Dissertations / Theses on the topic 'Sensors and actuators placement'
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1
Szczepanski, Robert Walter. "Optimal placement of actuators and sensors for vibration control using genetic algorithms." Thesis, University of Newcastle Upon Tyne, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341754.
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Potami, Raffaele. "Optimal sensor/actuator placement and switching schemes for control of flexible structures." Worcester, Mass. : Worcester Polytechnic Institute, 2008. http://www.wpi.edu/Pubs/ETD/Available/etd-042808-124333/.
Abstract:
Dissertation (Ph.D.)--Worcester Polytechnic Institute.Keywords: hybrid system, PZT actuators, performance enchancement, actuator placement, actuator switching. Includes bibliographical references (leaves 102-108).
3
Polyzos, Dimitrios. ""Measuring System Properties & Structured Diagnostics for the Selection of Sensors, Actuators Placement & Eigenstructure Assignment"." Thesis, City University London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.524712.
4
Suwit, Pulthasthan Information Technology & Electrical Engineering Australian Defence Force Academy UNSW. "Optimal placement of sensor and actuator for sound-structure interaction system." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Information Technology and Electrical Engineering, 2006. http://handle.unsw.edu.au/1959.4/38741.
Abstract:
This thesis presents the practical and novel work in the area of optimal placement of actuators and sensors for sound-structure interaction systems. The work has been done by the author during his PhD candidature. The research is concentrated in systems with non-ideal boundary conditions as in the case in practical engineering applications. An experimental acoustic cavity with five walls of timber and a thin aluminium sheet fixed tightly on the cavity mouth is chosen in this thesis as a good representation of general sound-structure interaction systems. The sheet is intentionally so fixed that it does not satisfy ideal boundary conditions. The existing methods for obtaining optimal sensor-actuator location using analytic models with ideal boundary conditions are of limited use for such problem with non-ideal boundary conditions. The method presented in this thesis for optimal placement of actuators and sensors is motivated by energy based approach and model uncertainty inclusion. The optimal placement of actuator and sensor for the experimental acoustic cavity is used to construct a robust feedback controller based on minimax LQG control design method. The controller is aimed to reduce acoustic potential energy in the cavity. This energy is due to the structure-borne sound inside the sound-structure interaction system. Practical aspects of the method for optimal placement of actuator and sensors are highlighted by experimental vibration and acoustic noise attenuation for arbitrary disturbance using feedback controllers with optimal placement of actuator and sensor. The disturbance is experimentally set to enter the system via a spatial location different from the controller input as would be in any practical applications of standard feedback disturbance rejections. Experimental demonstration of the novel methods presented in this thesis attenuate structural vibration up to 13 dB and acoustic noise up to 5 dB for broadband frequency range of interest. This attenuation is achieved without the explicit knowledge of the model of the disturbance.
5
Jha, Akhilesh K. "Vibration Analysis and Control of an Inflatable Toroidal Satellite Component Using Piezoelectric Actuators and Sensors." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/28243.
Abstract:
Inflatable structures have been a subject of renewed interest in recent years for space applications such as communication antennas, solar thermal propulsion, and entry/landing systems. This is because inflatable structures are very lightweight and on-orbit deployable. In addition, they have high strength-to-mass ratio and require minimal stowage volume, which makes them especially suitable for cost-effective large space structures. An inflated toroidal structure (torus) is often used there in order to provide structural support. For these structures to be effective, their vibration must be controlled while keeping the weight low. Piezoelectric materials have become strong candidates for actuator and sensor applications in the active vibration control of such structures due to their lightweight, conformability to the host structure, and distributed nature. In this study, our main focus is to understand the dynamic characteristics of an inflatable torus and to control its vibration using piezoelectric actuators and sensors.
The first part of this study is concerned with theoretical formulations. We use Sanders' shell theory to derive the governing equations of motion for a shell subjected to pressure. To take into account the prestress effects of internal pressure, we use geometric nonlinearity, and to model the follower action of pressure force, we consider the work done by internal pressure during the vibration of the shell. These equations are then specialized to obtain approximate equations presented by previous researchers. We extend this analytical formulation to derive the equivalent forces due to piezoelectric actuators in unimorph and bimorph configurations and include their mass and stiffness effects in the governing equations. A sensor equation is also developed for the shell. The actuator and sensor equations are then written in terms of modal displacements and velocities so as to evaluate their interactions with different vibratory modes.
In the second part, we focus on numerical studies related to an inflated torus. At first, we perform a free vibration analysis of the inflated torus using Galerkin's method. We study how different parameters (aspect ratio, internal pressure, and wall-thickness) of the inflated torus affect the natural frequencies and mode shapes of the inflated torus. We compare the results obtained from the theory used in this research with the results from different approximate theories and commercial finite element codes. The results suggest that the use of an accurate shell theory and pressure effect is very important for the vibration analysis of an inflated torus. Next, the modal behaviors of piezoelectric actuator and sensor are analyzed. A detailed study is done in order to understand how the size and location of actuator and sensor affect the modal forces, the modal sensing constants, and the overall performance for all the considered modes. In order to determine the optimal locations and sizes of actuators and sensors, we use a genetic algorithm. Natural frequencies and mode shapes are calculated considering the passive effects of actuators and sensors. Finally, we attempt the vibration control of the inflated torus using the optimally designed actuators and sensors and sliding mode controller/observer. The numerical simulations show that piezoelectric actuators and sensors can be used in the vibration control of an inflatable torus. The robustness properties of the controller and observer against the parameter uncertainty and disturbances are verified.Ph. D.
6
MURUGAN, JAYA MAHESH. "Vibration monitoring and control of industrial structures." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2858351.
7
Brakna, Mohammed. "Sensor and actuator optimal location for dynamic controller design. Application to active vibration reduction in a galvanizing process." Electronic Thesis or Diss., Université de Lorraine, 2023. https://docnum.univ-lorraine.fr/ulprive/DDOC_T_2023_0152_BRAKNA.pdf.
