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Elfving, Maria. "Hydraulic closed loop control." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-234932.
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The purpose of the thesis work is to investigate methods for closedloop control of hydraulic pressure in transmissions to make them bemore precise. This is desirable since it decreases the fuel consumptionas well as emissions, and improves the driving performance.To be able to study the behaviour of the transmission, a Simulink modelis designed with the parts relevant to the problem, and from this a linearmodel is obtained. Three different controllers are designed andimplemented in the Simulink model, to compare and analyze differentsolutions. The controllers implemented are a PI controller, a PIDcontroller and a LQR controller.The results from the simulation with the different controllers showstep responses to be able to evaluate their individual performance. Theresults show that all of the controllers meet the requirements for a stepreponse under better conditions, but under worse ones the LQR controllerperforms best of the three. The LQR controller is therefore themost suitable of the three controllers for this particular problem.<br>Syftet med det här examensarbete är att undersöka olika metoder för återkopplad reglering av hydrauliskt tryck i en transmission för att göra det mer exakt. Detta är önskvärt eftersom det minskar bränsleåt- gången och utsläpp, och gör även körupplevelsen bättre. För att kunna studera transmission tas en Simulink-modell fram in- nehållande de delar som är relevanta för problemet, och från detta kan en linjär modell erhållas. Tre olika regulatorer tas fram och im- plementeras i Simulink-modellen, för att kunna jämföra och analysera de olika lösningarna. De regulatorer som tas fram är PI-regulator, PID- regulator och LQR-regualator. Resultaten från simuleringen med de olika regulatorerna visar stegs- var under varierande förutsättningar för att kunna utvärdera hur de presterar. Resultaten visar att alla regulatorer uppfyller kraven på ett stegsvar under bättre förhållanden, men LQR-regulatorn presterar bäst under svårare förhållanden. LQR-regulatorn är därför den mest relevanta reglerstrategin för det här problemet av de tre
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Vanichsriratana, Wirat. "Optimal control of fed-batch fermentation processes." Thesis, University of Westminster, 1996. https://westminsterresearch.westminster.ac.uk/item/94908/optimal-control-of-fed-batch-fermentation-processes.
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Optimisation of a fed-batch fermentation process typically uses the calculus of variations or Pontryagin's maximum principle to determine an optimal feed rate profile. This often results in a singular control problem and an open loop control structure. The singular feed rate is the optimal feed rate during the singular control period and is used to control the substrate concentration in the fermenter at an optimal level. This approach is supported by biological knowledge that biochemical reaction rates are controlled by the environmental conditions in the fermenter; in this case, the substrate concentration. Since an accurate neural net-based on-line estimation of the substrate concentration has recently become available and is currently employed in industry, we are therefore able to propose a method which makes use of this estimation. The proposed method divides the optimisation problem into two parts. First, an optimal substrate concentration profile which governs the biochemical reactions in the fermentation process is determined. Then a controller is designed to track the obtained optimal profile. Since the proposed method determines the optimal substrate concentration profile, the singular control problem is therefore avoided because the substrate concentration appears nonlinearly in the system equations. Also, the process is then operated in closed loop control of the substrate concentration. The proposed method is then called "closed loop optimal control". The proposed closed loop optimal control method is then compared with the open loop optimal feed rate profile method. The comparison simulations from both primary and secondary metabolite production processes show that both methods give similar performance in a case of perfect model while the closed loop optimal control provides better performance than the open loop method in a case of plant/model mismatch. The better performance of the closed loop optimal control is due to an ability to compensate for the modelling errors using feedback.
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Jones, Melvin. "Closed loop performance monitoring." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-04122007-115205.
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Mantzaridis, Haralmbos. "Closed-loop control of anaesthesia." Thesis, University of Strathclyde, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338938.
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Norfleet, Walton A. (Walton Arthur) 1973. "Algorithms for closed loop shape control." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8559.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.<br>Includes bibliographical references (p. 147-149).<br>The stretch forming process is used to make structural sheet metal parts in the aerospace industry. The development of stretch forming tools has long been plagued by significant challenges. First, the low production volumes within the aerospace industry and the large numbers of stretch formed parts make the process capital intensive. Second, the development of stretch forming tooling has long been more of an art than a science. This results in poorly designed tools, poor quality parts, and lengthy tooling development cycles. A stretch forming tool capable of rapid reconfiguration was previously designed to address these issues. This tool is used in conjunction with a self-tuning shape control algorithm, which guides the die to the correct shape. There have been many simulations, and lab scale successes with these algorithms, but production scale implementations have experienced difficulties. These problems are related to the method of system identification and process variation. To better understand these issues, analysis and simulation are performed on the various forms of the algorithm. These investigations led to a greater understanding of the algorithms and the synthesis of an improved algorithm. In conclusion, a greater understanding of previously developed algorithms is presented. The system identification is mapped as a Point Spread Function applied through a cyclic convolution. This view provides insight into how the system identification is applied and allows system coupling to be quantified. Furthermore, through improved understanding a new algorithm is synthesized. This new algorithm offers an implementable solution that is optimized for performance, robustness to variation, and ease of use.<br>by Walton A. Norfleet.<br>S.M.
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Nalla, Ajit R. "Closed-loop flow control approaches for VARTM." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 2.86 Mb., 89 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:1430781.
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Corke, Peter Ian. "High-Performance Visual Closed-Loop Robot Control." Connect to thesis, 1994. http://repository.unimelb.edu.au/10187/1392.
