The main goal of the paper is to test the Embedded Model Control (EMC) design and implementation on a typical underactuated apparatus, like the Furuta pendulum, by comparing experimental results with ...a Linear Quadratic Regulator (LQR). EMC can be considered as a disturbance rejection control strategy, since the state predictor is extended to explicitly include disturbance dynamics, in charge of predicting the uncertainty to be rejected by control law. Essential in EMC design is the separation between controllable and not controllable dynamics, a task which allows us to find the controllable channel of underactuated systems from the low-dimensional command to the whole system degrees of freedom (DF). Pursuing this objective, a rather generic method is shown, which is applicable to other underactuated systems. The result is a very simple controllable dynamics from the single pendulum command to pendulum DF arranged in a single series of controllable integrators. The neglected feedback channels, including the unstable gravity feedback, are treated as unknown thus posing a challenge to disturbance prediction and closed loop stability. Typical in EMC, closed loop eigenvalues are chosen to guarantee stability, a pre-requisite to performance. Experimental results point out effectiveness and advantage, with respect to LQR, of design and implementation under adverse conditions, due to a disturbance pulse, in which command saturates.
•Model-based framework Embedded Model Control is developed for underactuated systems.•Controllable system is transformed into a series of integrators from command-output.•Two decoupled dynamic feedback low order noise/disturbance observers are designed.•Stability is analysed by measurement law and the control law, designed separately.•Experimental tests are done on the Furuta Pendulum showing requirements are achieved.
Hierarchical control architectures are a common approach when hydraulic systems are under study; provided their multi-domain nature, the control scheme is commonly split into different hierarchical ...levels each one associated with a particular physical domain. This paper presents the application of a model-based control structure called Embedded Model Control (EMC) when a hierarchical scheme is implemented on an electro-hydraulic proportional valve. The overall control consists of two hierarchical loops: the inner loop is the solenoid current regulator with a closed loop bandwidth close to 1kHz. The outer loop is a position tracking control, in charge of the accurate positioning of the spool with respect to valve openings. The paper addresses the outer loop, i.e., the tracking of mechanical spool position by using the EMC. Analysis and synthesis are presented as well as experimental results obtained from a test rig provided by an industrial manufacturer.
•The outer loop of a hierarchical controller for proportional valves is designed by using the Embedded Model Control.•Design is supported by a discrete-time embedded model obtained from experimental data.•Parametric uncertainty and neglected dynamics are addressed by disturbance estimation and cancelation through the control law.•Experimental results show that the demanding requirements are achieved by the implementation of the EMC framework.
•Lithium-ion batteries are well adapted for use in solar home systems.•Market success requires that application specific battery-packs are dveloped.•There is a satisfactory commercial offer on ...suitable cells and power electronics.•The economic barrier for implementation is low at the energy cost level.•High initial costs hamper affordability on the short run requiring financing solutions.
Solar home systems provide effective power supply solutions for off-grid households in developing regions. The standard battery in such systems is currently lead-acid. Nevertheless, recent and foreseeable developments in lithium-ion batteries favor their use in such application, resulting in significant advantages, including light and compact layout, outstanding performance, reliable operation and long cycle life. This paper explores this implementation potential by detailing the engineering aspects of lithium-ion battery-packs for solar home systems, and elaborating on the key cost factors, present and future. It is concluded that the technology is mature for the solar home system market. Furthermore, despite the relatively high initial cost, the lithium-ion battery is competitive at the level of energy storage cost. Ongoing cost reductions will favor the accelerated use of lithium-ion batteries in this application. More favorable conditions to reduce implementation barriers would be created via tailored funding programs and financing schemes.
Este trabajo presenta la implementación de un diagnosticador de fallos en línea, para la detección de fallos operacionales presentes en la planta piloto de procesamiento de aguas, en el marco del ...proyecto REAGRITECH de la cátedra Unesco de sostenibilidad, modelada como un sistema de eventos discretos (SED), haciendo uso de redes de Petri interpretadas (IPN). Se realiza un análisis de funcionamiento del sistema real, del cual se identifican algunas escenas de funcionamiento, que permiten la construcción de un controlador encargado de representar, de forma simulada, el comportamiento real de la planta. A partir de este, se obtiene una matriz de información de entradas-salidas (E/S), donde las entradas corresponden a las señales de mando de control, y las salidas son las señales de sensores. Estos datos se ingresan como parámetros a un algoritmo de identificación, que entrega como resultado el modelo de la IPN identificado a partir de los datos, es decir, información de una IPN: matriz de incidencia A, función de entrada (Fe) con las etiquetas asociadas a las transiciones, la función de salida (Fs) y una matriz de salida φ que relaciona los sensores con cada plaza del sistema. Con base en el modelo identificado se realiza un análisis de detectabilidad para saber si el sistema es detectable o no por eventos, y se construye un diagnosticador a partir de fallos predefinidos. Se concluye que el diagnosticador implementado es capaz de detectar fallos presentes en la planta piloto de procesamiento de agua, en el marco del proyecto REAGRITECH, haciendo un análisis del marcado en los lugares de diagnóstico y en los lugares Post de riesgos del sistema.
Este trabajo presenta el análisis e implementación de dos leyes de control aplicadas en un caso de estudio. La primera y el enfoque principal de este trabajo es el control a modelo embebido cuyas ...características fundamentales son la cancelación activa de disturbios y el manejo de incertidumbres. Aquí se prueban diferentes configuraciones para los parámetros del control logrando que los límites en el desempeño queden expuestos debido a las limitaciones del modelo. Por otro lado se encuentra la ley de control PID clásica basada en acciones sobre el error de trayectoria como un paradigma de control que no requiere de un modelo para su ejecución. La implementación y pruebas se hacen en una planta didáctica comercial, donde se verifican las propiedades de desempeño y rechazo a perturbaciones mostrando que aun en este simple proceso el desempeño puede verse degradado debido a la ausencia de un modelo de la planta embebido en la ley de control
This paper deals with multilayer and fine thermal control of an optical reference cavity for space applications. The cavity, made of ultralow-expansion glass, must be kept close to the zero-expansion ...temperature (ZET) of the glass (near room temperature). The target can only be met by active control, while leaving the cavity free of sensors and actuators. This is achieved by applying two concepts: thermal bath and reference thermal sink, the latter allowing the ZET to be reached by heaters in a wide range of the environment. Guidelines for cavity design and thermal control implementation are detailed together with preliminary experimental results.
Hierarchical control architecture is a common to hydraulic systems. This paper outlines the application of a model-based control referred to as Embedded Model Control for implementing the ...hierarchical position control of an electro-hydraulic proportional valve. The hierarchy consists of two loops: the inner loop is the solenoid current regulator with a closed loop bandwidth close to 1 kHz. The outer loop is a position tracking control, in charge of the spool accurate positioning with respect to the valve openings. The paper focuses on the outer position loop. Analysis and synthesis are presented as well as experimental results obtained from a test rig provided by the valve manufacturer.
En este trabajo se presenta el desarrollo de un prototipo para el monitoreo de humedad y el control de la temperatura del secado del café en la Institución Educativa Agropecuaria La Capilla (Cajibío ...- Cauca). El prototipo fue desarrollado usando instrumentación electrónica y diseño asistido por computador. El sistema de control diseñado permite realizar de manera automática el proceso de secado. Se diseñó un equipo mecánico tipo silo, con una capacidad total de 5 kg de carga permitiendo una disminución en el tiempo de secado en comparación con el secado manual.
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