motion_stack.api.launch package

ROS2 launch api

Submodules

motion_stack.api.launch.builder module

API to generate launch files

class motion_stack.api.launch.builder.LevelBuilder(leg_dict, urdf_path=None, params_overwrite={}, urdf=None)

Bases: object

Builds a launcher for the motion stack generating your nodes

Note

This class is meant to be overloaded and changed for your robot. Refere to Launch API

Parameters:

• urdf_path (str | None) – Path of the urdf/xacro. A ROS2 Command will compile it and pass it as a string. See api.launch.builder.xacro_path_from_pkg() to get a path.

• leg_dict (Mapping[int, str | int]) – Dictionary linking leg number to end effector name. This informs the API of the number of legs and nodes to launch.

• params_overwrite (Dict[str, Any]) – Will overwrite the default parameters

• urdf (None | str | Command) – Full urdf (or command to compile it). Use this instead of urdf_path to compile with options or more. see api.launch.builder.xacro_path_from_pkg() and api.launch.builder.command_from_xacro_path()

Example:

from motion_stack.api.launch.builder import LevelBuilder, xacro_path_from_pkg

urdf_path = xacro_path_from_pkg(
    package_name="moonbot_zero_tuto", xacro_path="urdf/moonbot_zero.xacro"
)
LEGS_DIC = {
    1: "end1",
    2: "end2",
    3: "end3",
    4: "end4",
}
new_params = {
    "std_movement_time": 10.0,
}

lvl_builder = MyLevelBuilder(
    urdf_path=urdf_path,
    leg_dict=LEGS_DIC,
    params_overwrite=new_params,
)

def generate_launch_description():
    return lvl_builder.make_description()

OLD_PKG = 'easy_robot_control'

Type:    str

MS_PACKAGE = 'motion_stack'

Type:    str

make_description(levels=None)

Return the launch description for ros2

Example:

def generate_launch_description():
    return lvl_builder.make_description()

Parameters:

levels (List[List[Node]] | None) – list of levels, levels being a list of nodes to be launched

Returns:

launch description to launch all the nodes

Return type:

LaunchDescription

process_CLI_args()

lvl_to_launch()

Returns:

List of int corresponding to the motion stack levels to start

Return type:

List[int]

generate_global_params()

Generates parameters shared by all nodes. Based on the default params and overwrites.

make_leg_param(leg_index, ee_name)

Based on the leg index/number (and end-effector), returns the parameters corresponding to the leg

Parameters:

• leg_index (int) – leg number to create the params for

• ee_name (None | str | int) – (Optional) end effector name or number

Raises:

Exception – Exception(f”{leg_index} not in self.legs_dic”)

Returns:

Dictionary of ROS2 parameters

Return type:

Dict[str, Any]

lvl1_params()

Returns parameters for all lvl1 nodes to be launched

Returns:

List of ros2 parameter dictionary, one per node.

Return type:

List[Dict]

lvl2_params()

Returns parameters for all lvl2 nodes to be launched

Returns:

List of ros2 parameter dictionary, one per node.

Return type:

List[Dict]

state_publisher_lvl1()

Prepares all nodes meant to publish the state of the robot to external tools.

Along each lvl1 node, it creates:

• One (customized) joint_state_publisher continuously publishing joint angles

• One robot_state_publisher continuously publishing robot TF and description.

Returns:

List of Nodes to be launched (empty if lvl1 is not to be launched)

Return type:

List[Node]

get_node_lvl1(params)

Return type:

Node

Parameters:

params (Dict[str, Any])

get_node_lvl2(params)

Return type:

Node

Parameters:

params (Dict[str, Any])

static limb_ns(limb_number)

Return type:

str

Parameters:

limb_number (int)

lvl1()

Return type:

List[Node]

lvl2()

Return type:

List[Node]

make_levels()

Return type:

List[List[Node]]

motion_stack.api.launch.builder.xacro_path_from_packer(robot_name)

retieves the .urdf/.xacro path in the install share folder of urdf_packer.

Parameters:

robot_name (str) – corresponds to <robot_name>.xacro

Returns:

motion_stack.api.launch.builder.xacro_path_from_pkg(package_name, xacro_path, options=None)

Gets a path from a package, adding options, in view of xacro compilation.

Parameters:

• package_name (str) – Name of the ros2 package

• xacro_path (str) – Path of the file in the package’s shared directory

• options (str | None) – string of options to append to the command

Returns:

path as a string, appended by options

motion_stack.api.launch.builder.command_from_xacro_path(path, options=None)

Creates ROS2 command to compile xacro at launch time.

Return type:

Command

Parameters:

• path (str)

• options (str | None)

motion_stack.api.launch.builder.T = TypeVar(T)

Type:    TypeVar

Invariant TypeVar.

motion_stack.api.launch.builder.get_cli_argument(arg_name, default)

Returns the CLI argument as a string, or default is none inputed. Can be much better optimised, I don’t care.

Return type:

Union[~T, str]

Parameters:

• arg_name (str)

• default (T)

motion_stack.api.launch.default_params module

Provides and explains all parameters to launch the motion stack

motion_stack.api.launch.default_params.default_params = {'add_joints': [''], 'angle_syncer_delta': 0.17453292519943295, 'control_rate': 30.0, 'end_effector_name': '', 'ignore_limits': False, 'joint_buffer': [0.5, 0.0008726646259971648, 0.00017453292519943296, 1.7453292519943296e-05], 'leg_number': 0, 'limit_margin': 0.0, 'mvmt_update_rate': 10.0, 'speed_mode': False, 'start_effector_name': '', 'urdf': ''}

Type:    Dict[str, Any]

Default parameters taken from the python core.

motion_stack.api.launch.default_params.get_xacro_path(robot_name)

retieves the .urdf/.xacro path in the install share folder

Parameters:

robot_name (str) – corresponds to <robot_name>.xacro

Returns:

motion_stack.api.launch.default_params.enforce_params_type(parameters)

enforces types to dic in place

Parameters:

parameters (Dict[str, Any]) – ros2 parameters dictinary

Return type:

None