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Networked control systems (NCSs) are feedback control systems with the feedback control loops closed via network. The origin of the term NCSs is from industrial systems where the plant and controller are often connected through networks. The applications of NCSs cover a wide range of industries, for example, manufactory automation, domestic robots, aircraft, automobiles and tele-operations. The research activities in NCSs are focused on the following three areas: control of networks, control over networks and multi-agent systems. Control of networks is mainly concerned with the problem of how to efficiently utilize the network resource by controlling and routing the network data flows. Control over networks is mainly concerned with the design of feedback control strategies of control systems in which signals are transmitted through unreliable communication links. Multi-agent systems deal with two problems: how the topology of the network connections between each component influences global control goals and how to design local control law describing the behavior of each individual to achieve the global control goal of the whole systems. The objective in this thesis is to deal with control over networks and multi-agent systems. The most challenging problem in the control over networks field is that the unreliable communication channels can degrade system performance greatly. The main unreliable properties of networks are delays and packet loss. In order to deal with this problem, a Lyapunov-based method has been used to design the sampled-data stabilization control strategy for a networked single system by choosing proper delay and packet loss dependent Lyapunov functional candidates. Linear matrix inequality techniques have been used to find the sufficient and necessary conditions for the controller design. Furthermore, the consensus formation control problem of multiple robotic vehicle systems has been investigated. The consensus-based design scheme has been applied to the formation control of multiple wheeled mobile-robot group with a virtual leader. A novel delay-dependent Lyapunov functional candidate has been constructed to investigate the convergence of the system states. The proposed control strategy is experimentally implemented for multiple wheeled mobile robots under neighbor-to-neighbor information exchange with group communication delays involved. In conclusion, through the simulation results and experimental validations, the proposed new Lyapunov-based control methods can effectively deal with the networked control systems discussed in this thesis.

Idag blir användningen av drönare allt mer vanlig för dokumentation av markytor. Det är ett billigare alternativ för att dokumentera små och otillgängliga områden. Genom tekniken går det bland annat att framställa olika digitala modeller som representerar jordens yta. En sådan modell kan vara en terrängmodell (DTM) som är en modell av markytan exklusive vegetation, hus eller annat som befinner sig på marken. Modeller kan framställas genom flygdata såsom laserskannad (LiDAR-data) eller flygfotograferade data (flygbilder). För att framställa en digital modell från rådata används olika programvaror. Den här studien utvärderar två olika programvarors förmåga att framställa digitala terrängmodeller från flygbilder. Främst undersöks levererade osäkerheter och användarvänligheten i programmen. Referensdata som användes i denna studie tillhandahölls av Norconsult och samlades in vid ett projekt över Hammarbyhöjdsskogen i Stockholm, hösten 2018. Den data som erhölls från projektet till denna studie var flygbilder samt terrestra detaljmätningar. Programmen som studien utvärderar är UAS Master som både använder datorseende och fotogrammetriska metoder och SURE Aerial som använder datorseende. Genom studien visade det sig att fler än de ursprungliga programvarorna behövdes för att framställa de digitala terrängmodellerna och vidare jämföra dessa. En orsak var att UAS Master saknade förmågor att redigera och visa punktmoln i 3D-vy och vidare skapa en DTM. Detta resulterade i att använda Trimble Business Center för slutarbetet. En annan orsak var att SURE Aerial visade sig vara avsett för framställning av digitala ytmodeller (representation av den faktiska, synliga ytan). För att framställa en DTM av punktmolnet användes både Cloud Compare och Agisoft Photoscan (numera Metashape). Geo användes sedan för att ta ut höjdavvikelserna från modellen. Två slutsatser som kunde dras utifrån denna studie var: 1) trots de olika tillvägagångssätten erhölls snarlika resultat för marktypernas lägesosäkerheter för respektive programvara (asfalt: 0,039 m; grus: ca 0,040 m; gräs: ca 0,048 m), varpå alla blev godkända enligt HMK – Flygfotografering 2017; 2) SURE Aerial är ett enklare och snabbbare program men med UAS Master har man som användare bättre förståelse över processerna och erhåller bättre dokumentation. / Drones have become a more and more frequent tool to document the surface of the ground, especially in smaller areas that otherwise are too expensive to observe by other means. This technology makes it possible to create digital terrain models (DTM) that represents the surface of the ground excluding vegetation, houses or other objects on the ground. These models can be created by laser scanned data (LiDAR-data) or aerial photogrammetry (aerial photos).  In order to create a digital model from raw data are various software needed. This study aims to test two software’s ability to create digital terrain models from UAS photos. The software were evaluated by the uncertainties of the models, as well as the user-friendliness of each software. All data used in this study was collected by Norconsult for another project in 2018 and consist of UAS photos and data from terrestrial measurements.  The softwares used in this study for comparison are UAS Master (using both computer vision and photogrammetric methods) and SURE Aerial (using computer vision). It turned out that additional use of software were needed to create DTMs that were comparable. UAS Master could not show or edit point clouds in 3D, because of this the software Trimble Business Centre had to be used. This program was also used to obtain height deviations. SURE Aerial on the other hand turned out to only be able to create digital surface models (models of the visible ground). The software Cloud Compare and Agisoft Photoscan (nowadays Metashape) were therefore used to create the DTM from the point cloud. The height deviations from the ladder DTM were obtained from the software Geo. Two conclusions could be drawn from this study: 1) the uncertainties of the different surface types were similar in the software despite the different ways to create the DTMs (asphalt: 0.039 m; gravel: 0.040 m; grass: 0.048 m). All of which meet the requirements according to HMK – Flygfotografering 2017; 2) SURE Aerial is a lot easier and quicker to work with but UAS Master give the user a lot more feedback in the way of documentation throughout the different processes.

