6724 Early Reveal

Since our team is competing this saturday (in Korea, so Friday in the U.S.?), we decided to reveal what we currently have to the VEX community.

1:1.6 4 motor mecanum drivetrain.
4 stage scissor (max. height of 45 inches), vertical slides.
2 motor utility intake (can score, de-score, and ‘stash’)
2 pneumatics-powered skyrise grabber (one on each side)

12-point autonomous (in ‘skyrise tile’ as we call it)
5-point autonomous (in ‘non-skyrise tile’)

Here is the video of the reveal;

I’ll post uploads after our first scrimmage!:smiley:

It looks pretty good. The robot in the shots from 0:04 to 0:14 have a large angled conveyor extension, but it’s missing in the shot of the robot scoring 3 cubes. Was that an older version of the robot or something?

Yes, the angled conveyor belt was a previous version; motors stalled when the cube was going through the angle, so we swapped it with a flat conveyor.

Wow that auton… I guess I need to stop hovering around my 4 pts auton and start tuning my PID loop.

I noticed that in the description it says your auton has
“Success rate:
10% (12-point)
30% (8-point)
10% (4-point)
50% (no point)”

Is this because you have to drop the skyrise section from pretty high up?

Looks like a really solid design!

Do you ever have issues with this scissor getting unbalanced? Its amazingly stable for how little cross braces it has.

That auton is scary, get it going more consistently and it will be a killer.

Definitely a robot I will be looking for more updates on, good work and good luck for this weekend :slight_smile:

The success of the autonomous depends on three variables right now;

  1. Battery voltage (the program is all time, no encoders or anything yet)
  2. Initial position
  3. Luck

Our robot can only stack 4 skyrise sections onto the base, so strong auton is a necessity.

There are only two cross braces on our robot, but one of them physically link all the motors together. We haven’t had any major problem with balance.

Have you had any problems with scissor lift stability when the robot is strafing with the lift is partially extended?

No, we used to have that problem when there was only 1 cross support linking the motors (it used to dance around), but after we added the second support we never had that problem (or negligible).

I would try to get is as close to 100% as possible. In many cases, one rock solid, consistent autonomous is much better than multiple ones that “might” work. But from what I’ve seen so far, you probably won’t have any issues making it better with some Encoders or other sensors.

Also, if the initial position makes a difference, I would highly recommend you make some sort of a jig or template to align it. It really only needs to be cardboard or something simple, but will help a lot.

Just returned from the first scrimmage. We won the whole thing! :smiley:
The 12 point autonomous didn’t work well, but the backup 3~4 pt autonomous was still enough to bring the autonomous bonus to our side.
I will be posting vids/pics as soon as I get home.

Nice job and good to hear your autonomous efforts paid off. Time to get that 12pt auton working 100% :slight_smile:

Congratulations! What percent of the matches where the winners decided by the auton bonus?

Looks like a solid robot, very nice.

I really like the pneumatic needle/plunger skyrise intake you guys have, I might need to consider something like that, it seems it could be useful for one of my ideas.

Last thing, in the video, your auton looks like it finishes with the intake hooks touching the cube which would lead to an 8 point score not 12. Am I seeing that correctly?

Yes, now that we have some time before the next competition we will really refine it to ensure decent accuracy.

Autonomous was a really important aspect of the game, especially when the robot quality are similar. Considering that the top score in this scrimmage by one alliance was around 40 points, autonomous did play a huge role in many of the matches.

The pneumatic plunger/scissor intake (scissor based on how it works) does help save a bit of time as the squeeze/release motion when trying to score the skyrise onto the base is unnecessary. In this particular scrimmage lack of drive practice and hurriedness made me miss a section or two, but otherwise it can get really accurate.

I do not have a close up for the intake, but I will post the pictures up soon.

Yes, that is true. However, I realised this immediately after filming and made the robot back off a bit after scoring, which eliminates the problem.

Hi there!
I couldn’t help but notice that you guys are from CI, I just wanted to say you are doing an amazing job with your robot! Your autonomous routines are far better than mine! Keep up the great work!

Hello, it’s really nice to hear from someone in PV!

We are competing on a tournament at Japan tomorrow (due to the lack of competition in Korea). The autonomous has been changed into a more reliable 8-point routine, and as the driver skills goes, drivers can stash 4 skyrise sections in 35 seconds.

Because everyone was busy in last two weeks preparing for this competition, I was not able to upload anything or visit forums often. Some upload will come after this competition, though, as we don’t have anything until the nationals on January.

The lift goes up nice and relatively fast…do you have the motors geared for high speed or high torque?

The motors are geared to 160RPM, and the lift goes up to its full height in 3 seconds (this may have changed a little because the robot is constantly being modified here and there). The motor attached to the vertical slide, however, has a wider range of motion than most of the other motors used in this manner, therefore requiring less torque and more speed to achieve the same effect. (I personally think that this wide range of motion gives an extra support to the scissor because the link to the motors are higher up when fully extended)

P.S. We’ve tried using 240RPM’s on the lift, which works fine with 2 cubes (2 sec lift time). However, the arms were unnecessarily fast since if the arm was raised while the base was moving towards a post, the arm would already be raised even before reaching the posts. Plus, extra torque means no motor stalls…