2015 rm best kickoff robot design and construction tips · 2015 rm best kickoff robot design and...

2015 RM BEST Kickoff

Robot Design and Construction Tips

Scott McEwen

September 12, 2015

Overview

Engineering Design Process

Subsystems & System Integration

Communication & Documentation

Design Engineering & Math Examples

Construction Tips

Materials

Fabrication & Safety

Engineering Design Process Importance

Proven process for any design/build project

Every team is required to submit a Project Engineering Notebook that documents your process to design, build, and test your robot

Engineering Design Process Elements

1. Define the problem

2. Determine the design specifications

3. Develop numerous design alternatives

4. Choose the optimal design

5. Build and test the design

Ref: http://best.eng.auburn.edu/ -> Participants -> File Manager > Public Resources & Training > Team Resources > Engineering Topics

http://best.eng.auburn.edu/

1) Define the Problem

EVERYONE read the Rules thoroughly at www.bestinc.org

Participants -> File Manager -> 2015 Game Files

Password: D1g4it

Participants -> Resources

Inventory Consumable & Returnable Kits

Research similar problems and designs

http://www.bestinc.org/

2) Determine the Design Specs

Clear guidelines for creating viable designs:

Goals

Score lots of low point items, then score high point items

Requirements

Ability to drive through doorways with 1”x4” base

Ability to grab various game pieces

Constraints

Must fit in 24” cube and weigh <= 24 lbs

3) Develop Numerous Design Alternatives

Engineering design = creative process + content knowledge from variety of disciplines

Brainstorming

Multiple Groups of 3-4? 1+ designs/student?

Sketches, notes, logical & physical models

Scoring Tip: Brainstorming Approaches - How well organized and productive was the brainstorming approach used and documented?

4) Choose the Optimal Design

Weigh and document pros & cons of each design

Analysis of gaming strategies and design elements to achieve goals

Do we have the tools and skills to build it?

Scoring Tip: Analytical Evaluation of Design Alternatives - Use of analytical and

mathematical skills in deciding upon and implementing design alternatives

5) Build and Test the Design

Invest adequate time and specificity prior to this step

Revisit prior design steps as needed

Scoring Tip: Safety Training *and* safety practices followed & demonstrated

Scoring Tip: Support Documentation

Drawings, photos, test results, etc.

Subsystems & System Integration

Drive Platform

Maneuverability about the game field

Speed & position control

Articulated Arm and end effector (grapple)

Rotate left to right

Extend up & down

Extend in & out

Grip efficiently

Programming

Communication & Documentation Communication Best Practices

Communication mediums

Traditional

Social media

SCRUM – Daily stand-up meetings

Other

Resolving disagreements/conflicts

What works for your team?

Communication & Documentation Engineering Notebook

Document the process used to design, build, and test the robot.

Tell the story of your robot

Documentation is a critical aspect of the Engineering Process. Provides:

Crucial record of the process

Critical info between different groups

Checklist against requirements

Essential information for new people

Communication & Documentation Important Dates

Engineering Notebooks are due on Practice Day (Saturday, Oct 17 by 2pm)

Every team MUST submit a Project Engineering Notebook

Notebooks can be hard copy or soft copy

If no notebook on Practice Day, your team will NOT be able to compete on Game Day

Notebooks will be returned on Game Day

Design Engineering & Math Examples – Torque

Dimensions and torque

Small Motor http://content.vexrobotics.com/vexpro/pdf/276-1610-Release.PDF

Large Motor http://content.vexrobotics.com/docs/276-1611-Drawing-Rev1A.pdf

Inch-pound = amount of torque required to lift a 1 pound weight that is 1 inch from center of axis of rotation

Computing torque: Torque = Force * Moment Arm

Torque = Weight (pounds) * moment arm (inches)

Total torque = Sum of (weights * moment arms)

http://content.vexrobotics.com/vexpro/pdf/276-1610-Release.PDF







http://content.vexrobotics.com/docs/276-1611-Drawing-Rev1A.pdf








PVC Pipe @ 0.21 lb/ft

Grapple @ 0.5 lb

Waste Cargo Ball @ 0.4 lb


PVC: (2 ft * 0.21 lb/ft) * 1 ft = 0.42 ft-lb

Grapple: 0.5 lb * 2 ft = 1.00 ft-lb

Ball: 0.4 lb * 2 ft = 0.80 ft-lb

Combined: 0.42 + 1.0 + 0.8 = 2.22 ft-lbs

Torque = Weight (pounds) * moment arm (feet)


2.22 ft-lbs = 26.64 in-lbs

Large Motor torque = 23.53 in-lbs

“Back to the drawing board”

Design Engineering & Math Examples – Motor Specs

Futaba S3003 servo • Torque: 2.75 in-lb (44 oz-in) • Gear Type: Plastic

BEST Small Motor • Torque: 9.49 in-lb (152 oz-in)

BEST Large Motor • Torque: 23.53 in-lb (376.48 oz-in)

Design Engineering & Math Examples – Potentiometer (Pot)

Definition. A Pot is an electrical device whose resistance is adjustable. It can be used as an analog sensor to measure angular position of a rotational component, such as a robot arm. The Cortex can use the Pot’s output to control or limit some other component.

Input. Connect Pot’s shaft to a rotational axle or shaft. NOTE: the POT’s total range of motion (i.e., rotation) is 300 degrees.

Output. Connect the Pot’s wiring to a Cortex analog input port.

Operation. As the resistance of the Pot changes, so does the voltage. This varying voltage can be measured by the Cortex and is directly proportional to the angular position of the Pot’s shaft.

