On the synthesis of piecewise affine control laws

Abstract-Piecewise affine (PWA) control laws offer an attractive solution to real-time control of linear, nonlinear and hybrid systems. In this paper we provide a compact exposition of the existing state-of-the-art methods for the synthesis of PWA control laws using optimization-based methods

Energy Management and Control of Electrical Drives in Hybrid Electrical Vehicles

Hybrid vehicles have attracted tremendous attention during the last years. Increasing environmental concern and a steady increase in fuel prices are key factors for the growing interest. Hybrid vehicles, which benefits from having at least two different energy converters and two different energy storage systems, have proven to have significant potential to improve fuel economy without reducing the performance of the vehicle. However, the extra degree of freedom inherited by the use of two energy sources on-board the vehicle, gives rise to a more complicated energy management control. The first part of the thesis treats the subject of energy management in hybrid electrical vehicles. The gain in fuel consumption and the minimization of emissions are highly dependent on the performance of the control strategy. A rather simple heuristic control strategy presented in the literature is optimized. Heuristic control strategies are often referred to as hard to tune, and none optimal. However, the result presented in the thesis shows that the strategy is easily tuned, robust and has no significant cycle-beating trait. Dynamic programming is used to obtain a global optimal solution to the control problem. The result of this global optimization is then used as a basis for evaluating the real-time heuristic control strategy and serves as a lower bound for the fuel consumption for a given cycle. A comparison of fuel consumption for the two control strategies shows that, though being quite simple, the heuristic control strategy gives a relatively near-optimal result. The second part of the thesis is devoted to the development of an electrically driven rear axle for a HEV in collaboration with SAAB Automobile. A rear drive unit, consisting of an electrical machine, planetary gear and a differential, was provided by SAAB. Focus is on control and thermal modeling of the electrical machine. A simple and effective field weakening controller, giving fast field weakening performance is proposed. The fast field weakening performance is important in a HEV since the battery voltage undergoes rapid variations, during accelerations. In addition to this, the FWC minimizes the torque-per-current ratio by, for a given torque, using the current combination yielding the minimal stator current. In addition to this, a thermal model based on several thermal measurements is proposed and validated against data. The thermal model forms the basis for the derivation of an over temperature controller, preventing the machine from over heating

A comprehensive study of key Electric Vehicle (EV) components, technologies, challenges, impacts, and future direction of development

Abstract: Electric vehicles (EV), including Battery Electric Vehicle (BEV), Hybrid Electric Vehicle (HEV), Plug-in Hybrid Electric Vehicle (PHEV), Fuel Cell Electric Vehicle (FCEV), are becoming more commonplace in the transportation sector in recent times. As the present trend suggests, this mode of transport is likely to replace internal combustion engine (ICE) vehicles in the near future. Each of the main EV components has a number of technologies that are currently in use or can become prominent in the future. EVs can cause significant impacts on the environment, power system, and other related sectors. The present power system could face huge instabilities with enough EV penetration, but with proper management and coordination, EVs can be turned into a major contributor to the successful implementation of the smart grid concept. There are possibilities of immense environmental benefits as well, as the EVs can extensively reduce the greenhouse gas emissions produced by the transportation sector. However, there are some major obstacles for EVs to overcome before totally replacing ICE vehicles. This paper is focused on reviewing all the useful data available on EV configurations, battery energy sources, electrical machines, charging techniques, optimization techniques, impacts, trends, and possible directions of future developments. Its objective is to provide an overall picture of the current EV technology and ways of future development to assist in future researches in this sector

