Wiki

[technik3k]

VEX Forum Wiki Rules and Style Guidelines

As was already said in the introduction, the purpose of this topic is not to duplicate vast amounts of knowledge already available on the Vex Forum and external sites, but to make it easy to find that information.

We welcome and value all contributions and currently any forum users with TL1 trust level could edit Wiki posts.

However, to maintain high quality of the Wiki, everybody has to adhere to the Wiki Guidelines, that are detailed below.

Please, DO NOT CREATE NEW POSTS in this topic, unless you have a prior approval from the Wiki maintainers team (TBD).

Current open discussion about this wiki could be found in this thread: VEX Forum Wiki

This Style and contribution Guidelines are work in progress and we are going to define and put them here in the near future…

In general, the preference is to stay brief and, whenever possible, use a link to an existing topic, instead of copying its content into the Wiki.

Strategy

We could start by listing things “we wish we knew at the beginning” and then sort them into beginner / intermediate / advanced categories.

Beginner category is something that needs to be communicated right away.
Intermediate is something that could wait until later in the season or second season.
And advanced is something (like odometry/tracking) that would be great to get to, but is not required by most of the teams.

If we use pyramid diagram, then we could start from the top with the most basic and most important knowledge, then expand it into intermediate level, with more information that relies on more prior experience, and so forth …

[technik3k]

Building the robot - what constitutes the robot - basics

VRC Legal definition of the robot (according to the Game Manual <R1>)

One Robot per Team. Only one (1) Robot will be allowed to compete per Team in the VEX Robotics Competition. Though it is expected that Teams will make changes to their Robot at the competition, a Team is limited to only one (1) Robot. As such, a VEX Robot, for the purposes of the VEX Robotics Competition, has the following subsystems:

• Subsystem 1: Mobile robotic base including wheels, tracks, legs, or any other mechanism that allows the robot to navigate the majority of the flat playing field surface. For a stationary Robot, the robotic base without wheels would be considered Subsystem 1.

• Subsystem 2: Power and control system that includes a legal VEX battery, a legal VEX control system, and associated motors for the mobile robotic base.

• Subsystem 3: Additional mechanisms (and associated motors) that allow manipulation of game objects or navigation of field obstacles.

Given the above definitions, a minimum Robot for use in any VEX Robotics Competition event (including Skills Challenges) must consist of 1 and 2 above.

TBD

Example

https://www.youtube.com/watch?v=3yedhYdeiLM

Details

Brain, Battery, VexNet, and most importantly license plates: 7580A 2015 Robot Reveal.

Just kidding

https://help.vex.com/category/369-engineering

[technik3k]

Overview of common chassis types

How could we help a new team to choose a chassis for the robot?

https://help.vex.com/article/372-how-to-select-a-drivetrain

Robot Subsystem #1: Chassis

It is very important to select the proper drivetrain for your robot. You need to consider specifics of the game. Your driving style and experience, as well as requirements for lateral movement, power, and speed among other factors are integral to selection of a drivetrain.

Tank drive is most common type of drive seen, as well as the simplest. A Tank drive consists of two rows of wheels parallel to each other on either side of the robot. There are many different subsets, including 4-wheel, 6-wheel, and whether the use of traction wheels included as any of the sets of the wheels.

H-Drives are built as Tank drives are, except there are wheel(s) mounted perpendicular to the drive which allow for lateral movement. All wheels must be omni wheels for the drive to be able to function.

Holonomic drive, also called an X-Drive, consists of wheels mounted at angles from each other. It is good for lateral movement, and increases speed and power of turns. However, linear drive speed and power are decreased due to the nature of how wheels run toward each other to move linearly. All wheels must be omni wheels in order for this drive to function.

Mecanum drive uses 4 mechanum wheels to move linearly forward, backward, left, and right. Mechanum drives are much harder for another robot to push around, however are usually slower than a H-drive.