Abstract:
Les objectifs de cette thèse sont de déterminer un modèle à la fois suffisamment précis mais numériquement exploitable pour proposer des méthodologies de placement de capteurs et d'actionneurs pour le contrôle actif de vibration dans une ligne de galvanisation. La galvanisation consiste à recouvrir un métal (dans notre étude : de l'acier) par une couche protectrice de zinc qui évite la corrosion due à l'air. L'épaisseur de cette couche doit être constante pour garantir les propriétés mécaniques et l'état de surface du produit. Dans une ligne de galvanisation, la bande d'acier en mouvement est chauffée puis plongée dans un bain de zinc liquide avant d'être essorée par des buses projetant de l'air. L'air pulsé, ainsi que la rotation des cylindres d'entrainement de la bande - entre autres - créent des vibrations qui viennent perturber l'essorage et donc la régularité du dépôt de zinc. Un contrôle actif est donc nécessaire, par exemple au moyen d'électro-aimants placés de part et d'autre de la bande d'acier en mouvement. Dans un premier temps, un modèle de comportement de la bande d'acier dans la ligne de galvanisation prenant en compte la présence et la propagation des vibrations a été obtenu par discrétisation spatiale d'une équation aux dérivées partielles. Ce modèle de type espace d'état a été validé en simulation et expérimentalement sur une ligne de galvanisation pilote d'ArcelorMittal Research à Maizières-lès-Metz. Une fois ce modèle établi, l'objectif de l'étude est la recherche du placement optimal de capteurs, pour mesurer le plus efficacement les vibrations de la bande, mais également d'actionneurs pour minimiser l'amplitude de ces vibrations par une loi de commande adaptée. Ces problèmes de placements optimaux sont au cœur des thématiques de contrôle actif des vibrations et se retrouvent dans de nombreux domaines d'application. Une méthode de placement basée sur la maximisation des Grammiens a été proposée en vue de réduire l'impact des perturbations sur le système. Différentes stratégies de contrôle ont été envisagées telles que le retour d'état observé et le retour d'état étendu observé pour améliorer les résultats en tenant compte de l'estimation des perturbations par un observateur PI (proportionnel-intégral). Des résultats de simulations et expérimentaux illustrent les résultats obtenusThe aims of the present PhD thesis are to determine a model that is both sufficiently accurate and numerically exploitable to propose optimal placement of sensors and actuators for active vibration control in a galvanizing line. A continuous hot-dip galvanizing process consists in covering a metal (here: a steel band) by a protective layer of zinc which avoids the corrosion due to the air. The thickness of this layer must be constant to guarantee the mechanical properties and surface condition of the product. In a galvanizing line, the moving steel strip is heated and then immersed in a liquid zinc bath before being wiped out by nozzles projecting air. The air flow, as well as the rotation of the driving rolls, among other things, creates vibrations affecting the wiping process and thus the regularity of the zinc deposit. Active control is therefore necessary, for example by means of electromagnets placed on either side of the moving steel strip. In a first step, a behavioral model of the steel strip taking into account the presence and propagation of vibrations was obtained by spatial discretization of a partial differential equation. This state space model was validated in simulation and experimentally on a pilot galvanizing line of ArcelorMittal Research in Maizières-lès-Metz. Once this model is established, the objective of the study is to find the optimal placement of sensors, to measure the vibrations of the strip as efficiently as possible, but also of actuators to minimize the amplitude of these vibrations by an appropriate control law. These problems of optimal placement are at the heart of the issues of active vibration control and are found in many fields of application. An optimal placement method based on Gramian maximization has been proposed in order to reduce the impact of disturbances on the system. Different control strategies have been considered such as (i) observed state feedback based on Kalman filter and LQ regulator; and (ii) extended observed state feedback to improve the results by also taking into account the disturbance estimation provided by a PI (proportional-integral) observer. Simulation and experimental results illustrate the thesis contributions
8
Perini, Efrain Araujo [UNESP]. "Redução de vibrações de rotores utilizando atuadores magnéticos e sistema de controle feedforward." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/94510.
Abstract:
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perini_ea_me_ilha.pdf: 25219962 bytes, checksum: af8e5bb5738ecda8c45a59f9677a5507 (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Este trabalho apresenta o desenvolvimento de uma análise teórica do desempenho de um sistema de controle ativo utilizando mancais magnéticos como atuadores de não-contato para a redução de vibrações em rotores. São analisados três modelos de rotores, sendo que em um deles aplica-se apenas o controle feedback e os outros são suportados apenas por mancais magnéticos, os quais também são os atuadores do controlador. Assim, Luna arquitetura de controle tipo feedforward é empregada sobreposta ao sistema de controle feedback dos atuadores nestes dois modelos, sendo urna análise realizada em relação ao desempenho do sistema de controle quanto às diferentes geometrias de distribuição de massa acopladas ao eixo do rotor. O enfoque principal deste trabalho é voltado para a análise do desempenho do sistema de controle em função da posição e quantidade dos sensores de erro (onde se deseja minimizar as vibrações) em relação à posição dos atuadores e das forças de excitação. As excitações são do tipo síncronas e sub-síncronas que normalmente aparecem em rotores com elevadas velocidades de rotação, como as turbomáquinas. Também é realizada urna análise das forças de controle necessárias a serem aplicadas pelos atuadores para se obter urna redução dos níveis de vibração do rotor na posição dos sensores de erro do sistema feedforward. A análise é executada empregando modelos de rotores desenvolvidos pelo método da matriz de impedância. Esta pesquisa também apresenta Luna aplicação da técnica de controle Feedforward em acústica, que realiza a depuração da voz para comunicação em ambientes ruidosos.
This research work brings a theoretical analysis of a control system performance that uses magnetic bearings as non-contact actuators to reduce rotor vibrations. It is analyzed three rotor models, in which one of them operates under the feedback control only. The other models are supported by magnetic bearings only, which also are the controller system actuators. Thus, a feedforward control scheme is applied over the feedback control inherent to the AMB control circuit. The analysis is carried out over these two last models regarding to the control performance for different geometry of mass distribution along the rotor. The focus of this work is to analyze the controller performance according to the sensor quantity and placement (where the vibrations are desired to be minimized) regarding to the actuator position and to the exciting forces. The subsynchronous and synchronous excitations are considered here since they frequently occur in high rotating speed rotors, as in the turbomachinery scenario. Also, the control force required by the actuators is monitored according to the sensors placement to reduce the local vibrations level and the analysis was carried out using the impedance matrix rotor modeling. Further, this work brings a modeling and an application of the feedforward active control scheme in the acoustics field used for voice extraction for communication in noisy environments.
9
Perini, Efrain Araujo. "Redução de vibrações de rotores utilizando atuadores magnéticos e sistema de controle feedforward /." Ilha Solteira : [s.n.], 2009. http://hdl.handle.net/11449/94510.
