So my team has an 8 bar lift with a 7 to 1 and high speed motors. We have competed before with this set-up without problems. Our lift all of a sudden started to stop. And stop quickly. We have changed the motors, motor controllers, and the amount of rubber bands. We dont have any idea what the problem is and we were hoping some other team had any idea how what the problem might be.
Video: - YouTube
How many motors?
6 motor lift.
Seems like the motors are twitching, can you post your code?
Too many rubber bands, the lift is stalling out.
My socks are ready.
code.zip (3.88 KB)
One of our teams had a weird twitching similar to what is in the video. We tried lots of different things (Re-download Code, Check Motors, etc.), but couldn’t get rid of it. Finally, we tried a different cortex and had no problems after that.
We have tried a new, straight out of the box, cortex. We have have also removed some rubber bands but still can’t seem to fix the issue.
We have had this problem. If there are two buttons/functions both setting the motors to different values, then the motors will go back and forth between the two settings. For example, if Btn 5U is not pressed, then run motors at 0, but if Btn 5D is pressed, then run motors at -127. When you press Btn 5D, both conditions are met, setting the motors to both 0 and -127. The fix is to put the 5D section into an else if statement below your 5U section.
I think this is an excellent suggestion to look at. The twitchy behavior smells of conflicting code commands. I was going to ask if this was under driver control or what. Look at your driver code.
If you can, I recommend oulling the shafts from the motors and taking off the rubber bands. See how smooth it is there. Then, replace the rubber bands. Is the force consistent all the way through lifting? (Gets harder and harder to lower the farther you go) With improper rubber band geometry you can run into problems where the lift kind of fights itself. It’s a bit hard to explain but essentially the components of force don’t match up and a ton of pressure is put on joints that create friction. Granted, I doubt this is the case in this scenario.
If neither that nor testing the code fixes it, test each motor to ensure they are all speed. If one is torque, you could get this behavior.
We had the exact same thing. check the code for this.
code looks pretty good, but TeddyBear.h !
Who doesn’t want to include a Teddy Bear? Sometimes, you just need to hug something. VEX parts are so cold.
I know, it just made me laugh, the code came from here. I’m sure I gave it a much less cuddly name.
I have a lot of default mappings for @jpearman. “Cuddly” doesn’t make the list.
Ok, I now have another item to add to my VRC bucket list.
Before I graduate, I’m going to use one of those giant teddy bears as a legal nonfunctional decoration.
There were some teams at our last competition that had different Pokémon on their lifts.
Looking through your code it looks like you don’t have a wait command at the end of your user control task. Maybe it’s going through the code too fast? Try adding a wait1Msec(20); at the end of your user control and see if that helps.
Just updating… I’m not sure what they did but I think they fixed it and they’re socks were ready for the competition (even though I wasn’t there to see). There was a lot of stuff in that code…
More detailed update may or may not be coming soon for future reference.
That was fast: