simulation.utils.urdf package¶

Module package to create .urdf model definitions.

The package contains a number of classes that enable to define urdf robots through python.

For what? The urdf is very repetetive to write and requires prior knowledge on available tags and how they can be combined to a fully specified robot. Additionally, the commonly used xacro is less powerful than python and, again, another tool.

The basic idea used throughout the package is the inheritance from XmlObject. XmlObject.create_xml() creates a xml.etree.cElementTree.Element from the class instance. It does so by converting all instance attributes into xml attributes and sub elements. If a class attribute is an instance of a subclass of XmlObject, the objects XmlObject.create_xml() is called recursively.

The XmlObject in combination with dataclasses allows to create lightweight classes that define urdf components when converted to xml.

Submodules:

Summary¶

__all__ Classes:

`Attribute`	Basic class that will be converted into a xml attribute.
`Axis`	Axis(xyz: simulation.utils.urdf.core.Attribute = <factory>)
`Box`	Box(size: simulation.utils.urdf.core.Attribute)
`CameraClip`	CameraClip(near: float, far: float)
`CameraDefinition`	CameraDefinition(horizontal_fov: float, image: simulation.utils.urdf.camera.CameraImage, clip: simulation.utils.urdf.camera.CameraClip = None)
`CameraImage`	CameraImage(width: int, height: int, format: str)
`CameraPlugin`	CameraPlugin(name: simulation.utils.urdf.core.Attribute, filename: simulation.utils.urdf.core.Attribute, alwaysOn: float = 1, updateRate: float = 0, frameName: str = None, cameraName: str = None, CxPrime: float = None, Cx: float = None, Cy: float = None)
`CameraProperties`	CameraProperties(horizontal_fov: float, update_rate: float, image_width: float, image_height: float, image_format: float, clip_near: float, clip_far: float, image_topic: str, info_topic: str, frame_name: str, optical_center_x: float = None, optical_center_y: float = None)
`CameraSensor`	CameraSensor(name: simulation.utils.urdf.core.Attribute, type: simulation.utils.urdf.core.Attribute, plugin: simulation.utils.urdf.camera.CameraPlugin, update_rate: float, camera: simulation.utils.urdf.camera.CameraDefinition)
`Child`	Child(link: simulation.utils.urdf.core.Attribute)
`Collision`	Collision(origin: simulation.utils.urdf.core.Origin = None, geometry: simulation.utils.urdf.link.Geometry = None)
`Color`	Color(xyz: simulation.utils.urdf.core.Attribute = <factory>)
`Cylinder`	Cylinder(radius: simulation.utils.urdf.core.Attribute, length: simulation.utils.urdf.core.Attribute)
`DepthCamera`	DepthCamera(name: str, origin: simulation.utils.urdf.core.Origin, size: simulation.utils.geometry.vector.Vector, mass: float, properties: simulation.utils.urdf.camera.DepthCameraProperties, chassis_link: simulation.utils.urdf.link.Link)
`DepthCameraPlugin`	DepthCameraPlugin(name: simulation.utils.urdf.core.Attribute = ‘camera_plugin’, filename: simulation.utils.urdf.core.Attribute = ‘libgazebo_ros_openni_kinect.so’, alwaysOn: float = 1, updateRate: float = 0, frameName: str = None, cameraName: str = None, CxPrime: float = None, Cx: float = None, Cy: float = None, depthImageTopicName: str = None, depthImageCameraInfoTopicName: str = None, pointCloudTopicName: str = None, pointCloudCutoff: float = None)
`DepthCameraProperties`	DepthCameraProperties(horizontal_fov: float, update_rate: float, image_width: float, image_height: float, image_format: float, clip_near: float, clip_far: float, image_topic: str, info_topic: str, frame_name: str, optical_center_x: float = None, optical_center_y: float = None, point_cloud_cutoff: float = None, point_cloud_topic_name: str = None)
`Gazebo`	Gazebo(inner: simulation.utils.urdf.core.XmlObject, reference: simulation.utils.urdf.core.Attribute = None)
`Geometry`	Geometry(value: simulation.utils.urdf.core.XmlObject)
`Inertia`	Inertia(ixx: simulation.utils.urdf.core.Attribute = 0, ixy: simulation.utils.urdf.core.Attribute = 0, ixz: simulation.utils.urdf.core.Attribute = 0, iyx: simulation.utils.urdf.core.Attribute = 0, iyy: simulation.utils.urdf.core.Attribute = 0, iyz: simulation.utils.urdf.core.Attribute = 0, izx: simulation.utils.urdf.core.Attribute = 0, izy: simulation.utils.urdf.core.Attribute = 0, izz: simulation.utils.urdf.core.Attribute = 0)
`Inertial`	Inertial(mass: float, inertia: simulation.utils.urdf.link.Inertia, origin: simulation.utils.urdf.core.Origin = None)
`Joint`	Joint(name: simulation.utils.urdf.core.Attribute, parent: simulation.utils.urdf.joint.Parent, child: simulation.utils.urdf.joint.Child, type: simulation.utils.urdf.core.Attribute = ‘fixed’, axis: simulation.utils.geometry.vector.Vector = None, limit: simulation.utils.urdf.joint.JointLimit = None, dynamics: simulation.utils.urdf.joint.JointDynamics = None, origin: simulation.utils.urdf.core.Origin = None)
`JointDynamics`	JointDynamics(damping: simulation.utils.urdf.core.Attribute = None, friction: simulation.utils.urdf.core.Attribute = None)
`JointLimit`	JointLimit(effort: simulation.utils.urdf.core.Attribute = None, lower: simulation.utils.urdf.core.Attribute = None, upper: simulation.utils.urdf.core.Attribute = None, velocity: simulation.utils.urdf.core.Attribute = None)
`Link`	Link(name: simulation.utils.urdf.core.Attribute, collision: simulation.utils.urdf.link.Collision = None, visual: simulation.utils.urdf.link.Collision = None, inertial: simulation.utils.urdf.link.Inertial = None)
`Material`	Material(name: simulation.utils.urdf.core.Attribute = None, color: simulation.utils.geometry.vector.Vector = None, texture: str = None)
`Mesh`	Mesh(filename: simulation.utils.urdf.core.Attribute, scale: simulation.utils.geometry.vector.Vector = None)
`MonoCamera`	MonoCamera(name: str, origin: simulation.utils.urdf.core.Origin, size: simulation.utils.geometry.vector.Vector, mass: float, properties: simulation.utils.urdf.camera.CameraProperties, chassis_link: simulation.utils.urdf.link.Link)
`Origin`	Origin(xyz: simulation.utils.urdf.core.Attribute = <factory>, rpy: simulation.utils.urdf.core.Attribute = <factory>)
`Parent`	Parent(link: simulation.utils.urdf.core.Attribute)
`Plugin`	Plugin(name: simulation.utils.urdf.core.Attribute, filename: simulation.utils.urdf.core.Attribute)
`Sensor`	Sensor(name: simulation.utils.urdf.core.Attribute, type: simulation.utils.urdf.core.Attribute)
`Sphere`	Sphere(radius: simulation.utils.urdf.core.Attribute)
`Visual`	Visual(origin: Tuple = None, geometry: simulation.utils.urdf.link.Geometry = None, material: simulation.utils.urdf.link.Material = None)
`XmlObject`	Base class for all urdf xml objects.