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This thesis addresses the use of monocular eye-in-hand machine vision to control the position of a robot manipulator for dynamically challenging tasks. Such tasks are defined as those where the robot motion required approaches or exceeds the performance limits stated by the manufacturer.<br>Computer vision systems have been used for robot control for over two decades now, but have rarely been used for high-performance visual closed-loop control. This has largely been due to technological limitations in image processing, but since the mid 1980sadvances have made it feasible to apply computer vision techniques at a sufficiently high rate to guide a robot or close a feedback control loop. Visual servoing is the use of computer vision for closed-loop control of a robot manipulator, and has the potential to solve a number of problems that currently limit the potential of robots in industry and advanced applications.<br>This thesis introduces a distinction between visual kinematic and visual dynamic control. The former is well addressed in the literature and is concerned with how the manipulator should move in response to perceived visual features. The latter is concerned with dynamic effects due to the manipulator and machine vision sensor which limit performance and must be explicitly addressed in order to achieve high-performance control. This is the principle focus of the thesis.<br>In order to achieve high-performance it is necessary to have accurate models of the system to be controlled (the robot) and the sensor (the camera and vision system).Despite the long history of research in these areas individually, and combined in visual servoing, it is apparent that many issues have not been addressed in sufficient depth, and that much of the relevant information is spread through a very diverse literature. Another contribution of this thesis is to draw together this disparate information and present it in a systematic and consistent manner. This thesis also has a strong theme of experimentation. Experiments are used to develop realistic models which are used for controller synthesis, and these controllers are then verified experimentally.
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Ettaleb, Lahoucine. "Control loop performance assessment and oscillation detection." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0017/NQ46341.pdf.
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Bao, Lei. "Source-channel coding for closed-loop control." Licentiate thesis, Stockholm, Communication Theory Lab, School of Electrical Engineering, Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3980.
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Chen, Jun. "Control system based loop and process monitoring." Thesis, University of Glasgow, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312530.
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Wilhelms, John, and Marcus Trulsson. "Open Loop Control of Piezoelectric Cantilever Speaker." Thesis, Linköpings universitet, Reglerteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-122363.
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Actuating a cantilever piezoelectric element over a frequency spectrum, the movement will show resonances and hysteresis behavior not present in the input signal. Excursion modeling and open loop control of a cantilever piezoelectric bimorph actuator was studied in this thesis, with the aim to enhance the actuator's movement to more accurately render audible input. This actuator has lower energy consumption and presents new possibilities for speaker design in constrained situations compared to conventional micro speaker technology. Much work has previously been done to model piezoelectric cantilever actuators below the first and second resonance frequency. This thesis describes a physical linear model and its modifications to render the eight first resonance frequencies below 20 kHz, as well as the model's performance in open loop control. This was performed on a single piezoelectric beam and a concept piezoelectric speaker. For the single piezoelectric beam the model was validated with fair overall result below 3 kHz. The model is suggested to have fair overall behavior up to 15 kHz. Above 15 kHz the experiments showed changed characteristics that were not modeled well. The open loop control had the intended behavior but severe resonances and physical constraints made the open loop control ineffective to enhance the sound rendering. Two different approaches were used for trying to improve the sound rendering based on an excursion model. These approaches did not generate useful methods but present viable input to future work with this type of speaker structure, for reducing disharmonics and creating a physical design tool for sound simulation. For the concept piezoelectric speaker, due to difficulties in measuring excursion, the model could not be validated. This made the approaches for enhancing the sound rendering ineffective. However, it can be concluded from the concept speaker that the cantilever piezoelectric speaker technology has qualities that could compete with the conventional micro speaker technology. Challenges remain in electric hardware, actuator configuration and acoustic design as well as in fine tuned signal processing for the concept speaker to become a competitive product.
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Wenzel, Brian Jeffrey. "CLOSED-LOOP ELECTRICAL CONTROL OF URINARY CONTINENCE." Case Western Reserve University School of Graduate Studies / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=case1120932206.
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Shaw, Feng-Rong. "Repetitive control of closed loop material testing /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487757723996636.
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Whiting, Ian Martin. "Closed loop digital control of electrohydraulic systems." Thesis, University of Bath, 1987. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375516.
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Ambike, Ajit Dilip. "Closed-loop real-time control on distributed networks." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/1079.
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This thesis is an effort to develop closed-loop control strategies on computer networks and study their stability in the presence of network delays and packet losses. An algorithm using predictors was designed to ensure the system stability in presence of network delays and packet losses. A single actuator magnetic ball levitation system was used as a test bed to validate the proposed algorithm. A brief study of real-time requirements of the networked control system is presented and a client-server architecture is developed using real-time operating environment to implement the proposed algorithm. Real-time performance of the communication on Ethernet based on user datagram protocol (UDP) was explored and UDP is presented as a suitable protocol for networked control systems. Predictors were designed based on parametric estimation models. Autoregressive (AR) and autoregressive moving average (ARMA) models of various orders were designed using MATLAB and an eighth order AR model was adopted based on the best-fit criterion. The system output was predicted several steps ahead using these predictors and control output was calculated using the predictions. This control output output was used in the events of excessive network delays to maintain system stability. Experiments employing simulations of consecutive packet losses and network delays were performed to validate the satisfactory performance of the predictor based algorithm. The current system compensates for up to 20 percent data losses in the network without loosing stability.
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Al, Soraihi Ghassan, and ghassan soraihi@aramco com. "Control loop performance monitoring in an industrial setting." RMIT University. Electrical and Computer Engineering, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080108.125446.
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The wide range of applications for single input single output controllers have encouraged interest in monitoring their performance. Over the past two decades researchers in the area have found many performance enhancement opportunities by applying these techniques. These are most evident in large operational plants with hundreds of controllers being monitored at the same time. Early performance measures were based on minimum variance control as a benchmark for controller performance. Many other procedures have since emerged that have improved the level of accuracy in these performance measures. In addition, these improvements made it easier to implement control loop performance monitoring in large industrial settings. This thesis looks at the performance measures in use for single input single output controllers. The work here looks at incorporating these different measures for a specific manufacturing plant. Ways of identifying the goals and objectives of controllers in a system are presented. Furthermore, measures are proposed that most accurately indicate if these goals and objectives are being met. The concept is demonstrated on a distillation system in a gas plant. It is shown how using these objective driven techniques can provide the user with sound results. These results do not require much user analysis to identify sources of problems and areas of improvement.
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Johansson, Henrik. "Gain Scheduled Missile Control Using Robust Loop Shaping." Thesis, Linköping University, Department of Electrical Engineering, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1529.
