Navigation, Guidance, Control and Dynamics Commons^™

Identifiability Of Additive, Time-Varying Actuator And Sensor Faults By State Augmentation, Jason M. Upchurch

Electrical & Computer Engineering Theses & Dissertations

Faults in dynamical systems can have serious safety and reliability implications. For example, actuator and sensor faults have been factors in past incidents and mishaps in many aerospace systems. A large body of research is devoted to developing methods to detect and identify actuator and sensor faults in such systems.

One fault detection and identification menthol employs state augmentation, whereby a set of time-varying faults of interest are modeled as outputs of exogenous linear, time-invariant systems and augmented to the state of the nominal system model. The resulting model represents the system dynamics due to a particular actuator-sensor fault configuration. …

Unmanned Aerial Vehicles Collision Avoidance From Moving Obstacles, Atila Ozdemir

Electrical & Computer Engineering Theses & Dissertations

The usage of the unmanned aerial vehicles (UAV) is becoming more diverse day by day in both military and civil applications. Specifically in military applications, they are becoming a "must-have" component in every arsenal. Low cost, and especially the importance of human life, makes these vehicles desired in any military situation. But in order to take advantage of the UAVs, these vehicles should be able to navigate safely and not collide with other air vehicles, especially ones that are manned and carry personnel. As a result, the importance of a collision avoidance system of the UA V arises and begins …

Investigation And Comparison Of Proportional Navigation Guidance And Beam Rider Guidance, Ertac Olgun

Electrical & Computer Engineering Theses & Dissertations

Air defense has an increasing importance in today's wars. To gain the advantage in air combat, pursuit interceptor aircraft, which use Air-to-Air Missiles (AAMs), have become more and more significant. However, these are not sufficient alone. The importance of Surface-to-Air Missiles (SAMs) also can not be ignored in air defense.

SAMs can use different tactical navigation guidance methods. Of these, two of the more important guidance methods are Proportional Navigation Guidance and Beam Rider Guidance, which are investigated in this thesis. To understand the idea better, a brief description and discussion of missiles are provided. Parts of the guided missiles …

Fault-Injection Experiment For The Statistical Characterization Of Faults In Avionics Communication System, Amy M. Yates

Electrical & Computer Engineering Theses & Dissertations

Since flight control systems perform safety-critical functions, it is important to understand the possible effects on the closed-loop dynamical system's performance caused by these faults. The purpose of this project is to design the software and hardware needed to add fault-injection and monitoring capabilities to ROBUS-2, a flight communication system. ROBUS-2 is the current version of the fault-tolerant computer communication system used by the Scalable Processor-Independent Design for Enhanced Reliability (SPIDER), a general-purpose fault-tolerant integrated modular architecture (IMA) developed at the NASA Langley Research Center. The major components of SPIDER include processing elements (PEs) to perform calculations, bus interface units …

Performance Analysis Of Recoverable Flight Control Systems Subject To Neutron-Induced Upsets Using Hybrid Dynamical Models, Hong Zhang

Electrical & Computer Engineering Theses & Dissertations

It has been observed that atmospheric neutrons can produce single-event upsets in digital flight control hardware. Potentially, they can reduce system performance and introduce a safety hazard. One experimental system-level approach investigated to help mitigate the effects of these upsets is NASA Langley's Recoverable Computer System. It employs rollback error recovery using dual-lock-step processors together with new fault tolerant architectures and communication subsystems.

In this dissertation, a class of stochastic hybrid dynamical models, which consists of a jump-linear system and a stochastic finite-state automaton, is used to describe the performance of a Boeing 737 aircraft system in closed-loop with a …

Analysis Of Error Recovery Effects On Digital Flight Control Systems, Arturo Tejada Ruiz

Electrical & Computer Engineering Theses & Dissertations

Life-critical, real-time applications like flight-by-wire aircraft, rely on closed-loop digital control systems and fault-tolerant computer systems to reliably achieve the desired operation. The computer systems, however, may be affected by random hardware/software faults induced mainly by environmental conditions such as high intensity radiated fields (HIRF) and lightning. These harsh electromagnetic environments are known to induce common­ mode faults (CMF) in aircraft electronic systems, which disrupt fault-tolerant provisions and possibly affect the operation of the digital control system. Current flight-by-wire aircraft have computer systems that can neither detect CMF nor recover from them. New systems are under investigation that can recover …