Event-based control of basic wastewater treatment plant control loops

[Abstract] This paper addresses the problem of basic control loops in wastewater treatment plants. By basic control loops we are referring to the traditional dissolved oxygen and nitrates. They are the basic controls more sophisticated control solutions can be based upon. Therefore it is important that these loops perform in an efficient way. The problem is addressed here within the framework provided by the Benchmark Simulation Model Number 1 (BSM1) and by the use of an event-based solution. It will be verified that the solution can slightly improve the performance of the already exiting controllers both at loop level as well as at plant operation level.[Resumen] Este documento aborda el problema de los bucles de control básicos en las plantas de tratamiento de aguas residuales. Por bucles de control básicos nos referimos a los tradicionales disueltos de oxígeno y nitratos. Son los controles básicos en los que se pueden basar las soluciones de control más sofisticadas. Por lo tanto, es importante que estos bucles funcionen de manera eficiente. El problema se aborda aquí dentro del marco provisto por el Número de modelo de simulación de referencia (BSM1) y por el uso de una solución basada en eventos. Se verificará que la solución puede mejorar ligeramente el rendimiento de los controladores que ya existen, tanto a nivel de bucle como a nivel de operación de la planta

PID Tuning: Analytical approach based on the weighted Sensitivity problem

[EN] The PID controller is the most common option in the realm of control applications and is dominant in the process control industry. Among the related analytical methods, Internal Model Control (IMC) has gained remarkable industrial acceptance due to its robust nature and good set-point responses. However, the traditional application of IMC results in poor load disturbance rejection for lag-dominant and integrating plants. This work presents an IMC-like design method which avoids this common pitfall and is devised to work well for plants of modest complexity, for which analytical PID tuning is plausible. For simplicity, the design only focuses on the closed-loop sensitivity function. The approach provides model-based tuning of single-loop PID controllers in terms of the robustness/performance and servo/regulator trade-offs. Although the robustness/performance compromise is commonly considered, it is not so common to also take into account, for example, the conflict between input and output disturbances, referred also as the servo/regulator trade-off. As interested in providing a unified tuning approach, it is shown how the proposed methodology allows to deal with different process dynamics in a unified way.[ES] El controlador PID es la opción más común en el ámbito de las aplicaciones de control, siendo la opción predominante en el control de procesos industriales. Entre los métodos analíticos más usuales utilizados para su diseño, el Control por Modelo Interno (IMC) ha ganado una notable aceptación industrial debido a su naturaleza robusta y buenas respuestas ante cambios de consigna. Sin embargo, la aplicación tradicional del IMC da como resultado un bajo rendimiento para el rechazo de perturbaciones en carga para plantas integradoras y/o con largas constantes de tiempo. Este trabajo presenta un método de diseño, basado en IMC, que evita esta deficiencia y está diseñado para funcionar bien en plantas de complejidad moderada para las cuales, por otro lado, el ajuste analítico de un controlador PID es plausible. Por simplicidad, el diseño solo se centra en la función de sensibilidad en lazo cerrado. El enfoque proporciona un ajuste basado en modelo en términos de los compromisos robustez/rendimiento y de servo/regulación. Aunque comúnmente se considera el compromiso robustez/rendimiento, no es tan común tener en cuenta también, por ejemplo, el conflicto entre las perturbaciones de entrada y salida, también conocido como el compromiso servo/regulación. Con el objetivo de proporcionar un enfoque de ajuste unificado, se muestra como la metodología propuesta permite tratar diferentes dinámicas de proceso de manera unificada.Los autores desean agradecer al Ministerio de Economía y Competitividad bajo las subvenciones DPI-2016-77271-R y PID2019-105434RB-C33 por la ayuda que han supuesto en la elaboración de los trabajos que han conducido a los desarrollos aquí presentados.Vilanova, R.; Alcántara, S.; Pedret, C. (2021). Sintonía de controladores PID: un enfoque analítico basado en el moldeo de la función de sensibilidad. Revista Iberoamericana de Automática e Informática industrial. 18(4):313-326. https://doi.org/10.4995/riai.2021.15422OJS313326184Alcántara, S., Vilanova, R., Pedret, C., 2013. PID control in terms of robustness/performance and servo/regulator trade-offs: A unifying approach to balanced autotuning. Journal of Process Control 23 (4), 527 - 542. https://doi.org/10.1016/j.jprocont.2013.01.003Alcántara, S., Pedret, C., Vilanova, R., 2010. On the model matching approach to PID design: Analytical perspective for robust Servo/Regulator tradeoff tuning. Journal of Process Control 20 (5), 596 - 608. https://doi.org/10.1016/j.jprocont.2010.02.011Alcántara, S., Pedret, C., Vilanova, R., Skogestad, S., 2011a. Generalized Internal Model Control for balancing input/output disturbance response. Industrial & Engineering Chemistry Research 50 (19), 11170-11180. https://doi.org/10.1021/ie200717zAlcántara, S., Vilanova, R., Pedret, C., 2020. PID Tuning: A Modern Approach via the Weighted Sensitivity Problem (1st ed.). CRC Press. https://doi.org/10.1201/9780429325335-1Alcántara, S., Vilanova, R., Pedret, C., Skogestad, S., 2012. A look into robustness/performance and servo/regulation issues in PI tuning. In: Proc. of the IFAC Conf. on Advances in PID Control PID'12. https://doi.org/10.3182/20120328-3-IT-3014.00031Alcántara, S., Zhang, W., Pedret, C., Vilanova, R., Skogestad, S., 2011b. IMC-like analytical H-inf design with S/SP mixed sensitivity consideration: Utility in PID tuning guidance. Journal of Process Control 21 (6), 976 - 985. https://doi.org/10.1016/j.jprocont.2011.04.007Alfaro, V. M., Vilanova, R., 2013a. Performance and Robustness Considerations for Tuning of Proportional