paper: New Control Functions - Drive System Testing

[Ether]

Originally Posted by RufflesRidge

It doesn't describe the implementation to the detail Ether is asking about

Actually, it just says the motor controllers on CAN are disabled. It doesn't give any details at all how that is implemented.

[Thad House]

Originally Posted by Ether

Actually, it just says the motor controllers on CAN are disabled. It doesn't give any details at all how that is implemented.

I know that in the old system, in the Firmware for the jaguars, if it did not recieve a new packet for 100ms, it would shut itself off.

Also, I have heard that the PWM's don't just turn off, they actually all get set to 0 by the FPGA. I would suspect something similar happens on the CAN bus as well. It probably just sends a 0 to all motors on the bus. Easy to implement and makes sense.

[Ether]

Originally Posted by Thad House

I know that in the old system...

To be clear: having designed and implemented many fail-safe systems in my former life, I can imagine ways to accomplish this. My question is not how it might be done, but rather how it is actually implemented in the 2015 system... and where such details are documented.

[Rob Stehlik]

This is great information, thanks for sharing. 4 CIM drivetrain anyone?

[AustinSchuh]

Originally Posted by Rob Stehlik

This is great information, thanks for sharing. 4 CIM drivetrain anyone?

We will be running a 4 CIM drivetrain.

[sdcantrell56]

Originally Posted by AustinSchuh

We will be running a 4 CIM drivetrain.

Us as well

[MrForbes]

Don't know yet. Last time we played Lunacy, we had a 2 cim drivetrain

[AllenGregoryIV]

Have any BETA teams been running 6+ CIMs and experienced problems accelerating?

Has anyone managed to pop the main breaker using the new control system?

[Chris Fultz]

When we were accelerating just our robot (140 pounds), with 4 CIM, 6 CIM or 4+2 CIM, we were above 100 amps for about .4 seconds. There is not much difference in the peak for 6 or 4+2 (about 250 amps). The peak for the 4 CIM was just over 200 amps. We could run about 11 FPS, with the 4+2 approaching 12 (mini-CIMs have a higher output speed).

When we were pushing another robot (Victors in braking mode, 130 pounds but robot not active), the 4 CIM was above 100 amps for about 4 seconds, the 6 CIM for about 1.2 seconds and the 4+2 CIM was above for about 2 seconds. The recorded peaks were all in the 240 amp range. We could run about 7 - 8 FPS when pushing, so a significant loss in performance.

This is with our specific set up for the test - ~8:1 reduction and 4" wheels, so a theoretical top speed of ~12 FPS.

We never popped the main breaker, in any of our testing.

[MrRoboSteve]

Beta teams: are periods of brownout plotted in the driver station log viewer? Maybe a screen shot?

[Mark McLeod]

For Voltage Brownout the log viewer will show orange "Disconnected" dots or bars at the top, right under the Disable/Auto/Tele plot lines.



Here's a plot showing how the Disconnects for PWM stutter would look like. Basically a series of Disconnect dots two seconds apart-a second on/a second off/a second on/etc.

[MrRoboSteve]

Hmmm. So is it possible to distinguish from actual connectivity issues? I'm thinking about the troubleshooting procedure here:

http://wpilib.screenstepslive.com/s/...og-file-viewer

Would hope that it's not bundled with one of the other "major events" (key 10 in first image)

[Mark McLeod]

Originally Posted by MrRoboSteve

Hmmm. So is it possible to distinguish from actual connectivity issues? I'm thinking about the troubleshooting procedure here:

http://wpilib.screenstepslive.com/s/...og-file-viewer

Would hope that it's not bundled with one of the other "major events" (key 10 in first image)

It can be distinguished from other Disconnect events in that data is still being received from the robot. There are no vertical orange bars showing where data from the robot is totally missing.
Other Disconnect events, e.g., loss of robot power, will also show a blank for all the other robot readings (battery voltage, robot CPU %, etc.).

[Oblarg]

Originally Posted by MrForbes

Don't know yet. Last time we played Lunacy, we had a 2 cim drivetrain

We had a 0-CIM drive train in lunacy.

[Thad House]

So I went and found our logs from IRI. This was a 100lb robot geared for 15.9 FPS.




Sorry about the giant picture im trying to figure out how to shrink it.