ROCHESTER INSTITUTE OF TECHNOLOGY

P11217: GOLF ROBOT Detailed Design Review

Senior Design I

Meeting Purpose:

1. Overview of the project

2. Review/Improve design

3. Address any severe risks

4. Review BOM

5. Prepare to build prototype

6. Receive feedback from customer and faculty advisors

Materials to be reviewed:

1. System architecture(subsystems)

2. Navigation system

3. Software algorithms

4. Feasibility analysis

5. Circuit schematics

6. Updated Risk Assessment

7. Updated Bill of Material

Meeting Date: February 11, 2011

Meeting Location: 70-1455

Meeting time: 3:00-5:00pm

Timeline:

Meeting Timeline

Start

time Topic of Review Required Attendees

3:00 pm System architecture

3:20pm Review navigation systems

3:30 pm Software algorithms

3:45 pm Feasibility analysis

3:55 pm Circuit schematics

4:10 pm Updated risk assessment

4:25 pm Updated BOM

4:40 pm Feedback/ Question and Answer Period

PROJECT DESCRIPTION

PROJECT BACKGROUND: The Virtual Golf Project is a collaborative effort

between Facilities Management personnel and RIT

Academics. This project is led by David Schwartz

and Jessica Bayliss in the Department of Interactive

Games and Media, and is meant to be a mainstay at

the 2010 Imagine RIT Exposition.

The project has participants hitting golf balls at

an augmented reality tee-off which shows the

simulated flight and landing of a ball at the green. A

robot will then deliver a ball to the corresponding

location on a real green, where the player will be able

to putt.

PROBLEM STATEMENT: The robot requested must be able to deliver a

golf ball to a given set of target coordinates on golf

green. Equipment may not be permanently stationed

on the green itself and interference with the

surrounding area should be kept at a minimum in

order to make access to the green easier.

OBJECTIVES/SCOPE:

The robot must be able to wirelessly

communicate with a PC at a distance of at least

100 feet for the purposes of receiving target

coordinates and sending a 'task completed' signal

during each round

The robot should navigate to the received

coordinates with a margin of error less than 2

inches near the center of the hole

Carry and drop a golf ball at the target

coordinates.

DELIVERABLES: The robot requested must be able to deliver a

golf ball to a given set of target coordinates on a golf

green. Equipment may not be permanently stationed

on the green itself, and interference with the

surrounding area should be kept at a minimum in

order to make access to the green easier.

In order to complete these objectives, the robot must

be able to:

Wirelessly communicate with a PC at a distance

of at least 100 feet for the purposes of receiving

target coordinates and sending a ‘task

completed’ signal during each round.

Navigate to the received coordinates with a

margin of error less than two feet

Move freely across a golf green (flat, short grass,

~30ft diameter)

Carry and drop a golf ball at the target

coordinates

The robot must complete its task within a

reasonable time, and without causing visible

damage to the green itself. The robot is expected

to work for approximately 8 hours straight, with

opportunities to change out the power source

between deliveries

EXPECTED PROJECT BENEFITS: We expect the Department of Interactive Games

and Media to gain a reliable and entertaining

add-on component for their AR Golf product

We expect AR Golf players to have a memorable

experience interacting with the Golf Robot at this

year's Imagine RIT festival

We expect the robot team to gain valuable

experience in system engineering which

complements their education and will be applied

in future employment

TEAM MEMBERS: Cory Gregory – Project Manager

John Gutmann – Lead Engineer

Derek Hugo – Secretary

Karikalan Thirumavalavan – Customer Needs

Representative

Jason Thrush – Software Representative

Marcus Grant – Electrical Engineer

Jeff Cosimano – Mechanical Engineer

Tenzin Seldon – Mechanical Engineer

STRATEGY & APPROACH

ASSUMPTIONS & CONSTRAINTS: An operator/attendant will be available to

perform basic maintenance, cleaning, and battery

replacement. He/She will also be able to answer

basic questions from players about the robot.

The golf green will resemble a typical golf

green: flat or gentle slope, clear of obstacles, dry,

short grass, solid soil and a single hole.