Integral/Proportional Integral Derivative Controllers with Two Input Filters. Industrial & Engineering Chemistry Research 52, 18287-18302. https://doi.org/10.1021/ie4012694Alfaro, V. M., Vilanova, R., 2013b. Robust tuning of 2DoF five-parameters PID controllers for inverse response controlled processes. Journal of Process Control 23, 453-462. https://doi.org/10.1016/j.jprocont.2013.01.005Alfaro, V. M., Vilanova, R., September 2013c. Simple robust tuning of 2DoF PID controllers from a performance/robustness trade-off analysis. Asian Journal of Control 15 (5), 1-14. https://doi.org/10.1002/asjc.653Alfaro, V. M., Vilanova, R., 2016. Model-Reference Robust Tuning of PID Controllers. Springer International Publishing AG, Gewerbestrasse 11, 6330 Cham, Switzerland, ISBN 978-3-319-28213-8.Alfaro, V. M., Vilanova, R., Méndez, R., Lafuente, J., 2010. Performance/Robustness Tradeoff Analysis of PI/PID Servo and Regulatory Control Systems. In: Proc. of the IEEE International Conference on Industrial Technology. https://doi.org/10.1109/ICIT.2010.5472662Arrieta, O., Vilanova, R., 2012. Simple servo/regulation proportional-integralderivative (pid) tuning rules for arbitrary ms-based robustness achievement. Industrial & Engineering Chemistry Research 51 (6), 2666-2674. https://doi.org/10.1021/ie201655cArrieta, O., Vilanova, R., Rojas, J. D., Meneses, M., 2016. Improved pid controller tuning rules for performance degradation/robustness increase trade-off. Electrical Engineering 98 (3), 233-243. https://doi.org/10.1007/s00202-016-0361-xArrieta, O., Visioli, A., Vilanova, R., 2010. PID autotuning for weighted servo/regulation control operation. Journal of Process Control 20 (4), 472 -480. https://doi.org/10.1016/j.jprocont.2010.01.002Astrom, K., Hagglund, T., 2004. Revisiting the Ziegler-Nichols step response method for PID control. J. Process Control 14, 635-650. https://doi.org/10.1016/j.jprocont.2004.01.002Astrom, K., Hagglund, T., 2005. Advanced PID control. ISA - The Instrumentation, Systems, and Automation Society.Chien, I. L., Fruehauf, P. S., 1990. Consider IMC tuning to improve controller performance. Chemical Engineering Progress 86 (10), 33 - 41.Dehghani, A., Lanzon, A., Anderson, B., 2006. H1 design to generalize internalmodel control. Automatica 42 (11), 1959 - 1968.Grimholt, C., Skogestad, S., 2012. Optimal PI Control and Verifcation of the SIMC Tuning Rule. In: Proc. of the IFAC Conf. on Advances in PID Control PID'12. https://doi.org/10.3182/20120328-3-IT-3014.00003Horn, I. G., Arulandu, J. R., Gombas, C. J., VanAntwerp, J. G., Braatz, R. D., 1996. Improved Filter Design in Internal Model Control. Industrial & Engineering Chemistry Research 35 (10), 3437 - 3441. https://doi.org/10.1021/ie9602872Huba, M., 2012. Setpoint Versus Disturbance Responses of the IPDT Plant. In: Proc. of the IFAC Conf. on Advances in PID Control PID'12. https://doi.org/10.3182/20120328-3-IT-3014.00070J.Shi, W.S.Lee, 2004. Set Point Response and Disturbance Rejection Tradeoff for Second-Order Plus Dead Time Processes. In: Asian Control Conference.Kristiansson, B., Lennartson, B., 1998. Optimal PID controllers for unstable and resonant plants. In: Proc. of the IEEE Conference on Decision and Control. pp. 4380-4381.Kurokawa, R., Sato, T., Vilanova, R., Konishi, Y., 2019. Discrete-time firstorder plus dead-time model-reference trade-off pid control design. Applied Sciences 9 (16). https://doi.org/10.3390/app9163220Kurokawa, R., Sato, T., Vilanova, R., Konishi, Y., 2020. Design of optimal pid control with a sensitivity function for resonance phenomenon-involved second-order plus dead-time system. Journal of the Franklin Institute 357 (7), 4187-4211. https://doi.org/10.1016/j.jfranklin.2020.03.015Leva, A., Maggio, M., 2012. Model-Based PI(D) Autotuning. In: PID Control in the Third Millennium. Lessons Learned and New Approaches. Springer. https://doi.org/10.1007/978-1-4471-2425-2_2Mercader, P., Astrom, K. J., Baños, A., Hagglund, T., 2017a. Robust pid design based on qft and convex?concave optimization. IEEE Transactions on Control Systems Technology 25 (2), 441-452. https://doi.org/10.1109/TCST.2016.2562581Mercader, P., Baños, A., 2017. A pi tuning rule for integrating plus dead time processes with parametric uncertainty. ISA Transactions 67, 246-255. https://doi.org/10.1016/j.isatra.2017.01.025Mercader, P., Baños, A., Vilanova, R., 2017b. Robust proportional-integral-derivative design for processes with interval parametric uncertainty. IET Control Theory & Applications 11 (7), 016-1023. https://doi.org/10.1049/iet-cta.2016.1239Mercader, P., Soltesz, K., Baños, A., 2017c. Robust pid design by chance-constrained optimization. Journal of the Franklin Institute 354 (18), 8217-8231. https://doi.org/10.1016/j.jfranklin.2017.10.017Meza, G. R., Ferragud, X. B., Saez, J. S., Dur, J. M. H., 2016. Controller Tuning with Evolutionary Multiobjective Optimization: A Holistic Multiobjective Optimization Design Procedure, 1st Edition. Springer Publishing Company, Incorporated.Middleton, R. H., Graebe, S. F., 1999. Slow stable open-loop poles: to cancel or not to cancel. Automatica 35 (5), 877-886. https://doi.org/10.1016/S0005-1098(98)00220-9Morari, M., Zafiriou, E., 1989. Robust Process Control. Prentice-Hall International.Panagopoulos, H., Astrom, K. J., 2000. PID control design and H1 loop shaping. International Journal of Robust and Nonlinear Control 10 (15), 1249-1261. https://doi.org/10.1002/1099-1239(20001230)10:153.0.CO;2-7Pedret, C., Vilanova, R., Moreno, R., Serra, I., 2002. A refinement procedure for PID controller tuning. Computers & Chemical Engineering 26 (6), 903- 908. https://doi.org/10.1016/S0098-1354(02)00011-XRivera, D. E., Morari, M., Skogestad, S., 1986. Internal model control: PID controller design. Industrial & Engineering Chemistry Process Design and Development 25 (1), 252 - 265. https://doi.org/10.1021/i200032a041Rodriguez, C., September 2020. Revisiting the simplified imc tuning rules for low-order controllers: Novel 2dof feedback controller. IET Control Theory & Applications 14, 1700-1710(10). https://doi.org/10.1049/iet-cta.2019.0821Ruscio, D. D., 2010. On Tuning PI Controllers for Integrating Plus Time Delay Systems. 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Nutrition, diet and immunosenescence

