Executive(s)

1. Executive(s) Life in the Atacama Design ReviewDecember 19, 2003 Nicola Muscettola Vijayakumar Baskaran NASA Ames Research Center NASA Ames Research Center

2. Description and Motivation • Model-Based Executive(s) for LITA • Rover Executive • Instrument Manager • Modules were presented in September 2003 NASA Ames Research Center

3. Mission-level agent Science Planner System-level agents Science Executive Rover Architecture using IDEA Operator Interface Offboard Telemetry Router Mission Planner Waypoints IDEA Mission Executive Mission Executive Status Waypoint Curvature, Speed & Time Curvature, Speed & Time Onboard Navigator Health Monitor Stop TerrainEvaluation Odometry Stereo Mapper State Estimator Vehicle Controller Status Status Sensors Images NASA Ames Research Center

4. Description and Motivation • Model-Based Executive(s) for LITA • Rover Executive • Instrument Manager • Modules were presented in September 2003 • Motivating System Requirements: 3.1, 4.4, 5.4.1 (but what does that mean really?), 5.5, 6.0 NASA Ames Research Center

5. Key Requirements • Rover Executive: provide goal-driven commanding for high-level traverse and science operations • “Go to waypoint” and “Perform Detailed Investigations” • Instrument Manager: allows single goal commanding • “Do mosaic” instead of sequence of individual snapshots • Executive invokes planner(s) if necessary to optimize course of action • Executive translates between abstract goals and low-level commands • Executive issues commands and responses as a consequence of internal (synchronous) or external (asynchronous) events • Executive must be robust to wide range of faults (to be defined) • Executive must guarantee response within required time limits NASA Ames Research Center

6. Software Organization Science Interface Rover Interface Telemetry Goals Health Monitor Telemetry Manager SciencePlanner Mission Planner Measurements Faults Plans Plans State State Plans Measurements StateObserver Rover Executive State(All) Positions Stop Waypoints Actions Instrument Manager Position Estimator Mapper Navigator Odometry Curvature& Speed Far-field Evaluator Near-field Detector Vehicle Controller Instrument Controllers Images Measurements Data Images Proprioception& Sun Image Commands Commands NASA Ames Research Center

7. Design Considerations • Informing Design Principle: • The logic of execution and recovery shall be fully inspectable • A model-based approach combines a declarative model, a general-purpose plan synthesis engine and heuristics • A model-based approach is expected to allow quick incremental encoding of new recoveries from failure conditions as they are discovered • Metrics: • Coverage of failure conditions • Reaction time (as a function of model complexity) • The design is influenced from Remote Agent and Gromit rover experience • Reimplementation of the DS1 Executive as a model-based system vs the old procedural Executive in ESL • Gromit (ATRV Junior) rover executive reimplement PRS-based executive from LAAS/CNRS NASA Ames Research Center

8. Technical Approach • Multiple executives (Rover Executive and Instrument Manager) vs single executive • Coupling between rover components • Reaction time • Currently focusing on single executive (consistent with Dave’s architecture concept) • Modeled constraints can be switched on or off to support direct teleoperation modes (monitored mode of requirements 6.0) NASA Ames Research Center

9. Implementation Issues • Prototype tests • Simulator • Mission Simulator Facility? Not clear if it is usable for real-time simulation • Rover • Multi-day scaled-down autonomous traverse with Gromit • Expected timeframe: April 2004 • Risks • Complexity of incremental modeling Mitigations: full engagement of trained Ames personnel, training, better modeling tools/languages • Reaction latency Mitigations: faster planning framework (new EUROPA), use of procedural task expansion (TDL) • Issues • Relation of executive to health monitoring and telemetry server. External modules or internal modules? • What happens to executive during hybernation? Current design assumes it is always “active”, i.e., capable of reacting. Is this reasonable? • Schedule issues: need to firm up ASAP instrument models, message/command dictionary, mission operations concept. NASA Ames Research Center