Blackboard Reference

The blackboard system provides shared memory for inter-behavior communication, storing workflow state and object information that behaviors can read from and write to during execution.

For architecture concepts and usage examples, refer to the main isaac_manipulator_orchestration documentation.

Object Management

The system tracks objects through their life cycle from detection to placement using several interconnected blackboard variables.

Object Info Cache

Variable	Data Type	Description
object_info_cache	Dictionary	Maps object IDs to detected object information, updated throughout the workflow as objects progress through manipulation stages

Stored Information per Object:

Property	Description	Values/Format
Object Properties	Physical attributes and identifiers	Bounding boxes, estimated poses, class IDs, frame names
Object Status	Current state in manipulation pipeline	NOT_READY, SELECTED, READY_FOR_MOTION, IN_MOTION, DONE, FAILED
Drop Poses	Target placement locations	Pose data for where object should be placed

Object ID Tracking Variables

Pipeline variables that manage object progression:

Variable	Purpose	Set By	Used By	Data Type
selected_object_id	Currently selected object for pose estimation	ObjectSelector behavior	PoseEstimation behavior	int
next_object_id	Queue of objects ready for motion planning	PoseEstimation (after successful pose estimation)	MarkObjectAsActive (to transition objects to motion)	deque (queue) containing object IDs
active_obj_id	Object currently undergoing motion execution	MarkObjectAsActive (when popping from next_object_id queue)	MarkObjectAsDone or MarkObjectAsFailed (for clearing)	int

Pose Management

Home Pose

Default robot arm position for recovery and initialization:

Variable	Data Type	Frame	Used By	Description
home_pose	7-element array [x, y, z, qx, qy, qz, qw]	Robot base frame	UpdateDropPoseToHome	Default robot arm position for recovery and fallback scenarios

Drop Pose Variables

Target placement location management:

Variable	Data Type	Source	Set By	Used By	Description
rviz_drop_pose	geometry_msgs/PoseStamped	Interactive RViz marker with 3D gripper manipulation	InteractiveMarker behavior	UpdateDropPoseFromRViz	Interactive RViz-specified drop pose, updated in real-time as users manipulate markers
goal_drop_pose	geometry_msgs/Pose	Active object’s drop pose from object_info_cache; can originate from RViz interactions, action parameters, or home pose fallback	ReadDropPose behavior	Motion planning behaviors (PlanToPose)	Current motion planning target pose

Object Configuration

Status Reporting Variables

The system maintains comprehensive status tracking through dedicated blackboard variables that provide real-time workflow monitoring and completion reporting:

Variable	Purpose	Data Type	Set By	Used By	Description
workflow_status	Overall workflow completion status	int (MultiObjectPickAndPlace.Result enum)	UpdateWorkflowStatus behavior	Action server result determination	Tracks overall workflow outcome: SUCCESS (all objects completed), FAILED (all objects failed), PARTIAL_SUCCESS (mixed outcomes), INCOMPLETE (interrupted), or UNKNOWN (processing ongoing)
workflow_summary	Human-readable progress report	string	ReportGeneration behavior	Action server feedback and logging	Contains detailed status summary counting completed, failed, in-progress, and pending objects with descriptive messages
workflow_feedback_queue	Real-time individual object status updates	collections.deque	MarkObjectAsDone, MarkObjectAsFailed behaviors	Action server feedback loop	Queue of individual object completion/failure messages for immediate user feedback as objects are processed

Supported Objects System

The system maintains a configuration dictionary that defines which objects can be manipulated and links detection classes to manipulation resources:

Variable	Purpose	Data Structure	Used By	Description
supported_objects_config	Main configuration dictionary	Dictionary indexed by Class ID	System initialization	Contains class_id, grasp_file_path, mesh_file_path, object_name - links detection classes to manipulation resources
supported_class_ids	Set of valid class IDs	Set derived from supported_objects_config	FilterDetections	Removes unsupported objects from detection results
mesh_file_paths	Class ID to mesh file mapping	Dictionary created from supported_objects_config	MeshAssigner, Motion planning (PlanToPose, PlanToGrasp), AttachObject	Used for FoundationPose estimation, collision detection, and CUSTOM_MESH object attachment
grasp_reader_manager	Grasp pose data manager	Manager object with YAML file access	ReadGraspPoses	Loads pre-computed grasp poses from YAML files, provides object-specific grasp poses