Upload
swann
View
33
Download
1
Tags:
Embed Size (px)
DESCRIPTION
Robot Design and Construction Tips. Scott McEwen. Overview. Engineering Design Process Subsystems & System Integration Communication & Documentation Design Engineering & Math Examples Construction Tips Materials Fabrication & Safety. Engineering Design Process Importance. - PowerPoint PPT Presentation
Citation preview
2013 Kickoff
Robot Design and Construction Tips
Scott McEwen
September 14, 2013
Overview
Engineering Design Process Subsystems & System Integration Communication & Documentation Design Engineering & Math Examples Construction Tips
Materials Fabrication & Safety
Page 2September 14, 2013
Engineering Design ProcessImportance
Proven process for any design/build project
Every team is required to submit an engineering notebook that documents the process to design, build, and test your robot
Page 3September 14, 2013
Engineering Design ProcessElements
1. Define the problem2. Determine the design
specifications3. Develop numerous design
alternatives4. Choose the optimal design5. Build and test the designRef: http://best.eng.auburn.edu/ -> Participants -> File Manager > Public Resources & Training > Team Resources > Engineering Topics
Page 4September 14, 2013
1) Define the Problem
Read the Rules thoroughly at www.bestinc.org The Competition -> 2013 Game Info Participants -> File Manager Participants -> Resources Password: WeM8keCpu$ Inventory Consumable & Returnable Kits
Research similar problems and designs
Page 5September 14, 2013
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 ascend/descend quickly Ability to grab various game pieces
Constraints Must fit in 24” cube and weigh <= 24
lbsPage 6September 14, 2013
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?
Page 7September 14, 2013
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
Page 8September 14, 2013
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 Scoring Tip: Support Documentation
Drawings, photos, test results, etc.
Page 9September 14, 2013
Subsystems & System Integration
Drive Platform Ascend & descend Speed & position control
Articulated Arm and end effector (grapple) Rotate left to right Extend up & down Extend in & out Grip efficiently
ProgrammingPage 10September 14, 2013
Communication & Documentation
Communication Best Practices
Communication mediums Traditional Social media SCRUM – Daily stand-up meetings Other
Resolving disagreements/conflicts What works for your team?
Page 11September 14, 2013
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
Page 12September 14, 2013
Communication & DocumentationImportant Dates
Engineering Notebooks are due on Practice Day (Saturday, Oct 19)
Every team MUST submit a Project Engineering Notebook
If no notebook on Practice Day, your team will NOT be able to compete on Game Day
Notebooks will be returned on Game Day
Page 13September 14, 2013
Design Engineering & MathExamples – Torque
Dimensions and torque Small Motor
http://content.vexrobotics.com/docs/276-1610-Drawing-Rev1A.pdf
Large Motor http://content.vexrobotics.com/docs/276-1611-Drawing-Rev1A.
pdf Inch-pounds = amount of torque required to lift a
1 pound weight 1 that is 1 inch from axis of rotation
Computing torque: Torque = Force * Moment Arm Torque = Weight (pounds) * moment arm (inches) Total torque = Sum of (weights * moment arms)
Page 14September 14, 2013
Design Engineering & Math Examples – Torque
PVC Pipe @ 0.21 lb/ft Grapple @ 0.5 lb Waste Cargo Ball @ 0.4 lb
Page 15September 14, 2013
Design Engineering & Math Examples – Torque
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
Page 16September 14, 2013
Torque = Weight (pounds) * moment arm (inches)
Design Engineering & Math Examples – Torque
2.22 ft-lbs = 26.64 in-lbs Large Motor torque = 23.53 in-lbs “Back to the drawing board”
Page 17September 14, 2013
Design Engineering & Math Examples – Motor Specs
Page 18September 14, 2013
