Dissertations / Theses on the topic 'Optical sensing and motion control'
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Long, Fei. "Three-Dimensional Motion Control and Dynamic Force Sensing of a Magnetically Propelled Micro Particle Using a Hexapole Magnetic Actuator." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1452093964.
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Li, Li Wang Fei-Yue. "Advanced motion control and sensing for intelligent vehicles." New York : Springer, 2007. http://www.myilibrary.com?id=113830.
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Lin, Likun. "SDN-Enabled Dynamic Feedback Control and Sensing in Agile Optical Networks." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/613595.
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Fiber optic networks are no longer just pipelines for transporting data in the long haul backbone. Exponential growth in traffic in metro-regional areas has pushed higher capacity fiber toward the edge of the network, and highly dynamic patterns of heterogeneous traffic have emerged that are often bursty, severely stressing the historical "fat and dumb pipe" static optical network, which would need to be massively over-provisioned to deal with these loads. What is required is a more intelligent network with a span of control over the optical as well as electrical transport mechanisms which enables handling of service requests in a fast and efficient way that guarantees quality of service (QoS) while optimizing capacity efficiency. An "agile" optical network is a reconfigurable optical network comprised of high speed intelligent control system fed by real-time in situ network sensing. It provides fast response in the control and switching of optical signals in response to changing traffic demands and network conditions. This agile control of optical signals is enabled by pushing switching decisions downward in the network stack to the physical layer. Implementing such agility is challenging due to the response dynamics and interactions of signals in the physical layer. Control schemes must deal with issues such as dynamic power equalization, EDFA transients and cascaded noise effects, impairments due to self-phase modulation and dispersion, and channel-to-channel cross talk. If these issues are not properly predicted and mitigated, attempts at dynamic control can drive the optical network into an unstable state. In order to enable high speed actuation of signal modulators and switches, the network controller must be able to make decisions based on predictive models. In this thesis, we consider how to take advantage of Software Defined Networking (SDN) capabilities for network reconfiguration, combined with embedded models that access updates from deployed network monitoring sensors. In order to maintain signal quality while optimizing network resources, we find that it is essential to model and update estimates of the physical link impairments in real-time. In this thesis, we consider the key elements required to enable an agile optical network, with contributions as follows: *Control Framework: extended the SDN concept to include the optical transport network through extensions to the OpenFlow (OF) protocol. A unified SDN control plane is built to facilitate control and management capability across the electrical/packet-switched and optical/circuit-switched portions of the network seamlessly. The SDN control plane serves as a platform to abstract the resources of multilayer/multivendor networks. Through this platform, applications can dynamically request the network resources to meet their service requirements. *Use of In-situ Monitors: enabled real-time physical impairment sensing in the control plane using in-situ Optical Performance Monitoring (OPM) and bit error rate (BER) analyzers. OPM and BER values are used as quantitative indicators of the link status and are fed to the control plane through a high-speed data collection interface to form a closed-loop feedback system to enable adaptive resource allocation. *Predictive Network Model: used a network model embedded in the control layer to study the link status. The estimated results of network status is fed into the control decisions to precompute the network resources. The performance of the network model can be enhanced by the sensing results. *Real-Time Control Algorithms: investigated various dynamic resource allocation mechanisms supporting an agile optical network. Intelligent routing and wavelength switching for recovering from traffic impairments is achieved experimentally in the agile optical network within one second. A distance-adaptive spectrum allocation scheme to address transmission impairments caused by cascaded Wavelength Selective Switches (WSS) is proposed and evaluated for improving network spectral efficiency.
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Barsky, Michael Frederick. "Holographic sensing for control of flexible structures." Diss., This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-09162005-115002/.
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Frey, Bernhard F. "Differential optical motion and its functionality for the perception and control of heading." Thesis, University of Canterbury. Psychology, 1996. http://hdl.handle.net/10092/4514.
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The present program of investigation is concerned with the optical support for the perception and control of heading during constant-altitude approach to a stationary target. Of particular interest is the functional contribution of differential optical motion. The results of four experiments in which participants were given control over the direction of computer-simulated self-motion are reported. Results of Experiment 1 served to establish the potential performance range in terms of heading error. In addition, they provided a first indication of the functionality of motion parallax for the experimental task and demonstrated that target drift can be used for accurate approach. Results of Experiments 2 and 4 showed that successful target approach is not possible in the absence of both target drift and differential optical motion. Furthermore, they served to eliminate two alternative potentially functional types of information (rate of target expansion and apparent rotation of target), as well as provide a first indication of optimizing performance in the top end of the global optical flow velocity range commonly available during human bipedal self-motion. The latter result was replicated in Experiment 3. Experiments 3 and 4 were specifically designed to evaluate the functionality of simple motion parallax (SMP) and differential motion parallax (DMP). A separation ratio (σ) indexing the separation of two objects in depth was able to account for (a) performance improvements with decreasing distance to the target, and (b) most of the performance differences among all simulated environments. With the effect of σ accounted for, the addition of DMP information to events that already carried SMP information did not affect performance. The rate of change in horizontal optical separation between at least two discontinuities is identified as the most likely candidate for the optical foundation of the perception and control of heading during target approach. In conclusion, suggestions for the development of formal descriptions of this variable are made.
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Merrell, Paul Clark. "Structure from Motion Using Optical Flow Probability Distributions." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd764.pdf.
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Lewis, Jeremy. "A steady state tip control strategy for long reach robots." Thesis, Middlesex University, 1996. http://eprints.mdx.ac.uk/13569/.
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The work presented in this thesis describes the development of a novel strategy for the steady state tip position control of a single link flexible robot arm. Control is based upon a master/slave relationship. Arm trajectory is defined by through 'master' positioning head which moves a laser through a programmed path. Tip position is detected by an optical system which produces an error signal proportional to the displacement of the tip from the demand laser spot position. The error signal and its derivative form inputs to the arm 'slave' controller so enabling direct tip control with simultaneous correction for arm bending. Trajectory definition is not model-based as it is defined optically through movement of the positioning head alone. A critical investigation of vacuum tube and solid state sensing methods is undertaken leading to the development of a photodiode quadrant detector beam tracking system. The effect of varying the incident light parameters on the beam tracker performance are examined from which the optimum illumination characteristics are determined. Operational testing of the system on a dual-axis prototype robot using the purpose-built beam tracker has shown that successful steady state tip control can be achieved through a PD based slave controller. Errors of less than 0.05 mm and settling times of 0.2 s are obtained. These results compare favourably with those for the model-based tip position correction strategies where tracking errors of ± 0.6 mm are recorded.
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Zhou, Jia Qi. "Simplified Analysis of IMU Sensor Corruptions on Existing Pendulation Control System For Ship-Mounted Crane." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/36123.