The golf simulator operators will have roughly

an hour of setup/teardown time to prepare &

calibrate robot and support equipment.

A power outlet or extension cord will be

available for the laptop, router, and other beacon

equipment.

While we plan to make the robot resistant to

moisture, the robot may become inoperative in

heavy rain or other severe weather.

UPDATED CUSTOMER NEEDS

Customer Need #

Importance Description Comments/Status

CN1 1 Robot must deliver golf ball to a

given set of coordinates on golf

green.

CN2 1 Robot must complete task without

interrupting the flow of the game.

CN3 2 Minimal movement of the ball after

placement.

CN4 1 Robot should move freely across a

reasonable sized golf green.

CN5 1 Robot should travel to given

coordinates within an unnoticeable

margin of error.

CN6 1 Robot must communicate with the

simulator.

CN7 1 Robot may not obstruct path of the

ball to the hole.

CN8 1 Robot may not obstruct user access

of the ball.

CN9 1 Robot must complete task without

causing visible damage to the golf

green.

CN10 2 Robot must stop if anything comes

within close proximity.

CN11 2 Robot must be durable and function

outdoors in varying weather.

CN12 2 Robot needs to be portable.

CN13 1 Robot battery should be able to be

swapped out without interrupting

the flow of the game.

CN14 1 Robot should operate for a

reasonable amount of time.

CN15 1 Users, operators and spectators

should be able to harmlessly

interact with robot.

CN16 2 Robot must cease operation while

the user is putting and resume after.

CN17 2 Robot must be user friendly and

intuitive.

CN18 3 Robot should interact with the user

for a pleasurable experience.

UPDATED ENGINEERING SPECS

Eng.

Spec. #

Importance Source Specification Unit of

Measure Marginal

Value Ideal Value

Comments /Status

ES1 1 CN2 Robot speed Ball

deliveries

/ hour

10 >10

ES2 1 CN1,

CN3

Ball must be within

radius of coordinates

in 2 <2

ES3 1 CN4 Distance robot should

move

Ft 30 <30

ES4 1 CN5 Navigational margin

of error

% 0.40 <0.40

ES5 1 CN6 Wireless

communication range

Ft 40 >40

ES6 1 CN9 Smooth treads on

wheels

N/A N/A N/A

ES7 2 CN11 Solid outer shell N/A N/A N/A Water

Resistant

ES8 2 CN11 Clearance from

ground

In 2 >2

ES9 2 CN12 Weight of robot Lbs 50 <50

ES10 1 CN13,

CN14

Battery life Hrs 1 >1

ES11 1 CN7,

CN8,

CN10,

CN15

Distance kept from

user

Ft 1 >1

ES12 2 CN16 Sensor to detect ball

returned to robot

N/A N/A N/A

ES13 3 CN17,

CN18

Have funnel for ball

insertion by golfer

N/A N/A N/A

Concept Selection – Golf Robot Mobility (Chosen Concept: Four Wheels)

Four wheels Omni-wheels Treads Legs

Maneuverability + + D +

Physical Impact + + A +

Speed S S T -

Cost + - U -

Power S S M -

Accuracy S + -

Simplicity + - -

Sum +'s 4 3 - 2

Sum S's 3 2 - 0

Sum -'s 0 2 - 5

Navigation Methods (Chosen Concept: Ultrasonic)

Camera GPS Line-following Ultra-Sonic

Accuracy + D + +

Precision - A + +

Setup Simplicity - T - +

Cost S U - S

Feasibility - M + +

Software Simplicity S + S

Time Length S - +

Sum +'s 1 - 4 5

Sum S's 3 - 0 2

Sum -'s 3 - 3 0

Communication Methods (Chosen Concept: Laptop Relay)

Laptop Relay

WiFi RF Laptop - Dock Relay Wired Zigbee

Range + + D + + -

Cost S + A - + +

Feasibility + + T - - +

Simplicity S - U + + +

Reliability S S M + + +

Sum +'s 2 3 - 3 4 4

Sum S's 3 1 - 0 0 0

Sum -'s 0 1 - 2 1 1

Ball Placement (Chosen Concept: Funnel)

