Day One

The first weekend of the build season was a flurry of activity. We managed to quickly go through the rules in our groups and presented five things that each group believed was important. Below are some of the highlights.

• Two (Station 1 and Station 3) of the driver stations are angled
• Robot sizing dimensions are < 125 lbs, 120″ frame perimeter, < 45″ tall, 12″ from frame perimeter limit at all times
• Only able to have 15 balls in your human player zone before you must reintroduce balls
• You are protected from being touched by another alliances robot in three sections of the field: your scoring zone, the loading zone and your trench (rules G10 and G11)
• Pinning rules are unchanged
• No full court shots
• The robot can only hold 5 power cells
• 3 Power cells may be preloads in auto

After the rule discussions, we started a scoring analysis and tried to figure out how to score points and what gets you the most points. Scoring in the low goal is worth one point, outer goal is worth 2, and inner goal is worth 3. These points are doubled in auto. Crossing the initiation line in auto is worth 5 points. During end game hanging is worth 25 points, and if the Generator Switch is level, you get a bonus 15 points (1 RP). Rotational control on the control panel is worth 10 points (this can only be completed after stage 2 power cell requirements have been met). Positional control is worth 20 points (this can only be completed after stage 3 power cell requirements have been met).

Scoring will win you a match but how do you turn that into winning a district event or a regional? That is where the ranking points come into play.

• Win – 2 RP
• Tie – 1 RP
• Having 65 or more End Game Points – 1 RP
• Getting Stage 3 Completed – 1 RP

Lets expand on completing stage 3, you have to complete the previous stage’s requirements before any of the requirements of the next stage can be completed. To complete stage 1, you must score 9 power cells and tele-operated control must start. Stage two gets harder, needing to score 20 power cells and completing rotational control on the control panel. Activating stage three requires 20 more power cells to be scored and completing positional control. This seems really hard to do alone. Just scoring the power cells is 10 cycles of 5 power cells. With 135 seconds of the tele-operated period minus 10 seconds for parking and a total of 30 seconds for control panel interactions, that’s a cycle every 9 seconds. In order to achieve that ranking point by yourself, you will need to find balls closer than your loading station, or shoot from far away with good accuracy. This ranking point is going to be too difficult to do solo. If you have just one alliance partner who is capable of scoring 3 cycles of 5 power cells, your cycle time is increased to 12 seconds a cycle. This might be doable.

The hanging RP is just as difficult to achieve alone, although the challenge is in the design and mechanical complexity of the task. If you are able to carry a partner to hang and level the generator switch, you gain 65 points and a RP. That is a very lucrative strategy if you are able to design a mechanism that can accomplish the hang and level quickly, is repeatable with any bot, and is durable.

So both extra RPs are hard to do alone. For an above average team, it seems like a good idea to score as many points in the outer goal of the power port and hang on the generator switch. If you are capable of scoring 30 balls into the outer goal you get 60 points, add a hang into there for another 25, getting a total of 85 points in tele-operated period. You could get 17 bonus points with a working autonomous, if you shoot your 3 preloads and move past the initiation line. If you do that every match at a week one or week two event, you could end up seeding very high.

The field build this year doesn’t seem to be that bad compared to last year, we are only going to build a loading station, power port, and one generator switch. Its unfortunate that the game requires a full field as we are only able to fit about 60% of a field length-wise in our shop. We will have to scale it down.

Next Steps?

After talking about scoring, we started talking about how difficult each task is and long it would take to do each task. We are worried that we won’t be able to do enough cycles with scoring power cells to leave time to complete the additional control panel requirements of each stage. 10 cycles to get all the power cell requirements seems like something only 254 will be able to do repeatedly. This leaves the end game RP as the only bonus RP that we might be able to achieve solo.

We spent a lot of time discussing which direction we should focus or efforts on. The possibility to earn a bonus RP is a huge carrot at the end of a long stick. Being able to quickly shoot into the outer goal and earn points is another carrot on a slightly shorter stick. We disagreed on the length of the stick and decided we needed some more information on how hard each task is. We seem to be at a point that the control panel wheel is something that will get added to the robot much later. We made a list of things that we needed to prototype in order to find out how difficult each task is.

• Power cell overhead rolling intake
• Fly wheel shooter
• Double climb
• Internal ball conveyor

Day Two

With our list of things to prototype, we broke down into groups and set out to it. We quickly had a prototype of a fly wheel shooter with different slots for a piece of polycarb to test out compression. We found that compressing the ball 1 1/2″ provided a nice repeatable trajectory. Until the slots broke. A lack of material and deep slotting caused the ribs to break. We quickly drew up a new fixture and cut another one on the router that only had the slot for 1 1/2″ of compression. We were using some Banebot 4 7/8″ wheels with a 775pro on a 4:1 planetary gearbox. Our next steps with this prototype is to change out the wheels to a 4″ colson wheel, and work on finalizing the angle of the hood and improving consistency. We only have one power cell at the moment so we need the others to arrive before we can test rapid fire.

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Another group was working on prototyping an overhead roller intake using Protopipe from Spectrum. This group rapidly progressed and was intaking a ball with a pool noodle quickly. They decided to change out the pool noodle roller for small vectored intake wheels, and found that the protopipe was flexing too much. The next steps for the intake prototype is drawing up a version and cutting a plywood version. We are still debating if we will have a bumper cut out or not.

The double climb group discussed a bunch of different ideas and every one we came up with seemed to have us confirming that this task is really challenging. Hopefully we can think of something encouraging soon.

Our programming group started working with the color sensor provided in the kit of parts, and managed to get that up and running quickly. They also had students working on getting pathweaver working with the updates for 2020.

During this time we had some students and mentors working on finishing up the field perimeter, and started building the field elements. Having a router makes cutting the plywood so much quicker. It has also been an insane improvement for prototyping.

Drive Base Work

We made the decision that we could probably work our designs into the drive base configuration and decided to set some numbers for the drive base. Ending up with a mostly square robot, with a 6-wheel west coast drive with pneumatic tires. This is the earliest we’ve ever finalized a drive base design, but I don’t think it should be much of a problem.

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The drawings for the drive base were finished about 3pm on Sunday and were handed over to manufacturing. This is where we quickly discovered we did not have enough material on hand for two drive bases. We are building two robots this year, and as it turns out that means double of everything. Oh well! A Monday morning run to our metal supplier will take care of that problem.

Our design team used ILITE drive train simulator to calculate the time it takes for a robot to go different distances. We are using a single speed gear box this year, as we haven’t been able to make enough use out of shifting gearbox to justify the added complexity and cost. Right now we have gearing for a theoretical max speed of 15.4 fps.

Our team doesn’t have an official meeting tomorrow so the next post will be thoughts about scoring and some analysis on past games with similar scoring. We meet again on Tuesday.