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Ship-mounted boom cranes play an important role in the ship-to-ship offshore cargo transport process. In recent years, there has been significant need to increase stability of the payload during the cargo transport process for both safety and efficiency reasons. However, the stability of the payload during the transport process directly correlates to the ship's pitch and roll motion that in turn relates to the current particular sea-state.
In this study, we analyze an existing Pendulation Control System (PCS) developed by Sandia National Laboratories that reduces the payload's pendulation movement during transport. This system measures the ship motion through a complex inertial navigation system using an IMU and dual GPS receivers. In trying to simplify the analysis of the IMU sensor, we simulate new control solutions based solely on an IMU-only ship motion measurement system using both position- and velocity-based controllers. This study shows that an optional bandpass filter in the new control solution can reject a bias that appears in the estimated accelerometer data at the expense of higher sensitivity for the control. This study also shows that the velocity-based solution provides comparable if not better results than the position-based solution. Both methods are sensitive to the difference between the ship motion period and the center frequency of its bandpass filter. Lastly, it is shown that the bias of an accelerometer is not a large source of payload disturbance as compared to the scale factor error.Master of Science
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Mikov, Nikolay. "A distributive approach to tactile sensing for application to human movement." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/11608.
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This thesis investigates on clinical applicability of a novel sensing technology in the areas of postural steadiness and stroke assessment. The mechanically simple Distributive Tactile Sensing approach is applied to extract motion information from flexible surfaces to identify parameters and disorders of human movement in real time. The thesis reports on the design, implementation and testing of smart platform devices which are developed for discrimination applications through the use of linear and non-linear data interpretation techniques and neural networks for pattern recognition. In the thesis mathematical models of elastic plates, based on finite element and finite difference methods, are developed and described. The models are used to identify constructive parameters of sensing devices by investigating sensitivity and accuracy of Distributive Tactile Sensing surfaces. Two experimental devices have been constructed for the investigation. These are a sensing floor platform for standing applications and a sensing chair for sitting applications. Using a linear approach, the sensing floor platform is developed to detect centre of pressure, an important parameter widely used in the assessment of postural steadiness. It is demonstrated that the locus of centre of pressure can be determined with an average deviation of 1.05mm from that of a commercialised force platform in a balance application test conducted with five healthy volunteers. This amounts to 0.4% of the sensor range. The sensing chair used neural networks for pattern recognition, to identify the level of motor impairment in people with stroke through performing functional reaching task while sitting. The clinical studies with six real stroke survivors have shown the robustness of the sensing technique to deal with a range of possible motion in the reaching task investigated. The work of this thesis demonstrates that the novel Distributive Tactile Sensing approach is suited to clinical and home applications as screening and rehabilitation systems. Mechanical simplicity is a merit of the approach and has potential to lead to versatile low-cost units.
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Jain, Advait. "Mobile manipulation in unstructured environments with haptic sensing and compliant joints." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45788.
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We make two main contributions in this thesis. First, we present our approach to robot manipulation, which emphasizes the benefits of making contact with the world across all the surfaces of a manipulator with whole-arm tactile sensing and compliant actuation at the joints. In contrast, many current approaches to mobile manipulation assume most contact is a failure of the system, restrict contact to only occur at well modeled end effectors, and use stiff, precise control to avoid contact.
We develop a controller that enables robots with whole-arm tactile sensing and compliant actuation at the joints to reach to locations in high clutter while regulating contact forces. We assume
that low contact forces are benign and our controller does not place any penalty on contact forces below a threshold. Our controller only requires haptic sensing, handles multiple contacts across the surface of the manipulator, and does not need an explicit model of the environment prior to contact. It uses model predictive control with a time horizon of length one, and a linear quasi-static mechanical model that it constructs at each time step.
We show that our controller enables both a real and simulated robots to reach goal locations in high clutter with low contact forces. While doing so, the robots bend, compress, slide, and pivot around objects. To enable experiments on real robots, we also developed an inexpensive, flexible, and stretchable tactile sensor and covered large surfaces of two robot arms with these sensors. With an informal experiment, we show that our controller and sensor have the potential to enable robots to manipulate in close proximity to, and in contact with humans while keeping the contact forces low.
Second, we present an approach to give robots common sense about everyday forces in the form of probabilistic data-driven object-centric models of haptic interactions. These models can be shared by different robots for improved manipulation performance. We use pulling open doors, an important task for service robots, as an example to demonstrate our approach.
Specifically, we capture and model the statistics of forces while pulling open doors and drawers. Using a portable custom force and motion capture system, we create a database of forces as human operators pull open doors and drawers in six homes and one office. We then build data-driven
models of the expected forces while opening a mechanism, given knowledge of either its class (e.g, refrigerator) or the mechanism identity (e.g, a particular cabinet in Advait's kitchen). We demonstrate that these models can enable robots to detect anomalous conditions such as a locked door, or collisions between the door and the environment faster and with lower excess force applied to the door compared to methods that do not use a database of forces.
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Alfeeli, Bassam. "Miniature gas sensing device based on near-infrared spectroscopy." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/35911.
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The identification and quantification of atoms, molecules, or ions concentrations in gaseous samples are in great demand for medical, environmental, industrial, law enforcement and national security applications. These applications require in situ, high-resolution, non-destructive, sensitive, miniature, inexpensive, rapid detection, remotely accessed, real time and continuously operating chemical sensing devices. The aim of this work is to design a miniature optical sensing device that is capable of detecting and measuring chemical species, compatible with being integrated into a large variety of monitoring systems, and durable enough to be used under extreme conditions.
The miniature optical sensor has been realized by employing technologies from the optical communication industry and spectroscopic methods and techniques. Fused silica capillary tubing along with standard communication optical fibers have been utilized to make miniature gas sensor based on near-infrared spectroscopy for acetylene gas detection.
In this work, the basic principles of infrared spectroscopy are reviewed. Also, the principle of operation, fabrication, testing, and analysis of the proposed sensor are discussed in details.Master of Science
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Swanepoel, Petrus Johannes. "Omnidirectional image sensing for automated guided vehicle." Thesis, Bloemfontein : Central University of Technology, Free State, 2009. http://hdl.handle.net/11462/39.
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Thesis (M. Tech.) -- Central University of Technology, Free State, 2009Automated Guided Vehicles (AGVs) have many different design specifications, although they all have certain design features in common, for instance they are designed to follow predetermined paths, and they need to be aware of their surroundings and changes to their surroundings. They are designed to house sensors for navigation and obstacle avoidance. In this study an AGV platform was developed by modifying an electric wheelchair. A serial port interface was developed between a computer and the control unit of the electric wheelchair, which enables the computer to control the movements of the platform. Different sensors were investigated to determine which would be best suited and most effective to avoid collisions. The sensors chosen were mounted on the AGV and a programme was developed to enable the sensors to assist in avoiding obstacles. An imaging device as an additional sensor system for the AGV was investigated. The image produced by a camera and dome mirror was processed into a panoramic image representing an entire 360o view of the AGV‟s surroundings. The reason for this part of the research was to enable the user to make corrections to the AGV‟s path if it became stuck along the track it was following. The entire system was also made completely wireless to improve the flexibility of the AGV‟s applications.
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Bafumba, Liseli Joël. "Design and control of a piezoelectric positioning systems, with high resolution, multiple degrees of freedom and an embedded measurement by self-sensing." Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCD017.
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De nos jours, les systèmes intègrent de plus en plus de fonctionnalités dans des volumes de plus en plus petits grâce aux microcomposants intégrés. L'assemblage de ces microcomposants nécessite des systèmes de manipulation précis et reproductibles. Un nombre considérable de recherches ont été menées afin de mettre au point des actionneurs et des microrobots capables d'effectuer des tâches de positionnement ou de manipulation avec des précisions microniques voire submicroniques. Les technologies piézoélectriques jouent un rôle fondamental dans les applications de positionnement à résolution nanométrique ou même inférieure. Ces matériaux permettent la conception et le développement de systèmes de positionnement avec résolution et bande passante élevées. Cependant, des effets non linéaires tels que l'hystérésis et la dérive lente affectent la précision de la position des systèmes à base piézoélectrique s'ils ne sont pas contrôlés. Souvent, des capteurs de position sont montés sur ces systèmes pour permettre un contrôle en boucle fermée et l'élimination des effets d'hystérésis et de dérive lente. Néanmoins, l'intégration de capteurs permettant un asservissement robuste et de qualité pose des problèmes spécifiques aux microrobots. Cela est particulièrement vrai lorsque le nombre de degrés de liberté augmente. En effet, les capteurs de position qui jouissent d'une bonne résolution et précision sont généralement très volumineux et coûteux. Les solutions alternatives à l’intégration de capteurs de position externes peuvent être regroupées en deux catégories: soit par contrôle en boucle ouverte, également appelé schémas de contrôle prédictifs, soit par des techniques basées sur le contrôle par auto-détection (Self-Sensing Actuation - SSA), c’est-à-dire un contrôle en boucle fermée utilisant l'actionneur piézoélectrique comme son propre capteur.Dans cette thèse, l'objectif est de concevoir et de contrôler un système de positionnement basé sur la technologie piézoélectrique avec une méthode de mesure intégrée par SSA et ayant plusieurs degrés de liberté. À cette fin, les deux classes de SSA, à savoir le SSA basé sur l’effet direct piézoélectrique et le SSA basé sur la modification des propriétés électriques de l'actionneur piézoélectrique (PEA), sont étudiées en profondeur afin de déterminer celle qui convient le mieux au contrôle de la force et de la position dans les actionneurs piézoélectriques caractérisés par le fluage et non-linéarités d'hystérésis et consacrés à des opérations précises. De plus, cette étude présente un modèle constitutif et une technique d’identification de paramètres améliorés, qui prend en compte l’effet de couplage électromécanique et les non linéarités sur les propriétés du matériau piézoélectrique (constantes élastiques et diélectriques).Une nouvelle technique d'évaluation en temps réel des propriétés électriques du PEA est développée. Cette évaluation est basée sur la mesure de l’amplitude du courant de détection résultant de l’application d’une tension d’entrée haute fréquence de faible amplitude superposée à la tension d’entrée de commande qui actionne le PEA. Ensuite, un estimateur qui utilise le courant de détection pour estimer la position du PEA est conçu. Enfin, une plate-forme microrobotique pour le positionnement planaire à haute résolution avec la mesure intégrée par SSA développée est présentéeCurrently, systems integrate more and more functionalities into smaller volumes thanks to embedded micro-components. The assembly of those components requires precise and repeatable systems of manipulation. Substantial amounts of research have been carried out for developing actuators and microrobots to perform positioning or manipulation with micron- or even submicron accuracies. Piezoelectric technologies play a fundamental role in positioning applications with nanoscale or even lower resolution. These materials make possible the design and development of positioning systems with high resolution and bandwidth. However, nonlinear effects such as hysteresis and creep affect the position accuracy of piezoelectric-based systems if not controlled. Often, position sensors are mounted to these systems to permit a feedback control and the elimination of the hysteresis and creep effects. Nonetheless, the integration of sensors to enable quality and robust servo control poses specific problems for microrobots. This is especially true when the number of degrees of freedom (DOF) increases. Precision position sensors are usually very bulky and expensive. Alternative solutions to the integration of external position sensors can be grouped into two categories: either by open-loop control, also called feedforward control schemes or by Self-Sensing Actuation (SSA) control-based techniques, that is, a feedback control that uses the piezoelectric actuator as its own sensor.In this thesis, the objective is to design and control a piezoelectric-based positioning system with an embedded measurement by SSA method and having several degrees of freedom. To this end, the two classes of SSA, namely SSA based on the piezoelectric direct effect and the SSA based on the change of electrical properties of the piezoelectric actuator (PEAs), are studied in depth to determine the more adequate for force and position control in piezoelectric actuators typified by creep and hysteresis nonlinearities and devoted to precise operations. Additionally, from this study, an improved constitutive model and parameter identification technique are presented which includes the electromechanical coupling effect on the piezoelectric material properties (elastic and dielectric constants).A novel technique for real-time evaluation of the PEA's electrical properties is developed. This evaluation is based on the measurement of the amplitude of the detection current that results from the application of high-frequency low amplitude input voltage that is superimposed to the control input voltage which actuates the PEA. Then an estimator that uses the detection current to estimate the PEA's position is designed. Finally, a microrobotics platform for planar positioning with high resolution and the developed embedded measurement by SSA is presented
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Acosta, Reche Manuel [Verfasser], Valentin [Akademischer Betreuer] Ivanov, Yuri A. W. [Gutachter] Shardt, and Daniel [Gutachter] Watzening. "Vehicle dynamics virtual sensing and advanced motion control for highly skilled autonomous vehicles / Manuel Acosta Reche ; Gutachter: Yuri A.W. Shardt, Daniel Watzening ; Betreuer: Valentin Ivanov." Ilmenau : TU Ilmenau, 2020. http://d-nb.info/1204827176/34.
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Huang, Yanan. "Active Control and Adaptive Estimation of an Optically Trapped Probing System." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1250617605.
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Liu, Zhen. "Reconstruction and Control of Tip Position and Dynamic Sensing of Interaction Force for Micro-Cantilever to Enable High Speed and High Resolution Dynamic Atomic Force Microscopy." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483629656167247.
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Zhang, Zhipeng. "MAGNETIC TWEEZERS: ACTUATION, MEASUREMENT, AND CONTROL AT NANOMETER SCALE." Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1243885884.
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Authié, Colas. "Contrôle visuel du déplacement en trajectoire courbe : approche sensorimotrice du rôle structurant du flux optique." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX22085.
