Router browns out with multiple CIMS driving WCD

[Chris Mounts]

We're running a similar setup. We've got the 8" pneumatic wheels, WCD gear boxes with the same gear ratio (I think), 3 CIMs each side, and a 1/8" drop. The only difference is our C/C of wheels is about 7.9". We're driving and turning without an issue. I'm sure the larger C/C distance isn't helping but I wouldn't think it would cause consistent brown outs though.

Can you compress the C/C distance?

Not sure about the current. Never checked on blocks.

[Bob Steele]

We are using 8 6" pneumatic wheels and 6 CIMs and are using a 3/16" drop this year because of the pneumatic wheels.

You might also take a look at what pressure you are using in your tires.
Higher pressures would probably help with scrubbing.

We are also current limiting in the program to maintain voltage to the RoboRio.

[Tiago_MARS]

Well we found out through the VRM that it is in fact not the radio but the RoboRIO that is browning out. There isn't a very easy way to change the drop or the C/C without redoing the entire chassis and I don't think that would be necessary since it had already worked earlier in the week.

[PayneTrain]

Originally Posted by Bob Steele

We are using 8 6" pneumatic wheels and 6 CIMs and are using a 3/16" drop this year because of the pneumatic wheels.

You might also take a look at what pressure you are using in your tires.
Higher pressures would probably help with scrubbing.

We are also current limiting in the program to maintain voltage to the RoboRio.

We've been running 3/16 and a high difference in pressure between the center and outer wheels and we have been pretty good. One of these changes is easy and the other probably is not.

[Ether]

Originally Posted by PayneTrain

high difference in pressure between the center and outer wheels

difference in what direction?

[Chris Hapstack]

Originally Posted by Ether

difference in what direction?

I think the trend has been over-inflating the center wheels and under-inflating the front & back wheels, which kind of adds to the drop center effect. But of course I can't answer for 422.

[Tiago_MARS]

Fix! Well that was interesting. There was a fault in the PD board (orange light) so once we cleared it it seems to work as expected. Thanks to everybody though!

[PayneTrain]

Originally Posted by Chris Hapstack

I think the trend has been over-inflating the center wheels and under-inflating the front & back wheels, which kind of adds to the drop center effect. But of course I can't answer for 422.

Yeah you got it.

I posted that while eating at the shop today and frankly I'm surprised I completed sentences...

[Greg McKaskle]

There was a fault in the PD board (orange light) so once we cleared it it seems to work as expected.

A sticky fault on the PD is there to catch your attention to something that happened some time ago. I do not believe it affects the current usage or roboRIO brownout prevention. I suspect that other things changed as well, such as changing out the battery, and perhaps even some wiring or mechanical changes.

So the problem wasn't fixed by clearing the sticky fault. You may have a weak battery in your midst that will reintroduce the problem another day. You may also have some binding or electrical connection issues that are inconsistent and may reintroduce the issue.

So, please experiment and look for the issue. Also, be sure to open the DS log file viewer. You can click on the gear on the DS and open the viewer. Look at those logs and compare to others. If you don't see the issue, please post the file or a picture of the viewer.

The other day, the robot was pulling a bit while the drivers were testing it out. The programmers opened up the log viewer and clicked to see the motor currents while others started feeling motors and tracing wires. Sure enough, one drive motor was disconnected. Guess which team found the issue first?

My point is that the log file has valuable info and can help identify many issues.
Greg McKaskle

[Joe Johnson]

All closely related threads:

Power draw issues


Battery Voltage problem

Voltage Drop issues


Robot loses communication while going over obstacles


Router browns out with multiple CIMS driving WCD