Revised ball holder

[Michael Kapp]

I think it might be a good idea to remove the limit switch stopping the roller and replace it with an encoder on the shaft holding the plexi so that we can easily adjust how far it lets the ball into the robot. this would be more sensitive in case the ball starts to slip, unlike our current limit switch which allows a lot of ball slippage before detecting it.

[Sunny]

So, I'm just writing this down for reflection, the next couple of days, and just so I can have this down.

Today, the meeting went relatively well. We got the wheels flipped and the robot drives better. For some reason it's definitely more "giddy" than Tanner's bot, but it helps me with just getting used to how I should approach the ball and stuff.

For those of you who saw, when we got it working towards the end, *it was working.* I was jamming the joysticks and trying to get the ball to leave the manipulator, but it just wouldn't. Towards the end though, the back bar just fell off. It was because of lack of screws on the supporting gussets. Should take max of 15 minutes to recalibrate the system and have it back running on Thursday.

I think we need a different switch. With the "big bang" towards the end, everything sorta got out of alignment. It just takes little to trip the switch, and then a lot to un-trip the switch. I think the VEX sensors are amazingly sensitive and "robust" and they would be *excellent*.

On Thursday, we can fix the parts that pulled off and redo the backing, re-adjust everything, and then drive. Since we've pretty much agreed to let the bottom bar articulate, we should probably apply that to the plan we have right now. We should pull up the goal, and just practice with it. Tanner also has the autonomous code written, so if we can give him the robot to test it, the only things that'll change come the day of the competition are some constants, (If I'm thinking of the code correctly)

On Saturday, we can apply these dimensions to Tanner's CAD and prepare pieces to mount onto the robot. We need to prepare the two double pieces of 80-20 for the front of the robot, the lower bar, the lower bar attachment, the springing system for the lower bar, and the window motor(already prepped). I think that the backing will really depend on the real robot and we will only be able to accurately tell where to put it/how when we get there on Thursday. (I think hinges best option rather than mounting the shaft with all of its bearings and what-nots.


I feel like we need a plan for Thursday. At P'tree we just "dove" into it, and things took a lot longer than expected (Or at least I expected), and this time, our Juniors won't be there, so that means we'll be losing a few key workers. I think, the first thing to do is to remove the vac system and install the roller + lower bar + window motor (45 mins). Plus another 15 minutes for tweaking and what not. So 1 hr. Then we need to wire window motor + attach backing + install switch + widen kicker (1 hr). Plus another 15 minutes for tweaking. Then another half hour to gawk at the system and thoroughly test it. So that

Makes 1 hr + 1 hr + 15 mins + 30 mins = 2 hrs 45 mins to get the system installed and running. But this is assuming we have the pieces properly made and cut before hand That leaves the rest of the day for tuning, practice, and autonomous testing.

I know that the time frame that I apply to things is under the "ideal" conditions, and they are rarely ever met, but I think it's good to have a plan. Like today, we planned to have the drive train ready in half an hour, and it was ready in just under half an hour. I've found that when we hold goals, we work faster, and the above are my goals.

- Sunny

[freds]

I missed a lot today I see.

We need a definite plan on what to build.
Kicker?

The switch is nice, but it takes some distance to release it. It was nice as it was big, robust and very adjustable. It may not have a small enough release range for how you have it aligned. If this switch is not working because something else is out of alignment, then that needs to be fixed. Just hittong a ball should not move any alignment.

Do not forget, if the front does not push a ball up to the goal agressively, the back probably will.

It also depends on where we will be playing.

'traction device' yea it is all ok until the refs change their minds. I would read the rules closely and abide.

I am very concerned on how the kicker will move through its kick.

See you Thursday. Fred

[Sunny]

We have dimensions enough to make a kicker on Thursday. If we spend the first little bit fixing the roller, then we can take the rest of the meeting to build the kicker and get dimensions.

We also think that using the bump sensors would be better than using the limit switches. They achieve the same purpose except that the bump sensors are much more robust.

If we can get a kicker setup on Logan's robot, then we can most likely just slip it onto Tanner's robot at Palmetto instead of having to fix the kicker in the morning. We can take the height and other various dimensions and create the same "setup" as Tanner's bot.

The front definitely can push the balls up to the goal. We put a couple of balls up to the rollers, and the grabber only grabs one. So if it turns out that there are multiple balls in front of the goal, it'll be better just to push them in rather than turn around and drive backwards.

<R08> ROBOT wheels, tracks, and other parts intended to provide traction on the carpet may be purchased or fabricated (“traction devices” include all parts of the ROBOT that are designed to transmit any propulsive and/or braking forces between the ROBOT and the FIELD). In no case will traction devices that damage the carpet or other playing surfaces be permitted. Traction devices shall not have surface features such as metal, sandpaper, hard plastic studs, cleats, or other attachments. Anchors (i.e. devices that are deployed/used to keep one’s ROBOT in one place and prevent if from being moved by another ROBOT) shall not use metal in contact with the carpet to “stay put.” Gaining traction by using adhesives or Velcro-like fastener material is not allowed."

The lower bar never serves as a traction device and therefore, the rule above never applies to the bar touching the ground. The refs can't just "change their mind". It's what the rules say. If they disagree, then we'll just have to convince them like we did the duct tape.

But, if we get that one ref who's having a bad day, we can take two vex omnis and bolt them to the sides of the lower bar. They are official wheels and will be beyond contestation.

- Sunny

EDIT:

@Tanner: The chassis is 7.3666" off the ground. Can I please get the distance in the middle of the chassis? Basically beating the left and right portions of the chassis?

[Michael Kapp]

On Saturday, we will likely reassemble the bottom bar using pivot gussets in place of the cube gussets, allowing us to change the angle of the bar itself as well as mount the entire bottom bar assembly such that we can rotate it with respect to the chassis. We might also use the mini-80-20 (smaller diameter) as the bottom bar so that we can get more clearance with the same height. In my opinion, we should also try to mount those 8020 rollers to the sides of the bottom bar, which will prevent any problems when traversing the 3/4" elevated section in front of the bumps.

[Sunny]

It's wonders how much clearer the mind thinks after even a little bit of sleep that it so desperately needs.

In the link below, you can see another team's roller's lower bar.

http://www.thunderchickens.org/

As you can see, the lower bar is *low*. Lower than I initially expected. The only solution I can think of now would be to move all of the wheels forward two inches so that the plates are flush up against the front and the bottom bar is sitting between the wheels. The bump creates a angle of 47.83411 degrees above the horizontal, while the back wheel would make an angle of 60 degrees above the horizontal with all of the wheels slid forward. Meaning that if we slide the wheels up.

That was our original plan, and I believe we need to revisit it in order to make this work.

Ultimately it'll all us to traverse anything, and take the articulating bottom roller out of the picture.