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.
This 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.
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
There’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.