NASA SBIR 02-1 Solicitation


PROPOSAL NUMBER:02- E2.02-9694 (For NASA Use Only - Chron: 022305 )
SUBTOPIC TITLE: Guidance, Navigation and Control
PROPOSAL TITLE: Intelligent Fault Tolerant Control of Spacecraft

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
Scientific Systems Co Inc
500 West Cummings Park Suite 3950
Woburn , MA   01801 - 6580
(781 ) 933 - 5355

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Jovan Boskovic/Raman Mehra
500 West Cummings Park Suite 3950
Woburn , MA   01801 - 6580
(781 ) 933 - 5355

SSCI, in collaboration with Swales Aerospace, proposes to develop
an Intelligent Fault-Tolerant (IFT) control system to enhance the
performance of spacecraft Attitude Determination and Control
Subsystems (ADCS) in the presence of environmental torque disturbances, sensor noise variation, parametric and/or
structural uncertainties, and low control control authority, and
will be capable of automatically compensating for a loss of
sensors, actuators, or a combination of both through on-line
failure detection/identification, and adaptive control
reconfiguration. In particular, during the Phase I effort we plan
to demonstrate the capability of the proposed IFT-ADCS subject to
two degraded operating conditions that are commonly encountered in satellite missions: (1) Partial or total loss of on-board
gyros, and (2) Partial or total loss of Reaction Wheel Assembly
(RWA) actuators. In the former case, we propose to develop a
scheme based on a well established Interacting Multiple Model
(IMM) estimator for improved rate estimation accuracy and smooth
and robust operation subject to rate swapping (from gyro
measurement to gyroless rate estimator) or high rate slewing. In
the case of RWA failures, Magnetic Torquer Bars (MTB), or
Thrusters, or a combination of both will be employed to
accommodate for the failure. The proposed adaptive
reconfigurable control system will result in substantially
increased spacecraft on-board autonomy that will have a potential
to rescue the entire mission at its early stages despite
unexpected failures of critical components such as gyros, RWA, or
star tracker. Swales Aerospace will provide technical
and commercialization support during all phases of the project.

Higher controller autonomy is one of the major enabling
technologies in the rapidly-growing commercial and military
satellite markets and will result in substantial cost reduction
due to: (i) Reduced human intervention for operation and
maintenance; (ii) Increased reliability and mission lifetime;
(iii) Decreased up-link and down-link bandwidth requirements;
(iv) Reduced testing and implementation costs; and (v) Decreased
software and hardware complexity. Hence the proposed autonomous intelligent fault-tolerant controller design has a great
commercial potential in both civilian and defense applications
including commercial and military satellites, and can also be
applied to aircraft, autonomous underwater and ground vehicles,
"smart" missiles, ships, robots, process control and
manufacturing systems.

The end result of the proposed work will be the
development of a reusable flight code that captures the entire
IFT-ADCS architecture. Either in its entirety or in part, the
individual subsystem of the proposed IFT ADCS can be applied to
both current and future missions. An important part of this
effort will be the design, development, and commercialization of
a software design toolkit for the design and implementation of
IFT-ADCS for spacecraft.

Form Printed on 09-05-02 10:10