Denna studie behandlar controllern och dess roll. Då controllerrollen upplevs som väldigt diffus är syftet att förtydliga vad en controller är genom att använda begreppen bönräknare och företagspartner. Den teoretiska referensramen tar upp teorier från centrala författare inom området, bland annat Lindvall, Mattsson, Frenckner och Samuelson. Studien är en kvalitativ studie och utfördes på Saab AB i Arboga. Totalt åtta stycken djupintervjuer genomfördes med både controllers och icke-controllers för att på detta sätt kunna få en djupare förståelse för controllerrollen. Urvalet av de åtta intervjupersonerna är ett icke-sannolikhetsurval i form av ett bekvämlighetsurval och även ett snöbollsurval. Vid intervjutillfällena användes semistrukturerade intervjuer med en intervjuguide. Detta för att ha friheten att kunna anpassa intervjuerna utifrån de olika personerna som intervjuades och på det sättet kunna fokusera på det de enskilda personerna tyckte var intressant. Genomgående i studien behandlas följande områden: definition, utbildning, egenskaper, arbetsuppgifter, förändringar i omvärlden och framtiden för controllern. Resultatet av vår studie visar att företagspartnerrollen och bönräknarrollen till viss del finns, men att även en ytterligare roll verkar infinna sig, en så kallad kompetensrelationsroll. / This study discusses the controller and its role. Since the role of the controller is perceived as very diffuse, the study aims to clarify what a controller is by using the concepts bean counter and business partner. The theoretical framework discusses theories from key writers in the area, including Lindvall, Mattsson, Frenckner and Samuelson. The study is a qualitative study and was conducted at Saab AB in Arboga. A total of eight interviews were conducted with both controllers and non-controllers to gain a deeper understanding of the role of the controller. The selection of the eight interviewees is a non-probability sample in the form of a convenience sample and it is also a snowball sampling. During the interview sessions we used semi-structured interviews with an interview guide. This way we had the freedom to customize the interviews according to the people interviewed and thus we were able to focus on what the individuals thought was interesting. Throughout the study, the following areas are addressed: the definition, education, personality traits, tasks, changes in the surrounding world and the future of the controller. The results of our study show that the business partner role and the bean counter role both still exist, but also an additional role seems to appear, a so-called competence relationship.

This thesis deals with enhancing the performance of Fuzzy Logic (FL) based PI controllers for High Voltage Direct Current Transmission Systems (HVDC) by optimizing the key parameters i.e. membership functions (MFs) and fuzzy rule base in the controllers design. In the first part of the thesis, an adaptive Fuzzy PI controller is designed and the effect of various MF shapes, widths and distribution on the performance of a FL controlled HVDC system under different system conditions is studied with the aim of selecting a MF which minimizes the total control error. Simulated results show that the shape, width and distribution of a MF influences the performance of the FL controller and concludes that nonlinear MFs (i.e. Gaussian) offer a more better choice than linear (i.e. Triangular) MFs as the former provides a smoother transition at the switching points and thus propose a better controller. In the second part of the thesis, a Neuro-Fuzzy (NF) controller to update the fuzzy rule base with changing system conditions is proposed, which in turn adjusts the PI gains of a conventional PI controller. Results from simulations illustrate the potential of the proposed control scheme as the NF controller successfully adapts to different system conditions and is able to minimize the total current error. / UOIT

Based on the Lypunov stability theorem, a design methodology of adaptive backstepping control is proposed in this thesis for a class of multi-input systems with matched and mismatched perturbations to solve regulation problems. The systems to be controlled contain blocks¡¦ dynamic equations, hence virtual input controllers are firstly designed so that the state variables of first blocks are asymptotically stable if each virtual control input is equal to the state variable of next block. The control input is designed in the last block to ensure asymptotic stability for each state even if the perturbations exist. In addition, adaptive mechanisms are embedded in each virtual input function and control input, so that the upper bound of perturbations is not required to be known beforehand. Finally, a numerical example and a practical application are given for demonstrating the feasibility of the proposed control scheme. ­^¤åºK­n(keyword)¡Gadaptive block backstepping controller, mismatched parameter uncertainty, virtual input controller, Lyapunov stability .

