A line-follower is a robot that follows a line. Line-followers can be used in industry, mostly for material transportation, but are also raced against each other in competitions. While line-followers used in industry prioritize smooth motion and accuracy, competition-style line-followers prioritize speed around the track. In order for a line-follower to perform well, it needs a robust control-algorithm. Usually, competition-style line-followers use a manually tuned PID-algorithm for control. Tuning a PID-controller can be difficult, and is dependent on the skill of the tuner. There are, however, multiple so called ”heuristic” tuning methods that can give more consistent results, quickly. In this work, some popular heuristic tuning methods have been investigated for control of a competition-style line-follower. The methods have been compared in terms of step-responses and cumulative deviation of the robot from a track. The results indicate that the purely proportional variant of the Ziegler-Nichols method gives the best performance for competition-style line-followers. The ”some overshoot” variant of the modified Ziegler-Nichols method gave the most consistent and accurate results, and could be appropriate for use in an industrial-scale line-follower. Surprisingly the newest method tested, the Tyreus-Luyben technique, had a very unstable behaviour, and have thus been excluded from multiple tests. / En av de enklaste typer av själkörande fordon är en linjeföljande robot. Dessa kan användas i industrin, som materialtransportörer, men också i tävlingar där den snabbaste vinner. För att en linjeföljare ska prestera väl så krävs en robust kontrollalgoritm. De flesta tävlingsinriktade linjeföljare använder sig av en manuellt inställd PID-algoritm. Att manuellt ställa in en kontroller kan dock vara svårt, och kan ge inkonsekventa resultat. För att snabbt ställa in en kontrollalgoritm, med goda och konsekventa resultat, finns det ett flertal så kallade ”heuristiska” metoder. I det här arbetet har några heuristiska metoder använts för att kontrollera en liten linjeföljare. Metoderna har sedan utvärderats utifrån stegsvar och den totala avvikelsen från en bana under en körning. För en liten linjeföljare så gav den rent proportionella varianten av Ziegler-Nichols-metoden bäst prestanda. ”Som eovershoot” varianten av den modifierade Ziegler-Nichols metoden hade dock det jämnaste och mest konsekventa resultatet, och lämpar sig antagligen bäst för en industriell linjeföljare. Förvånande nog så gav den nyaste metoden, Tyreus-Luyben, absolut sämst resultat, och kunde i många fall inte ens testas utan att roboten spårade ur.

Directors designed for observation and fire control in naval environments consist of a mechanical pedestal moved by two electrical motors. To meet the high demands on director precision, a servo solution based on feedback control is used. The digital servo controller has to be tuned to meet demands on performance and stability. This report presents methods for automatic tuning, intended to replace today’s manual tuning procedures. System identification based on relay feedback and recursive least-squares approximations are combined with the Ziegler-Nichols and AMIGO tuning procedures for PI controllers are evaluated. Evaluations are performed in simulations, for which a SIMULINK model is constructed. Results indicate that the automatic tuning may perform well compared to the manual tuning used today, and that it could bring considerable reduction in the time required for tuning.

I detta arbeta gjordes en undersökning om hur en drönare kan regleras vid olika viktbelastningar. Först gjordes en teoretisk undersökning av fyra olika reglermetoder, två modellbaserade och två icke-modellbaserade metoder. De två modellbaserade var linjär kvadratisk reglering och modell prediktiv kontroll. De två icke-modellbaserade var kaskad kontroll och PID regulator. Av alla metoderna valdes det att användas en PID regulator för regleringen. För att ställa in PID testades tre olika metoder, Ziegler-Nichols, lambda och AMIGO metoden. Alla dessa tre använde stegsvaret för systemet för att beräkna parametrarna till PID. Detta resulterade i flera olika parameterval för systemet. Parametervalen testades på drönaren och AMIGO metoden gav de bästa resultaten. De olika lasterna som testades var 4.7, 6.1 och 10.8 gram. AMIGO metoden kunde användas för att reglera drönaren upp till 6.1 gram därefter blev drönarens beteende allt för olinjärt. Sammanfattningsvis går det att använda en PID som ställs in med AMIGO metoden från stegsvaret för att reglera en drönare med mindre laster upp till ungefär sex gram. / This project tested how a drone can be controlled when loads are applied to it. First four different control methods were analyzed, two model based and two non-model based. The two model based were linear quadratic regulator and model predictive control. The two non-model based were cascade control and PID regulator. The PID regulator were chosen and three different methods to tune the PID was tested. Ziegler-Nichols, lambda and AMIGO method, all used the step response from the system to determine the parameters. These different methods gave different setup of parameters and the best result came from the AMIGO method. The different loads that were applied to the system was 4.7, 6.1 and 10.8 gram. The AMIGO method were able to tune the PID up to 6.1 grams, then the system lost to much of its linear behavior. To summarize the work a PID tuned by the AMIGO method using the step response were able to control a drone with a load up to about six grams.