Drivetrain Type	Pros	Cons
1. All omni tank drive	- easy to build	- can be easily pushed to the side
	- 2 or 4 motors
	- can be chained front-back
2. H-Drive	- all advantages of tank drive	- needs extra motor
		- tricky to distribute weight
3. X-Drive	- resists pushing	- harder to build
4. Mecanum	TBD	- requires 4 motors

Omni wheel vs Mecanum

[technik3k]

Overview of frequently used Lift Types

Robot Subsystem #2: Lift

1. 2-bar
2. 4-bar, 6-bar (n-bar)
3. DR4B
4. Cascade
5. Chain-bar
   …

[technik3k]

Overview of frequently used intakes

Robot Subsystem #3: Object Manipulator

1. Claw
2. Side rollers
3. Top roller
4. Forklift
5. Passive (pneumatics)

[technik3k]

Best Building practices (general)

• bearings

• screw joints

• Types of nuts

  • Nylocks are heavier, but have much greater grip. They likely will not significantly loosen even after extensive use. Additionally, not tightening them (and allowing the screw to spin freely) is perfect for rotating joints.
  • Keps are lighter and are the quickest to use. Their teeth help maintain its position when tightened, but not as much as nylocks and cannot be rotated once tightened. Perfect for prototyping or securing less vital structure.
  • Plain nuts are the lightest and are used mostly on parts with places for the nuts designed onto them, such as the clamping shaft collar or V2 rack gears.

• basic gear ratios

  • Builders can trade motor speed for motor torque (and vice versa) by using a system of gears to change the speed of the output shaft.
  • gears have a set number of teeth, and when gears mesh, the output gear rotates however many teeth the input rotated, not the number of rotations the shaft went through. Builders can use this to their advantage so that the output gear rotates faster, but with less torque (larger gear -> smaller gear), or slower but with increased torque (smaller gear -> larger gear).
  • If gear sizes become too extreme, more advanced builders may use compound gearing to exponentially modify their gear ratios. This is done by having the output shaft from previous gearing become the input shaft for more gearing with different gear sizes.

• no cantilevered drive wheels

  • As a general rule, for anything on a shaft other than shaft collars and washers, the shaft should be secured to structure on both sides of whatever it is supporting.
  • Not doing this results in the shaft having a lot of wiggle room, as typically seen when wheels are exposed on the outside of a robot.

• spacers, standoffs mounting

• use all omni drive base with 4 motors

DR4B Tutorial by 333A

Building Tips

VEX Build Quality Tutorial/Instruction video:

[technik3k]

Other important build topics and examples

TBD General

• Geartrains
• Chaindrives

Wallbots (not TT specific):

1471A Toss Up Wallbot Reveal "Apophis" AKA The Quadropus

This is the reveal for the wallbot we brought to Worlds. As far as we know, this is the largest robot in VEX history. Sadly we do not have any footage of it, but you can check out the livestream archives from worlds if you’d like to see. Our final match was Q195 in the Engineering division. Pictures are here: https://www.flickr.com/photos/123583170@N08/sets/72157644089099400/ [image] [image] This robot was built in about tw…

2W 2012 Gateway Robot

Ok, so say I’m wrong and attaching was legal. And I actually competed this year, building a different robot than what I planned. It would have the same concept just designing was a little harder when things didnt works so nicely for “locking”. What this robot was going to do was lock onto the center portion where the gates rest using a piston and mechancial latch that would be insanely protected to it doesn’t even scratch the field. After that An elastic elevator would go up, and an 8 foot tel…

GOATs in VEX

Actual GOAT defensive bot 2W Gateway world champs

GOATs in VEX

GOAT Wallbot Nominee 127C - Worlds Match

VEX Reference Build instructions for starter kits

Tower Takeover Season Specific

Theory:

Physics of Tilter
How To Fix Intake Compression [Guide]
…

Showcase Tilters:

448X, 21S, 6671X, and 1437Z RI3D Reveal
1961Z Tower Takeover Teaser: Mk. III
42700N Summer Reveal
25461Z early season reveal: https://youtu.be/Wvz_8Ja-JQw

Showcase DR4Bs:

97963A Early Season Reveal
Robot in 3 Days Reveal: Houdini | 9605A + 9421
VEX Tower Takeover 21000C 66 Point Driver Skills (Robo Bonanza @ Beckman)

Showcase Wallbots:

2019 NorCal RI3D Reveal

[technik3k]

Programming environments, links to help and tutorials

https://www.learncpp.com
https://www.tutorialspoint.com/cprogramming/index.htm

V5:

