I tried to use pypot+vrep on a toy example (NOT poppy, only 1 cuboid, 1 motor and another Cuboid) and I am stuck with a strange behavior. It seems that python is stuck as two threads are waiting for their time.sleep(0.02) to end… In the meanwhile, I still have a connexion with Vrep, but the “streaming” between the Robot and 'Vrep` is not assured.
I do not know if I should raise an issue on github or if there is a evident error in my code attempt.
In more details.
(primary files code.zip (197.1 KB))
This is the core of code I’m running (with modified pypot so as to get the the VRepIO object and to log some functions.
# tio is the VrepIO object, toy the Robot
toy,tio = pvrep.from_vrep( config ="toy.json", scene ="VRep/toy.ttt" )
time.sleep(4)
start = time.time()
ind = 0
tio.set_motor_position( 'moteur', deg2rad(-30))
while time.time() - start < 10:
logger.debug ("one second")
logger.debug ( "tio "+str(tio.get_simulation_current_time()) )
logger.debug ( "mot="+str(tio.get_motor_position( 'moteur' )) )
logger.debug ( "mot_pos="+str(toy.moteur.present_position) )
if( ind == 2 ):
logger.debug( "set motor" )
tio.set_motor_position( 'moteur', deg2rad(30))
ind += 1
time.sleep(1)
In particular, I have modified pypot/vrep/__init__.py so that from_vrep returns the Robot and tne VrepIO
I have also logged the method make_update_loop in pypot/utils/stoppablethread.py (see below)
def make_update_loop(thread, update_func, origin):
""" Makes a run loop which calls an update function at a predefined frequency. """
logger = logging.getLogger( origin )
logger.info( "Start periodic loop at period={0}".format(thread.period))
while not thread.should_stop():
logger.debug( "inside" );
if thread.should_pause():
thread.wait_to_resume()
start = time.time()
update_func()
end = time.time()
dt = thread.period - (end - start)
logger.debug( "wait for dt={0}".format(dt) )
if dt > 0:
time.sleep(dt)
logger.debug( "end sleep" )
And I end up with the following log (the comments are added manually)
=> python vrep_toy.py
from_vrep VrepIO(vrep_host, vrep_port)
## first created thread
('create', 'SafeCompliance', 'at StoppableLoopThread')
INFO:pypot.robot.config:Instantiating motor 'moteur' id=1 direct=True offset=0.0
from_vrep VrepController(..)
## second created thread
('create', 'VrepController', 'at StoppableLoopThread')
VrepIO.start_simulation()
from_vrep _ini_vrep_streaming()
('create', 'PrimitiveManager', 'at StoppableLoopThread')
INFO:pypot.vrep.controller:update
INFO:pypot.vrep.controller:VrepController pos m=moteur p=0.0
INFO:pypot.vrep.controller:VrepController tor m=moteur t=1.2
## Both thread enter make_update_loop
DEBUG:VrepController:run
INFO:VrepController:Start periodic loop at period=0.02
DEBUG:VrepController:inside
DEBUG:PrimitiveManager:run
INFO:pypot.robot.robot:Starting robot synchronization.
INFO:PrimitiveManager:Start periodic loop at period=0.02
DEBUG:PrimitiveManager:inside
INFO:pypot.vrep.controller:update
INFO:pypot.vrep.controller:VrepController pos m=moteur p=0.0
DEBUG:pypot.primitive.manager:update with 1 motors
INFO:pypot.vrep.controller:VrepController tor m=moteur t=1.2
Both thread stuck -> streaming not assured
DEBUG:VrepController:wait for dt=0.02
DEBUG:PrimitiveManager:wait for dt=0.02
VrepIO.start_simulation()
stil I have a connection with Vrep and can change motor position “by hand”, but no streaming between Vrep and Robot
DEBUG:__main__:one second
DEBUG:__main__:tio 0.0
DEBUG:__main__:mot=-0.523598611355
DEBUG:__main__:mot_pos=0.0
DEBUG:__main__:one second
DEBUG:__main__:tio 0.0
DEBUG:__main__:mot=-0.523598611355
DEBUG:__main__:mot_pos=0.0
DEBUG:__main__:one second
DEBUG:__main__:tio 0.0
DEBUG:__main__:mot=-0.523598611355
DEBUG:__main__:mot_pos=0.0
DEBUG:__main__:set motor
DEBUG:__main__:one second
DEBUG:__main__:tio 0.0
DEBUG:__main__:mot=0.523598611355
DEBUG:__main__:mot_pos=0.0
INFO:__main__:__STOP
For info, my json file describing the Robot
{
"controllers": {
"simple_controller": {
"sync_read":true,
"attached_motors": ["moteur"],
"protocole":1,
"port":"/dev/ttyACM1"
}
},
"motorgroups":{},
"motors":{
"moteur":{
"id":1,
"orientation":"direct",
"type":"AX-12",
"offset":0.0,
"angle_limit":[-90.0, 90.0]
}
}
}
So, any advice or suggestion would be nice. Even (et même) in french :o)
Alain
When using V-REP we kind of monkey patch the time module to use V-REP time instead of your computer time. So, in theory, your code works the same way not matter how fast you can run the V-REP simulation.