; Oh+'0HP
$TU Delft Repository search results0TU Delft Repository search results (max. 1000)TU Delft LibraryTU Delft Library@gU@gU՜.+,0HPX`hp
x
WorksheetFeuilles de calcul
B=%r8X"1Calibri1Calibri1Calibri1
Calibri 83ffff̙̙3f3fff3f3f33333f33333.
zTU Delft Repositoryg tuuidrepository linktitleauthorcontributorpublication yearabstract
subject topiclanguagepublication type publisherisbnissnpatent
patent statusbibliographic noteaccess restrictionembargo datefaculty
departmentresearch group programmeprojectcoordinates)uuid:af94d53518534a6c8b3f77c98a52346aDhttp://resolver.tudelft.nl/uuid:af94d53518534a6c8b3f77c98a52346aVOpen Aircraft Performance Modeling: Based on an Analysis of Aircraft Surveillance Data'Sun, J. (TU Delft Control & Simulation)tHoekstra, J.M. (promotor); Ellerbroek, J. (copromotor); Delft University of Technology (degree granting institution)
A large number of stakeholders exist in the modern air traffic management ecosystem. Air transportation studies benefit from collaboration and the sharing of knowledge and findings between these different players. However, not all parties have equal access to information. Due to the lack of opensource tools and models, it is not always possible to undertake comparative studies and to repeat experiments. The barriers to accessing proprietary tools and models create major limitations in the field of air traffic management research. This dissertation investigates the methods necessary to construct an aircraft performance model based on open data, which can be used freely and redistributed without restrictions. The primary data source presented in this dissertation is aircraft surveillance data that can be intercepted openly with little to no restriction in most regions of the world. The eleven chapters in this dissertation follow the sequence of open data, open models, and performance estimations. This order corresponds to the three main parts of the dissertation. In the first part of the dissertation, open surveillance data is explored. Methods are developed to decode and process this data. Extraction of information is also made possible thanks to machine learning algorithms. The second part of the dissertation examines the main components of the open aircraft performance model. Models related to kinematics, thrust, drag polar, fuel flow, and weather are investigated. The third part of the dissertation looks into the possibility of using surveillance data to estimate aircraft performance parameters, for example, aircraft turn performance, aircraft mass, and thrust settings, for individual flights. With the goal of making future air traffic management studies more transparent, comparable, and reproducible, the models and tools proposed in this dissertation are fully open. The final aircraft performance model, OpenAP, proposed in this dissertation has proven to be an efficient open alternative to current closedsource models.Aircraft Performance; Air Traffic Management; ADSB; Drag Polar; Dynamic Model; Engine Fuel Flow; Kinematic Model; MeteoParticle; ModeS; Open Data; State Estimation; Thrustendoctoral thesis9789463840309
20190614)uuid:edf396c55c3a4b5c9fc4b8bb5ff6eeeeDhttp://resolver.tudelft.nl/uuid:edf396c55c3a4b5c9fc4b8bb5ff6eeeeQQualitative and Quantitative Imaging in Electromagnetic Inverse Scattering Theory7Sun, S. (TU Delft Microwave Sensing, Signals & Systems)lYarovyi, O. (promotor); Kooij, B.J. (promotor); Delft University of Technology (degree granting institution)g
The inverse scattering problem is inherently nonlinear and improperly posed. Relevant study, such as the existence and uniqueness of the solution, the completeness of the far field pattern, etc., involves an abstruse mathematical theory. In our daily life, the inversion techniques play a significant role in areas such as radar, sonar, geophysical exploration, medical imaging and nondestructive testing. This thesis is focused on the qualitative and quantitative reconstruction of shape and medium parameters of scattering objects in electromagnetic inverse scattering theory. The major contributions of this thesis are 1) the proposal of a novel crosscorrelated error termand 2) the proposal of the sumofnormregularized reconstruction algorithm. The significance of the former lies in the fact that the proposed error< term fills up a gap hidden in the classical state error data error cost functional. In the optimization approaches, the data error term tends to recover the unknown properties of the objects directly from the measurement data, while the state error term attempts to ensure that the recovered results satisfy Maxwell s equations in the field domain. In other words, the solution must behave well in both the measurement domain and the field domain. However, there is still a gap in between because the minor mismatch in the field domain is not monitored in the measurement domain. The proposed crosscorrelated error is a constraint which tends to get the mismatch in the field domain under control in the measurement domain. Therefore, one can say that this novel error term revolutionizes the formulation of the minimization functional of inversion techniques based on optimization theory. The significance of the latter is that the proposed reconstruction scheme enables us to excavate the joint information hidden in the formulation of multiple inverse source problems, without any significant additional computational effort. Although the sumofnorm regularization is not necessarily the best regularization constraint for some complicated scatterers, it demonstrates at least two points: 1) for an inverse source problem, benefits can be obtained from use of different incident fields; 2) the sumofnorm regularization brings better resolving ability due to the joint processing of the multiple contrast source vectors. The research results in this thesis are also applicable to the acoustic inverse scattering problems. Application of the qualitative and quantitative reconstruction approaches developed in this thesis to the experimental data in different areas of wavefield inversion would be very interesting as future work.9789402809121Shilong Sun was born in Zhangqiu, Shandong, China, in 1988. He received the B.S. and M.S. degrees in information and communication engineering from the National University of Defense Technology, Changsha, China, in 2011 and 2013, respectively. He joined the Microwave Sensing, Signals and Systems group, Delft University of Technology (The Netherlands) in 2013, where he started working towards his Ph.D. degree in the field of electromagnetic inverse scattering problems.)uuid:37d758b5bf354a3483c9235008eaf116Dhttp://resolver.tudelft.nl/uuid:37d758b5bf354a3483c9235008eaf116aMetalOrganicFramework mediated supportedcobalt catalysts in multiphase hydrogenation reactions.Sun, X. (TU Delft ChemE/Catalysis Engineering)sKapteijn, F. (promotor); Gascon Sabate, J. (promotor); Delft University of Technology (degree granting institution)The production of most industrially important chemicals involves catalysis. Depending on the difference in phases between the catalysts and reactants, one distinguishes homogenous catalysis and heterogeneous catalysis, with the latter being more attractive in real applications, due to the easy separation of products from catalysts and reusing the latter. In spite of the research and development of heterogeneous catalysts for decades, the exploration for catalysts system with outstanding activity, stability and selectivity remains a challenging task. In general, most of the chemical reactions occur on the surface atoms of supported metal (oxide) nanoparticles. Therefore, to address this challenge, current studies generally focus on understanding the relation between the catalytic performance and catalyst properties by controlling the particle size and distribution, and even<br/>the shape of supported nanoparticles, and the interaction between nanoparticles and support. In order to further contribute to this objective, in this thesis we applied metalorganicframeworks (MOFs) as a sacrificial precursor to produce catalysts for catalytic hydrogenation reactions, important routes for the production of a variety of fine and bulk chemicals in industry.9789402808087)uuid:7fe64dde7fb543928160da6f7916dc6bDhttp://resolver.tudelft.nl/uuid:7fe64dde7fb543928160da6f7916dc6bkEstim< ating geocenter motion and changes in the Earth s dynamic oblateness from GRACE and geophysical modelsSun, Y. (TU Delft Atmospheric Remote Sensing)mKlees, R. (promotor); Riva, R.E.M. (copromotor); Delft University of Technology (degree granting institution)]Geocenter motion and changes in the Earth s dynamic oblateness (J2) are of great importance in many applications. Among others, they are critical indicators of largescale mass redistributions, which is invaluable to understand ongoing global climate change. The revolutionary Gravity Recovery and Climate Experiment (GRACE) satellite mission enables a constant monitoring of redistributing masses within the Earth s system. However, it still cannot provide reliable time variations in degree1 coefficients and degree2 zonal coefficients, which are directly related to geocenter motion and J2 variations.Geocenter motion; J2; Temporal gravity field variations; Mass transport; Glacial isostatic adjustment; GRACE; Satellite Laser Ranging9789463610162)uuid:e83b184cc972402aa0c6418222cf11adDhttp://resolver.tudelft.nl/uuid:e83b184cc972402aa0c6418222cf11ad0The Lifetime Prediction of LED Drivers and LampsBSun, B. (TU Delft Electronic Components, Technology and Materials)TZhang, G.Q. (promotor); Delft University of Technology (degree granting institution)tLightEmitting Diodes (LEDs) have become a very promising alternative lighting source with the main advantages of a longer lifetime and a higher efficiency than traditional ones. However, the LED lamp s lifetime is compromised by its driver s reliability. Although extensive studies have been made on the reliability of LEDs, the research on the lifetime prediction for LED drivers, and the interaction of the reliability between LEDs and driver in an LED system is still lacking. This dissertation investigates the lifetime predictions for LED drivers and LED lamps using physics of failure (PoF) based reliability simulations. Various reliability and statistical methods, such as theMonte Carlo method, the faulttree method, the Markov Chain method, and the Wiener process, are applied and integrated with the electronicthermal simulation in order to investigate various problems.kLED Driver; LED Lamp; Reliability; Solid state lighting; Lifetime prediction; Electronicthermal simulation)uuid:11717f7d51c9471b8f9eee1a70e7f032Dhttp://resolver.tudelft.nl/uuid:11717f7d51c9471b8f9eee1a70e7f032CFlexible CMOS SinglePhoton Avalanche Diode Image Sensor Technology$Sun, P. (TU Delft FTQC/Ishihara Lab)KCharbon, E.E.E. (promotor); Ishihara, R. (promotor); Sarro, P.M. (promotor)rsinglephoton avalanche diode; SOI; flexible substrate; CMOS integration; photon counting and image sensor; 8668019789402803143
20180101)uuid:d5a91375c9954dcfb499c593b80ceac1Dhttp://resolver.tudelft.nl/uuid:d5a91375c9954dcfb499c593b80ceac13Plasticity under rough surface contact and frictionSun, F./Thijsse, B.J. (promotor); Nicola, L. (promotor)4The ultimate objective of this work is to gain a better understanding of the plastic behavior of rough metal surfaces under contact loading. Attention in this thesis focuses on the study of single and multiple asperities with micrometer scale dimensions, a scale at which plasticity is known to be size dependent. The asperities have very simple geometries, either rectangular or sinusoidal and they are pressed into contact with a rigid platen. The analysis is performed using the discrete dislocation (DD) plasticity method, given its accuracy to describe microscale plasticity and its capability of predicting size effects. In DD, plasticity is modeled as the collective motions of discrete dislocations dislocations, which are modeled as line singularities in an otherwise isotropic linear elastic medium. The dislocation Burgers vector is the material length scale that allows to capture plasticity size effects. In Chapter 2, simulations are performed to investigate the flattening of a sinusoidal surface, for different dimensions and shape of the sinusoid. A size dependent response is found for asperities with t< he same amplitudetoperiod (A/w) ratio. The smaller asperities are more difficult to deform plastically due to the limited dislocation density at the same strain. It is observed that the mean contact pressure can reach values up to about 40 times the yield pressure, thus significantly higher than what is predicted by the classical plasticity theory. This is mainly caused by the fact that the area of intimate contact is discontinuous and therefore the distribution of contact pressure is highly non homogeneous. Smaller contact regions are characterized by a very high stress concentration. The simulation results are rather insensitive to the contact conditions used, i.e. frictionless or sticking. When flattening periodic sinusoidal waves, it is not possible to assess a possible size dependence related to the spacing between asperities, since decreasing asperity spacing also reduces asperity size. Therefore in Chapter 3, simulations are performed for the flattening of an array of equally spaced sinusoidal asperities. This allows to investigate the effect of plastic interaction between neighboring asperities on the contact pressure. It is found that the mean contact pressure necessary to flatten closely spaced asperities is larger than that required to flatten widely separated asperities. The socalled asperity density effect is already present in purely elastic materials, and becomes more pronounced when plasticity is described by discrete dislocations. The origin of the asperity density effect is found to be a combination of plastic strain gradients, dislocation limited plasticity and interaction between plastic zones. In Chapter 4, simulations are performed to investigate the effect of flattening on the subsequent shearing behavior of a rectangular asperity protruding from a large single crystal. The shearing is applied after the pillar is flattened to different depths. In large asperities, i.e. a couple of square micrometers, the dislocations generated during flattening promote early plasticity upon shearing, i.e the contact shear stress is reduced, when plastic deformation takes place upon flattening. However, flattening smaller asperities to the same displacement, instead, does not affect subsequent plastic shearing. Despite there are many dislocations in the asperities, they are closely packed on a few active slip planes and therefore have smaller mobility. The simulations are also performed for on multiple asperities to investigate the effect of spacing on their shearing behavior. It is found that closely spaced asperities are easier to plastically shear than isolated asperities. This effect is mainly triggered by the fact that shearing closely spaced asperities in the elastic regime gives rise to a wide region in the subasperity where the shear stress is large and therefore facilitates dislocation nucleation. This effect fades when asperities are very protruding, and plasticity mainly occurs inside of the asperities. In Chapter 5, simulations are performed to investigate the static frictional behavior of a metal asperity on a large single crystal, in contact with a rigid platen. The focus of this chapter is on understanding the relative importance of plasticity and contact sliding in a single asperity at a scale where plasticity is size dependent. Sliding of a contact point is taken to occur when the shear traction exceeds the normal traction at that point times a friction coefficient. Plasticity initiates through the nucleation of dislocations from FrankRead sources in the metal and is modeled as the collective motion of edge dislocation. Results show that at large contact pressures and friction coefficients, plasticity controls the frictional behavior of a single asperity. When selfsimilar asperities of different size are flattened to the same depth while loaded tangentially, there is no trace of a size effect in their frictional behavior. However, when they are submitted to the same contact pressure smaller asperities slide while larger asperities deform plastically.acontact mechanics; rough surface; dislocation dynamics; sur< face topography; size effect; friction.Mechanical, Maritime and Materials Engineering!Materials Science and Engineering)uuid:89455d9afb3842bfb1db03a8a5104bcfDhttp://resolver.tudelft.nl/uuid:89455d9afb3842bfb1db03a8a5104bcfZModel and Sensor Based Nonlinear Adaptive Flight Control with Online System Identification Sun, L.G.+Mulder, M. (promotor); Chu, Q.P. (promotor)jCConsensus exists that many lossofcontrol (LOC) in flight accidents caused by severe aircraft damage or system failure could be prevented if flight performance could be recovered using the valid and remaining control authorities. However, the safe maneuverability of a postfailure aircraft will inevitably be reduced due to the malfunction. Nonconventional control strategies which rely on modern control techniques and computational power are essential to control systems in postfailure flight conditions to extract the most from the reduced, remaining aircraft control authorities and restore the flight performance of an aircraft or achieve a safe landing. One such nonconventional control strategy is called active fault tolerant flight control (FTFC), which is designed to detect changes in an aircraft's dynamics caused by structural, actuator, or sensor failure and accommodate the damage or failure using an adaptive reconfiguration mechanism. The active FTFC technique is able to deal with unanticipated and multiple simultaneous failures. The overall architecture of an active FTFC system ideally should consist of a fault detection and diagnosis (FDD) module, a state reconstruction unit, a reconfigurable control component, a control allocation unit and a flight envelope protection (FEP) unit. Generally speaking, FTFC systems can be classified into two types: modelbased FTFC systems and modelfree FTFC systems, according to whether any of the system's components require an aerodynamic model at their core or not. A modelbased FTFC system contains an aerodynamic model identification (AMI) module, which supplies an accurate aircraft model to an indirect adaptive nonlinear controller in the reconfigurable control block, to a dynamic flight envelope determination algorithm in an FEP unit, or to an FDD unit. An aerodynamic model identification approach using a physical, interpretable modeling structure can detect and even quantify structural failures occurring in the aircraft structure or one of the control surfaces by monitoring changes in stability derivatives and control derivatives. There are many candidate control approaches which can achieve reconfiguration when designing a reconfigurable flight controller. These reconfigurable control methods may rely on many different reconfiguration mechanisms ranging from switching, model following, matching to adaptive compensation. These methods include nonlinear adaptive control which achieves reconfiguration through compensation, and this method is receiving increasing attention in the flight control aerospace research community. Nonlinear adaptive control is divided into direct adaptive control and indirect adaptive control, the difference is that the latter requires an online system model. Indirect adaptive control is also called modelbased or modular adaptive control, which has some advantages over the direct adaptive control and other modelfree control methods. One advantage is that a modular control approach has the potential to yield a more efficient controller which requires less control effort. Such an efficient controller can be achieved by maintaining useful damping terms of an identified system model in the closedloop system. This is attributed to the good properties of many control design techniques such as backstepping such that the dynamics of an original system can be chosen to be canceled or maintained during a controller design process. Modular adaptive control also has an inherited shortcoming, it can only guarantee inputtostate stability, i.e. modular adaptive control cannot guarantee the stability of the overall closedloop system because its stability proof relies on the certainty equivalence prin< ciple. The weakness of the certainty equivalence principle, i.e., convergence problem of the model parameters, can be improved by enhancing model accuracy or reliability, to do this, it becomes critical to develop advanced, powerful aerodynamic model identification approaches capable of capturing changes in flight dynamics either during a high maneuvering flight mission or a postfailure condition. Flight envelope protection is a necessary technique that should be applied by controller designers to prevent LOC incidents, taking into account highly maneuvering flight tasks and/or highly perturbed flight conditions due to the ongoing failure. An FEP component should provide a pilot with a safe flight envelope and pose constraints on the reference commands fed to an internal controller to make the commands achievable. An aerodynamic model that is valid over an entire flight envelope plays a crucial role in fullenvelope modular adaptive control and flight envelope protection. A globally valid model is required for modular adaptive control to enable the designed controller to work properly in a large operating range. Once estimated, the global model in a modelbased adaptive control method can be stored for later reuse when the same flight condition is revisited. Except being needed by a modelbased controller, an accurate aerodynamic model is also required for flight envelope protection. Naturally, the estimated aerodynamic model has to be valid for the current aircraft configuration over the entire flight envelope to enable an evolution algorithm to estimate the boundary of the safe flight envelope for the current flight condition. However, only a limited number of model identification approaches are suited for estimating a globally valid aerodynamic model, and each existing possible candidate has variant shortcomings or limitations which make it hard to apply directly to identify an aircraft model. For example, neural networks usually yield a nontransparent model structure which is hard to interpret using physical knowledge of the system, and they commonly encounter a convergence problem. Most kernel methods fall into the nonparametric type of methods, which by nature need as many kernels as the data points under evaluation. It should be kept in mind that only equationerror type model identification methods were investigated in the work reported here. The assumption was made that a sufficiently accurate estimation of aircraft states was available. An alternate method to the modular adaptive reconfigurable control approach is the acceleration measurementsbased incremental nonlinear control (AMINC) method. An accurate estimation of an aircraft is hard to achieve during a high maneuvering moment or at a transient period when the flight performance is highly perturbed due to aircraft failure. Incremental nonlinear controllers such as incremental nonlinear dynamic inversion (INDI), incremental backstepping (IBKS) and sensorbased backstepping (SBB) are suited for reconfigurable flight control designs in the sense that they do not require complete aircraft model knowledge. The main research question for the research presented here was: How can an advanced faulttolerant flight control system be designed to increase the survivability of an aircraft? This led to two subsidiary questions: (1). How can the candidate function approximation methods, i.e. multivariate simplex Bsplines and kernel methods, be improved in terms of approximation accuracy and computational efficiency, to meet the need of modelbased adaptive control and online flight envelope protection? (2). What are the benefits of using an acceleration measurementsbased control approach, i.e., the sensor based backstepping, as an alternative to a modelbased adaptive control approach, when designing a reconfigurable flight controller to deal with aircraft