Chief Delphi - Robot losing and regaining drive power

Quote:

Originally Posted by PSHRobotics (Post 1056163)

So would that mean that a mechanical or electrical problem would be causing the jags to stall and its not specifically the jags? And we are not using CAN but I agree with your analysis that it would most likely not make a difference.
Would a circuitry problem with one jag cause there to be problems for the other jag? If there is some movement from a specific side when the robot is not "responding" it is only at the very moment the joystick is pushed forward. Most of the "driveless state" the robot is stationary and it does not appear to be attempting to move (not fully sure).

If you are in fact getting over current faults on the Jags (all signs point to that), the real problem is a motor stall drawing too much current. The Jag detecting this fault and waiting (stopping) is a symptom (3 sec may be a little long to wait but that is not the point). If the Jag didn't stop drawing that much current, the problem would move up the line and the breaker would likely trip (again symptom not problem).

As for one jag fault causing the other fault, there is a cascading effect as Kevin described. Since motor load is the problem, when one faults more load is placed on the other causing a fault.

Quote:

Originally Posted by PSHRobotics (Post 1056163)

How can we check if the problem is a digitical sidecard power short? And if it is for directional data, would we still see the problems moving forward?
I do believe that forward is the jags in reverse, so it is possible what you're saying is absolutely correct. So if the jag is having this problem moving in the reverse direction, how would we know that it is having a fault? I know it does not do this without load, which from the previous posts seems to show that it isn't a problem with the/a jag going in a specific direction.

The digital sidecar has green 3 LEDs labeled with different voltages. If one of them is off you probably have a short. The difference between a forward and reverse PWM signal is just a difference in pulse time so the sidecar is not the problem there.

Again I just suggested the possibility of the a Jag being bad in one direction, it is very unlikely. It is most likely a mechanical issue. Now that you say that you are only driving the center wheel on a 6wd, CG may be the reason it is directional (I didn't diagram it but it seems to make sense at first glance).

Are you using Black Jags or Grey Jags?

If you are using Grey Jags the fault LED sequence is an alternating color blink.
If you are using Black Jags the fault LED sequence is slow red blink (not to be confused with fast red blink, which is partial power reverse). Also, if you have Black Jags you can test one and monitor the current using BDC-COMM on a laptop (most teams using CAN have the supplies for this). Of course Kevin's clamp on ammeter is a little easier to use.

I trust Kevin will get you all diagnosed and working toward a solution. If you have any other problems, Team 365's MOEbile Pit will be happy to help (we are also in Curie). I will be at championship Thursday probably after 9AM (flight gets in at 7:50). Look me up especially if you do have an weird one-sided Jag (I would be happy to look at it in BDC-Comm for you and TI people would probably like to look at it too).