2425: Post-States Summary

VEX V5 General Discussion VEX Robot Showcase
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This thread is more of a summary thread rather than a reveal thread (it’s not like we post new stuff every week anything). Since the weekly updates are quite elaborate, this will just summarize our awards/abilities so far.
http://www.hydrarobotics.com/uploads/9/0/7/5/9075173/2446938_orig.jpg

Competition History:

  1. Qualifier: Design award winner. Quarter Finalist
  2. Qualifier: Excellence award winner. Quarter Finalist Alliance captain
  3. Qualifier: Design award winner. Finalist
  4. States: Create award winner. Tournament Champion

Overview and strategy
For the most part, the heart of mechanics is fairly standard: 4 motor drive, magic intake, fast lift. However, what set us apart in competitions we’ve participated in were strategy and autonomous - especially autonomous.

By states, we could theoretically score 18 points. However, we consistently scored 16 points with a maximum of 17 points. This was enough to 2 vs 1 most teams in our region during autonomous. Despite this emphasis, we did not want to slow our driver control play like the standard “push 2 large balls and stash a bucky ball” strategy, or the “hanging in auto strategy”. With our autonomous, we usually got 3 balls into the goal zone, which sped up bucky ball stashing for ourselves, or our ally during driver control, helping us equalize with column goals. Finally, we would resort to other standard tactics: flanking bucky ball robots with large balls, de-scoring large balls through storing, parking in front of the goals, etc. to earn a win.

As the season continued, our weakness moved from poor bucky ball abilities to simple mistakes such as turning on the robot (derp), or connection issues

Mechanics
Drive train: 4 motor; Mecanum Drive; internally geared for speed (1:1.6). Despite having mecanum wheels, the drive train did not have the ability to strafe. The drive train used a combination of pillow blocks and keps nuts as spacers to elevate the drivetrain and pass the bump as quickly as possible.
http://www.hydrarobotics.com/uploads/9/0/7/5/9075173/2396320_orig.jpg

Lift: 3 motor; Chain Bar; Geared 5:1 torque, elastic assist. This does not have the ability to hang. The extra torque and force from the extra motors and elastic assist keeps our lift system extremely quick and reliable to give us a minute advantage over standard, non-hanging lifts, and minimize lost ground from hanging robots. Modularized motors allow for quick repairs in times of need. Mechanical limiters are tuned to the appropriate height to score bucky balls and de-score/stash large balls and lowering the lift without dragging
http://www.hydrarobotics.com/uploads/9/0/7/5/9075173/6044232_orig.jpg

Intake: 2, 269 motors; Magic Intake; 1:1. Stores 3 bucky balls, as well as grab objects interchangeably. The zip ties create a flexible large ball storage to hold 2 balls, and can help guide any bucky balls fed by our allies.
http://www.hydrarobotics.com/uploads/9/0/7/5/9075173/9797354_orig.jpg

Funnels: 1 motor 6:1 torque; Used to grab bucky balls off the bump in autonomous, wall off areas, and push numerous large balls into a desired position.
http://www.hydrarobotics.com/uploads/9/0/7/5/9075173/1557777_orig.jpg

Programming Highlights
Middle Zone Autonomous: Starts off by grabbing the bucky balls off the bump while closing off defensive programs. Then it dumps bucky balls into the goal zone while knocking a large ball. It knocks the second large ball while backing up slightly without returning to the alliance tile. This last step opens up 2 base strategies. The first is to take advantage of our 3 bucky balls in the goal zone, the second is to grab the opposing alliances bucky balls typically knocked from the hanging zone autonomous.

Hanging Zone: Standard opening: knock off the bump buckies while grabbing a large ball. Grab the corner buckies. If alliance partner allows, trigger a sensor to bring the robot as close as possible into the goal zone

“Ghost Power”: We have no clue what’s the real name (if it has a name), so we created our own jargon. Essentially, it’s an easier version of PID control. The robot takes whatever the last control of the system was, and leaves it at a similar power value with low power. For example, if the lift is up, the lift will keep a small power value which keeps it up. If the lift is down, the lift will keep a small power value to keep the lift down. This slight trickle of power trades battery life for control.

“Cuarax Button”: Named after an ID typo of one of our freshmen. This button triggers alternative autonomous sequences under the event of defense, or a messed up play in programming skills

Future Stuff:
We plan on aiming for a new strategy, which requires revamping our drivetrain, funnels system, and autonomous. More details will come in our weekly updates.

**Footage

Semi Final 2(Won 61-44): Vex Toss Up: Florida States Semi 1-2 - YouTube**

Qualification Match 55(Won 46-42): https://www.youtube.com/watch?v=2d_cBWIHx78&list=UU6d9PnePfpUGmpxSzoDciBg

Magic Intake:https://www.youtube.com/watch?v=TQi7GHPwmM4

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Looks like a great robot!! Nice job winning your state tournament, and good luck at Worlds if you attend! :slight_smile:

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I am really impressed by this robot and your blog - great job!

Can you elaborate more on your funnel system? (now or after worlds I understand if you want to hold off) From what I can see it is one motor mechanically coupled to two 36 tooth gears which then goes to a ton of chain to manage some old style linear slides that pop out with rubber bands. You can move it out and in but once unfurled, the linear slides stay long I guess?

Your video of getting three off the bump in auton is an excellent strategy! How predictable did that work out for you? I’d imagine those buckeys would roll around pretty randomly inside the V of the funnel in front.

I also noticed a lack of sensors on the robot. Is your auton completely time based? No IME’s or quads that I could see, no potentiomenter on the arm either but you have mechanical stops for all the way up and down. There is the button on the back though…

Lastly, since you say you can’t strafe, will you switch from mechanums at this point for some more speed? You need a bunch more torque to turn those mechanums.

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Thank you:). We will be attending worlds, however, this is the first time in 5 years our team has actually attended. Because of this, everyone on my team is new to this experience.

Thanks:). As for the funnels, The second photo on this thread is actually a bit misleading(this was basically a scrapbook of major photos till states). My bad.

For states, it’s just a half of a linear slide bar on each side of the drive train which swings out through massive chaining without expansions

At our first competition we ditched the expanding linear slides idea because the elastic force needed to expand the funnels increased frictional force so much that expansion was unreliable, and it’s massive size created huge torque decay and awkwardness to use. Though it may have been possible, due to our time constraints, we couldn’t tune the system to how we wanted. You were correct about it’s expansion though. If it did expand, the robot would not retract the newly elongated wings. Rather, it would just poke out in the back of the robot…
However, you are correct that we use a lot of chain spread out among the innards of the drive train.

Now for specifics.

As of states, the funnels were built directly on top of the drive train, above the wheels. A layer of rails was mounted directly on top of the drive train, elevated by standoffs like pilings on a beach house. This layer is the layer where the cortex is mounted in our early stages (the cortex was moved by states)
http://www.hydrarobotics.com/uploads/9/0/7/5/9075173/1496128.jpg

The second stage of chaining, and the funnels system rests on top of this layer. To eliminate cantilevering and stabilize the funnels, a second layer is mounted, securing the funnels. This chaining held our 18 tooth gear and 6 tooth gear. This 18 tooth gear was used so the sprocket could be directly screwed into the funnels like a gear tower
http://www.hydrarobotics.com/uploads/9/0/7/5/9075173/3405196_orig.jpg

Like a combination gear tower, the first stage of chaining had the 12 tooth sprocket mounted to the 6 tooth sprocket. This 12 tooth sprocket was sandwiched between the drive train and first layer, completing the gear ratio of 6:1 torque. Both sides of the funnels, as you said, were then connected by two 36-tooth gears in the 5th image of my post. However, what’s not shown in that photo is that a strip of scrap 1 by 25 bar that encases the gears, removing cantilevering, and thus removing skipping issues we would experience without it.

Now for the actual bar which contacts the bucky balls. We kept the linear slide in place for two main reasons, we were willing to try expansions again, and swapping it with a rail or channel that was 12.5 inches long would of made very little difference. On the funnels, there are hooks, made of scrap 1 by 25 bar from previous seasons, and lock plates to create an angle of about 70ish degrees. We haven’t played with the angle, but we do not think it’s that important. Also, due to the structure of the funnel, being elevated above the drivetrain wheels, the funnels do not have the ability to manipulate bucky balls on the ground, nor do we need to due to the magic intake.

To be honest, we only got all 3 bucky balls off the bump once in all of our runs. However, after about 3 weeks of tuning (I think), or about a real time of about 8 hours, we’ve consistently grabbed 2 bucky balls. In states, we grabbed at least two in 6 of the 9 matches we participated in. However, in the 3 matches we didn’t grab 2, one was because our robot was off during autonomous (derp), and the other was because we disconnected. In the match we disconnected, an announcement was then made to turn off all wifi hotspots, so that’s probably the reason why we died.
As for counters, we’ve had this autonomous layout for 3 competitions. So far, no one has attempted a counter. Because grabbing the bucky balls is the first thing we do, the robot is 16 pounds, we have a standard 1:1.6 speed ratio, and the sequences are strung together tightly, we believe it’ll be very difficult for anyone to even attempt a successful counter.
Surprisingly, the difficult part of this autonomous isn’t grabbing the balls when it’s in front of the robot; The funnels nicely feeds the already effective magic intake. The difficult part is capturing all 3 balls before they fall into the hanging zone.

As for sensors, that’s the hilarious part. The autonomous is time based with the exception of triggering the next stage. The reasons why it’s so accurate is cause we gradually accelerate and decelerate the motors, and cause we always have a fully charged battery ready. The touch sensor in the very back of the robot is used to trigger the next sequences (ramming the large balls). However, On the first photo, we added a touch sensor on that metal channel where the battery is placed. That sensor, or the “caurax” button we call it, triggers an alternate sequence in case one of our stages fail. The first photo is essentially the robot we took to states. The only things that were missing was sponsorship plates and the caurax buton.

Yep, we have. On last weekly update, I believe it mentions that we replaced the mecanums for 4" omnis in the front, and 4" tire-less traction wheels with 2 wheels on each axle in the back. Since this would cut into our pre-world reveal, I need to hold off the rationale for now, or you can see it in future weekly updates.