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L'objectif principal de cette thèse est de mettre en évidence le rôle de la direction et du mouvement de la tête et des yeux dans la perception et le contrôle de trajectoires courbes, en référence aux propriétés des flux optiques générés par notre déplacement dans un environnement stable. Nous utilisons deux méthodes expérimentales : une approche comportementale sur simulateur de conduite et une approche psychophysique permettant d'évaluer les capacités d'observateurs humains à percevoir la direction du mouvement propre. Ces méthodes combinées visent à mettre en évidence les effets comportementaux d'une perception active de la direction du mouvement propre. L'introduction dresse l'état de la recherche sur les informations disponibles et les stratégies perceptives impliquées dans la prise de virage en conduite automobile. Ainsi, l'accent est à la fois mis sur le rôle du point de corde (dans le cas étudié d'un déplacement sur une route délimitée) et plus généralement sur le rôle du flux optique (description de la transformation apparente de l'environnement visuel lors du déplacement), soulignant notre capacité à interpréter spatialement le mouvement, mais aussi le caractère indissociable de la motricité et de la perception. Nous abordons ensuite le rôle des mouvements combinés des yeux et de la tête, dans une perspective fonctionnelle du contrôle du mouvement.Dans un premier chapitre expérimental, nous analysons les mouvements d'orientation de la tête lors de la prise de virage en conduite simulée. Nous montrons que les mouvements de la tête sont indépendants de la manipulation du volant et qu'ils participent activement à l'orientation du regard vers le point de corde. Dans un second chapitre expérimental, nous nous attachons à décrire les mouvements combinés des yeux et de la tête, en lien avec la géométrie de l'environnement routier. Dans une troisième partie, nous analysons plus finement le comportement du regard en lien avec la direction du point de corde et la vitesse locale du flux optique. Nous montrons à la fois que le point de corde correspond à un minimum local de vitesse optique et que la composante globale du flux optique induit un nystagmus optocinétique systématique. Enfin, lors d'une quatrième étude psychophysique, nous nous attachons à décrire finement l'effet de la variation de la direction du regard sur la discrimination de la direction du mouvement propre. Nous montrons que les seuils de discrimination de trajectoire sont minimaux lorsque le regard est orienté vers une zone de vitesse de flux minimal. Nous proposons finalement un modèle de détection de la trajectoire, basé sur une fraction de Weber des vitesses de flux fovéales, qui prédit très précisément les seuils expérimentaux. Les stratégies observées d'orientation du regard (combinaison des mouvements des yeux et de la tête) vers le point de corde sont compatibles avec une sélection optimale de l'information présente dans le flux optiqueThe main purpose of this dissertation is to determine the role of the direction and movement of the eyes and the head in the perception and control of self-motion in curved trajectories, with respect to the properties of the optical flows generated in a stable environment. To do so, we used two experimental methods: a psychophysical approach which allows to assess human observers' ability to perceive the direction of self-motion; and a behavior-based approach on a driving simulator. The two methods combined should help to highlight active perception of self-motion.The introduction reviews the current knowledge of perceptuo-motor strategies during curve driving. In this context, we put a stress on both (1.) the particular role of the tangent point -- in the driving situation on a delimited road, and on the role of the optic flow in general (apparent transformation of the optic array during self-motion), emphasizing the capability of humans to spatially interpret the movement; and (2.) on the duality between movement and perception. We then address the role of head-and-eye combined movements, in a functional perspective of the control of self-motion. In a first experimental section, we analyze the oriented movements of the head in simulated curve driving. We demonstrate that head movements are independent from the handling of the steering wheel, and that they actively participate in the gaze orientation toward the tangent point.In a second experimental section, we set out to describe the combined movements of head and eyes, with respect to the geometry of the road environment. In a third section, we analyze in more details gaze behavior as a function of the tangent point direction and of the local speed of optical flow. We demonstrate that the tangent point corresponds to a local minimum of optic flow speed and that the global component of the optic flow induces a systematic optokinetic nystagmus. In a fourth section involving a psychophysical study, we scrutinize the effect of varying gaze direction on the discrimination of the direction of self-motion. We show that the trajectory discrimination thresholds are minimal when the gaze is oriented toward an area of minimum flow speed. We finally propose a model of trajectory change detection, relying on a Weber fraction of foveal flow speeds, predicting the experimental thresholds very precisely. The gaze orientation strategies we have observed (combination of head and eye movements) toward the tangent point are compatible with this model and with the hypothesis of an active an optimal selection of the information contained in the optical flow
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Sohr, Martin. "Zabezpečovací systém pro rodinný dům." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219383.
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Family house, security system, wireless communication, IQRF, RSA, central control unit, SPI, I2C, glass break sensors, motion sensors, magnetic contact sensors, graphic displey, LCD displey, microcontroler, SIM900, 24FJ256GB106, EA DOGM106, eDIPTFT43-A.
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Kuo, Chia-Heng, and 郭家恆. "Development of Motion Control System Applied on Multi-axis motion-sensing Platform." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/7wk9qp.
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碩士國立中山大學
機械與機電工程學系研究所
107
In this thesis, Visual Studio C # is used as software development tool to establish a PC-based motion control system with commercially available motion control card. This is employed as the master controller for crank-links multi-axis motion-sensing platform. Servo motors, drivers, and reducers are integrated as the driving source in this crank-links platform system. Ethernet Control Automation Technology (EtherCAT) serial-transmission mechanism is utilized as the servo communication of these servo modules. To meet the operability of the user’s demand, the specific application programming interface (API) commands for motion control system are used to build the human machine interface. There are several testing functions established in this HMI for users including the system initialization, motion status feedback, security warning, etc. Inertial Measurement Unit (MPU-6050) is utilized for monitoring the slope of motion-sensing platform. With the evaluation of platform mechanical inertia and the driving modules, the optimized proportional-integral (PI) controlling parameters are calculated by simulating software. To enhance the response of the system, Cascade rule is imported to design PI controlling parameters. Compared with Auto-tuning, the step response simulation and experiments of velocity loop and position loop are tested in time domain. The response and motor bandwidth are improved effectively with parameters designed by Cascade rule. In the motion platform testing part, with the optimized parameters and using of Kalman filter algorithm, the platform angle measurement error is reduced 30% while rotating. At the final, test the control command and platform motions. The angular error of pitch motion is 0.596°; roll motion is 1.321°, and distance error of heave motion is 1.664 cm.
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Teh, Chun-Fu, and 葉俊甫. "USE KINECT SENSING ROBOT FOOT TRAJECTORY TRACHING MOTION CONTROL." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/39976741357301129659.
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碩士大同大學
電機工程學系(所)
103
In this thesis, Kinect sensor is used to build a robust 3D leg gesture recognition system in legs action tracking such that the legs of the robot in the remote site can duplicate the leg actions that of the human. As compared to actions of the entire human body, the legs action behave more complex articulations and are more easily affected by kinematics modeling errors. It is thus a very attractive and challenging problem to transfer the leg gestures of the human after recognition to that of the robot. The robust leg gesture recognition is proposed to handle the kinematics and inverse kinematics from the legs' ankle trajectory obtained from the Kinect sensor. According to the leg inverse kinematics, the distance metric between human and the Kinect sensor is used to measure the dissimilarity between human and robot by legs shapes and ankle trajectory. As it only matches the ankle tip parts while not the whole leg, it can better distinguish the leg gestures of slight differences by inverse kinematics. The experiments demonstrate that the proposed leg gesture recognition system is accurate (a 95\% mean accuracy on a challenging 5-gesture dataset), distortions and orientation or scale changes, and can work in uncontrolled environments in cluttered backgrounds.
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Wang, Chien-Wen, and 王建文. "Interactive Motion Sensing Game to Improve Postural Control Ability." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/37230569889246915772.
Full textAbstract:
碩士義守大學
資訊工程學系
102
Postural control is to maintain or control the body to achieve the positioning and stability. Impaired postural control may cause disadvantageous effects on one’s functional ability and raise their risk of falling. In this study, we apply the Kinect sensor, the Wii-Fit balance board and a seesaw board to build postural-suprapostural dual task training environment, allowing subjects to play batting ball game for improving their ability of postural control. Fifteen healthy adults (age: 24 ± 3 years) without any history of neurological disease were recruited in this study. All participants were instructed to perform the postural -suprapostural dual task training by playing six rounds of batting ball game on a seesaw board. Subjects were tested on a Wii-Fit balanced board while performing two-leg stance, one-leg stance, and airpillow stance for sixty seconds before and after the postural-suprapostural dual task training. Root mean square of center of pressure in the medial-lateral plane was computed to assess postural control. Our results indicated the postural-suprapostural dual task batting ball training game facilitate postural control improvements (p < 0.01).
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Chang, Ting-yu, and 張廷宇. "Smart Optical Automotive Rain-Sensing Wiper Control System." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/64315070946404719564.
Full textAbstract:
碩士明志科技大學
機電工程研究所
95
ABSTRACT The main function of the wiper for vehicle is to remove the rain/water and particles on the windshield in order to provide a clear viewing for the driver behind. However, the driver turns on the wiper based on the fuzzy-human being of the amount of rain/water on the shield. It is much more dangerous act when the car is just moving on the road. The wiper system of car is thus an active device of safety. The purpose of this thesis is to design the wiper control system, this system with the infrared light source LED, sensor and the light pipe of special design, the light shooting to inner light pipe and distribute evenly over the windshield. Most of diffusible light already over the way of critical angle, total internal reflection phenomenon arose in the windshield. The infrared light of total internal reflection sends back a sensor with a certain value. If the surface of the windshield contains raindrops, the result of the total internal reflection will reduce, and it can makes the responsive-value of sensor to reduce. In addition, this research builds sensing circuit and the control circuit of the wiper motor, 2.2 KHz is the fixed vibration rate of light source that can be detected through detecting circuit optical modulation function, and matching with a bandpass filter to suppress excepted light noise, and then deliver the signal to the micro-controller, and use micro-controller as a judgment unit of the signal-processing to make the noise reduce and raise judgment accuracy. To judge the weather sledding and precipitation is according to responsive-value, and it send a signal to circuit-controlling to drive wiper motor. By the experiment, it is better that the threshold value is set 0.025. It can make the timely reaction of the wiper cohere with drive safety. This system can suppress excepted light noise by optical modulation method was verified after experiment. Finally by the on-line experiment can auto-adjust immediately wiper speed according to precipitation; delay time is including: moderate rain(4.1016 mms/hr) 0.008s, heavy rain(29.297 mms/hr) 0.004s, small fog( 0.1054 mms/hr) 5.8s, heavy mist( 0.5859 mms/hr) 4.3s. So this system can respond the environment variety to make the Wiper Control System start and adjust the speed by itself.
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Seebacher, J. Paul. "Motion control using optical flow of sparse image features." Thesis, 2015. https://hdl.handle.net/2144/15191.
Full textAbstract:
Reactive motion planning and local navigation of robots remains a significant challenge in the motion control of robotic vehicles. This thesis presents new results on vision guided navigation using optical flow. By detecting key image features, calculating optical flow and leveraging time-to-transit (tau) as a feedback signal, control architectures can steer a vehicle so as to avoid obstacles while simultaneously using them as navigation beacons.
Averaging and balancing tau over multiple image features successfully guides a vehicle along a corridor while avoiding looming objects in the periphery. In addition, the averaging strategy deemphasizes noise associated with rotationally induced flow fields, mitigating risks of positive feedback akin to the Larsen effect.
A recently developed, biologically inspired, binary-key point description algorithm, FReaK, offers process speed-ups that make vision-based feedback signals achievable. A Parrot ARDrone2 has proven to be a reliable platform for testing the architecture and has demonstrated the control law's effectiveness in using time-to-transit calculations for real-time navigation.
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Yeh, Shen-kai, and 葉勝凱. "Motion-Cueing Improvement on Simulator Using Intelligent Control and Sensing Technique." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/03953108966516916649.
Full textAbstract:
碩士逢甲大學
自動控制工程所
95
The purpose of this research is to improve the motion-cueing of the simulator. The purpose of this research is to improve the motion-cueing of the simulator. After we obtained the movement information with vision based system, we can achieve precisely closed-loop feedback servo control. By using single visual information, 3D positions of three feature points on the movable platform are obtained in order to determine the attitude of the motion platform in real-time. This constructed simulator can satisfy the training requirements of pilot-in-the-loop simulation, which is the focus of this research. Classical and fuzzy control washout algorithm will be proposed in this study to achieve the requirement of high motion-cueing fidelity within the limited platform working space. As we know, all the parameters of classical washout algorithm must be generated by hand-tuning process, but the parameters can be tuned automatically by using fuzzy rule. On the other hand, in order to achieve the real-time tracking control of the attitude in the motion-cueing platform, we design an auto-focusing technique of the vision machine and apply the dynamic image processing technique to measure the attitude of platform in real-time. In this research, we transform the images of feature points on the upper platform into the world coordinate system by using image coordinate transformation with plane projection transfer method, and then calculate the corresponding platform attitude. Close loop feedback control will be realized by sending the attitude of platform back to the computer.
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汪奎仲. "Human Gesture Based Physical Agent Motion Control Using Body Sensing Technology." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/28669069442916020720.
