Coordinated or synchronized tasks can always be found in various manufacturing processes, e.g., machining along spatial trajectories, coordinated operations of multi-manipulators, and vacuum pumps, etc. The vacuum pump is a typical device with synchronized motion among those examples. The vacuum pump has played an important role in current semiconductor manufacturing processes. Its pumping feature is achieved by synchronized motion of two mating pump rotors. A common approach to accomplish the synchronized motion is by idle gears. Nevertheless, this design cannot meet serious requirements of vacuum systems demanded by growing manufacturing techniques. In order to provide a complete and proper control strategy for synchronized motion, and to overthrow traditional architecture of vacuum pumps by raising a better control scheme for new generation oil-less products, the paper focuses on synchronized motion control for dual motors. The first objective of here is to develop a control method for synchronized motion of two separated motors. Both system uncertainties and unknown disturbances occurring in actual implementation need to be carefully considered. An experimental setup will also be established for examinations and verifications. And then synchronized motion control of dual motors including two mating screw rotors then will be investigated. During this period, the emphasis will be on solution finding for unexpected contact collision between two rotors. An effective and efficient control strategy will be developed for synchronized motion control of dual motors. Longer operation time and better synchronization performance for two motors can therefore be anticipated.

Abstract Coordinated or synchronized tasks can always be found in various manufacturing processes, e.g., machining along spatial trajectories, coordinated operations of multi-manipulators, and vacuum pumps, etc. The vacuum pump is a typical device with synchronized motion among those examples. The vacuum pump has played an important role in current semiconductor manufacturing processes. Its pumping feature is achieved by synchronized motion of two mating pump rotors. A common approach to accomplish the synchronized motion is by idle gears. Nevertheless, this design cannot meet serious requirements of vacuum systems demanded by growing manufacturing techniques. In order to provide a complete and proper control strategy for synchronized motion, and to overthrow traditional architecture of vacuum pumps by raising a better control scheme for new generation oil-less products, the paper focuses on synchronized motion control for dual motors. The first objective of here is to develop a control method for synchronized motion of two separated motors. Both system uncertainties and unknown disturbances occurring in actual implementation need to be carefully considered. An experimental setup will also be established for examinations and verifications. And then synchronized motion control of dual motors including two mating screw rotors then will be investigated. During this period, the emphasis will be on solution finding for unexpected contact collision between two rotors. An effective and efficient control strategy will be developed for synchronized motion control of dual motors. Longer operation time and better synchronization performance for two motors can therefore be anticipated.

Modern technologies coupled with advanced research have allowed model predictive control (MPC) to be applied to new and often experimental systems. The purpose of this research is to develop a model predictive control algorithm for tip-jet reaction drive system. This system's faster dynamics require an extremely short sampling rate, on the order of 20ms, and its slower dynamics require a longer prediction horizon. This coupled with the fact that the tip-jet reaction drive system has multiple control inputs makes the integration of an online MPC algorithm challenging. In order to apply a model predictive control to the system in question, an algorithm is proposed that combines multiplexed inputs and a feasible cooperative MPC algorithm. In the proposed algorithm, it is hypothesized that the computational burden will be reduced from approximately Hp(Nu + Nx)3 to pHp(Nx+1)3 while maintaining control performance similar to that of a centralized MPC algorithm. To capture the performance capability of the proposed controller, a comparison its performance to that of a multivariable proportional-integral (PI) controller and a centralized MPC is executed. The sensitivity of the proposed MPC to various design variables is also explored. In terms of bandwidth, interactions, and disturbance rejection, the proposed MPC was very similar to that of a centralized MPC or PI controller. Additionally in regards to sensitivity to modeling error, there is not a noticeable difference between the two MPC controllers. Although the constraints are handled adequately for the proposed controller, adjustments can be made in the design and sizing process to improve the constraint handling, so that it is more comparable to that of the centralized MPC. Given these observations, the hypothesis of the dissertation has been confirmed. The proposed MPC does in fact reduce computational burden while maintaining close to centralized MPC performance.

