The Design Process - FRC

The Design Process

Mr. Christopher BeardenPatriot Systems [email protected]: @C_Bearden321-777-2369

FRC Team 1592

Bionic Tigers

For

mailto:[email protected]



Video Presentation

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click on the following link :

The Design Process Video

http://www.patriotsec.com/index-3.html

Purpose

• Describe the engineering process used

by industry

• Relate the engineering process to the

FRC

Developing a System5 Major Phases

Analysis Design Build Test Support

• Requirements Analysis

• Strategy

• Detailed Design

• Preliminary Design

• Integration

• Fabrication

• Design Testing

• Validation

• Upgrades

• Defects

= Design Reviews

Ideas Prototypes Finished Product

What will be our execution strategy for this work?


Specialities

1. Mech Eng - Pneu, Propulsion, Fluids

2. Software Eng - Operating

Sys, Algorithm, Embedded

3. Elect Eng -

Radar, Power, Communications

4. Architects

5. Chemical Engs

6. ……..possibly many more!

Staffing

1. Who is available?

2. Do employees have the

necessary experience?

3. Should we hire someone?

4. Should we give some work

to another company?

Location of Work

1. Where will the work be performed

(U.S. Or Overseas)?

2. Do we adequate facilities at those

locations?

Tools & Equipment

1. Software – Lab View or C++

2. Engineering – Pro E or Autodesk

Inventor

3. Machine shops

4. Electronic manufacturing

Development

Process

1. Design reviews

2. Parallel activities

3. Schedule

Roles & Responsibilities

1. How are we organized to

execute the work?

2. Who is in charge of who?

3. Who is responsible for what?

Execution

Strategy(Program Plan)

Types of Requirements

Sources of

Requirements

Functional Performance Physical Interface Services

1. Customer

Specifications

2. Marketing

3. Safety

Standards

4. Meetings

5. Company Stds

6. Industry Stds

What must this product do?

How well must it perform this task?

What size,weight, color

must it be?

How will people useit? What

makes it work with other products?

Besides the product, what else

must be delivered (training,

documents,

maintenance,

etc.)?

1. Game Rules

2. Team Strategy

3. Robot Manual

4. Awards

5. Arena

6. Meetings

Same Same Same Same Same


What are we supposed to be building?

Industry

FIRST Robotics Competition


Examples of Requirements

1. Minibot must ascend a metal pole and impact a

sensor disk. (Functional)

2. …..must climb the tower < 10 seconds

(Performance)

3. Sponsors logo’s will be displayed on HostBOT

(Physical)

4. A driver station will be used to control the HostBOT

(Interface)

5. HostBOT will not cross the vertical plane of an

opponents zone (Services – Operator Training)

What are the major pieces of our robot system?


ROBOT “System”

Operator

Driver Station

Host Bot

MiniBot

Launcher

Chassis

Manipulator

MiniBot

Block Diagram

“System” implies people, equipment

and documentation

Need a design concept to

get started

What are the ALL the pieces of our robot system?


Breakdown

Diagram

Requirements Brainstorming


• Technical teams meet to define the requirements for subsystems and assemblies– Functional– Performance– Physical

– Interface

• Example1. The D/S allows an operator to control the HostBOT - Given

1a. There will be touch sensitive slider control to vary the HBOT speed from 0 to MAX – Brainstorming Session

• Assign responsibility for requirements• Software

• Mechanical

• Electrical

• Allocate requirement to the design• Which Subsystem or Assembly does this belong to?

Preliminary Design Goal: Identify and assess alternatives for each of the ROBOT subsystems (D/S, MiniBOT, etc). Choose one.


Step 1: Technical teams meet to propose solutions to the design problem.

Example: MiniBOT Design Concepts

Alternative #1: Use magnetic force to attach MBOT to the metal

tower and propel it upwards with an electric motor to impact the disk.

Alternative #2: Use a spring-loaded mechanism that clamps the

MBOT to the metal tower when the MBOT impacts the tower.

Step 2: Evaluate the alternatives.

Step 2a. Test the concepts using a mock-up or a model.


Example: Alternative #1 Mock-Up

Tape magnets to wood chassis; attach wheels; size it for the tower.

Knowing that the MBOT will need a motor, wheels, battery pack – find that

weight and add it to the mock-up – say 5lbs.