Full textAbstract:
碩士逢甲大學
資訊工程學系
102
We proposes a motion-sensing technology based physical agent control interface. Through a Kinect skeleton tracking function used for recording users’ body motion data, users can easily translate human body motions into the commands/programs for triggering the corresponding robot motions. Such that an Application Programming Interface (API) for robot control/manipulation is therefore built. Such an API is helpful to programmers who involve robots’ motions in their programs in eliminating the burdens of low level and trivial coding of robot mechanical controls. Additionally, for the users who will write codes for performing continuous robot motions, this paper also proposes a graphic authoring tool for editing robot motion. Moreover, by combining the built-in speech recognition function of Kinect, programmers may easily design the desired robot motion.
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CHIA, NAI-CHIEH, and 賈乃杰. "Human Gesture Based Multiple Physical Agent Motion Control Using Body Sensing Technology." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/7649b5.
Full textAbstract:
碩士逢甲大學
資訊電機工程碩士在職學位學程
107
This paper proposes a system that simplifies the authoring of robot movements for users, capturing the user's gestures and movements in a somatosensory manner. And then the system converts them into robot movement commands using vectors and kinematics, and enhances the capturing of multiple human body movements through multiple Kinect devices. Identifying and capturing gestures and processes, and adding some of multi-agent interaction parameters, such as time space, to allow multiple users to use the body as a controller to control the actions of multiple agents simultaneously. Finally, by enhancing RDSL into Multi-Robot-control Domain Specific Language (MRDSL), the action authoring mechanism can be used in other robot application systems as a complete robot development environment.
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Yen, Chih-Hui, and 顏誌輝. "Applying Motion Sensing Control to Virtual Reality: Example on Tainan Chihkan Tower Navigation." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/774mxz.
Full textAbstract:
碩士國立臺中科技大學
多媒體設計系碩士班
100
The innovation of motion sensing interaction technology is more creative in nowadays. Game development had been using motion sensing interaction to become a new multimedia interaction spotlight. Therefore, our study is exploring the effect of control methods using users body pose to operate interface on multimedia. By using Microsoft’s new product “Kinect” as an input sensing device to identify body pose changing through image recognition. The virtual reality digital content combined with human-computer interaction and used motion sensing interaction of directing manipulation applying to virtual reality navigation. Most virtual reality digital navigation are using keyboard and mouse as input device in general. Our study featured that user do not wear any devices. Integration visual-based detection technology with Tainan Chihkan Tower navigation is our purpose. To build different from traditional way controls virtual reality by giving new virtual reality navigation interaction. User experience and user interactive feedback make much more effective. After integrating our system, we execute user questionnaire to know what body or gesture is better to navigate. Then, we define two control ways and adjust navigation details. After adjusting, we do the second user questionnaire into three parts, motion sensing, user satisfaction, and SUS evaluation. The results show that all of mean satisfactions are more than average value. That indicates our interaction navigation is accepted for users, most of these users considered our research is innovating and entertaining as well.
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Gutiérrez-Medina, Braulio. "Quantum transport and control of atomic motion with light." Thesis, 2004. http://hdl.handle.net/2152/1198.
Full text
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Gutiérrez-Medina, Braulio Raizen Mark George. "Quantum transport and control of atomic motion with light." 2004. http://wwwlib.umi.com/cr/utexas/fullcit?p3142733.
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Chahal, Anthony M. "Optical end point sensing and digital control of a scanning tunneling microscope." Thesis, 1993. http://hdl.handle.net/2429/1292.
Full textAbstract:
The problem addressed in this thesis is that of digitally controlling a Scanning Tunneling Microscope and implementing end point sensing to close the control loop for accurate X-Y positioning of the microscope tip. This first part entails modifying a microscope with an analog controller so that it may be interfaced to a DSP system running on a personal computer. The second part is designing and incorporating an optical end point sensor into the head of the microscope to improve absolute position control of the tip in the scanning plane by overcoming hysteresis and creep in the piezoelectric scanning tube actuator. The sensor would also improve the repeatability of imaging and facilitate random access positioning of the tip to allow for more sophisticated scanning trajectories. The digital controller was successfully implemented. Images of sputtered gold obtained with the new controller were of comparable quality to those obtained using a microscope under analog control. A single axis version of the sensor was developed which was used independently of the microscope to measure the hysteresis and creep that were present in the piezoelectric actuator. The sensor had a resolution of 8.5 nm, but was not completely integrated into the digital control and imaging system.
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Fu, Pin-Yen, and 傅彬硯. "Design of an Automated Optical Inspection System Motion Control Based on Industrial Personal Computer." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/05183708653793423972.
Full textAbstract:
碩士崑山科技大學
電機工程研究所
102
The purpose of the dissertation is to develop a motion control for an automated optical inspection (AOI) system based on an industrial personal computer (IPC). The IPC is used as AOI system host control via a variety of interface card to control related equipment, which achieve the goals set by the detection system. The AOI system has the complete and continuous vision image capture function, which can detect the glass defect. In this study, Borland C + + is used as an integrated development environment. The C language is used as a system architecture design and development to construct an AOI motion control. The control objects contain the linear servo motor, line scan camera, light sources produce machine, motion control card, video capture card and A / D, D / A servo control card, which constitutes the AOI system. The experimental results show that the proposed AOI system has been constructed properly.
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"Analytical Control Grid Registration for Efficient Application of Optical Flow." Doctoral diss., 2013. http://hdl.handle.net/2286/R.I.17831.
Full textAbstract:
abstract: Image resolution limits the extent to which zooming enhances clarity, restricts the size digital photographs can be printed at, and, in the context of medical images, can prevent a diagnosis. Interpolation is the supplementing of known data with estimated values based on a function or model involving some or all of the known samples. The selection of the contributing data points and the specifics of how they are used to define the interpolated values influences how effectively the interpolation algorithm is able to estimate the underlying, continuous signal. The main contributions of this dissertation are three fold: 1) Reframing edge-directed interpolation of a single image as an intensity-based registration problem. 2) Providing an analytical framework for intensity-based registration using control grid constraints. 3) Quantitative assessment of the new, single-image enlargement algorithm based on analytical intensity-based registration. In addition to single image resizing, the new methods and analytical approaches were extended to address a wide range of applications including volumetric (multi-slice) image interpolation, video deinterlacing, motion detection, and atmospheric distortion correction. Overall, the new approaches generate results that more accurately reflect the underlying signals than less computationally demanding approaches and with lower processing requirements and fewer restrictions than methods with comparable accuracy.Dissertation/Thesis
Ph.D. Bioengineering 2013
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Förster, Leonid [Verfasser]. "Microwave control of atomic motion in a spin dependent optical lattice / vorgelegt von Leonid Förster." 2010. http://d-nb.info/100992625X/34.
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Si-ChenPan and 潘思辰. "Design and Control of an Active Stage for Suppressing Motion Induced Vibration in Optical Inspection Systems." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/2q57z7.