La plaga Spodoptera frugiperda (Lepidopteroa: Noctuidae), es una especie polífaga que se encuentra difundida en todos los países americanos, provocando grandes pérdidas en los rendimientos de varios cultivos. La plaga Aphis craccivora causa daños a los cultivos anuales como alfalfa, habas, alcachofa, tomate y otros, al alimentarse de la savia, provoca deformaciones en los brotes tiernos y enrollamiento de las hojas y la muerte de la planta; asimismo, secreta una mielecilla que favorece el desarrollo de especies de hongos causantes de fumagina, afectando la fotosíntesis de la planta. Dentro de las alternativas de control con bajo impacto ambiental, se realizó la investigación para evaluar la susceptibilidad de estas dos plagas a la cepa Beauveria bassiana CBLE-265, producida por el Servicio Nacional de Sanidad Agraria (SENASA), con la finalidad de determinar la concentración letal al 50 % (CL50) y la concentración letal al 90 % (CL90) de la cepa frente a la plaga Spodoptera frugiperda y la plaga Aphis craccivora. Para definir las concentraciones se tuvo como base la dosis comercial del producto. Para la inoculación se asperjaron soluciones en diferentes concentraciones de Beauveria bassiana CBLE-265 con atomizadores manuales, a las larvas del I, II, y III estadío de Spodoptera frugiperda, después se colocaron en rejillas acrílicas con dieta artificial para su evaluación, mientras que para Aphis craccivora se asperjaron a las ninfas que estaban en maceteros con alfalfa para su evaluación. Utilizando el programa Probit se analizaron los datos de mortalidad del bioensayo a partir del 5to día hasta que lleguen a la etapa adulta, determinándose mediante proyecciones la concentración letal media y la concentración letal noventa. Para Spodoptera frugiperda estadío I, el valor del CL50 fue de 1,90 x 1024 conidias/g y el valor del CL90 fue de 2,30 x 1031 conidias/g, para estadío II, el valor del CL50 fue de 7,90 x 1024 conidias/g y el valor del CL90 fue de 9,10 x 1031 conidias/g. Para el estadio III, no se encontró letalidad con la cepa estudiada. Así como para las ninfas de Aphis craccivora no tuvo efecto alguno la cepa estudiada, por lo que se concluye que la cepa Beauveria bassiana CBLE-265 no es adecuada para el control de Plaga como Aphis Craccivora, no teniendo un efecto significativo. / The plague Spodoptera frugiperda (Lepidopteroa: Noctuidae), is a polyphagous species that is widespread throughout in all Americans countries, causing great losses in yields of several crops. The plague Aphis craccivora cause damage to the annual crops as alfalfa, beans, artichoke, tomato and others, by feeding on sap, causing deformations in the buds and the leaves curl and the death of the plant; also, excreted a honeydew that encourages the development of species of fungi causing fumagin, affecting the photosynthesis of the plant. Among the control alternatives with lower environmental impact, research was conducted to evaluate the susceptibility of these two plagues at the strain Beauveria bassiana CBLE-265, produced by the National Service of Agrarian Health (SENASA), in order to determine the LC50 and LC90 of the strain against the plague Spodoptera frugiperda and the plague Aphis craccivora. To define the concentrations was based on the commercial dose of the product. For inoculation were sprayed solutions at different concentrations of Beauveria bassiana CBLE-265 with manual spray to the larva of I, II and III stage of Spodoptera frugiperda, then placed in acrylic racks with artificial diet for its evaluation, whereas Aphis craccivora were sprayed at the nymphs, were in pots with alfalfa for its evaluation. Using the Probit program were analyzed mortality data from bioassay of the 5th day until they reach the adult stage, determined through projections the median lethal concentration and lethal concentration ninety. For stage I of Spodoptera frugiperda, the value of LC50 was 1,90 x 1024 conidia/g and the value of LC90 was 2,30 x 1031 conidia/g, for stage II, the value of LC50 was 7,90 x 1024 conidia/g and the value of LC90 was 9,10 x 1031 conidia/g. While for the nymphs of Aphis craccivora had no effect of the strain studied, so it is concluded that the strain of Beauveria bassiana CBLE-265 is not adequate to control both plagues, not having a significant effect.

Die vorliegende Arbeit widmet sich der, vorwiegend experimentellen, Untersuchung der Wirkung wandparalleler Lorentzkräfte in Strömungsrichtung auf Grenzschichtprofile und Körperumströmungen. Die Themen - Beeinflussung der Grenzschicht an ebenen Platten mit stationären Lorentzkräften - Kontrolle von Strömungsablösungen an Zylindern und symmetrischen Profilen mit stationären Lorentzkräften - Beeinflussung von Zylindernachläufen und abgelösten Tragflügelumströmungen mit zeitlich periodischen Lorentzkräften werden behandelt.

Thesis (Ph. D.)--School of Industrial and Systems Engineering, Georgia Institute of Technology, 2004. Directed by Paul H. Kvam. / Vita. Includes bibliographical references (leaves 108-113).

Includes bibliographical references (p. 121-124).

