The Mission Data System framework defines closed-loop control system abstractions from State Analysis including interfaces for state variables, goals, estimators, and controllers that can be adapted to implement a goal-oriented control system. The framework further provides an execution environment that includes a goal scheduler, execution engine, and fault monitor that support the expression of goal network activity plans. Using these frameworks, adapters can build a goal-oriented control system where activity coordination is verified before execution begins (plan time), and continually during execution. Plan failures including violations of safety constraints expressed in the plan can be handled through automatic re-planning.
This version optimizes a number of key interfaces and features to minimize dependencies, performance overhead, and improve reliability. Fault diagnosis and real-time projection capabilities are incorporated. This version enhances earlier versions primarily through optimizations and quality improvements that raise the technology readiness level.
Goals explicitly constrain system states over explicit time intervals to eliminate ambiguity about intent, as compared to command-oriented control that only implies persistent intent until another command is sent. A goal network scheduling and verification process ensures that all goals in the plan are achievable before starting execution. Goal failures at runtime can be detected (including predicted failures) and handled by adapted response logic. Responses can include plan repairs (try an alternate tactic to achieve the same goal), goal shedding, ignoring the fault, cancelling the plan, or safing the system.
This work was done by William K. Reinholtz and David A. Wagner of Caltech for NASA’s Jet Propulsion Laboratory.
This software is available for commercial licensing. Please contact Dan Broderick at
This Brief includes a Technical Support Package (TSP).
Mission Data System Java Edition Version 7
(reference NPO-47804) is currently available for download from the TSP library.
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Overview
The document is a Technical Support Package for NASA's Mission Data System (MDS) Java Edition Version 7, developed by the Jet Propulsion Laboratory (JPL) under the National Aeronautics and Space Administration (NASA). It outlines the framework's purpose, features, and improvements aimed at building goal-oriented closed-loop control systems.
The MDS framework is designed based on the theory of State Analysis, which allows control intent to be expressed through goals that constrain relevant system state variables. This approach enhances clarity and reduces ambiguity compared to traditional command-oriented control systems. The framework facilitates coordination between states and time through activity plans represented as goal networks, which define a timeline for each state variable and synchronize them with a system clock.
Version 7 of the MDS represents a significant refactoring and optimization of the core frameworks, focusing on improving scheduling and execution performance and reliability. Key enhancements include a complete redesign of the goal scheduler, enabling incremental and modular verification and testing. The redesigned interfaces are optimized for ease of adaptation and reliability.
The document highlights several key benefits of the MDS framework, including:
- Explicit Goal Constraints: Goals explicitly constrain system states over defined time intervals, eliminating ambiguity about control intent.
- Achievability Verification: The goal network scheduling and verification process ensures that all goals in a plan are achievable before execution begins.
- Runtime Fault Management: The system can detect goal failures at runtime, including predicted failures, and initiate appropriate responses. These responses may include plan repairs, goal shedding, ignoring faults, canceling plans, or implementing safety measures.
The document also provides contact information for further inquiries, including technical support and additional resources related to the MDS framework. It emphasizes the importance of compliance with U.S. export regulations and notes that the information may contain proprietary content.
Overall, the Technical Support Package serves as a comprehensive guide to the capabilities and advancements of the MDS Java Edition Version 7, showcasing its potential applications in aerospace technology and control systems.
