Download or read book A Model based Fault Recovery for the Attitude Control Subsystem of a Satellite Using Magnetic Torquers written by Jessica Nathalia Parra Bernal and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interest in small satellites for scientific missions and Earth observations has been increasing steadily in recent years and magnetic torquers have been found attractive as suitable choice of actuators for the purpose of attitude control. Magnetic torquers are commonly used for momentum desaturation of reaction wheels, damping augmentation in gravity gradient stabilized spacecraft. and reorientation of the spin axis in spin-stabilized spacecraft. Furthermore, their use as sole actuators for 3-axis stabilization of satellites in Low-Earth Orbit (LEO) has also been proven effective and advantageous when compared to other types of actuators. The autonomy of complex dynamical systems that are vulnerable to failures has been an important topic of research during the past few years. Particularly, in aerospace applications, where several constraints such as telemetry and hardware redundancy limitations make the management of on-board problems, a difficult task for ground control. With this in mind, an autonomous recovery from faults in magnetic torquers in LEO satellites constitutes the main focus of the work investigated in this dissertation. A self-recovery mechanism, which extends the capabilities of the attitude control subsystem to operate under the presence of actuator faults is developed. The solution generated takes into account the management of the control authority in the system by taking advantage of the non-faulty actuators. In other words, the recovery mechanism that is proposed in this thesis does not utilize hardware redundancy as the existing actuators are used to perform the required control action. The effects of the delay in initiating the recovery solution, the presence of noise in the magnetic field measurement, and the responses of the system that is recovered from concurrent faults are also investigated through numerical simulations. These simulations are carried out by using a model that includes relevant environmental disturbances and a realistic model of the geomagnetic field. A reduction in the average steady state error is obtained in response to and due to the application of the proposed recovery mechanism, which is applicable to the system even in the presence of fault detection delays, presence of noise in the magnetic field measurement and concurrent faults.
Download or read book Fault Diagnosis of Nonlinear Systems Using a Hybrid Approach written by Ehsan Sobhani-Tehrani and published by Springer Science & Business Media. This book was released on 2009-06-22 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theincreasingcomplexityofspacevehiclessuchassatellites,andthecostreduction measures that have affected satellite operators are increasingly driving the need for more autonomy in satellite diagnostics and control systems. Current methods for detecting and correcting anomalies onboard the spacecraft as well as on the ground are primarily manual and labor intensive, and therefore, tend to be slow. Operators inspect telemetry data to determine the current satellite health. They use various statisticaltechniques andmodels,buttheanalysisandevaluation ofthelargevolume of data still require extensive human intervention and expertise that is prone to error. Furthermore, for spacecraft and most of these satellites, there can be potentially unduly long delays in round-trip communications between the ground station and the satellite. In this context, it is desirable to have onboard fault-diagnosis system that is capable of detecting, isolating, identifying or classifying faults in the system withouttheinvolvementandinterventionofoperators.Towardthisend,theprinciple goal here is to improve the ef?ciency, accuracy, and reliability of the trend analysis and diagnostics techniques through utilization of intelligent-based and hybrid-based methodologies.
Download or read book CubeSat Attitude Control Utilizing Low power Magnetic Torquers a Magnetometer written by Donald B. Mentch and published by . This book was released on 2011 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: The CubeSat Project has lowered development time and costs associated with university satellite missions that conform to their 10 centimeter cube design specification. Providing attitude control to a spacecraft, of such small volume, with a very limited power budget has been a challenge around the world. This work describes the development of an attitude control system based on a very low-power magnetic torquer used in conjunction with a magnetometer. This will be the first flight use of this torquer which is composed of a hard magnetic material wrapped inside of a solenoid. By discharging a capacitor through the solenoid, the magnetic dipole moment of this permanent magnet can be reversed. The completed attitude control system will make the first use of the low-power magnetic torquer to arrest satellite tip-off rates. It will then make the first known use of a dual axis magnetic dipole moment bias algorithm to achieve three-axis attitude alignment. The complete system is standalone for high inclination orbits, and will align the spacecraft to within 5 degrees of ram, nadir, and local vertical, without any requirement for attitude determination. The system arrests tip-off rates of up to 5° per second (in all 3 axes) for a satellite in a 600 kilometer polar orbit expending 0.56 milliwatts of power. Once in the proper alignment, it utilizes 0.028 milliwatts to maintain it. The system will function for low inclination orbits with the addition of a gravity boom. The system utilizes the magnetometer to calculate spacecraft body rates. This is the only known use of a magnetometer to directly measure spacecraft body rates without prior knowledge of spacecraft attitude.