This dissertation is focused on the quantitative metrics of performance, cost, and reliability for future launch vehicles. Methods are developed that hold performance constant for a required mission and payload so that cost and reliability can be traded. Reliability strategies such as reducing the number of engines, increasing the thrust-to-weight ratio, and adding redundant subsystems all increase launch vehicle reliability. However, there are few references that illustrate the cost of increasing launch vehicle reliability in a disciplined, integrated approach. For launch vehicle design, integrated performance, cost, and reliability disciplines are required to show the sensitivity of cost to different reliability strategies. A methodology is presented that demonstrates how to create the necessary launch vehicle reliability models and integrate them with the performance and cost disciplines. An integrated environment is developed for conceptual design that can rapidly assess thousands of launch vehicle configurations. The design process begins with a feasible launch vehicle configuration and its mission objectives. The performance disciplines, such as trajectory analysis, propulsion, and mass estimation are modeled to include the effects of using different reliability strategies. Reliability models are created based upon the launch vehicle configuration. Engine reliability receives additional attention because engines are historically one of the leading causes of launch vehicle failure. Additionally, the reliability of the propulsion subsystem changes dynamically when a launch vehicle design includes engine out capability. Cost estimating techniques which use parametric models are employed to capture the dependencies on system cost of increasing launch vehicle reliability. Uncertainty analysis is included within the cost and reliability disciplines because of the limited historical database for launch vehicles. Optimization is applied within the integrated design environment to find the best launch vehicle configuration based upon a particular weighting of cost and reliability. The results show that both the Saturn V and future launch vehicles could be optimized to be significantly cheaper, be more reliable, or have a compromise solution by illustrating how cost and reliability are coupled with vehicle configuration changes.

There is a large number of design options to consider when designing aircraft vehicle systems for fighter aircraft, and there is a lack of tool support that provides an overview of these available design options. Various design options will bring consequences in terms of weight, performance, cost, etc. which is desired to be known in an early conceptual phase. Conventional methods, such as morphological matrix and design structure matrix, lack the ability to generate an overview and map complex systems. By studying model-based tools in form of ontologies and feature models in Protégé and FeatureIDE respectively, these tools are considered to provide a higher level of detail regarding the available design options compared to the conventional methods, such as the morphological matrix and the design structure matrix. Ontologies and feature-models are therefore considered to increase the effectiveness in the conceptual design phase of aircraft vehicle systems. By combining ontologies and feature models, more thoughtful design decisions can be performed. An increased knowledge of the available design options can lead to an improved development of aircraft vehicle systems, and new solutions can be evaluated. By performing more detailed trade studies for an unmanned aerial vehicle, for different system solutions, various parameters such as engine power outtake, system weight, etc. can be analysed and provide an indication whether a concept should be evaluated further. It is however necessary to consider how different parameters affect the overall system, and fuel penalty may be implemented as an equivalent parameter. Performing power flow calculations do however not consider solution-specific limitations, which have to be implemented to be able to determine if an aircraft vehicle system concept should be considered advantageous or not.

Approved for public release, distribution is unlimited / The Marine Corps is fielding the MTVR Truck as a replacement for its aging fleet of five-ton cargo trucks. The MTVR is an Acquisition Category II program that was a multi-service Army-Marine Corps program. The purpose of this thesis is to examine the effectiveness of having an Army Product Office execute a Marine Corps Program. The study analyzes the effectiveness of the timing of the program's transition from the Army to the Marine Corps. A detailed literature search, as well as information gathered from attending various IPRs and conducting interviews with program officials and contractors, provided the basis for the in-depth background study presented. Analysis of the data gathered led to a justification for multi-service managed programs, as well as to recommendations on the timing of the MTVR program transition. / Civilian, United States Army

Commercial Aircraft Corporation of China, Ltd (COMAC)and Chinese Scholarship Council. / The aim of this thesis is to develop a real time PIO detection and mitigation system that consists of a detector based on short time Fourier transform(STFT) and autoregressive model(ARX) with exogenous inputs, together with an adaptive controller based mitigation system. The system not only detects the traditional PIO characteristics but also focuses on the trend of pilot behaviour by calculating the rate of change in the open loop crossover frequency. In the detection system, a sliding windowed STFT method was applied to identify the frequency and phase characteristics of the system via processing the signal of pilot input and aircraft state. An ARX model was also applied to get the rate of change of the crossover frequency. After detection, a PIO cue was shown on the primary flight display. A scheduled gain controller was coupled to provide PIO mitigation by varying stick input gain. Compensatory and tracking tests for the evaluation of this system were performed using a quasi-linear Boeing-747 aircraft model including nonlinear command gearing and actuator rate-limiting. Bandwidth and Gibson criteria were used to design PIO prone control laws for system evaluation experiments. Results from PIO tests conducted on desktop PCs were presented. These were analyzed and compared with those obtained from implementing the Real-time Oscillation Verifier module available in literature.