Dissertations / Theses on the topic 'Perturbation externe'
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Rao, Guillaume. "Biomécanique de la coordination motrice : Modélisations et analyses en réponse à une perturbation interne ou externe." Phd thesis, Aix-Marseille Université, 2006. http://tel.archives-ouvertes.fr/tel-00908210.
Corbeil, Philippe. "Études des mécanismes adaptatifs du maintien de l'équilibre orthostatique. Effets d'une fatigue musculaire, d'une douleur expérimentale et d'une perturbation externe." Thesis, Université Laval, 2003. http://www.theses.ulaval.ca/2003/21104/21104.pdf.
Corbeil, Philippe. "Etude des mécanismes adaptatifs du maintien de l'équilibre orthostatique : effets d'une fatigue musculaire, d'une douleur expérimentale et d'une perturbation externe." Université Joseph Fourier (Grenoble), 2003. http://www.theses.fr/2003GRE10062.
Chatagnon, Thomas. "Standing balance recovery strategies following external perturbations : a multiscale approach with applications to dense crowds." Electronic Thesis or Diss., Université de Rennes (2023-....), 2023. http://www.theses.fr/2023URENE007.
Every year, several crowd accidents are reported around the world. These accidents can result in injuries and even fatalities. One of the triggering element of these accidents has been reported to result from falls associated with loss of standing balance in this dense crowd context. However, knowledge regarding human standing balance in dense crowd is very limited due the complex nature of this environment. In this thesis we proposed an experimental approach to study standing balance recovery of individuals following external perturbations in environments with different crowd density. In particular, as perturbation may occur from any direction in dense crowds we first study the reaction to single individuals to external perturbations arising from different directions. Based on the data collected during of this experiment, we were able to propose a method to predict participants’ recovery strategies following external perturbations based on kinematic information. Experiment involving multiple individuals were then considered. In particular, we study the effect of the crowd density on the initiation and the characteristics of recovery steps. Eventually, a novel experimental paradigm was proposed to study standing balance during real crowded events. This approach was then used within punk rock concert crowds. Results provided new insights regarding the physical interactions and recovery strategies observed in this context
Zhang, Lei. "Rapid motor responses to external perturbations during reaching movements." Diss., Ludwig-Maximilians-Universität München, 2015. http://nbn-resolving.de/urn:nbn:de:bvb:19-184803.
Bouattour, Jouda. "Etude des perturbations électromagnétiques externes et internes engendrées sur du matériel ferroviaire RATP." Paris 6, 1986. http://www.theses.fr/1986PA066200.
Pollock, Courtney L. "Motor control of response to external perturbations in people post-stroke." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/51595.
Medicine, Faculty of
Graduate
Beretta, Victor Spiandor [UNESP]. "Ajustes posturais sob perturbação externa em indivíduos com doença de Parkinson e neurologicamente sadios." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/151770.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Introdução: A manutenção da postura emprega mecanismos de controle preditivos e reativos. Indivíduos com doença de Parkinson (DP) apresentam declínio no controle postural, principalmente na presença de perturbações externas. O uso de informações adicionais sobre a perturbação postural parece ser eficiente para melhorar o controle postural de idosos neurologicamente sadios, porém, na DP ainda é pouco conhecido. Objetivos: a) comparar as respostas dos ajustes posturais preditivos e reativos em idosos neurologicamente sadios (GC) e com DP (Estudo 1); b) verificar o efeito do fornecimento de informações adicionais nos ajustes posturais preditivos e reativos (Estudo 2). Metodologia: Participaram do Estudo 1, 39 (19 com DP e 20 GC) e do Estudo 2, 36 (17 com DP e 19 GC) selecionados na comunidade. Os indivíduos ficaram em pé sobre um equipamento que provocou a perturbação pelo deslocamento da base de suporte com intensidade de 15 cm/s e deslocamento de 5 cm. A perturbação inesperada foi apenas a primeira tentativa e, posteriormente, foram realizadas mais 15 tentativas em que apenas 5 ocorreram a perturbação de maneira imprevisível para análise da habituação à tarefa (Estudo 1). Para o Estudo 2 foram realizadas 20 tentativas com o fornecimento de informações adicionais sobre a perturbação, visual, verbal e somatossensorial do músculo requerido. Os dados EMG e CoP na condição inesperada foram analisados por meio de ANOVA one-way e nas perturbações imprevisíveis (Estudo 1 e 2) por meio de ANOVAs two-way. Resultados: Na perturbação inesperada, os idosos com DP apresentaram maiores valores nos parâmetros da EMG e do CoP em relação