• https://www.vexrobotics.com/vexcode
• https://www.vexrobotics.com/vexcode-download
  – https://help.vex.com/category/130-getting-started
  – https://www.youtube.com/user/vexroboticstv/search?query=vexcode
• Robot Mesh Studio: https://www.robotmesh.com/studio/
• PROS: https://pros.cs.purdue.edu/

Cortex:

• RobotC: https://www.vexrobotics.com/robotc-vexedr-vexiq.html
• EasyC: https://shop.intelitek.com/easyC-V6-for-IQEDR--Perpetual_p_122.html

TBD: Supported languages, platforms, blocks vs text, which one to choose…

API Reference:

• https://api.vexcode.cloud/v5/html/
• https://help.vexcodingstudio.com/
• https://pros.cs.purdue.edu/v5/api/index.html
• https://www.robotmesh.com/docs/vexv5-cpp/html/namespacevex.html
• https://www.robotmesh.com/docs/vexcortex-python/html/index.html

Tutorials

• https://education.vex.com/eduvex/edr/stem-labs/
• https://www.youtube.com/channel/UC5ncWDIcFSMZKj_jH-7EOyg/playlists
• https://medium.com/thefloatingpoint/autonomous-driving-tutorial-for-vex-v5-robots-774703ca2d3c

LVGL:

• https://team81k.github.io/ProsLVGLTutorial/

For pre-V5 (Cortex) hardware:

https://www.robotc.net/wikiarchive/Tutorials/Getting_Started/Getting_Started_with_the_VEX_CORTEX

[technik3k]

Programming: Getting Started with VEXcode

https://help.vex.com/category/130-getting-started

• Motor config
• Sensor config
• Competition template

How to Create a Project Using the Competition Template - VEXcode V5 Text -...

VEXcode, motor groups and drivetrain example
VEXcode for experts

vexforum.com/t/autonomous-help-with-vexcode/71698/2

https://help.vex.com/article/110-vex-example-program-with-controller-c-arcade-drive

http://www.cplusplus.com/doc/tutorial/

[technik3k]

Programming: Common Beginner Mistakes and FAQs

TBD

Note:

make process closed with exit code : 2 means ‘code could not compile, your code probably has errors’. When creating a thread for help, please attach the whole log with your code.

https://help.vex.com/article/120-how-to-use-blocking-vs-non-blocking-code

Force Compile of Files

[technik3k]

V5 Architecture and Troubleshooting

V5 System Architecture

V5 architecture diagram (may need to move to advanced topics): The PROS of PROS

V5 Troubleshooting:

• Invalid Asset Table/Battery Medic: V5 Brain “Invalid Asset Table Version”

• Red Controller Screen: V5 Controller shows red screen and computer/brain icon

• Controller Vibrating: V5 Controller keeps vibrating

• V5 Brain won't connect to computer

• https://help.vex.com/article/143-how-to-use-the-battery-medic-to-diagnose-the-internal-state-of-the-battery
  https://help.vex.com/article/142-how-to-interpret-error-messages-with-the-v5-battery

Tips/warnings for v5?

• V5 mini USB Port / use magnetic cable
• V5 Motor inserts / be careful
• V5 ports and static

V5 battery diagnostics

I’m going to explain a little more about the V5 battery in this topic and specifically what information the battery medic diagnostic tool is showing. We have released some reference material on the V5 battery in the past, but never discussed in detail what some of the terms actually mean. An explanation of the battery led display is here. and the steps for running the battery diagnostic tool here. [medic_ref] The battery monitor shows some detailed information about the internal state…

Make sure you have installed the latest VexOS firmware which could be found here:

VEXos (Firmware)

Make sure that radio type is to VEXnet and not Bluetooth:

How to Pair the V5 Controller to the V5 Robot Brain - VEX Robotics Knowledge...

Auto not running off comp switch

with your program running you can check competition switch status both on the controller status bar and also the brain.

run your program. press the button on the V5 brain to toggle between the user program screen and the vexos screen.