failures in a generic faulttolerant flight control (FTFC) system? With regard to reconfigurable control, the identified model should enable the controller to achieve active reconfiguration and restore the control performance. T< o answer these questions, four different global model identification methods and two nonlinear incremental adaptive controllers were developed. Two model identification methods use a parametric model structure namely standard multivariate simplex Bsplines. The focus was placed on how to achieve fast parameter estimation during the research process for these two methods. In the third identification method, a new model structure called tensorproduct simplex Bsplines was extended from a single dimension case to a multidimensional case, with a focus on demonstrating the advantage of this new compound model structure in terms of the flexibility in model structure selection, computational efficiency and approximation power. The fourth method uses a kernel type model structure which is also parametric. The new recursive kernel approach was developed by combining a classical recursive kernel method with a novel support vector regression approach. A model identification method using standard multivariate simplex Bsplines has many advantages, it can avoid the overfitting problem which occurs with an ordinary polynomial method using a triangulation technique. The approximation power of a simplex Bspline based method is determined by the persimplex polynomial order and smoothness order, and can be increased by increasing the density of the subdomains in a triangulation. This simplex Bspline based function approximation method guarantees that its output is bounded by the maximum and minimum Bcoefficients, this facilitates its certification for future real life applications. The linear regression formulation of the simplex Bspline based method allows for applying most of the constrained recursive parameter estimation methods. Furthermore, the simplex Bspline based method has a sparse property, which can lead to high computational efficiency by adopting distributed computation or other modern computing techniques. However, a simplex Bspline method can easily yield a large amount of unknown parameters if the function dimension exceeds 4, which results in a high computational load considering the smoothness maintaining and covariance matrix updating. To enhance the computational efficiency of the model identification methods using simplex Bsplines, two recursive linearregression model identification methods were developed in this thesis: a substitutionbased multivariate simplex Bspline (SBMVSB) method and a recursive sequential multivariate simplex Bspline (RSMVSB) method. In the SBMVSB method, an efficient recursive solver is developed for a constrained linear regression problem when using simplex Bsplines. The constrained linear regression problem is converted into a constraintfree linear regression problem using a general solution for the equality constraints. This transformation was shown to reduce the scale of the identification problem in terms of the number of unknown parameters, and thus the computational load required for the model identification method can be reduced. The RSMVSB method consists of two consecutive procedures at one model evolution step. The first procedure achieves updating of a local model covering the current data point instead of a global model. The requirement of updating a complete covariance matrix is avoided by only updating one local model, and therefore the computational efficiency of this method is greatly enhanced. The second procedure guarantees a smooth transition between this local model and its neighboring local models. The computational complexity of SBMVSB and RSMVSB was given from a mathematician point of view, then, they were validated using simulated flight test data generated using a highfidelity nonlinear model of an F16 aircraft. Simulation results showed that both methods can achieve higher approximation accuracy than ordinary polynomial based methods, and both can be many, e.g. 10, times faster than an equality constraint recursive least squares based MVSB (ECRLSMVSB) method. The second feature of these two methods facilitates their future onboard applications. Tensorproduc< t simplex (TPS) Bsplines provide a compound structure, which provide more flexibility than a standard simplex Bspline model during model structure selection. Using TPS Bsplines, different dimension of inputs can be treated differently depending on their characteristics determined from a priori knowledge. In the work presented in this thesis, the TPS Bspline concept was extended from a single dimension case into a more general multidimensional case. Compared to standard simplex Bsplines, TPS Bsplines can make better use of a priori model knowledge. By reducing many unnecessary basis polynomials from the regression vector, TPS Bsplines have the potential to lead to a lower computational load than standard simplex Bsplines. The TPS Bspline method was validated using a data set generated from a highfidelity nonlinear F16 model. Simulation results showed that TPS Bsplines can yield higher approximation power than standard simplex Bsplines with less Bcoefficients. Two similar recursive parametric kernel methods namely weight varying least squares support vector regression (WVLSSVR) and Gaussian process kernel based LSSVR (GPKLSSVR) were developed for aerodynamic model identification in this thesis. The focus of this work was enhancing the approximation power of a recursive parametric kernel method by choosing an optimal set of kernels for the kernel scheme. An offline method called improved recursive reduced LSSVR (IRRLSSVR) was used to determine optimal kernels for a classical recursive kernel method. The new kernel method was validated using a series of public available benchmark data sets well known to researchers from the field of pattern recognition. GPKLSSVR showed a higher approximation power than WVLSSVR, and both of them showed a higher approximation power than a classical recursive kernel method based on kmeans clustering. A novel type of acceleration measurementsbased incremental flight control laws was investigated with the aim of providing a reconfigurable control unit with a powerful nonconventional flight control approach which could accommodate sudden structural or actuator failures occurring in an aircraft. The preferred modelfree, incremental control approach used in this thesis was the SBB approach, which was initially developed for control designs of nonlinear nonaffineincontrol systems. The SBB approach achieves an accurate reference command tracking performance by approximate dynamic inversion. The SBB approach was extended to deal with sudden model changes in an aircraft caused by structural or actuator failures. A hybrid twoloop angular controller and a joint twoloop angular controller were designed for the RECOVER model. In the hybrid twoloop angular controller, the angular control loop was designed using a nonlinear dynamic inversion (NDI) control law, and the angular rate loop controller using the SBB approach. In the joint twoloop angular controller, the overall controller was designed using a backstepping technique with each loop stabilized recursively. Both angular controllers were validated using the RECOVER model with a focus on dealing with perturbed aircraft flight performance caused by failures. Two benchmark fault scenarios were selected: a rudder runaway case and a flight 1862 engine separation scenario. Simulation results showed that both control setups can guarantee the safety of the postfailure aircraft and achieve a proper reference tracking performance. In comparison with the hybrid NDI/SBB angular controller, the joint SBB angular controller resulted in a better reference tracking performance for the sideslip angle, especially in the engine separation case. An SBB controller contains a time scale parameter, other incremental control laws such as incremental NDI (INDI) and incremental backstepping (IBKS) involve a control effectiveness matrix. Before we can investigate how the time scale parameter or a control effectiveness matrix affect the control performance of an incremental flight controller, the parameter variations of a control effectiveness matrix need to be esti< mated and analyzed. The TPS Bspline method and an immersion and invariance (I&I) method were chosen to estimate a control effectiveness matrix for an F16 aircraft. Although the I&I approach initially was not aimed at high modeling accuracy, it was assumed in this thesis that it is able to estimate the changing trend of the control derivatives. Simulation results showed that TPS Bsplines capture the changes in the control derivatives better than the I&I approach in terms of consistency. For F16, the control effectiveness matrix does not evidently affect the control performance of an incremental flight controller when a flight maneuver is moderate in terms of the variation of angle of attack and airspeed. Further research on modular adaptive reconfigurable control is required, for example incorporating the SBMVSB method or the WVLSSVR method into control designs to further check how well they are suited for modular adaptive control in terms of approximation power and onboard computational efficiency. Further research on acceleration measurements based reconfigurable control should include tests on the SIMONA simulator, realistic testflight with UAV and research aircraft.Flybywire; Aerodynamic model; Adaptive control; Fault tolerant; Reconfiguration; Flight envelope protection; Simplex spline theory+Ipskamp Drukkers, Enschede, The NetherlandsAerospace EngineeringControl and Simulation
51.987, 4.377)uuid:5d83f529e0744a30b00bb11a3d23dabdDhttp://resolver.tudelft.nl/uuid:5d83f529e0744a30b00bb11a3d23dabdURelative Navigation for Satellite Formation Flying based on Radio Frequency MetrologySun, R.Gill, E. (promotor)To increase mission return, utilizing two or more spacecraft instead of one may sometimes be superior. This is especially true when a large spaceborne instrument needs to be created through larger and configurable baselines, such as telescopes and interferometers. However, coordinating the alignment of the individual components of such a spaceborne instrument on separate spacecraft (involving the estimation and control of baselines) will require a high level of accuracy for relative navigation and control. The increasing demand of such science missions or challenges on complex functions such as rendezvous and docking calls for high accuracy levels of ranging at centimeter or even millimeter levels. The objective of this research is to investigate key technologies of developing a relative navigation system based on radiofrequency (RF) metrology. This RFbased system inherits Global Navigation Satellite System (GNSS) technologies through transmission and reception of locally generated GNSSlike pseudo random noise (PRN) ranging codes and carrier phases via intersatellite links. This enables operation, e.g., in high Earth orbits where GNSS constellations are poorly visible. The RFbased navigation system is designed to comprise one transmitter, one receiver and several antennas in order to enable coarsemode intersatellite distance estimation (meter level) based on pseudorange measurements and finemode distance (centimeter level) and lineofsight (LOS) estimation (subdegree level) based on carrier phases in addition to pseudorange. A benchmarking system, called the Formation Flying Radio Frequency (FFRF) sensor, has been successfully shown and demonstrated on PRISMA mission. This research improves the performance of FFRF with respect to the technologies 1) to deal with errors and uncertainties, especially multipath; 2) to perform an unaided, fast and reliable carrier phase integer ambiguity resolution (IAR); and 3) to share channels among multiple spacecraft. Multipath In space applications, receivers on space vehicles may suffer from very short delay multipath (< 4 m), reflected from the vehicle itself or from other vehicles during the operations of rendezvous and docking. The