Abstract:
Resumo: Este trabalho apresenta o desenvolvimento de uma análise teórica do desempenho de um sistema de controle ativo utilizando mancais magnéticos como atuadores de não-contato para a redução de vibrações em rotores. São analisados três modelos de rotores, sendo que em um deles aplica-se apenas o controle feedback e os outros são suportados apenas por mancais magnéticos, os quais também são os atuadores do controlador. Assim, Luna arquitetura de controle tipo feedforward é empregada sobreposta ao sistema de controle feedback dos atuadores nestes dois modelos, sendo urna análise realizada em relação ao desempenho do sistema de controle quanto às diferentes geometrias de distribuição de massa acopladas ao eixo do rotor. O enfoque principal deste trabalho é voltado para a análise do desempenho do sistema de controle em função da posição e quantidade dos sensores de erro (onde se deseja minimizar as vibrações) em relação à posição dos atuadores e das forças de excitação. As excitações são do tipo síncronas e sub-síncronas que normalmente aparecem em rotores com elevadas velocidades de rotação, como as turbomáquinas. Também é realizada urna análise das forças de controle necessárias a serem aplicadas pelos atuadores para se obter urna redução dos níveis de vibração do rotor na posição dos sensores de erro do sistema feedforward. A análise é executada empregando modelos de rotores desenvolvidos pelo método da matriz de impedância. Esta pesquisa também apresenta Luna aplicação da técnica de controle Feedforward em acústica, que realiza a depuração da voz para comunicação em ambientes ruidosos.Abstract: This research work brings a theoretical analysis of a control system performance that uses magnetic bearings as non-contact actuators to reduce rotor vibrations. It is analyzed three rotor models, in which one of them operates under the feedback control only. The other models are supported by magnetic bearings only, which also are the controller system actuators. Thus, a feedforward control scheme is applied over the feedback control inherent to the AMB control circuit. The analysis is carried out over these two last models regarding to the control performance for different geometry of mass distribution along the rotor. The focus of this work is to analyze the controller performance according to the sensor quantity and placement (where the vibrations are desired to be minimized) regarding to the actuator position and to the exciting forces. The subsynchronous and synchronous excitations are considered here since they frequently occur in high rotating speed rotors, as in the turbomachinery scenario. Also, the control force required by the actuators is monitored according to the sensors placement to reduce the local vibrations level and the analysis was carried out using the impedance matrix rotor modeling. Further, this work brings a modeling and an application of the feedforward active control scheme in the acoustics field used for voice extraction for communication in noisy environments.
Orientador: Luiz de Paula do Nascimento
Coorientador: Vicente Lopes Junior
Banca: Gilberto Pechoto de Melo
Banca: Kátia Luchese Cavalca Dedini
Mestre
10
Mitwalli, Ahmed Hamdi. "Polymer gel actuators and sensors." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9969.
Abstract:
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. [351]-361).
by Ahmed Hamdi Mitwalli.
Sc.D.
11
Scheidl, Rudolf. "Actuators and Sensors for Smart Systems." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200616.
Abstract:
Smartness of technical systems relies also on appropriate actuators and sensors. Different to the prevalent definition of smartness to be embedded machine intelligence, in this paper elegance and simplicity of solutions is postulated be a more uniform and useful characterization. This is discussed in view of the current trends towards cyber physical systems and the role of components and subsystems, as well as of models for their effective realization. Current research on actuators and sensing in the fluid power area has some emphasis on simplicity and elegance of solution concepts and sophisticated modeling. This is demonstrated by examples from sensorless positioning, valve actuation, and compact hydraulic power supply.
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MOHAMED, MOHAMED ELSAID ELKHAYAT MOATAZBELLAH. "Interface Circuits for Sensors and Actuators." Doctoral thesis, Università degli studi di Pavia, 2018. http://hdl.handle.net/11571/1214860.
Abstract:
The research activity described in this Thesis is the result of three different projects, all dealing with interface circuits for sensors and actuators.
1) Capacitive Humidity sensor with temperature controller and heater integrated in CMOS technology
The first project deals with the design of the integrated interface circuit for accurately controlling the temperature of a CMOS capacitive humidity sensor, with the final goal of allowing self-dignostics and self-calibration of the sensor. The humidity sensor used is equipped with an integrated resistor and a temperature sensor which allow changing and measuring the actual sensor temperature.
This activity concentrated initially on the characterization of the humidity sensor provided by Texas Instruments, with the goal of determining the features and the behavior of the device and identifying the specifications of the integrated interface circuit. A measurement setup based on LabView has been developed to allow controlling the temperature of the sensor with an accuracy of 0.005˚C and measuring both the relative humidity and the temperature.
Based on the sensor measurement results we developed a model of the humidity sensor with built-in heater and thermometer in the Cadence framework, to allow the simulation of the complete system. In this sensor model, all the dynamic effects of the heater and relative humidity variation have been considered, to guarantee proper design of the temperature controller integrated circuit. The temperature controller is designed in CMOS technology; it allows a precise adjustment of the temperature with an accuracy better than 0.1˚C. The circuit is based on an analog control loop with PWM modulator.
The circuit has been fabricated using a 0.35µm CMOS technology.
2) Scaltech28 (test structures in CMOS 28nm)
The second project deals with the design of test structures in CMOS 28nm technology, to evaluate it potential for the implementation of sensor interface circuits in future high-energy physics experiments. This work has been carried out in the frame of project, SCALTECH28, which continues the tradition of other similar studies carried out in previous technology generations for achieving optimal results in IC design for various detectors.
This investigation within the selected 28nm technology had to address basic analysis on the single MOS devices (n-MOS and p-MOS), on passive elements like resistors and capacitors, and finally on basic circuits and system building blocks, among the most critical in the sensor interface circuits for different physics experiments.