class Attribute(val: str, name: Optional[str] = None)[source]¶

Basic class that will be converted into a xml attribute.

Important: Within a subclass of XmlObject an attribute can be defined by simply annotating a class variable with py:class:Attribute!

Example

>>> from dataclasses import dataclass
>>> from urdf.core import XmlObject, Attribute
>>> @dataclass
... class Example(XmlObject):
...     TAG = "example"
...     name: Attribute
...     value1: str
...     value2: float = None
>>> ex = Example("example_name",value1="I'm an example.")

The code block defines a simple example class that results in the xml string:

<example name="example_name">
  <value1>I'm an example.</value1>
</example>

Parameters

val – Attribute value.
name – Optionally the name of the can be provided. By default the name of the Attribute instance defines the name of the resulting xml attribute.

class XmlObject[source]¶

Base class for all urdf xml objects.

TAG = None¶

_get_val(val: Any) → str[source]¶: Convert a value to a string that is included into the xml.

create_xml(root_el: Optional[xml.etree.ElementTree.Element] = None) → xml.etree.ElementTree.Element[source]¶

Convert this instance into a xml element.

If the class of this instance does not define a tag, new xml elements from this instance are appended to the root_el. Otherwise, a sub element is created and returned.
Additionally to all instance attributes, a dictionary parameters can be used to define sub elements.
A Attribute type annotation for any of the object`s attributes, will result in a xml attribute.

Parameters: root_el – Optional element that is used a parent xml element when provided.

save(file_path: str)[source]¶

Save this instance as a xml string to a file.

Parameters: file_path – Location to store the xml.

class Origin(xyz: simulation.utils.urdf.core.Attribute = <factory>, rpy: simulation.utils.urdf.core.Attribute = <factory>)[source]¶

TAG = 'origin'¶

xyz: simulation.utils.urdf.core.Attribute¶

rpy: simulation.utils.urdf.core.Attribute¶

classmethod from_vector(vector: simulation.utils.geometry.vector.Vector)[source]¶

classmethod from_list(lst: List[float])[source]¶

class Axis(xyz: simulation.utils.urdf.core.Attribute = <factory>)[source]¶

TAG = 'axis'¶

xyz: simulation.utils.urdf.core.Attribute¶

class Color(xyz: simulation.utils.urdf.core.Attribute = <factory>)[source]¶

TAG = 'color'¶

xyz: simulation.utils.urdf.core.Attribute¶

class Inertia(ixx: simulation.utils.urdf.core.Attribute = 0, ixy: simulation.utils.urdf.core.Attribute = 0, ixz: simulation.utils.urdf.core.Attribute = 0, iyx: simulation.utils.urdf.core.Attribute = 0, iyy: simulation.utils.urdf.core.Attribute = 0, iyz: simulation.utils.urdf.core.Attribute = 0, izx: simulation.utils.urdf.core.Attribute = 0, izy: simulation.utils.urdf.core.Attribute = 0, izz: simulation.utils.urdf.core.Attribute = 0)[source]¶

TAG = 'inertia'¶

ixx: simulation.utils.urdf.core.Attribute = 0¶

ixy: simulation.utils.urdf.core.Attribute = 0¶

ixz: simulation.utils.urdf.core.Attribute = 0¶

iyx: simulation.utils.urdf.core.Attribute = 0¶

iyy: simulation.utils.urdf.core.Attribute = 0¶

iyz: simulation.utils.urdf.core.Attribute = 0¶

izx: simulation.utils.urdf.core.Attribute = 0¶

izy: simulation.utils.urdf.core.Attribute = 0¶

izz: simulation.utils.urdf.core.Attribute = 0¶

class Inertial(mass: float, inertia: simulation.utils.urdf.link.Inertia, origin: simulation.utils.urdf.core.Origin = None)[source]¶

TAG = 'inertial'¶

mass: float¶

inertia: simulation.utils.urdf.link.Inertia¶

origin: simulation.utils.urdf.core.Origin = None¶

create_xml(root_el=None)[source]¶

Convert this instance into a xml element.

If the class of this instance does not define a tag, new xml elements from this instance are appended to the root_el. Otherwise, a sub element is created and returned.
Additionally to all instance attributes, a dictionary parameters can be used to define sub elements.
A Attribute type annotation for any of the object`s attributes, will result in a xml attribute.

Parameters: root_el – Optional element that is used a parent xml element when provided.

class Box(size: simulation.utils.urdf.core.Attribute)[source]¶

TAG = 'box'¶

size: simulation.utils.urdf.core.Attribute¶

calculate_inertia(mass) → simulation.utils.urdf.link.Inertia [source]¶

class Sphere(radius: simulation.utils.urdf.core.Attribute)[source]¶

TAG = 'sphere'¶

radius: simulation.utils.urdf.core.Attribute¶

calculate_inertia(mass) → simulation.utils.urdf.link.Inertia [source]¶

class Cylinder(radius: simulation.utils.urdf.core.Attribute, length: simulation.utils.urdf.core.Attribute)[source]¶

TAG = 'cylinder'¶

radius: simulation.utils.urdf.core.Attribute¶

length: simulation.utils.urdf.core.Attribute¶

calculate_inertia(mass) → simulation.utils.urdf.link.Inertia [source]¶

class Geometry(value: simulation.utils.urdf.core.XmlObject)[source]¶

TAG = 'geometry'¶

value: simulation.utils.urdf.core.XmlObject¶

class Mesh(filename: simulation.utils.urdf.core.Attribute, scale: simulation.utils.geometry.vector.Vector = None)[source]¶

TAG = 'mesh'¶

filename: simulation.utils.urdf.core.Attribute¶

scale: simulation.utils.geometry.vector.Vector = None¶

class Material(name: simulation.utils.urdf.core.Attribute = None, color: simulation.utils.geometry.vector.Vector = None, texture: str = None)[source]¶

TAG = 'material'¶

name: simulation.utils.urdf.core.Attribute = None¶

color: simulation.utils.geometry.vector.Vector = None¶

texture: str = None¶

class Visual(origin: Tuple = None, geometry: simulation.utils.urdf.link.Geometry = None, material: simulation.utils.urdf.link.Material = None)[source]¶