Data sheet: http://www.bitechnologies.com/pdfs/p160.pdf

easyC example: https://sites.google.com/site/team3141rx/easyc/arm3

Wiring example: http://www.education.rec.ri.cmu.edu/classes/cal_u/ar/toolbox/content/curriculum/robotics_systems/home_brew/potentiometer/potentiometer.swf

http://www.bitechnologies.com/pdfs/p160.pdf



https://sites.google.com/site/team3141rx/easyc/arm3

https://sites.google.com/site/team3141rx/easyc/arm3

http://www.education.rec.ri.cmu.edu/classes/cal_u/ar/toolbox/content/curriculum/robotics_systems/home_brew/potentiometer/potentiometer.swf




• Simulink

• easyCv5 for Cortex

• RobotC

• Solidworks, HSMWorks, Solidwize

• Mathematica for Students

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BEST Software Licensing Options

Download Instructions

Software Download Instructions are available on the USB memory stick in the Teacher Packet provided at Kickoff registration.

Change for 2015: RobotC requires web registration to access One Team License

License expires 12/31/15

Construction Tips

Materials


Materials

Polypropylene sheet & polycarbonate sheet

Aluminum bar, rod, & sheet

Steel all-thread rod & piano wire

Wood, plywood, 1x4, dowel & ¾” foam board insulation

PVC pipe, tees & elbows (in 3 sizes)

Hardware, Electrical, Tapes & Adhesives

Fasteners & Miscellaneous

Fabrication & Safety East High School

Location

1600 City Park Esplanade, Denver

Near Colorado Blvd & Colfax

Woodwork Shop, with CNC router

Contact:

Joel Noble, Shop Teacher

(720) 423-8560

[email protected]

Fabrication & Safety Cutting Plastic Sheet (video)

Wear eye protection & secure work

1. Scribe and break – Sturdy knife

Good for 1/8” sheet

2. Jig saw – New blade, 10 teeth/inch

3. Band saw – ½-wide blade, 14 teeth/inch

May cause melting

4. Circular saw – Carbide tip, triple-chip

Plywood blade will cause melting

5. Table saw – 60-80 teeth, triple-chip, 1/8 to ½ inch blade exposed

http://www.tapplastics.com/product_info/videos/how_to_cut_plastic_sheet

Fabrication & Safety Cutting Aluminum Bar & Rod


½-inch Bar

Hacksaw: laborious and slow

Jig saw: (see notes)

Band saw: wood-cutting blade

Horizontal band saw:

straight & safe

Fabrication & Safety Cutting Aluminum Sheet

Tin Snips: laborious

Stop short of full cut to avoid cut marks

Air or power shears

Sheet metal shear

For marking, use ultrafine Sharpie

After cutting, dress edges with file

Fabrication & Safety Bending Aluminum Sheet

• Hand bender • Vise • Sheet metal brake

Fabrication & Safety PVC and Wood

PVC

Hacksaw

PVC cutter

Wood: Holes & round parts

Drill

Drill press

Hole saw

Fabrication & Safety Drill Press Speeds (rpm)

Bit Type Plywood & Pine

Acrylic Aluminum Steel

Twist, 1/16” to 3/16” 3000 2500 3000 3000

Twist, 1/4” to 3/8” 3000 2000 2500 1000

Twist, 7/16” to 5/8” 1500 1500 1500 600

Twist, 11/16” to 1” 750 NR 1000 350

Hole Saw, 1” to 2.5” 500 NR 250 NR

Spade bit w/ spurs, 3/8” to 1” 2000 500 NR NR

Circle Cutter, 1.5” to 3” 500 250 NR NR

Circle Cutter, 3.25 to 6” 250 250 NR NR

Circle cutters: Drill 1st side, flip material over, finish on 2nd side




Center punch holes to prevent drill from wandering

Clamp work

Fabrication & Safety Fasteners – Drill and Tap

Machine Screw

Drill Bit Number

1/4”-20 8

#10-32 21

#8-32 29

• Threads are cut inside a hole using a tap

• Match hole size (numbered drill bit) to screw

• Screws: size – threads/inch • Purchase drill/tap sets at Ace

Hardware

Fabrication & Safety Foam Board

Cut with Hot knife or sharp utility knife with multiple cuts and minimal pressure against a metal ruler*.

*Read more : http://www.ehow.com/how_4558222_cut-foam-board.html

Draw cut lines before starting

Edges may crumble or shed 34

http://www.ehow.com/how_4558222_cut-foam-board.html






Fabrication & Safety Electrical Components

Proper connection of electrical components Mount Cortex for easy access

Fabrication & Safety Limit Switches

SubMini Snap

Connect to digital port: Closed = “0”; Open = “1”

Fabrication & Safety VEX Motor Mounting Kit

• Specifically designed to mount BEST motors

• Flat, but designed to be easily bent

Fabrication & Safety BEST References

http://best.eng.auburn.edu/b_game_rules.php

http://best.eng.auburn.edu/stored_procedures/folder-manager/

1. 2015 RMBEST Consumable Kit List

2. 2015 RMBEST Returnable Kit List

3. BEST Large Motor Spec Sheet

4. BEST Small Motor Spec Sheet

5. BEST Generic Kit Usage Guide

6. 4.X VEXnet Firmware Upgrade Utility Operating Instructions and Installation

7. Cortex Microcontroller and VEXnet Joystick User Guide

8. VEX Cortex Pin-out

9. Introduction to easyC & Cortex (Intelitek)

10. Google for PDF: “Tools, Tips and Materials” by David Kwast






2015 rm best kickoff robot design and construction tips · 2015 rm best kickoff robot design and...

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