[technik3k]

Engineering Design Process

https://www.google.com/search?q=engineering+design+process
TBD

[technik3k]

Engineering Notebook Resources

(Screen for redundant / duplicate topics)

Design Award Tips? - #2 by tabor473
Starting the Engineering Notebook
2915A Engineering Notebook 2016
Notebook Tips
Engineering Notebook Tips Selection and Strategy
How should I start off my notebook? (Summer without teammates)
what are Some Tips to add to the Notebook?
Engineering Notebook Expectations At Worlds
Example of an award winning notebook?
What is the best piece of advice you could give for an engineering notebook to be successful?
Notebook setup/layout

Starting an Engineering Notebook

Engineering Notebook & Design Award (Updated 2018) • Renegade Robotics

engineering notebook 1575A 2015-2016.pdf (45.0 MB)

How to Start an Award Winning VEX Notebook

@2775Josh

Of course your best option is to look page 26 of the Vex Judge’s Guide

Journal Overview - 6030J

Hello everyone! Here is a video overview with our engineering notebook from this year’s game, Tower Takeover. Since the season is basically over, I’d like to share some portions of it with you all. Journaling can be super boring and tedious at times, but if you keep up with it, your hard work will pay off. Enjoy! VEX Journal Overview - 6030J

VEX Journal Overview — 6030J

With permission from Keilan, Alumni of 590B:
Instance of a World-Winning Engineering Notebook From VEX Worlds 2019

EngNotebookVol1.pdf

Notebook Vol 2

This notebook helped give 590B Design Award at:
2019 VEX Robotics World Championship - VEX Robotics Competition High School Division

[technik3k]

CAD software: links, tutorials, tips

CAD Requirements?

Unless you bound-and-determined to use Fusion, take a look at Onshape. It is a CAD package as powerful as Solidworks, but runs on the Onshape server, not your local system. More details about all commercial CAD software here: CAD for VEX Robotics.pdf (299.7 KB)

VEX w/ Fusion 360 Tutorials

https://www.autodesk.com/education/competitions-and-events/vex/recommended-software

[technik3k]

Preparing for the competition day

References (redundant?):

https://www.roboticseducation.org/resources-library/
101 Things I Wish I'd Known Before My First VEX Tournament
Advice for first competition?

https://www.vexwiki.org/robotics_competitions/101_things
https://www.roboticseducation.org/documents/2013/06/101-things.pdf/

[technik3k]

Tips on how competition works

To be expanded:

• Qualifications
• Scouting:
  At tournaments, there are various ways of scouting that can be done to improve your chances of doing well. They are as follows:

• Match scouting: Before each qualification match, it is extremely important that you go and talk to your alliance partner, to coordinate autonomous programs, match strategies, and any other miscellaneous aspects to the upcoming match. This will also tie in with the second way if scouting.

• General tournament scouting: Throughout s tournament, it is helpful to take notes on each team/robot in attendance. Whether it be a quick robot summary, or detailed notes on the successes and weak points of each mechanism, doing so will allow you to be better prepared for your matches. This ties in to the 1st way of scouting, as you should be taking down notes on your alliance partners and opponents after every match.

When it comes time for alliance selection, having notes and scouting data is extremely helpful when deciding on who to pick for the elimination bracket. They will also help you to find any “hidden gems” that might be a better pick than some of the higher ranked robots. Scouting will also prepare you if a team decides to use the “scorched earth” strategy (go down the line of teams and ask each one until one accepts) to mess up any potential powerhouse alliances.

• Alliance selection
• BO1
• Skills
• Judging
• Who qualifies

[technik3k]

Beyond the competition

What else is there in VRC beyond going to competitions?

[technik3k]

School based vs independent team / fundraising

TBD

[technik3k]

Tips for organizing the team

Getting Started in Robotics (Tips and Advice)

https://www.roboticseducation.org/resources_library/how-to-start-and-organize-a-vrc-team/

List of products/items to purchase?
What parts should I not buy?

Should this be here or moved up to post 25?
Help motivating procrastinators to do their job
How to help combat un-involved team members

How many people on a team?

[technik3k]

Tools

Sort tools in order of importance…
Add pictures?

• wrenches 1/4, 11/32
• screwdrivers hex (5/64,3/32), star (T?)
• pliers, needlenose pliers, diagonal cutters, etc…
• tabletop grinder
• dremel

Custom Tools:

…

Tips:

Don’t strip screw heads - sharpen Hex screwdrivers regularly!

…

Safety considerations:

Wear goggles!!!
…

Color coding screwdrivres and wrenches:

Special tools

Insert puller:

Drilling template:

Bearing cutting template: