17 resultados para Motion sensors

em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland


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 In the drilling processes and especially deep-hole drilling process, the monitoring system and having control on mechanical parameters (e.g. Force, Torque,Vibration and Acoustic emission) are essential. The main focus of this thesis work is to study the characteristics of deep-hole drilling process, and optimize the monitoring system for controlling the process. The vibration is considered as a major defect area of the deep-hole drilling process which often leads to breakage of the drill, therefore by vibration analysis and optimizing the workpiecefixture, this area is studied by finite element method and the suggestions are explained. By study on a present monitoring system, and searching on the new sensor products, the modifications and recommendations are suggested for optimize the present monitoring system for excellent performance in deep-hole drilling process research and measurements.

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High dynamic performance of an electric motor is a fundamental prerequisite in motion control applications, also known as servo drives. Recent developments in the field of microprocessors and power electronics have enabled faster and faster movements with an electric motor. In such a dynamically demanding application, the dimensioning of the motor differs substantially from the industrial motor design, where feasible characteristics of the motor are for example high efficiency, a high power factor, and a low price. In motion control instead, such characteristics as high overloading capability, high-speed operation, high torque density and low inertia are required. The thesis investigates how the dimensioning of a high-performance servomotor differs from the dimensioning of industrial motors. The two most common servomotor types are examined; an induction motor and apermanent magnet synchronous motor. The suitability of these two motor types indynamically demanding servo applications is assessed, and the design aspects that optimize the servo characteristics of the motors are analyzed. Operating characteristics of a high performance motor are studied, and some methods for improvements are suggested. The main focus is on the induction machine, which is frequently compared to the permanent magnet synchronous motor. A 4 kW prototype induction motor was designed and manufactured for the verification of the simulation results in the laboratory conditions. Also a dynamic simulation model for estimating the thermal behaviour of the induction motor in servo applications was constructed. The accuracy of the model was improved by coupling it with the electromagnetic motor model in order to take into account the variations in the motor electromagnetic characteristics due to the temperature rise.

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Tämän diplomityön tavoitteena oli tutkia älykkäiden paikoituskäyttöjen markkinoita ja liiketoimintamalleja. Työn pääongelmina oli määritellä alalla käytössä olevaa terminologiaa, määrittää markkinoiden koko paikoitusominaisuudet omaaville kolmivaihetaajuusmuuttajille, tutkia viiden alalla toimivan paikoituskäyttötoimittajan liiketoimintarakenteita ja tuotteita teknisestä näkökulmasta sekä esitellä kaksi teollisuuden käyttökohdetta paikoituskäytölle. Työn sisältö voidaan jakaa neljään eri osioon. Terminologian määrittely- ja markkinatutkimusosiot perustuvat pääasiassa kirjallisuustutkimukseen. Paikoituskäyttöjen toimittajia sekä niiden tuotteita käsittelevä osuus perustuu kirjallisuustutkimukseen sekä teknisiin esitteisiin ja manuaaleihin. Paikoituskäyttöjen sovellusesimerkit on selvitetty haastatteluin. Työ painottuu paikoituskäyttötoimittajien tuotteiden, tuoteominaisuuksien ja tuotetarjonnan tarkasteluun. Työn tuloksena on määritelty paikoituskäyttöjen liiketoiminnan tärkeimmät termit, paikoituskäyttöjen markkinoiden koko sekä markkinoiden koko paikoitusominaisuudet omaavalle kolmivaihetaajuusmuuttajalle. Alalla toimivien paikoituskäyttötoimittajien liiketoimintarakenne on selvitetty, jonka mukaan toimittajat on profiloitu komponentti-, komponenttipaketti-, toimialakeskeisiksi tai automaatiotoimittajiksi. Toimittajien paikoituskäyttötuotteet on luokiteltu viiteen eri luokkaan niiden teknisten ominaisuuksien perusteella. Lisäksi paikoituskäyttöjen suorituskyvyt on selvitetty säätimien momentti-, nopeus-, ja paikoituslaskenta-aikatasojen sekä kenttäväyläliityntöjen suhteen. Työssä kuvatut vanerinsorvausprosessi sekä FMS -materiaalinkäsittelyprosessi esittävät paikoituskäyttöjen potentiaalisia sovelluskohteita.

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The aim of the thesis is to study the principles of the permanent magnet linear synchronous motor (PMLSM) and to develop a simulator model of direct force controlled PMLSM. The basic motor model is described by the traditional two-axis equations. The end effects, cogging force and friction model are also included into the final motor model. Direct thrust force control of PMLSM is described and modelled. The full system model is proven by comparison with the data provided by the motor manufacturer.

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This thesis describes the process of the integration of a real-time simulator environment with a motion platform and a haptic device as a part of the Kvalive project. Several programs running on two computers were made to control the different devices of the environment. User tests were made to obtain information of needed improvements to make the simulator more realistic. Also new ideas for improving the simulator and directions of further research were obtained with the help of this research.

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Sensor-based robot control allows manipulation in dynamic environments with uncertainties. Vision is a versatile low-cost sensory modality, but low sample rate, high sensor delay and uncertain measurements limit its usability, especially in strongly dynamic environments. Force is a complementary sensory modality allowing accurate measurements of local object shape when a tooltip is in contact with the object. In multimodal sensor fusion, several sensors measuring different modalities are combined to give a more accurate estimate of the environment. As force and vision are fundamentally different sensory modalities not sharing a common representation, combining the information from these sensors is not straightforward. In this thesis, methods for fusing proprioception, force and vision together are proposed. Making assumptions of object shape and modeling the uncertainties of the sensors, the measurements can be fused together in an extended Kalman filter. The fusion of force and visual measurements makes it possible to estimate the pose of a moving target with an end-effector mounted moving camera at high rate and accuracy. The proposed approach takes the latency of the vision system into account explicitly, to provide high sample rate estimates. The estimates also allow a smooth transition from vision-based motion control to force control. The velocity of the end-effector can be controlled by estimating the distance to the target by vision and determining the velocity profile giving rapid approach and minimal force overshoot. Experiments with a 5-degree-of-freedom parallel hydraulic manipulator and a 6-degree-of-freedom serial manipulator show that integration of several sensor modalities can increase the accuracy of the measurements significantly.

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A centralized robust position control for an electrical driven tooth belt drive is designed in this doctoral thesis. Both a cascaded control structure and a PID based position controller are discussed. The performance and the limitations of the system are analyzed and design principles for the mechanical structure and the control design are given. These design principles are also suitable for most of the motion control applications, where mechanical resonance frequencies and control loop delays are present. One of the major challenges in the design of a controller for machinery applications is that the values of the parameters in the system model (parameter uncertainty) or the system model it self (non-parametric uncertainty) are seldom known accurately in advance. In this thesis a systematic analysis of the parameter uncertainty of the linear tooth beltdrive model is presented and the effect of the variation of a single parameter on the performance of the total system is shown. The total variation of the model parameters is taken into account in the control design phase using a Quantitative Feedback Theory (QFT). The thesis also introduces a new method to analyze reference feedforward controllers applying the QFT. The performance of the designed controllers is verified by experimentalmeasurements. The measurements confirm the control design principles that are given in this thesis.

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In the work eddy current sensors are described and evaluated. Theoretical part includes physical basics of the eddy currents, overview of available commercial products and technologies. Industrial sensors operation was assessed based on several working modes. Apart from this, the model was created in Matlab Simulink with Xilinx Blockset and then translated into a Xilinx ISE Design Suite compatible project. The performance of the resulting implementation was compared to the existing implementation in the Xilinx Spartan 3 FPGA board with the custom made sensor. Additionally, an introduction to FPGAs and VHDL is presented.

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In this Thesis I discuss the dynamics of the quantum Brownian motion model in harmonic potential. This paradigmatic model has an exact solution, making it possible to consider also analytically the non-Markovian dynamics. The issues covered in this Thesis are themed around decoherence. First, I consider decoherence as the mediator of quantum-to-classical transition. I examine five different definitions for nonclassicality of quantum states, and show how each definition gives qualitatively different times for the onset of classicality. In particular I have found that all characterizations of nonclassicality, apart from one based on the interference term in the Wigner function, result in a finite, rather than asymptotic, time for the emergence of classicality. Second, I examine the diverse effects which coupling to a non-Markovian, structured reservoir, has on our system. By comparing different types of Ohmic reservoirs, I derive some general conclusions on the role of the reservoir spectrum in both the short-time and the thermalization dynamics. Finally, I apply these results to two schemes for decoherence control. Both of the methods are based on the non-Markovian properties of the dynamics.

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This thesis describes the process of design and modeling of instrument for knee joint kinematics measurement that can work for both in-vivo and in-vitro subjects. It is designed to be compatible with imaging machine in a sagittal plane. Due to the invasiveness of the imaging machine, the instrument is designed to be able to function independently. The flexibility of this instrument allows to measure anthropometrically different subject. Among the sixth degree of freedom of a knee, three rotational and one translational degree of freedom can be measured for both type of subject. The translational, proximal-distal, motion is stimulated by external force directly applied along its axis. These angular and linear displacements are measured by magnetic sensors and high precision potentiometers respectively

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Potentiometric ion sensors are a very important subgroup of electrochemical sensors, very attractive for practical applications due to their small size, portability, low-energy consumption, relatively low cost and not changing the sample composition. They are investigated by the researchers from many fields of science. The continuous development of this field creates the necessity for a detailed description of sensor response and the electrochemical processes important in the practical applications of ion sensors. The aim of this thesis is to present the existing models available for the description of potentiometric ion sensors as well as their applicability and limitations. This includes the description of the diffusion potential occurring at the reference electrodes. The wide range of existing models, from most idealised phase boundary models to most general models, including migration, is discussed. This work concentrates on the advanced modelling of ion sensors, namely the Nernst-Planck-Poisson (NPP) model, which is the most general of the presented models, therefore the most widely applicable. It allows the modelling of the transport processes occurring in ion sensors and generating the potentiometric response. Details of the solution of the NPP model (including the numerical methods used) are shown. The comparisons between NPP and the more idealized models are presented. The applicability of the model to describe the formation of diffusion potential in reference electrode, the lower detection limit of both ion-exchanger and neutral carrier electrodes and the effect of the complexation in the membrane are discussed. The model was applied for the description of both types of electrodes, i.e. with the inner filling solution and solidcontact electrodes. The NPP model allows the electrochemical methods other than potentiometry to be described. Application of this model in Electrochemical Impedance Spectroscopy is discussed and a possible use in chrono-potentiometry is indicated. By combining the NPP model with evolutionary algorithms, namely Hierarchical Genetic Strategy (HGS), a novel method allowing the facilitation of the design of ion sensors was created. It is described in detail in this thesis and its possible applications in the field of ion sensors are indicated. Finally, some interesting effects occurring in the ion sensors (i.e. overshot response and influence of anionic sites) as well as the possible applications of NPP in biochemistry are described.

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In this work, image based estimation methods, also known as direct methods, are studied which avoid feature extraction and matching completely. Cost functions use raw pixels as measurements and the goal is to produce precise 3D pose and structure estimates. The cost functions presented minimize the sensor error, because measurements are not transformed or modified. In photometric camera pose estimation, 3D rotation and translation parameters are estimated by minimizing a sequence of image based cost functions, which are non-linear due to perspective projection and lens distortion. In image based structure refinement, on the other hand, 3D structure is refined using a number of additional views and an image based cost metric. Image based estimation methods are particularly useful in conditions where the Lambertian assumption holds, and the 3D points have constant color despite viewing angle. The goal is to improve image based estimation methods, and to produce computationally efficient methods which can be accomodated into real-time applications. The developed image-based 3D pose and structure estimation methods are finally demonstrated in practise in indoor 3D reconstruction use, and in a live augmented reality application.

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Various categories of food packaging indicators namely; VTT, Ageless Eye, Mocon, Åbo Akademi and Impak were selected and incorporated into food trays manufactured at LUT packaging laboratory. Each of these food packaging indicators was used to investigate (visually and qualitatively) the transmission of oxygen through the seal, and tray material, as well as to detect microbial activity within the content of the package. Applications of different methods of gas flushing, content variation and introduction of two distinct levels of oxygen scavengers were employed as treatments to evaluate the packaging performance of the food packaging indicators. Ease of handling of each food packaging indicator was also taken into considerations. Findings showed that for packages, which contained chicken product, the amount of oxygen in the package, measured immediately after the sealing operation on the first day gradually decreased to zero percent by the third day of the storage period. The oxygen level remained at this point throughout the duration of storage for the chicken packages. Besides, level of oxygen in the packages without product continued to increase with the storage time, at moderate rate of 0.1% for 100%N2 and 0.3% for 30%CO2/70%N2 empty packages. More carbon dioxide gas was recorded for packages flushed with 30%CO2/70%N2. Results also revealed that visual analysis of one of the color indicators for example Ageless Eye, conformed to the data derived from the luminescence food-packaging indicator. This shows that packaging operation of the packaging line was considerably stable, and efficient with negligible exception. However, it was found that most of the food packaging indicators investigated in this research study exhibited considerable packaging challenges, such as, reaction with the content of the package (Impak); over sensitivity (Åbo Akademi and Impak); ease of handling problem (Åbo Akademi); and ease of activation problem (VTT indicators). In this study, the strengths and limitations of different indicators were analyzed. This study demonstrates the applicability of various indicators in MAP using chicken package application.

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This literature review aims to clarify what is known about map matching by using inertial sensors and what are the requirements for map matching, inertial sensors, placement and possible complementary position technology. The target is to develop a wearable location system that can position itself within a complex construction environment automatically with the aid of an accurate building model. The wearable location system should work on a tablet computer which is running an augmented reality (AR) solution and is capable of track and visualize 3D-CAD models in real environment. The wearable location system is needed to support the system in initialization of the accurate camera pose calculation and automatically finding the right location in the 3D-CAD model. One type of sensor which does seem applicable to people tracking is inertial measurement unit (IMU). The IMU sensors in aerospace applications, based on laser based gyroscopes, are big but provide a very accurate position estimation with a limited drift. Small and light units such as those based on Micro-Electro-Mechanical (MEMS) sensors are becoming very popular, but they have a significant bias and therefore suffer from large drifts and require method for calibration like map matching. The system requires very little fixed infrastructure, the monetary cost is proportional to the number of users, rather than to the coverage area as is the case for traditional absolute indoor location systems.