Version 2 of Closed Loop Execution and Recovery (CLEaR) has been developed. The previous version was reported in “Software for Automation of Real-Time Agents” (NPO-21040), NASA Tech Briefs, Vol. 26, No. 7 (July 2002), page 34. To recapitulate: CLEaR is an artificial intelligence computer program for use in planning and execution of actions of autonomous agents, including, for example, Deep Space Network (DSN) antenna ground stations, robotic exploratory ground vehicles (rovers), robotic aircraft (UAVs), and robotic spacecraft.

CLEaR automates the generation and execution of command sequences, monitoring the sequence execution, and modifying the command sequence in response to execution deviations and failures as well as new goals for the agent to achieve. The development of CLEaR has focused on the unification of planning and execution to increase the ability of the autonomous agent to perform under tight resource and time constraints coupled with uncertainty in how much of resources and time will be required to perform a task. This unification is realized by extending the traditional three-tier robotic control architecture by increasing the interaction between the software components that perform deliberation and reactive functions. The increase in interaction reduces the need to replan, enables earlier detection of the need to replan, and enables replanning to occur before an agent enters a state of failure.

This program was written by Forest Fisher, Tara Estlin, Daniel Gaines, Steve Schaffer, Caroline Chouinard, Barbara Engelhardt, Colette Wilklow, Darren Mutz, Russell Knight, Gregg Rabideau, and Steve Chien of Caltech, and Reid Simmons and David Apfelbaum of CMU for NASA’s Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at under the Software category.

This software is available for commercial licensing. Please contact Karina Edmonds of the California Institute of Technology at (818) 393-2827. Refer to NPO-30745.

This Brief includes a Technical Support Package (TSP).

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NASA Tech Briefs Magazine

This article first appeared in the September, 2005 issue of NASA Tech Briefs Magazine.

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