DR4B Extending Reverse Stacker (V2)

I’m assuming you are referring to the ITZ-style fourbar mechanisms where the intake moves in and out of the robot. That’s a fairly good solution I suppose, but would you have enough motors? a one motor four bar may not be smart when lifting 5lbs, especially if it’s mounted on the lift.

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I think something similar to a mobile goal mechanism might be more feasible. the 4b could intake the cubes into the robot where the passive stacker could do its work, and when its ready to outtake, it can release the cubes from the passive mech and allow the mobile goal mech to outtake into the zones.

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4 motor base
2 motor DR4B
2 motor differential powering four bar and claw (this will be hard do though)

or

1 motor four bar
1 motor claw

or

change the base to something that can use two motors.

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DR4B will, probably, be a meta design this year, but using strings to keep cubes in the stack…

Please, give me a break. One good bump from an opponent defense bot and half of the cubes will fall to the floor.

On the other hand, if there is more rigid structure holding the cubes in the stack, then this design could work.

For example, you can use metal or plexiglas angles attached in the telescopic manner (like a slider on the linear lift) to keep the cubes in a nice straight stack. Once you extend those aligners for the first time they could stay locked in the tall configuration.

Cube alignment before intaking is another concern. But you can always add a bracket for passive alignment, or even make it active roller assisted, which could retract back into the robot when you are ready to deploy the stack into the goal zone. Single motor could easily do those two functions with ratchets.

The center of gravity is, probably, the least of concerns - just add enough metal on the back and enjoy pushing power of 4 V5 motors to play defense on your opponents. :smile:

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My impression is that the string isn’t meant to act as side guards to prevent cubes from falling, but rather apply force to compress the cubes together, increasing their static friction. I don’t know whether or not this will be enough, as I don’t yet have access to an actual cube, but depending on the surface it could be viable.

On the other hand, if an opponent hits the stack directly you are right, no amount of friction is gonna save that stack. If this were more centered in the bot it would work much better, as the stack would be protected, but of course depositing becomes much more difficult there.

I really like the concept and I think it could certainly be adapted to work in reality with enough effort

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how do you figure this. the video showed stacks much taller than that. please explain yourself

One big problem that I (don’t think) anyone has touched on yet is the limit of how a rubber band can be stretched. It could easily snap after just a few cubes. I suggest a gravity powered collapsing shell, which expands as cubes are added. You also probably want an easier method of intake (ie: less precision needed).

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The rubber band could snap and the right but would be prone to tipping. The video is an animation that looked as if it was made in blender (very well, though.)

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My apologies if someone has already said this but I can only imagine how hard it would be to deal with defense and a high internal stack like that. Unless the string is strung extremely tight all it takes is a bump for the cubes to go everywhere out of the stack. But great job with such an early animation, I can’t wait to see from you late season.

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One thought on this would be to look at using a v5 motor to provide some counter tension instead of rubber bands. The code would use v5 current and torque sense to retract rope as needed and provide static tension. I would be worried about overheating though.

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Again, an awesome concept and an amazing animation. A thought - I wonder if you could use the tension from the strings to pull as a counter balancing force as the stack gets heavier and taller?

There’s a lot of people picking at this design, some constructively others less so - remember haters gonna hate.

The 3 most worrying problems I see are 1) Tipping with a heavy load 2) Stack being knocked over by defensive bumping. 3) The string getting tangled if the stack is knocked over.

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That. Looks. Awesome. I want it.

I really like the design and the animation(how did you animate this). I feel like there will be a limitation on the number of cubes you can grab though based off of the center of gravity more than lifting strength.

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weight is a factor, friction is a factor, even tho they are being held down it would be very hard to pick all that up and be stable.

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One thing that could help is to have 2 strings on each side instead of one.

I think a better idea might be to have wide non-slip mesh instead of string.

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I would use a rigid extender from metal or polycarb. Strength isn’t really a problem, any rigid material would work.

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How would this extend vertically, slides?
EDIT: I mean the rigid version

Yeah slides… or something…

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Or maybe just like a mini little polycarbonate passive scissor lift using rubber bands to pull it down on the sides.