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<p>Robust control design has become a major research area during the last twenty years and there are nowadays several robust design methods available. One example of such a method is the robust loop shaping method that was developed by K. Glover and D. C. MacFarlane in the late 1980s. The idea of this method is to use decentralized controller design to give the singular values of the loop gain a desired shape. This step is called Loop Shaping and it is followed by a Robust Stabilization procedure, which aims to give the closed loop system a maximum degree of stability margins. In this thesis, the robust loop shaping method is used to design a gain scheduled controller for a missile. The report consists of three parts, where the first part introduces the Robust Loop Shaping theory and a Gain Scheduling approach. The second part discusses the missile and its characteristics. In the third part a controller is designed and a short analysis of the closed loop system is performed. A scheduled controller is implemented in a nonlinear environment, in which performance and robustness are tested. Robust Loop Shaping is easy to use and simulations show that the resulting controller is able to cope with model perturbations without considerable loss in performance. The missile should be able to operate in a large speed interval. There, it is shown that a single controller does not stabilize the missile everywhere. The gain scheduled controller is however able to do so, which is shown by means of simulations.</p>
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Pothier, Raymond Peter. "Closed-loop temperature control of friction stir welding." Thesis, Nelson Mandela Metropolitan University, 2015. http://hdl.handle.net/10948/10362.
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This study develops and presents a friction stir weld (FSW) quality assurance tool based on control of weld zone temperature. Apart from correct tool geometry, tool tilt angle, traverse speed and forge force during welding, one important requirement is that the weld material be sufficiently plasticised (softened). The level of plasticisation is related to weld zone temperature which is primarily dependent on spindle speed, traverse speed and forge force. When all other conditions are correct, sufficiently plasticised material flows around and consolidates behind the tool without the production of voids in the weld. Typically, weld temperature varies along the weld length which may result in variations in weld quality. Weld zone temperature control makes constant weld zone temperature possible. In this study, thermocouple sensors were embedded in the FSW tool and a weld zone temperature control algorithm was developed. Spindle speed was the actuating mechanism for controlling weld temperature. The system was modelled and controllers were designed using Matlab tools. The system was simulated and the performance was compared to the system performance during welding. The control system ensures that the weld zone temperature can be maintained irrespective of the presence of thermal disturbances. Tensile testing was conducted which confirmed a range of temperature in which the welds resulted in consistent strength.
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Huang, Biao. "Multivariate statistical methods for control loop performance assessment." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21580.pdf.
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Zhang, Zhenyu. "Closed-Loop Flow Control for Boundary Layer Instabilities." Thesis, Queen Mary, University of London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504556.
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Since O. Reynolds' experiment revealed the transition from laminar state to turbulence in pipe flow (1883), numerous efforts had been exerted in order to understand the mechanism. Linear hydrodynamic stability theory was established in the first half ofthe twentieth century. This theory predicts the growth of small disturbances during the initial stage of transition. As an important achievement, the Tollmien-Schlichting (T-S) instability, which represents the initial evolution of disturbances in two dimensional shear flows, has been described and verified in boundary layer experiments. Once the enonnous benefits from the delay of flow transition (and then turbulence) were acknowledged, diversities of flow control techniques have been motivated. In fact, some relevant techniques have already been demonstrated, such as the drag reduction oflarge aeroplane through laminar flow control. At the same time, the development of control theory makes it possible to implement deliberately designed systems to control transitional flows. After decades of advances with passive control, the concept of active control became widely accepted in fluid mechanics in the early 1980s. . The study in this thesis attempts to find an efficient closed-loop active control scheme to cancel the unstable Tollmien-Schlichting waves in a transitional boundary layer flow. The T-S instabilities was simulated by numerical solutions of the linearised Navier-Stokes equation system. Controllers were designed according to the frequency characteristics ofthe disturbed flowfield and implemented on the basis of the classical control theory in frequency domain. The perfonnance of controllers in the disturbed boundary layer flow along a flat plate were evaluated through numerical simulations and then validated by experiments.
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Wiese, Daniel Philip. "Systematic adaptive control design using sequential loop closure." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104197.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 211-219).<br>This thesis presents a new, systematic method of synthesizing an output feedback adaptive controller for a class of uncertain, non-square multi-input/multi-output systems. The control design process consists of first designing an inner-loop controller for a reduced order plant model to enforce command tracking of selected inner-loop variables, with an adaptive element used to accommodate parametric uncertainties in the plant. Once this inner-loop control design is complete, an outer-loop is then designed which prescribes the inner-loop commands to enforce command tracking of selected outer-loop variables. The main challenge that needs to be addressed when designing the inner-loop controller is the determination of a corresponding square and strictly positive real transfer function. The first contribution of this thesis is the design of a new procedure to synthesize two gain matrices that allow the realization of such a transfer function, thereby allowing a globally stable adaptive output feedback law to be generated. The unique features of this output feedback adaptive controller are a baseline controller that uses a Luenberger observer, a closed-loop reference model, manipulations of a bilinear matrix inequality, and the Kalman- Yakubovich lemma. Using these features, a simple design procedure is proposed for the adaptive controller, and the corresponding stability property is established. The outer-loop controller is designed around the plant with existing adaptive inner-loop controller such that global stability of the closed-loop system is guaranteed. The design of the outer-loop uses components of a closed-loop reference model in a judicious manner which enables a modular approach, without any re-design of the inner-loop controller. In addition, this architecture facilitates the use of an additional state-limiter to enforce desired limits on the state variables. A numerical example based on a scramjet powered, generic hypersonic vehicle model is presented, demonstrating the efficacy of the proposed control design. The six-degree-of-freedom nonlinear vehicle model is linearized, giving the design model for which the controller is synthesized. The adaptive output feedback controller is then applied to an evaluation model, which is nonlinear, coupled, and includes actuator dynamics, and it is shown to result in stable tracking in the presence of uncertainties that destabilize the baseline controller. Benefits of various aspects of the sequential and modular control design as well as its adaptive components are clearly illustrated in this numerical example.<br>by Daniel Philip Wiese.<br>Ph. D.
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Palliyaguru, Lalinda Niroshana. "Investigation of Closed-Loop Control of Polyatomic Molecules." Diss., Temple University Libraries, 2008. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/16646.