ao GC. Na habituação à perturbação, os idosos com DP adaptaram os padrões nos ajustes posturais reativos de forma tardia quando comparados ao GC. Em relação ao efeito das informações adicionais no controle postural, os idosos com DP apresentaram menor oscilação do CoP nos ajustes posturais preditivos em todas as condições de informações quando comparados ao GC. Já o GC aumentou a oscilação do CoP nos ajustes preditivos, considerando as mesmas condições. Nos ajustes posturais reativos, ambos os grupos apresentaram efeitos positivos das informações verbais e somatossensoriais, diminuindo os parâmetros temporais, de amplitude da EMG e espaciais do CoP em relação ás tentativas sem o seu fornecimento ou com o as demais informações (sobre a perturbação e visual). Além disso, os idosos com DP apresentaram controle postural mais adequado quando fornecida informação somatossensorial em relação às demais informações. Por fim, apesar das alterações positivas nos ajustes reativos, os idosos com DP apresentaram maior coativação muscular e tempo para recuperar a posição estável em relação ao GC. Conclusão: Idosos com DP possuem pior controle postural em situações com perturbações externas inesperada e imprevisível, evidenciando alterações temporais, na amplitude da EMG e espaciais do CoP. Além disso, idosos neurologicamente sadios e com DP conseguem alterar os padrões dos ajustes posturais com a exposição de perturbações externas, porém, na DP essa habituação é mais atrasada. As informações adicionais somatossensoriais parecem ter efeito positivo no controle postural dos idosos, principalmente na DP, diminuindo os parâmetros EMG e do CoP nos ajustes preditivos e reativos.
Introduction: Predictive and reactive postural mechanisms are necessary to maintain the posture. Patients with Parkinson's disease (PD) have a decline in postural control, mainly when occur an external perturbation. The use of additional information about the postural perturbation seems to be efficient to improve the postural control of neurotypical older people, but in PD it is still unclear. Aims: a) To compare the predictive and reactive postural adjustments responses in the neurotypical older people (CG) and the PD patients (Study 1); b) To verify the effect of additional information on predictive and reactive postural adjustments (Study 2). Methods: Participated thirty-nine (19 with PD and 20 GC) in the Study 1 and 36 (17 with PD and 19 GC) in the Study 2, selected in the community. The individuals stood on equipment that caused the perturbation by the displacement of the support base with the velocity of 15 cm/s and the range of 5 cm. The unexpected perturbation was the first trial, and 15 trials were realized in which in just 5 occurred the unpredictably perturbation to analyze the habituation to the task (Study 1). In the Study 2, 20 trail were realized with the additional information about the perturbation characteristics, visual, verbal, and somatosensory of the required muscle. The EMG and CoP data in the unexpected condition were analyzed by ANOVA one-way and in the unpredictable perturbations (Study 1 and 2) by the ANOVAs two-way. Results: In the unexpected perturbation, the PD patients presented higher temporal, range of EMG and spatial of CoP in relation to the CG. For the habituation to the perturbation, the patients with PD adapted the patterns in the reactive postural adjustments of delayed form when compared to the GC. In relation to the effect of the additional information on postural control, the PD patients presented lower CoP oscillation in the predictive postural adjustments in all the information conditions when compared to the CG. The GC increased the CoP oscillation in the predictive adjustments, considering the same information conditions. Both groups presented positive effects of verbal and somatosensory information in the reactive postural adjustments, decreasing temporal, range of EMG and spatial parameters of CoP in relation to trial without the information or with other information (about perturbation and visual). In addition, the PD patients presented more adequate postural control when somatosensory information was provided in relation to the other information. Finally, despite of the improvement in the reactive adjustments, patients with PD have a greater muscular coactivation and time to recover the stable position in relation to the CG. Conclusion: Patients with PD have worse postural control in situations with unexpected and unpredictable external perturbation, evidencing changes in the temporal, range of EMG and spatial of CoP parameters. In addition, neurotypical older people and PD patients can change the patterns of postural adjustments with the exposure of external perturbation, but in PD this habituation is more delayed. Besides that, somatosensory information seems to have a positive effect on the postural control of the older people, mainly in the PD, decreasing the EMG and CoP parameters in the predictive and reactive postural adjustments.
