Bug in Armature actuator

[skadge]

Using this armature, MORSE crashes with the following error:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/morse/blender/calling.py", line 54, in sensor_action
    component_action(contr)
  File "/usr/lib/python3/dist-packages/morse/blender/calling.py", line 50, in component_action
    cmpt_object.action()
  File "/usr/lib/python3/dist-packages/morse/core/sensor.py", line 76, in action
    self.default_action()
  File "/usr/lib/python3/dist-packages/morse/sensors/armature_pose.py", line 162, in default_action
    joints = self.get_state()
  File "/usr/lib/python3/dist-packages/morse/sensors/armature_pose.py", line 117, in get_state
    joints[channel.name] = self.get_joint(channel.name)
  File "/usr/lib/python3/dist-packages/morse/sensors/armature_pose.py", line 135, in get_joint
    return self._armature_actuator._get_joint_value(joint) # reuse helper functions from armature actuator
  File "/usr/lib/python3/dist-packages/morse/actuators/armature.py", line 226, in _get_joint_value
    axis_index = next(i for i, j in enumerate(self.find_dof(channel)) if j)
StopIteration

Builder script for the robot:

from morse.builder import *

class Pantilt(GroundRobot):
    """
    A template robot model for PanTilt, with a motion controller and a pose sensor.
    """
    def __init__(self, name = None, debug = True):

        # PanTilt.blend is located in the data/robots directory
        Robot.__init__(self, 'pantilt/robots/pantilt.blend', name)
        self.properties(classpath = "pantilt.robots.PanTilt.Pantilt")

        ###################################
        # Actuators
        ###################################


        self.armature = Armature(armature_name = "Armature")
        self.armature.create_ik_targets(["CameraBone"])
        self.arm_pose = ArmaturePose()
        self.armature.append(self.arm_pose)
        self.append(self.armature)

Removing the fixed last bone in the armature fixes the issue.

[skadge]

Also, using this same robot, I've not been able to control the armature from pymorse, neither in joint space or via IK targets.

For instance:

simu.robot.armature.set_rotation("Tilt", 1)

does nothing, neither:

simu.robot.armature.place_IK_target("ik_target.robot.armature.Roll", [1,1,1],[0,0,0])

MORSE does not give any error messages (all calls are SUCCESS)

[adegroote]

all armature bugs belong to you :)

[severin-lemaignan]

The bug is very likely here: https://github.com/morse-simulator/morse/blob/master/src/morse/actuators/armature.py#L634
When no IK limit is explicitely set, the values default to 0.0 according to Blender Python API doc.

[adegroote]

Do you speak about the first or the second issue ?

The first issue is basically that

next(i for i, j in enumerate(s) if j)

is quite smart, but does not work for s = [False, False, False].

It seems that the 'armature' interface does not provide support for fixed joint. If we do not want to support it, we can probably check it at the builder level, or emit something clearer for the user. If we want to support it, well, more work for you :D