Table of Contents

The Giskard wrapper has several functions to add objects to the scene or to attach them to one of the links of the robot. Below is a list of all these functions with examples how to use them. At the bottom of the page you can find a Python example that demonstrates how to attach a box to one of the tip links of the PR2. In order to display the added objects in rviz you have to add a MarkerArray that listens to the topic /giskard/visualization_marker_array. There Giskard publishes markers of the added objects.

add_box

Description:
add_box() adds a box at the specified position in the given frame.

Parameters:
name: the name of the box
size: the length of the X,Y and Z side of the box.
frame_id: the frame in which the box is added
position: the coordinates where the box is added relative to the frame in frame_id
orientation: a quaternion that describes the orientation of the box relative to the frame in frame_id

Example:

add_box(self, name='box', size=(1, 1, 1), frame_id=u'map', position=(0, 0, 0), orientation=(0, 0, 0, 1))

add_sphere

Description:
add_sphere() adds a sphere at the specified position in the given frame.

Parameters:
name: the name of the sphere
size: the radius of the sphere
frame_id: the frame in which the sphere is added
position: the coordinates where the sphere is added relative to the frame in frame_id
orientation: a quaternion that describes the orientation of the sphere relative to the frame in frame_id

Example:

add_sphere(self, name='sphere', size=1, frame_id='map', position=(0,0,0), orientation=(0,0,0,1))

add_cylinder

Description:
add_cylinder() adds a cylinder at the specified position in the given frame.

Parameters:
name: the name of the cylinder
size: the height and radius of the cylinder
frame_id: the frame in which the cylinder is added
position: the coordinates where the cylinder is added relative to the frame in frame_id
orientation: a quaternion that describes the orientation of the cylinder relative to the frame in frame_id

Example:

add_cylinder(self, name='cylinder', size=(1,1), frame_id='map', position=(0,0,0), orientation=(0,0,0,1))

add_urdf

Description:
add_urdf() adds a robot described by a urdf at the specified position in the given frame.

Parameters:
name: the name of the cylinder
urdf: the urdf of the robot
js_topic: the joint state topic the robot listens on
pose: a geometry_msgs/PoseStamped that describes the position of robot

Example:

p = PoseStamped()
add_urdf(self, name='urdf_robot', urdf='urdf_string', js_topic='/js_topic', pose=p)

attach_box

Description:
attach_box() attaches a box to the specified frame.

Parameters:
name: the name of the box
size: the length of the X,Y and Z side of the box.
frame_id: the frame the box will be attached to
position: the coordinates where the box is added relative to the frame in frame_id
orientation: a quaternion that describes the orientation of the box relative to the frame in frame_id

Example:

attach_box(self, name='box', size=(1, 1, 1), frame_id=u'map', position=(0, 0, 0), orientation=(0, 0, 0, 1))

remove_object

Description:
remove_object() removes the object with the given name.

Parameters:
name: the name of the object

Example:

remove_object(self, name='object_name')

Python Example

The following code demonstrates how to attach a box to the left gripper of the PR2. It also shows that the collision avoidance works with attached objects. 

import rospy
from giskardpy.python_interface import GiskardWrapper
from geometry_msgs.msg import PoseStamped
 
# the starting pose for this tutorial
starting_pose = {
    'l_elbow_flex_joint': - 1.1343683863086362,
    'l_forearm_roll_joint': 7.517553513504836,
    'l_shoulder_lift_joint': 0.5726770101613905,
    'l_shoulder_pan_joint': 0.1592669164939349,
    'l_upper_arm_roll_joint': 0.5532568387077381,
    'l_wrist_flex_joint': - 1.215660155912625,
    'l_wrist_roll_joint': 4.249300323527076,
    'r_forearm_roll_joint': 0.0,
    'r_shoulder_lift_joint': 0.0,
    'r_shoulder_pan_joint': 0.0,
    'r_upper_arm_roll_joint': 0.0,
    'r_wrist_roll_joint': 0.0,
    'r_elbow_flex_joint': 0.0,
    'r_wrist_flex_joint': 0.0,
    'torso_lift_joint': 0.2}
 
l_tip = "l_gripper_tool_frame"
r_tip = 'r_gripper_tool_frame'
default_root = 'base_link'
 
rospy.init_node('test')
 
giskard_wrapper = GiskardWrapper()
 
# move the robot into starting position by setting a joint goal and executing it
giskard_wrapper.set_joint_goal(starting_pose)
giskard_wrapper.plan_and_execute()
 
# attach a box to the left gripper
attached_link_name = 'box'
giskard_wrapper.attach_box(attached_link_name, [0.1, 0.02, 0.02], l_tip, [0.05, 0, 0])
 
# set a joint goal to prevent the PR2 from lifting the torso
giskard_wrapper.set_joint_goal({'torso_lift_joint': 0.2})
 
# create a cartesian goal for the left gripper 20cm above the current position
p = PoseStamped()
p.header.frame_id = l_tip
p.pose.position.z = 0.2
p.pose.orientation.w = 1
 
# set the cartesian goal and execute it
giskard_wrapper.set_cart_goal(default_root, l_tip, p)
giskard_wrapper.plan_and_execute()
 
# remove the attached box
giskard_wrapper.remove_object(attached_link_name)