Full textAbstract:
碩士國立成功大學
機械工程學系
107
Along with the development of industrial technologies in various manufacturing and metrology applications, fast positioning and vibration suppression play important roles in virtually all tasks requiring high speed of maneuvers with sufficient motion accuracy. One typical example is on the optical inspection system, it performs numerous product defect inspections by fast moving to the desired inspection locations and take images for defect evaluation. Due to the inherent structural compliance and the inertial force generated during fast movement, residual vibrations will be inevitable for the point-to-point movement and this implies that additional settling time would be required for avoiding blurred images. Obviously, mounting a controllable stage on machine can effectively reduce residual vibration, thereby improving inspection efficiency. Therefore, this work develops an active stage with rubber bearings and flexible structure equipping with a CCD camera, designs the corresponding controller, and verifying the vibration suppression capability of the active stage system under the action of the linear motor. In terms of stage design, the four sets of rubber-bonded aluminum blocks form rubber bearing which provide stiffness of the stage, and a flexible beam is mounted on stage for imitating the camera-support structure of the real machine. The model parameters are identified by dynamic testing and the mathematical model of the active stage is obtained. In terms of controller design, this work adopts both loop transmission (L.T.) shaping and input shaping methods. Through the L.T. method, two schemes called A and B, have been developed successively to handle the positioning and vibration suppression. On the issue of stage positioning, the overshoot and settling time of the A scheme are 9.2% and 0.16s. Once it cooperating with input shaping scheme, the corresponding performance can be further reduced to 7.1% and 0.09s. On the vibration suppression issue, the residual vibration and settling time of the A scheme are originally 154.1% and 1.3s and are improved to 31.0% and 0.60s with input shaping schemes. Therefore, the shaping-control integration can effectively improve the system controlled performance in comparison with the results from control only. Meanwhile, in order to further improve the vibration suppression in feedback control, we also develop the B scheme and it successfully reduces residual vibration and settling time to 30.4% and 0.25s. Finally, essential AOI inspection experiments are carried. Based on captured image, the active stage employ above schemes can indeed reduce the blur level to achieve a faster inspection. This work successfully confirmed that the active stage control system can effectively reduce residual vibration during optical inspection, thereby improving inspection efficiency.
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Babakeshizadeh, Vahid. "Biologically-inspired Motion Control for Kinematic Redundancy Resolution and Self-sensing Exploitation for Energy Conservation in Electromagnetic Devices." Thesis, 2014. http://hdl.handle.net/10012/8123.
Full textAbstract:
This thesis investigates particular topics in advanced motion control of two distinct
mechanical systems: human-like motion control of redundant robot manipulators
and advanced sensing and control for energy-efficient operation of electromagnetic
devices.
Control of robot manipulators for human-like motions has been one of challenging
topics in robot control for over half a century. The first part of this thesis
considers methods that exploits robot manipulators??? degrees of freedom for such
purposes. Jacobian transpose control law is investigated as one of the well-known
controllers and sufficient conditions for its universal convergence are derived by
using concepts of ???stability on a manifold??? and ???transferability to a sub-manifold???.
Firstly, a modification on this method is proposed to enhance the rectilinear trajectory
of the robot end-effector. Secondly, an abridged Jacobian controller is
proposed that exploits passive control of joints to reduce the attended degrees of
freedom of the system. Finally, the application of minimally-attended controller
for human-like motion is introduced.
Electromagnetic (EM) access control systems are one of growing electronic systems
which are used in applications where conventional mechanical locks may not
guarantee the expected safety of the peripheral doors of buildings. In the second
part of this thesis, an intelligent EM unit is introduced which recruits the selfsensing
capability of the original EM block for detection purposes. The proposed
EM device optimizes its energy consumption through a control strategy which
regulates the supply to the system upon detection of any eminent disturbance.
Therefore, it draws a very small current when the full power is not needed. The
performance of the proposed control strategy was evaluated based on a standard
safety requirement for EM locking mechanisms. For a particular EM model, the
proposed method is verified to realize a 75% reduction in the power consumption.
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Liu, Hsing-Fu, and 劉星甫. "THE STUDY OF SURFACE PLASMON RESONANCE OPTICAL FIBER- 400 ?慆 SENSORS BASED ON TiO2 COATING FOR SENSITIVITY IMPROVEMENT AND WAVELENGTH CONTROL IN SENSING." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/96671229685193272392.
Full textAbstract:
碩士大同大學
光電工程研究所
98
Surface Plasmon Resonance（SPR）technique has been widely used in the chemical and biological properties and molecular interaction detection. Conventional SPR sensors have the advantages of high sensitivity, real-time dynamic measurement capability, and in the biological sensing without the use of labels. Besides, fiber itself has small size, low cost, and high compatibility with the requirement of SPR sensing and applications. In this paper, the SPR fiber sensors we proposed enable us to combine the advantages of optical fiber and multilayer SPR sensing structure to develop a new type of SPR fiber sensor, for detecting the small refractive index change of the medium or monitoring the thickness during the nano thin film deposition. The multi-mode fiber we proposed in this paper with the core diameter of 400 ?慆 is prepared as a sensor platform, for the SPR measurement after the multi-layer TiO2/Au films were coated on the side-polished surface. We adjust the thickness of TiO2 film that coated on the Au thin film surface to shift the guided light SPR absorption from the ordinary region of the wavelength of 600-700 nm to the region of 1300-1550 nm that normally uses for the optical fiber communication. The SPR fiber sensors possessing SiO2/Au multi-layer structure can easily be integrated with existing optical fiber communication network as a smart fiber sensing system. Besides, the multi-layer structure we proposed can also enhance the SPR sensing sensitivity as well as increase the dynamic range of the SPR dip wavelength measurement. The experiment results show that the optimal sensitivity of the refractive index detection for the DI water and NaCl solution exhibits the ability as low as 3.47 ?~10-6 a.u., with the thickness of the TiO2 layer of 40 nm coated on the Au film surface.
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Roberts, Lyle Edward. "Internally Sensed Optical Phased Arrays." Phd thesis, 2016. http://hdl.handle.net/1885/110523.
Full textAbstract:
The performance of existing ground-based space debris laser
ranging systems can be improved by directing more light onto
space debris by coherently combining multiple lasers using an
optical phased array (OPA). If the power delivered to target is
sufficiently high then these systems may also provide the
capability to remotely manoeuvre space debris via photon
radiation pressure and/or ablation. By stabilising the relative
output phase of multiple lasers, OPAs form a coherent optical
wave-front in the far field. Since the phase of each laser can be
controlled independently, they also have the ability to
dynamically manipulate the distribution of optical power in the
far field, potentially enabling them to compensate for
atmospheric turbulence. This beam-forming functionality, combined
with their inherent scalability and high power handling
capabilities make OPAs a promising technology for future space
debris laser ranging and manoeuvring systems.