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Chemistry<br>Ph.D.<br>ABSTRACT Investigation of Closed-Loop Control of Polyatomic Molecules Lalinda N. Palliyaguru Doctor of Philosophy Temple University, 2009 Doctoral Advisory Committee Chair: Prof. Robert J. Levis Experimental results that are based on mass spectral data, in this thesis includes ionization/fragmentation of DMMP and CH2BrI in strong femtosecond laser fields, coherent control using closed-loop optimization method for bond dissociation in both DMMP and CH2BrI, as well as application of closed-loop control as a detection method for air borne organophosphates such as DMMP. Investigation of mass spectral data as a function of laser field intensity, wavelength, and polarization provided details of ionization/fragmentation of DMMP and CH2BrI. Furthermore, quantum mechanical calculations carried out with Gaussian 03 Computational package were used to analyze the mass spectral data. The analysis of the peak splitting pattern of the molecular fragments reveals that Coulomb explosion as well as the photodissociation of CH2BrI produces the TOF mass spectral product distribution. We observed a considerable enhancement of photodissociation of CH2BrI in strong elliptically polarized femtosecond laser fields. The enhanced photodissociation of CH2BrI in circularly polarized fields could be due to the interaction with both parallel and perpendicular electronic transitions that cause the efficient dissociation of C-I and C-Br bonds. We also demonstrate the selective dissociation of C-I and C-Br bonds using closed-loop optimal control method. The fragmentation processes of polyatomic molecules induced by an intense laser field exhibit sensitive dependence on the laser characteristics such as intensity, pulse duration, wavelength, and shape of the temporal pulse envelope. Adaptive laser pulse shaping can control the fragmentation of methyl/methoxy groups in dimethyl methylphosphonate (DMMP), a simulant for nerve agent Sarin. The exploitation of the sensitivity of molecular fragmentation to laser pulse shapes represents a new way to discriminate molecular identity. Here we have shown manipulation of the branching M-(OCH3)+/M-(CH3)+, M-2(CH3)+/M-(CH3)+ and M-(OCH3)+/M-2(CH3)+ fragment ion ratios for DMMP in the presence of complex background in the extraction region of TOF spectrometer using tailored femtosecond laser pulses. We also investigated the TOF mass spectra of DMMP as a function of laser field parameters, such as intensity, wavelength, polarization, and linear chirp. We positively identified that non-sequential ionization plays a role in the fragmentation process of DMMP.<br>Temple University--Theses
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Hardwicke, K. R. "A SELF TUNING PHASE-LOCKED LOOP." International Foundation for Telemetering, 1992. http://hdl.handle.net/10150/608941.
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International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California<br>The uncertainty in the gain of voltage controlled crystal oscillators (VCXOs) used in the
implementation of certain analog phase-locked loops (PLLs) suggests some form of
automatic tuning algorithm, both for pretuning and during operation. This paper proposes
an adaptive PLL (APLL) algorithm to fill this need for PLLs used in the recovery of tones
in noise. This algorithm makes use of a resonant error algorithm to remove the effects of
VCXO noise, measurement noise, and parasitic poles. Both classical convergence
theorems and robustness theorems that indicate the functionality of the proposed algorithm
are given. Finally, the implementation of this algorithm is considered.
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Inyiama, Fidelis Chidozie. "Active control of hydrodynamic slug flow." Thesis, Cranfield University, 2013. http://dspace.lib.cranfield.ac.uk/handle/1826/7996.
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Multiphase flow is associated with concurrent flow of more than one phase (gas-liquid, liquid-solid, or gas-liquid-solid) in a conduit. The simultaneous flow of these phases in a flow line, may initiate a slug flow in the pipeline. Hydrodynamic slug flow is an alternate or irregular flow with surges of liquid slug and gas pocket. This occurs when the velocity difference between the gas flow rate and liquid flow rate is high enough resulting in an unstable hydrodynamic behaviour usually caused by the Kelvin-Helmholtz instability.
Active feedback control technology, though found effective for the control of severe slugs, has not been studied for hydrodynamic slug mitigation in the literature. This work extends active feedback control application for mitigating hydrodynamic slug problem to enhance oil production and recovery.
Active feedback Proportional-Integral (PI) control strategy based on measurement of pressure at the riser base as controlled variable with topside choking as manipulated variable was investigated through Olga simulation in this project. A control system that uses the topside choke valve to keep the pressure at the riser base at or below the average pressure in the riser slug cycle has been implemented. This has been found to prevent liquid accumulation or blockage of the flow line.
OLGA (olga is a commercial software widely tested and used in oil and gas industries) has been used to assess the capability of active feedback control strategy for hydrodynamic slug control and has been found to give useful results and most interestingly the increase in oil production and recovery. The riser slugging was suppressed and the choke valve opening was improved from 5% to 12.65% using riser base pressure as controlled variable and topside choke valve as the manipulated variable for the manual choking when compared to the automatic choking in a stabilised operation, representing an improvement of 7.65% in the valve opening. Secondly, implementing active control at open-loop condition reduced the riser base pressure from 15.3881bara to 13.4016bara.
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Aude, E. P. L. "Closed-loop identification procedures and aspects of self-tuning control." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377482.
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Papageorgiou, George. "Robust control system design : H∞ loop sharing and aerospace applications." Thesis, University of Cambridge, 1998. https://www.repository.cam.ac.uk/handle/1810/272494.
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Guidi, Hernan. "Open and closed-loop model identification and validation." Pretoria : [s.n.], 2009. http://upetd.up.ac.za/thesis/available/etd-07032009-170311/.
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Clarkson, P. J. "Modelling and control of stepping motor systems." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384410.
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Greenwood, David. "Benchmarking and advanced control for hot strip finishing mills." Thesis, University of Strathclyde, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275182.
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Rasman, Brandon Gerald. "Sensorimotor loop delays in the control of human stance." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/59843.
