[FTC]: FMS Dropping only the joystick possibly?

Hello everyone,

Yesterday my team went to the GA Tournament and boy we had a blast. We took 1st place for like 5 minutes, but it was great. We eventually lost in quarterfinals.

I would like to Thank the entire volunteer crew at GA, Mr. Lowe, and SPSU for helping out in the event.

One thing I noticed, and so did a few other teams, was that the FMS seemed to drop the joysticks, but not the buttons. One example is in our match 4, I, the driver, had no control over the wheels, and the manipulator controller, had no control over the arm, which were both controlled by joysticks. But, the manipulator controller had control over the puck rack emptier, which was controlled by a button. When the match ended, the crew had us push buttons to ensure that the controllers were still connected, and they recognized the buttons.

Now I don’t want a start a verbal bashing against the FMS, but I just wanted to know if any other teams had issues where their joysticks would not function, but then when checked with the FMS, the buttons still worked.

Nothing quite like what you’re describing popped up at Vegas this weekend, but several similar FMS issues did. (We had the reverse happen to us; our button-controlled servos would randomly not respond near the end of the day, but we suspect a short in our servo cable rather than any field problems.)

I don’t know exactly what causes these errors, but my team discovered that keeping the batteries fully charged and power-cycling the NXT between matches keeps weird control issues to a minimum. Also, are you positive it was the FMS? Do you have things that were hooked up to both joysticks and buttons, and that would only respond to the buttons in those cases? If not, I’d check your wires and motor/servo controllers.

Well, the part with the button relied solely on the button for motion. I’m not sure why my joysticks would time out.

And the strange part is that I’ve run that code against the FMS available online multiple times, and have never had this issue occur…

Tell us what motors and motor controller were controlled by the joystick and what were controlled by buttons.

The drive motors and the arm motors were controlled by the joysticks and I had one servo controlled with a button, it would flip positions when the button was hit.

We’ve had issues with motor controllers locking up which can only be reset by cycling the 12V power. I don’t know if we have ever had the servos work when then motors locked up or not. We have had the servos lock up and the 12v motors work. The way we know this is because the NXT is still running fine and we can control Lego motors that don’t have motor controllers. Also we can cycle the 12V power and regain control.

It’s my personal opinion that Bluetooth and the FMS get blamed for a lot of problems that are caused by the motor controllers.

That sounds about right; the motor controller issue is a known reason for problems like this and the FMS, if it did malfunction, would most likely affect the entire robot.

As a side note, the last time our motor controllers locked up our servos were also unresponsive. I have a feeling that it might depend on where the servos are in the motor controller chain (ours are in the middle).

I appreciate the analysis. Thanks. It’s pretty cold comfort, though, since there is really no fix for it.

…I think I might have…

Could enabling the PID Loop during Teleop cause that problem of dropped control or motors running without joystick commands?