Ingeniero Civil Eléctrico / Una de las principales variables a controlar en un sistema eléctrico es la frecuencia. Para asegurar su estabilidad en las 2 etapas de control (control primario (CPF) y secundario de frecuencia (CSF)) se hace imprescindible un correcto ajuste de las ganancias de los reguladores involucrados. A través de esta memoria se busca proponer una metodología para el ajuste óptimo de reguladores PI encargados del CPF, los cuales pueden ser de frecuencia o potencia-frecuencia. Existe una infinidad de técnicas para definir los parámetros de los reguladores PI, no obstante no todas se ajustan al contexto de regulación de frecuencia utilizando centrales hidráulicas. En esta memoria se estudiaron 2 metodologías: ajuste según Bode y según Ziegler-Nichols. A través de un modelo lineal se aplicaron dichas metodologías al caso particular de la central Colbún. Luego, llevando los mismos ajustes a un modelo no lineal del sistema, se evaluó el desempeño de los reguladores para distintos escenarios y configuraciones: operación en isla y red; distintos niveles de potencia; diferentes niveles de cota de embalse. Para los casos en que la central opera con una cota alta y ésta se encuentra en la sección ancha de la chimenea de equilibrio que posee el sistema, los resultados muestran una respuesta que cumple con las exigencias presentadas en la Norma Técnica. Sin embargo, para cotas inferiores, cuando la cota pasa a la sección angosta de la chimenea, se observan respuestas no acorde a lo exigido. Para ello fue necesario proponer ajustes adicionales. De los resultados se observó que con el reajuste propuesto se cumplen con las exigencias de la Norma Técnica. Luego de establecer una comparación entre las respuestas del modelo no lineal y lineal, se obtuvo que para las condiciones de cota alta es posible utilizar el modelo lineal como una buena aproximación del no lineal. Luego, el análisis realizado para el CSF se realizó utilizando el modelo lineal. Se empleó un modelo de 2 centrales, con 2 generadores en cada una, donde una central se encarga exclusivamente del CPF mientras que la otra se encarga del CSF. Se ajustaron los principales parámetros del regulador encargado del CSF: la constante de tiempo del bloque integral y la tasa de toma de carga de las unidades. A través de las simulaciones se observó que el ajuste cumple con las exigencias fijadas por la Norma Técnica. El Artículo 3-17 de la Norma Técnica propone 2 alternativas para el control secundario de frecuencia: un control centralizado en el CDEC y uno localizado en una central (en este caso Colbún). Utilizando el sistema mencionado en el párrafo anterior, se estudiaron y compararon ambas alternativas. Se observó que la opción de un control localizado en una central es una solución simple, eficiente y viable, mientras que la alternativa de un control centralizado conlleva dificultades como lo son la presencia de oscilaciones sostenidas en el tiempo (ciclos límite), las cuales se deben a la presencia de retardos en el envío y recepción de las señales y a la difcultad de coordinación entre las tomas de carga de las unidades y la fijada por el CDEC.

The increase of intelligent systems can be seen in every industry. Integrated sensors and processors are used with internal control systems to create better performance for mobile hydraulic applications. The report describes how an evaluation was made to see if the productivity of a drill rig could be increased. This was done by implementing a programmable hydraulic valve to control the hydraulic drilling functions. The productivity would be increased by reducing the downtime due to jamming in the drill hole. Jamming occur when the system does not compensate for changes in rock conditions. By conducting a series of tests in a controlled environment with simulated loads, the response time of the CMA system and original system could be determined and compared. The CMA system had a response time that was 60-64% faster than the original system. Two different implementations of a controller was tested. Ziegler-Nichols method was used to get the initial value of the PI parameters. The controller that was implemented onboard the valve’s CPU was considered more successfull to reduce jamming. A drill test was conducted to ensure that the programmable valve could handle a drilling procedure with the controller that was implemented onboard the valve’s CPU. The valve handled the drilling procedure well.

Hydropower is an important part of renewable power production in Sweden. The voltage stability of the already existing hydropower needs to be improved. One way to do this is by improving the control system that damp terminal voltage oscillations. If the oscillations in the power system are not damped it could lead to lower power outputs or in the worst case a blackout. This thesis focuses on the automatic voltage regulator (AVR) system with a proportional, integral, derivative (PID) controller. The PID controller’s parameters are optimized to dampen the terminal voltage instability in a generator. The aim is to develop a machine learning model that predicts the optimal gain parameters for a PID controller. The model is using the tuned gains from the Ziegler-Nichols (Z-N) method and the amplifier gain as inputs and gives the optimal gains as output. A linearized model of an AVR system, based on transfer functions was developed in a MATLAB script. This model was used to simulate the behaviours of an AVR system when a change in load occurs. The Z-N method and the genetic algorithm (GA) with different settings and fitness functions were used to tune a PID controller. The best performing method is GA with the fitness function developed by Zwe-Lee Gaing (ZL).  The best performing settings are: roulette selection, adapt feasible mutation, and arithmetic crossover. The GA (ZL) was used in the development of a machine learning model. Two different models were developed and tested: the support vector regression (SVR) and the gaussian process regression (GPR). The data that was used to train the models were generated by changing the transfer functions’ time constants 4096 times. At each step, the Z-N, and the GA (ZL) were run. The GPR model is shown to be the superior model with a lower root mean square error (RMSE) and a higher ratio of variation (R^2). The RMSE for GPR is 0.1091, 0.0815, 0.0717 and the R^2 is 87 %, 59 %, and 86%. The result shows that the developed model has capabilities to optimize the PID controller gains of any AVR-system without knowing the characteristics of the components.

The master’s thesis deals with method of adaptive control of electrical drives. It aims at control of DC motor with using self tunning controller (STC) and gain-schedulink in simulative enviroment of MATLAB. The first part of the thesis deals with of basic methods adaptive control of electrical drives and with of basic identification methods, computation of controller parameters and control laws of controllers. The second part of the thesis is aimed at applying adaptive controllers to mathematical model of controlled system. Include monitoring parameters of identification The thesis contains originate programs include source files.