Download or read book Advanced Attitude Control of Satellite written by Bing Xiao and published by Springer Nature. This book was released on with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Attitude Dynamics and Control of Satellites with Fluid Ring Actuators written by Nona Abolfathi Nobari and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Successful mission of a satellite depends on maintaining a fixed orientation with respect to the Earth. However, the attitude angles of a satellite can be perturbed because of various natural disturbance sources, such as the Earth's gravity gradient, solar radiation pressure, and the Earth's magnetic field. Modeling the attitude dynamics and developing a controller to stabilize the attitude motion are quite important steps in the design of satellites. Although several actuators exist to control the attitude motion, a novel type considered in the thesis, shows promise of producing a high torque to mass ratio. This potential justifies the in-depth study reported. The novel actuator in question consists of a ring containing fluid, whose flow is regulated by a pump. The control torque is produced due to the variation of the angular velocity of the fluid. In this thesis, first, a redundant actuator system composed of four fluid rings in a pyramidal configuration is studied. The dynamical model of the system is developed for a satellite travelling either in a circular or an elliptical orbit. The dynamical analysis of this system leads to an underdetermined system of nonlinear differential equations, whose solution without considering the control input (the torque produced by the pump pressure) shows that the fluid rings can damp out the attitude disturbances of a satellite in a circular orbit and the roll-yaw disturbances in an elliptical orbit. However, this passive damping effect is fairly slow; an active controller is hence designed in the next step. The effect of the failure of one fluid ring on the performance of the attitude control subsystem (ACS) of a satellite is also studied. It is observed that even in the case of failure of one fluid ring, the satellite can be stabilized by slight modification of the active controller. Later, a sliding mode controller is designed to cope with the uncertainties existing in the fluid model and in other parameters of the system. Although the results achieved are quite satisfactory, the chattering that exists in the steady response of the system is not desirable; hence a switching controller consisting of a sliding mode and a PID control law is designed to eliminate this chattering effect. Next, the theoretical results obtained are validated by conducting several experiments. Although the experimental results confirm the theory developed in this thesis, the large torque-to-mass ratio expected is revealed to be only possible at the cost of a quite high input voltage to the pumps regulating the flow. Therefore, two novel applications of fluid rings are proposed: as an actuator for spin stabilized satellites, or as an auxiliary actuator in satellites with magnetic torquers.Using fluid rings in spin stabilized satellites is proposed in the thesis, as an alternative to the commonly used micro-thrusters. Here, two fluid rings are mounted on the satellite while their axes of symmetry are aligned with the roll and yaw axes. To examine the feasibility and performance, a dynamical model of this spinning satellite with two fluid rings is developed. A controller is then designed to stabilize the attitude motion of this satellite.The second novel actuator system developed here consists in using fluid rings as complementary actuators in satellites with two magnetic torquers. The dynamical model is formulated, and a controller is designed to investigate the performance of this system. The simulation of the system without the fluid ring shows that the satellite attitude can be stabilized by using only two magnetic torquers, however, slowly. Upon adding the active fluid ring actuator to the system, the stabilization time is reduced by a factor of 10. The failure of the fluid ring and each magnetic torquer is also studied." --
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 1572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fault Tolerant Attitude Estimation for Small Satellites written by Chingiz Hajiyev and published by CRC Press. This book was released on 2020-12-23 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: Small satellites use commercial off-the-shelf sensors and actuators for attitude determination and control (ADC) to reduce the cost. These sensors and actuators are usually not as robust as the available, more expensive, space-proven equipment. As a result, the ADC system of small satellites is more vulnerable to any fault compared to a system for larger competitors. This book aims to present useful solutions for fault tolerance in ADC systems of small satellites. The contents of the book can be divided into two categories: fault tolerant attitude filtering algorithms for small satellites and sensor calibration methods to compensate the sensor errors. MATLAB® will be used to demonstrate simulations. Presents fault tolerant attitude estimation algorithms for small satellites with an emphasis on algorithms’ practicability and applicability Incorporates fundamental knowledge about the attitude determination methods at large Discusses comprehensive information about attitude sensors for small satellites Reviews calibration algorithms for small satellite magnetometers with simulated examples Supports theory with MATLAB simulation results which can be easily understood by individuals without a comprehensive background in this field Covers up-to-date discussions for small satellite attitude systems design Dr. Chingiz Hajiyev is a professor at the Faculty of Aeronautics and Astronautics, Istanbul Technical University (Istanbul, Turkey). Dr. Halil Ersin Soken is an assistant professor at the Aerospace Engineering Department, Middle East Technical University (Ankara, Turkey).
