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ev3dev / ev3dev-lang

(deprecated) language bindings for ev3dev sensors, motors, LEDs, etc.
GNU General Public License v2.0
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Equivalent of motor::running from earlier versions #73

Closed dsharlet closed 9 years ago

dsharlet commented 9 years ago

I've finally decided to follow through releasing the code for the project I've been working on with ev3dev, but it's now pretty seriously out of date. I've updated most of my code, but I'm stumped on something really simple: How do you tell if a motor is running or not? I see there is stop_command to get the stop command, but I don't see the equivalent of command, if that is even the right way to do this.

ddemidov commented 9 years ago

There is a state attribute, which returns a set of strings representing current motor state. So motor.state().count("running") should work as a test.

ddemidov commented 9 years ago

Also see the new tutorial here: http://www.ev3dev.org/docs/tutorials/tacho-motors/

dsharlet commented 9 years ago

Thanks, those docs are exactly what I needed.

dlech commented 9 years ago

@dsharlet, I had your ball catching robot in mind when I added the run-direct command. I'd be interested to know if you are able to make it work with other commands or if you have to use the run-direct command with your own PID as you did before.

dsharlet commented 9 years ago

Thanks for that, I was pretty happy to see run-direct in the docs! I will also try to rebuild my motor class without using my own control loop and see how far I get, I'll let you know if I can make it work. It would be great to get rid of my custom servo class.

dsharlet commented 9 years ago

@dlech, I've spent some time now updating my code. Everything seems to be working again, though I'm still using a custom controller with run_direct. I haven't been able to meet my requirements with the stock controller/API.

Here's a video that demonstrates what I'm trying to do (track a position with minimal delay): https://www.youtube.com/watch?v=vxx3bBVWaxg The video is old, but the behavior is the same today.

Here's the program used to generate that video (updated to latest ev3dev): https://github.com/dsharlet/ev3cv/blob/master/src/test/servo.cpp

I tried moving the call to "run_to_abs_pos" to outside the control loop, but the motor just stops as soon as it reaches the position setpoint and does not run again. I don't see an obvious candidate for another run command to use instead.