Open trinidadg opened 4 years ago
Using a LegoPort
object it is possible to override the detected device. There is a similar example for how to do this with sensors at https://github.com/ev3dev/ev3dev-lang-python-demo/blob/stretch/platform/brickpi3-motor-and-sensor.py.
In your case port.set_device = 'act-l12-ev3-100'
should do the trick.
Hi, thank you for your immediate answer!
I created this scipt:
#!/usr/bin/env python3
from ev3dev2.motor import ActuonixL12100Motor, OUTPUT_C
from ev3dev2.port import LegoPort
p = LegoPort(OUTPUT_C)
p.set_device = 'act-l12-ev3-100'
motor = ActuonixL12100Motor(OUTPUT_C)
But when i run it i get this error:
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/ev3dev2/__init__.py", line 244, in _get_attribute
attribute = self._attribute_file_open( name )
File "/usr/lib/python3/dist-packages/ev3dev2/__init__.py", line 227, in _attribute_file_open
mode = stat.S_IMODE(os.stat(path)[stat.ST_MODE])
FileNotFoundError: [Errno 2] No such file or directory: '/sys/class/tacho-motor/linear9/count_per_rot'
And results in:
ev3dev2.DeviceNotFound: ActuonixL12100Motor(ev3-ports:outC) is no longer connected
Try adding a time delay between set_device
and ActuonixL12100Motor
as in the linked example.
Tried that and I keep getting the same error. Changed the time delay up to 20 seconds just in case it was being slow, but nothing.
FileNotFoundError: [Errno 2] No such file or directory: '/sys/class/tacho-motor/linear9/count_per_rot'
OK, I think this is a bug in the python library then. linear9
should probably be motor9
. You can check for sure in a SSH terminal.
$ ls /sys/class/tacho-motor/
Is the count_per_rot
attribute omitted for linear actuators? If not, it definetely looks like a library bug somehow.
It's been a long time. My memory is probably faulty :wink: Better check the docs: http://docs.ev3dev.org/projects/lego-linux-drivers/en/ev3dev-stretch/motors.html#tacho-motor-subsystem
So maybe linear
is right and the attributes are slightly different.
I suspect it is trying to cache count_per_rot
on initialization and failing because it doesn't exist... I'll take a look at this today.
It's called linear
the output for
ls /sys/class/tacho-motor/linear13/
is
address duty_cycle position speed_pid time_sp
command duty_cycle_sp position_sp speed_sp uevent
commands full_travel_count power state
count_per_m hold_pid ramp_down_sp stop_action
device max_speed ramp_up_sp stop_actions
driver_name polarity speed subsystem
so the attributes are different, but i don't know why it tries to get cout_per_rot
Yeah, the issue is here: https://github.com/ev3dev/ev3dev-lang-python/blob/ev3dev-stretch/ev3dev2/motor.py#L425
When we restructured speed unit handling we entirely missed the linear actuator case which lacks that attribute. Right now we have speed units which know how to work for rotational motors but not for linear actuators. I'm inclined to go with the simpler solution of not supporting speed units other than percentages with linear actuators; I'll implement it and we can go from there.
@trinidadg if you'd like an immediate workaround, this should work:
from ev3dev2.motor import Motor
@property
def patch_count_per_rot(self):
return 1
Motor.count_per_rot = patch_count_per_rot
And then don't try to use SpeedUnit
s other than SpeedPercent
😆 If you are also using normal rotational motors and would like them to continue working as they currently do, you can (or I can show you how to) replace return 1
with a try/catch which tries the original property and returns 1 if it doesn't work.
@trinidadg Would you be up to test out my fix from #734? If your EV3 has Internet access, you can do the following:
git clone https://github.com/ev3dev/ev3dev-lang-python.git -b fix-linear-actuators
cd ev3dev-lang-python
sudo make install
This should install the development version and you can import/use the library as normal. If you are able to test this, please do let me know how it goes! I tested to confirm normal rotational motors still work but I don't have any linear ones to try.
To undo the installation of the development version, run sudo apt-get --reinstall install python3-ev3dev2
.
The make failed with this error:
python3 setup.py install
Traceback (most recent call last):
File "setup.py", line 10, in <module>
version=git_version(),
File "/home/robot/ev3dev-lang-python/git_version.py", line 68, in git_version
raise ValueError("Cannot find the version number!")
ValueError: Cannot find the version number!
Makefile:15: recipe for target 'install' failed
make: *** [install] Error 1
Using a
LegoPort
object it is possible to override the detected device. There is a similar example for how to do this with sensors at https://github.com/ev3dev/ev3dev-lang-python-demo/blob/stretch/platform/brickpi3-motor-and-sensor.py.In your case
port.set_device = 'act-l12-ev3-100'
should do the trick.
For some reason, the instruction p.set_device = 'act-l12-ev3-100'
stopped working for me.
The output error is:
p.set_device = 'act-l12-ev3-100'
File "/usr/lib/python3/dist-packages/ev3dev2/port.py", line 140, in set_device
self._set_device = self.set_attr_string(self._set_device, 'set_device', value)
File "/usr/lib/python3/dist-packages/ev3dev2/__init__.py", line 322, in set_attr_string
return self._set_attribute(attribute, name, value)
File "/usr/lib/python3/dist-packages/ev3dev2/__init__.py", line 264, in _set_attribute
self._raise_friendly_access_error(ex, name, value)
File "/usr/lib/python3/dist-packages/ev3dev2/__init__.py", line 288, in _raise_friendly_access_error
raise driver_error
File "/usr/lib/python3/dist-packages/ev3dev2/__init__.py", line 261, in _set_attribute
attribute.write(value)
OSError: [Errno 95] Operation not supported
It worked fine for a while but now it keeps throwing that error.
Check the mode of the port. Only certain modes allow set_device
.
@trinidadg I haven't gotten a chance to look into the installation error you posted; for our purposes though you can replace line 10 (the middle line below) in setup.py
as a workaround:
setup(name='python-ev3dev2',
version='2.1.0.post3',
description='v2.x Python language bindings for ev3dev',
I've been working with ev3-dev for the past weeks and successfully configured various sensors and actuators. However I can't get the Actuonix Linear Actuator working.
When I try to initialize the class, it says the motor is not connected.
I checked for the driver and it is there:
I have changed the port and the cable just in case and had no luck.
When I create a simple Motor class in that port It uses the lego-ev3-l-motor driver. Using that it responds to the on(vel) command, going both ways and stopping on the edges. I can't use stop() (it does nothing) and when asked for position it says 0 or 1 being fully retracted or fully extended.
Really hope for some help! Thanks
Desktop :
Robot:
ev3dev-sysinfo -m output: