Autonomous Vehicle Command Language (AVCL)

1. Autonomous Vehicle Command Language (AVCL) CDR Duane Davis, USN 18 April 2006

2. Problem Area: Dissimilar Autonomous Vehicle (AV) Incompatibility • Examples • Homogeneous vehicle system: Swarming • Programmed compatibility: CJTFEX 04-2 Coordinated MCM Vehicle-specific data formats and mission planning systems preclude effective coordination in multi-vehicle systems and hinder the design of such systems. To date, the preponderance of multi-vehicle research has assumed inherent compatibility: homogeneous vehicle systems or explicitly programmed compatibility.

3. AVCL Support AAV 1 AAV 2 AUV 1 AAV 1 AUV 2 AAV 2 ASV 2 ASV 1 ASV 1 ASV 2 AUV 2 AUV 1 Support Support Support Support Support Support Proposed Solution: A Common AV Data Model • Common Data Format: (e.g., AVCL): • Mission Specification (tasking) • Communications • Mission Results • Automated Conversions • AVCL to Vehicle-Specific • Vehicle-Specific to AVCL • Ultimate Goals • Facilitate interoperability between dissimilar vehicles (including legacy) • Support pre-, mid-, and post-mission data requirements • Provide other vehicles and human operators intuitive and efficient data access

4. Research Subtasks • Exemplar Data Model Definition • Task-Level Behavior Set Determination • XML Schema Design • Included data: • Mission Specification (tasking) • Mission Results • Communications (message set) • Data Conversions • AVCL to Vehicle-Specific • Vehicle-Specific to AVCL • AVCL Declarative to AVCL Task-Level • AVCL Task-Level to AVCL Declarative • Data Model Use to Facilitate AV Control • Integration into a Multi-Layer Architecture

5. Scripted Mission Specification SetPosition • Task-Level Behaviors • Minimum Requirements to Capture Arbitrary Tasking • Behavior Activation and Termination Criteria • Scripting • Atomic Task-Level Behaviors • Sequential Execution • Potential Parallelism MakeSpeed MakeDepth Waypoint MakeAltitude Waypoint ObtainGPS Waypoint Quit

6. Declarative Goal-Based Mission Specification • 14 Predefined Goal Types • Finite State Machine (FSM) • States Represent Individual Goals • Transitions Executed upon Goal Success or Failure Mission Start Search Area A Fail Succeed Sample Environment in Area A Search Area B Succeed or Fail Fail Succeed Rendezvous with UUV-2 in Area C Succeed or Fail Mission Complete

7. Task Level Commands Vehicle-Specific Languages AVCL Translations External C2 Systems • AVCL to Vehicle-Specific Data • XSLT (text) • Vehicle-Specific XML (binary) • Vehicle-Specific Data to AVCL • Context Free Grammars (text) • Vehicle-Specific XML (binary) • Artificial Intelligence • Planning and Search • Case-Based Reasoning • Bayesian Reasoning • Business Objects • Command and Control Information Exchange Data Model (C2IEDM) • AVCL Declarative Tasking C2IEDM Business Objects AVCL Mission Goals and Constraints Rules & Templates Planner CFGs or Vehicle-Specific XML XSLT and Vehicle-Specific XML

8. Vehicle-Specific Script AVCL Script XSLT Stylesheet Translation from AVCL to Text-Based Vehicle-Specific Formats • AVCL to Text—Direct generation with XSLT • Exemplar Translations • AVCL to Phoenix UUV • AVCL to ARIES UUV • AVCL to Seahorse UUV • AVCL to REMUS UUV

9. Why? Inability to Update Variable Values Requirement to Maintain Behavior Parameters for Parallel Execution How? Use Template Parameters Explicitly Controlled Iteration A Mutable Variable Pattern for XSLT begin XSLT processing variable B = sequential list of task-level behaviors apply template for B1 with default parameters d1 to dn end XSLT processing begin template for task-level behavior Bi with parameters p1 to pn for k = 1 to n variable vk if Bi updates pk vk = new_pk else vk = pk generate required output for Bi apply template for Bi+1 with parameters v1 to vn end template