FAPESP: 2016/00503-0
CNPq: 159381/2015-0
Cervantes, Chia Carlos Andres, and Weronika Maria Lewandowska. "Optical Characterization of Quantum-Dots-in-a-Well Infrared Photodetectors Under External Perturbations." Thesis, Halmstad University, School of Information Science, Computer and Electrical Engineering (IDE), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-1659.
In this project we have used Fourier transform infrared spectroscopy to study the photoresponse of two different types of quantum dot-in-a-well infrared photodetectors (DWELL QDIPs). The basic task was to compare the photoresponse of these two detectors, and to study the influence of external resonant laser pumping on the photoresponse. Series of measurements were done at 77K. In the first measurements we investigated the photoresponse for different applied voltages at 77K.
In a second run of experiments, we used a 1064 nm infrared semiconductor laser to resonantly
pump the fundamental transition of the quantum dots. The results show that by using this
additional illumination the photoresponse was dramatically increased by creating additional
charge carriers in the quantum dots. This could be used to increase the sensitivity of infrared
detectors based on QDs.
Keil, Julian [Verfasser]. "Use your illusion : audiovisual perception and external perturbation are influenced by oscillatory activity / Julian Keil." Konstanz : Bibliothek der Universität Konstanz, 2012. http://d-nb.info/1026012759/34.
Berseth, Claude-Albert. "Le laser à semiconducteur à cavité externe courte : conception, réalisation et étude de ses perturbations par des réflexions optiques /." [S.l.] : [s.n.], 1994. http://library.epfl.ch/theses/?nr=1242.
Rainone, Corrado. "Following the evolution of metastable glassy states under external perturbations : compression and shear-strain." Thesis, Paris, Ecole normale supérieure, 2015. http://www.theses.fr/2015ENSU0051/document.
We consider the adiabatic evolution of glassy states under external perturbations. Although the formalism we use is very general, we focus here on infinite-dimensional hard spheres where an exact analysis is possible. We consider perturbations of the boundary, i. e. compression or (volume preserving) shear-strain, and we compute the response of glassy states to such perturbations: pressure and shear-stress. We find that both quantities over shoot before the glass state becomes unstable at a spinodal point where it melts into a liquid (or yields). We also estimate the yield stress of the glass. Finally, we study the stability of the glass basins towards breaking into sub-basins, corresponding to a Gardner transition. We find that close to the dynamical transition, glasses undergo a Gardner transition after an infinitesimal perturbation. We then study the high-pressure and high-strain regime beyond the Gardner transition
Dogbe, Kokouvi E. "Etude des anomalies introduites par des perturbations électromagnétiques parvenant sur des bus d'informations reliant un microprocesseur à une mémoire externe." Lille 1, 1994. http://www.theses.fr/1994LIL10089.
Burch, Charmita P. "The extent of perturbation of skin models by transdermal penetration enhancers investigated by ³¹P NMR and fluorescence spectroscopy." unrestricted, 2007. http://etd.gsu.edu/theses/available/etd-04252007-133030/.
Title from thesis title screen. Author's name from thesis title screen. Jerry C. Smith, committee chair; Kathryn Grant, Stuart Allison, committee members. Electronic text (148 p. : ill. (some col.)) : digital PDF file. Description based on contents viewed October 5, 2007. Includes bibliographical references (p. 124-148).
Burch, Charmita Patricia. "The Extent of Perturbation of Skin Models by Transdermal Penetration Enhancers Investigated by 31P NMR and Fluorescence Spectroscopy." Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/chemistry_diss/11.
Claudino, Renato. "Ajustes posturais antecipatórios e compensatórios em idosos ativos submetidos a perturbações laterais da postura." Universidade do Estado de Santa Catarina, 2012. http://tede.udesc.br/handle/handle/244.