The main purpose of the work is to investigate the performance of the 28nm technology in terms of signal processing quality, power consumption, and radiation hardness with respect to previous technological generations. An additional target is to experimentally evaluate radiation damage effects on single devices and on full circuits to develop rad-models for simulations. A test chip including elementary device arrays and dedicated read-out circuits has been developed and fully characterized. In particular, a capacitance to frequency converter has been integrated to measure the matching between different capacitors of a programmable array.Experimental measurements showed that the worst-case measurement for the capacitor pair matching is around 0.98% error at 500fF. This value is compliant to the feasibility of A/D converters for sensor readout with resolution better than 10 bits. It is clear from the results that matching performance is comparable to previous technologies, making the 28nm technology eligible for analog signal processing in front-end circuits for physical experiments and related data converters. Samples have been sent to irradiation facility to be exposed to different radiation doses in order to be re-measured and compared in terms of matching and absolute capacitance values with respect to the measurements done before. Based on the results obtained on the basic devices in 28nm technology, we designed a 14-bit 1MS/s extended range incremental A/D converter composed by the cascade of two resettable second-order sigma-delta modulators. The system is designed for reading out detector arrays in particle physics experiments. The two stages, ideally targeting 9 and 6 bits, respectively, are both based on a cascade of integrators with feed-forward (CIFF) architecture to maximize linearity. If necessary, they can work in pipeline to minimize conversion time. When the conversion of each sample by the two stages is completed, a digital recombination filter produces the overall ADC output word with the required resolution (ENOB) of at least 13 bits and a throughput of 1MS/s at the very low over sampling ratio (OSR) of 16. Each stage, implemented with the switched capacitor technique, consists of two integrators followed by a multi-bit quantizer and a capacitive DAC for the feedback. At the start of each conversion cycle, both analog integrators and the digital filter memory elements are reset. The ADC has been sent for fabrication in 28nm technology. Driving circuit for the piezoelectric actuators in ultrasonic washing machines The third project deals with the design of the driving circuit for the piezoelectric actuators in ultrasonic washing machines. The object of this project concerns the study and design of a driving and control system for an ultrasonic cleaning machine, or more commonly called ultrasonic washing machine. These devices are used in several industrial applications. Ultrasonic washing machines consist of a tank filled with a detergent solvent, an electronic interface circuit and one or more piezoelectric transducers, which are mechanically connected to the tank and electrically to the driving circuit. The driving system is connected from the AC mains and consists of three cascaded stages: a rectifier followed by a boost converter, to regulate the power factor and produce an intermediate DC voltage; a buck converter, to adjust the amplitude of the supply voltage for the piezoelectric transducers; an inverter, to drive the actuators with a square wave at their resonance frequency between 30kHz and 40kHz. A flyback converter has also been designed for generating the auxiliary power supply voltage for all the integrated components in the system. A control system based on an Arduino microcontroller has been developed to adjust the frequency of the square wave to the resonance frequency of the transducer, control the output voltage of the buck converter and read data from a current sensor. The system is designed and implemented on a PCB board of 10cm×15cm. The system has been tested on machined with two different tank sizes.
13
Johnson, David Gary. "Integrating sensors and actuators for robotic assembly." Thesis, University of Hull, 1986. http://hydra.hull.ac.uk/resources/hull:11276.
Abstract:
This thesis addresses the problem of integrating sensors and actuators for closed-loop control of a robotic assembly cell. In addition to the problems of interfacing the physical components of the work-cell, the difficulties of representing sensory feedback at a high level within the robot control program are investigated. A new level of robot programming, called sensor-level programming, is introduced. In this, the movements of the actuators are not given explicitly, but rather are inferred by the programming system to achieve new sensor conditions given by the programmer. Control of each sensor and actuator is distributed through a master-slave hierarchy, with each sensor and actuator having its own slave controller. A protocol for information interchange between each controller and the master is defined. If possible, the control of the kinematics of a robot arm is achieved through the manufacturer's existing control system. Under these circumstances, the actuator slave would be acting as an interface between the generic command codes issued from the central controller, and the syntax of the corresponding control instructions required by the commercial system. Sensor information is preprocessed in the sensor slaves and a set of high-level descriptors, called attributes, are sent to the central controller. Closed-loop control is achieved on the basis of these attributes. The processing of sensor information which is corrupted by noise is investigated. Sources of sensor noise are identified and new algorithms are developed to quantify the noise based on information obtained from the closed-loop servoing. Once the relative magnitudes of the system and measurement noise have been estimated, a Kalman filter is used to weight the sensor information and hence reduce the credibility given to noisy sensors; in the limit ignoring the information completely. The improvements in system performance by processing the sensor information in this way are demonstrated. The sensor-level representation and automatic error processing are embedded in a software control system, which can be used to interface commercial systems as well as purpose-built devices. An'industrial research project associated with the lay-up of carbon-fibre provides an example of its operation. A list of publications resulting from the work in this thesis is given in Appendix E.
14
Dogramadzi, Sanja. "Sensors and actuators in computer controlled colonoscopy." Thesis, University of Newcastle Upon Tyne, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369813.
15
Melin, Oscar, and Matilda Asperot. "Guidelines for placement of sensors : Placement of sensors in public areaswhile consideringcoverage, cost, and performance." Thesis, Jönköping University, JTH, Avdelningen för datavetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-54034.
Abstract:
With the spread of COVID-19, occupancy estimation wason the rise to regulatepeople’smovement in public areasto further decrease the spreadof the diseaseand prepare for future pandemics.Much theory existson the problem of sensor placement, but this theory is mainly treated as a mathematical problem and often not applicable to real-life situationsdue to important real-life factors not being considered. Placing sensors is adifficult task,and it is hard knowingwhere to beginplacing themand what type of sensors to use. The purpose of thisthesis was to help with the problem onplacing sensors by investigatingmethods in a simulated environmentto create guidelines for placing sensors in public areasand evaluatethese placements through a formula.The results are compared to previous researchto prove that it is important to cover different types of hotspots within a building,and where these hotspots canbe foundin general buildings.To truly achieve good sensor placement involves several different things but what is most importantis to be able to track the movement of people, with the number of sensors being as low as possiblewhile still having good coverage.The formula proved to have both benefits and drawbacks, such asthe drawback ofnot consideringwhat kind of sensor is being evaluated. The results should be validatedin a more truthful simulation orin real-lifeto be able to be fully dependent on.
16
Ehresman, Jonathan David. "Integration of actuators and sensors into composite structures." Thesis, Montana State University, 2009. http://etd.lib.montana.edu/etd/2009/ehresman/EhresmanJ0809.pdf.
Abstract:
The need for more efficient wind turbine blades is growing in our society. One step in accomplishing this task would be to make wind turbines blades into smart structures. A smart structure is one that incorporates sensors, complete control systems, and active control devices, in order to shed, or redistribute the load placed on the structure. For wind turbine blades this means changing the shape of the blade profile as it encounters different wind conditions. In order to have active control surfaces functioning on wind turbine blades, the existing blades would have to be retrofitted, and the new blades being manufactured would have to be redesigned. There are different control surfaces to consider: gurney flaps and false wall flaps are two that can perturb the boundary layer across the low pressure side of the wing. A flat plate and blade section test bed will be manufactured in order to gather empirical data from wind tunnel testing. For actuation of the control surface there are many choices: electrical, hydraulic, pneumatic, and electro-hydrostatic. These actuator types will be investigated under a set of criterion to determine the best one for turbine blade application. Sensors will be investigated with respect to their use in sensing strain, temperature, acceleration, humidity, and delamination. Sensors are also used for health monitoring. This helps engineers design under a damage tolerant philosophy as opposed to a safe life structure philosophy. These sensors will be placed into laminates and different surface treatments will be reviewed to find the best configuration for each sensor. The sensor will be cleaned with isopropyl alcohol, dipped in a 20% by mass solution of nitric acid, and submerged in a 20% by mass solution of nitric acid for 10 seconds. Detailed surface images will be taken of sensors with different surface treatments in order to better understand the bonding between the sensor and laminate. These images indicate that submerging the sensors into 20% by mass solution of nitric acid is the best surface treatment.