As time goes by rapid development of 3D graphics technique and 3C portable product output, 3D graphics have been widely applied to handheld devices, such as notebooks, PDAs, and smart cellular phones. Generally, to process 3D graphics applications in mobile devices, processor needs strong capability of handling large computational-intensive workloads. Complex computation consumes a great quantity of electric power. But the lifetime of handheld device battery is limited. Therefore, the cost, to satisfy this demand, will be shortening the supply time of device battery. Moreover, Moore¡¦ law said that the number of transistors in a chip is double in every eighteen months. But these days the advance in manufacturing batteries still cannot get up with the advance in developing processors. In addition, the improvement of chip size has led to more small, supply voltage of kernel processor in portable device. Considering system efficiency and battery lifetime simultaneously increase the difficulty of designing power management scheme. So, how to manage power effectively has become one of the important key for designing handheld products. For 3D graphics system, dynamic voltage and frequency scaling (DVFS) is one of good solutions to implement power management policy. DVFS needs an efficient online prediction method to predict the workload of frames and then appropriately adjust voltage and frequency for saving energy consumption. Consequently, a lot of related papers have proposed different prediction policy to predict the executing workload of 3D graphics system. For instance, the existing prediction policies include signature-based[1], history-based[3] and proportion-integral-derivative (PID)[14] methods, but most of designers put power management in software, i.e. processors. This solution not only slows power management to get the information about executing time of graphic processing unit (GPU), but also increases the operating overhead of CPU in handheld system. In this paper, we propose a power management workload prediction scheme with a framework of using proportion-integral (PI) controller to be a master controller and fuzzy controller to be a slave controller, and then implement it into hardware circuit. Taking advantage of fuzzy conception in fuzzy controller is to adjust the proportional parameter in PI controller, the shortage of traditional PI controller that demands on complicated try-and-error method to look for a good proportional and integral parameters can be avoided so that the adaption and forecasting accuracy can be improved. Besides, Uniform Window-size Predictor 1 (UW1) is also implemented as an assistant manner. Using UW1 predictor appropriately can improve the prediction trend to catch up with the trend of real workload. Experimental results show that our predictor improves prediction accuracy about 3.8% on average and saves about 0.02% more energy compared with PI predictor[18]. Circuit area and power consumption only increases 6.8% percent and 1.4% compared with PI predictor. Besides, we also apply our predictor to the 3D first person game, Quake II, in the market. The result shows that our predictor is indeed an effective prediction policy. The adaption can put up with the intense workload variation of real game and adjust voltage and frequency precisely to decrease power consumption and meet the purpose of energy saving.

This thesis is about the improved design of small size brushless DC fan motor driving circuit. Two main improvements in the new design are increase the stability and decrease the size of motor fan at the same time. To improve the stability, there are two major parts added to the original driving circuit. The delay circuit that protects the H-bridge and the output low current limit circuit. Furthermore, it is believed that the speed control also can improve the stability. With regard to the rotation speed control, two circuits are attached to the motor, 1) speed feedback controller and 2) speed and current feedback controller. Both controllers are attached in the close loop rotation speed control circuit. They are used to increase the efficiency of drive circuit. In order to make the circuit more efficient, they solve problems such as disturbance in miscellaneous noise; also the power dissipation that occurs in open loop rotation speed control circuit. The second improvement in the new design is to reduce the cost and size of system. The design of sensorless control scheme is proposed to replace the Hall sensor to detect rotor position. This sensorless scheme can also supply fan motor voltage to achieve the speed control.

Based on the Lyapunov stability theorem, a decentralized adaptive backstepping tracking control scheme for a class of perturbed large-scale systems with non-strict feedback form is presented in this thesis to solve tracking problems. First of all, the dynamic equations of the plant to be controlled are transformed into other equations with semi-strict feedback form. Then a decentralized tracking controller is designed based on the backstepping control methodology so that the outputs of controlled system are capable of tracking the desired signals generated from a reference model. In addition, by utilizing adaptive mechanisms embedded in the backstepping controller, one need not acquire the upper bounds of the perturbations and the interconnections in advance. The resultant control scheme is able to guarantee the stability of the whole large-scale systems, and the tracking precision may be adjusted through the design parameters. Finally, one numerical and one practical examples are demonstrated for showing the applicability of the proposed design technique.