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
With advancing age, the human body suffers morphological and functional changes, which lead the postural instability in elderly people. And an important factor in this, are linked to the inappropriate uses of postural adjustments strategies: anticipatory postural adjustment (APA) and compensatory postural adjustments (CPA). Such strategies deal with an ability to respond effectively to a possible loss of balance and minimize the negative consequences of it. Although the difficulties in maintaining balance in the elderly to be known, strategies of postural adjustment, in the face of external perturbations are still scarce. Therefore, the aim of this study was to investigate the APAs and CPAs and their inter-relationships in groups of elderly with and without falls. For this purpose, two groups of 20 elderly participants (with and without history of falls) and 20 young subjects received external perturbations of posture in the frontal plane, through the impact of a pendulum on the right shoulder of the individuals in the standing position, under two conditions: unpredictable and predictetable. The electromyography activity (EMG) of lateral ventral and dorsal postural muscles by recording and integrated (∫EMG) in the typical windows for these strategies, and displacement of body center of pressure (COP). The postural disturbance occurred in the medial-lateral direction, through the impact of a pendulum on the right shoulder of individuals under two conditions: unpredictable and predictable. The results showed the elderly groups (with and without falls) had, in general, smaller amplitude activation (∫EMG) of the CPAs to the dorsal and lateral studied in the unpredictable conditions. The elderly showed changes in the pattern of synergistic lateral muscles compared to the group of young individuals. There was a greater COP displacement in the predictable condition provided for groups of elderly patients with falls compared to the young. The results of this study indicate that the decrease in muscle activity in the elderly groups against disturbances of posture, especially the lateral muscles, may leave these individuals susceptible to falls. Therefore, research and training programs/training or treatment designed to restoring balance in the elderly by improving the activation of the lateral muscles must be developed.
Com o avançar da idade, o corpo humano sofre alterações morfológicas e funcionais, que acarretam grande instabilidade postural em idosos. E um fator importante desta, esta vinculada ao uso inadequado das estratégias de ajustes posturais: o ajuste postural antecipatório (APA) e compensatório (APC). Essas estratégias tratam da capacidade de um indivíduo em responder efetivamente a uma possível perda de equilíbrio. Embora, a dificuldade na manutenção do equilíbrio em idosos seja conhecida, estudos sobre as estratégias de ajuste postural frente a perturbações externas da postura nessa população ainda são escassos. Portanto, o objetivo desse estudo foi investigar os APAs e CPAs e suas inter-relações em idosos com e sem quedas. Para tanto, dois grupos de 20 idosos cada (sem e com histórico de quedas) e 20 indivíduos jovens receberam perturbações externas da postura no plano frontal, através do impacto de um pêndulo no ombro direito dos indivíduos na posição em pé, sob condições não prevista e prevista. As atividades eletromiográficas dos músculos posturais laterais, ventrais e dorsais foram registradas e integradas (∫EMG) nas janelas de tempo típicas para as estratégias de ajuste postural assim como o deslocamento do centro de pressão corporal (COP). De forma geral, os dois grupos de idosos apresentaram, menor amplitude de ativação (∫EMG) muscular nas janelas dos APCs para os músculos laterais e dorsais na condição não prevista. Idosos também apresentaram alteração no padrão sinérgico dos músculos laterais quando comparados ao grupo de indivíduos jovens. Houve um maior deslocamento do COP na condição prevista para os grupos de idosos com quedas quando comparados aos jovens. Os resultados desse estudo indicam que a diminuição da atividade muscular nos grupos de idosos frente a perturbações da postura, especialmente dos músculos laterais, podem deixar esses indivíduos suscetíveis a quedas. Portanto, investigações e programas de treinamento/tratamento que visam treinar ou restabelecer o equilíbrio em idosos melhorando a ativação dos músculos laterais devem ser desenvolvidos.
Zhang, Lei [Verfasser], and Andreas [Akademischer Betreuer] Straube. "Rapid motor responses to external perturbations during reaching movements : experimental results and modelling / Lei Zhang. Betreuer: Andreas Straube." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2015. http://d-nb.info/1076242987/34.
MAGUIÑA, PALMA MISAEL ERIKSON 821875, and PALMA MISAEL ERIKSON MAGUIÑA. "La teoria generalizada de perturbacion para solitones en potenciales externos." Tesis de doctorado, Universidad Autónoma del Estado de México, 2020. http://hdl.handle.net/20.500.11799/105570.