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
Page 19September 14, 2013
Construction Tips
Materials Fabrication & Safety
Page 20September 14, 2013
Materials
Polypropylene Sheet Aluminum bar, rod, & sheet Steel all-thread rod Wood PVC pipe Electrical Fasteners Miscellaneous
Page 21September 14, 2013
Fabrication & SafetyClub Workshop
Location & Hours 999 Vallejo Street, east of I-25 and north of 8th Ave 7 days/week, 9a to 11p M-F; 8a to 11p, Sat & Sun
Cost: Special RM BEST rate Call 720-324-7222 for details
Tools Woodwork Shop, with CNC router Machine Shop Metal Shop
Classes www.clubworkshop.com
Page 22September 14, 2013
Fabrication & SafetyCutting Plastic Sheet (video)
Wear eye protection & secure work1. Scribe and break – Sturdy knife
Good for 1/8” sheet2. Jig saw – New blade, 10 teeth/inch3. Band saw – ½-wide blade, 14 teeth/inch
May cause melting4. Circular saw – Carbide tip, triple-chip
Plywood blade will cause melting5. Table saw – 60-80 teeth, triple-chip, 1/8 to
½ inch blade exposed Page 23September 14, 2013
Fabrication & SafetyCutting Aluminum Bar &
RodWear eye protection & secure work ½-inch Bar
Hacksaw: laborious and slow Jig saw: (see notes) Band saw: wood-cutting blade Horizontal band saw:
straight & safe Visit Club Workshop
Page 24September 14, 2013
Fabrication & SafetyCutting Aluminum Sheet
Tin Snips: laborious Stop short of full cut to
avoid cut marks Air or power shears Sheet metal shear
Visit Club Workshop
For marking, use ultrafine Sharpie
After cutting, dress edges with file
Page 25September 14, 2013
Fabrication & SafetyBending Aluminum Sheet
Page 26September 14, 2013
• Hand bender• Vise• Sheet metal brake
• Visit Club Workshop
Fabrication & SafetyPVC and Wood
PVC Hacksaw PVC cutter
Wood: Holes & round parts Drill Drill press Hole saw
Page 27September 14, 2013
Page 28September 14, 2013
Fabrication & SafetyDrill Press Speeds (rpm)
Page 29September 14, 2013
Bit Type Plywood& Pine
Acrylic Aluminum
Steel
Twist, 1/16” to 3/16” 3000 2500 3000 3000Twist, 1/4” to 3/8” 3000 2000 2500 1000Twist, 7/16” to 5/8” 1500 1500 1500 600Twist, 11/16” to 1” 750 NR 1000 350Hole Saw, 1” to 2.5” 500 NR 250 NRSpade bit w/ spurs, 3/8” to 1”
2000 500 NR NR
Circle Cutter, 1.5” to 3” 500 250 NR NRCircle Cutter, 3.25 to 6” 250 250 NR NRCircle cutters: Drill 1st side, flip material over, finish on 2nd side
Wear eye protection & secure work
Fabrication & Safety
Wear eye protection & secure work Center punch holes to prevent drill
from wandering
Clamp workPage 30September 14, 2013
Fabrication & SafetyFasteners – Drill and Tap
Page 31September 14, 2013
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 & SafetyElectrical Components
Page 32September 14, 2013
Proper connection of electrical components
Mount Cortex for easy access
Fabrication & SafetyLimit Switches
Page 33September 14, 2013
SubMini Snap
Connect to digital port: Closed = “0”; Open = “1”
Fabrication & SafetyVEX Motor Mounting Kit
Page 34September 14, 2013
• Specifically designed to mount BEST motors
• Flat, but designed to be easily bent
Fabrication & SafetyBEST References
http://best.eng.auburn.edu/b_game_rules.php http://best.eng.auburn.edu/stored_procedures/folder-manager/1. 2013 RMBEST Consumable Kit List2. 2013 RMBEST Returnable Kit List3. BEST Large Motor Spec Sheet4. BEST Small Motor Spec Sheet5. BEST Generic Kit Usage Guide6. 3.X VEXnet Firmware Upgrade Utility Operating Instructions and
Installation
7. Cortex Microcontroller and VEXnet Joystick User Guide
8. VEX Cortex Pin-out9. Introduction to easyC & Cortex (Intelitek)10. Google for PDF: “Tools, Tips and Materials” by David
KwastPage 35September 14, 2013
Club Workshop Location & Hours
999 Vallejo Street, east of I-25 and north of 8th Ave 7 days/week, 9a to 11p M-F; 8a to 11p, Sat & Sun
Cost: Special RM BEST rate Call 720-324-7222 for details
Tools Woodwork Shop, with CNC router Machine Shop Metal Shop
Classes www.clubworkshop.com
Page 36September 14, 2013