Gripper

Instruct the robot to move towards a given target

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.

Configuration parameters for Gripper

You can set these properties in your scripts with <component>.properties(<property1>=..., <property2>=...).

  • Angle (float, default: 60.0)

    Aperture angle of the radar capable to detecting the graspable objects (in degree)

  • Distance (float, default: 0.5)

    Detection distance in meter. Graspable objects further way from the gripper than this distance cannot be held

Data fields

This actuator reads these datafields at each simulation step:

  • grab (bool, initial value: False)

    Currently not used

Interface support:

Services for Gripper

  • get_properties() (blocking)

    Returns the properties of a component.

    • Return value

      a dictionary of the current component’s properties

  • set_property(prop_name, prop_val) (blocking)

    Modify one property on a component

    • Parameters

      • prop_name: the name of the property to modify (as shown the documentation)
      • prop_val: the new value of the property. Note that there is no checking about the type of the value so be careful
    • Return value

      nothing

  • grab() (blocking)

    Tries to grab an object close to the gripper.

    • Return value

      if successful (or if an object is already in hand), the name of the object, else None.

  • release() (blocking)

    Free the grabbed object.

    Let it fall down after resetting its rotation. Does nothing if no object is held.

    • Return value

      True if an object has been released, else False (if no object was held).

  • get_configurations() (blocking)

    Returns the configurations of a component (parsed from the properties).

    • Return value

      a dictionary of the current component’s configurations

Examples

The following examples show how to use this component in a Builder script:

from morse.builder import *

# adds a default robot (the MORSE mascott!)
robot = Morsy()

# creates a new instance of the actuator
gripper = Gripper()

# place your component at the correct location
gripper.translate(<x>, <y>, <z>)
gripper.rotate(<rx>, <ry>, <rz>)

robot.append(gripper)

# define one or several communication interface, like 'socket'
gripper.add_interface(<interface>)

env = Environment('empty')

Other sources of examples

(This page has been auto-generated from MORSE module morse.actuators.gripper.)

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