NASA SBIR 2004 Solicitation

SMALL BUSINESS CONCERN (Name, E-mail, Mail Address, City/State/Zip, Phone)
Scientific Systems Co Inc
500 West Cummings Park Suite 3000
Woburn, MA 01801-6580
(781)933-5355

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Eliot S.-M. Li
eliot@ssci.com
500 West Cummings Park Suite 3950
Woburn, MA 01801-6580
(781)933-5355

TECHNICAL ABSTRACT (LIMIT 200 WORDS)
In this SBIR project we propose to integrate spacecraft control and vehicle health functions to improve the robustness and productivity of space operations. The main advantages of the proposed approach is that it allows the spacecraft to utilize failed control components with degraded performance to the maximum extent, and to conduct health status test with minimum or no impact on the mission, all in an autonomous manner. The proposed approach is innovative because traditional approaches typically abandon the failed component completely after the first sign of malfunctioning. Putting all the burden on the remaining components wear them down faster and shorten their useful life. Through the integration of accurate health monitoring and control reconfiguration algorithms in a hierarchical architecture, the proposed approach adjust the command signal to the failed component according to its degree of degradation, with the shortfall distributed among the remaining undamaged control components. This results in balanced utilization of all the available resources at all time, and increase the mission life of the spacecraft. During Phase II, the developed algorithms will be integrated into an Autonomous Spacecraft REconfigurable Control System (ASRECS) prototype for NASA testing and evaluation.

POTENTIAL NASA COMMERCIAL APPLICATIONS (LIMIT 100 WORDS)
The health monitoring and control reconfiguration algorithms developed in this Phase I effort for spacecraft control will be beneficial to a wide class space missions. Other control applications subject to model uncertainties due to component failures or system variations can also benefit from the proposed technology. Current and future NASA space missions that can benefit from the proposed technology include Triana, MAXIM, and Kepler. The capability to continue the mission under failure, as well as the cost saving and increased reliability of attitude determination and control system components, will be very attractive from the mission level perspective.

POTENTIAL NON-NASA COMMERCIAL APPLICATIONS (LIMIT 100 WORDS)
The control reconfiguration design for aircraft and UAV has been developed based on the idea of analytic redundancy control concept by leveraging off the remaining control surfaces to produce equivalent force and torque in the direction of the lost ones. However, control methodology that allows the aircraft to ``limp'' home under the underactuated control situation has not been closely addressed. The autonomous underactuated control concept developed herein can potentially be applied to aircraft flight control systems as the backup mode that would significantly increase its safety and reliability beyond its current level.