Se estudio la dinámica de interacción de solitones perturbados de la ecuación no lineal de Shrödinguer (nonlinear Schrödinger equation-NLSE), basado en la aproximación adiabática de los parámetros de la solución perturbada. La dinámica de un solitón se estudia aplicado dos perturbaciones: la primera con tasa de crecimiento y decrecimiento, la segunda con el potencial de oscilador armónico. En el primer caso de perturbación la amplitud del solitón encontrada varia exponencialmente, en el segundo caso la solución muestra un comportamiento oscilatorio. También se estudia a la dinámica de interacción para dos solitones y las fuerzas entre ellos. Sin perturbación la interacción de dos solitones en fase es atractiva y puede resultarse en formación de un estado ligado, esta solución tiene comportamiento periódico con oscilaciones de la amplitud y velocidad de solitones. Fuera de fase la interacción de solitones es repulsiva, no formando un estado ligado. El potencial de oscilación armónica mantiene los solitones confinados dentro del potencial y evoca su interacción periódica.\\ En la investigaci\'{o}n encontramos la solución analítica del problema de interacción de solitones de la NLSE en los sistemas con pérdidas o ganancias distribuidas. Los resultados analíticos proporcionan un excelente control cualitativo y cuantitativo de los resultados de las simulaciones numéricas conocidas hasta ahora. El resultado no trivial y inesperado consiste en el hecho de que la separación relativa de solitones dependen de las ganancias o pérdidas de amplificación. Al utilizar la interacción complementaria entre los experimentos informáticos directos y la teoría generalizada de perturbación del solitón adiabático de Karpman-Solov'ev, encontramos fórmulas empíricas notables que describen completamente, cualitativamente y cuantitativamente, el impacto de las pérdidas distribuidas y la ganancia en los escenarios de interacción de los solitones del NLSE.
PNPC, CONACYT
Gourdeau, Justine. "Le sulfure de diméthyle et ses produits d'oxydation atmosphériques en zone cotière méditerranéenne : impact des perturbations anthropiques." Grenoble 1, 1999. http://www.theses.fr/1999GRE10099.
Tokur, Dario Sinan [Verfasser], Andre [Akademischer Betreuer] Seyfarth, and David [Akademischer Betreuer] Lee. "Responses to External Perturbations in Selected Human Motor Tasks - A Systematic Review and Analysis. / Dario Sinan Tokur ; Andre Seyfarth, David Lee." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2019. http://d-nb.info/1201820480/34.
Ennaji, Hasna Sara. "The effect of external perturbations on the reactive balance response of young and older women in a simulated real-world context: public transportation." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
Malloni, Wilhelm Massimiliano [Verfasser], and Hans Robert [Akademischer Betreuer] Kalbitzer. "AUREMOL-QTA, a program package for NMR based automated recognition and characterization of local and global conformational changes in proteins induced by ligand binding as external perturbation / Wilhelm Massimiliano Malloni. Betreuer: Hans Robert Kalbitzer." Regensburg : Universitätsbibliothek Regensburg, 2011. http://d-nb.info/1030178836/34.
Hu, Wei. "Identification de paramètre basée sur l'optimisation de l'intelligence artificielle et le contrôle de suivi distribué des systèmes multi-agents d'ordre fractionnaire." Thesis, Ecole centrale de Lille, 2019. http://www.theses.fr/2019ECLI0008/document.
This thesis deals with the parameter identification from the viewpoint of optimization and distributed tracking control of fractional-order multi-agent systems (FOMASs) considering time delays, external disturbances, inherent nonlinearity, parameters uncertainties, and heterogeneity under fixed undirected/directed communication topology. Several efficient controllers are designed to achieve the distributed tracking control of FOMASs successfully under different conditions. Several kinds of artificial intelligence optimization algorithms andtheir modified versions are applied to identify the unknown parameters of the FOMASs with high accuracy, fast convergence and strong robustness. It should be noted that this thesis provides a promising link between the artificial intelligence technique and distributed control
Лазаренко, Артем Александрович. "Синтез и разработка инвариантных систем стабилизации основного вооружения танков." Thesis, НТУ "ХПИ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/22727.
