Tag: game analysis

The Path to Prototyping

In our first season (Nothing But Net), our team zeroed in on a double-flywheel design and ran with it; we didn’t know enough (or own enough parts, honestly) to brainstorm and prototype different designs. In our second season (Starstruck), we figured out some missing steps and did a more thorough analysis of the game rules (following the method outlined in the STEM Educational Video Online Challenge entry, “VEX Robotics Guide on Effective Game Analysis“) and did prototype different designs. However, the prototyping process was hard, the girls on the team were at a loss of how to start, and, frankly, I was at a loss on how to get them going.

Game Analysis

VEX In the Zone logoThis year (In The Zone), we took things to the next level. Even though the girls are now knowledgeable enough to jump right into building prototypes, I wouldn’t let them! Instead, we started with an even more complete game analysis than in the past (writing all of our work in our Engineering Notebook), including describing, in the girls’ own words:

  • Object of the game/description of game play
  • Playing area & field elements
  • Scoring objects
  • Ways to score
  • Rules about de-scoring, scoring for an opponent, and defense
  • Other special rules about scoring
  • Robot building constraints
  • Tournament rankings
  • Rule modifications for the Skills Challenge

Robot Strategy Brainstorming

After this process we were so so familiar with the rules and ways to score; we were then able to brainstorm different game/robot strategies. Note that I didn’t say brainstorm robot designs, but rather robot strategies. What do I mean by that? Well, we made a list of all of the different ways we could dream up to play this year’s game, such as:

  • be a defensive, wall-bot type of robot
  • be a cones-only robot, focusing on speed
  • be the highest-stack robot, focusing on height to be able to create the tallest stacks to win those bonus points
  • be a mobile-goal robot, focusing primarily on that aspect, with a limited cone-scoring capacity
  • be a jack-of-all-trades, control-your-own-destiny robot, and have mobile goal and reasonably tall cone-stacking ability
  • be a stack-as-you-go robot, carrying a mobile goal around and stacking cones on it as you go
  • be a “loader” robot, optimized for stacking cones from the loader onto a mobile goal

And so on. Under each strategy, we listed the required robot characteristics as well as pros and cons for each strategy. For example, one drawback of a defensive, wall-bot robot is that it is unable to score sufficient points to enter the Skills Challenge, which is important for our team. We also made a list of the characteristics or abilities we would want in every robot design.


Once we had all of the possible strategy-types detailed, the girls chose, as a group, what strategy they would like to pursue. Then I let them get their hands on some parts. We decided to be a jack-of-all-trades robot, with the ability to score mobile goals and cones.

  • We went back to our scoring analysis to estimate the height of a cone stack that we thought would be sufficient to win matches, in order to determine how tall the lift should be.
  • The girls researched different types of lifts (4-bar, 6-bar, 8-bar, double-reverse-4-bar, scissor, and elevator) and chose the one they thought would be most reliable and functional for stacking cones.
  • We evaluated the tasks our robot would need to do (such as getting over the starting bar) and listed all of the possible chassis designs and wheel types; the girls chose the one that would best fit those needs, combined with being able to accommodate the cone-lift and mobile goal lift.
  • We brainstormed and prototyped different mobile-goal lifting mechanisms and chose the one we thought would work best, noting that cones bounce off the mobile goals very easily if the goal is dropped, even from an inch or 2 off the ground.
  • The girls decided that a passive (non-motorized) cone-grabber/lifter was what they wanted—in order to save motors for other uses—and prototyped many different passive-intakes to attach to their lift (including looking at videos other teams have posted showing their designs). They chose one as “v1.0”, knowing that as the building process goes along, they might find deficiencies in this design, and find better ways to grab cones.

For all of these items, they included photos, drawings, and descriptions in their Engineering Notebook, and described, for each component, why they chose that design and why they did not choose the other ideas.

We had “robo camp” last week, and with 3 girls and about 35 hours, now have a functioning robot. But we could not have gotten to this point—by June 18—if we had jumped into prototyping without a coherent game strategy to base it on.

Next Steps

In The Zone - field view

Now we are going back to our game analysis and scoring options to brainstorm, with this robot design, what is the best way to spend the 15 seconds of autonomous, and best way to spend the 105 seconds of driver control to maximize this robot’s capabilities and win matches.

While we have a functioning robot now, it is not the world’s greatest-functioning robot! We are going back now to refine various components, write test programs, and see what we can perfect to make scoring easier.

