Issues when chaining multiple driving actions

Hello,

I am currently working on a university project involving Cozmo. We are implementing lane-tracking/autonomous driving. Every time Cozmo's camera receives a new frame, different analyzing steps are made to decide where he should drive. When it is detected that he is about to face a cross road, he is supposed to drive straight for a given amount, then turn left. As long as there is no crossing, Cozmo is driving using the robot.drive_wheel_motors function, which works fine. Here is our code:

# Registering the camera handler
    robot_obj.add_event_handler(cozmo.world.EvtNewCameraImage, lane_tracking_obj.process_frame)

Within the process_frame method the following code is executed:

[...]
if not RobotStatusController.is_at_crossing:

    crossing_type = CrossingTypeIdentifier.analyze_frame(bin_img)
    self.navigator_controller.handle_crossing(crossing_type)

[...]

Where as handle_crossing is simply calling the following method:

def turn_next_left(self):
        RobotStatusController.is_at_crossing = True
        self.robot.stop_all_motors()
        self.robot.drive_straight(util.distance_mm(80), util.speed_mmps(Settings.cozmo_drive_speed)).wait_for_completed()
        self.robot.turn_in_place(util.degrees(90)).wait_for_completed()
        RobotStatusController.is_at_crossing = False

We are prompted with the following exception:

/home/void/Documents/Projects/CozmoPSE/gruppe4-cozmo/Engines/RobotController/DriveController.py:25: RuntimeWarning: coroutine 'Action.wait_for_completed' was never awaited
  self.robot.drive_straight(util.distance_mm(80), util.speed_mmps(Settings.cozmo_drive_speed)).wait_for_completed()
Task exception was never retrieved
future: <Task finished coro=<Dispatcher._dispatch_event() done, defined at /home/void/.local/share/virtualenvs/gruppe4-cozmo-rndZJdD9/lib/python3.7/site-packages/cozmo/event.py:415> exception=RobotBusy('Robot is already performing 1 action(s) <DriveStraight state=action_running distance=<Distance 80.00 mm (3.15 inches)> speed=<Speed 70.00 mmps> should_play_anim=True>')>
Traceback (most recent call last):
  File "/home/void/.local/share/virtualenvs/gruppe4-cozmo-rndZJdD9/lib/python3.7/site-packages/cozmo/event.py", line 426, in _dispatch_event
    result = event._dispatch_to_func(handler.f)
  File "/home/void/.local/share/virtualenvs/gruppe4-cozmo-rndZJdD9/lib/python3.7/site-packages/cozmo/event.py", line 210, in _dispatch_to_func
    return f(self, **self._params())
  File "/home/void/Documents/Projects/CozmoPSE/gruppe4-cozmo/Engines/LaneTracking/LaneTrackingEngine.py", line 66, in process_frame
    self.navigator_controller.handle_crossing(crossing_type)
  File "/home/void/Documents/Projects/CozmoPSE/gruppe4-cozmo/Engines/RobotController/NavigatorController.py", line 19, in handle_crossing
    self.drive_controller.turn_next_left() # ToDo Change Direction
  File "/home/void/Documents/Projects/CozmoPSE/gruppe4-cozmo/Engines/RobotController/DriveController.py", line 26, in turn_next_left
    self.robot.turn_in_place(util.degrees(90)).wait_for_completed()
  File "/home/void/.local/share/virtualenvs/gruppe4-cozmo-rndZJdD9/lib/python3.7/site-packages/cozmo/robot.py", line 2173, in turn_in_place
    num_retries=num_retries)
  File "/home/void/.local/share/virtualenvs/gruppe4-cozmo-rndZJdD9/lib/python3.7/site-packages/cozmo/action.py", line 553, in _send_single_action
    (len(self._in_progress), action))
cozmo.exceptions.RobotBusy: Robot is already performing 1 action(s) <DriveStraight state=action_running distance=<Distance 80.00 mm (3.15 inches)> speed=<Speed 70.00 mmps> should_play_anim=True>

We are wondering why this happens, mainly because the example scripts 02_drive_and_turn.py is doing pretty much the same thing. Isn't cozmo supposed to wait until the drive_straight routine finished executing before he is starting to do the turn_in_place ?

Furthermore we are wondering if we are using the event system as it is supposed to be used? Are we missing something?

EDIT1: After further investigation (we logged all action & behavior events) we managed to find out that turn_in_place fails with the following failure reason:

Action Stopped: <TurnInPlace state=action_failed angle=<Angle 1.57 radians (90.00 degrees)>, speed=None, accel=None, tolerance=None is_absolute=False failure_reason='Action failed due to tracks locked' failure_code=tracks_locked result=ActionResults.TRACKS_LOCKED>

This is really surprising because we are not performing any action on this track beforehand.

anki / cozmo-python-sdk

Issues when chaining multiple driving actions #206