Team Lifted:Critical Design Review Andrew CoberDan CroweSujan GautamAnthony SchubertRyan Yeash

Overview / Revised GoalsDan 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 objectControl x and y position

Control object through a user interfaceFirst approach: buttonsSecond 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 sensingTouchscreen 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 H-bridge

Control based on position of the objectTouchscreen

Hardware/Schematics Ryan Yeash

Hardware Block Diagram

ADC Conversion Circuit

RS232 Connection

JTAG Connection

Power Circuitry

Electromagnet Control

Electromagnet SpecificsSujan 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 SpecificsAnthony Schubert

Some Altera Details

HAL Hardware Abstraction LayerAn API (Application Programming Interface)

for use with Altera’s Nios II modulesAllows easy C programming

Parallel I/OGeneral purpose interface for peripheralsAllows 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 DiagramPower on

Initialize Hardware

Activate Magnets

ObjectDetected?

CenterObject

Yes

No

ObjectShifted?

Yes

No

Start UserInput

User shift? Yes

No

ShutdownSequence

Logistics and Administration Andrew Cober

Cost

Qt. Part Attained From Ea. Cost4 Iron Cores Power Lab $0.00 $0.001 Touchscreen www.touchscreens.com $170.00 $170.004 H-bridge (complete cost) Advanced Circuits, Digikey, Mouser $78.00 $312.003 FPGA PCB (complete cost) Advanced Circuits, Digikey, Mouser $116.00 $348.002 Cyclone II Dev. Board Tom Brown $0.00 $0.002 18 AWG Magnet Wire www.bulkwire.com $20.00 $40.00

Misc.Extra Resistors, Capacitors, etc Digikey $30.00Apparatus (complete cost) Home Depot $60.00Ferro-Fluid 1L $200.00

Total $1,160.00

Spent $592.16Left $1,320.84

Division of LaborAndrew Cober

Dan CroweAnthony Schubert

Ryan YeashSujan

Gautam

Mechanical R CI R R

PCB CI R

Power Control

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

CompletedCDR: Obtained most parts, started

development of software framework, FPGA PCB design completed

FPGA PCB Layout Rev. 1

Milestones Continued

Still to comeM1: Simple one dimensional control and

movement of object M2: Control x and y coordinates of the objectExpo: 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 dataTouchscreen for user controlTrackball 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