Development of the L-1011 four-dimensional flight management system

The development of 4-D guidance and control algorithms for the L-1011 Flight Management System is described. Four-D Flight Management is a concept by which an aircraft's flight is optimized along the 3-D path within the constraints of today's ATC environment, while its arrival time is controlled to fit into the air traffic flow without incurring or causing delays. The methods developed herein were designed to be compatible with the time-based en route metering techniques that were recently developed by the Dallas/Fort Worth and Denver Air Route Traffic Control Centers. The ensuing development of the 4-D guidance algorithms, the necessary control laws and the operational procedures are discussed. Results of computer simulation evaluation of the guidance algorithms and control laws are presented, along with a description of the software development procedures utilized

Advances in Intelligent Vehicle Control

This book is a printed edition of the Special Issue Advances in Intelligent Vehicle Control that was published in the journal Sensors. It presents a collection of eleven papers that covers a range of topics, such as the development of intelligent control algorithms for active safety systems, smart sensors, and intelligent and efficient driving. The contributions presented in these papers can serve as useful tools for researchers who are interested in new vehicle technology and in the improvement of vehicle control systems

Advanced flight control system study

The architecture, requirements, and system elements of an ultrareliable, advanced flight control system are described. The basic criteria are functional reliability of 10 to the minus 10 power/hour of flight and only 6 month scheduled maintenance. A distributed system architecture is described, including a multiplexed communication system, reliable bus controller, the use of skewed sensor arrays, and actuator interfaces. Test bed and flight evaluation program are proposed

Advanced Control of Active Distribution Networks Integrating Dispersed Energy Storage Systems

Due to the increased penetration of Distributed Generations (DGs) in distribution networks, the system control and operation may become quite different from the case of traditional network. Most DGs can only provide intermittent power to the Active Distribution Networks (ADNs) due to the intermittent nature of the resources. Moreover, ADN utilities usually do not own DGs, and have difficulty in controlling directly DGs output powers. The main problem related to the considerable connection of DGs is usually associated to the node voltage quality and line congestion mitigation. Within the above context, the motivating factors for this thesis are supported by the issues related to optimal operation and control of ADNs integrating stochastic and non-stochastic DGs. One of the most promising near-term solution is offered by using distributed Energy Storage Systems (ESSs) which can perform their full role to guarantee a more flexible network. Indeed, the availability of ESSs allows, in principle, to: (i) actively control the power flows into the grid, (ii) indirectly control the voltage profiles along the network feeders and (iii) locally balance the hour/daily and weekly load variations. In this thesis, ESSs are assumed to be the only controllable devices in ADNs. As a result, DGs can be indirectly controlled by means of ESSs. First, this manuscript presents control-oriented model for ESSs. In this respect, the accurate estimation of ESS behavior is utmost important. A generic charge representative model for any ESSs is proposed. Moreover, an improvement of the most common electric equivalent circuit models for the two selected ESSs with different characteristics (namely supercapacitors and batteries) is provided for the development of specific control schemes. They are based on the modeling of redistribution of charges that characterizes the dynamic behaviors of the two devices during long time charging/discharging and relaxation phases. Second, this manuscript presents advanced control/scheduling algorithm for ADNs. The operation and control of ADNs can be achieved either centrally or in a decentralized way. The amount of information to be centrally treated would considerably grow due to the number of generation equipmentâs inserted into the grid and the stochastic operation nature of some of them. This consideration introduces the idea that some ADN operation problems, such as voltage control or line congestion mitigation, can be solved in a distributed manner which would help to relieve the information processing burden and to enhance the system security while preventing unwanted event from propagating through the grid. Therefore, the decentralized schemes are considered subdividing the network into quasi-autonomous areas. To this end, given a set of ESSs optimally located in a balanced and radial ADN, this thesis proposes a network partitioning strategy for the optimal voltage control of ADNs. Thus, the network is decomposed into several areas; each under the control of one ESS which has maximum influence on its corresponding area. Based on this clustering, decentralized scheduling strategies and real-time decentralized control algorithms for the clustered ADNs are proposed. The proposed zonal control capability focuses on voltage control and line congestion management. In both proposed decentralized scheduling and real-time control algorithms the communication among different areas is defined using the concept of Multi-Agent Systems

Relativity and the metrology of time

PhDThe motivation for this work is two-fold: the application of general relativity to the metrology of time on one hand (part II), and the use of the methods and technology of time metrology for tests of relativity on the other (part I). In Part I detailed theory for the treatment of the metrology of time in a relativistic context is developed. It provides mathematical expressions for application to the syntonisation and synchronisation of clocks and the realisation of the time coordinates of space-time reference systems. The theoretical expressions are developed to accuracies exceeding those of previous publications in order to accommodate any development in clock and time-transfer technology that can be expected in the near f uture. Part III presents two original experiments which test the theory of special relativity using state-of-the-art time metrology. The first experiment uses data from clock comparisons betweeng round clocks and clocks on board the Global Positioning System( GPS) satellites to test the second postulate of special relativity (the universality of the speed of fight). The experiment is sensitive to a possible anisotropy of the one-way speed of flight in any spatial direction, and on a non-laboratory scale (baselines; -> 20000 Ian) and provides the most stringent limits for the anisotropy published up to date. The second is a proposal for a test of special relativity using a spacecraft that carries an onboard atomic clock and uses a two way time transfer system. The potential accuracy of such a test is evaluated for the ESA/RSA ExTRAS (Experiment on Timing Ranging and Atmospheric Sounding)experiment which was planned for launch in 1997 but is now "on hold".Perren Fun

Laser absorption spectroscopic tomography with a customised spatial resolution for combustion diagnosis

Combustion is a widely used energy conversion technology. However, post-combustion gas emissions have adverse effects on climate change. To address the urgent need for carbon neutrality, efforts are being made to develop cleaner fuels and improve combustion efficiency. Accurate in situ measurements of temperature and species concentration are crucial for analysing and diagnosing the combustion process. In industrial applications, probed-based measurement methods are commonly used to detect temperature and species concentration in the combustion, favoured by their simplicity. However, the probe-based techniques are limited in their spatial resolution, as only point-wise measurements can be provided by them. Additionally, their principle often restricts their temporal resolution, which limits their ability to capture the dynamics of the combustion process. To overcome these limitations, researchers are actively working on developing rapid and multi-dimensional in situ techniques for temperature and species concentration monitoring. Laser Absorption Spectroscopy (LAS) has gained significant attention for its non-intrusive nature and fast response in combustion diagnostics. LAS techniques use an emitter-receiver configuration to measure the line-of-sight light intensity absorbed by species in the gaseous medium. By collecting multiple line-of-sight measurements from different angles, LAS enables tomographic measurement of the combustion process. However, implementations of LAS tomography face challenges due to the physical dimensions of the emitter and receiver and the optical access to industrial combustors. These limitations lead to incomplete measurements, which are key factors of ill-posed problems and artefacts in the reconstructed images. The artefacts lead to inaccuracy and unreliability of the diagnostic results. Increasing physical sampling density is one of the most straightforward ways to alleviate the ill-posed problem caused by inadequate line-of-sight measurements. Improvements in sensors have been demonstrated in previous research, such as optimising laser beam arrangement and reducing the spacing of neighbouring laser beams. In this work, a novel design of a miniature and modular sensor is firstly introduced. It reduces the beam spacing between adjacent laser beams, allowing for a more precise and detailed reconstruction of temperature and species concentration distributions. Meanwhile, modular design allows for customisation and adaptation to various measurement requirements. This flexibility in deployment reduces the cost of the LAS technique. The application of small beam spacing in characterising the non-uniformity of the combustion process has also been demonstrated in this thesis. A multi-channel LAS sensor is developed and applied to exhaust measurements of a commercial auxiliary power unit. The results show that the small beam spacing allows a detailed understanding of the exhaust plume at the mixing zone between the exhaust gas and surrounding air. This spatial information can be used to improve the accuracy of temperature and species concentration measurements. On the other hand, prior knowledge, such as smoothness and sparsity of the measurement target and beam arrangement of the LAS tomographic sensor is used to provide extra physical information to the ill-posed inverse problem. To incorporate the beam arrangement information into the reconstruction process, a new meshing scheme is proposed in this thesis. The scheme dynamically allocates smaller meshes in the beam-dense regions and coarser meshes in the beam-loose regions. This adaptive meshing scheme ensures a finer resolution in detailing the combustion zone where the beams are closely spaced while maintaining the integrity of the physical model by using less resolved reconstruction in the bypass flows or regions where the beams are further apart. As a result, the proposed meshing scheme improves the reconstruction accuracy of the combustion zone. Overall, this PhD project designed and developed LAS tomographic sensors and methods that enable accurate and fast measurement of gas temperature and species concentration in combustion processes with a customised spatial resolution. The main contributions of this thesis include the design and prototyping of a miniature and modular optical sensor for flexible LAS tomography; the development of a multi-channel LAS sensor for simultaneously monitoring exhaust gas temperature and water vapour concentration in gas turbine engines; and the development of a size-adaptive hybrid meshing scheme to improve the reconstruction of target flow fields

Journal of Telecommunications and Information Technology, 2004, nr 2

kwartalni

Energy-efficient wireless communication

In this chapter we present an energy-efficient highly adaptive network interface architecture and a novel data link layer protocol for wireless networks that provides Quality of Service (QoS) support for diverse traffic types. Due to the dynamic nature of wireless networks, adaptations in bandwidth scheduling and error control are necessary to achieve energy efficiency and an acceptable quality of service. In our approach we apply adaptability through all layers of the protocol stack, and provide feedback to the applications. In this way the applications can adapt the data streams, and the network protocols can adapt the communication parameters