In this thesis, we describe the iterative development of a
high-power compatible internally sensed OPA, which---in contrast
to externally sensed OPAs that sense the output phase of each
laser externally using free-space optics---relies on the small
fraction of light that is reflected back into the fibre at the
output of the OPA to stabilise its relative output phase. This
allows internally sensed OPAs to be implemented entirely within
fibre without any dependence on free-space optics at the output,
offering potential advantages over externally sensed techniques
when operating in the presence of shock and vibration.
A proof-of-concept experiment demonstrated the viability of
internal sensing, but also highlighted a number of weaknesses
that would affect its utility, specifically in supporting high
optical powers greater than 100s of mW. An improved high-power
compatible internally sensed OPA was designed to overcome these
restrictions by isolating sensitive optical components from high
optical powers using asymmetric fibre couplers. This concept was
initially demonstrated experimentally using slave lasers offset
phase-locked to a single master laser, and then again using fibre
amplifiers in a master oscillator power amplifier configuration.
The experimental demonstration of the fibre amplifier compatible
OPA stabilised the relative output phase of three commercial 15 W
fibre amplifiers, demonstrating a root-mean-squared output phase
stability of $\lambda/194$, and the ability to steer the beam at
up to 10 kHz.
The internally sensed OPA presented here requires the
simultaneous measurement, and control of the phase of each
emitter in the OPA. This is accomplished using digitally enhanced
heterodyne interferometry and digitally implemented phasemeters,
both of which rely heavily on high-speed digital signal
processing resources provided by field-programmable gate-arrays.
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Vorster, Willem Adriaan. "Assessment and analysis of wildfires with the aid of Remote Sensing and GIS." Diss., 2013. http://hdl.handle.net/10500/14433.
Full textAbstract:
Wildfires destroy large tracts of veld and forest land every year in South Africa. These fires can be devastating, resulting in loss of human lives, the destruction of property and the loss of income, for example the forest fire in the Sabie district in Mpumalanga in 2007 which destroyed about 7% of South Africa’s forested areas. There are frequently legal disputes with respect to the origin of wildfires, the extent of the fire and the land cover destroyed by the fires.
The forensic capabilities of remote sensing in detecting and analysing post-wildfire characteristics have become an important contribution towards solving such legal disputes and in understanding wildfire characteristics. These post fire products can be used as evidence in court cases. Most of the time those court cases came up a few years after the fire event. By then, little or no evidence can be found on the terrain where the fire was. Remote sensing archives provide a reliable source of data that can be used to analyse these events after these long intervals.
The objective of this project is to highlight the methods used to generate these post-wildfire analysis products.Environmental Sciences
M. Sc. (Environmental Science)
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Prates, Pedro Alexandre de Sousa. "A Cooperative Approach for Autonomous Landing of UAVs." Master's thesis, 2018. http://hdl.handle.net/10362/51002.
Full textAbstract:
This dissertation presents a cooperative approach for the autonomous landing of MRVTOL
UAVs (Multi Rotor-Vertical Take-off and Landing Unmanned Aerial Vehicles). Most
standard UAV autonomous landing systems take an approach, where the UAV detects
a pre-set pattern on the landing zone, establishes relative positions and uses them to
perform the landing. These methods present some drawbacks such as all of the processing
being performed by the UAV itself, requiring high computational power from it. An
additional problem arises from the fact most of these methods are only reliable when the
UAV is already at relatively low altitudes since the pattern’s features have to be clearly
visible from the UAV’s camera. The method presented throughout this dissertation relies
on an RGB camera, placed in the landing zone pointing upwards towards the sky. Due to
the fact, the sky is a fairly stagnant and uniform environment the unique motion patterns
the UAV displays can be singled out and analysed using Background Subtraction and
Optical Flow techniques. A terrestrial or surface robotic system can then analyse the
images in real-time and relay commands to the UAV.
The result is a model-free method, i.e independent of the UAV’s morphological aspect
or pre-determined patterns, capable of aiding the UAV during the landing manoeuvre.
The approach is reliable enough to be used as a stand-alone method, or be used along
traditional methods achieving a more robust system. Experimental results obtained from
a dataset encompassing 23 diverse videos showed the ability of the computer vision
algorithm to perform the detection of the UAV in 93,44% of the 44557 evaluated frames
with a tracking error of 6.6%. A high-level control system that employs the concept of
an approach zone to the helipad was also developed. Within the zone every possible
three-dimensional position corresponds to a velocity command for the UAV, with a given
orientation and magnitude. The control system was tested in a simulated environment
and it proved to be effective in performing the landing of the UAV within 13 cm from the
goal.
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Eloff, Corné. "Spatial technology as a tool to analyse and combat crime." Thesis, 2006. http://hdl.handle.net/10500/1193.
Full textAbstract:
This study explores the utilisation of spatial technologies as a tool to analyse and combat crime. The study deals specifically with remote sensing and its potential for being integrated with geographical information systems (GIS). The integrated spatial approach resulted in the understanding of land use class behaviour over time and its relationship to specific crime incidents per police precinct area.
The incorporation of spatial technologies to test criminological theories in practice, such as the ecological theories of criminology, provides the science with strategic value. It proves the value of combining multi-disciplinary scientific fields to create a more advanced platform to understand land use behaviour and its relationship to crime.
Crime in South Africa is a serious concern and it impacts negatively on so many lives. The fear of crime, the loss of life, the socio-economic impact of crime, etc. create the impression that the battle against crime has been lost. The limited knowledge base within the law enforcement agencies, limited logistical resources and low retention rate of critical staff all contribute to making the reduction of crime more difficult to achieve.
A practical procedure of using remote sensing technology integrated with geographical information systems (GIS), overlaid with geo-coded crime data to provide a spatial technological basis to analyse and combat crime, is illustrated by a practical study of the Tshwane municipality area. The methodology applied in this study required multi-skilled resources incorporating GIS and the understanding of crime to integrate the diverse scientific fields into a consolidated process that can contribute to the combating of crime in general.
The existence of informal settlement areas in South Africa stresses the socio-economic problems that need to be addressed as there is a clear correlation of land use data with serious crime incidents in these areas. The fact that no formal cadastre exists for these areas, combined with a great diversity in densification and growth of the periphery, makes analysis very difficult without remote sensing imagery. Revisits over time to assess changes in these areas in order to adapt policing strategies will create an improved information layer for responding to crime. Final computerised maps generated from remote sensing and GIS layers are not the only information that can be used to prevent and combat crime. An important recipe for ultimately successfully managing and controlling crime in South Africa is to strategically combine training of the law enforcement agencies in the use of spatial information with police science.
The researcher concludes with the hope that this study will contribute to the improved utilisation of spatial technology to analyse and combat crime in South Africa. The ultimate vision is the expansion of the science of criminology by adding an advanced spatial technology module to its curriculum.Criminology
D.Litt. et Phil. (Criminology)