Submitted by Amanda Silva (amanda.osilva2@ufpe.br) on 2015-03-05T14:43:10Z No. of bitstreams: 2 DISSERTAÇÃO Amanda Maria da Silva.pdf: 2402414 bytes, checksum: 9a7a6f67f5b83f19d02e3f2e42814578 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-05T14:43:10Z (GMT). No. of bitstreams: 2 DISSERTAÇÃO Amanda Maria da Silva.pdf: 2402414 bytes, checksum: 9a7a6f67f5b83f19d02e3f2e42814578 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2014 / REUNI; CAPES / A fotogrametria usa basicamente a equação da colinearidade em que as rotações segundo os eixos cartesianos são dadas na forma conhecida como ângulos de Euler. No entanto, podem ocorrer combinações desses ângulos que torna a matriz de rotação numa situação instável e, assim, operações acabam incorretas ou até impossíveis, em algumas aplicações fotogramétricas. Este problema, chamado de gimbal lock (ou gimble lock), é comum em robótica, visão por computadores e aeronáutica, quando é necessário se definir a posição e orientação de uma câmara no espaço tridimensional, e tem sido resolvido com a substituição dos ângulos de Euler pelo uso dos quatérnios. Em fotogrametria podem ocorrer na fotogrametria terrestre ou a curta distância. O presente estudo tem por objetivo usar esta solução para resolver os possíveis problemas de orientações críticas em fotogrametria, em aplicações na resseção espacial e orientação relativa. Para tanto há a necessidade de estudar situações de instabilidades, matrizes de rotação com ângulos de Euler e quatérnios, aplicados para identificar situações críticas em várias operações da fotogrametria. Foram avaliadas situações simuladas e reais dos ângulos de Euler, substituindo pelos quatérnios na resseção espacial e orientação relativa. Pôde ser verificado que os modelos matemáticos da resseção espacial e orientação relativa funcionam bem para situações consideradas normais da fotogrametria. Os testes efetuados comprovaram que os quatérnios são mais robustos, de modo geral, permitem que possa ser calculada a resseção espacial com quatro pontos de forma direta e consegue calcular a resseção espacial, quando usados valores iniciais aproximados, com um menor de iterações, fato que pode fornecer resultados mais confiáveis. Os quatérnios permitem cálculos de resseção espacial e orientação relativa de fotografias em posições com ambiguidades de rotações e situações críticas de gimbal lock.

This thesis is about the modelling and control of three axis camera pan-roll-tilt unit (gimbal) which was meant to be attached to a multi rotor platform for aerial photography. The goal of the thesis was to develop a control structure for steering and active gyro stabilization of the gimbal, with aid from a mathematical model of the gimbal. Lagrange equations, together with kinematic equations and data from CAD drawings, were used to calculate a dynamics model of the gimbal. This model was set up as a Simulink simulation environment. Code for sensor reading and actuator control was written to the gimbal’s microprocessor and the code for the control structure in the gimbal was developed in parallel with a control structure in the simulation environment. The thesis resulted in a method for mathematical modelling of the gimbal and a control structure, for steering and active gyro stabilization of the gimbal, implemented in its control unit as well as in the simulation environment

International Telemetering Conference Proceedings / October 17-20, 1994 / Town & Country Hotel and Conference Center, San Diego, California / The XL-L Two-axis Pedestal is a novel adaptation of an existing design using a cross elevation over elevation axis configuration. This design affords full hemispherical coverage without gimbal lock (keyholes). In addition, the system provides continuous coverage without the necessity of rotary joints and sliprings. The design is ideally suited for shipboard systems, but is equally advantageous for any tracking mission where the target can approach a zenith gimbal lock or keyhole.

A gimbal is a pivoted device that decouples movements of a platform from its payload. The payload is a camera which must be stabilized to capture video without motion disturbances. A challenge with this type of gimbal is that a wide span of cameras with different sizes and weights can be used. The change of camera has significant effect on the dynamics of the gimbal and therefore the control system must be retuned. This tuning is inconvenient, especially for someone without knowledge of control engineering. This thesis reviews suitable methods to perform an automatic controller tuning directly on the gimbal's hardware.This tuning starts by exciting the system and then using data to estimate a model. This model is then used to control the gimbal, thus removing the need for manual tuning of the system. The foundation of this thesis is a physical model of the gimbal, derived through the Lagrange equation. The physical model has undetermined parameters such as inertias, centre of gravity and friction constants. System identification is used to determine these parameters. A problem discussed is how the system should be excited in order to achieve data with as much information as possible about the dynamics. This problem is approached by formulating an optimization problem that can be used find suitable trajectories. The identified model is then used to control the gimbal. Different methods for model based-control are discussed. By using a method called feedback linearisation all of the parameter-dependant dynamics of the gimbal can be compensated for. Apart from being independent of model parameters the new outer system is also decoupled and linear. A PID controller is used for feedback control of the outer system. The uncertainty of the feedback linearisation is analysed to find the effects of model errors.To assure robustness of the closed loop system a Lyapunov redesign controller is used to compensate for these model errors. Some experimental results are also presented. The quality of the estimated model is evaluated. Additionally, the reference tracking performance of the control system is tested and results reveal issues with the estimated model's performance.

I denna rapport beskrivs det arbete och resultat som utförts i kursen TDDD96- Kandidatprojekt i programvaruutveckling. Teamet som utvecklade projektet bestod av åtta civilingenjörsstudenter som studerar på data- eller mjukvaruutvecklingsprogrammet. Projektet gick ut på att utveckla en virtuell gimbal-kamera till Sjöräddningssällskapet som skulle hålla en låg latens, låg energiförbrukning och vara modulärt utbytbar. I utvecklingsprocessen användes en modifierad version av den agila arbetsmetoden Scrum. Det finns även individuella delrapporter som behandlar ämnen kopplade till projektet.

The purpose of this project was to construct a 2-axis stabilized model platform, as a proof of concept, intended to use for a cockpit base of a terrain vehicle or a combat boat. The stabilization of the platform in the roll and pitch axes is realized using a feedback control system that contains a proportional-integral-derivative (PID) controller, two DC motors driving the roll and pitch movements, and a 6-axis inertial measurement unit (IMU) measuring the roll and pitch angles. The project started with a study of various stabilized platforms and the theories behind them and a model of the system was created in SimuLink to simulate the system and design the controller. After the simulations where satisfactory a model platform of a scaled-down actual size was constructed. The platform’s frame was printed in a 3D printer. The control system for the platform has been implemented. The PID controller was implemented on the Arduino Mega 2560 development board, and it regulates the pitch and roll movements through two DC motors. The platform’s pitch and roll angles are measured by a 3-axis gyroscope in an IMU sensor (MPU-6050). The measurements are processed by a Kalman filter implemented on the Arduino board to reduce the noise. The Simulink simulation provided a functioning control system. However, the prototype of the implemented model platform does not work with god stability as expected. The reason for this result is mostly due to the unsuccessful construction of the platform frame and the bad choice of motors.

This diploma thesis provides a comprehensive proposal of stabilization mechanism for sensing and FPV camera for remote controlled propeller plane. Summarizes the current human knowledge milestones in the field and describes the current state of knowledge and the market situation. Taking into account all acquired knowledge the author then describes two different design proposals outlining its related processes, such as manufacturing, electronics installation and commissioning.

Sending a man in space is extremely dangerous. In order to continue the space exploration, robots have to be used. Designed properly, robots can handle any kind of operations in deep space. But in space there is no support such as an after-sale service. That is why their conception must be as perfect as possible to satisfy many tests. This is also the case of the ERA (European Robotic Arm). Its operations must be tested on the ground. But since forces acting at ground level are different than in space (e.g. gravity), the ERA must be in such position (the Iron Bird project) so that the target that it wants to reach must be brought by another robot. This other robot is called ERICA (Era Iron-bird CLU hArdware simulation). The goal of this project is to make the mechanical conception of the ERICA. The project was carried out in four parts. The first consisted in gathering information about the ERA in order to establish the requirements. The second was a pre-conception part. The third consists in explaining the research that had been made to choose the proper design of the ERICA. In the fourth part, the mechanical and electrical conception is presented. The ERICA is a gantry system where the payload is a gimbal holding a target. That way, the 6 degrees of freedoms of the ERA are achieved. The gantry system is provided by LinMotion and the motors by Maxon. The electronic parts are attached to the gantry at different places. A frame surrounds the working envelope so that the CLU (Camera and Lightning Units) can be fixed on it as well as protective plates against the CLU’s laser.

No description available.

Sverige är för tillfället operativa med Helikopter 16 - Black Hawk i Afghanistan. Uppgiften som löses i Afghanistan är främre och taktisk sjuktransport (MEDEVAC). Detta arbete handlar om hur befintliga VMS-system i helikoptrar kan kompletteras i syfte att möta ett föreliggande prickskyttehot vid lösande av främre MEDEVAC i ett insatsområde som miljömässigt liknar Afghanistan. I arbetet analyseras möjliga tekniker utifrån aspekter från ett konstruerat scenario där helikopterbesättningarnas uppgift, insatsmiljö samt hotbild beskrivs. Resultatet visar på att MEDEVAC-helikoptrar kan utrustas med sensor-gimbaler där olika sensorer kan kombineras, vilket möjliggör spaning i 360°. Detta bidrar till den militära nyttan då helikopterpersonalens lösande av uppgift effektiviseras, chansen till överlevnad ökar samtidigt som personal och patienter kan känna sig tryggare. / Currently, Sweden has operative Black Hawk helicopters in Afghanistan. The tasks they are solving in Afghanistan are forward and tactical Medical Evacuation (MEDEVAC). This work is about how existing Electronic Warfare Systems in helicopters can be supplemented in order to face a present sniper-threat during forward MEDEVAC in a conflict area which environmentally reminds of Afghanistan. In this work, a few possible techniques will be analyzed. This analyze will be based on aspects from a constructed scenario where the task to be solved, the conflict area, and the known threat is described. The result shows that MEDEVAC-helicopters can be equipped with operator-controlled sensor-gimbals where different electro-optical sensors can be combined. Gimbals allow reconnaissance in 360°. This contributes to the military utility since the main task can be solved by the helicopter personnel more effectively. Also, the probability of survival will probably increase and the personnel and wounded soldiers might feel more secure than before.