Gear shift strategies for automotive transmissions

The development history of automotive engineering has shown the essential role of transmissions in road vehicles primarily powered by internal combustion engines. The engine with its physical constraints on the torque and speed requires a transmission to have its power converted to the drive power demand at the vehicle wheels. Under dynamic driving conditions, the transmission is required to shift in order to match the engine power with the changing drive power. Furthermore, a gear shift decision is expected to be consistent such that vehicle can remain in the next gear for a period of time without deteriorating the acceleration capability. Therefore, an optimal conversion of the engine power plays a key role in improving the fuel economy and driveability. Moreover, the consequences of the assumptions related to the discrete state variable-dependent losses, e.g. gear shifting, clutch slippage and engine starting, and their e¿ect on the gear shift control strategy are necessary to be analyzed to yield insights into the fuel usage. The ¿rst part of the thesis deals with the design of gear shift strategies for electronically controlled discrete ratio transmissions used in both conventional vehicles and Hybrid Electric Vehicles (HEVs). For conventional vehicles, together with the fuel economy, the driveability is systematically addressed in a Dynamic Programming (DP) based optimal gear shift strategy by three methods: i) the weighted inverse of the power re¬serve, ii) the constant power reserve, and iii) the variable power reserve. In addition, a Stochastic Dynamic Programming (SDP) algorithm is utilized to optimize the gear shift strategy, subject to a stochastic distribution of the power request, in order to minimize the expected fuel consumption over an in¿nite horizon. Hence, the SDP-based gear shift strategy intrinsically respects the driveability and is realtime implementable. By per¬forming a comparative analysis of all proposed gear shift methods, it is shown that the variable power reserve method achieves the highest fuel economy without deteriorating the driveability. Moreover, for HEVs, a novel fuel-optimal control algorithm, consist-ing of the continuous power split and discrete gear shift, engine on-o¿ problems, based on a combination of DP and Pontryagin’s Minimum Principle (PMP) is developed for the corresponding hybrid dynamical system. This so-called DP-PMP gear shift control approach benchmarks the development of an online implementable control strategy in terms of the optimal tradeo¿ between calculation accuracy and computational e¿ciency. Driven by an ultimate goal of realizing an online gear shift strategy, a gear shift map design methodology for discrete ratio transmissions is developed, which is applied for both conventional vehicles and HEVs. The design methodology uses an optimal gear shift algorithm as a basis to derive the optimal gear shift patterns. Accordingly, statis¬tical theory is applied to analyze the optimal gear shift pattern in order to extract the time-invariant shift rules. This alternative two-step design procedure makes the gear shift map: i) respect the fuel economy and driveability, ii) be consistent and robust with respect to shift busyness, and iii) be realtime implementation. The design process is ¿exible and time e¿cient such that an applicability to various powertrain systems con¿gured with discrete ratio transmissions is possible. Furthermore, the study in this thesis addresses the trend of utilizing the route information in the powertrain control system by proposing an integrated predictive gear shift strategy concept, consisting of a velocity algorithm and a predictive algorithm. The velocity algorithm improves the fuel economy in simulation considerably by proposing a fuel-optimal velocity trajectory over a certain driving horizon for the vehicle to follow. The predictive algorithm suc¬cessfully utilizes a prede¿ned velocity pro¿le over a certain horizon in order to realize a fuel economy improvement very close to that of the globally optimal algorithm (DP). In the second part of the thesis, the energetic losses, involved with the gear shift and engine start events in an automated manual transmission-based HEV, are modeled. The e¿ect of these losses on the control strategies and fuel consumption for (non-)powershift transmission technologies is investigated. Regarding the gear shift loss, the study ¿rstly ever discloses a perception of a fuel-e¿cient advantage of the powershift transmissions over the non-powershift ones applied for commercial vehicles. It is also shown that the engine start loss can not be ignored in seeking for a fair evaluation of the fuel economy. Moreover, the sensitivity study of the fuel consumption with respect to the prediction horizon reveals that a predictive energy management strategy can realize the highest achievable fuel economy with a horizon of a few seconds ahead. The last part of the thesis focuses on investigating the sensitivity of an optimal gear shift strategy to the relevant control design objectives, i.e. fuel economy, driveability and comfort. A singu¬lar value decomposition based method is introduced to analyze the possible correlations and interdependencies among the design objectives. This allows that some of the pos¬sible dependent design objective(s) can be removed from the objective function of the corresponding optimal control problem, hence thereby reducing the design complexity

12th EASN International Conference on "Innovation in Aviation & Space for opening New Horizons"

Epoxy resins show a combination of thermal stability, good mechanical performance, and durability, which make these materials suitable for many applications in the Aerospace industry. Different types of curing agents can be utilized for curing epoxy systems. The use of aliphatic amines as curing agent is preferable over the toxic aromatic ones, though their incorporation increases the flammability of the resin. Recently, we have developed different hybrid strategies, where the sol-gel technique has been exploited in combination with two DOPO-based flame retardants and other synergists or the use of humic acid and ammonium polyphosphate to achieve non-dripping V-0 classification in UL 94 vertical flame spread tests, with low phosphorous loadings (e.g., 1-2 wt%). These strategies improved the flame retardancy of the epoxy matrix, without any detrimental impact on the mechanical and thermal properties of the composites. Finally, the formation of a hybrid silica-epoxy network accounted for the establishment of tailored interphases, due to a better dispersion of more polar additives in the hydrophobic resin

Validation of the correct definition of the model of a hybrid system represented in MLD

