1. Automated Parsing and Conversion Of Vehicle-specific Data into Autonomous Vehicle Control Language using Context-Free Grammars and XML Data Binding CDR Duane Davis, USN

2. Outline Autonomous Vehicle Command Language (AVCL)—What and Why? Context-Free Grammars (CFG) and Vehicle- Specific Data Formats Parsing Vehicle-Specific Documents Transformation of Parsed Vehicle-Specific Data into AVCL Specific Vehicle Implementation Summary

3. What (Why) is AVCL? Autonomous Vehicle (AV) Ontology Vehicle Independent Schema-Governed Extensible Markup Language (XML) Automated Conversions AVCL to Vehicle-Specific Vehicle-Specific to AVCL Ultimate Goals Facilitate Interoperability Support Pre-, Mid-, and Post- Mission Data Requirements Provide Intuitive Data Access AVCL AAV 1 Support AUV 2 AGV 2 AAV 2 AUV 1 AGV 1 AUV 2 AGV 2 AAV 2AAV 1 Support AGV 1 AUV 1

4. AVCL Organization Mission Specification (Tasking) Scripted Behaviors Declarative Goals Mission Results Synchronous Telemetry Control Orders Asynchronous Event Log Communications

5. Mission Specification Scripting Atomic Task-Level Commands Sequential Execution Potential Parallelism Declarative Goals Finite State Machine (FSM) States Represent Individual Goals Transitions Executed upon Goal Success or Failure A Scripted AVCL AUV Mission:

6. AVCL Mission Goals and Constraints Task Level Commands Vehicle-Specific Languages Planners Rules & Templates XSLT / XML Data Binding AVCL Translations AVCL to Vehicle-Specific Data XSLT XML Data Binding Vehicle-Specific Data to AVCL Context Free Grammars XML Data Binding Declarative to Scripted AVCL A* Search GraphPlan Scripted to Declarative AVCL Case-Based Reasoning Bayesian Reasoning CFGs AVCL to Vehicle-Specific Data XSLT XML Data Binding Vehicle-Specific Data to AVCL Context Free Grammars XML Data Binding Declarative to Scripted AVCL A* Search GraphPlan Scripted to Declarative AVCL Case-Based Reasoning Bayesian Reasoning

7. CFGs and Vehicle-Specific Data Vehicle-Specific Data Formats Are: Not XML (cannot use XSLT for translations) Rigorously Defined Unambiguous Context Free Languages (CFL) Can be Generated by Context Free Grammars (CFG) A Seahorse AUV Station Keeping Order: Start_Order : Station_Keep_Order Scheduling_Info_Is_Timed : True Destination_Latitude : 33.0 Degrees Destination_Longitude : -122.5 Degrees Until_when : 90 Minutes Transit_Altitude : 15 Meters Loiter_Depth : 15 Feet

8. Context Free Grammar Definition Terminals (the alphabet) Reserved Words Numbers Variables Represent Substrings Productions: is a Variable is a Sequence of Variables and Terminals Means “Produces” Define how Variables Expand into Instances Formal CFG Definition: is a Set of Variables is a Set of Terminals is a Set of Productions is a Set of Start Variables A Simple Example (produces balanced parentheses):

9. Chomsky Normal Form (CNF) No Useless Symbols All terminals appear in at least one valid CFL string All variables are used in the derivation of at least one valid CFL string NoεProductions ε is a “null” (no literal) Productions of the form where contains ε Production Rule Form Restrictions where,, and are variables where is a variable and is a terminal

10. CFG-Based Parsing Cocke-Younger-Kasami (CYK) Algorithm Uses CNF Production Rules Bottom up Parser Organizes Data as a Binary Parse Tree “-121.7” “-33.5”“15.0” “Waypoint” Double WaypointTkn LatLongPosition3DCommand

11. Parse Tree Translation Depth-First Parse Tree Traversal In-Order Traversal of the Source Document Multiple Traversals—Symbol Table Generation Template-Based AVCL Generation Applied at Command Node Level Full Traversal Unnecessary Analogous to XSLT Transformation of XML In Order vs. Arbitrary Order Input Document Traversal Arbitrary Order vs. In Order Output Document Generation

12. Parse Tree Conversion Generated AVCL Script Mission: <LatitudeLongitude latitude="-33.5" longitude="-121.7"/>... “-121.7” “-33.5”“15.0” Double LatLong Position3D “Waypoint” WaypointTkn Command CommandLst Mission CommandLst …… LaunchCmd …… …… CommandLst Mission Command “Waypoint” WaypointTkn “-121.7” “-33.5”“15.0” Double LatLong Position3DCommandLst ……

13. Vehicle Implementations NPS ARIES Sequentially Executed Waypoints 11 Double-Precision Numbers Implementation CFG 1 Unary ( ) Production 14 Binary ( ) Productions NPS Phoenix Sequentially Executed Script Commands (34) Mixed Text and Numbers Implementation CFG 22 Unary Productions 39 Binary Productions NAVO Seahorse Command Set Sequentially Executed Script Commands (4) Start and End Commands Mixed Text and Numbers Implementation CFG 47 Unary Productions 136 Binary Productions WHOI REMUS Command Set Locations Sequential Objectives (14) Mixed Text and Numbers Implementation CFG 40 Unary Productions 40 Binary Productions

14. Questions?