Download or read book Attitude Control Subsystem for the Advanced Communications Technology Satellite written by Alan W. Hewston and published by . This book was released on 1996 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Satellite Attitude Control Using Magnetic Torquers a Periodic Time Varying Control Problem written by and published by . This book was released on 2000 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: Satellite attitude controllers have been designed for a rigid spacecraft whose only actuators are magnetic torque rods. This effort's goals have been to develop a new class of lightweight, moderate accuracy attitude controllers and to evaluate and further develop general methods for the control of time varying systems. Three different classes of controllers have been developed and simulation tested. one based on linear quadratic regulator techniques, one based on sliding mode like concepts, and one based on new H infinity techniques for time varying systems. These H infinity controllers achieve the best performance. In addition to the controller design studies. the issue of attenuation of constant 3 axis disturbances has been addressed. Disturbance attenuation is difficult for this system because it can apply torques only about the 2 axes that are perpendicular to the Earth's magnetic field. It is a challenge to determine how best to counteract a low frequency 3 axis disturbance torque, on average, via judicious use of the fact that the Earth's magnetic field direction varies in time as the spacecraft moves along its orbit. Pointing accuracies on the order of 1 deg or better have been demonstrated in the presence of typical levels of disturbance torque.
Download or read book Spacecraft Attitude Determination and Control written by J.R. Wertz and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 877 pages. Available in PDF, EPUB and Kindle. Book excerpt: Roger D. Werking Head, Attitude Determination and Control Section National Aeronautics and Space Administration/ Goddard Space Flight Center Extensiye work has been done for many years in the areas of attitude determination, attitude prediction, and attitude control. During this time, it has been difficult to obtain reference material that provided a comprehensive overview of attitude support activities. This lack of reference material has made it difficult for those not intimately involved in attitude functions to become acquainted with the ideas and activities which are essential to understanding the various aspects of spacecraft attitude support. As a result, I felt the need for a document which could be used by a variety of persons to obtain an understanding of the work which has been done in support of spacecraft attitude objectives. It is believed that this book, prepared by the Computer Sciences Corporation under the able direction of Dr. James Wertz, provides this type of reference. This book can serve as a reference for individuals involved in mission planning, attitude determination, and attitude dynamics; an introductory textbook for stu dents and professionals starting in this field; an information source for experimen ters or others involved in spacecraft-related work who need information on spacecraft orientation and how it is determined, but who have neither the time nor the resources to pursue the varied literature on this subject; and a tool for encouraging those who could expand this discipline to do so, because much remains to be done to satisfy future needs.
Download or read book Satellite Attitude Control for Steady State Disturbance Using Only Magnetic Torquers written by Maria Korkor Hagan and published by . This book was released on 2000 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Satellite Attitude Control Utilizing the Earth s Magnetic Field written by John S. White (writer on artificial satellites.) and published by . This book was released on 1961 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: The torque developed by the interaction of current-carrying coils with the earth's magnetic field can be used as a means of attitude control. The degree to which the attitude of a vehicle can be maintained utilizing this torque depends on the fluctuations of the magnetic field at the satellite as the satellite orbits about the earth. Due to the nature of the torque developed only two vehicle axes can be c ntinuously controlled simultaneously. With the principle described, either a two- or three-coil system can be used to control vehicle attitude about two axes. Intermittent control about three axes can be obtained. (Author).
Download or read book Advanced Attitude Control of Satellite written by Bing Xiao and published by Springer. This book was released on 2024-07-16 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the high-accuracy attitude control system design and approaches for satellite with modeling error including system uncertainties, actuator faults, and disturbances. It presents a systematically and almost self-contained description of the many facets of envisaging, designing, implementing, or experimentally exploring modeling error compensation-based attitude control of satellites. The advanced treatment of practical issues in satellite attitude compensation control is one of the major features of the book, which is particularly suited for readers who are interested to learn the latest solutions in attitude control system design of satellites. The book intends to provide a unified platform for understanding and applicability of the modeling error compensation-based attitude control for different purposes in aerospace engineering and some related fields. It can benefit researchers, engineers, and graduate students in the fields of attitude control of satellites and other unmanned systems, aerospace engineering, etc.
Download or read book Nonlinear Fault Diagnosis and Recovery for Satellites Using Parameter Estimation Techniques written by Tao Jiang and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fault Detection and Isolation in Attitude Control Subsystem of Spacecraft Formation Flying Using Extended Kalman Filters written by Sara Ghasemi and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Some Notes on Attitude Control of Earth Satellite Vehicles written by Warren Gillespie and published by . This book was released on 1959 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of a Satellite Attitude Control System Using Integrating Gyros as Torque Sources written by John S. White and published by . This book was released on 1961 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