The existing powertrain control system in Volvo CE's vehicles consists of various types of physical quantities that are controlled. One of them is the engine speed. The purpose of this thesis is to investigate whether there are other control strategies suitable for engine speed control, than the existing one. Currently, the existing control system requires re-calibration of the control parameters if hardware in the vehicle is replaced. The current controller is a gain-scheduled PID controller with control parameters that varies over the operating range. The aim has been to develop several different adaptive control strategies. Adaptive control methods are expected to adapt to the changes of the system that a replacement of hardware can bring. The performance and robustness of the developed controllers have been compared with the existing controller. The approach has been to implement the control strategies in Matlab/Simulink and simulate the process with existing engine software provided by Volvo CE. The next step was to test and verify the controllers in a real machine. The focus in this thesis work has been on the adaptive control strategies MRAC (Model-Reference Adaptive Control) and L1 Adaptive Control. In the MRAC structure the desired performance is specified in terms of a reference model that the real system is supposed to follow. Each time an error is generated, by comparing actual and desired output, a suitable algorithm is used in order to obtain the control signal that can minimize the error. In addition, modeling errors and disturbances are estimated so that the controller can compensate for these. L1 Adaptive Control is an extension of the MRAC structure. The difference is that before the control signal is fed to the real system, it is low-pass filtered. This is done in order to prevent feeding high frequencies into the system. The results show that adaptive control has potential to be used in engine speed control. Reference following and disturbance rejection is well handled and simulations have furthermore shown that the developed controllers can deal with changes in the hardware. One of the developed L1-controllers was implemented in a real machine with promising results. / Det existerande styrsystemet i Volvo CE:s maskiner har till uppgift att styra och reglera flera olika fysikaliska storheter. En av dessa storheter är motorvarvtalet. Syftet med detta examensarbete är att undersöka alternativa reglerstrategier som kan användas för att styra motorvarvtalet. Problemet idag är att det nuvarande styrsystemet kräver omkalibrering av regulatorparametrar när befintlig hårdvara i maskinen behöver ersättas på grund av föråldring eller slitage. Den nuvarande regulatorn är en parameterstyrd PID-regulator där regulatorparametrarna beror av aktuell arbetspunkt. Målet har varit att utveckla och prova flera olika adaptiva reglerstrategier. Dessa metoder förväntas kunna hantera förändringar och adaptera sig mot nya förhållanden och omständigheter som en hårdvaruförändring kan medföra. Prestanda och robusthet som de utvecklade regulatorerna erhåller har jämförts mot den existerande regulatorstrukturen. Tillvägagångssättet har varit att implementera reglerstrategierna i Matlab/Simulink samt simulera med tillhörande motormjukvara som Volvo CE tillhandahållit. I nästa fas skulle regulatorerna testas och verifieras i en riktig maskin. Fokuset har under detta examensarbete riktats mot de två adaptiva reglerstrategierna Model-Reference Adaptive Control (MRAC) och L1 Adaptive Control. MRAC-strukturen bygger på att specificera prestandan genom en referens-modell som det riktiga systemet skall följa. Varje gång en avvikelse uppstår så beräknas en lämplig styrsignal genom att beakta och försöka minimera skillnaden mellan det riktiga systemet och den önskade referens-modellen. Till detta modelleras och skattas störningar som regulatorn skall kompensera för. Tekniken inom L1 Adaptive Control är en utvidgning av MRAC. Önskat beteende specificeras även för denna regulatorstruktur men största skillnaden är att innan styrsignalen matas in till systemet så lågpassfiltreras den. Detta görs i förebyggande syfte för att inte släppa in onödigt höga frekvenser in i systemet. Resultaten visar att adaptiv reglering av motorvarvtalet har potential. Referensföljning och undertryckning av störningar hanteras väl och simuleringar har dessutom visat att de utvecklade regulatorerna kan hantera hårdvaruändringar. En av de utvecklade L1-regulatorerna implementerades i en riktig maskin och resultaten såg lovande ut.

