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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Modeling and Control of Risley Prism Beam Steering Including BLDC Motors

Gunnarsson, Oscar January 2016 (has links)
Saab AB Training & Simulation is specialized on military training, including laserbased training. To continue being the world leader in this area, a new generationof laser simulators needs to be developed. To simplify the development of thishighly complex system, this master thesis have resulted in a MATLAB/Simulinkmodel which simulates the electro-opto/mechanical system representing theirlaser based simulation platform. The focus of this master thesis has been to simulateand control the laser beam deflection. To be more precise, the motors usedto rotate the Risley-prisms deflecting the laser beam is modelled. With a goodmodel of the motors, a control system is applied steering the wedges to a referencerotation angle. The reference rotation angle is difficult to calculate though,since the deflection following several rotary wedges is severely nonlinear. Thereare many ways to calculate the rotation angles, but in this master thesis it will bedone by solving optimization problems in MATLAB. / Saab AB Training & Simulation är specialiserade på militär träning, bland annatbaserad på laser och för att fortsätta vara världsledande inom detta områdekrävs utveckling av en ny generation lasersimulatorer. För att underlätta utvecklingsarbetetav detta högst komplexa system, har i detta examensarbete en simulerbarmodell skapats i MATLAB/Simulink för att kunna simulera det elektroopto/mekaniska system som beskriver deras laserbaserade simulatorplattform.Fokus för detta examensarbete har varit att modellera avlänkningen. Mer ingåendeså modelleras de motorer som används för att rotera Risley-prisman så atten laserstråle uppnår önskad avlänkning. Med en bra modell av motorerna applicerasett reglersystem som styr de roterbara kilarna till referensposition. Referenspositionenär dock komplicerad att beräkna eftersom avlänkningen frånflera roterande kilar beter sig högst olinjärt. För att göra detta finns flera tillvägagångssätt,men i detta examensarbete kommer det att göras genom att lösaoptimeringsproblem i MATLAB.
2

Investigation of a New Method for Drone Dazzling Using Laser / Undersökning av en ny method för bländning av drönare med laser

Grundmark, Jens January 2021 (has links)
Drones have become more common, and are commercially available for consumers. Small drones can be used for unauthorized information gathering, or to cause disruptions. This has created a need for safe, effective countermeasures against drones. In this thesis, a method for countermeasures against drone imaging is investigated. The method is based on aiming and focusing a laser beam toward the camera of the drone. The retroreflection from the target is used as a feedback signal. Risley prisms were used to aim the beam, and an electrowetting lens was used to control the focus. Control algorithms based on the method called Stochastic Parallel Gradient Descent (SPGD), line searching and the Kalman filter are presented and evaluated. An experimental setup was used to track a moving target and dazzle a camera, demonstrating the validity of the method. Additionally, a simulation environment was used to estimate the potential performance of the control algorithms in a realistic scenario, under ideal circumstances.

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