Drive, Drive, Drive

VEX JoysticksThere’s no time like the present to get practicing on driving! There is absolutely no substitute for drive practice: given 2 identical robots, the team with more drive practice will always win (and will frequently beat out better designs too). Driving isn’t something that can be learned in one fell swoop in the week before a competition; small amounts of practice over a long period of time are what will produce a great drive team, especially if the team uses 2 joysticks and requires coordination between the 2 operators.

Teams that have a working robot sooner in the season will have the advantage of more practice before competition season starts.


Mentors: Know the Rules, Inside & Out

VEX In the Zone logoIf you are a coach or mentor out there reading this, I implore you to learn the rules like the back of your hand. (Act fast! Download your rule book today!) As a mentor, you should know the rules at least as well as any student on your team, and hopefully much better than that.

Why, exactly? First, the manual has rules about the construction of the robot—maximum dimensions, motors allowed, non-VEX parts allowed (or not)—and what’s permissible (or not) during match play. It’s your responsibility as a coach or mentor to keep your kids from going down a brainstorming–>prototyping–>building avenue that is out of spec, or that relies on a strategy that is actually against the rules. Alternately, teams can build a robot that doesn’t make use of the rules in the most effective way, and end up with a robot with lower capabilities than their competitors because “we didn’t know you were allowed to do that.”

Learning the rule book, in order of priority:

  1. In The Zone - game manual coverPrint out a hard copy that you can write on, including Appendix B (Skills Challenge Rules) and Appendix A (Field Specifications). Keep this copy where it can be consulted conveniently in your lab (I put mine in one of those manila folders with the 3-hole-punch metal “wings”). It’s easy to look things up if the rule manual is close at hand. Without it, it’s easy to ignore those small questions that turn out to have been really important. (Yes, yes, paper is old-school, but in this case it’s much, much better than reading the game manual PDF on an iPhone.)
  2. Know pages 3–17 “The Game” like nobody’s business. Getting there will require reading the manual more than once. (I recommend 3 times.) Get yourself a highlighter and a pen; make notes in the margins, underline things, circle things, whatever. And when you read it the second time (or the third), pay close attention to the things you didn’t highlight last go-around and see if you missed anything; it’s really easy to miss small details that make a huge difference. Sometimes the “robot-speak” of the rule manual obscures things on first read.
    • In The Zone - Skills Challenge rulesWhile you’re in rule-mode, read Appendix B – The Robot Skills Challenge. Skills challenge involves your team’s robot, on the field by itself, scoring as many points as possible in 60 seconds. There are separate scores for Driver Skills (student/joystick controlled) and for Programming Skills (same thing, but completely autonomous for the full 60 seconds); the total of the 2 scores is your team’s skills score that’s used for rankings. Skills Challenge has very similar rules to regular match play, but there are always a few wrinkles given that it’s not a 2-on-2 match. You need to know what the differences are between skills and match play. Again, know it like nobody’s business.
  3. Read pages 25–32 “The Robot” very closely. Take notes; highlight stuff. This section doesn’t change tremendously from year to year, but you still have to read all of it and understand exactly what building restrictions and limitations are in place for this year’s game, because something in there is going to be different from last year.
  4. Pages 18–24 “The Tournament” are critical to read if you’re new to VEX or maybe just have one season under your belt. This section explains how rankings are established: win points, autonomous points, and strength-of-schedule points (the latter being extremely confusing to all but the initiated). This section also describes how the alliance selection/playoff system works (also a bit mind-boggling if you’ve never seen it before). If you’re already familiar with tournament play, you still need to read this section once, thoroughly.
  5. Appendix A, Field Specifications. At first glance, this seems like an assembly manual for putting together a field perimeter. Yes, there are pages devoted to that; there are also the following very useful pages:
    • Page 3 has an excellent “skyline” view showing the game setup, as seen side-on. It gives you a better sense of the height of the different game pieces.
      In the Zone game pieces, side view
    • Page 9 shows exactly where to put down the white tape lines.
    • Page 17 has a complete list of all of the game pieces and where they will be placed at the start of the match.
    • Pages 21–27 show the exact dimensions of every single game element, like this:
      In The Zone -base dimensions      In The Zone - cone dimensions

Keep Tabs on the Forum

Even after all this reading, there will most likely still be things that you’ve overlooked. (This is not an insult! This happens to me every year!) So I also strongly recommend looking periodically at the VEX Forum, both in the Official In The Zone Q&A and the general In The Zone discussion. We’re all busy people, I get it; the good news is that you don’t have to read all of every post to learn stuff. First, look at the comment count over in the far-right column; a “0” means that no one has responded to that question at all, so you may just want to skip those until your next Forum visit.