Three isolates of Curvularia belonging to Curvularia tuberculata (isolates 93-020 and 93-022) and Curvularia oryzae (isolate 93-061) were obtained from diseased Cyperus difformis, Cyperus iria, and Fimbristylis miliacea, respectively, in the Philippines in 1993. Under greenhouse conditions, these fungal isolates caused high mortality and significant plant dry weight reduction in C. difformis, C. iria, and F. miliacea when sprayed at the rate of 1 x 108 spores/m3. Cross-pathogenicity of the isolates was demonstrated in three other sedge weed species. C. difformis, C. iria, and F. miliacea were killed but C. rotundus was resistant. Most of the thirteen rice varieties tested were resistant to the fungal isolates. The order of decreasing pathogenicity to rice was C. oryzae (93-061), C. tuberculata (93-020), and C. tuberculata (93-022). The infection process of C. tuberculata and C. oryzae was similar. Spore germination was polar for C. tuberculata and bipolar for C. oryzae. Germ tube growth was random and branching. Appressoria were formed preferentially over epidermal cell wall junctions on sedge hosts and over stomatal apertures in rice. Complex infection cushions were observed only on sedge hosts. Infection hyphae developed inter- and intracellularly, causing epidermal cell walls to separate and mesophyll cells to shrink and collapse. The vascular bundles were not invaded. Colonization of susceptible weeds was rapid and conidiophores emerged from the stomatal aperture between 96 to 120 hours post inoculation (HPI). Resistance to C. tuberculata and C. oryzae in C. rotundus and rice was expressed as a delay in appressorial formation, inhibition of fungal growth after penetration, and lack of sporulation.

This work focuses on the robustness issues related to distributed model predictive control (DMPC) strategies in the presence of model uncertainty. The robustness of DMPC with respect to model uncertainty has been identified by researchers as a key factor in the successful application of DMPC. A first task towards the formulation of robust DMPC strategy was to propose a new systematic methodology for the selection of a control structure in the context of DMPC. The methodology is based on the trade-off between performance and simplicity of structure (e.g., a centralized versus decentralized structure) and is formulated as a multi-objective mixed-integer nonlinear program (MINLP). The multi-objective function is composed of the contribution of two indices: 1) closed-loop performance index computed as an upper bound on the variability of the closed-loop system due to the effect on the output error of either set-point or disturbance input, and 2) a connectivity index used as a measure of the simplicity of the control structure. The parametric uncertainty in the models of the process is also considered in the methodology and it is described by a polytopic representation whereby the actual process’s states are assumed to evolve within a polytope whose vertices are defined by linear models that can be obtained from either linearizing a nonlinear model or from their identification in the neighborhood of different operating conditions. The system’s closed-loop performance and stability are formulated as Linear Matrix Inequalities (LMI) problems so that efficient interior-point methods can be exploited. To solve the MINLP a multi-start approach is adopted in which many starting points are generated in an attempt to obtain global optima. The efficiency of the proposed methodology is shown through its application to benchmark simulation examples. The simulation results are consistent with the conclusions obtained from the analysis. The proposed methodology can be applied at the design stage to select the best control configuration in the presence of model errors. A second goal accomplished in this research was the development of a novel online algorithm for robust DMPC that explicitly accounts for parametric uncertainty in the model. This algorithm requires the decomposition of the entire system’s model into N subsystems and the solution of N convex corresponding optimization problems in parallel. The objective of this parallel optimizations is to minimize an upper bound on a robust performance objective by using a time-varying state-feedback controller for each subsystem. Model uncertainty is explicitly considered through the use of polytopic description of the model. The algorithm employs an LMI approach, in which the solutions are convex and obtained in polynomial time. An observer is designed and embedded within each controller to perform state estimations and the stability of the observer integrated with the controller is tested online via LMI conditions. An iterative design method is also proposed for computing the observer gain. This algorithm has many practical advantages, the first of which is the fact that it can be implemented in real-time control applications and thus has the benefit of enabling the use of a decentralized structure while maintaining overall stability and improving the performance of the system. It has been shown that the proposed algorithm can achieve the theoretical performance of centralized control. Furthermore, the proposed algorithm can be formulated using a variety of objectives, such as Nash equilibrium, involving interacting processing units with local objective functions or fully decentralized control in the case of communication failure. Such cases are commonly encountered in the process industry. Simulations examples are considered to illustrate the application of the proposed method. Finally, a third goal was the formulation of a new algorithm to improve the online computational efficiency of DMPC algorithms. The closed-loop dual-mode paradigm was employed in order to perform most of the heavy computations offline using convex optimization to enlarge invariant sets thus rendering the iterative online solution more efficient. The solution requires the satisfaction of only relatively simple constraints and the solution of problems each involving a small number of decision variables. The algorithm requires solving N convex LMI problems in parallel when cooperative scheme is implemented. The option of using Nash scheme formulation is also available for this algorithm. A relaxation method was incorporated with the algorithm to satisfy initial feasibility by introducing slack variables that converge to zero quickly after a small number of early iterations. Simulation case studies have illustrated the applicability of this approach and have demonstrated that significant improvement can be achieved with respect to computation times. Extensions of the current work in the future should address issues of communication loss, delays and actuator failure and their impact on the robustness of DMPC algorithms. In addition, integration of the proposed DMPC algorithms with other layers in automation hierarchy can be an interesting topic for future work.