P11204 - WOCCS: Wireless Components Housing Package

Senior Design Project Data Sheet

P11204 - WOCCS: Wireless Components Housing Package

Detailed Design Review Agenda

Date: November 5, 2010

Time: 10:00am – 12:00pm

Location: Building 9 (KGCOE) Room 4435

Purpose:

1. Brief recap of systems level information and project background

2. Discuss selected concept in detail

3. Analyze selected concept

4. Discuss feasibility and functionality

5. Discuss BOMs

6. Identify suppliers/vendors

7. Develop test plan

8. Identify new risks associated with final design

Included Documentation:

1. Project Overview

2. Customer Needs and Engineering Requirements

3. Review Preliminary Concept

4. Detailed design

5. Analysis Justification

6. Analysis Results

7. Test Plan

8. Bill Of Materials

9. Design Considerations

10. Updated Risk Assessment

11. Project Plan: Status Update


Project Description

Project Background: The Wireless Command and Control family of projects

is focused on developing a student designed wireless

transmitter and receiver to be used as a wireless

solution for both students and extracurricular project

usage. This project (P11204) is a continuation of the

LV1 WOCCS Project (P11205), in which an MSD

team purchased off the shelf components to

wirelessly control the LV1-Land Vehicle Project. This

iteration of the project will design and build its own RF

Modules and transceivers and incorporate them into

one, robust and modular package.

Problem Statement:

This team (P11204) will develop a common housing

for the WOCCS system modules that protects them

from the environment, provides adequate cooling,

accommodates the I/O and provides the power.

Objectives/Scope: 1. Design a modular housing to contain and protect

all RF modules. 2. Allocate space and mounting constraints for

deliverables from the 3 RF teams and power supply team.

3. Develop means by which package can be fixed to LV-1, while making considerations for other mounting applications.

4. Maintain focus during design process on manufacturing and modularity.

Deliverables:

1. Robust layout that lends itself to modularity and ease of use

2. Design which protects modules from thermal, shock, vibration, and moisture damage

3. Fully functioning prototype

Expected Project Benefits: This project will benefit future MSD teams that

have immediate need of a robust wireless control system to work in conjunction with their individual design project. Also, this end product will benefit new students to RIT by being used as a learning tool in the classroom and for entry level design projects and competitions.

Core Team Members: Steven Rois (ME) – Project Manager

Amy Powell (IE) – Interface Manager Nate Dewey (ME)

Dustin Falkner (IE)

Strategy & Approach

Assumptions & Constraints: 1. The design and construction must comply with

Federal Communications Commission (FCC) Part 15

regulations. This is a common testing standard for

unlicensed transmission devices.

2. The design must be modular and cannot be

purchased as one unit. The use of commercially off-

the-shelf components is permitted, however.

3. The overall size and volume, including the antenna,

must comply with the space available in the housing

provided by the WCHP Module.

4. The team must provide and document all sources

used in the development of the module.

5. The team is limited to a specific budget provided by

the sponsor, Harris Corporation. An amount of $5000

per academic quarter is split between the WOCCS

family projects. The team will receive a fraction of this

amount, and must not exceed their limit; all expenses

must be documented.

Project # Project Name Project Track Project Family

P11204 Wireless Components Housing Package

Systems and Controls WOCCS

Start Term Team Guide Project Sponsor Doc. Revision

2010-1 Philip Bryan Harris Corporation ~


Customer Needs / Engineering Specifications

Needs N# Specs N# Metric Marginal Ideal

easy to move around 1 lightweight 1 kgs 7 2

inexpensive 2 small volume 1 cm 3̂ 12x14x8 11x12x6

modular design 3 removable RF modules 3 Yes Yes

interface with application 4 removable battery pack 3 Yes Yes

protect internal components 5 removable power electronics 3 No Yes

operate in various environments 6 externally accessible I/O 4 Yes Yes

robust design 7 attach/remove easily 4 time(min) 5 2

meets legal requirements 8 mounting bolts yield shear force 4 KN 20 30

shock forces 5 Gs per 6ms 10 20

puncture resistance 5 RH 25 50

vibration resistant 5 Gs 2 4

operating temp range 6 C -18 - 38 -40 - 71

moisture content 6 %RH 75 50

operational life cycle 7 cycles 100000 1000000

meets FCC regs 8 Yes Yes

FCC labeled 8 Yes Yes

number of vendors for parts 2 # 7 2

custom parts 2 % 50 25


Preliminary Design Concept

Temperature Management

Vents: Keeps the internal components at a reasonable temperature.

