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 Process Importance  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 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: Ref: -> Participants -> File Manager > Public Resources & Training > Team Resources > Engineering Topicshttp://best.eng.auburn.edu/ Page 4September 14, 2013

1) Define the Problem  Read the Rules thoroughly at  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 lbs Page 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  Programming Page 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 & Documentation Important 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 13 September 14, 2013

Design Engineering & Math Examples – Torque  Dimensions and torque  Small Motor   Large Motor   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 0.21 lb/ft  0.5 lb  Waste Cargo 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: =2.22 ft-lbs Page 16September 14, 2013 Torque = Weight (pounds) * moment arm (inches)

Design Engineering & Math Examples – Torque  2.22 ft-lbs = in-lbs  Large Motor torque = 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) Torque: 2.75 in-lb(44 oz-in) Gear Type: Plastic Gear Type: Plastic BEST Small Motor Torque: 9.49 in-lb (152 oz-in) Torque: 9.49 in-lb (152 oz-in) BEST Large Motor Torque: in-lb ( oz-in) Torque: in-lb ( 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:  easyC example:  Wiring example: me_brew/potentiometer/potentiometer.swf me_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 & Safety Club Workshop  Location & Hours  999 Vallejo Street, east of I-25 and north of 8 th Ave  7 days/week, 9a to 11p M-F; 8a to 11p, Sat & Sun  Cost:  Special RM BEST rate  Call for details  Tools  Woodwork Shop, with CNC router  Machine Shop  Metal Shop  Classes  Page 22September 14, 2013

Fabrication & Safety Cutting Plastic Sheet (video) 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 – teeth, triple-chip, 1/8 to ½ inch blade exposed Page 23September 14, 2013

Fabrication & Safety Cutting Aluminum Bar & Rod Wear 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 & Safety Cutting 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 & Safety Bending Aluminum Sheet Page 26September 14, 2013 Hand bender Hand bender Vise Vise Sheet metal brake Sheet metal brake Visit Club Workshop Visit Club Workshop

Fabrication & Safety PVC and Wood  PVC  Hacksaw  PVC cutter  Wood: Holes & round parts  Drill  Drill press  Hole saw Page 27September 14, 2013

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Fabrication & Safety Drill Press Speeds (rpm) Page 29September 14, 2013 Bit TypePlywood & Pine AcrylicAluminumSteel Twist, 1/16” to 3/16” Twist, 1/4” to 3/8” Twist, 7/16” to 5/8” Twist, 11/16” to 1”750NR Hole Saw, 1” to 2.5”500NR250NR Spade bit w/ spurs, 3/8” to 1” NR Circle Cutter, 1.5” to 3”500250NR Circle Cutter, 3.25 to 6”250 NR Circle cutters: Drill 1 st side, flip material over, finish on 2 nd side Wear eye protection & secure work

Fabrication & Safety Wear eye protection & secure work  Center punch holes to prevent drill from wandering  Clamp work Page 30September 14, 2013

Fabrication & Safety Fasteners – Drill and Tap Page 31September 14, 2013 Machine Screw Drill Bit Number 1/4”-208 # # Threads are cut inside a hole using a tap Threads are cut inside a hole using a tap Match hole size (numbered drill bit) to screw Match hole size (numbered drill bit) to screw Screws: size – threads/inch Screws: size – threads/inch Purchase drill/tap sets at Ace Hardware Purchase drill/tap sets at Ace Hardware

Fabrication & Safety Electrical Components Page 32September 14, 2013 Proper connection of electrical components Mount Cortex for easy access

Fabrication & Safety Limit Switches Page 33September 14, 2013 SubMini Snap Connect to digital port: Closed = “0”; Open = “1”

Fabrication & Safety VEX Motor Mounting Kit Page 34September 14, 2013 Specifically designed to mount BEST motors Specifically designed to mount BEST motors Flat, but designed to be easily bent Flat, but designed to be easily bent

Fabrication & Safety BEST References   RMBEST Consumable Kit List RMBEST Returnable Kit List 3. BEST Large Motor Spec Sheet 4. BEST Small Motor Spec Sheet 5. BEST Generic Kit Usage Guide 6. 3.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 Page 35September 14, 2013

Club Workshop  Location & Hours  999 Vallejo Street, east of I-25 and north of 8 th Ave  7 days/week, 9a to 11p M-F; 8a to 11p, Sat & Sun  Cost:  Special RM BEST rate  Call for details  Tools  Woodwork Shop, with CNC router  Machine Shop  Metal Shop  Classes  Page 36September 14, 2013