Motor Issues

Has anyone had any issues with motor inconsistency? We have a motor that lifts our front arm/claw. It lifts perfectly approximately 75% of the time with our redesigned robot.

Here is a video of the issue. Basically we are lifting and lowering fine then it just stops and slowly goes up. This is with the exact same pushing of the buttons: https://www.youtube.com/watch?v=zKMKsT9X1uk&feature=youtu.be

I got no YouTube at work… but we always try to keep batteries at 100% specially at matches. We have notices that with 75% of battery we start having problems lifting. (Also consider using rubber bands to help the lift (since downwards you got gravity helping you out). Also consider more torque by using a small gear connected to the motor shat and a big one to do the lifting. (The bigger the ratio between the small one on the motor and the bigger doing the actual lifting the more torque you will have lifting).

Kaverman- thank you. We have tried all those fixes, as well as swapping out motors. We didn’t have this trouble in the matches with the exact same design for the claw/arm lift. I’m not sure what is causing this. We have it geared using the smaller to larger gear, we also have 3 batteries that we charge and swap out.

Our next attempt at a fix will be this afternoon, we are swapping out brains to see if it makes a difference.

If you have time and can see the video later maybe it would help explain the issue. It lifts fine several times in a row, then doesn’t lift, then lifts fine again.

We’ve seen this type of thing, also. For us, replacing the batteries has solved the problems. There may be more going on, but I don’t know.

Steve

Sorry, just saw your post asking me to see the youtube video. (1) are you using only 1 motor to lift the arm? Maybe you should try to use to motors connected by the same shaft. Another thing you can do is use the chain kit… it comes with a huge gear that connects to a very small one and gives the motor more torque than the gear you are currently using. It only cost like $20 I think… and FULL battery.

It is very odd that it stalls for a few seconds and then recovers. I’m no expert, but it looks like the motor just doesn’t have enough power.

One thing you could try is attaching some rubber bands from the somewhere near the end of the claw, back to the main part of the robot. When the claw is extended the rubber bands will be stretched, and when it is lifted they will contract. The energy stored in the during the stretched will make the lift easier. Storing energy in a stretched rubber band is a great lesson young kids.

See attached picture for suggested placement of rubber bands. If the distance is too far for one rubber band you can tie a couple together.

(Having trouble posting the picture. Let me know if you want it and I’ll send it to you.)

elfraizer85, yesterday I was helping out another of the teams going to the worlds and he had a similar problem, but it was because he had conflicting commands on the teleop program. Try it on driver control and let me know if the error occurs to discard programming.

Thanks, we have found that switching batteries often as well as some gearing changes has helped a lot.