systems¶

Submodules¶

Classes¶

class brom_drake.systems.abstract_list_selection_system.AbstractListSelectionSystem(index: int, output_type: type = <class 'pydrake.math.RigidTransform'>, output_port_name: str = 'element_out')[source]¶

Description

This System receives selects a single element from an AbstractValue that contains a list. The index of the element to select is specified at construction time.

Diagram

The LeafSystem’s input and output ports can be illustrated with the following block:

                |---------------|
list_in ------->|               |
(List)          | List          |
                | Selection     | ----> element_out
                | System        |       (Element Type)
                |               |
                |---------------|

CalcOutputElement(context: Context, output: AbstractValue)[source]¶

Description

This callback function computes the selected element from the input list.

class brom_drake.systems.end_effector_wrench_calculator.EndEffectorWrenchCalculator(plant, end_effector_frame)[source]¶

Description

A simple system which takes as input joint torques and outputs the corresponding wrench applied to the end-effector.

Diagram

The system can be illustrated with the following block:

                    ---------------------------------
                    |                               |
                    |                               |
                    |                               |
joint_positions --> |  EndEffectorWrenchCalculator  | ---> end_effector_wrench
joint_angles -----> |                               |
joint_torques ----> |                               |
                    |                               |
                    |                               |
                    ---------------------------------

class brom_drake.systems.pose_composition.PoseCompositionSystem[source]¶

Description

This LeafSystem receives two Pose inputs (i.e., AbstractValue objects containing RigidTransform values) and returns the composition of the two poses (i.e., an AbstractValue containing a RigidTransform value).

Diagram

The LeafSystem’s input and output ports can be illustrated with the following block:

                    |---------------|
pose_AB ----------->|               |
(RigidTransform)    | Pose          |
                    | Composition   | ----> pose_AC
pose_BC ----------->| System        |       (RigidTransform)
(RigidTransform)    |               |
                    |---------------|

CalcOutputPose(context: Context, output: AbstractValue)[source]¶

Description

This callback function computes the composed pose, pose_AC, from the two inputs pose_AB and pose_BC.

class brom_drake.systems.rpy_integrator.RPYIntegrator[source]¶

Description

A system that integrates roll, pitch, and yaw velocity signals to produce roll, pitch, and yaw position estimates without angle wrap-around.

This system is useful when you want to track cumulative rotation angles beyond the typical [-π, π] range, allowing for unbounded angle tracking (e.g., roll = 10π is valid).

Notes

This system integrates the time derivatives of RPY angles (ṙoll, ṗitch, ẏaw).
If you have body-frame angular velocities (ωx, ωy, ωz), you must convert them to RPY rates first using the appropriate transformation matrix.
Initial conditions can be set through the context’s continuous state.

Example

from pydrake.all import DiagramBuilder
import numpy as np

builder = DiagramBuilder()

# Create the integrator
rpy_integrator = builder.AddSystem(RPYIntegrator())

# Connect current RPY to set initial state
# builder.Connect(current_rpy_source.get_output_port(),
#                 rpy_integrator.get_input_port(0))

# Connect velocity source to integrator
# builder.Connect(velocity_source.get_output_port(),
#                 rpy_integrator.get_input_port(1))

CalcOutput(context, output)[source]¶: Output the current integrated RPY values.

DoCalcTimeDerivatives(context, derivatives)[source]¶: Calculate the time derivatives (which are just the input velocities).

SetDefaultState(context, state)[source]¶: Set the default initial state for the integrator from the RPY input port.

get_rpy_input_port()[source]¶: Returns the input port for current RPY values (used to set initial state).

get_rpy_velocity_input_port()[source]¶: Returns the input port for RPY velocity values.

Functions¶

brom_drake.systems.named_vector_selection_system.define_named_vector_selection_system(all_element_names: List[str], sequence_of_names_for_output: List[str]) → AffineSystem[source]¶

Description

This method creates an Affine System that will receive as input a vector where each element is named according to all_element_names and returns an output vector that selects only the elements specified in desired_inputs.

Parameters

namestr: The name of the system to be added.
all_element_namesList[str]: The list of all element names in the input vector.
desired_inputsList[str]: The list of desired element names to be selected for output.

Returns

AffineSystem: The created NamedVectorSelectionSystem.

Variables¶

(None found)