The thesis for the degree of candidate of technical sciences, specialty 05.13.03 – Systems and management processes. – National Technical University "Kharkov Polytechnic Institute", Kharkov – 2016. The thesis is dedicated to development analog and digital invariant guidance systems and stabilize the main armament of tanks through the creation of mathematical models perturbed motion tank gun relative to the axis of the pins and the tank tur ret gun relative to the axis of rotation, as well as simulation models of external disturbances acting on the main armament channels vertical and horizontal guidance. It is shown that increasing the degree of invariance closed stabilization system to external perturbations lead to lower stability margin closed system. To maintain the desired stability margin suggested the introduction of the system of additional feedback path for the angular acceleration of the object of stabilization. The features invariant digital stabilization system tank gun, including the need to use a digital low-pass filter Batteruorta and Lanczos filtering high frequency noise output signals of sensors. It is proved that the construction of a digital stabilizer tank cannon appropriate series-parallel use of digital filters Batteruorta and Lanczos. The structure created and the choice of variable constants stabilization algorithms was made that provide an invariance closed system of guidance and stabilization without significantly reducing its stability margin. Modeling of guidance and stabilization in a closed system with subsequent analysis of these processes suggests a significant increase in accuracy working off of external perturbation (at 1.8 – 1.9 times) compared with the standard.
Лазаренко, Артем Олександрович. "Синтез і розробка інваріантних систем керування наведенням та стабілізацією основного озброєння танків." Thesis, НТУ "ХПІ", 2016. http://repository.kpi.kharkov.ua/handle/KhPI-Press/22726.
The thesis for the degree of candidate of technical sciences, specialty 05.13.03 – Systems and management processes. – National Technical University "Kharkov Polytechnic Institute", Kharkov – 2016. The thesis is dedicated to development analog and digital invariant guidance systems and stabilize the main armament of tanks through the creation of mathematical models perturbed motion tank gun relative to the axis of the pins and the tank tur ret gun relative to the axis of rotation, as well as simulation models of external disturbances acting on the main armament channels vertical and horizontal guidance. It is shown that increasing the degree of invariance closed stabilization system to external perturbations lead to lower stability margin closed system. To maintain the desired stability margin suggested the introduction of the system of additional feedback path for the angular acceleration of the object of stabilization. The features invariant digital stabilization system tank gun, including the need to use a digital low-pass filter Batteruorta and Lanczos filtering high frequency noise output signals of sensors. It is proved that the construction of a digital stabilizer tank cannon appropriate series-parallel use of digital filters Batteruorta and Lanczos. The structure created and the choice of variable constants stabilization algorithms was made that provide an invariance closed system of guidance and stabilization without significantly reducing its stability margin. Modeling of guidance and stabilization in a closed system with subsequent analysis of these processes suggests a significant increase in accuracy working off of external perturbation (at 1.8 – 1.9 times) compared with the standard.
Hamadi, Hussein. "Fault-tolerant control of a multirotor unmanned aerial vehicle under hardware and software failures." Thesis, Compiègne, 2020. http://www.theses.fr/2020COMP2555.
The aim of this work is to propose mechanisms for multirotor drones that allow, on the one hand, to tolerate faults on the drone, and on the other hand to take into account the effects of the wind outdoors. The faults targeted include fault in actuators, sensors, but also software faults on the data fusion algorithms. ln our work, we have developed a robust controller and an exterior disturbance observer capable of cooperating with th, contrai reconfiguration method, to simultaneously tolerate motor failures and exterior wind disturbances through active fault tolerance techniques… We have also proposed a new technique for tolerating actuator faults for a coaxial octorotor drone. This technique is based on a robust command law with reconfigurable "self tuning sliding mode control (STSMC)" gains, where the control gains are readjusted according to the detected error in order to maintain the stability of the system. lndoor experiments are conducted to show and compare our solution with two other fault tolerance techniques. The efficiency and behavior of each method are studied after successive fault injections into the actuators. The main advantages and disadvantages of each method are deduced by analyzing the results obtained. Additionally, we provide an approach for fault tolerance of drone data fusion sensors and software mechanisms. This approach is based on the redundancy of sensors and the diversification of software components
Петренко, Олексій Володимирович. "Удосконалення методів підвищення точності вібраційного гіроскопа з металевим циліндричним резонатором." Thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/36992.
Дисертаційна робота присвячена науковому обґрунтуванню та розробці алгоритмів компенсації внутрішніх похибок та зовнішніх збурень у Коріолісовому вібраційному гіроскопі, а також удосконаленню його складових частин (резонатора, чутливого елементу). Автором розроблено методику та обладнання для робочого місця безелектродного вимірювання динамічних параметрів металевого резонатора після його виготовлення, розроблено конструкцію приладдя для приклеювання п’єзоелектродів до резонатора нової конструкції, методику та обладнання робочого місця для балансування мас. Розроблено та відпрацьовано на експериментальному зразку КВГ методики температурної корекції фаз сигналів квадратури та кутової швидкості, багатопараметричної корекції дрейфу нуля і масштабного коефіцієнту, що призводить до збільшення точності виміру кутової швидкості в умовах дії температурних градієнтів.