17
Song, Changsik. "Design and synthesis of molecular actuators and sensors." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41554.
Abstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references.
To date, the most successful conducting polymer actuators are based on polypyrrole, which operates through incorporating and expelling counterions and solvent molecules to balance the charges generated by electrochemical stimuli (swelling mechanism). Although significant progress has been made, there still exists a need for developing new materials that would overcome the intrinsic limitations in the swelling mechanism, such as slow diffusion rate, limited expansion volume, etc. Our group has contributed this area with a different approach -- lecular mechanisms, which utilize a dimensional change of a single polymer chain. We propose two types of molecular mechanisms: contracting and expanding. We proposed earlier a calix[4]arenebased molecular actuator for the contracting mechanism, in which p-dimer formation was proposed as a driving force. In this dissertation, we first confirm by model studies that p-dimer formation can indeed be a driving force for the calix[4]arene-based system. We propose another molecular hinge, binaphthol moiety, for the contracting model. The syntheses of polymers with binaphthols and their characterization, including signatures of oligothiophene interactions, are described. Due to its chirality, we examined the possibilities of the binaphthol polymer as a chiral amine sensor. To create actuators that make use of the expanding model, we propose new conjugated seven-membered ring systems with heteroatoms (thiepin with sulfur and azepine with nitrogen) and their syntheses and characterization will be described. Inspired by the fact that sulfoxide has very low extrusion barrier in the related system, we applied the thiepin molecules to create a peroxide sensor.
(cont.) In addition, during the investigation of phenol functional groups in conducting polymers, we found interesting properties that strategic positioning of phenol groups can render a conjugation-broken meta-linked system just as conductive as a fully conjugated para-linked isomeric system.
by Changsik Song.
Ph.D.
18
Yun, Yeoheung. "Nanotube Sensors and Actuators in Mechanics and Medicine." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1150836513.
19
Aphanuphong, Sutha. "Embedded heaters and sensors for micro SMA actuators." Connect to online resource, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1458441.
20
Anderson, Eric H. (Eric Harold). "Robust placement of actuators and dampers for structural control." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12209.
21
Geykhman, Roman. "Optimal placement of binary actuators in deformable optical systems." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67794.
Abstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 111-113).
Recently, exploration has been conducted into the applicability of binary mechatronics to active figure correction in large optical systems such as space telescopes and ground-based solar-thermal concentrators. This Thesis will continue this exploration. The information-theoretic requirements of the corrective commands required in active optics will be explored to understand the dimensionality of the continuous workspace sampled by binary actuation. In both the minimal expected error and the minimal computation time sense, the optimal discrete workspace is the uniform discrete distribution. A rigorous analogy between binary mechatronics and discrete random variables will be used to show that this optimal workspace is achievable by a linear superposition of actuators with exponentially decreasing influences on the optical surface. It will be proven that elasticity can be exploited to construct mechanisms where constant magnitude actuators exhibit exponentially decaying influences on certain parts of the mechanism, allowing for designs where individual binary actuators correspond to binary bits of the required deformation. A planar truss mechanism designed with this philosophy will be presented and shown to have independent kinematic control of multiple adjacent displacements on its top side. Finally, this design will be shown extend to three dimensions in a manner applicable to optical figure correction. Due to the complexity of mechanisms that meet the optimality criteria, only theoretical analysis will be presented.
by Roman Geykhman.
S.M.
22
Rostain, William. "Engineering of RNA sensors and actuators in living cells." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/95177/.
Abstract:
The aim of synthetic biology is to create a new discipline of engineering based on biological parts, devices and systems. The availability of predictable, programmable tools to sense and to control gene expression is central to our ability to engineer such systems. Ribonucleic acid (RNA) is an attractive building material to create such programmable tools, as RNA-RNA interactions are predictable and RNA secondary structure prediction software has been developed. Design rules for creating such parts using RNA can be established, based on a standardised approach or on structural design rules into which function is implicitly encoded. In this latter case, RNA folding software can be used to create RNA sequence which satisfy generalisable structural characteristics, but are tailored to a specific application. In this work, new design rules for the creation of RNA-based sensors and actuators are developed. The actuator parts are based on riboregulators, but with a circular topology generated through splicing of a ribozyme. The ability of these circular riboregulators to activate transcription of gene expression in E. coli cells is demonstrated. A method for improving these actuators by directed evolution is then tested. Finally, design rules for creating sensors of RNAs based Clustered Regularly Interspaced Short Palindromic Repeat guide RNAs (CRISPR gRNAs) are developed. These gRNA-based sensors can switch states and repress gene expression through a CRISPR-Cas9 based platform, but only in the presence of an arbitrary "trigger" RNA. The rules developed for creating sensors and actuators are characterised in E. coli, but are based on general principles that could be used in other organisms including eukaryotic cells.
23
Sareen, Harpreet. "Cyborg botany : augmented plants as sensors, displays and actuators." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/114063.
Abstract:
Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 94-98).
Plants are photosynthetic eukaryotes with a billion years of evolutionary history. While primarily sessile, they have developed distinctive abilities to adapt to the environment. They are self-powered, self-fabricating, self-regenerating and active signal networks. They carry highly advanced systems to sense and respond to the environment. We strive for such sensing and responses in our electronics; self growing or self repairing abilities in our architecture; and being sustainable at scale in general. The industrial and technological thought process has mostly been devising artificial means or replicating natural systems synthetically. However, I propose a convergent view of technological evolution with our ecology where techno-plant hybrids are created. The approach is to formulate symbiotic associations and to place the technology in conjunction with the plant function(s). In this thesis, I go from the outside to inside the plants in conceiving such synergetic processes and present case studies of their implementation and analysis. I begin with a robot-plant hybrid where the robotic device adds mobility and is triggered with the plant's own signals. Next, lead (II) detection nanosensors are presented which reside inside the leaf of a plant and continuously sample through plant hydraulics. This is followed with a design study for plants with new conductive channels grown inside them and their subsequent use as inconspicuous motion sensors. I conclude with a symbiotic robot that lives on a sunflower plant and automatically trains or directs its growth with onboard lighting. The end result is an augmented-plant society where technology adds non-native functions or redirects the natural processes..
by Harpreet Sareen.
S.M.
