View Single Post
  #23   Spotlight this post!  
Unread 20-05-2016, 09:32
maxnz's Avatar
maxnz maxnz is offline
Registered User
AKA: Max Narvaez
FRC #2855 (BEASTBot)
Team Role: Student
 
Join Date: Jan 2016
Rookie Year: 2016
Location: St. Paul, MN
Posts: 247
maxnz is a glorious beacon of lightmaxnz is a glorious beacon of lightmaxnz is a glorious beacon of lightmaxnz is a glorious beacon of lightmaxnz is a glorious beacon of lightmaxnz is a glorious beacon of light
Re: Weird Gearbox Sound

Quote:
Originally Posted by cbale2000 View Post
So, a few thoughts based on experience:
  1. The first part of the video seemed like an electrical issue, like a dead battery or a short. The behavior was not indicative of a mechanical failure, at least none I've seen.
  2. The sounds in the second part sounds like one of three things, it could be either one of the motors not being powered (assuming you use 2 per gearbox), a CIM that has lost it's key between the shaft and the pinion gear (and is free-spinning), or gears not engaging each other in the gearbox for some reason (probably due to lost teeth or loose motors).

I would be curious if the issue persists if the robot is up on blocks (wheels not touching anything), I would also be curious if you could identify a certain action that causes the issue to happen consistently (turning the robot, for example) or if it just happens at random. I would also suggest monitoring battery voltage during such tests through the driver station.


On a somewhat related note, our team experienced some odd behavior (seemingly random jerkiness during acceleration) with our drive system this year when using Talon SRX controllers in CAN configuration. We later realized the issue only occurred when the controllers were fed a 100% power command. We changed the code to limit the max output to 99.9999% power and the issue vanished.
The first part was the battery. It hasn't done that when we used it with a full battery since then.

When we recorded those sounds, we were lifting up each side individually and ran them, first the left (first sound), then the right (second sound).

I'll make sure that we (I) clean out and regrease the gearboxes tonight. I'll also check the CIM motors to see if they still have their keys. What do you recommend to clean the parts with (paper towels, something else)?
__________________
As a senior that will be leaving the team, I have to teach others how to:
1. Know the manual extremely well
2. Wire the robot
3. Organize the shop
4. Help people find parts when they need them
5. Find parts to order and give the detailed list to the coach in charge of buying the parts
6. Keep track of team updates, Q & A responses and FIRST blog posts
7. Be active on CD
8. Plan and execute drive team strategy
And more that won't fit on this list...
Reply With Quote