thesis proposes a novel method, termed "Multipath Envelope Curve Fitting", to mitigate veryshortdelaymultipath on pseudorange measurements by approximately 50%. It also exhibits a promising performance for medium or large dela< yed multipath as compared to stateoftheart methods. The method is based on the fact that the signal strength information, reported by early or late correlators inside the receiver, has an inphase correlation with the pseudorange multipath error. By linearly combining multiple signal strength estimators from multiple correlators, the pseudorange multipath error has been accurately estimated. The weights for the linear combination were obtained by curve fitting based on the leastsquares adjustment. A simple implementation strategy was also proposed that enables a receiverinternal multipath estimation process operated in conjunction with the tracking loop with a minimal additional computational overhead. Compared to the pseudorange multipath, the carrier phase multipath has more significant impacts on high precision navigation, especially when it is coupled with the carrier phase IAR. By making use of the signal to noise ratio (SNR) data of multiple antennas, this thesis proposes a novel cascaded extended Kalman Filter (EKF) to mitigate carrier phase multipath. This method accelerates the IAR process significantly and guarantees an achievement of subdegree LOS accuracy. Both realvalued and complexvalued EKF are proposed and evaluated. The complexvalued EKF has been found to be insensitive to poorly defined initial conditions, when the realvalued EKF has difficulties converging. Moreover, the complexvalued EKF has shown better convergence properties for SNR observations with a large amount of noise. Integer Ambiguity Resolution The second challenge of this research is to perform an unaided, fast and reliable carrier phase IAR. Singleepoch IAR algorithms are proposed in this thesis, by making use of a nonlinear quadratic LOS length constraint and taking advantages of antenna arrays. Two methods, namely, the validation method and the subset ambiguity bounding method, are proposed. They replace the equality quadratic constraint by inequality boundaries such that the well known Leastsquares AMBiguity Decorrelation Adjustment (LAMBDA) integer ambiguity resolution process is implemented within a predefined threshold to increase the integer search fidelity. Numerical simulations and field tests demonstrated that both the validation method and the subset ambiguity bounding method provided remarkable improvements with up to 80% higher success rates than the original LAMBDA method based on singleepoch measurements. The validation method showed a slightly better performance than the subset ambiguity bounding method as they differ in utilizing allambiguityset and subsetambiguity, respectively. Better IAR robustness against multipath can also be observed as compared to the original LAMBDA method. An Ambiguity Dilution of Precision (ADOP) measure under the LOS constraint is derived, which is an easytouse and insightful indicator of the ambiguity resolution capability. A ruleofthumb for the predefined threshold has also been derived in the closedform expression, providing guidance on how to choose boundaries according to the noise level and antenna geometry. Multiple Access Technology Enabling multiple access capability is of critical importance for future missions with four or more spacecraft. The Code Division Multiple Access (CDMA) technology is recommended to be used in combination with a flexible role rotating topology in this research. This allows coping with timecritical relative navigation requirements and enables flexible operations during various mission phases. Through realistic formation case studies, the limitation of CDMA was extensively investigated in terms of the multiple access interference (MAI) which could result in a ranging error of several meters and is highly dependent on the Doppler offset. Recommendations are given in this thesis to reduce corresponding MAI errors.Trelative navigation; GNSS; formation flying; multipath; integer ambiguity resolutionSpace System Engineering)uuid:6e1a39dd15814d87b62397d1dc39fb78Dhttp://resolver.tudelft.nl/uuid:6e1a39dd15814d87b62397d1dc39fb78XMicro Ramps in Supe< rsonic Turbulent Boundary Layers: An experimental and numerical studySun, Z.Scarano, F. (promotor)LThe micro vortex generator (MVG) is used extensively in low speed aerodynamic problems and is now extended into the supersonic flow regime to solve undesired flow features that are associated with shock wave boundary layer interactions (SWBLI) such as flow separation and associated unsteadiness of the interaction system. Numerous experimental and numerical studies have shown that despite their small size, such devices can alter the boundary layer properties very efficiently, when compared to the conventional vortex generators. In order to assist a more efficient design of MVGs, fundamental studies have been carried out to understand the associated wake properties such as the increased boundary layer mixing and the structure and stability of the induced vortex system. The present work is conducted in the framework of such fundamental studies. The micro ramp is among the most commonly used MVG devices and has been selected for the present investigations. The research is based both on wind tunnel experiments and numerical simulations in order to build a more comprehensive and detailed understanding of the flow behind a micro ramp immersed in a supersonic turbulent boundary layer. The choice of the experimental approach is justified by the fact that the incoming turbulent boundary layer exhibits a high Reynolds number (Re?