In the thesis the following new scientific results are obtained: 1. For the first time, a multi-parameter method of CVG scale factor correction is developed and implemented, which can be used during the CVG operation in the rate and in the differential modes. Ukraine patent have been obtained for this method. 2. Scientifically grounded analysis of a new design of a cylindrical resonator with holes on the walls of a cylinder having higher vibration resistance was first developed and carried out. 3. The multiparameter bias correction algorithm has been developed and implemented, which has advantages over the existing ones by accuracy. 4. For the first time experimental researches were carried out on a manufactured experimental sample of CVG with developed metal cylindrical resonator made of elenvar elloy, which showed high accuracy scale factor and bias drift correction under the action of temperature gradient, as well as high shockvibration resistance of the sample. The practical significance of thesis results are: − comparison of two designs of metallic cylindrical resonators with holes on the bottom and on the wall of the cylinder and by calculations and computer simulation the advantages of the second design over the first one in the part of shock resistance have been substantiated; − аn analysis of the different geometries of the holes has been made. Their influence on the resonant oscillation frequencies of a cylindrical resonator is revealed. Recommendations for the geometry of the resonator and its elements have been developed; − improved design of the base on which the newly designed resonator with holes on the wall of the cylinder is installed; − the choice of electrodes used for oscillation excitation and measurement of the signals is experimentally substantiated; − the technique and equipment for workplace electrodeless measurement of metallic resonator dynamic parameters after its manufacture have been developed; − the influence of frequency mismatch, wave angle and positioning errors of the electrodes on the CVG bias and scale coefficient have been evaluated; − a new accessory design has been developed to attach the electrodes to the new resonator design; − the technique and equipment of the workplace for balancing the mass of the resonator on the fourth harmonic of the unbalance to reduce its frequency mismatch have been developed. The technique was tested in the manufactured ample of CVG; − the technique of measuring the angles of non-orthogonality of the sensitive axis to its mounting surface has been developed and implemented in the experimental sample of CVG; − the use of CVG to improve the accuracy of armament stabilization was analyzed; − improved CVG standing wave control algorithm block diagram, which provides a fast start of the gyroscope when it is turned on at any temperature in the range of operating temperatures; − the techniques for temperature correction of quadrature and angular rate phases, multiparameter correction of CVG bias and scale factor have been developed and tested on experimental sample of CVG, which leads to an increase in the accuracy of measuring angular rate under temperature gradients; − the experimental results showed that the CVG with a metallic resonator is resistant to multiple shocks with amplitude 100 g and its bias is slightly dependent on the shock amplitude and does not exceed 5×10−3 deg/s. The bias sensitivity to vibration perturbations is 2.5×10−3 deg/s/g.
Диссертация посвящена научному обоснованию и разработке алгоритмов компенсации внутренних погрешностей и внешних возмущений в Кориолисового вибрационном гироскопе, а также совершенствованию его составных частей (резонатора, чувствительного элемента). Автором разработана методика и оборудование для рабочего места безэлектродного измерения динамических параметров металлического резонатора после его изготовления, разработана конструкция приспособления для приклеивания пьезоэлектродов к резонатору новой конструкции, методику и оборудование рабочего места для балансировки масс резонатора. Разработано и отработано на экспериментальном образце КВГ методики температурной коррекции фаз сигналов квадратуры и угловой скорости, многопараметрической коррекции дрейфа нуля и масштабного коэффициента, что приводит к увеличению точности измерения угловой скорости в условиях действия температурных градиентов.
Wu, Shiaw-Chian, and 吳孝謙. "On The Grasping Stability And Optimality Under External Perturbations." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/00037112206847808321.