TAG = 'visual'¶

origin: Tuple = None¶

geometry: simulation.utils.urdf.link.Geometry = None¶

material: simulation.utils.urdf.link.Material = None¶

class Collision(origin: simulation.utils.urdf.core.Origin = None, geometry: simulation.utils.urdf.link.Geometry = None)[source]¶

TAG = 'collision'¶

origin: simulation.utils.urdf.core.Origin = None¶

geometry: simulation.utils.urdf.link.Geometry = None¶

class Link(name: simulation.utils.urdf.core.Attribute, collision: simulation.utils.urdf.link.Collision = None, visual: simulation.utils.urdf.link.Collision = None, inertial: simulation.utils.urdf.link.Inertial = None)[source]¶

TAG = 'link'¶

name: simulation.utils.urdf.core.Attribute¶

collision: simulation.utils.urdf.link.Collision = None¶

visual: simulation.utils.urdf.link.Collision = None¶

inertial: simulation.utils.urdf.link.Inertial = None¶

use_inertial_from_collision(mass: float)[source]¶

class JointDynamics(damping: simulation.utils.urdf.core.Attribute = None, friction: simulation.utils.urdf.core.Attribute = None)[source]¶

TAG = 'dynamics'¶

damping: simulation.utils.urdf.core.Attribute = None¶

friction: simulation.utils.urdf.core.Attribute = None¶

class JointLimit(effort: simulation.utils.urdf.core.Attribute = None, lower: simulation.utils.urdf.core.Attribute = None, upper: simulation.utils.urdf.core.Attribute = None, velocity: simulation.utils.urdf.core.Attribute = None)[source]¶

TAG = 'limit'¶

effort: simulation.utils.urdf.core.Attribute = None¶

lower: simulation.utils.urdf.core.Attribute = None¶

upper: simulation.utils.urdf.core.Attribute = None¶

velocity: simulation.utils.urdf.core.Attribute = None¶

class Parent(link: simulation.utils.urdf.core.Attribute)[source]¶

TAG = 'parent'¶

link: simulation.utils.urdf.core.Attribute¶

class Child(link: simulation.utils.urdf.core.Attribute)[source]¶

TAG = 'child'¶

link: simulation.utils.urdf.core.Attribute¶

class Joint(name: simulation.utils.urdf.core.Attribute, parent: simulation.utils.urdf.joint.Parent, child: simulation.utils.urdf.joint.Child, type: simulation.utils.urdf.core.Attribute = 'fixed', axis: simulation.utils.geometry.vector.Vector = None, limit: simulation.utils.urdf.joint.JointLimit = None, dynamics: simulation.utils.urdf.joint.JointDynamics = None, origin: simulation.utils.urdf.core.Origin = None)[source]¶

TAG = 'joint'¶

FIXED = 'fixed'¶

REVOLUTE = 'revolute'¶

CONTINUOUS = 'continuous'¶

name: simulation.utils.urdf.core.Attribute¶

parent: simulation.utils.urdf.joint.Parent¶

child: simulation.utils.urdf.joint.Child¶

type: simulation.utils.urdf.core.Attribute = 'fixed'¶

axis: simulation.utils.geometry.vector.Vector = None¶

limit: simulation.utils.urdf.joint.JointLimit = None¶

dynamics: simulation.utils.urdf.joint.JointDynamics = None¶

origin: simulation.utils.urdf.core.Origin = None¶

class Plugin(name: simulation.utils.urdf.core.Attribute, filename: simulation.utils.urdf.core.Attribute)[source]¶

TAG = 'plugin'¶

name: simulation.utils.urdf.core.Attribute¶

filename: simulation.utils.urdf.core.Attribute¶

class Gazebo(inner: simulation.utils.urdf.core.XmlObject, reference: simulation.utils.urdf.core.Attribute = None)[source]¶

TAG = 'gazebo'¶

inner: simulation.utils.urdf.core.XmlObject¶

reference: simulation.utils.urdf.core.Attribute = None¶

class Sensor(name: simulation.utils.urdf.core.Attribute, type: simulation.utils.urdf.core.Attribute)[source]¶