Funnel Arm Vacuum

Cost + D -

Feasibility + A -

Simplicity + T -

Accuracy S U S

Power + M -

Sum +'s 4 - 0

Sum S's 1 - 1

Sum -'s 0 - 4

Robot Platform/Chassis (Chosen Concept: Vex)

iRobot Create VEX Lynxmotion Custom Design

Cost - + D S

Extendability - + A +

Ruggedness - S T S

Reliability S S U -

Simpilicity + S M -

Sum +'s 1 2 - 1

Sum S's 1 3 - 2

Sum -'s 3 0 - 2

SYSTEM ARCHITECTURE

Level 0

Level 1

Level 2

NAVIGATION METHOD: ULTRASONIC

The robot will position itself on the green with the help of two ultrasonic beacons placed on the

outside of the green. Each beacon will emit and receive on different frequencies. The robot will

emit a quick ultrasonic burst at one of the beacon's frequencies. The robot will then start a timer.

When the beacon hears this burst from the robot, it will send back another ultrasonic burst at

another frequency. When the robot hears this burst back, it will stop its timer. The measured time

represents the time-of-flight time of the burst, or its round-trip-time.

The robot can then calculate its distance from that beacon, by knowing the speed of sound. This

process is repeated again for the other beacon so that the robots distance from it is also known.

From then, trigonometry can be used to find the robots’ (x, y) coordinates on the golf green.

Calculations:

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FEASABILITY ANALYSIS

Camera Tracking Error Analysis:

Operating Conditions:

Component Resolution:

Coordinate Equations:

X-component:

Y-component: Because of the large range of angles needed, and the use of trigonometric functions, the navigation system diverges at certain points creating improper heading readings.

Motor Analysis: Assumed Specs:

Conversions:

Gearbox Selection:

Banebots.com has two adequate gearboxes, one has a ratio of 20:1, the other has one of 25:1 depending on the factor of safety desired.

Beacon Trilateration Error Analysis

(

) √

Speed of sound chosen at aprox. 30®C and travel time calculated at 32 ft.

√

√

(

) (

)

√ (

)

√

√

√

√

Four points are chosen on the outskirts of the green to determine max./min. errors.

√

√

√

√

√

√

√

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CIRCUIT SCHEMATIC

ELECTRICAL DIAGRAM

BEACON

ROBOT

BALL PLACEMENT MECHANISM

CAD DRAWINGS

Side View

Top View

CIRCUIT SCHEMATIC OF THE BALL PLACEMENT

AR GOLF COMMUNICATION

The robot will communicate with the AR Golf software via a laptop relay. The laptop will be

stationed by the golf green and will hold the queue of players. The laptop software will query the

AR Golf software via an HTTP request to get the list of players, as well as the corresponding

coordinates of where the ball should be placed on the green during their turn. For each player's

turn, the laptop software will send that player's corresponding coordinates to the robot so that it

can place the ball there.

The software also allows the operator to add and remove players, as well as bump players up and

down the queue, as needed.

Note: The currently pictured software is very early in development and may change.

RISK ASSESSMENT

L - Likelihood Scale:

1 - This cause is unlikely to happen

2 - This cause could conceivably happen

3 - This cause is very likely to happen

S - Severity Scale:

1

-

The impact on the project is very minor. We will still meet deliverables on time and within

budget, but it will cause extra work

2

-

The impact on the project is noticeable. We will deliver reduced functionality, go over budget,

or fail to meet some of our Engineering Specifications.

3

-

The impact on the project is severe. We will not be able to deliver, or what we deliver will not

meet the customer's needs.

I - Importance Score = (Likelihood x Severity)

ID

Risk Item

Effect Cause L S I

Action to Minimize Risk

Owner

1 Too much

signal

interference

Wireless

receiver

getting mixed

signals

Used proprietary

carrier wave

1 3 3 Use close range

wireless for

strong signal

strength and

use of non-

proprietary

carrier wave.