This study describes the design and implementation of the pitch and roll autopilots for a fixed wing unmanned vehicle. A Tactical Unmanned Aerial Vehicle (TUAV), which is designed at the Middle East Technical University (METU), is used as a platform. This work combines development of the classical and robust controllers, which are used for the pitch and roll autopilots. One of the important steps in the thesis is development of the non-linear dynamic model of the UAV, which is developed in MATLAB/Simulink environment. Two different strategies of the controller design imply development of the PID and controllers. Simulation results illustrate the performances of the designed controllers. Simulation is performed for the nominal model of the UAV and for the model that includes uncertainties and sensor noises.

In this study, the use of modified genetic algorithms (MGA) in the parameterization of the Transmission Mechanisms is facilitated. The new algorithm is proposed from the genetic algorithm with some additional strategies, and yields a faster convergence and a more accurate search. Firstly, this near-optimum search technique, MGA-based ID method, is used to identify the parameters of a system described by an ARMAX model in the presence of white noise and to compare with the LMS (Least mean-squares) method and GA method. Then, this proposed algorithm is applied to the identification of the Transmission Mechanisms of DC motor. The parameters of the friction force and DC motor are estimated in a single identification experiment. It is also shown that this technique is capable of identifying the whole transmission system. Finally, the Minimum Variance Controller (MVC) is taken to track the desired speed trajectory and then a comparison to the conventional digital PID controller is shown. Experiment results are included to demonstrate the excellent performance of the MVC.

By means of fuzzy set theory as well as Takagi-Sugeno and Mamdani fuzzy controller, this paper presents the investigation of a Resort Management System implemented by a combination of a T-S model and a Mamdani model. It demonstrates the procedure of the specific premise parameters identification and consequence parameters identification performed by regression knowledge in the T-S model, and the process of the fuzzification, the rule base creation and the defuzzification with COG technique in the Mamdani model. Therefore, an aggregation between T-S controller and Mamdani controller applied in the field of management by a novel angle is illustrated, which, as a result, devotes an improved management system that shares great convenience in the control process when combined with mathematics. Moreover, a modification of the conventional Takagi-Sugeno and Mamdani controller is demonstrated in conjunction with fuzzy operations t-norms and OWA by adjusting the -value, which is used in the calculation of final outputs in the T-S model and the computation of rule consequences in the Mamdani model. The algebraic intersection, bounded intersection as well as the -parameter t-norm are the t-norms which are going to be introduced. Besides, we have tested that t-norms generate the same alpha values when the membership degrees meet the boundary with the value of 1 or 0 while OWA can still yield a well-balanced result different from the one computing by minimum operation. Nevertheless both t-norms and OWA are able to shift the alpha-value in a well-adjusted way when the membership degrees lie in the interval [0,1]. A tendency has been shown that alpha-value tends to decrease by means of t-norms and OWA operations and consequently, the final outputs appear to be reduced.

Two application applications of Fuzzy Logic to improve the performance of two controllers are presented. The first application takes a Sliding Mode Controller designed for chemical process to reject disturbances. A fuzzy element is added to the sliding surface to improve the controller performance when set point change affects the control loop; especially for process showing highly nonlinear behavior. This fuzzy element, , is calculated by means of a set of fuzzy rules designed based on expert knowledge and experience. The addition of improved the controller response because accelerate or smooth the controller as the control loop requires. The Fuzzy Sliding Mode Controller (FSMCr) is a completely general controller. The FSMCr was tested with two models of nonlinear process: mixing tank and neutralization reactor. In both cases the FSMCr improves the performance shown for other control strategies, as the industrial PID, the conventional Sliding Mode Control and the Stan dard Fuzzy Logic Controller. The second part of this research presents a new way to implement the Dynamic Matrix Control Algorithm (DMC). A Parametric structure of DMC (PDMC) control algorithm is proposed, allowing to the controller to adapt to process nonlinearities. For a standard DMC a process model is used to calculate de controller response. This model is a matrix calculated from the dynamic response of the process at open loop. In this case the process parameters are imbibed into the matrix. The parametric structure isolates the process parameters allowing adjust the model as the nonlinear process changes its behavior. A Fuzzy supervisor was developed to detect changes in the process and send taht [sic]information to the PDMCr. The modeling error and other parameters related were used to estimate those changes. Some equations were developed to calculate the PDMCr tuning parameter,lambda, as a function of the process parameters. The performance of PDMCr was tested using to model of nonlinear process and compare with the standard DMC; in most the cases PDMCr presents less oscillations and tracks with less error the set point. Both control strategies presented in this research can be implemented into industrial applications easily.