Intelligent Fault Tolerant Control of Spacecraft

SSCI, in collaboration with Swales Aerospace, proposes to developan Intelligent Fault-Tolerant (IFT) control system to enhance theperformance of spacecraft Attitude Determination and ControlSubsystems (ADCS) in the presence of environmental torque disturbances, sensor noise variation, parametric and/orstructural uncertainties, and low control control authority, andwill be capable of automatically compensating for a loss ofsensors, actuators, or a combination of both through on-linefailure detection/identification, and adaptive controlreconfiguration. In particular, during the Phase I effort we planto demonstrate the capability of the proposed IFT-ADCS subject totwo degraded operating conditions that are commonly encountered in satellite missions: (1) Partial or total loss of on-boardgyros, and (2) Partial or total loss of Reaction Wheel Assembly(RWA) actuators. In the former case, we propose to develop ascheme based on a well established Interacting Multiple Model(IMM) estimator for improved rate estimation accuracy and smoothand robust operation subject to rate swapping (from gyromeasurement to gyroless rate estimator) or high rate slewing. Inthe case of RWA failures, Magnetic Torquer Bars (MTB), orThrusters, or a combination of both will be employed toaccommodate for the failure. The proposed adaptivereconfigurable control system will result in substantiallyincreased spacecraft on-board autonomy that will have a potentialto rescue the entire mission at its early stages despiteunexpected failures of critical components such as gyros, RWA, orstar tracker. Swales Aerospace will provide technicaland commercialization support during all phases of the project.