Search results for "observer"
showing 10 items of 345 documents
A "imunidade soberana" de Pinochet contestada
2000
Um observador privilegiado e participante do processo que levou à quebra da "imunidade soberana" do ex-ditador chileno Augusto Pinochet expõe como e em nome do que isso ocorreu. A privileged observer of, as well as a participant in, the process that resulted in the breaking of the "sovereign immunity" of Chiles former dictator Augusto Pinochet tells how and in the name of what this happened.
State Estimation of a Nonlinear Unmanned Aerial Vehicle Model using an Extended Kalman Filter
2008
An Extended Kalman Filter is designed in order to estimate both state variables and wind velocity vector at the same time for a non conventional unmanned aircraft. The proposed observer uses few measurements, obtained by means of either conventional simple air data sensors or a low cost GPS. To cope with the low rate of the GPS with respect to the other sensors, the EKF algorithm has been modified to allow for a dual rate measurement model. State propagation is obtained by means of an accurate six degrees of freedom nonlinear model of the aircraft dynamics. To obtain joint estimation of state and disturbance, wind velocity components are included in the set of the state variables. Both stoc…
Descriptor-type Kalman Filter and TLS EXIN Speed Estimate for Sensorless Control of a Linear Induction Motor.
2014
This paper proposes a speed observer for linear induction motors (LIMs), which is composed of two parts: 1) a linear Kalman filter (KF) for the online estimation of the inductor currents and induced part flux linkage components; and 2) a speed estimator based on the total least squares (TLS) EXIN neuron. The TLS estimator receives as inputs the state variables, estimated by the KF, and provides as output the LIM linear speed, which is fed back to the KF and the control system. The KF is based on the classic space-vector model of the rotating induction machine. The end effects of the LIMs have been considered an uncertainty treated by the KF. The TLS EXIN neuron has been used to compute, in …
Observer-based control design for a class of nonlinear systems subject to unknown inputs: LMI approach
2015
This paper deals with the problem of observer-based controller design for a class of nonlinear systems subject to unknown inputs. A novel method is presented to design a controller using estimated state variables which guarantees all the state variables of the closed-loop system converge to the vicinity of the origin and stay there forever. This is done via satisfying several sufficient conditions in terms of nonlinear matrix inequalities. In light of linear algebra, particularly matrix decompositions, the achieved conditions will be converted to a Linear Matrix Inequality (LMI) problem to facilitate the procedure of computing the observer and controller gains. Finally, the effectiveness of…
Improving the speed estimation by load torque estimation in induction motor drives: an MRAS and NUIO approach
2021
This paper proposes the application of the NUIO inside a FOC induction motor drive for the simultaneous estimation of the load torque and the rotor speed. The idea is to estimate at first the speed with the current model in parallel with a reference model developed on the basis of the voltage model of the induction machine. Then, the estimated speed is given as input to a nonlinear unknown input observer (NUIO) to estimate the load torque. This estimation is then used to correct the previous estimation of the speed. Simulation and experimental results confirm the goodness of the method for an extended range of speed and different load torque, and they confirm the reduction of error in trans…
Reliability of physical functioning measures in ambulatory subjects with MS.
2005
Background and Purpose. One of the primary reasons for measuring outcomes during rehabilitation is to determine the effect of physiotherapy. Repeated measurement situations are susceptible to several sources of error, including inconsistencies caused by the subject, the procedure, the instrument and the examiner. Therefore, the reliability of the measures needs to be examined. Method. The present study used a repeated-measures design. Two studies were undertaken to examine the test–retest and inter-rater reliability for physical functioning measures. The interval between the measurements was one week. The sample consisted of 19 ambulatory subjects with mutliple sclerosis (MS) in the test–re…
Contour/Outline/Silhouette
2020
The contour is the locus at which the parts of opaque solid objects appear to form an edge because it corresponds for the viewer to the projection of the rim, namely the curve that divides the surfaces into visible and invisible parts. The rim between the visible front and the invisible rear side is projected onto the contour that is the envelope of all the curves of equal depth. Although the rim and the contour run into depth, they are distinct concepts that regard the object-centred and the viewer-centred description. The outline is the boundary of the surface delimited by the contour, which fills a spatial region. Rubin (1921) discovered the property that allows the contour and the outli…
Novel method and instruments for the optimal techno-economic sizing of borehole heat exchangers
2021
El test de respuesta térmica (TRT) es ampliamente utilizado como método estándar para caracterizar las propiedades térmicas del terreno adyacente a un intercambiador de calor enterrado (BHE). Los métodos tradicionales para interpretar los resultados aplican soluciones analíticas o numéricas asumiendo que el terreno es infinito, homogéneo e isotrópico. Sin embargo, en realidad el subsuelo presenta generalmente una estructura estratificada y heterogénea, y por lo tanto las propiedades térmicas pueden variar sustancialmente con la profundidad. En este sentido y con la intención de resolver las limitaciones del TRT estándar, la presente tesis doctoral se centra en el desarrollo de métodos e ins…
Robust fault detection design for unknown inputs Takagi-Sugeno models with parametric uncertainties and time-varying delays
2014
This paper deals with the design of robust fault detection system for Takagi-Sugeno (T-S) modes with parametric uncertainties and time-varying delay. An Unknown Input Observer (UIO) is designed such that the unknown inputs are thoroughly decoupled from residual signals while they show the maximum possible sensitivity to the faults and the minimum possible sensitivity to the external disturbances. Since the system under consideration is subjected to parametric uncertainties, the H ∞ model matching approach is used to design an optimal observer. Design procedure is given in terms of Linear Matrix Inequalities (LMIs). Finally, a numerical example is presented to show the effectiveness of the p…
"Would I run the pub if I won the Lottery? No." : a study on how ordinary people are constructed and described in British supplement magazines
2012
Tavallisten ihmisten rooli ja näkyvyys mediassa on lisääntynyt teknologiavälitteisen ja sosiaalisen median myötä nyky-yhteiskunnassa. Tavallisten ihmisten rooli on muuttunut sosiaalisessa mediassa yleisöstä esiintyjäksi, kun taas perinteisessä lehtijournalismissa he edelleen kuuluvat vähemmistöön. Tämän tutkielman tavoitteena on selvittää, minkälaisia human interest -tarinoita tavallisista ihmisistä kerrotaan ja minkä takia ne ovat valittu julkaistavaksi. Lisäksi tavoitteena on tutkia hyödyntäen Bellin (1991) uutisteksteille suunnattua rakennemallia, miten ja mistä osista tarinat rakentuvat narratiivisesti. Samalla kartoitetaan, mitä tyypillisiä aihealueita tavallisten ihmisten tarinoissa t…