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

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

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

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

NASA Ames Research Center 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

Software Organization Science Interface Rover Interface Telemetry Goals Science Planner Mission Planner Health Monitor Telemetry Manager Measurements Plans Plans Faults State State Plans Measurements Rover Executive State Observer State (All) Positions Waypoints Stop 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

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

NASA Ames Research Center 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

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