Robot loosing communication when switching directions

[Ether]

Originally Posted by Phalanx

Lastly, I'm wondering if direct driving Mechanum Wheels using 4 - CIMPLE Boxes wasn't enough of a mechanical reduction and hence cause too much draw.

Yes. With 6" wheels, at least 1.8x more reduction would be appropriate. For 8" wheels, make that 2.4x additional reduction.

[Greg McKaskle]

If it IS a cRIO reboot, you'll lose comm for about 1 minute,

Can you time this to see what the actual number is? And if it is close to one minute, can you give language details?

Greg McKaskle

[Al Skierkiewicz]

The loose negative power supply lead and the improper wiring for the radio are enough of a smoking gun for me. The battery will regularly drop to eight volts in a complete direction reversal. All motors are going through excessive current draw so the voltage drop across the internal resistance of the battery and the wiring and breaker feeding the PD is enough to cause this in four motor drives. The three terminal regulator is only speced to maintain output voltage down to about seven volts input. It is for this reason, the voltage regulator must be wired to the 12 volt radio output of the PD. That output will maintain voltage down to about 4.5 volts on the battery input.

[kinganu123]

I apologize for the lack of communication on my end. I actually had one of the members post this up for me and I never found the actual thread.
But yes, thanks to Mr. Reffler, we did do some troubleshooting, as he said.
Now, there ARE 3 Bane Bot Motors on the system, but I have no idea when they were ordered, but they were definitely before the 2011 season.
We are currently off of school for the week, but once we get in, I'll switch the radio over to the dedicated port and check our motors for the case short.
I'll update you guys once I can do the few tests and possible fix, now that I know where this thread is.
Thank You All Very Much For Your Help!
UPDATE
Now that I think about it, the Bane Bots Motors are the unlikely cause of the problem, because they aren't running when the radio resets itself. It's the CIM Motors that are the most probable cause.
@Ether, could you please explain to me what you mean by a 2.4X reduction? We are using 8" Mecs and I believe the ratio is 1:3 or some absurdly low number.
UPDATE
btw, to answer Mr. McKaskle's question, we do get connected back to the robot, but after a good 5 minutes. It's definitely a radio reset. Furthermore, we are using Java and running cRIO image version 28

[Mark McLeod]

Originally Posted by kinganu123

btw, to answer Mr. McKaskle's question, we do get connected back to the robot, but after a good 5 minutes. It's definitely a radio reset. Furthermore, we are using Java and running cRIO image version 28

If your radio is taking 5 minutes to reconnect to the field, then it could be that the manual switch on the back of the DLink is in the Auto position rather than Bridge.

[Joe Ross]

Have you rewired the robot since competition, or were you able to pass inspection twice with the radio wired to a PD breaker?

[kinganu123]

Originally Posted by Mark McLeod

If your radio is taking 5 minutes to reconnect to the field, then it could be that the manual switch on the back of the DLink is in the Auto position rather than Bridge.

Actually, at Brunswick Eruption, we had no connection to the networks for the first 3/4 for matches. So we did a manual override by setting it to AP and connecting the netbook to the receiver.

Originally Posted by Joe Ross

Have you rewired the robot since competition, or were you able to pass inspection twice with the radio wired to a PD breaker?

We have rewired the robot because it was atrocious, but the freshmen who were assigned to the job were told to wire it the same exact way it was before they redid it. So that could be where the problem started. But I don't recall wiring the bridge to the dedicated port in the first place.
and yes, we did pass inspection the way the radio was wired
Twice at Trenton and twice at Philly

[powellstark]

Check the power chords and the way they are fixed. There might be a loose contact and due to the movement they might be missing contact with the power and stopping its function.

[kinganu123]

sorry for not following up with you guys, but I went ahead and wired the router to the dedicated power source and it worked!
thanks a bunch guys!

[Ether]

Originally Posted by kinganu123

@Ether, could you please explain to me what you mean by a 2.4X reduction? We are using 8" Mecs and I believe the ratio is 1:3 or some absurdly low number.

I said 2.4x additional reduction.

You said in an earlier post "I'm wondering if direct driving Mechanum Wheels using 4 - CIMple Boxes wasn't enough of a mechanical reduction and hence cause too much draw".

If you are direct-driving 8" wheels with nothing but a CIMPLE box for gear reduction, your motors are overloaded. CIMPLE box provides 4.67:1 reduction. You need more gear reduction. Preferably at least 2.4x more gear reduction. So, 2.4x4.67 = 11.2 total reduction from CIM shaft to wheel.

[EricVanWyk]

Originally Posted by Ether

I said 2.4x additional reduction...

I think this should be treated as a separate issue, possibly in a separate thread. Incorrect motor reductions should be unable to cause the root issue, provided the electrical system is fine. They can definitely aggravate the issue, but they won't be the root cause. Even if the problem appears to go away after changing the reduction, it will still be lingering in the background (and harder to debug when it returns).

As many other have already said, move the radio to the dedicated radio power supply. Also, add a few things to your standard pre-flight checklist - electrical connector security, chassis fault, motor chassis fault.

[Ether]

Originally Posted by EricVanWyk

Incorrect motor reductions should be unable to cause the root issue, provided the electrical system is fine. They can definitely aggravate the issue, but they won't be the root cause.

I agree the motor reduction is not the root cause, I should have been clearer.

You still should consider changing that gear ratio though, kinganu123. PM me if you'd like some additional useful links.