puppetmaker

Submodules

Classes

class brom_drake.utils.puppetmaker.configuration.Configuration(frame_on_parent: pydrake.multibody.tree.Frame, name: str, frame_on_child: pydrake.multibody.tree.Frame = None, sphere_radius: float = 0.1, sphere_color: numpy.ndarray = None, sphere_mass: float = 0.001, create_actuators_on_init: bool = True)

class brom_drake.utils.puppetmaker.puppet_signature.AllJointSignatures(prismatic: List[brom_drake.utils.puppetmaker.puppet_signature.PuppeteerJointSignature], revolute: List[brom_drake.utils.puppetmaker.puppet_signature.PuppeteerJointSignature])

class brom_drake.utils.puppetmaker.puppet_signature.PuppeteerJointSignature(joint: pydrake.multibody.tree.Joint, joint_actuator: pydrake.multibody.tree.JointActuator)

class brom_drake.utils.puppetmaker.puppet_signature.PuppetSignature(name: str, model_instance_index: pydrake.multibody.tree.ModelInstanceIndex, prismatic_ghost_bodies: List[pydrake.multibody.tree.ModelInstanceIndex], revolute_ghost_bodies: List[pydrake.multibody.tree.ModelInstanceIndex], joints: brom_drake.utils.puppetmaker.puppet_signature.AllJointSignatures)

class brom_drake.utils.puppetmaker.puppetmaker.Puppetmaker(plant: MultibodyPlant, puppet_anchored_to: Frame = None, frame_on_puppet: Frame = None, name: str = None, sphere_radius: float = None, config: Configuration = None)

Description

This class turns a “free body” in Drake into a “puppet” whose pose and orientation can be controlled using 6 actuated joints (3 prismatic and 3 revolute).

This object is used to:

• Add “invisible” actuators for moving a free body (i.e., add_strings_for or add_actuators_for), and

• Control actuate a free body that has been added with the expected “puppet” actuators (i.e., `add_puppet_controller_for)

Important

The 2 functions of the puppetmaker are designed to be used at different times. The add_strings_for or add_actuators_for methods MUST be called BEFORE finalizing the plant. The add_puppet_controller_for method MUST be called AFTER finalizing the plant.

Notes

• The puppet is assumed to be a free body (i.e., it has no existing joints connecting it to the world). After adding the puppet actuators, the puppet will NO LONGER be a free body.

• You must call add_strings_for or add_actuators_for BEFORE finalizing the plant.

add_actuated_prismatic_joint(axis_dimension: int, previous_frame: Frame, next_frame: Frame, joint_name: str) → Tuple[PrismaticJoint, JointActuator]

Description

This method will add an prismatic joint in the direction axis_dimension between previous_frame and next_frame, along with an actuator to control it.

Parameters

axis_dimension: int

The axis to translate in (0 for X, 1 for Y, 2 for Z).

previous_frame: Frame

The frame of the parent side of the joint.

next_frame: Frame

The frame of the child side of the joint.

joint_name: str

The name of the joint we are creating.

Returns

translation_joint_ii: PrismaticJoint

The created prismatic joint.

translation_actuator_ii: JointActuator

The created actuator for the prismatic joint.

add_actuated_revolute_joint(angle_type: RollPitchYawAngle, previous_frame: Frame, next_frame: Frame, joint_name: str) → Tuple[Joint, JointActuator]

Description

This method will add a revolute joint in the direction axis_dimension between previous_frame and next_frame, along with an actuator to control it.

Parameters

axis_dimension: int

The axis to rotate about

add_actuators_for(target_model: ModelInstanceIndex) → PuppetSignature

Description

Creates actuated joints on the object we want to be the “puppet” so that we can control its entire pose. This will be 6 joints:

1. Translation in X

2. Translation In Y

3. Translation In Z

4. Rotation (Roll)

5. Rotation (Pitch)

6. Rotation (Yaw)

Parameters

target_model: pydrake.multibody.tree.ModelInstanceIndex

The model instance index of the puppet to add actuators for.

add_all_actuated_revolute_joints(target_model: ModelInstanceIndex, massless_sphere_indices: List[ModelInstanceIndex]) → List[PuppeteerJointSignature]

Description

This function creates the 3 actuated revolute joints needed to control the orientation of the puppet.

Because the puppet’s orientation is controlled using roll-pitch-yaw angles, the order of the revolute joints will correspond to the standard body rotation order for roll-pitch-yaw (note this is not roll first, then pitch, then yaw).

Notes

This function expects 3 massless sphere inputs. The first sphere in the list should be the one representing the last translation sphere (i.e., the one we should connect the first revolute sphere to.)

add_feedforward_sum_system_for(signature: PuppetSignature, builder: DiagramBuilder) → Tuple[Adder, ConstantVectorSource]

Description

This method will create a simple Adder system to add feedforward inputs to the PID controller output.

add_massless_sphere_to_plant_with_name(name: str, color: ndarray = None) → ModelInstanceIndex

Description

This method adds a sphere with:

• nearly zero mass

• no collision geometry,

• and an associated color

to the Puppeteer’s plant.

