This software implements a real-time access control protocol that is intended to make all connected users aware of the presence of other connected users, and which of them is currently in control of the system. Here, “in control” means that a single user is authorized and enabled to issue instructions to the system.
The software also implements a goal scheduling mechanism that can detect situations where plans for the operation of a target system proposed by different users overlap and interact in conflicting ways. In such situations, the system can either simply report the conflict (rejecting one goal or the entire plan), or reschedule the goals in a way that does not conflict.
The access control mechanism (and associated control protocol) is unique. Other access control mechanisms are generally intended to authenticate users, or exclude unauthorized access. This software does neither, and would likely depend on having some other mechanism to support those requirements.
This work was done by Andrew H. Mishkin, Daniel L. Dvorak, David A. Wagner, and Matthew B. Bennett 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).
Two Mechanisms to Avoid Control Conflicts Resulting from Uncoordinated Intent
(reference NPO-47732) is currently available for download from the TSP library.
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Overview
The document is a Technical Support Package from NASA, specifically referencing NPO-47732, which discusses mechanisms to avoid control conflicts arising from uncoordinated intent in aerospace operations. It emphasizes the need for autonomy in systems, particularly in environments where communication delays can hinder timely decision-making. The document outlines several key architectural qualities and strategies aimed at enhancing the safety and operability of flight software.
One of the primary focuses is on the architectural approach, which is designed to create efficient, flexible, and verifiable solutions. The document highlights that good systems and software architecture serves as a robust defense against incidental complexity, suggesting that a well-structured architecture can significantly improve operational effectiveness. It emphasizes the importance of principles in architecture, such as ensuring that all control decisions are based on estimated states, desired states, and behavioral models.
The document also discusses the concept of managed control authority, which involves implementing access controls to manage potential conflicts. While these controls can provide warnings about conflicts, they are not equipped to handle long-running or scheduled control activities. Therefore, the need for goal-oriented coordination is underscored, where multiple goals must be integrated into a single coordinated plan. New goals must either merge into the executing plan or be rejected to maintain operational coherence.
Additionally, the document introduces the "Time Line Concept," which utilizes state variables to provide access to timelines, allowing for better management of continuous and discrete variables over time. This concept aids in comparing past actions with future plans, enhancing situational awareness.
Overall, the document serves as a comprehensive guide to understanding the complexities of autonomy in aerospace systems, providing insights into architectural strategies, control mechanisms, and the importance of coordination in achieving safe and effective operations. It is a valuable resource for those involved in aerospace technology and automation, offering a framework for addressing the challenges posed by uncoordinated intents in dynamic environments.
