Motivated by several accidents, attitude control of a spacecraft subject to faults/failures has gained considerable attention in a wider range of aerospace engineering and academic communities. This paper is concerned with industrial practices and theoretical approaches for fault tolerant control (FTC) and fault detection and diagnosis (FDD) in spacecraft attitude control system. An overview on recent development of spacecraft attitude FTC system design is presented. The basis of a FTC system is introduced. The existing engineering FTC techniques and theoretical methodologies, including their advantages and disadvantages, are discussed. Moreover, closely associated with the reliability-relevant issues, recent progress in attitude FTC design strategies is reviewed. A brief review of some open problems in the general area of spacecraft attitude control design subject to components faults/failures is further concluded.

A Review on Recent Development of Spacecraft Attitude Fault Tolerant Control System

This survey of model-based fault diagnosis focuses on those methods that are applicable to aerospace systems. To highlight the characteristics of aerospace models, generic non-linear dynamical modelling from flight mechanics is recalled and a unifying representation of sensor and actuator faults is presented. An extensive bibliographical review supports a description of the key points of fault detection methods that rely on analytical redundancy. The approaches that best suit the constraints of the field are emphasized and recommendations for future developments in in-flight fault diagnosis are provided.

/pdf/model-based-fault-diagnosis-for-aerospace-systems-a-survey-jpkifgdebi.pdf

Model-based fault diagnosis for aerospace systems: a survey:

A survey of fault-tolerant controllers based on safety-related issues

This paper investigates the velocity-measurement-free feedback control problem associated with attitude tracking for a rigid spacecraft in the presence of both actuator failures and actuator saturation. The decreased reaction torque fault and the increased bias torque fault in the reaction wheel are handled. By using only the measurable attitude, a terminal sliding-mode-based observer is developed to reconstruct all the states of the attitude system in finite time. With the reconstructed information, a novel attitude tracking controller is developed. A Lyapunov analysis shows that the desired attitude trajectories are followed even in the presence of external disturbances. The key features of the proposed control approach are that it is independent from the knowledge of actuator faults and fault-tolerant control is achieved without the need of angular velocity. The attitude tracking performance using the proposed strategy is evaluated through a numerical example.

Fault-Tolerant Tracking Control of Spacecraft with Attitude-Only Measurement Under Actuator Failures

A fault-tolerant control approach without rate sensors is presented for the attitude stabilization of a satellite being developed. External disturbances, reaction wheel faults, actuator saturation, and unavailable angular velocity are addressed. A sliding-mode observer is proposed by using attitude feedback only, and the unavailable angular velocity is estimated by this observer in finite time. Using the attitude and the estimated velocity, another sliding-mode observer is proposed to reconstruct actuator faults and disturbances. It is proven that reconstruction with zero observer error is achieved in finite time. With the reconstructed value, a velocity-free controller is then developed to asymptotically stabilize the attitude. Simulation results are also provided to verify the effectiveness of the proposed approach.

Fault-Tolerant Attitude Stabilization for Satellites Without Rate Sensor

A method for detecting faults in the navigation and control system of deep space satellites is presented. A new method for computing the probability of a fault given multiple different types of residuals processors is presented. The method uses the Shiryayev sequential probability ratio test to estimate the probability of the presence of a fault signal given the residuals generated from either parity relationships or fault detection filters, a fault map of the impact of each fault signal on the residuals, and an adaptive fault estimation scheme that enables processing with fewer residuals. This new methodology is applied to the detection of the fault signals in the attitude control system and navigation system of deep space satellites. First a sensor fusion process is presented for blending star tracker data, gyro data, accelerometer data, and information from the vehicle control system to form the best estimate of the navigation state. Then a set of fault detection filters are developed that detect and uniquely identify faults in each of the sensors or actuators. Decision-making is handled through the sequential processing. Simulation results for a single-satellite system are presented.

Fault Detection and Isolation for Deep Space Satellites

A method for detecting failures in the navigation and control system of deep space satellites is presented. First a sensor fusion process for blending star tracker data, gyro data, accelerometer data, and information from the vehicle control system to form the best estimate of the navigation state is presented. Then a set of fault detection filters are developed that detect and uniquely identify failures in each of the estimation processes. Decision making is handled through the sequential processing. Simulation results for a single satellite system are presented.

James Sharp

Papers

Fault Detection and Isolation for Deep Space Satellites

Fault Detection for Deep Space Satellites