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Maintaining upright stance involves a time-critical process in which the central nervous system monitors postural orientation and modulates muscle activity accordingly. Visual, vestibular and somatosensory systems detect body motion that the balance controller utilizes to update standing control. The time delays between motor output and the resulting sensory feedback are expected and likely accommodated for. Consequently, we perceive whole-body movement as being a consequence of our own actions. Balance control, however, also involves processes that do not rely on conscious perception, allowing us to maintain standing balance almost effortlessly. Recent studies have demonstrated that both the perception and vestibular control of balance are modulated when sensory signals of whole-body movement do not match self-generated ankle torques. The aim of this thesis was to explore the temporal properties of the sensorimotor loops driving the perception and vestibular control of standing balance. Using a robotic balance simulator, experimentally-induced time delays were introduced between human participant’s ankle-produced torques and body movement. The first experiment used a psychophysical design to determine what delay is needed for humans to perceive a change in balance control. All participants were able to perceive a 300 ms delay with 100% success, with an average 69% correct threshold of 155 ms. In the second experiment, participants were exposed to a virtual vestibular perturbation while they balanced their body at different induced delays. Vestibular-evoked muscle responses attenuated with increasing loop delays, falling to amplitudes 84% smaller than baseline when a 500 ms delay was introduced between the produced torques and body movement. This is the first study to explore the time domain relationship between sensory and motor signals in standing, and the results reveal and describe temporal constraints of the sensorimotor control of balance. The present findings will act as springboard for studying postural control mechanisms in the future, encouraging the use of this robotic simulator to alter sensorimotor relationships during ongoing balance control. Using interventions like induced delays, we can decipher the natural processes that govern posture, and explore the adaptability and plasticity of these systems.<br>Education, Faculty of<br>Graduate
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Hodge, Steven Eric. "Discrete-time closed-loop control of a hinged wavemaker." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26704.
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The waves produced by a flap-type wavemaker, hinged in the middle, are modelled using first-order linear wavemaker theory. A simplified closed-loop, discrete-time system is proposed. This includes a proportional
plus integral plus derivative (PID) controller, and the wavemaker in order to compare the actual wave spectral density with the desired wave spectral density at a single frequency. Conventional discrete-time control theory is used with the major difference being the use of a relatively long timestep duration between changes in waveboard motion.
The system response is calculated for many controller gain combinations
by the computer simulation program CBGANES. System stability is analyzed for the gain combinations by using two different methods. One method is an extension of the Routh criterion to discrete-time and the other is a state-space eigenvalue approach. The computer simulation and the stability analysis provide a means for selecting possible controller gains for use at a specific frequency in an actual wave tank experiment.
The computer simulation performance response and the two stability analyses predict the same results for varying controller gains. It is evident that integral control is essential in order to achieve a desired response for this long duration timestep application. The variation in discrete timestep duration and in desired spectral density (an indirect indication of frequency variation) provide variation in the constraints on controller gain selection. The controller gain combinations yielding the fastest stable response at a single frequency are for large proportional gain and small integral and derivative gains.<br>Applied Science, Faculty of<br>Mechanical Engineering, Department of<br>Graduate
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Pereira, E. "Adaptive closed-loop control of arterial pressure during anaesthesia." Thesis, University of Bristol, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379565.
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Fenn, Ralph Christian. "Closed-loop control of forming stability during metal stamping." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/13966.
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Lee, Daniel C. (Daniel Chonghwan). "On open-loop admission control into a queueing system." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12776.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1992.<br>Includes bibliographical references (leaves 156-159).<br>by Daniel Chonghwan Lee.<br>Ph.D.
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Bakkestuen, Robert S. (Robert Scott). "Closed loop control of forming stability during aluminum stamping." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/12048.
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Tate, Allan Robert. "Closed loop force control for a robotic grinding system." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/15031.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1986.<br>MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING<br>Bibliography: leaves 175-179.<br>by Allan Robert Tate.<br>M.S.
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Lopes, Rafael Anderson Martins. "Aircraft identification applied to closed loop control system design." Instituto Tecnológico de Aeronáutica, 2006. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=904.
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In the present work, the influence of maneuver design for stability derivatives of aerodynamic forces and moments identification in the performance of closed loop control systems is evaluated, where two maneuvers largely used in aeronautical industry - doublet and 3211 - are compared to a maneuver of restricted use in aeronautical industry, but already well known in identification - the PRBS. This evaluation is divided in two steps: in the first, it is performed the identification with each of the maneuvers and then a crosschecking of the obtained models, computing the mean quadratic prediction error; in the second, the identified models are analytically linearized and use in a bank angle tracker. The calculated gains are then applied to the nonlinear model and the performance indices computed, as peak time and maximum overshoot, of step response with each gain set. The crosschecking showed the superior capacity of PRBS maneuver to capture the dynamics of the reference model, where the prediction error was relatively small for all models when compared to the response to doublet. With the 3211 data set, the error of the model identified with doublet was significantly larger than 3211 and PRBS models error, that had similar performance, however lightly better for the PRBS. With the PRBS data set, the PRBS error was relatively small, while the doublet and 3211 models error was relatively large. This result shows the direct relation of the maneuvers frequency spectra and the excitation persistence characteristic in the identified models.With an exigent performance requirement to the bank angle tracker, it was possible to expose the differences between the models and verify the influence of these differences in the closed loop response. In an equivalent form, as observed in the crosschecking analysis, the control system designed with the PRBS model showed performance indices closer to the target in comparison to the control system designed with the 3211 model, that was significatively better than the system designed with the doublet model. The closed loop amplified the difference between the models, and depending on the control system structure, these differences can be still larger. Finally, a practical application on aircraft identification and control is presented and discussed.
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Harris, Jr Frederick Bernard. "GNSS Hardware-In-The-Loop Formation and Tracking Control." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/71380.
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Formation and tracking control are critical for of today's vehicle applications in and this will be true for future vehicle technologies as well. Although the general function of these controls is for data collection and military applications, formation and tracking control may be applied to automobiles, drones, submarines, and spacecraft. The primary application here is the investigation of formation keeping and tracking solutions for realistic, real-time, and multi-vehicle simulations. This research explores the creation of a predictive navigation and control algorithm for formation keeping and tracking, raw measurement data collection, and building a real-time GNSS closed HWIL testbed for simulations of different vehicles. The L1 frequency band of the Global Positioning System (GPS) constellation is used to observe and generate raw measurement data that encompasses range, pseudo-range, and Doppler frequency. The closed HWIL simulations are implemented using Spirent's Communication Global Navigation Satellite system (GNSS) 6560 and 8000 hardware simulators along with Ashtech, G-12 and DG-14, and Novetel OEM 628 receivers. The predictive navigation control is similar to other vision-based tracking techniques, but relies mainly on vector projections that are controlled by acceleration, velocity magnitude, and direction constraints to generate realistic motion.