TAG = 'sensor'¶

name: simulation.utils.urdf.core.Attribute¶

type: simulation.utils.urdf.core.Attribute¶

class MonoCamera(name: str, origin: simulation.utils.urdf.core.Origin, size: simulation.utils.geometry.vector.Vector, mass: float, properties: simulation.utils.urdf.camera.CameraProperties, chassis_link: simulation.utils.urdf.link.Link)[source]¶

sensor: simulation.utils.urdf.camera.CameraSensor¶

link: simulation.utils.urdf.link.Link¶

joint: simulation.utils.urdf.joint.Joint¶

plugin: simulation.utils.urdf.gazebo.Gazebo¶

class DepthCamera(name: str, origin: simulation.utils.urdf.core.Origin, size: simulation.utils.geometry.vector.Vector, mass: float, properties: simulation.utils.urdf.camera.DepthCameraProperties, chassis_link: simulation.utils.urdf.link.Link)[source]¶

link: simulation.utils.urdf.link.Link¶

joint: simulation.utils.urdf.joint.Joint¶

plugin: simulation.utils.urdf.gazebo.Gazebo¶

sensor: simulation.utils.urdf.camera.CameraSensor¶

class CameraClip(near: float, far: float)[source]¶

TAG = 'clip'¶

near: float¶

far: float¶

class CameraDefinition(horizontal_fov: float, image: simulation.utils.urdf.camera.CameraImage, clip: simulation.utils.urdf.camera.CameraClip = None)[source]¶

TAG = 'camera'¶

horizontal_fov: float¶

image: simulation.utils.urdf.camera.CameraImage¶

clip: simulation.utils.urdf.camera.CameraClip = None¶

class CameraImage(width: int, height: int, format: str)[source]¶

TAG = 'image'¶

width: int¶

height: int¶

format: str¶

class CameraPlugin(name: simulation.utils.urdf.core.Attribute, filename: simulation.utils.urdf.core.Attribute, alwaysOn: float = 1, updateRate: float = 0, frameName: str = None, cameraName: str = None, CxPrime: float = None, Cx: float = None, Cy: float = None)[source]¶

alwaysOn: float = 1¶

updateRate: float = 0¶

frameName: str = None¶

cameraName: str = None¶

CxPrime: float = None¶

Cx: float = None¶

Cy: float = None¶

class DepthCameraPlugin(name: simulation.utils.urdf.core.Attribute = 'camera_plugin', filename: simulation.utils.urdf.core.Attribute = 'libgazebo_ros_openni_kinect.so', alwaysOn: float = 1, updateRate: float = 0, frameName: str = None, cameraName: str = None, CxPrime: float = None, Cx: float = None, Cy: float = None, depthImageTopicName: str = None, depthImageCameraInfoTopicName: str = None, pointCloudTopicName: str = None, pointCloudCutoff: float = None)[source]¶

name: simulation.utils.urdf.core.Attribute = 'camera_plugin'¶

filename: simulation.utils.urdf.core.Attribute = 'libgazebo_ros_openni_kinect.so'¶

depthImageTopicName: str = None¶

depthImageCameraInfoTopicName: str = None¶

pointCloudTopicName: str = None¶

pointCloudCutoff: float = None¶

class CameraSensor(name: simulation.utils.urdf.core.Attribute, type: simulation.utils.urdf.core.Attribute, plugin: simulation.utils.urdf.camera.CameraPlugin, update_rate: float, camera: simulation.utils.urdf.camera.CameraDefinition)[source]¶

name: simulation.utils.urdf.core.Attribute¶

type: simulation.utils.urdf.core.Attribute¶

plugin: simulation.utils.urdf.camera.CameraPlugin¶

update_rate: float¶

camera: simulation.utils.urdf.camera.CameraDefinition¶

class CameraProperties(horizontal_fov: float, update_rate: float, image_width: float, image_height: float, image_format: float, clip_near: float, clip_far: float, image_topic: str, info_topic: str, frame_name: str, optical_center_x: float = None, optical_center_y: float = None)[source]¶

horizontal_fov: float¶

update_rate: float¶

image_width: float¶

image_height: float¶

image_format: float¶

clip_near: float¶

clip_far: float¶

image_topic: str¶

info_topic: str¶

frame_name: str¶

optical_center_x: float = None¶

optical_center_y: float = None¶

class DepthCameraProperties(horizontal_fov: float, update_rate: float, image_width: float, image_height: float, image_format: float, clip_near: float, clip_far: float, image_topic: str, info_topic: str, frame_name: str, optical_center_x: float = None, optical_center_y: float = None, point_cloud_cutoff: float = None, point_cloud_topic_name: str = None)[source]¶

point_cloud_cutoff: float = None¶

point_cloud_topic_name: str = None¶