ESTIMACIÓN DE LOS COEFICIENTES DE INERCIA Y DE FRICCIÓN DE UN MOTOR DE CD (ESTIMATION OF INERTIA AND FRICTION COEFFICIENTS OF A DC MOTOR)

ResumenEn este trabajo se presentan algunos modelos de fricción, y se destaca la importancia de los parámetros de fricción viscosa y de Coulomb, los cuales son necesarios para definir los distintos modelos que describen el comportamiento de la fricción en sistema mecánicos. Se describen los métodos de torque constante y entrada tipo rampa para estimar los coeficientes de fricción viscosa y de Coulomb, estos métodos se aplican en un motor de CD para obtener sus parámetros. A fin de comprobar que los parámetros estimados son los adecuados, se diseña y se aplica un control de velocidad, utilizando un controlador proporcional con compensación. La estimación de los parámetros y el control de velocidad del motor se realiza de forma experimental utilizando una plataforma de Arduino UNO en conjunto con la herramienta de Simulink de MatLab. Los resultados muestran que los coeficientes de fricción estimados son adecuados.Palabras Claves: control, estimación, fricción, motor de cd. AbstractIn this paper, some friction models are presented, highlighting the importance of viscous and Coulomb friction parameters, which are necessary to define the different models that describe the friction behavior in mechanical systems. The constant torque and ramp-type input methods for estimating viscous and Coulomb friction coefficients are described. These methods are applied in a DC motor, and their parameters are obtained. To verify that the estimated parameters are adequate, a speed control is designed and applied, using a proportional controller with compensation. Parameter estimation and motor speed control is performed experimentally using an Arduino UNO platform together with Simulink tool of MatLab. The results show that the estimated friction parameters are adequate.Keywords: control, friction, measurement, dc motor

Robust Predictive Extended State Observer for a Class of Nonlinear Systems with Time-Varying Input Delay

[EN] This paper deals with asymptotic stabilisation of a class of nonlinear input-delayed systems via dynamic output feedback in the presence of disturbances. The proposed strategy has the structure of an observer-based control law, in which the observer estimates and predicts both the plant state and the external disturbance. A nominal delay value is assumed to be known and stability conditions in terms of linear matrix inequalities are derived for fast-varying delay uncertainties. Asymptotic stability is achieved if the disturbance or the time delay is constant. The controller design problem is also addressed and a numerical example with an unstable system is provided to illustrate the usefulness of the proposed strategy.This work was partially supported by: Ministerio de Economía y Competitividad, Spain (TIN2017-86520-C3-1-R); Universitat Politècnica de València (FPI-UPV 2014 PhD Grant); and Israel Science Foundation (Grant No. 1128/14).Sanz Diaz, R.; García Gil, PJ.; Fridman, E.; Albertos Pérez, P. (2020). Robust Predictive Extended State Observer for a Class of Nonlinear Systems with Time-Varying Input Delay. International Journal of Control. 93(2):217-225. https://doi.org/10.1080/00207179.2018.1562204S217225932Ahmed-Ali, T., Cherrier, E., & Lamnabhi-Lagarrigue, F. (2012). Cascade High Gain Predictors for a Class of Nonlinear Systems. IEEE Transactions on Automatic Control, 57(1), 221-226. doi:10.1109/tac.2011.2161795Artstein, Z. (1982). Linear systems with delayed controls: A reduction. 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