The current state of the testbed is capable of handling one or more vehicle applications. The testbed can model simulations up to 24 hours. The vehicle performance during simulations can be customized for any required precision by setting a variety of vehicle parameters. The testbed is built from basic principles and is easily upgradable for future expansions or upgrades.<br>Master of Science
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Lee, Seong-Rae. "Self-tuning control application to closed loop material testing /." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487598748019076.
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Harris, Frederick Bernard Jr. "GNSS Hardware-In-The-Loop Formation and Tracking Control." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/71380.
Full textAbstract:
Formation and tracking control are critical for of today's vehicle applications in and this will be true for future vehicle technologies as well. Although the general function of these controls is for data collection and military applications, formation and tracking control may be applied to automobiles, drones, submarines, and spacecraft. The primary application here is the investigation of formation keeping and tracking solutions for realistic, real-time, and multi-vehicle simulations. This research explores the creation of a predictive navigation and control algorithm for formation keeping and tracking, raw measurement data collection, and building a real-time GNSS closed HWIL testbed for simulations of different vehicles. The L1 frequency band of the Global Positioning System (GPS) constellation is used to observe and generate raw measurement data that encompasses range, pseudo-range, and Doppler frequency. The closed HWIL simulations are implemented using Spirent's Communication Global Navigation Satellite system (GNSS) 6560 and 8000 hardware simulators along with Ashtech, G-12 and DG-14, and Novetel OEM 628 receivers. The predictive navigation control is similar to other vision-based tracking techniques, but relies mainly on vector projections that are controlled by acceleration, velocity magnitude, and direction constraints to generate realistic motion.
The current state of the testbed is capable of handling one or more vehicle applications. The testbed can model simulations up to 24 hours. The vehicle performance during simulations can be customized for any required precision by setting a variety of vehicle parameters. The testbed is built from basic principles and is easily upgradable for future expansions or upgrades.<br>Master of Science
41
Valle-Cervantes, Sergio. "Plant-wide monitoring of processes under closed-loop control." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3035991.
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Osinuga, Mobolaji. "Weight optimization in H∞ loop-shaping control and applications." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/weight-optimization-in-hinfinity-loopshaping-control-and-applications(58102c35-9a75-44af-9879-4f142ca4aa09).html.
Full textAbstract:
The primary objective of this thesis is to leverage on the framework of H∞ loop-shaping control to formulate efficient and powerful optimization algorithms in LMI framework for the synthesis of performance loop-shaping weights. The H∞ loop-shaping design procedure is an efficient controller synthesis technique that combines classical loop-shaping concepts with H∞ synthesis. This procedure establishes a good tradeoff between robust stability and robust performance of a closed-loop system in a systematic manner. However, the selection of pre- and/or post-compensators, a crucial step in the design procedure, is nontrivial as factors such as the right half plane poles/zeros of the nominal plant, roll-off rate around the crossover frequency, strength of cross-coupling in multi-input multi-output systems, expected bandwidth, etc. must be adequately considered.Firstly, a frequency-dependent weight optimization framework is formulated in state-space form in order to remove the dependency on frequency while retaining the objective of maximizing the robust stability margin of a closed-loop system. This formulation facilitates the synthesis of low-order controllers, which is desirable from an implementation perspective.A weight optimization framework that incorporates smoothness constraints in order to prevent the cancellation of important modes of the system, for example, lightly damped poles/zeros of flexible structures, is subsequently formulated. The proposed formulation is intuitive from a design perspective as the smoothness constraints are expressed as gradient constraints on a log-log scale in dB/decade, consistent with the notation used in Bode plot for single-input single-output systems and singular value plots for multi-input multi-output systems.Thereafter, an optimization framework that maximizes the robust performance of a closed-loop system is presented. The philosophy in this framework is in line with practical design objectives that give the best achievable robust performance on a particular problem once a level of robust stability margin is demanded.Lastly, a novel unmanned vehicle is proposed. The vehicle uses a full six-degree-of-freedom tri-rotor actuation, capable of fully decoupled thrust and torque vectoring in all the 3D space. This vehicle can act as an unmanned ground vehicle or unmanned aerial vehicle, but the objective herein is restricted to the upright stability of the vehicle while operating on the ground as this is a precursor to rolling motion. The full nonlinear model of the vehicle is derived and linearized for subsequent controller synthesis, and this is thereafter validated by means of numerical simulations.
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Sadati, Seyed Hossein. "Closed loop control of guided missiles using neural networks." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186531.
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An optimal guidance law for a missile flight is one which determines appropriate controls to produce a flight path such that some mission objective will be achieved in the most efficient manner. Optimal Control Theory is often used to accomplish this task. One must bear in mind, however, that the usefulness of optimal control is sharply divided between two distinct classes of dynamical systems, namely, linear systems and nonlinear systems. For linear systems, the theory is complete in the sense that given a quadratic cost, a closed-loop feedback guidance law may be determined. For nonlinear systems, generally the best one can do is to determine an open-loop guidance law numerically using a software package such as MISER (1). (Some notable exceptions exist where a complete analytical synthesis of the closed-loop control may be obtained for nonlinear systems, e.g., in (2).) Although open-loop optimal guidance laws for nonlinear systems can now be computed quite efficiently with the advances of sophisticated numerical techniques along with high-speed digital computers, the highly-nonlinear and complex dynamics of missiles precludes the possibility of on-line implementation of open-loop optimal control. It has always been realized that if optimal closed-loop solutions could be obtained for comprehensive nonlinear systems such as missiles, then guidance laws based on such results would be superior to any other guidance laws available today. This superiority is due to, among other things, the elimination of some of the restrictive, and in many cases unrealistic assumptions made in the derivation of most current guidance laws in use such as, for instance, "tail-chase", unbounded control, simplified dynamics and/or aerodynamics, and non-maneuvering target, to name a few. In this study, an optimal closed-loop control law is obtained off-line by means of a Neural Network which is then used as an on-line controller for a generic missile. In the nonlinear case, the missile/target scenario is set up as a mathematical model using realistic dynamics. Then, given a Performance Index, the open-loop control is obtained by solving the problem using the optimal control software MISER for a number of different initial configurations. These open-loop solutions are then used to "teach" a neural network via backpropagation. Through simulation, it is then demonstrated how well the neural network performs as a feedback controller. The miss distance as well as the value of the Performance Index are used as measures of performance to be compared under the original open-loop control and the neural network closed-loop control. This problem is further extended to include a time lag in the missile dynamics. The effect of this time delay in the overall performance of the optimal controller is then examined.
