Unexplained intermittent CAN / 2CAN Jaguar problems at GSR

[drakesword]

Did some experimenting this weekend

We used last years robot with a 2CAN on port 1 and tested the following with 4 jags. Using code to time, we ran the robot for two minutes and printed out the total number of errors

A) 6 Conductor wires with bad routing (had a few cables wrapped around power cables)
B) 6 Conductor wires with good routing (not near power wires)
C) 2 Conductor wires with bad routing
D) 2 Conductor wires with good routing
E) 120 Ohm Termination
F) 100 Ohm Termination
G) Using PID
H) Using just voltage control
I) Having a dead battery

A C E F Had an average of 16 errors
B Had an average of 12 errors
*G Had an average of 17 errors*
H Had an average of 8 Errors
I Had an average of 29 Errors

Now an interesting trend we saw with PID marked with *
Not many errors were seen with just normal movements. We used current control first set to max at 40 Amps then set with 20 amps max. With 40 amps the robot drove without a problem. With 20 amps we had issues turning (wheels are out of alignment) but more interesting was when the robot stalled or near stalled (with 20 amps) we through MANY MANY MORE errors then if we didnt stall. So at a 20 amp stall there were more can errors. But with draws approaching 40 amps (without stalling) there were less errors.

This seems to indicate more along the lines of an issue with either the firmware on the JAG with PID and higher calculation or with the driver on the cRIO waiting for a response that cannot be returned due to said calculations . . .

Obviously with a low battery or high draws you will have more errors due to jags browning out.