro-Fluid 1L
Ea.
Cost
$0.00
$0.00
$170.00
$170.00
$78.00
$312.00
$116.00
$348.00
$0.00
$0.00
$20.00
$40.00
$30.00
$60.00
$200.00
Total
$1,160.00
Spent
Left
$592.16
$1,320.84
Division of Labor
Andrew
Cober
Mechanical
PCB
Dan Crowe
Anthony
Schubert
Ryan Yeash
Sujan
Gautam
R
CI
R
R
CI
Power
Control
R
R
CI
R
System
Modeling
R
CI
R
R
Control
Algorithm
R
R
R
CI
Firmware
R
R
R
R – Responsible and CI – Consult and Inform
Everyone is informed when a task is completed or needs further
assistance
Timeline Estimate
Milestones

Completed
 CDR:
Obtained most parts, started
development of software framework, FPGA
PCB design completed
FPGA PCB Layout Rev. 1
Milestones Continued

Still to come
 M1:
Simple one dimensional control and
movement of object
 M2: Control x and y coordinates of the object
 Expo: Path control and completion of project
Questions
Extra Slides
Risks
Power limitations into the magnets may
limit object size
 Control complexity may be too difficult to
implement
 May have to rescale from FPGA to MSP

Contingency Plans

Use photo diodes rather than touchscreen
for object position control
Possible Extensions

Addition of LCD to display object data
 Touchscreen
for user control
 Trackball control
Wireless communication between
apparatus and user interface
 Implement multi-core processing on
Cyclone II

NiosII Softcore
FPGA Configuration

Cyclone II FPGA
 Nios
II softcore processor
 LCD controlled using FSM


Receives commands and data from NIOS II via parallel I/O
May switch to built-in LCD module
 Parallel
I/O for button inputs
 JTAG module for programming/debug
 SRAM/SDRAM controller