=13,600), which makes it too challenging for extensive CFD investigation by using LES or DNS approaches. Variants of the micro ramp configuration as well as the attendant SWBLI can be studied efficiently by wind tunnel experiments adopting PIV as velocity field diagnostics. The use of numerical simulations by the implicit large eddy simulation (ILES) technique for one specific case enables the detailed inspection of the flow field that adds to the understanding of the flow development in regions or aspects where the experimental method provides limited access. Finally, there is general interest to know that till what extent numerical simulations can correctly identify the governing mechanisms of the boundary layer flow manipulation by micro ramps. Tomographic PIV is used as threedimensional flow diagnostic technique in the investigation of flow organization in the micro ramp near wake (x/h?9~15). From the experimental data it is observed that the mean flow features a conical wake containing a pair of steady vortices aligned in streamwise direction. This is considered to be the basic mechanism of the boundary layer flow manipulation, whereas the wallnormal velocity component features a central focussed upwash with downwash motions at the sides. Simultaneously, a deficit region of streamwise velocity is produced in the center of the wake. The shear layer surrounding the wake is subject to KelvinHelmholtz (KH) type instability and the instantaneous flow organization exhibits the formation of coherent KH vortices that are arc shaped and dominate the velocity field fluctuations across the shear layer. Conditional averaging of the 3D velocity field yields the salient features of the interaction between the streamwise vortices and the KH vortices whereas the former are found to be weakened at the generated of KH vortices. The downstream decay of the flow features that are introduced by the micro ramp is relevant to its positioning with respect to the point of interaction between shock wave and boundary layer, indicating the relevance of investigating the further downstream development. Therefore experiments are conducted with large format PIV camera to study the decay in the center plane of the micro ramp far wake (x/h?12~32). In order to find a proper scaling parameter of the micro ramp wake, two geometrically similar micro ramps with different sizes are employed. Both streamwise and wallnormal velocity components exhibit a powerlaw decay in agreement with theories for the fully developed turbulent flow regime. The wallnormal velocity decays faster, approximately at a rate 2.5 times of the momentum deficit. The selfs<imilarity of the velocity profiles is also examined. The streamwise velocity exhibits a good degree of selfsimilarity in the upper and lower shear layer, while the wallnormal component has overlapped upwash profiles. Concerning the turbulent properties, a strong anisotropy of velocity fluctuations is observed at upstream locations (x/h<20), nonetheless both fluctuation components decay to a similar magnitude when approaching the downstream end of the measurement domain (x/h>20). The organization of instantaneous vortical field is also investigated in the attempt to better understand their effect on the wake decay. Spatial autocorrelation of the instantaneous velocity fields yields the streamwise evolution of the average distance between vortices. Vortex pairing is identified in the range x/h=18~22 through an increase of such distance. The detection of counterrotating vortices in the lower part of the wake suggests that the KH vortices produced in the upper region of the shear layer propagate into the region close to the wall after vortex pairing, which eventually gives rise to ringvortex formation in the later stage of the wake. A numerical study using ILES with high order scheme is carried out in collaboration with the University of Texas at Arlington. In order to establish a fair comparison with the experimental data, the flow conditions are made as similar as possible, matching the free stream Mach number and the ratio between micro ramp height and boundary layer thickness. The attendant limitations on computational resources limit the Reynolds number based on boundary layer momentum thickness to about onethird of that in the experiments. The comparison covers the most relevant quantities, such as the streamwise and wallnormal velocity and the peak vorticity. An overall good agreement is observed. A noticeable discrepancy involves underestimation of upwash motion: the wallnormal velocity amounts to 70% of the measured data. In the observation of instantaneous flow, vortex pairing is also identified and the spatialtemporal evolution of the KH vortex is studied by tracking, which confirms the flow model conjectured from the planar PIV study in the center plane.\turbulence; flow control; Particle Image Velocimetry; Large Eddy Simulation; supersonic flow'Aerodynamics Wind Energy and Propulsion)uuid:3de5fc36dd994d59972a9b172a8c8b2eDhttp://resolver.tudelft.nl/uuid:3de5fc36dd994d59972a9b172a8c8b2e7Monolithically Inegrated Silicon Bipolar RF OscillatorsSun, Y.Beats, R.G.F. (promotor)+Silicon bipolar RFIC; Microwave oscillators8Electrical Engineering, Mathematics and Computer Science
*+&ffffff?'ffffff?(?)?"dXX333333?333333?U}}}}}}}}}} }
}}}
}}}}}}}}}}}}
@
!
"
#
$
%
&
'@
(
)
*
+
,

.
/@
0
1
2
3
4
5
6@
7
8
9
:
;
<
=
>@
?
@
A
B
C
D
E@
F
G
H
I
J
K
L
M@
N
O
P
Q
R
S
T
U
Vx@
W
X
Y
Z
[
\
]
^
_
`
a x@
b
c
Z
d
e
f
g
h
i
x@
j
k
Z
l
m
n
o
p
q<@
r
s
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~>@ddyKyKhttp://resolver.tudelft.nl/uuid:af94d53518534a6c8b3f77c98a52346ayKyKhttp://resolver.tudelft.nl/uuid:edf396c55c3a4b5c9fc4b8bb5ff6eeeeyKyKhttp://resolver.tudelft.nl/uuid:37d758b5bf354a3483c9235008eaf116yKyKhttp://resolver.tudelft.nl/uuid:7fe64dde7fb543928160da6f7916dc6byKyKhttp://resolver.tudelft.nl/uuid:e83b184cc972402aa0c6418222cf11adyKyKhttp://resolver.tudelft.nl/uuid:11717f7d51c9471b8f9eee1a70e7f032yKyKhttp://resolver.tudelft.nl/uuid:d5a91375c9954dcfb499c593b80ceac1yKyKhttp://resolver.tudelft.nl/uuid:89455d9afb3842bfb1db03a8a5104bcf yKyKhttp://resolver.tudelft.nl/uuid:5d83f529e0744a30b00bb11a3d23dabd
yKyKhttp://resolver.tudelft.nl/uuid:6e1a39dd15814d87b62397d1dc39fb78yKyKhttp://resolver.tudelft.nl/uuid:3de5fc36dd994d59972a9b172a8c8b2egg
Root Entry FUU@SummaryInformation( F<Workbook F7DocumentSummaryInformation8 F
!"#$%&'()*+,./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{}~