淡江大學
資訊工程研究所
83
There are two kinds of grasping analyses in robotics researches: find the grasping force distribution among the fingers when given the contact points as well as find the points of contact when given the shape of the object. Each kind of problems is associated with optimality and stability analysis. In this paper, we start from analyzing the stability and optimality aspects of the grasping analysis under external perturbations and find a guantitative measurement that could evaluate the performance of different grasping configurations when grasping a given object. This property actually determines which grasping configuration is better hence give a solution to the two kinds of grasping analysis problems. We proof some rotation and displacement geometry model to derive a formula that describes the change of equilibrium grasping forces under the influence of external forces. Using this formula, we present a new concept, called the force mapping closure, that plays the central role of stability analysis. A minimum finger grasping force required for a non-slip contact under given external perturbation can be determined using the force mapping closure curve. Hence a method against any external perturbations is developed to construct a stable grasp. An optimal grasp can be guaranteed using the method we discussed if the external perturbations is not exceed some threshold value. In the paper, the planar cases and spatial cases is discussed, respectively, and a example of three-fingered planar grasp is provided.
馮睿璇. "An H∞ control design in robotic systems under parameter perturbation and external disturbance." Thesis, 1992. http://ndltd.ncl.edu.tw/handle/65136383991572087367.
Lin, Chih-Hao, and 林志豪. "Intrinsic Parameter Extraction and Stability Analysis on Quantum Dot Semiconductor Lasers with External Perturbations." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/49795423237126996307.
國立清華大學
光電工程研究所
102
In the dissertation, stability analysis and four-wave mixing (FWM) analysis are applied to investigate the characteristics of the relaxation oscillation of the quantum dot (QD) and the quantum well (QW) semiconductor lasers and their responses to the weak external perturbation, respectively. The FWM analysis can also be utilized to extract the intrinsic parameters of the semiconductor lasers, which apparently influence the dynamical behaviors. Through the modifications of strong external perturbations on the intrinsic parameters, the dynamical behaviors of the lasers can be investigated thoroughly. The linear stability analysis has been applied on the solitary and injection-locked lasers of QD and QW structures. By deriving the characteristic equations from the small internal fluctuations, the relaxation frequencies and the damping rate can be obtained. From the damping rates of the lasers with different bias currents, linewidth enhancement factors, injection strengths, and detuning frequencies, the QD lasers show better stability than the QW lasers. Moreover, the stability and excitability of the QD laser subject to optical feedback are also numerically discussed. To investigate the responses on small external perturbations in the FWM analysis, the rate equations of the solitary and injection-locked lasers of QD and QW structures are derived for the analytical solutions. Moreover, the FWM mixing analysis on the QD lasers subject to optical feedback is also derived. All the analytical models are carefully verified with the numerical simulations. FWM analysis has been applied on a QD laser to simultaneously obtain the linewidth enhancement factor and other intrinsic laser parameters. By fitting the experimentally obtained regenerative and amplitude modulation spectra at different detuning frequencies with the respective curves analytically calculated from the rate equations, parameters including the linewidth enhancement factor, the carrier decay rate in the dots, the differential gain, and the photon decay rate can be determined simultaneously under the same operating conditions. The sensitivity and accuracy of the parameter extracted by the FWM analysis are presented. Moreover, how each parameter alters the shapes of the regenerative and amplitude modulation spectra is also discussed. Moreover, a simplified rate equation model is utilized for the FWM analysis on QD lasers subject to optical injection. The regenerative and amplitude modulation spectra of the QD laser with different intrinsic laser parameters and external injection conditions are investigated. By curve fitting the regenerative and amplitude modulation spectra experimentally, the intrinsic laser parameters of a commercial single-mode QD laser under different injection conditions are extracted. The linewidth enhancement factor at different injection levels and detuning frequencies are shown, where a reduction of about 40% from its free-running value is demonstrated. By increasing the injection strength, the linewidth enhancement factor can be further reduced to minimize the chirp in optical communications. To comprehensively investigate the characteristics of QD laser subject to external perturbations, the model for the FWM analysis on the QD laser subject to optical feedback is also developed analytically. The modifications with different feedback conditions on the regenerative and amplitude modulation spectra are discussed. Also, how the regenerative and amplitude modulation spectra vary with each intrinsic parameter is discussed. Based on the theoretical prediction, we successfully extract the intrinsic parameters of the QD laser subject to optical feedback experimentally and the linewidth enhancement factor is found to increase with optical feedback.
Tokur, Dario Sinan. "Responses to External Perturbations in Selected Human Motor Tasks - A Systematic Review and Analysis." Phd thesis, 2019. https://tuprints.ulb.tu-darmstadt.de/9263/7/Dissertation_DarioTokur.pdf.