ros_sugar.robot.mount#

Where a sensor sits on the robot.

A Mount is a recipe-level statement: this sensor is mounted there on this robot.

Mounts only describe static transforms. A sensor with moving parts (a pan-tilt head) publishes the dynamic transform from its own base frame to the moving one itself; the recipe then only has to say where that base frame sits, and the two compose in the TF tree.

Module Contents#

Classes#

Mount

A static placement of a sensor relative to something else.

Functions#

quaternion_from_euler

Convert roll/pitch/yaw (radians) to a quaternion (x, y, z, w).

pose_relative_to

Where one mounted thing sits in another’s frame.

API#

ros_sugar.robot.mount.quaternion_from_euler(roll: float, pitch: float, yaw: float) → Tuple[float, float, float, float]#

Convert roll/pitch/yaw (radians) to a quaternion (x, y, z, w).

ROS transforms carry quaternions while people describe mounts in roll, pitch and yaw, so a recipe states the readable form and this converts. Rotations compose in the ROS convention: yaw about Z, then pitch about Y, then roll about X.

Parameters:

  • roll – Rotation about X, in radians

  • pitch – Rotation about Y, in radians

  • yaw – Rotation about Z, in radians

Returns:

Quaternion as (x, y, z, w)

Return type:

Tuple[float, float, float, float]

ros_sugar.robot.mount.pose_relative_to(pose: Tuple[Tuple[float, float, float], Tuple[float, float, float]], frame: Tuple[Tuple[float, float, float], Tuple[float, float, float]]) → Tuple[Tuple[float, float, float], Tuple[float, float, float]]#

Where one mounted thing sits in another’s frame.

A robot knows where each of its sensors sits on its body, while whatever reads one of them usually wants another in its own frame. Both arguments and the result are (xyz, rpy) against the same parent.

Parameters:

  • pose – What is being placed, as (xyz, rpy) on the parent

  • frame – Whose frame to place it in, as (xyz, rpy) on the parent

Returns:

(xyz, rpy) of pose in frame

class ros_sugar.robot.mount.Mount#

Bases: ros_sugar.config.BaseAttrs

A static placement of a sensor relative to something else.

Name

Type, Default

Description

parent

str | Plugin

What the sensor is mounted on: the robot plugin, another sensor plugin, or a frame name such as the world frame for a fixed sensor.

xyz

tuple, (0, 0, 0)

Translation from the parent frame to the sensor frame, in metres.

rpy

tuple, (0, 0, 0)

Rotation from the parent frame to the sensor frame, in radians.
property parent_frame: str#

Frame this mount is relative to.

property child_frame: str#

Frame being placed.

asdict(filter: Optional[Callable] = None) → Dict#

Convert class to dict.

Return type:

dict

to_dict() → Dict#

Convert class to dict.

Return type:

dict

asdict_explicit() → Dict#

Convert to dict, keeping only what differs from the class defaults.

See explicit_fields, which this defers to.

Returns:

Fields that differ from the defaults

Return type:

dict

from_dict(dict_obj: Dict) → None#

Gets attributes values from given dictionary

Parameters:

dict_obj (Dict) – Dictionary {attribute_name: attribute_value}

Raises:

  • ValueError – If attribute_name in dictionary does not exists in class attributes

  • TypeError – If attribute_value type in dictionary does not correspond to class attribute type

from_file(file_path: str, nested_root_name: Union[str, None] = None, get_common: bool = False) → bool#

Update class attributes from yaml, json, or toml

Parameters:

  • file_path – Path to config file (.yaml, .json, .toml)

  • nested_root_name – Nested root name for the config, defaults to None

  • get_common – Whether to get extra config root (for merging), defaults to False

to_json() → Union[str, bytes, bytearray]#

Dump to json

Returns:

description

Return type:

str | bytes | bytearray

from_json(json_obj: Union[str, bytes, bytearray]) → None#

Gets attributes values from given json

Parameters:

json_obj (str | bytes | bytearray) – Json object

has_attribute(attr_name: str) → bool#

Checks if class object has attribute with given name

Parameters:

attr_name (str) – description

Returns:

If object has attribute with given name

Return type:

bool

get_attribute_type(attr_name: str) → Optional[type]#

Gets type of given attribute name

Parameters:

attr_name (str) – description

Raises:

AttributeError – If class does not have attribute with given name

Returns:

Attribute type

Return type:

type

update_value(attr_name: str, attr_value: Any) → bool#

Updates the value of an attribute in the class

Parameters:

  • attr_name (str) – Attribute name - can be nested name

  • attr_value (Any) – Attribute value

Raises:

  • AttributeError – If class does not contain attribute with given name

  • TypeError – If class attribute with given name if of different type

Returns:

If attribute value is updated

Return type:

bool

classmethod get_fields_info(class_object) → Dict[str, Dict[str, Any]]#

Returns a dictionary with metadata about each field in the class.

This includes the field’s name, type annotation, and parsed validator info.

Returns:

A dictionary where keys are field names and values are dicts of metadata.