10. Vehicle-Specific XML Vehicle-Specific XML Vehicle-Specific Binary Custom Serializer XSLT Stylesheet AVCL Data XSLT Stylesheet Custom Reader Translation from AVCL to Binary Vehicle-Specific Formats and Vice Versa • AVCL to Binary • Generate vehicle-specific XML with XSLT • Serialize to binary • Binary to AVCL • Read from binary to vehicle-specific XML • Generate AVCL with XSLT • Exemplar Implementation • AVCL to Joint Architecture for Unmanned Systems (JAUS) Messages • JAUS Messages to AVCL Vehicle-Specific Binary AVCL Script

11. Binary JAUS-XML JAUS XML Schema XSLT Reader Serializer XML AVCL XSLT JAXB Programming Object

12. Parse as a Context Free Language (CFL) Chomsky Normal Form (CNF) Context Free Grammar (CFG) Cocke-Younger-Kasami (CYK) Parsing Algorithm Yields a Binary Parse Tree Translate Parse Tree to AVCL Depth First Traversal Template-Based Translation of Individual Parse Nodes CFG Serves the Same Role as an XML Schema Parser/Translator Serves the Same Role as an XSLT Stylesheet Mission LaunchCmd MissionMdl MissionEnd WaypointCmd SurfaceCmd RendezvousCmd Translation of Vehicle-Specific Text Formats to AVCL Example Chomsky Normal Form Rules: Mission -> LaunchCmd + MissionMiddle Mission -> LaunchCmd + MissionEnd MissionMiddle -> WaypointCmd + MissionMdl MissionMiddle -> SurfaceCmd + MissionMdl MissionMiddle -> WaypointCmd + MissionEnd MissionMiddle -> SurfaceCmd + MissionEnd MissionEnd -> WaypointCmd + RendezvousCmd MissionEnd -> SurfaceCmd + RendezvousCmd Example (Partial) Parse Tree:

13. Inter-Area Transit Best-First (A*) Search Goal Accomplishment Planning Trivial Goal Types MonitorTransmissions Reposition Others Require Area Coverage (Search) Decision-Tree Plan-Type Selection Parameterized Preplanned Patterns for Regularly Shaped Operating Areas Planner-Generated (A*, Hill-Climbing, Iterative Improvement) for Irregularly Shaped Areas Translation of Declarative Missions to Task-Level Behavior Scripts

14. Inference of Declarative Missions from Task-Level Behavior Scripts • Case Based Reasoning • 14 Weighted Characteristics on the Scale (0..1) • Comparison Against Known Recall Set Instances • Probabilistic Reasoning (Naïve Bayes) • 12 Boolean Characteristics • Independent Conditional Probabilities

15. Multi-Layer AV Control Architectures Hierarchical Hybrid Relationship to AVCL Declarative Mission Scripted Mission Rational Behavior Model (RBM) Three-Level Hybrid Architecture Strategic Level: Ship CO Tactical Level: Watch Officers Execution Level: Watch Standers RBM vs AVCL: Strategic Level: Declarative Mission Tactical Level: Behavior Script Execution Level: Individual Commands AVCL Integration in a Multi-Layer AV Control Architecture

16. Features Augments Existing Vehicle Control Software Translation to Vehicle-Specific Data Format at Lowest Level AVCL Mission Construct Reliant Minimal Modification to Existing Vehicle Controller Communications Model Pull—Higher Levels Query Lower Levels Push—Higher Levels Command Lower Levels Push—Lower Levels Provide Unrequested Information The Extended Rational Behavior Model Extended Rational Behavior Model Controller Strategic Level Declarative AVCL Mission Agenda Control High-Level World Model Goal Planner Status Query Script Status Task-Level Behavior Script Tactical Level Mid-Level World Model Script Control Task-Level Behavior Translator Command Flow Vehicle-Specific Command Command Status Status Query Implied Data Visibility Optional Communications Execution Level (existing vehicle controller) State and Sensor Data

17. Questions