The sphere’s name will be assigned by the input to the function.

add_puppet_controller_for(signature: PuppetSignature, builder: DiagramBuilder, Kp: ndarray = None, Kd: ndarray = None) → Tuple[RigidTransformToVectorSystem, PassThrough | None]

Description

This method will create a simple PID controller to actuate the puppet to a desired pose.

Parameters

signaturePuppetSignature

The signature of the puppet to be controlled.

builderDiagramBuilder

The diagram builder to add the controller to.

Kpnp.ndarray, optional

The proportional gain for the PID controller. If not provided, a default value will be used.

Kdnp.ndarray, optional

The derivative gain for the PID controller. If not provided, a default value will be used.

Returns

pose_to_vector_systemRigidTransformToVectorSystem

The system that converts the desired pose to a vector format. This system is what provides the target to the PID controller. You can think of this as the “reference” signal for the controller.

passthrough_systemPassThrough|None

A passthrough system that can be used to provide inputs to the “puppet” if the Puppet contains actuated joints. If the puppet does not contain any actuated joints, then this will be None.

add_strings_for(target_model: ModelInstanceIndex) → PuppetSignature

Description

Adds the necessary actuators for the puppet’s joints.

Parameters

target_model: pydrake.multibody.tree.ModelInstanceIndex

The model instance index of the puppet to add actuators for.

combine_feedforward_and_controller_for(builder: DiagramBuilder, feedforward_adder: Adder, controller: PidController) → Tuple[Adder, ConstantVectorSource]

Description

This method will connect the output of the PID controller to one input of the feedforward adder.

connect_plant_to_controller(builder: DiagramBuilder, controller: PidController, signature: PuppetSignature) → None

Description

Connect the plant to the controller.

create_actuator_demux(signature: PuppetSignature, builder: DiagramBuilder) → Tuple[Demultiplexer, PassThrough | None]

Description

This method creates a demultiplexer to split the actuator inputs to the puppet’s various models.

create_actuator_passthrough_for_puppet_with_actuated_joints(signature: PuppetSignature, builder: DiagramBuilder) → Tuple[PassThrough, PassThrough]

Description

This method creates two passthrough systems: 1. passes the “default” actuator inputs for the puppet’s (default) actuated joints, 2. passes the “puppet” actuator input for puppeteering.

Returns

default_actuator_inputs_passthroughPassThrough

A passthrough system that passes the default actuator inputs for the puppet’s (default) actuated joints.

puppet_actuator_inputPassThrough

A passthrough system that passes the puppet actuator input for puppeteering.

create_ghost_bodies_for_actuators() → Tuple[List[ModelInstanceIndex], List[ModelInstanceIndex]]

Description

This method creates a set of simple spheres which we will use to connect actuators to the “puppet”. We will reuse the simple shape API’s in Brom to create a set of new URDFs that will have (i) no mass, and (ii) no collision geometry.

find_index_of_position_state_in(model_instance_index: ModelInstanceIndex, signature: PuppetSignature) → int | None

Description

This method finds the names of the “position” component for the state of the joint connected to model_instance_index.

find_index_of_velocity_state_in(model_instance_index: ModelInstanceIndex, signature: PuppetSignature) → int | None

Description

This method finds the names of the “velocity” component for the state of the joint connected to model_instance_index.

Parameters

model_instance_index: pydrake.multibody.tree.ModelInstanceIndex

The model instance index of the model to search through.

signature: PuppetSignature

The signature of the puppet being controlled.

rotation_joint_name(target_model: ModelInstanceIndex, rpy_selection: RollPitchYawAngle, remove_puppeteer_prefix: bool = False) → str

Description

This method returns the name of a specific rotation joint created for the puppet.

Parameters

target_model: pydrake.multibody.tree.ModelInstanceIndex

The model instance index of the puppet.

axis_dimension: int

The axis dimension (0, 1, or 2) corresponding to the rotation joint to get the name for.

remove_puppeteer_prefix: bool, optional

If True, the returned joint name will not include the puppeteer prefix. Default is False.

rotation_joint_names(target_model: ModelInstanceIndex, remove_puppeteer_prefix: bool = False) → List[str]

Description

This method returns the names of all rotation joints created for the puppet.

Parameters

target_model: pydrake.multibody.tree.ModelInstanceIndex

The model instance index of the puppet.

remove_puppeteer_prefix: bool, optional

If True, the returned joint names will not include the puppeteer prefix. Default is False.

translation_joint_names(target_model: ModelInstanceIndex, remove_puppeteer_prefix: bool = False) → List[str]

Description

This method returns the names of all translation joints created for the puppet.

Functions

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Variables

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