El principal objetivo del proyecto fue implementar un programa para validar la correcta definición de un sistema dinámico híbrido, representado con un modelo MLD (Mixed Logical and Dynamic System), por lo que el principal aporte del mismo consiste en implementar un algoritmo de validación del modelo MLD, que le permite al diseñador visualizar gráficamente el campo vectorial del sistema. El trabajo incluye una definición de las características de un sistema bien definido, y de lo que se entiende como un sistema mal definido, con lo cual se establecen las especificaciones del algoritmo para dar solución al objetivo especifico de determinar las características de funcionamiento del algoritmo de validación. El algoritmo implementado se basa en la teoría propuesta por Bemporad y Morari; esto constituye la solución del objetivo de implementar y evaluar el algoritmo MILP (Programación Lineal Entera Mixta) con un problema de ejemplo MLD. Debido al alto costo computacional que el algoritmo propuesto presenta, se desarrolla y propone una versión utilizando computación distribuida, con lo cual la solución propuesta resulta de mayor utilidad, dando de esta forma solución al objetivo especifico de proponer un algoritmo mejorado que reduzca el tiempo de computación en el problema MLD. Ambos algoritmos se aplican a tres casos de estudio donde se evalúan los ajustes de parámetros del algoritmo y su respectivo tiempo de ejecución, dando solución al objetivo específico de evaluar el comportamiento del algoritmo propuesto en un problema de estudio. Finalmente con esta aproximación se logra una mejora significativa en los tiempos de ejecución del algoritmo a través de la programación distribuida, se cambia la plataforma de procesamiento y se trabaja con esta filosofía, obteniendo los mismos resultados con una significativa disminución del tiempo de ejecución de dicho algoritmo, en cada uno de los casos.LISTA DE FIGURAS............................................................................................................8 LISTA DE TABLAS............................................................................................................10 LISTA DE ALGORITMOS.................................................................................................11 LISTA DE ANEXOS...........................................................................................................12 1. INTRODUCCION......................................................................................................13 2. SISTEMAS LOGICOS Y DINAMICOS MIXTOS - MLD (MIXED LOGICAL AND DYNAMICAL)...........................................................................................................16 2.1 GENERALIDADES DE SISTEMAS DINAMICOS..........................................16 2.2 EL MODELO MLD ...........................................................................................20 2.3 Equivalencia entre representaciones de Sistemas Híbridos.................................23 2.4 HERRAMIENTAS DE ANALISIS PARA SISTEMAS MLD...........................24 2.4.1 Hysdel (Hybrid System Description Language)..................................................25 2.4.2 Matlab (Matrix laboratory)..................................................................................26 3. CASOS DE ESTUDIO DE SISTEMAS MLD..........................................................29 3.1 DEFINICION FORMAL DE SISTEMAS MLD CORRECTAMENTE DEFINIDOS..................................................................................................................29 3.2 CASOS DE ESTUDIO........................................................................................30 3.2.1 Caso 1 Modelo de un Sistema Bien Definido......................................................31 3.2.2 Caso 2 Modelo de un sistema sin condición de existencia (ausencia de solución) 34 3.2.3 Caso 3 Modelo de un sistema sin condición de unicidad (soluciones múltiples)37 4. ALGORITMO DE VALIDACIÓN............................................................................40 4.1 EL ALGORITMO DE VALIDACIÓN......................................................................40 7 4.1.1 Existencia de soluciones......................................................................................40 4.1.2 Unicidad de soluciones........................................................................................42 4.2 METODO BRANCH & BOUND..............................................................................44 4.3 RESULTADOS Y ANÁLISIS DE RESULTADOS..................................................50 4.4 Complejidad Computacional......................................................................................64 5. ALGORITMO DE VALIDACIÓN CON COMPUTACIÓN DISTRIBUIDA........65 5.1 SOLUCION CON ALGORITMO DISTRIBUIDO IMPLEMENTADO EN JAVA 66 5.2 ALGORITMO FINAL DE VALIDACIÓN BASADO EN COMPUTACIÓN DISTRIBUIDA.....................................................................................................................68 5.3 RESULTADOS Y ANÁLISIS DE RESULTADOS..................................................69 5.3.1 CASO 1. Modelo de un sistema bien definido....................................................69 5.3.2 CASO 2. Modelo de un sistema sin condición de existencia (Ausencia de solución) 70 5.3.3 CASO 3. Modelo de un sistema sin condición de Unicidad (Soluciones Múltiples)72 5.4 COMPLEJIDAD COMPUTACIONAL DEL ALGORITMO DISTRIBUIDO........74 6. CONCLUSIONES Y TRABAJOS FUTUROS........................................................75 6.1 CONCLUSIONES......................................................................................................75 6.2 TRABAJOS FUTUROS.............................................................................................76 BIBLIOGRAFÍA........................................................................................................78 ANEXOS..............................................................................................................................84MaestríaThe main objective of the project was to implement a program to validate the correct definition of a hybrid dynamic system, represented with an MLD (Mixed Logical and Dynamic System) model, so its main contribution consists in implementing a model validation algorithm MLD, which allows the designer to graphically visualize the vector field of the system. The work includes a definition of the characteristics of a well-defined system, and of what is understood as a poorly defined system, which establishes the specifications of the algorithm to solve the specific objective of determining the operating characteristics of the algorithm of validation. The implemented algorithm is based on the theory proposed by Bemporad and Morari; this constitutes the solution of the objective of implementing and evaluating the MILP (Mixed Integer Linear Programming) algorithm with an example MLD problem. Due to the high computational cost that the proposed algorithm presents, a version is developed and proposed using distributed computing, with which the proposed solution is more useful, thus providing a solution to the specific objective of proposing an improved algorithm that reduces the time of computation in the MLD problem. Both algorithms are applied to three study cases where the parameter settings of the algorithm and their respective execution time are evaluated, providing a solution to the specific objective of evaluating the behavior of the algorithm proposed in a study problem. Finally, with this approach, a significant improvement in algorithm execution times is achieved through distributed programming, the processing platform is changed and this philosophy is used, obtaining the same results with a significant decrease in the execution time of said algorithm. algorithm, in each of the cases