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Jenne, Theresa Clara. "Closed-loop control of roll bending/twisting : a shape control system for beams." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/35334.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1986.<br>MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING<br>Bibliography: leaves 150-152.<br>by Theresa Clara Jenne.<br>M.S.
45
Luo, F. L. "Digital control of power semiconductor converters." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383314.
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Farenzena, Marcelo. "Novel methodologies for assessment and diagnostics in control loop management." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2008. http://hdl.handle.net/10183/13943.
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Na literatura há vários trabalhos elucidando a importância de ferramentas para auditar malhas de controle. Na indústria, o interesse por esse tipo de software é crescente, devido ao benefício trazido: garantir o exato desempenho para cada controlador significa atingir pontos de operação mais lucrativos. Todavia, as metodologias disponíveis na literatura e nas ferramentas comerciais não provêm medidas conclusivas das características da malha. Conseqüentemente, a análise muitas vezes é confusa e difícil, acarretando um diagnóstico difícil. Reduzir a distância entre a auditoria e o diagnóstico, propondo novas métricas para ajudar o engenheiro no gerenciamento de malhas é o foco central deste trabalho. A presente tese é segmentada em duas partes: auditoria e diagnóstico, dentro das quais se inserem as principais contribuições deste trabalho. A primeira contribuição deste trabalho é a proposição de uma metodologia para decompor o impacto da velocidade do controlador, tempo morto e ruído branco sobre a variância total da malha, auxiliando o engenheiro de processos a tomar uma ação: trocar os parâmetros de ajuste, aumentar a ordem do controlador, substituir o medidor, reduzir o tempo morto, entre outros. O método proposto requer apenas dados de operação normal e o tempo morto da malha, não sendo necessários testes intrusivos, sendo possível a aplicação industrial. O conjunto de métricas propostas foi aplicado em três casos de estudo, fornecendo resultados promissores. Dentro do campo de auditoria, se insere a segunda contribuição: a proposição de uma metodologia para estimação de parâmetros conclusivos (ou determinísticos) para avaliação da performance e robustez de controladores (Máxima Sensibilidade, razão entre o tempo de subida de malha aberta e fechada, razão entre o tempo de assentamento de malha aberta e fechada, entre outros), baseado em índices estocásticos (i.e. métricas que podem ser computadas em tempo real, sem testes intrusivos) e parâmetros da malha (tempo morto, constante de tempo). O modelo de inferência para desempenho e robustez, chamado PRIM, é proposto. Este modelo fornece uma clara indicação do real desempenho e robustez da malha, facilitando a análise e tornando o diagnóstico direto. Além disso, visando elucidar a vantagem dos índices determinísticos sobre os estocásticos, ambos serão aplicados a um conjunto de casos de estudo. A última contribuição no campo de auditoria está na estimação do potencial impacto econômico de cada malha, como ferramenta para hierarquizar sua manutenção. Considerando que uma típica planta química possui centenas ou milhares de malhas e que a maioria delas possui significativo potencial de melhora, a priorização da manutenção é essencial. O impacto econômico é baseado no conceito de Matriz de Variabilidade (VM), que é uma matriz que mostra o impacto da melhora da performance de um controlador sobre a variabilidade de toda a planta. A segunda parte deste trabalho aborda o diagnóstico de algumas avarias comuns em controladores. A primeira metodologia visa quantificar a banda de agarramento em válvulas de controle, que apresentam este fenômeno, através de um modelo de inferência chamado SIM. A metodologia proposta requer apenas dados de operação normal do controlador e planta. A contribuição final deste trabalho é um método simples para avaliação do modelo em controladores preditivos MPCs, baseado na Análise de Componentes Independentes (ICA). Esta análise é bastante útil para indicar os canais que possuem modelo pobre em relação à planta. O trabalho finaliza com as conclusões finais e os trabalhos futuros relativos a esta tese.<br>Many works available in the literature support the importance of control loop performance assessment (CLPA) tools. Industrially, there is an increasing interest in this area and the reason is trivial: ensuring the exact performance for each loop means allowing it to operate in a high profitable operating point. However, the available methodologies in commercial tools and literature do not provide clear and conclusive metrics of the actual loop performance. Consequently, the diagnostics is not easy, making the analysis sometimes difficult and confusing. The aim of this thesis is to reduce the gap between assessment and diagnostics by proposing a set of metrics to help the engineer in control loop performance management. The thesis is divided into two sections: Assessment and Diagnostic. The first contribution of this work is the proposition of a new methodology to decompose the impact of control loop performance, time delay, and white noise in the total control loop variance, helping the engineer to diagnose the loop performance problem and take the right action to achieve the desired product variability (by changing tuning parameters, changing controller type, replacing instrument, or changing the process, among others). The proposed method does not require any invasive tests, only control loop routine operating data and process time delay, allowing the industrial application of the proposed indices in real time. The methodology was applied in three case studies, providing very good results. The second contribution is propose a methodology to estimate conclusive indices (also called deterministic indices) to evaluate loop performance and robustness (maximal sensitivity, ratio between open and closed loop rise time, settling time, among others), based on stochastic indices (i.e. indices that can be computed using only normal operating data) and process parameters (time delay and time constant). A performance and robustness inferential model (PRIM) for loop assessment will be shown. The PRIM provides a clear picture of loop performance and robustness, making the analysis easier and the diagnostics straightforward. Moreover, this section highlights the limitation and drawbacks of stochastic metrics for CLPA. The last contribution of the Assessment section proposes a method to prioritize loop maintenance, based on the economic impact of each loop. Assuming that a typical process plant has hundreds or thousands of loops and most of them have significant impact over loop variability, prioritizing loop maintenance is essential. The economic impact is based on the concept of Variability Matrix (VM), which is an array that shows the impact of performance improvement of a given loop on the whole plant. The second section of this work is the Diagnostics of some controller problems. The first methodology aims to quantify the stickband in a sticky valve, using only normal operating data of controller output and process variable. An analogous inference model, called Stiction Inference Model (SIM), is proposed to estimate the stickband. In the final contribution, it is proposed a simple method to evaluate the Model Plant Mismatch (MPM) based on Independent Component Analysis (ICA). This analysis is very useful to point out the poor channels models in Model Predictive Controllers. The work ends with concluding remarks and further work.
