Organizational Unit:
Daniel Guggenheim School of Aerospace Engineering
Daniel Guggenheim School of Aerospace Engineering
Permanent Link
Research Organization Registry ID
Description
Previous Names
Parent Organization
Parent Organization
Organizational Unit
Includes Organization(s)
Organizational Unit
Organizational Unit
Organizational Unit
Organizational Unit
Organizational Unit
ArchiveSpace Name Record
Publication Search Results
Now showing
1 - 8 of 8
-
ItemDecentralized allocation of safety-critical applications on parallel computing architecture(Georgia Institute of Technology, 2019-08-26) Sutter, LouisThis work presents a decentralized task allocation algorithm for an abstract parallel computing architecture made of a set of Computational Units connected together, each of them being prone to fail. Such an architecture can represent for example a multi-core processor with each Computational Unit standing for one core. The aim of the algorithm is to find the best mapping between Computational Units and the different applications we want to execute on the architecture, while taking into account faulty Computational Resources and the priority of the applications. The proposed approach consists in formulating the allocation problem as an Integer Linear Program (ILP), that is solved thanks to a state-of-the-art ILP solver. The second main aspect of this work is the decentralization the allocation process, in the sense that no central element decides alone of the allocation for the rest of the network. Redundant copies of the allocation algorithm are executed on the architecture itself, meaning that the copies must reallocate themselves. Then, the proposed allocation process is implemented on an experimental setup reproducing the multi-core architecture that inspired this work. Each core is represented by a Raspberry Pi single board computer. The model is used to demonstrate the capabilities of the proposed allocation process to maintain operation of a physical system in a decentralized way, while individual components fail.
-
ItemIntroducing the foundations of a general framework for closed-loop control in additive manufacturing via in situ measurements and semantic annotations(Georgia Institute of Technology, 2018-04-27) Garanger, KevinDuring the last decade, additive manufacturing (AM) has become increasingly popular for rapid prototyping, but has remained relatively marginal beyond the scope of prototyping when it comes to applications with tight tolerance specifications, such as in aerospace. Despite a strong desire to supplant many aerospace structures with printed builds, additive manufacturing has largely remained limited to prototyping, tooling, fixtures, and non-critical components. There are numerous fundamental challenges inherent to additive processing to be addressed before this promise is realized. One ubiquitous challenge across all AM motifs is to develop processing-property relationships through precise, in situ monitoring coupled with formal methods and feedback control. The goal of this thesis is to justify the relevance of closed-loop control in AM, and to pave the way for the creation of a general framework to formulate AM processes as control problems where feedback can be widely adopted. Two experiments of closed-loop control in additive manufacturing for the printing of specific parts are made. These experiments are a proof of concept that feedback control is feasible in AM even without precise physics models of the processes. From this point, a idea for the generalization of closed-loop control in AM is presented via the concept of semantics for AM files and the idea of adapting the local parameters of a printed object through topology optimization.
-
ItemEvaluation of new enroute performance measures for air navigation service providers(Georgia Institute of Technology, 2017-07-27) Piquet, Helene SophieIn a context of steady growth of air traffic world wide, Air Navigation Service Providers must meet increasing demand and report on the quality of their performance. This research presents the design and evaluation of novel performance metrics: the relevance of ATC set of standard routes, the lateral deviation and difference in length and duration between airlines filed flight plans, actual trajectories and wind optimal routes. The proposed metrics are predicated on the necessity for the metrics to be robust, easy to compute and applicable to several different Air Traffic Management Systems, eg. Europe vs USA.
-
ItemResilient, multi-core and safety-critical computing architectures(Georgia Institute of Technology, 2017-07-27) Guillaumet, TomWith the onset of multi-core chips, the single-core market is closing down. Those chips constitute a new challenge for aerospace and safety-critical industries in general. Little is known about the certification of software running on these systems. There is therefore a strong need for developing embedded multi-core architectures, yet compliant with safety-criticality constraints. In this thesis, a reconfigurable multi-core architecture is described. Its suitability for executing safety-critical embedded applications is discussed. It is argued that its dynamic features allow for graceful degradation of the system, and that interference channels can be mitigated if spatial partitioning is enforced on its Network on Chip (NoC). Furthermore, the problem of the allocation of applications on the architecture is formulated as an Integer Linear Programming optimization problem. An algorithm is developed to reallocate the applications running on the fabric when hardware faults occur. The proposed algorithm enforces spatial partitioning on the Network on Chip throughout the reconfigurations. It supports multiple types of NoC topologies, constraints and hardware faults. Finally, the behavior of the presented algorithm is demonstrated in several configurations and for different scenarios of degradation of the architecture. Its performance in terms of computation time is studied, and the results indicate that its use in a real-time environment is possible.