Ageing is characterized by immunosenescence and the progressive decline in immunity in association with an increased frequency of infections and chronic disease. This complex process affects both the innate and adaptive immune systems with a progressive decline in most immune cell populations and defects in activation resulting in loss of function. Although host genetics and environmental factors, such as stress, exercise and diet can impact on the onset or course of immunosenescence, the mechanisms involved are largely unknown. This review focusses on identifying the most significant aspects of immunosenescence and on the evidence that nutritional intervention might delay this process, and consequently improve the quality of life of the elderly

Virgin olive oil phenolic compounds modulate the HDL lipidome in hypercholesterolaemic subjects: a lipidomic analysis of the VOHF study

Scope The lipidomic analysis of high-density lipoprotein (HDL) could be useful to identify new biomarkers of HDL function.Methods and results A randomized, controlled, double-blind, crossover trial (33 hypercholesterolaemic subjects) is performed with a control virgin olive oil (VOO), VOO enriched with its own phenolic compounds (FVOO), or VOO enriched with additional phenolic compounds from thyme (FVOOT) for 3 weeks. HDL lipidomic analyses are performed using the Lipidyzer platform. VOO and FVOO intake increase monounsaturated-fatty acids (FAs) and decrease saturated and polyunsaturated FAs in triacylglyceride (TAG) species, among others species. In contrast, FVOOT intake does not induce these FAs changes. The decrease in TAG52:3(FA16:0) after VOO intake and the decrease in TAG52:5(FA18:2) after FVOO intake are inversely associated with changes in HDL resistance to oxidation. After FVOO intake, the decrease in TAG54:6(FA18:2) in HDL is inversely associated with changes in HDL cholesterol efflux capacity.Conclusion VOO and FVOO consumption has an impact on the HDL lipidome, in particular TAG species. Although TAGs are minor components of HDL mass, the observed changes in TAG modulated HDL functionality towards a cardioprotective mode. The assessment of the HDL lipidome is a valuable approach to identify and characterize new biomarkers of HDL function.Proteomic