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Wiltse, John Michael. "Control of mixing in a nonreactive plane shear layer: I. Open-loop control. II. Feedback control." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186580.
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A control system for the enhancement and regulation of mixing in a nonreactive plane shear layer has been developed in a two-stream closed-return water facility. Mixing of a passive scalar is estimated using a thermal analog in which the two streams have uniform, steady temperatures differing by 3°C. The position of the temperature interface between the two streams is measured in the plane of its cross stream Schlieren image by an optical sensor which is placed upstream of the rollup of the primary vortices. Control is effected via an array of surface heaters flush-mounted on the flow partition and cross-stream temperature distributions are measured with a resolution of 0.03°C using an array of closely-spaced cold wire sensors. In closed-loop experiments the output from the interface position sensor is fed back to the surface heaters. A transfer function is used to predict the effect of feedback on the interface motion. The dependence of various measures of mixing on the feedback gain k and the total delay time Δ between the actuators and the sensors is studied. The feedback gain k is adaptively modified to maximize mixing at a given streamwise station. These experiments indicate that feedback control of the motion of the temperature interface can be used for controlling the nominally 2D entrainment by the primary vortices and thus enhancing mixing.
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Skillsäter, Calle. "Evaluation and Configuration of a Control Loop Asset Monitoring Tool." Thesis, Linköpings universitet, Reglerteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-67855.
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In this thesis, an automatic control performance monitoring tool is analyzed and evaluated. The tool is called Control Loop Asset Monitor (CLAM) and is a part of the Asset Optimization extension to the ABB platform System 800xA. CLAM calculates and combines a number of performance indices into diagnoses. The functionality, choice of configuration parameters and the quality of the result from CLAM have been analyzed using data from the pulp mill Södra Cell Mörrum. In order to get reliable diagnoses from CLAM, it is important that it is correctly configured. It was found that some of the default parameters should be modified and the recommendations in the user guidelines should be updated. Using the current default parameters, there are some combinations of indices that never can exceed defined alarm severity thresholds. The conclusions in this thesis have been documented in an online help that also includes simple user instructions for how the results from CLAM should be interpreted. The results have been analyzed together with the staff at Södra Cell Mörrum in order to validate that they are correct and relevant from a user perspective. It was found that the results are correct, but there are some things that can be improved in order to make CLAM more user friendly.
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Chipalkatty, Rahul. "Human-in-the-loop control for cooperative human-robot tasks." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43649.
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Even with the advance of autonomous robotics and automation, many automated tasks still require human intervention or guidance to mediate uncertainties in the environment or to execute the complexities of a task that autonomous robots are not yet equipped to handle. As such, robot controllers are needed that utilize the strengths of both autonomous agents, adept at handling lower level control tasks, and humans, superior at handling higher-level cognitive tasks.
To address this need, we develop a control theoretic framework that seeks to incorporate user commands such that user intention is preserved while an automated task is carried out by the controller. This is a novel approach in that system theoretic tools allow for analytic guarantees of feasibility and convergence to goal states which naturally lead to varying levels of autonomy. We develop a model predictive controller that takes human input, infers human intent, then applies a control that minimizes deviations from the intended human control while ensuring that the lower-level automated task is being completed.
This control framework is then evaluated in a human operator study involving a shared control task with human guidance of a mobile robot for navigation. These theoretical and experimental results lay the foundation for applying this control method for human-robot cooperative control to actual human-robot tasks. Specifically, the control is applied to a Urban Search and Rescue robot task where the shared control of a quadruped rescue robot is needed to ensure static stability during human-guided leg placements in uneven terrain. This control framework is also extended to a multiple user and multiple agent system where the human operators control multiple agents such that the agents maintain a formation while allowing the human operators to manipulate the shape of the formation. User studies are also conducted to evaluate the control in multiple operator scenarios.
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BOSSIO, CARLOS ERNESTO HILBURG. "MINIMAL TIME LOOP CONTROL OF A PERMANENT MAGNET STEP MOTOR WITH THE USE OS AN INNER LOOP." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1986. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9618@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR<br>Descreve-se o controle em malha fechada por malha pequena
de um motor de passo de imã permanente (MIPIP), de forma a
obter posicionamento preciso em tempo mínimo. A malha
pequena é utilizada para, aplicar o modo de controle de
alta velocidade (HISPEED); consegue-se dessa forma atingir
velocidades muito superiores às obtidas em malha aberta. O
principio de controle adotado pelo controlador de malha
externa baseia-se na utilização de tabelas que possuam
dados sobre as curvas de aceleração e desaceleração do
MPIP. Dependendo do número de passos que faltam para
atingir o alvo e da velocidade de rotação do eixo, as
tabelas indicarão o modo de controle adequado de forma a
não ultrapassar o alvo e atingi-lo em tempo mínimo. Um
microcomputador implementa o controlador da malha externa
e indica ao controle da malha interna o modo de operação
adequado.<br>This work describes the use of an inner loop for closed
loop control of a permanent magnet step motor to achieve
precise positioning in minimal time. The inner loop is
used to apply a high speed control; this method gives
speeds higher than those obtained with the open loop
control. The outer loop controller is based on the use of
acceleration and deceleration data of the motor. Depending
on the number of steps needed to reach the desired
position, and the actual speed, these tables indicate the
best control mode to get to the target in minimal time and
without overshooting it. This controller is implemented in
a microcomputer.