Validación de la correcta definición del modelo de un sistema híbrido representando en MLD

El grupo de investigación GAICO de la UTB, cuya principal línea de investigación ha sido en modelamiento y control de sistemas industriales, ha abordado el tema a través de lo que se conoce en la literatura técnica como sistemas dinámicos híbridos, y en particular a través de un modelo denominado Sistemas Lógicos y Dinámicos mezclados (mixed logical and dynamical – MLD systems); los sistemas lógicos y dinámicos mezclados pueden ser representados como un sistema aparentemente lineal con desigualdades con forma lineal, pero una parte de sus variables solo pueden tener valores binarios [8]. Ya el grupo ha utilizado esta representación para resolver problemas de simulación y problemas de control predictivo, sin embargo, los algoritmos utilizados requieren enumerar, en cierto modo, las posibles soluciones factibles del problema, y por ello el algoritmo tiene complejidad computacional No Determinística Polinomial NP, adicionalmente es difícil encontrar errores de modelamiento en la estructura matemática, debido al potencialmente alto número de restricciones que se pueden requerir para representar el sistema [7]. Debido al potencialmente alto número de restricciones que pueden estar incluidas en el modelo MLD, la representación puede ser de difícil evaluación por parte del usuario final. En nuestro conocimiento no se ha implementado ningún algoritmo que permita verificar la validez del modelo ML

INTER-ENG 2020

These proceedings contain research papers that were accepted for presentation at the 14th International Conference Inter-Eng 2020 ,Interdisciplinarity in Engineering, which was held on 8–9 October 2020, in Târgu Mureș, Romania. It is a leading international professional and scientific forum for engineers and scientists to present research works, contributions, and recent developments, as well as current practices in engineering, which is falling into a tradition of important scientific events occurring at Faculty of Engineering and Information Technology in the George Emil Palade University of Medicine, Pharmacy Science, and Technology of Târgu Mures, Romania. The Inter-Eng conference started from the observation that in the 21st century, the era of high technology, without new approaches in research, we cannot speak of a harmonious society. The theme of the conference, proposing a new approach related to Industry 4.0, was the development of a new generation of smart factories based on the manufacturing and assembly process digitalization, related to advanced manufacturing technology, lean manufacturing, sustainable manufacturing, additive manufacturing, and manufacturing tools and equipment. The conference slogan was “Europe’s future is digital: a broad vision of the Industry 4.0 concept beyond direct manufacturing in the company”

Hybrid control of an automotive robotized gearbox for reduction of consumptions and emissions

This paper describes the application of hybrid modeling and receding horizon optimal control techniques for supervising an automotive robotized gearbox, with the goal of reducing consumptions and emissions, a problem that is currently under investigation at Fiat Research Center (CRF). We show that the dynamic behavior of the vehicle can be easily approximated and captured by the hybrid model, and through simulations on standard speed patterns that a good closed loop performance can be achieved. The synthesized control law can be implemented on automotive hardware as a piecewise affine function of the measured and estimated quantities