EE

2 Out of range Receiver

unable to

receive

coordinates

Robot has poor

navigation, or

does not return to

the home position

correctly, based

on design

2 3 6 Have a range of

coordinates in

the program for

where the robot

is allowed to go

and not allowed

to go

CE

3 Reference

coordinates

misunderstood

Robot places

ball in

incorrect

position

Poor interfacing

between game

design team and

robot team, or

robot has lost data

in coordinate

transmission

1 3 3 Design an

interface

protocol with

game design

group

CE

4 Motor is too

weak

Wheels do

not move

Poor motor

selection, motor

signal too low, or

mechanism seized

1 3 3 Do calculations

beforehand to

be sure motor

will be

powerful

enough

ME

5 Wheel slippage Robot places

ball in

incorrect

position

Wheels do not

have enough grip

for the terrain or

conditions, could

be poor wheel

selection

2 3 6 Pick wheels

which are

unlikely to slip

or have a

mechanism to

sense when the

wheels are

slipping

ME

6 Too slow Robot takes

more than

allotted time

to place ball

Poor motor

selection,

navigation

algorithm is not

steam-lined or

poor navigation

method

2 2 4 Do calculations

beforehand to

be sure motor

will be

powerful

enough

ME

7 Faulty

reading/no

reading from

sensors

Encoders,

battery life

indicator,

digital

compass fail

to provide

accurate data

Sensors have low

level of accuracy,

bad ground points,

or weak power

2 3 6 Make sure all

sensors are

working during

developemnt

EE

8 Circuit

breaker/fuses

are consistently

tripped

Robot stops

operation

Too much current

being drawn

1 3 3 Do calculations

beforehand to

be sure motor

will be

powerful

enough

EE

9 Battery fails Battery

smokes

Too much current

being drawn

1 3 3 Use circuit

breakers

EE

10 Power supply

runs out

Robot stops

operation

Battery dies 1 3 3 Create battery

level detector

EE

11 Short circuit Robot

performs

incorrectly

Multiple nodes

make contact

1 3 3 Shrink wrap

open wire

EE

12 Reverse voltage Robot

performs

incorrectly

Battery connected

backwards

1 3 3 Polarized

connectors

EE

13 Loose

connection

Robot stops

operation

Wire comes out of

place

2 2 4 Make solid

connections

EE

14 Interference

from

metal/magnets

Digital

compass

gives faulty

reading

Poor mounting of

sensor or robot

components

impede or

interfere with

sensor

3 3 9 Place compass

in a location

where it will

not be

interfered with

EE

15 Robot senses

non-existent ball

Robot begins

a journey

with no ball

Ball sensor

malfunctions or

gets stuck

1 2 2 Use reliable

sensor and

block ball

passageway

when not in use

CE

16 Robot sees non-

existent obstacle

Robot stops

in the middle

of its path

Obstacle sensor

poorly mounted

1 3 3 Mount sensor

so that

interference

cone is not

intersecting the

plane of travel

EE

17 Ball stuck in

robot

Ball cannot

be placed

Ball canal was

designed poorly or

debris was

allowed

2 3 6 Design ball

system so that

nothing can get

into the ball

shoot, except

the ball

ME

18 Phototransistor

doesn't

recognize ball

Robot would

remain idle

Sensors are placed

too high,

reflectiveness

1 3 3 Create effective

design,

decrease LED

brightness

EE

19 Phototransistor

doesn't sense

emitter

Robot thinks

golf ball is

there

Phototransistor

and emitter not

placed in linear

fashion

1 3 3 Test ball-

placement

