More Efficient Physical Limit

VEX V5 General Discussion General Forum
#1

I personally have never had luck with 4 bars on the front of my lift this season and am currently using a chain bar. The only issue is the chain bar needs a physical limit to stop it. My current design, I fear, will cause the shaft powered by the motor to bend and my previous design with zip ties is too clunky and when the chain bar is lifted up the zip ties are in the way of the cone. My question is does anyone know an efficient way to solve my problem that is not bulky like my current design. Thanks
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#2

Limit switch to stop motor?

#3

I just use a mesh. It’s soft and it doesn’t break anything.

#4

Have you had any problems with the mesh breaking or do you have it triple wrapped to avoid it? I will probably use this for my robot it’s a great idea.

#5

Yes it is reinforced. Every two weeks I replace it. Other than that, it works great! :slight_smile:

#6

I use a shaft encoder and check to make sure the arm hasn’t passed a certain point.

#7

I’m not very good at coding but I tried telling the motor to stop once it measured a certain distance but it would keep moving due to momentum and gravity.

#8

You need a p controller

#9

I know a bit about PID and how it works but I don’t know how to make a P controller. If you could help or point me somewhere thanks.

#10

https://vexforum.com/t/simple-p-controller-for-arm-position/23699/1
That should do it

#11

A couple of rubber bands could help slow it down before it hits any mechanical stop, and would help it lift faster.

#12

That makes no sense
How do bands meant to help lift that increase your speed slow you down?

#13

Increases speed going up, slows down going down.

#14

We have rubber bands they were just disconnected from the arm when I took the picture. The main issue with my mechanical stopper is the size of it. I could always just cut it with my dremel but I was wondering if there was a better option. I’ll probably try the P controller but I prefer mechanical options because I’m not good with coding

#15