Test 1: What # and weight of magnets would it take to hold 5lbs

upright against the tower?

- How does this change as weight is added?

Test 2: How close to the tower must the magnets be?

- How does this change as distance changes?

Test 3: Do magnets affect the operation of the electric motor?

- What separation distance is needed?

Test 4: Will the MBOT travel in a straight line up the tower?

- How could this be corrected?


Step 2b: Consider the design constraints

a. Volume of MBOT is restricted to 12” x 12” x12”

b. MBOT must not weigh more than 15lbs

c. No more than 2 motors

d. Powered only by 12VDC battery

e. Allowed materials

Step 2c: What are the risks of this approach?

Ex: What if ……..the

MBOT falls off the tower

after impacting the

upper disk?

Can this risk be

mitigated somehow?


Step 3: Compare the alternatives

Alt #1 Alt #2 Alt #3

Performance 4 secs 5 secs 9 secs

Risk High Medium Low

Cost $ 100 $ 500 $100

Color Criteria:

Performance: if time <= 5 secs (Green)

>5<= 10 secs (Yellow) >10 secs (Red)

Cost: <= $100 (Green)>$100 <= $400 (Yellow)> $400 (Red)

Step 4: Select an alternative


Step 5: Add design-level requirements to the existing requirements.

Example: Add what was learned from testing the

mock-up.

Step 6: Create a Preliminary Layout Diagram

Motor

Gears

BatteryPack Magnets

Wheel

WheelWheel

Wheel

Kill

Sw

12” max

Detailed Design Goals: Identify specific parts and materials. Specify how these parts interact.


Step 1: Identify the mathematical word problems and solve them.

Example: What gear design will propel a 5 lbs MBOT up the tower

at a speed of X inches/second using an electric motor with an output

power of……..a rotational speed of ……..and 4” diameter wheels?

Step 2: Identify parts

- Consider the design constraints from the Robot Manual

- Make it or buy it?

-- Cost limits imposed by FRC ($400 per part)

-- May need a detailed drawing if “make”

- Add parts information to the “Breakdown Diagram”

- Are there any “long lead” parts?


Step 3: Design the interfaces

What SW or HW must be added to the design to make the pieces

fit and function together ?

- HOSTBOT

-- Manipulator Assy

-- Chassis Assy

-- MiniBOT Launcher Assy

-- MiniBOT Assy

Step 4: Create the drawings and digital models

- Layout Drawings

- Electrical Schematics

- Fabricated Parts

The Build Phase Goals: Have a completed Robot system (including SW) that isready for testing.


Step 1: Drawings are released to machine shop (machinists, microelect, etc).

Step 2: Purchase Requests are released (a specialist in Industry).

Step 3: Transportation requirements are defined; materials are

purchased; crates are constructed.

Step 4: Parts are received and put into kits (a box or a shelf location)

Use the Breakdown Diagram

Step 5: Kits are assembled.

Step 6: Assemblies are integrated.

Manipulator Assy Kit

Chassis AssyKit

MIniBot AssyKit

MiniBotLauncher Assy Kit

The Test Phase Goals: Test the performance limits of the product. Verify the product meets the customer’s original set of requirements .


Developmental Testing

- How fast, how high, how far?

- Determining the safety limits

- Breaking points

Validation

- Prove to the customer that the product meets or exceeds

their original requirements

- Product ships when the customer is satisfied

The Support Phase Goals: Design new features for a fielded product. Fixing defectsthat were discovered by users.


A new feature (i.e. requirement) sends you all the way back to

the Analysis Phase!

** What’s the implication here?****

Types of defects

- Software bug

- Parts that break too often

-- Environment (heat, humidity)

-- High usage

-- Poor quality

Replacement parts (or software) no longer made

How is Software different?


Process phases can be the same but different diagrams and products than HW.

SW development methods and tools very different than HW.- Object Oriented Design

- Architecture Development Languages

- AGILE development

- Service Oriented Architectures

Analysis

- SW Architecture (versus Block Diagram)

Design

- Adding more detail to SW architecture

- Designing the interfaces to HW items

- Designing screen layouts

- Data structures, algorithms and sequencing

Build

- Writing and deploying code

- Version control

- Completing the SW architecture by integrating its pieces

Waterfall Development Process

The Last Word


80% of catastrophes discovered here

But they were caused here!

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The Design Process - FRC