24
Kabeya, Kazuhisa III. "Structural Health Monitoring Using Multiple Piezoelectric Sensors and Actuators." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36709.
Abstract:
A piezoelectric impedance-based structural health monitoring technique was developed at the Center for Intelligent Material Systems and Structures. It has been successfully implemented on several complex structures to detect incipient-type damage such as small cracks or loose connections. However, there are still some problems to be solved before full scale development and commercialization can take place. These include: i) the damage assessment is influenced by ambient temperature change; ii) the sensing area is small; and iii) the ability to identify the damage location is poor. The objective of this research is to solve these problems in order to apply the impedance-based structural health monitoring technique to real structures.
First, an empirical compensation technique to minimize the temperature effect on the damage assessment has been developed. The compensation technique utilizes the fact that the temperature change causes vertical and horizontal shifts of the signature pattern in the impedance versus frequency plot, while damage causes somewhat irregular changes.
Second, a new impedance-based technique that uses multiple piezoelectric sensor-actuators has been developed which extends the sensing area. The new technique relies on the measurement of electrical transfer admittance, which gives us mutual information between multiple piezoelectric sensor-actuators. We found that this technique increases the sensing region by at least an order of magnitude.
Third, a time domain technique to identify the damage location has been proposed. This technique also uses multiple piezoelectric sensors and actuators. The basic idea utilizes the pulse-echo method often used in ultrasonic testing, together with wavelet decomposition to extract traveling pulses from a noisy signal. The results for a one-dimensional structure show that we can determine the damage location to within a spatial resolution determined by the temporal resolution of the data acquisition.
The validity of all these techniques has been verified by proof-of-concept experiments. These techniques help bring conventional impedance-based structural health monitoring closer to full scale development and commercialization.Master of Science
25
Lloyd, Justin Michael. "Electrical Properties of Macro-Fiber Composite Actuators and Sensors." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/10013.
Abstract:
Piezoceramic fiber composite (PFC) actuators and sensors offer many advantages over conventional monolithic piezoceramic devices. Conformable, durable and, when equipped with interdigitated electrodes (IDEs), more responsive than regular monolithic devices, PFCs promise to revolutionize the application of piezoelectric materials. Developed by the NASA-Langley Research Center, the Macro-Fiber Composite (MFC) actuator and sensor is the most sophisticated PFC device yet invented. With superior qualities among PFCs in performance, behavior repeatability and manufacturability, the MFC has spawned great interest in the commercial and academic community as a tool in multitudinous engineering applications.
While the MFC's characteristics render it a singularly useful device, limited characterization and modeling research on the MFC exists. Empirically designed and assembled, the MFC is poorly understood, especially in terms of its underlying operating principles, its dependence on design parameters and its electrical properties. The majority of published MFC studies focus on experimental quantification of MFC mechanical and actuation properties, and the research that attempts to model the MFC relies totally on finite element analysis. Published works widely assume that analytical models of the MFC are totally impossible.
Rectifying gaps in the current body of MFC research, this study presents the first accurate analytical model of the static electrical field properties of the MFC. Implementing the techniques of conformal mapping, a branch of complex analysis, the following chapters derive a closed-form, exact analytical solution describing the electrical potential field and electrical field of the MFC's dual-IDE structure. Based on the conformal mapping solution for the MFC's electrical field, the electrical field of the commercially available MFC is examined and analyzed, introducing an intuitive knowledge of the MFC's operation. Demonstrating the utility of this solution in modeling the MFC, this work also predicts the capacitance and induced strain properties of a continuum of potential MFC designs and offers final suggestions on improving the current commercial MFC design. After establishing the theoretical underpinnings of the analytical MFC model, this report derives the conformal mapping solutions for the MFC, discusses the computational application of the resulting equations and then presents the results of numerical analyses executed using the new analytical model.Master of Science
26
Kostner, Stefan [Verfasser]. "Sensors and Actuators for Single Particles and Cells / Stefan Kostner." Aachen : Shaker, 2010. http://d-nb.info/1124365214/34.
27
Savran, Cagri Abdullah 1976. "Broadband active structural control using collocated piezoelectric sensors and actuators." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/89278.
28
McCain, Amy Jean. "Shaped actuators and sensors for local control of intelligent structures." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/46445.
29
Yung, Jeremy Hoyt 1971. "Compensation methodologies for local control using strain actuators and sensors." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10627.
30
Kar, S. B. "Studies on electromechanical sensors and actuators based on conducting polymers." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2005. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2488.
31
Schäfer, Carsten [Verfasser]. "Optimization approaches for actuator and sensor placement and its application to model predictive control of dynamical systems / Carsten Schäfer." München : Verlag Dr. Hut, 2015. http://d-nb.info/1079768459/34.
32
Cormier, Roger. "Isolation of concurrent faults in sensors and actuators in control systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0017/NQ46290.pdf.
33
Tamirisa, Prabhakar A. "Plasma polymerized hydrogel thin films for applications in sensors and actuators." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/19827.
Abstract:
Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2007.Committee Chair: Hess, Dennis W.; Committee Member: Henderson, Cliff L.; Committee Member: Hunt, William D.; Committee Member: Meredith, J. Carson; Committee Member: Prausnitz, Mark R.
34
Sivakumar, Kousik. "Nanowire sensor and actuator." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 5.53 Mb., 108 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1435931.
35
Ferrell, Cynthia. "Robust Agent Control of an Autonomous Robot with Many Sensors and Actuators." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/6791.
Abstract:
This thesis presents methods for implementing robust hexpod locomotion on an autonomous robot with many sensors and actuators. The controller is based on the Subsumption Architecture and is fully distributed over approximately 1500 simple, concurrent processes. The robot, Hannibal, weighs approximately 6 pounds and is equipped with over 100 physical sensors, 19 degrees of freedom, and 8 on board computers. We investigate the following topics in depth: distributed control of a complex robot, insect-inspired locomotion control for gait generation and rough terrain mobility, and fault tolerance. The controller was implemented, debugged, and tested on Hannibal. Through a series of experiments, we examined Hannibal's gait generation, rough terrain locomotion, and fault tolerance performance. These results demonstrate that Hannibal exhibits robust, flexible, real-time locomotion over a variety of terrain and tolerates a multitude of hardware failures.
36
Obal, Michael Walter. "Vibration control of flexible structures using piezoelectric devices as sensors and actuators." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/12025.
37
Daraji, Ali Hossain Alewai. "Active vibration control of flexible structures by optimally placed sensors and actuators." Thesis, University of Newcastle upon Tyne, 2013. http://hdl.handle.net/10443/2484.
Abstract:
The active vibration reduction of plane and stiffened plates was investigated using a genetic algorithm based on finite element modelling to optimise the location of sensors and actuators. The main aspects of this work were: Development of a finite element model for a plate stiffened by beams with discrete sensors and actuators bonded to its surface. Development of a finite element program for steel plates with various symmetrical and asymmetrical stiffening and edge conditions. Development of a genetic algorithm program based on the finite element modelling for the optimisation of the location and number of sensor/actuator pairs and feedback gain. Determination of optimum locations and feedback gain for collocated piezoelectric sensors and actuators on steel plates with various symmetrical and asymmetrical stiffening and edge conditions. Development of fitness and objective functions to locate sensors and actuators. Development of fitness and objective functions to determine the optimal number of sensors and actuators. Development of a reduced search space technique for symmetrical problems. Optimisation of vibration reduction control scheme parameters using the genetic algorithm. Optimisation of the number and location of sensor/actuator pairs and feedback gain to reduce material costs and structural weight and to achieve effective vibration reduction. The modelling was validated by comparison with conventional finite element analysis using ANSYS, and by experiment. The modelling was developed using a quadrilateral isoparametric finite element, based on first order shear deformation theory and Hamilton’s principle, which may be arbitrarily stiffened by beams on its edges. The model can be applied to flat plates with or without stiffening, with discrete piezoelectric sensors and actuators bonded to its surfaces. The finite element modelling was tested for flat and stiffened plates with different boundary conditions and geometries, and the results of the first six natural frequencies were validated with the ANSYS package and experimentally. A genetic algorithm placement strategy is proposed to find the global optimal distribution of two, four, six and ten sensor/actuator pairs and feedback gain based on the minimisation of optimal linear quadratic index as an objective function, and applied to a cantilever plate to attenuate the first six modes of vibration. The configuration of this global optimum was found to be symmetrically distributed about the dynamic axes of symmetry and gave higher vibration attenuation than previously published results with an asymmetrical distribution which was claimed to be optimal. Another genetic algorithm placement strategy is proposed to optimise sensor/actuator locations using new fitness and objective functions based on . This is applied to the same cantilever plate, and was also found to give a symmetrical optimal sensor/actuator configuration. As before, it was found that the optimal transducer locations are distributed with the same axes of symmetry and in agreement with the ANSYS results. A program to simulate the active vibration reduction of stiffened plates with piezoelectric sensors and actuators was written in the ANSYS Parametric Design Language (APDL). This makes use of the finite element capability of ANSYS and incorporates an estimator based on optimal linear quadratic and proportional differential control schemes to investigate the open and closed loop time responses. The complexity of the genetic algorithm problem is represented by the number of finite elements, sensor/actuator pairs and modes required to be suppressed giving a very large search space. In this study, this problem was reduced by the development of a new half and quarter chromosomes technique exploiting the symmetries of the structure. This greatly reduces the number of generations, and hence the computing time, required for the genetic algorithm to converge on the global optimal solution. This could be significant when the technique is applied to large and complex structures. Finally, new fitness and objective functions were proposed to optimise the number of sensor/actuator pairs required for effective active vibration reduction in order to reduce the added cost and weight. The number, location and feedback gain were optimised for the same cantilever plate and it was found that two sensor/actuator pairs in optimal locations could be made to give almost as much vibration reduction as ten pairs.
38
Huang, Wei-Ping. "Quasilinear Control of Systems with Time-Delays and Nonlinear Actuators and Sensors." ScholarWorks @ UVM, 2018. https://scholarworks.uvm.edu/graddis/967.
Abstract:
This thesis investigates Quasilinear Control (QLC) of time-delay systems with nonlinear actuators and sensors and analyzes the accuracy of stochastic linearization for these systems. QLC leverages the method of stochastic linearization to replace each nonlinearity with an equivalent gain, which is obtained by solving a transcendental equation. The idea of QLC is to stochastically linearize the system in order to analyze and design controllers using classical linear control theory. In this thesis, the existence of the equivalent gain for a closed-loop time-delay system is discussed. To compute the equivalent gain, two methods are explored. The first method uses an explicit but complex algorithm based on delay Lyapunov equation to study the time-delay, while the second method uses Pade approximant. It is shown that, under a suitable criterion, Pade approximant can be effectively applied for QLC of time-delay systems. Furthermore, the method of Saturated-Root Locus (S-RL) is extended to nonlinear time-delay systems. It turns out that, in a time-delay system, S-RL always terminates prematurely as opposed to a delay-free system, which may or may not terminate prematurely. Statistical experiments are performed to investigate the accuracy of stochastic linearization compared to a system without time-delay. The impact of increasing the time-delay in the approach of stochastic linearization is also investigated. Results show that stochastic linearization effectively linearizes a nonlinear time-delay system, even though delays generally degrade accuracy. Overall, the accuracy remains relatively high over the selected parameters. Finally, this approach is applied to pitch control in a wind turbine system as a practical example of a nonlinear time-delay system, and its performance is analyzed to demonstrate the efficacy of the approach.
39
Wei, Yu Zhang. "Design and development of new micro-force sensors." Thesis, University of Macau, 2017. http://umaclib3.umac.mo/record=b3691170.
40
Sankar, Sandhya. "INTELLIGENT PLACEMENT OF METERS/SENSORS FOR SHIPBOARD POWER SYSTEM ANALYSIS." MSSTATE, 2008. http://sun.library.msstate.edu/ETD-db/theses/available/etd-09102007-140439/.
Abstract:
Real time monitoring of the shipboard power system is a complex task to address. Unlike the terrestrial power system, the shipboard power system is a comparatively smaller system but with more complexity in terms of its system operation. This requires the power system to be continuously monitored to detect any type of fluctuations or disturbances. Planning metering systems in the power system of a ship is a challenging task not only due to the dimensionality of the problem, but also due to the need for reducing redundancy while improving network observability and efficient data collection for a reliable state estimation process. This research is geared towards the use of a Genetic Algorithm for intelligent placement of meters in a shipboard system for real time power system monitoring taking into account different system topologies and critical parameters to be measured from the system. The algorithm predicts the type and location of meters for identification and collection of measurements from the system. The algorithm has been tested with several system topologies.
41
Swathanthira, Kumar Murali Murugavel Manjakkattuvalasu. "Implementation of an actuator placement, switching algorithm for active vibration control in flexible structures." Link to electronic thesis, 2002. http://www.wpi.edu/Pubs/ETD/Available/etd-1120102-210634.
Abstract:
Thesis (M.S.)--Worcester Polytechnic Institute.Keywords: Actuator placement algorithm; piezoelectric actuators; LQR; Galerkin; supervisory control; active vibration control; FEA; switching policy; dSPACE. Includes bibliographical references (p. 58-64).
42
Mewer, Richard C. "Analysis and Structural Health Monitoring of Composite Plates with Piezoelectric Sensors and Actuators." Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/MewerRC2003.pdf.
43
Newman, Scott M. "Active damping control of a flexible space structure using piezoelectric sensors and actuators." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23517.
Abstract:
Approved for public release; distribution is unlimitedThis thesis details the experimental analysis of an active damping control technique applied to the Naval Postgraduate School's Flexible Spacecraft Simulator using piezoceramic sensors and actuators. The mass property of the flexible arm is varied to study the frequency effects on the Positive Position Feedback (PPF) algorithm. Multi-modal dynamics response is analytically studied using a finite-element model of a cantilevered beam while under the influence of three different control laws: a basic law derived rom the Lyapunov Stability Theorem, PPF and Strain Rate Feedback (SRF). The advantages and disadvantages of using PPF and SRF for active damping control are discussed.
44
Raykar, Vikas Chandrakant. "Position calibration of acoustic sensors and actuators on distributed general purpose computing platforms." College Park, Md. : University of Maryland, 2003. http://hdl.handle.net/1903/39.
Abstract:
Thesis (M.S.) -- University of Maryland, College Park, 2003.Thesis research directed by: Dept. of Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
45
Treanor, Kirk E. "Performance and optimal placement of piezoceramic actuators for shape control of a cantilever beam." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA316163.
46
Gottfarb, Bart Samuel. "Optimal placement of plasma actuators on trucks : A drag reduction study using adjoint methods." Thesis, KTH, Aeroakustik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-203346.
Abstract:
The fuel consumption of vehicles plays an important environmental role and ways of improving the fuel economy is beneficial for a sustainable future. Active flow control is one method that can potentially reduce the aerodynamic drag significantly and therefore the fuel consumption. A plasma actuator introduces momentum in its vicinity and can be used for active control of the flow. This thesis aimed to find the optimal placement of plasma actuators on the A-pillars of a truck, using Reynolds-Averaged Navier-Stokes (RANS) simulations performed with STAR-CCM+. The adjoint solver was used to obtain a sensitivity map of the drag with respect to the variation of momentum. This was then used when the accuracy of this adjoint solution was evaluated by performing parametric studies where the actuation was placed at different locations around the point of flow separation. A simple case consisting in a half-submerged cylinder was first studied as both wind tunnel experiments and Large Eddy Simulations (LES) have been previously performed on this flow case at KTH. When placing actuation on top of the cylinder, the drag reduction obtained with RANS was 4.3% which was comparable to the previous LES work, where the reduction was 4.65%. With the flow separating at 98 degrees in a local cylindrical coordinate system, which starts at the leading edge of the cylinder, the adjoint solution showed that the optimal placement was located at 105 degrees. The actuation was placed at several locations between 90 and 118 degrees and the minimum was found to be located at 106 degrees. The Ground Transportation System (GTS) model representing a generic tractor-trailer combi-nation, both in two and three dimensions, was then used with the same solution procedure. In the two-dimensional case, the flow was found to separate at 63 degrees. The optimal placement predicted by the adjoint solver was 69 degrees, while the parametric study showed the optimal location to be at 75 degrees. The added complexity of an extra dimension resulted in the wind speed having to be lowered in order to produce similar results for the actuation. However, agreement on the optimal location was observed between the two- and three-dimensional cases. In general, the adjoint solver showed varying levels of accuracy between simulations, but still gave a qualitative indication of the optimal placement. A correlation between the point of separation of the flow and the adjoint solution was observed and along with the results from the parametric studies, the optimal placement was concluded to be slightly downstream of the separation point. In order to obtain the exact optimal position, a parametric study is needed for each individual case.
47
Tiberg, Jesper. "An evaluation of algorithms for real-time strategic placement of sensors." Thesis, University of Skövde, School of Humanities and Informatics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-865.
Abstract:
In this work an investigation is performed in whether the algorithms Simultaneous Perturbation Stochastic Approximation (SPSA) and Virtual Force Algorithm (VFA) are suitable for real-time strategic placement of sensors in a dynamic environment. An evaluation of these algorithms is conducted and compared to Simulated Annealing (SA), which has been used before in similar applications.
For the tests, a computer based model of the sensors and the environment in which they are used, is implemented. The model handles sensors, moving objects, specifications for the area the sensors are supposed to monitor, and all interaction between components within the model.
It was the belief of the authors that SPSA and VFA are suited for this kind of problem, and that they have advantages over SA in complex scenarios. The results shows this to be true although SA seems to perform better when it comes to smaller number of sensors to be placed
48
Hixenbaugh, Franklin D. "A study on piezoelectric actuators and sensors for vibration control of flexible space structures." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA274925.
Abstract:
Thesis (M.S. in Systems Technology (Space Systems Operations)) Naval Postgraduate School, September 1993.Thesis advisor(s): Brij N. Agrawal. "September 1993." Includes bibliographical references. Also available online.
49
Miller, Duncan Lee. "Development of resource-constrained sensors and actuators for in-space satellite docking and servicing." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98697.
Abstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 171-177).
Most satellites on-orbit today are not intended to physically approach or interact with other spacecraft. However, the robotic servicing of orbiting assets will be an economically desirable (and often scientifically necessary) capability in future space enterprises. With the right set of tools and technologies, satellites will be able to autonomously refuel, repair, or replace each other. This has the potential to extend mission lifetimes, reduce orbital debris and make space more sustainable. Spacecraft may also assemble on-orbit into larger aggregate spaceflight systems, with applications to sparse aperture telescopes, solar power stations, fuel depots and space habitats. The purpose of this thesis is to address the highest risk elements associated with the docking and servicing of satellites: the sensors, actuators, and associated algorithms. First, a peripheral agnostic robotics platform is introduced, upon which a suite of technology payloads may be developed. Next, a flight qualified docking port for small satellites is presented, and the results detailing its operation in a relevant environment are discussed. In addition, we review a high precision relative sensor designed to enable boresight visual docking. The measurements from this optical camera are applied to a nonlinear estimator to provide the highly accurate sensing necessary for docking. Finally, a free-flying robotic arm is examined and modeled as an experimental payload for the SPHERES Facility on the International Space Station.
by Duncan Lee Miller.
S.M.
50
SADLER, DANIEL J. "DEVELOPMENT OF A NEW MAGNETIC INERCONNECTION TECHNOLOGY FOR MAGNETIC MEMS DEVICE APPLICATIONS." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin983800458.