mechanism

beforehand

EE

20 Robot senses

incorrect

location

Non-linear

positioning

Beacons are

placed too close

together

1 3 3 Place beacons

at a far enough

location

EE

21 Beacon

frequencies are

too similar

Circuit

incorrectly

senses

reflection

Frequencies were

incorrectly

selected

2 3 6 Calculate

proper

frequencies

CE/EE

22 Robot does not

detect position

Beacon

receiver

doesn't

receive

proper signal

Signal is not

amplified enough,

beacons are too

far away

2 3 6 Place beacons

at a close

enough location

EE

23 Object

avoidance

sensors don't

Robot

collides with

object

Objects are within

range of sensors

2 2 4 Set range

correctly

EE

recognize

objects

24 Beacon is

positioned

incorrectly

Robot

calculates

incorrect

location

Beacon was

placed in incorrect

location

2 3 6 Correctly

measure fixed

location of

beacons

EE

25 Electrical

hardware failure

Robot does

not work

Manufacturing

defect, hardware

design flaw, over-

current

1 3 3 Have backups

of hardware

EE

26 Gearbox binds

up

Gearbox

breaks

Too much force

applied to gearbox

1 3 3 Do calculations

beforehand to

be sure motor

will be

powerful

enough

EE/ME

27 Weight

increases

Robot

operates

slowly or not

at all

Object placed on

top of robot

1 2 2 Check if motor

is running but

encoders aren't

ME

28 Not sealed

properly and it

rains

Circuitry is

shorted

Robot casing is

not sealed

properly

1 2 2 Perform air test

to see if there

are any holes

ME

29 Robot is kicked Robot casing

cracks/breaks

Bystander doesn't

see robot

1 1 1 Do not allow

bystanders to

step on green

ME

30 Ball drop

mechanism gets

jammed

Ball doesn't

get placed

Ball-placement

mechanism

assembled

incorrectly

1 3 3 Test ball-

placement

mechanism

beforehand

EE/ME

BILL OF MATERIALS

Sub-System

Part # Part Unit Cost Quantity Total Cost

Distributor

Drive

System

M5-RS550-12 RS550 Motors $6.53 5 $32.65 Banebots

P60K-55-0004 Gearboxes $54.50 4 $218.00 Banebots

T80P-493BG-KS4 Wheels $6.80 4 $27.20 Banebots

6435K14 Shaft collar $1.79 8 $14.32 McMaster

Chassis 275-1035 35x35 Chassis

Kit

$33.95 1 $33.95 Vex

276-2232 Booster Kit $179.99 1 $179.99 Vex

Power am-0009 Battery Cable $15.00 3 $45.00 Andy Mark

am-0282 120A Breaker $29.00 1 $29.00 Andy Mark

N/A Bussman Fuse

Panel

$10.00 1 $10.00 Autozone

am-0795 2 x 18 Ahr

SLA Batteries

$83.00 1 $83.00 Autozone

Electronics WRL-08665 XBEE Wireless

Module

$22.95 2 $45.90 Sparkfun

DEV-09949 Microcontroller $64.95 1 $64.95 Sparkfun

VICTOR-884-

12/12

Motor

Controller

$89.99 2 $179.98

IFI

Robotics

276-2156 Encoders (2-

Pack)

$19.99 1 $19.99 Vex

SEN-07915 Digital

Compass

$34.95 1 $34.95

Sparkfun

Ball

Dropper

276-2162 3-Wire Servo $19.99 1 $19.99 Vex

276-142

IR Emitter and

Detector

$3.49 1 $3.49 Radio

Shack

N/A 5' PVC Pipe $20.00 1 $20.00 Home

Depot N/A U-Bolts $1.50 2 $3.00 Home

Depot

Beacons XDR-24 24kHz

Ultrasonic

Tranducers

$1.25 6 $7.50 All

Electronics

LM567 Tone Detector

IC

$0.90 4 $3.60 All

Electronics

NE556 Dual Timer IC $0.45 2 $0.90 All

Electronics

INA126PA Instrumentation

Amplifier IC

$2.80 3 $8.40 Digikey

N/A Various

Resistors,

Capacitors, Etc

- - $10.00 Digikey

PVC044000200 Charlotte 4" x

2' PVC Pipe

$6.31 2 $12.62 Home

Depot 3P16 NDS 4" x 4"

PVC Adapter

$4.94 1 $4.94 Home

Depot 447-040HC

Mueller

Streamline 4"

PVC Slip Cap

$7.35 3 $22.05 Home

Depot