Vibration Management

Tight fit rails: Keeps components from moving around inside enclosure.

Puncture Management

Contoured Surface: Helps deflect possible penetrators.

Application Interface

Bolts: Simple and strong attachment method. Size/Weight: Lightweight and compact design allow unit to interface without hindering application performance.

Removes Easily Bolts: Standard and common fasteners make assembly/disassembly easier and faster

Component Organization

Slots: Separate and securely hold PBCs during usage.

Component Access

Top and side removes: Easy access to all components inside of the housing.


I/O Connector Placement:

Specifications used to lay out I/O End Plate configuration

1. USB Connector

2. Co-Axial Antenna Connector

3. LED Bank


Solid Modeling Analysis Justification

Simple models were used to compare hand calculation values to results obtained from solid modeling

analysis in order to determine reliability and accuracy of software results

Structural Justification:

Figure 4: SolidWorks analysis of cantilevered beam deflection

Material: 6063-T6 Aluminum

Square cross sectional area E = 68.9 GPa b = h = 50 mm l = 500 mm w = 40 kN/m

Hand Calculations:


Thermal Justification:

Figure 5: SolidWorks analysis of Thermal conduction

Material: 6063-T6 Aluminum

k = 209 W/m-K h = 500 W/m2-K T1 = 25 C = 298.15 K T2 = 70 C = 343.15 K t = 100 mm A = 1 m2

Hand Calculations:


Analysis Results:

6063-T3 Aluminum Structural Analysis

Property Value Unit

Force Applied 27000 Applied to

bottom/top/IO

plate separately

Elastic Modulus 69 GPa

Fixed Surface Mounting Flanges

Poissons Ratio 0.33

Results

Shear Modulus 25.8 GPa IO Plate

Max Displacement

0.976 mm

Density 2700 kg/m 3̂

Max Stress 848.2 MPa

Tensile Strength 240 MPa Side

Max

Displacement 2.078 mm

Yield Strength 215 MPa

Max Stress 680.7 MPa

Thermal Conductivity

209 W/(m*K)

Cover Plate Max

Displacement 5.054 mm

Specific Heat 900 J/(kg*K)

Thermal Analysis Acrylonitrile Butadiene Styrene (ABS)

Battery Temp 40 C

Property Value Unit

Internal Air Temp 35 C

Elastic Modulus 2 GPa

Internal Convection 5 W/(m 2̂*K)

Poissons Ratio 0.394

External Air Temp 25 C

Shear Modulus 318.9 MPa

External Convection 10 W/(m 2̂*K)

Density 1020 kg/m 3̂

Results Tensile Strength 30 MPa

See Figures 14 and 15

Thermal Conductivity

0.2256 W/(m*K)

Specific Heat 1386 J/(kg*K) Mass Analysis

Mass of Enclosure 544.33 grams


Maximum Bolt Shear Based on Bolt Size

Major Diameter (mm)

Major Diameter Area (mm^2)

Minor Diameter Area (mm^2)

Maximum Yield

Force on Single Bolt (N)

Maximum Yield

Force for Our Application (N)

1.6 2.0096 n/a 679.4899712 2717.959885

2 3.14 n/a 1061.70308 4246.81232

2.5 4.90625 n/a 1658.911063 6635.64425

3 7.065 n/a 2388.83193 9555.32772

3.2 8.0384 n/a 2717.959885 10871.83954

4 12.56 n/a 4246.81232 16987.24928

5 19.625 n/a 6635.64425 26542.577

6 28.26 n/a 9555.32772 38221.31088

8 50.24 36 12172.392 48689.568

10 78.5 56.3 19036.2686 76145.0744

12 113.04 86 29078.492 116313.968

14 153.86 116 39222.152 156888.608

16 200.96 157 53085.154 212340.616

20 314 259 87573.598 350294.392

Steel Bolt Material Properties Property Value Unit

Shear Yield

Strength 586 MPa


Load Application: I/O End Plate

6. Displacement under applied load (isometric)

7. Von Mises Stress under applied load (Section View)


Load Application: Side Extrusion

8. Displacement under applied load (Section View)

9. Von Mises Stress under applied load (isometric)

10. Von Mises Stress Concentration (Detail View)


Load Application: Cover Plate

11. Displacement under applied load (Section View)

12. Displacement under applied load (isometric)


Thermal Analysis:

13. Thermal analysis (Section View)

14. Thermal analysis (isometric)


Test Plan:

Test Description Test

Number Method of Testing Pass Requirement

Pertaining Engineering

Spec

Pertaining Customer

Need

Housing Volume T1 Caliper 12cmx14cmx8cm S2 N1

Housing Mass T2 Scale 7kgs S1 N1

Assembly Time T3 Average Time (minutes) 5 mins S7 N4

Configuration Time T4 Average Time (minutes) 5 mins S7 N4

Hardness Test T5 Rockwell Hardness Test RH 25 S10 N5

Vibration Test T6 Shaker Plate 2 Gs vibes, 10 Gs Shock S11 N5

Temperature

Surface Temperature T7 Thermocouple on surface 60 C S12 N6

Internal Temperature T8 Thermocouple 60 C S12 N6


Bill of Materials

Team Part

# Description Vendor Vendor Part #

Unit Cost

QTY Total Cost

P11204 - Housing Team

1 Cover Plate Brinkman Lab 42.80 8 $342.40

2 I/O End Plate www.enclosuresandcases.com 300F

29.34

8

$234.72 3 Extrusion 300F 16

4 Base Plate 300F 8

5 Mounting

Screws 300F 12

6 M5 x 1.5mm www.mcmaster.com 92005A326 5.00/100 32 $1.60

Total $578.72

Note: Brinkman machining costs were based on estimates of material cost per cubic inch and labor costs.

Cost per volume $4 per 1 in^3 Calculated volume 3.20 in^3

Labor/Run Time $30 per hour Approximate Run

Time 8 hours

http://www.enclosuresandcases.com/

http://www.mcmaster.com/

http://www.mcmaster.com/itm/find.ASP?tab=find&context=psrchDtlLink&fasttrack=False&searchstring=92005A326


Design Considerations:

Cost Reduction:

Cover Design:

Compare price for rapid prototype to 2 piece machined and fabricated design

Tolerances:

Potential for clearance issues due to tolerance stack up

Convey minimum or maximum dimensions to vendor to ensure structural functionality

Usage Study:

Analyze ease of use by third party

Test configuration and assembly time

Test ergonomics and design intuition


P11204 MSD Project Risk Assessment Template

ID Risk Item Cause Likelihood Severity Importance Action to Minimize Risk

1 Unit Overheats Poor air circulation 1 3 3

- Components too compact 2 2 4 Keep close contact with integration team

2 Internal components

damaged Supports are inflexible 1 2 2 Use supports with high deflection and energy absorption

- CB’s are unsecured 1 3 3 All internal components independently secured to inside of housing

- Housing is punctured 1 3 3 Housing must be puncture resistant in material selection

and design

3 Board short circuits Moisture inside housing 1 3 3 Layout is designed to reduce moisture collection or

retention

- Boards contact each other 1 3 3 Secure boards separately within module

4 Difficult to remove Attachment method is too

perminent 2 2 4 Module must be removed from any user quickly and with

minimal effort

- Fixture method inaccessible 1 3 3 Place attachment hardware on outside of unit, avoid covers and locking components

5 Doesn’t attach to user Attachment hardware is

uncommon 1 2 2 Use mechanical attachments that are flexible to multiple

configurations

- Module is too heavy for user 2 3 6 Module will be under 15 pounds

- Module is too large for user 2 3 6 Keep unit under 100 in^3

6 I/O does not match users Lack of communication

between concurrent teams 1 3 3 Keep up to date schedule on all interfaces and who is

involved/responsible for those interfaces

- Interface hardware is

uncommon 1 3 3 Select I/O based on other group needs/specs to ensure

congruence

7 Control boards are difficult to remove

Poor internal layout 2 2 4 Group components that need to be interchanged separately from permanent components


- Too many permanent

connections 2 2 4 Use as few screws/bolts as possible, unit should be

disassembled in under 5 mins

8

Control boards don’t

fit in housing Housing is too small 1 3 3 Maintain constant interaction with interface group

9 Project Over Budget Too many custom parts 2 2 4 Utilize off-the-shelf components wherever possible

10 Parts come in late Vendor backorder 3 3 9

Establish secondary vendors, purchase components

ahead of est. lead time

11 Housing Components

don’t fit correctly

Tolerance stack up 2 3 6 Clearly define + or - tolerances for each component,

and make sure the vendor can meet those tolerances.

Likelihood scale Severity scale

1 - This cause is unlikely to happen 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 - This cause could conceivably happen 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 - This cause is very likely to happen 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.

P11204 - WOCCS: Wireless Components Housing Package

Documents

Transcript of P11204 - WOCCS: Wireless Components Housing Package