Dissertations / Theses on the topic 'Platform stabilization'

This Master thesis describes the development and modification of already existing assembler software for the DRUi 360. The DRUi is a controller unit for stabilization tasks mostly used in the military industry. The DRUi controls the stabilization platform which has the purpose to simulate a moving vehicle. The aim with this platform is for internal development of new hardware and software, evaluate new ideas and components for stabilization systems. The platform is also an internal education system for the engineers. The DRUi receives the input reference signal from the Ground Profile Generator which is a graphical interface running on a PC were the user has the ability to create or send already recorded road signals from a moving vehicle to the driver unit. In this case the DRUi. The main used software’s for this project are Code Composer Studio for programming the DRUi software and LabVIEW which is a graphical programming language used to program the Ground Profile Generator. A theoretical study of motion control is performed together with getting familiar of al the equipment. The new software for the DRUi is adapted and implemented. Filter design for the regulator unit and necessary measurements on the test stand are presented together with the results of the production run of the stabilization platform. The stabilization platform is not fully running when this thesis ended. When the production test was performed disturbances appeared in the system. The reasons for these disturbances are not yet discovered. Al safety routines needed for running the platform secure and prevent system damage are implemented to the system software.

During the uniform locomotion of legged robots with compliant legs, the body of the robot exhibits quasi-periodic oscillations that have a disturbing eect on dierent onboard sensors. Of particular interest is the camera sensor which suers from image degradation in the form of motion-blur as a result of this camera motion. The eect of angular disturbances on the camera are pronounced due to the perspective projection property of the camera. The thesis focuses on the particular problem of legged robots exhibiting angular body motions and attempts to analyze and overcome the resulting disturbances on a camera carrying platform (head). Although the full problem is in 3D with three independent axes of rotation, a planar analysis provides signicant insight into the problem and is the approach taken in the thesis. A carefully modeled planar version of an actual camera platform with realistic mechanical and actuator selections is presented. Passive (ltering) and active (controller) approaches are discussed to compensate/cancel motion generated disturbances. We consider and comparatively evaluate PID and LQR based active control. Since PID has the limitation of controlling only one output, PID-PID control is considered to iv control two states of the model. Due to its state-space formulation and the capability of controlling an arbitrary number of states, LQR is considered. In addition to standard reference signals, Gyroscope measured disturbance signals are collected from the actual robot platform to analyze the bandwidth and test the performance of the controllers. Inverted pendulum control performance is evaluated both on a Matlab-Simulink as well as a precise electro-mechanical test setup. Since construction of the planar head test setup is in progress, tests are conducted on simulation.

In this thesis work construction of the angular acceleration signal of a 2-DOF gimbal platform and use of this signal for improving the stabilization performance is aimed. This topic can be divided into two subtopics, first being the construction of angular acceleration and the second being the use of this information in a way to improve system performance. Both problems should be tackled in order to get satisfactory results. The most important output of this work is defined as the demonstration of the improvements obtained both theoretically and on experimental setup. Although the system to be studied is a two axis gimbal platform, the results obtained can be applied to other servo control problems. It is possible to define different performance criteria for a servo control problem and different techniques will be addressed with different control objectives. For this thesis work, the performance criterion is defined as the stabilization performance of the platform. As a result, disturbance rejection characteristics of the controller emerges as the main topic and methods for rejecting these disturbances such as the friction torques and externally applied moments are focused on throughout the studies. As expected, remarkable improvement is achieved as a result of the use of acceleration feedback.

Recording a video sequence with a camera during movement often produces blurred results. This is mainly due to motion blur which is caused by rapid movement of objects in the scene or the camera during recording. By correcting for changes in the orientation of the camera, caused by e.g. uneven terrain, it is possible to minimize the motion blur and thus, produce a stabilized video. In order to do this, data gathered from a gyroscope and the camera itself can be used to measure the orientation of the camera. The raw data needs to be processed, synchronized and filtered to produce a robust estimate of the orientation. This estimate can then be used as input to some automatic control system in order to correct for changes in the orientation This thesis focuses on examining the possibility of such a stabilization. The actual stabilization is left for future work. An evaluation of the hardware as well as the implemented methods are done with emphasis on speed, which is crucial in real time computing.
En videosekvens som spelas in under rörelse blir suddig. Detta beror främst på rörelseoskärpa i bildrutorna orsakade av snabb rörelse av objekt i scenen eller av kameran själv. Genom att kompensera för ändringar i kamerans orientering, orsakade av t.ex. ojämn terräng, är det möjligt att minimera rörelseoskärpan och på så sätt stabilisera videon. För att åstadkomma detta används data från ett gyroskop och kameran i sig för att skatta kamerans orientering. Den insamlade datan behandlas, synkroniseras och filtreras för att få en robust skattning av orienteringen. Denna orientering kan sedan användas som insignal till ett reglersystem för att kompensera för ändringar i kamerans orientering. Denna avhandling undersöker möjligheten för en sådan stabilisering. Den faktiska stabiliseringen lämnas till framtida arbete. Hårdvaran och de implementerade metoderna utvärderas med fokus på beräkningshastighet, som är kritiskt inom realtidssystem.

Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2017.
Small and micro unmanned aerial vehicles (UAV) are rapidly becoming viable platforms for surveillance, aerial photography, firefighting and even package delivery. While these UAVs that are of the rotorcraft type require little to no extra infrastructure for their deployment, they are typically saddled with short ranges and endurance, thus placing a restriction on their usage. On the other hand, UAVs that are of fixed wing type generally have longer range and endurance but often require a runway for take-off and landing which places a restriction on their usage. This project focuses on the development of a vertical take-off and landing (VTOL) UAV demonstrator suitable for integration on a small or mini flying wing UAV (a fixed wing UAV) to counteract the take-off and landing limitations of fixed wing type UAVs. This thesis first presents a propulsion characterisation experiment designed to determine the thrust and moment properties of a select set of propulsion system components. The results of the characterisation experiment identified that the propulsion set of a Turnigy C6374 – 200 brushless out runner electric motor driving a 22 x 10 inch three bladed propeller will provide approximately 79N (8kg) of thrust at 80% throttle (4250rpm). Therefore, two of these propulsion set would satisfy the platform requirement of 12kg maximum take-off mass (MTOM). The result of the abovementioned experiment, together with the VTOL platform requirements were then used as considerations for the selection of the suitable VTOL method and consequently the design of the propulsion configuration. Following a comparison of VTOL methods, the tilt-rotor is identified as the most suitable VTOL method and a variable speed twin prop concept as the optimal propulsion configuration.

Gyroscopic stabilization can be used to maintain an otherwise unstable body in an upright position. Devices equipped with gyroscopes can balance upon a small area or point without falling over when the gyroscopic stabilizing force is greater than a rotational force or moment from an out-of-balance load that causes the device to tip. A new concept for a gyroscopically stabilized platform has been proposed in the form of a schematic diagram. The proposed system comprises of four interconnected gyroscopes that react to the tipping of an inherently unstable external body. The purpose of this research is to evolve a design for, and establish the feasibility of building the proposed stable platform using available materials and technology. If feasible, the gyroscopically stabilized platform will be made at the most practical and economic size. Louis Brennan developed a 37 tonne monorail that was maintained in the upright position with two 3 tonne counter rotating gyroscopes. The Brennan monorail is analysed to better understand the behaviour of a similar coupled gyroscopic stabilization system. The reactions between the components that maintain the monorail in the stable position are studied and comparisons are made between the proposed stable platform and the Brennan system. A mathematical analysis of the proposed system is presented. The equations of motion for the system are derived using the Lagrangian Formalism. The characteristic equation of the system is then determined and from this a set of stability conditions imposed on the design of the physical parameters of the stable platform. The general solutions to the equations of motion are then derived. Expressions that model the behaviour of two of the variables that describe the motion of the stable platform are determined. A systematic approach is adopted for establishing a new concept for the proposed system. Testing of the initial stable platform prototype (Prototype A) showed the system did not behave as intended. The platform was optimised further and this resulted in a second prototype, Prototype B. Prototype B exhibiting the desired oscillatory motion about the vertical of the platform. Predictions made using the mathematical model are compared with empirical results. The mathematical model was found to be an accurate method for predicting the response of the stable platform.

This thesis describes the development of a robotic platform for evaluation of gaze stabilization algorithms built for the Sensorimotor Systems Laboratory at the University of British Columbia. The primary focus of the work was to measure the performance of a biomimetic vestibulo-ocular reflex controller for gaze stabilization using cerebellar feedback. A flexible robotic system was designed and built in order to run reproducible test sequences at high speeds featuring three dimensional linear movement and rotation around the vertical axis. On top of the robot head a 1 DOF camera head can be independently controlled by a stabilization algorithm implemented in Simulink. Vestibular input is provided by a 3-axis accelerometer and a 3-axis gyroscope. The video feed from the camera head is fed into a workstation computer running a custom image processing program which evaluates both the absolute and relative movement of the images in the sequence. The absolute angles of tracked regions in the image are continuously returned, as well as the movement of the image sequence across the sensor in full 3 DOF camera rotation. Due to dynamic downsampling and noise suppression algorithms very good performance was reached, enabling retinal slip estimation at 720 degrees per second. Two different controllers were implemented, one adaptive open loop controller similar to Dean et al.’s work[12] and one reference implementation using closed loop control and optimal linear estimation of reference angles. A sequence of tests were run in order to evaluate the performance of the two algorithms. The adaptive controller was shown to offer superior performance, dramatically reducing the movement of the image for all test sequences, while also offering better performance as it was tuned over time.

This project explores the possibility to stabilize a hand held serving-tray using a micro-controller, two servomotors and an inertial measurement unit (IMU). It is heavily focused on control theory, specifically using a PID controller. Stabilization of an object using a PID controller have many applications such as drones, camera stabilizers and flight simulators. The report covers the theory necessary to construct a self stabilizing platform and describes involving components in the prototype and how they cooperate. With the gyroscopes and accelerometers involved in the IMU it is possible to determine orientation and rotation of the tray. The construction enables rotation about the x-axis (roll) and y-axis (pitch) but not the z-axis (yaw). The readings from the gyroscopes and the accelerometers are combined and filtered through a complementary filter to estimate the rotations. The servomotors compensate disturbance in keeping the platform horizontal through PID regulation. The PID constants are tuned through tilting the platform at a specific angle and plotting the step response in MATLAB.
Detta projekt utforskar möjligheten att stabilisera en handhållen serveringsbricka med hjälp av en mikrokontroller, två servomotorer och en tröghetssensor (IMU). Projektet lägger mycket fokus på reglerteknik, specifikt att använda en PID-regulator. Stabilisering genom PID-reglering är användbart i många olika produkter, exempelvis drönare, kamerastabiliserare och flygsimulatorer. Rapporten täcker relevant teori för att konstruera en självstabiliserande plattform och beskriver ingående komponenter i prototypen samt hur de samverkar. Med gyroskopen och accelerometrarna som finns i IMU:n är det möjligt att uppskatta position och rotation för ett objekt. Konstruktionen tillåter rotation kring x-axeln (roll) och y-axeln (pitch) men inte zaxeln (yaw). Mätningarna från gyroskopen och accelerometrarna kombineras och filtreras med hjälp av ett s.k. complementary filter för att uppskatta rotationen av objektet. Servomotorerna används i sin tur till att hålla plattan horisontell genom att kompensera störningar från omgivningen. Detta görs genom PID-reglering. Konstanterna i PID-regulatorn är framtagna genom tester där plattformen lutas ett bestämt antal grader och stegsvaret plottas i MATLAB.

This report handles the preliminary design of a control system that includes both attitude control and boost control functionality for sounding rockets. This is done to reduce the weight and volume for the control system.

A sounding rocket is a small rocket compared to a satellite launcher. It is used to launch payloads into suborbital trajectories. The payload consists of scientific experiments, for example micro-gravity experiments and astronomic observations. The boost guidance system controls the sounding rocket during the launch phase. This is done to minimize the impact dispersion. The attitude control system controls the payload during the experiment phase.

The system that is developed in this report is based on the DS19 boost guidance system from Saab Ericsson Space AB. The new system is designed by extending DS19 with software and hardware. The new system is therefore named DS19+. Hardware wise a study of the mechanical and electrical interfaces and also of the system budgets for gas, mass and power for the system are done to determine the feasibility for the combined system.

Further a preliminary design of the control software is done. The design has been implemented as pseudo code in MATLAB for testing and simulations. A simulation model for the sounding rocket andits surroundings during the experiment phase has also been designed and implemented in MATLAB. The tests and simulations that have been performed show that the code is suitable for implementation in the real system.

In future human spaceflight missions, with prolonged exposure to microgravity, resistive and aerobic exercises will be countermeasures for bone loss, muscle loss, and decreased aerobic capacity. Two of the exercises of interest are squats and rowing. The cyclic forces produced during these exercises are at relatively low frequencies which are likely to excite structural resonances of space vehicles. Vibration Isolation Systems (VIS) are being designed to be paired with future exploration exercise devices in order to prevent these cyclic exercise forces from impacting the space vehicle. The VIS may be configured such that a platform supports the human and exercise device. There is limited knowledge about the interaction between a human exercising and a dynamic platform. This research sought to fill part of the knowledge gap and study how the force inputs to the platform change as well as how exercise form was affected. For this research, a system which can produce dynamic responses similar to those of a prospective VIS platform was used. This system is the Computer Assisted Rehabilitation Environment (CAREN) (Motekforce Link, Amsterdam, Netherlands). Simplified sinusoidal responses were implemented in a single degree of freedom, vertical (heave) motion, and also in multi-degree of freedom, heave and pitch motion. Human subject testing was conducted using four subjects with exercise experience. The subjects completed squats and rows, while standing, in both static (platform not moving) and dynamic (with platform moving) conditions. Subjects aimed to synchronize with platform motion, at the appropriate phase. Kinetic and kinematic data were collected via force plate measurements and motion capture, respectively. Testing was completed with several predetermined frequencies for platform motion, but also at each subject’s baseline frequency, which was the measured, comfortable exercise rate for the subject. Data were processed and arranged in a presentable format. Results showed attenuation of the vertical component of forces between the comparable frequency static and dynamic platform conditions, as expected, for most subjects in the squat exercise. This was seen only in the heave with pitch condition during rows for most subjects. Results also showed increasing amplitude of forces as frequency increased, which was also expected. Knee angle range of motion was well maintained between static and dynamic conditions. These results suggest that conditions desirable for both VIS and exercise are possible. Further testing and extended analysis at additional amplitudes, frequencies, and degrees of freedom are of interest and warrant further study. This work contributed knowledge and data regarding the forces involved and human kinematics produced while exercising with platform motion. These data can further be used as inputs and requirements for VIS design work, VIS and human biomechanical modeling, and exercise countermeasure development. This work achieved the objectives of establishing an appropriate test environment and developing platform dynamics in which human-VIS interaction could be studied. It also acted as a proof-of-concept for future testing which can be conducted to answer new questions relating to dynamic platform motion effects on human activity.

This diploma thesis deals with design and realization of control board with controlling program for stabilization platform application. Thesis is splitted in to six parts. In first part of thesis are summarized required parameters and properties of proposed system together with explanation of necessary theoretical basics. In second part of thesis is made analysis of sensors which are designated for sensing necessary magnitudes. Namely then magnetometer, accelerometer, gyroscope. For every sensor is there made analysis of influence caused by parasitic effects. In conclusion of second part is made choice of concrete sensors by choosing sensory module. Third part deals with conception of mechanical solution. Fourth part of thesis deals with design and construction of control board and also with description of circuit functional blocks. This is followed with fifth part which describing program equipment of board with setting up sensory module. In last part of thesis are described conclusions of testing.

This bachelor thesis is about the design and construction of a self-stabilizing platform. The purpose of this system is to balance objects placed upon the platform by keeping the platform level regardless of how the mechanism itself is rotated. Its uses include stabilization of sensors, cameras and vehicle cockpits. The prototype was constructed using 3D printing and basic machining. It uses two DC motors, an inertial measurement unit, an Arduino Uno microcontroller and a motor driver. The inertial measurement unit acts as an accelerometer and gyroscope, it measures the change in position and angle relative to its starting position. The controller algorithm processes the sensor signal and calculates an appropriate output signal. This output signal regulates the two DC motors in such a way that compensates for any angle changes in the platform. This project is based on, and is the continuation of the work by J. Larsson, titled ”Gimbal stabilizer for cockpit bases of terrain vehicle or combat boat: A proof of concept”. The task is to develop it to a functioning physical prototype and implement a control system which is fast, responsive and precise. The controller tuning process involved a trial and error approach, using binary search between parameters that give a performance that is too slow and a performance that is too fast and unstable. A satisfactory performance was achieved and the platform could effectively stabilize objects that weigh 400 grams at its center, 200 grams at its edges and 100 grams at its corners. This takes 100 milliseconds on average. Besides bearing loads, the platform could also compensate for sudden forced angle changes and any tilting of the mechanism the platform is attached to.
Det här kandidatexamensarbetet handlar om konstruktionen och framtagningen av en prototyp för en självstabiliserande plattform med ändamålet att hålla ett objekt horisontellt stabil. Det innebär att oberoende av hur mekanismen vrids eller rör sig kommer plattformen alltid vara parallell med marken. Appliceringsområden för plattformen kan vara att stabilisera kameror och sensorer, samt att hålla förarkabinen i en båt horisontellt stabil oavsett hur vattnet runtomkring rör sig. Prototypen består av en 3D-printad mekanism med två likströmsmotorer, en tröghetssensor, Arduino och motordrivare. Tröghetssensorn fungerar som en accelerometer och gyroskop - den avläser hur mycket plattformen ändrar sitt läge och vinkel relativt de ursprungliga. Data från tröghetssensorn bearbetas i en Arduino Uno-mikrokontroller med hjälp av reglerteknik, där en så kallad PID-regulator beräknar utsignal beroende på insignal. Arduinon skickar sedan utsignalen till motordrivaren som reglerar likströmsmotorerna för att kompensera för eventuella vinkeländringar. Detta projekt ¨ar ett utvecklingsarbete av ett tidigare masterexamensarbete av J. Larsson, med titeln ’ ’Gimbal stabilizer for cockpit bases of terrain vehicle or combat boat: A proof of concept”. Målet är att gå från ett koncept till en praktisk och verklighetsbaserad prototyp, samt att designa en regulator med god precision, stabilitet och responstid. För att bestämma hur regulatoralgoritmen ska fungera användes binärsökning för att hitta vilka P, I och D-värden PID-regulatorn ska ha. Det innebär att man ständigt tar ett medelvärde av en för långsam regulator och en som är för snabb och aggressiv tills önskad prestanda uppnås. Den slutgiltiga prestandan ansågs vara tillräcklig och plattformen kunde effektivt stabilisera 400 gram i mitten på den, 200 gram på dess sidor och 100 gram på dess hörn på ungefär 100 millisekunder. Vidare kunde den kompensera för plötsliga påtvingade vinkeländringar och för lutning hos mekanismen som den sitter fast i.

The vestibuloocular reflex can be manually elicited by tilting or rotating the head. Manual techniques serve their purpose well and is the golden standard in the clinical work, but they lack control of velocity and movement pattern. However, motion simulation platforms enable automatic control of both velocity and movement pattern. One motion simulation platform, named BIRGIT, has been built at the Department of Clinical Neurosciences at Karolinska Institutet but has not yet been in service and require a performance evaluation. The objectives with this thesis is to evaluate the accuracy and precision of BIRGIT and evaluate how bodyweight and movement direction impact the performance. The thesis also evaluate whether it is possible to stabilize the head of the patient during the acceleration phase. Repeated measurements of acceleration with different loads, desired ac- celeration, direction and motion type (rotational and translational), are per- formed. Dummies are used to simulate bodyweight in the performance study and real persons are used in the head stabilization study. Analysis of variance (ANOVA) is the main statistical tool. The results suggest that the platform does not perform equally at dif- ferent load or directions and that there is a bias between desired and true acceleration. The main problems are an inclination of the rails, upon which the chair is mounted, that causes differences between directions and an un- desirable performance characteristic for rotational motions. The stabilization study suggest that the head can be stabilized.
Den vestibulo-okul ̈ara reflexen kan framkallas genom att manuellt rotera eller rycka p ̊a huvudet. Att manuellt framkalla reflexen fungerar i de flesta sam- manhang va ̈l och a ̈r standard i m ̊anga underso ̈kningar. Dock g ̊ar det inte att till fullo kontrollera vare sig hastighet eller ro ̈relsebana perfekt. Emellertid g ̊ar detta att kontrollera genom att anva ̈nda sig av en s ̊a kallad ro ̈relsesimu- leringsplatform. En s ̊adan platform, d ̈opt till BIRGIT, har byggts vid Institutionen f ̈or kliniska neurovetenskaper vid Karolinska Institutet. Denna har ej bo ̈rjat anva ̈ndas ̈annu d ̊a dess prestanda fo ̈rst beho ̈ver utv ̈arderas. Syftet med denna uppsats ̈ar att utva ̈rdera precision och noggrannhet hos BIRGIT. Dessutom, att utv ̈ardera hur kroppsvikt och ro ̈relseriktning inverkar p ̊a prestandan. I arbetet ing ̊ar ̈aven att testa om det a ̈r m ̈ojligt att stabilisera huvudet under accelerationsfasen. Repeterade ma ̈tningar av sann acceleration med olika last, riktning, bo ̈rac- celeration och r ̈orelsetyp (rotation eller sidledes) genomfo ̈rdes. Testdockor anva ̈ndes fo ̈r att simulera lasten i prestandatesterna och riktiga testpersoner anva ̈ndes i huvudstabiliseringsdelen. Variansanalys (ANOVA) var det hu- vudsakliga statistiska verktyget. Resultatet antyder att last och ro ̈relseriktning inverkar p ̊a acceleratio- nen och prestandan och att den sanna accelerationen alltigenom a ̈r la ̈gre a ̈n bo ̈raccelerationen. Det finns tv ̊a sto ̈rre problem hos plattformen, det fo ̈rsta a ̈r att uppha ̈ngningen till stolen lutar och detta resulterar i en skillnad mellan riktningarna (det g ̊ar fortare nedf ̈ors). Det andra problemet a ̈r ett cykliskt uppfo ̈rande na ̈r flera rotationsr ̈orelser skall fo ̈lja p ̊a varandra. Stabiliseringsstudien visade att det g ̊ar att stabilisera huvudet.

Esta dissertação apresenta o desenvolvimento de uma plataforma inercial autônoma com três graus de liberdade para aplicação em estabilização de sensores - por exemplo, gravimétricos estacionários e embarcados - podendo ser utilizada também para estabilização de câmeras. O sistema é formado pela Unidade de Medida Inercial, IMU, desenvolvida utilizando um sensor micro eletromecânico, MEMS - que possui acelerômetro, giroscópio e magnetômetros nos três eixos de orientação - e um microcontrolador para aquisição, processamento e envio dos dados ao sistema de controle e aquisição de dados. Para controle dos ângulos de inclinação e orientação da plataforma, foi implementado um controlador PID digital utilizando microcontrolador. Este recebe os dados da IMU e fornece os sinais de controle utilizando as saídas PWM que acionam os motores, os quais controlam a posição da plataforma. Para monitoramento da plataforma foi desenvolvido um programa para aquisição de dados em tempo real em ambiente Matlab, por meio do qual se pode visualizar e gravar os sinais da IMU, os ângulos de inclinação e a velocidade angular. Testou-se um sistema de transmissão de dados por rádio frequência entre a IMU e o sistema de aquisição de dados e controle para avaliar a possibilidade da não utilização de slip rings ou fios entre o eixo de rotação e os quadros da plataforma. Entretanto, verificou-se a inviabilidade da transmissão em razão da baixa velocidade de transmissão e dos ruídos captados pelo receptor de rádio frequência durante osmovimentos da plataforma. Sendo assim, dois pares de fios trançados foram utilizados fios para conectar o sensor inercial ao sistema de aquisição e processamento.
This work presents the development of a three-degree of freedom autonomous inertial platform for the use in sensors stabilization - for example, stationary and embedded gravimeters. It can also be used to stabilize cameras. The system is composed by the Inertial Measurement Unit, IMU, developed using a micro electromechanical sensor, MEMS - which has an accelerometer, a gyroscope and a magnetometer in the three axes of orientation - and a microcontroller for data acquisition, data processing and data sending to the control and data acquisition system. To control the platform angles and its orientation, a digital PID controller was implemented using a microcontroller. It receives data from the IMU and provides the control signals using the PWM outputs that drive the motors to control the platform position. In order to supervise the platform operation, a real time data acquisition software was developed in Matlab, where IMU signals, inclination angles and angular velocities can be displayed and recorded. Data transmission via radio frequency between the IMU and the data acquisition and control system was tested in order to evaluate the possibility of not using slip rings or wires between the rotation axis and platform frames. This approach was unsuccessful due to the low speed of data transmission and to the noise that affected the radio frequency receiver during the platform\'s movements. In view of that wire was used to directly connect the inertial sensor to the acquisition and processing system.

Master thesis aims to assessment of abrasion on banks of valley reservoir Brno. There was photodocumentation done and current conditions of abraded banks assessed during field survey. There was variables required to detect bottom of brasion cliff and maximal teoretical shift of bank line in the solved location calculated. There was suggested totaly nine types of precaution against other shift of bank line in cross-sections of abraded banks.

碩士
國立交通大學
機械工程系所
107
This thesis mainly studies the design of attitude control system for satellite based on reaction wheel, and develops an attitude control simulation platform to verify the performance of designed attitude controller. The attitude of the satellite is determined by the position, velocity and orientation of the satellite. The stability of the attitude is affected by the uncertainty of the internal parameters and the disturbance of the external interference torque. Therefore, this study analyzed the satellite system dynamic and proposed two control methods applied to the stable satellite attitude of the reaction wheel system. First, a traditional PD controller is used with a feedback linearization method to obtain a robust controller. Because the traditional PD controller cannot effectively suppressed the external disturbance when the parameters are unknown or inaccurate, the method of adaptive control theory is used to identify unknown or uncertain parameters of the system. This adaptive controller identifies system parameters based on the principle of throughput-based control, and makes the state error asymptotically stable by estimating the system parameter process. Since the attitude data of the test platform cannot be obtained directly from the sensor, this study establishes a Kalman filter for multi-sensor fusion and attitude solution. From the simulation and system implementation results, the adaptive control can reach the steady state within 3 seconds when the experimental device is subjected to impulse disturbance, and the convergence time is reduced by 74.1% compared with the PD controller. Therefore, the attitude control can be performed when the parameters such as the system inertia are unknown, and the PD controller must meet the designed motion performance when the inertia is known. The experimental results show that the adaptive controller of this study can resist the nonlinear influence under the influence of different angular momentum of the experimental device, while the convergence time of the traditional PD controller in the low angular momentum is 2.86 times slower than that of the adaptive controller. In the case of high angular momentum, it lasts for more than a minute and even diverges.

abstract: In this work, the hydrodynamics of Suction Stabilization is studied. Suction stabilization was found to stabilize floating platforms/floats in a much better way as compared to the conventional methods. This was achieved by an effective increment in the metacentric height due to the Inverse Slack Tank (IST) effect. The study involves the analysis of the existing designs and optimizing its performance. This research investigates the stability of such floats and the hydrodynamic forces acting on the same for offshore applications, such as wind turbines. A simple mathematical model for the condition of parametric resonance is developed and the results are verified, both analytically and experimentally.
Dissertation/Thesis
Real time working of SSF in heavy wind and rain conditions
Animation explaining working of SSF
Experiment with patio umbrella mounted on SSF
Masters Thesis Mechanical Engineering 2014