-
ItemSelf-organized traffic flows: a sequential conflict resolution approach(Georgia Institute of Technology, 2013-06-04) Hand, Troy S.This thesis discusses the effect of sequential conflict resolution maneuvers of a continuous flow of agents through a finite control volume. Video analysis of real world traffic flows that exhibit self-organized capabilities is conducted to extract characteristics of those agents. A tool is created which stabilizes the input video and extracts motion from it using the background subtraction method. I discuss the tool in detail as I created it to be user friendly and easily modifiable for other uses. The aim of the video analysis I conduct is to determine characteristics of agents in self-organized traffic flow. Comparisons are made with agents under sequential conflict resolution schemes and those that exhibit these self-organized capabilities to determine if agents under sequential control can approach the behaviors of those in self-organized environment. Flow geometries are studied and generalized with the goal of determining stability characteristics of arbitrary flow geometries. Stability analysis includes analytical proof of bounds on the conflict resolution maneuvers.
-
ItemPeak-seeking control of propulsion systems(Georgia Institute of Technology, 2012-07-10) Cazenave, TimotheePropulsion systems like Turboprop engines are generally designed to operate at a narrow range of optimum steady state performance conditions. However, these conditions are likely to vary in an unpredictable manner according to factors such as components aging, structural damages or even the operating environment. Over time, inefficiencies could add up and can lead to expensive fuel consumption or faster component aging. This thesis presents a self-optimizing control scheme, referred as Peak-seeking control, applied to propulsion systems similar to Turboprop engines. Using an extended Kalman filter, the Peak-seeking method is able drive the system to an optimal condition based only on measurements. No prior knowledge of the engine dynamics is required which make the Peak-seeking technique easy to implement and also allow for modularity in the engine design. This study is performed on both a turboprop and a DC motor driving a variable pitch propeller and considers several performance functions to optimize.
-
ItemEn-route air traffic optimization under nominal and perturbed conditions, on a 3D data-based network flow model(Georgia Institute of Technology, 2012-04-06) Marzuoli, Aude ClaireAir Traffic Management (ATM) aims at ensuring safe and efficient movement of aircraft in the airspace. The National Airspace System is currently undergoing a comprehensive overhaul known as NextGen. With the predicted growth of air transportation, providing traffic flow managers with the tools to support decision making is essential. These tools should aid in accommodating the air traffic throughput increase, while limiting controller workload and ensuring high safety levels. In the National Airspace System (NAS), the goal of en-route Traffic Flow Management (TFM) is to balance air traffic demand against available airspace capacity, in order to ensure a safe and expeditious flow of aircraft, both under nominal and perturbed conditions. The objective of this thesis is to develop a better understanding of how to analyze, model and simulate air traffic in a given airspace, under both nominal and degraded conditions. First, a new framework for en-route Traffic Flow Management and Airspace Health Monitoring is developed. It is based on a data-driven approach for air traffic flow modeling using historical data. This large-scale 3D flow network of the Cleveland center airspace provides valuable insight on airspace complexity. A linear formulation for optimizing en-route Air Traffic is proposed. It takes into account a controller taskload model based on flow geometry, in order to estimate airspace capacity. The simulations run demonstrate the importance of sector constraints and traffic demand patterns in estimating the throughput of an airspace. To analyze airspace degradation, weather blockage maps based on vertically integrated liquid (VIL) are incorporated in the model, representing weather perturbations on the same data set used to compute the flows. Comparing the weather blockages and the network model of the airspace provides means of quantifying airspace degradation. Simulations under perturbed conditions are then run according to different objectives. The results of the simulations are compared with the data from these specific days, to identify the advantages and drawbacks of the present model.
-
ItemAircraft position estimation using lenticular sheet generated optical patterns(Georgia Institute of Technology, 2008-01-24) Barbieri, Nicholas P.Lenticular sheets can be used with machine vision to determine relative position between two objects. If a lenticular sheet of a given period is mounted above periodically spaced lines sharing the same period, lines will appear on the lenticular sheet which translate along the lenticular sheet in a direction perpendicular to observer motion. This behavior is modeled theoretically and tested experimentally, and found to be linear within a finite range. By arranging two lenticular sheets, configured as described above, in a mutually orthogonal configuration on a flat surface, the lines that appear on the lenticular sheets can be used by a camera to estimate its position relative to the lenticular sheets. Two such devices were constructed to test the principle, and machine vision code was developed to ascertain position using these devices. Machine vision code was found to reliably provide angular position of a camera within $1.4^circ$ through experimental testing. The optical patterns that appear on the lenticular sheet surfaces are monitored using a digital camera. The resulting images are analyzed using visual C++ in conjunction with the OpenCV library and the appropriate camera device drivers. The system is able to estimate height, yaw, and position relative to the optical target in real time and without the need for a prior reference.