Source code for morse.actuators.gripper
import logging; logger = logging.getLogger("morse." + __name__)
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#
# gripper.py Blender 2.59
#
# Gilberto Echeverria
# 13 / 10 / 2010
#
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import morse.core.actuator
from morse.core import blenderapi
from morse.core.services import service
from morse.helpers.components import add_data, add_property
[docs]class Gripper(morse.core.actuator.Actuator):
"""
Actuator capable of grabbing objects marked with the ``Graspable``
Game Property. Currently it only works using services: **grab** and
**release**. When instructed to grab an object, it will check if it
is within range, and if so, will parent the grabbed object to
itself.
.. note::
For objects to be detected and grabbed by the gripper, they must
have the following settings in the **Physics Properties** panel:
- **Actor** must be checked
- **Collision Bounds** must be checked
- **Physics Type** must be ``Rigid Body``
This will work even for Static objects
.. warning::
This actuator does not simulate the physical interaction of the
gripper fingers with the objects it grabs. Its purpose is to
abstract the action of taking an object, for human-robot
interaction experiments.
"""
_name = "Gripper"
_short_desc = "Instruct the robot to move towards a given target"
add_data('grab', False, "bool", "Currently not used")
# These properties are not used directly in the logic, but are used
# in the builder to create the radar properly.
# These value cannot be changed dynamically in bge.
add_property('_angle', 60.0, 'Angle', 'float',
'Aperture angle of the radar capable to detecting the \
graspable objects (in degree)')
add_property('_distance', 0.5, 'Distance', 'float',
'Detection distance in meter. Graspable objects further \
way from the gripper than this distance cannot be \
held')
def __init__(self, obj, parent=None):
"""
Constructor method.
Receives the reference to the Blender object.
"""
logger.info('%s initialization' % obj.name)
# Call the constructor of the parent class
morse.core.actuator.Actuator.__init__(self, obj, parent)
self._near_object = None
self._grabbed_object = None
# Variable to indicate whether the mesh should animate closing
# or opening the gripper
self._animation = ''
# Get references to the Logic Bricks to play animations
self._contr = self.bge_object.controllers[0]
self._close_anim = self._contr.actuators['Close_anim']
self._open_anim = self._contr.actuators['Open_anim']
logger.info('Component initialized')
logger.setLevel(logging.DEBUG)
[docs] def find_object(self):
"""
Store the object that is within reach of the gripper Uses a
Blender Radar Sensor to detect objects with the 'Graspable'
property in front of this component
"""
# Get reference to the Radar Blender sensor
contr = blenderapi.controller()
radar = contr.sensors['Radar']
self._near_object = None
if radar.triggered and radar.positive:
min_distance = 100
for test_obj in radar.hitObjectList:
# Find the closest object and its distance
new_distance = self.bge_object.getDistanceTo(test_obj)
if new_distance < min_distance:
self._near_object = test_obj
min_distance = new_distance
[docs] @service
def grab(self):
"""
Tries to grab an object close to the gripper.
:returns: if successful (or if an object is already in hand), the
name of the object, else None.
"""
# Check that no other object is being carried
if not self._grabbed_object:
# If the object is draggable
if self._near_object is not None:
logger.debug("Grabbing object: '%s'" % self._near_object)
# Remove Physic simulation
#self._near_object.suspendDynamics()
# Parent the selected object to the gripper
self._grabbed_object = self._near_object
self._grabbed_object.setParent (self.bge_object)
logger.debug("New parent: %s" % self._grabbed_object.parent)
self._near_object = None
# Execute the close grip animation:
self._animation = 'close'
return self._grabbed_object.name
else:
logger.debug("No 'Graspable' object within range of gripper")
return None
else:
logger.debug("Already holding object %s" % self._grabbed_object )
return self._grabbed_object.name
[docs] @service
def release(self):
"""
Free the grabbed object.
Let it fall down after resetting its rotation.
Does nothing if no object is held.
:returns: True if an object has been released, else False (if
no object was held).
"""
# Clear the previously selected object, if any
if self._grabbed_object is not None:
logger.debug("Releasing object: '%s'" % self._near_object)
# Remove the parent
self._grabbed_object.removeParent()
# Place the object on the nearest surface
#morse.helpers.place_object.do_place(previous_object)
# Reset rotation of object
#self._grabbed_object.worldOrientation = [0.0, 0.0, 0.0]
# Restore Physics simulation
#previous_object.restoreDynamics()
#previous_object.setLinearVelocity([0, 0, 0])
#previous_object.setAngularVelocity([0, 0, 0])
# Clear the object from dragged status
self._grabbed_object = None
# Execute the open grip animation:
self._animation = 'open'
return True
else:
logger.debug("No object currently being held: nothing to release.")
return False
[docs] def default_action(self):
"""
Check if an object is within reach of the hand
"""
self.find_object()
# Play the animations when necessary
if self._animation == 'close':
self._contr.activate(self._close_anim)
self._animation = ''
logger.debug('Playing CLOSE animation')
if self._animation == 'open':
self._contr.activate(self._open_anim)
self._animation = ''
logger.debug('Playing OPEN animation')
