Best simple lifting mechanism: rotating joint or elevator?

Also: while I’m sure you’ve found lots of really good tutorials online for cascade lifts (if you go against my advice and do that), but I have a couple of pictures of a simpler design for one, although it may or may not cost more on your budget sheet.
But just stick with your 4-Bar and let me know if you decide to do otherwise and I’ll see if I can find the pictures.

2 Likes

I think, @Got_a_Screw_Loose is correct: 4-bar is the best choice here and it could be made very light if you replace top portion of the bar with string or chain.

Another consideration would be custom claw that could be made lighter than the stock vex claw and still be able to grab multiple game objects. But this could be tricky to build for a novice…

I will certainly would love to take on the challenge of building the lightest possible clawbot that could accomplish those tasks.

5 Likes

Nah, I’d advise against this. Especially in stacking games such as the small scale one described. The ball collection though, maybe.

1 Like

I think you could just have a single vertical bar with a chain running all the way around it, and attach a claw to the chain. If there is no initial size limit, this could be a good option.

If your looking for easy to build go with rotating, if your looking for originality go for elevator

Part of the issue with building elevators and scissor-lifts is experience. You need to have a lot of knowledge about making solid screw joints and eliminating friction between the bars or chains, just to make sure the motors can even begin to handle the weight. I know that for this year, many teams at my school have done some pretty solid one-sided 6-bar linkages to do this year’s challenge, which isn’t particularly crazy for lifts. I’ll post a diagram of them, if you want.

In my opinion, it would be beneficial for you and your team(s) to build a basic 4-bar and get some experience working with pivots, friction, design efficacy, and principles of torque. If you ever get into competition, these are priceless skills to have.
Note: I haven’t read your criteria/constraints yet because my school computer won’t let me…I’ll edit when I get the chance to see them.

1 Like

To elaborate on my suggestion earlier.

Here is an example, just don’t do it as big.

1 Like

Initially, I thought that too, but once I learned more about specific constraints, I changed my mind.

There are a lot of differences from what we usually do in VRC. For example, game objects for this challenge are very light and you don’t need as large range of motion as most of the VRC games require.

On the other hand, each part adds virtual cost that later will be subtracted from your total score (I am not 100% sure what is the exact formula). Also team doesn’t have access to some common parts, there is very little build time left, and both practice time and extra programming might be an issue.

Initially, I suggested 4-bar lift, but it would be tricky to do block stacking with it. Because, first, you would need to either balance it very well with elastics or program PID hold to stay at certain height automatically. And, second, the end manipulator will travel in arc path, which would require extra experience driving it.

If it was a VRC challenge, with no game object possession limit, the best strategy may have been to accumulate stack of the cubes inside the robot, adding the next cube from the below, and then deposit entire stack at once. That would call for a design similar to Team 1103 Currahee from the RoundUp, but then there is likely not enough time and skills to build and debug something like that.

My understanding is that design has to be as simple as possible to drive and build with as few fancy or custom parts and preferably without any advanced programming.

A claw attached to the rack bracket going up and down along the linear slide rail might be the easiest thing to build. However, from the cost perspective rack gears with the mounting screws might be more expensive than just dropping chain along the rail and using a sprocket instead of a gear.

If anyone wants to take a look at the detailed list of constraints, and could spend a few hours building and testing a prototype, @grlygrl28 could add you to PM discussion.

2 Likes

this information is still relevant?