Brainstorming Ideas for grabbing mobile goal and 20pt zone

Vex U participant here.

Here’s what going on my mind:
Let say I have 10 cones on my mobile goal that’s on the base of my robot. How will the cones react when I cross the bar/tube that separates the 5pt zone and the 10 pt zone? What kind of mechanism can be effective to grab the mobile goal and place it on the 20 pt zone? What are the pros and cons?

Here’s a sketch of an idea I started out but nothing concrete.

The base of the robot has a type of downward pneumatic claw that grabs the mobile goal, drive backwards, and let it drop over the bar that divides the 10 pt zone and 20 pt zone. My worry is that if the back of the robot gets heavy with 10+ cones, it will affect the center of rotation of the robot. Also, when I cross the bar, it’ll tilt the robot by maybe 1-2 degrees and could affect the stability of cones on top of the mobile goal.

Does this idea has potential? What are your thoughts? Any other ideas?

@Yerayrobotics this was my teams plan, however you have to consider that you’ll have to lift the mobile goal, as its base wont start at that high of a point, i’ve done the calculations and a 2 motor 1:7 4 bar @ 7.5 inches from the fulcrum has more than enough strength to lift and drop the goal

Great minds think alike, right :slight_smile:

Based on the tests done in some of the other forum threads, it seems like a 2 some inch bump shouldn’t affect the cones; depending on how many you have. I’m planning on around 10 for each mobile goal max and I believe someone said that dropping the bases from about 2 feet resulted in cones above 6 popping off but transitioning down to about 2 inches should greatly help with that, i would think. I don’t have game objects yet so it’s purely hypothetical but…


I know the mobile goals have a bit of a rim type thing on the edge that’s a little bit above the ground. Maybe a rotating thing that goes under it and is then pulled up by a piston on each side???

@Joseph W(182 C) i was thinking something more along the lines of a claw, with the fulcrum at the center, wraps around in the ~1" lip type thing, so that when you open it, it gets spit out from the force of it opening, let me draw a sketch real quick

Edit:not an artist so sorry :confused:
green=claw part
pink= mobile goals
red= support structure
blue=pneumatic pistons

I’m thinking of something like what I attached below in sketch. The “claw” is low enough to reach under the edges of the mobile goals and when the pistons start receiving air, the claw closes into the second position. Hopefully, it’ll get the height needed to pass over the 2.38" bar and drop the mobile goal to the 20 pt zone.

True true :slight_smile:

Hopefully, crossing the 1.15" bar (the small one) won’t affect the stability of the cones on the mobile goal. My fear is crossing the bar and cones start to lean to one side. Maybe having the wheels separated helps.

Forgot my sketch lol.

Now that I think about it, I must be mindful of the pistons. They’ll be holding the mobile goal along with the cones for a good while. I’ll need to check if they hold around 5-7lbs.
Sketch (1)2.png

@Yerayrobotics yeah, that seems like it’ll work, however are yiu worried at all about that 4 lbs situated along your back two motors? Rather than spread throughout your 4 drives?

I’m actually considering a 8 motor drive because of that situation. It would be dangerous with just two back. I’ll have 4 motors left to play with the lift and intake.

@Yerayrobotics oh yeah, your vexU, anyways, im going with a pneumatic top claw style intake, it generally holds them with no air pressure, and im devoting 2 to a rd4b, and 2 to a chain bar, to get them onto the stack rather than just high up

@9065_parker Isn’t that similar to Team 62 from Skyrise except with a pneumatic intake?

@Yerayrobotics yeah, i just went and watched it and that almost exactly what i’m going for :confused:

That’s like my exact same design as well :stuck_out_tongue:
Except for the mobile base picker-upper. Internal stackers all the way!

As for your sketch earlier, do you have a plan to get the base off the ground? I’m personally probably going to stick to my original design as it allows the base to get off the ground; unless there’s a simple way to get your claw design off the ground??? B/c i REALLY like the idea of forcing the base out like that and the extra control it gives. :slight_smile:

As many have said, same exact idea. As long as you can get the ground clearance it shouldn’t be a problem. I wouldn’t doubt we have the same idea for stacking the cones either.

@Joseph W(182 C) i already have motors allocated to doing a 1:5 like amll 4 bar just to lift off the ground, also, i think you misunderstood me, im totally doing internal stacker

@Yerayrobotics The base can be grabbed up by the upper sides too. I wonder if you have enough room for your fulcrum in the case of grabbing up top versus on the bottom. Look at Fred 4 from long ago.

@Team80_Giraffes Can you help me a bit pinpoint what are the upper sides? I’m not sure if there’s another area where I can get a good grip of the object besides the bottom next to the black part.

Maybe you meant these?

I don’t have extra motors sooo :stuck_out_tongue:
That’s still a really good idea though.
I know your doing an internal stacker, I’m sorry if I worded my post in a wierd way :slight_smile:

Exactly. Where you have the blue arrows. Nestle in there to lift is a possibility versus here you have the magenta arrows below. The cone should not come down to interfere with the blue arrow area.

Ehhh idk about that. Less grip and it has to be in the proper orientation to grab. The bottom will probably be best.

So being able to score on a mobile goal inside your robot requires two stages of a lift: one to move the cone above the mobile goal and one to lift the second stage up and down. The most popular way I’ve seen is by using a linear lift such as linear slides on the first stage and a chain bar on the second stage. Would it be possible to complete the tasks by using one stage or by conjoining both stages?

I’ve thought about this, and I don’t think so.
When stacking from the ground onto an internal stack, you need to move the cone forwards and backwards(I’ll call it the X axis), as well as up and down (the Z axis).
Obviously, the X distance you need to move remains constant, but the Z distance would need to change as your stack grows. This means that the path that the end of your lift needs to take to stack would change as you stack more cones on your internal stack.
To change the path of your lift, you would need to somehow change the geometry of your lift over the course of the match, which would require more motors and an extremely complicated lift mechanism and therefore offers no advantages over a 2 stage system.

That, or you could always lift to full height (or wherever the lifted cone is right over the stack) and drop it, but that opens up a whole new can of worms.