Official In The Zone Q&A Forum

Start by cruising the Official Q&A channel first; questions here are answered by the horse’s mouth, so to speak. Many threads are answered by the famous Karthik himself, and each thread here is only one-item long because this channel permits no back-and-forth discussion. People ask a question, VEX answers it, and that’s the end of the story. Pay close attention to questions around specifically-named rules, especially if there’s a lot of questions about one particular rule. When you see this, there’s probably some subtlety in the rule’s wording that you have not yet noticed. In the game manual, rules are written something like <G6> for the 6th item listed in “The Game” section, or <R2> for the 2nd item in “The Robot” section, and people often reference these rules by name when they have a question.

General In The Zone Forum

Next go to the general In The Zone discussion forum; start by reading the topic titles and focus on ones related to strategy, rules, restrictions/limits, etc. (Beware, it’s easy to get sucked into reading long, not-related-to-the-rule-book threads.) Dive in!

Come Back! The Forum Is Lonely Without You!

Come back to the VEX Forum once a week or so and catch up on what the rest of the world has been talking about for this game; the Forum is basically crowd-sourcing ideas for you from all over the world—make the most of it!

Rules Updates Ahead!

If you’re a new coach out there, or this is your first time really diving into the rule book, it’s easy to overlook this tidbit on page 14:

All rules in this manual are subject to changes, and are not considered official until August 17th, 2017. We do not expect any major changes to take place, however we do reserve the right to make game changes until August 17th, 2017. There will also be scheduled manual updates on June 15th, 2017 and April 5th, 2018.

a. The Game Design Committee reserves the right to make changes to this manual in the April 5th, 2018 release specifically for the VEX Robotics World Championship. Specific items which will be considered for changes are the number of Cones and Mobile Goals.

What?!? These aren’t the final rules??? Yes, it’s true, these may not be the final rules that we will play by. However, we’re not going to all-of-a-sudden be picking up balls instead of cones, but there may be very important minor changes that affect your team’s strategy or the specifics of what you are permitted to do at various points in the game. In addition, there are often slight changes to game definitions or changes that serve to clarify an existing rule that may have had ambiguous wording.

Mark your calendars now for June 15th and August 17th—set an alert for those dates to remind you to get online and check. (I’m serious about that; it’s the middle of summer, and you will probably be thinking of other stuff.)

Incorporate the Changes into Your Hard Copy

You may have to poke around the forum to find a thread that just lists the changes; this saves you from having to do some crazy side-by-side comparison of versions to figure out what’s new. But wait! I’ve already highlighted & carefully marked up my current copy of the rules; do I have to do it all again?!? Well, what I did last year was print out the pages with the updated items, cut out the specific rules that were new, and tape them into my book, on top of the old rules. Sometimes you have to be creative here, since the new rules may take up more space on the page. Or you could cross out the old rule in your book and insert the new page after the existing page with the new stuff highlighted. You get the idea.

I’ll say it again here in closing: Mentors and Coaches, learn the rule book like the back of your hand!


Starstruck: Analyzing the New Game

Our team is really excited to dive into the new game: Starstruck.

As I mentioned in my very first post, one of last year’s online challenge entrants provides an excellent framework for analyzing any new VEX Robotics game: VEX Robotics Guide to Effective Game Analysis.

I highly recommend watching this helpful video yourself, but here’s a breakdown of their methodology:

  1. Watch the video of the new game
  2. Read the game manual (updated 2/2/17) and appendices (A – Field Specifications; B – Robot Skills)
  3. Read the manual again, this time making annotations on the important aspects of the game
    • how to score
    • build restrictions
  4. Read the manual again
    • highlight & understand all the ways to score points
    • most common way to score
    • most rewarding way to score
    • Do this for programming skills & driver skills manuals as well


    • how to de-score
    • how to keep your opponents from de-scoring you
    • Make lists of all of these things above for engineering notebook
  5. Break down the game into simple tasks that lead to winning matches
    • determine the most optimal, efficient, and reliable ways to win based on #3 and #4
    • make a list of all the ways to deny points, no matter how obscure they may be
  6. Make a list of all the building & design limitations
    • size constraints
    • motors/pneumatics
    • special rules that nullify or modify the above restrictions
  7. Determine what tasks the robot should be able to do
    • define clear objectives of what you want the robot to do (e.g., drive, pick up balls, shoot balls)
    • put objectives in one column of a table
    • in the next column, list quantitative abilities for each objective (how fast, how many balls, etc.)
  8. Make an overall schedule of work between now and your first competition.

Good luck!


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