Wilber Acuña B - Academia.edu (original) (raw)

Papers by Wilber Acuña B

Plants

Araucaria heterophylla needles were collected in urban areas of the city of Quito, Ecuador, to an... more Araucaria heterophylla needles were collected in urban areas of the city of Quito, Ecuador, to analyze the relationship between the concentration of polycyclic aromatic hydrocarbons (PAHs) with different emission sources and road characteristics. The PAHs were analyzed by high-performance liquid chromatography (HPLC) and included naphthalene (Naph), benzo[a]anthracene (BaA), chrysene (Chry), and benzo[a]pyrene (BaP), which are related to the sources considered in this work. The results indicated that some streets with moderate and low traffic intensity had higher total concentrations of PAHs than streets with high traffic intensity, showing the importance of non-traffic related emission sources and road characteristics on PAH emissions. All the studied PAHs were associated with traffic emissions, although Naph and BaP were more associated with acceleration and braking activities, while BaA and Chry also seemed to come from restaurant emissions. The presence of gas stations was also ...

An approach for implementation of control system with anti-windup compensation using fault detect... more An approach for implementation of control system with anti-windup compensation using fault detection multifiltering is presented. The residual signal used for anti-windup compensation is obtained from a filter bank (i.e. multifiltering) for fault detection, thus it is not necessary its explicit measurement. This residual signal is considered as a fault, in order to design the fault detection filter. The filter bank is synthesized using robust LMI based control techniques. Additional LMI restrictions have been used in the optimization process, to garantice better performance. This method allows to consider multiobjective performance indexes, for different actuator saturation conditions, in the same way as in fault diagnosis problems. A numerical example to probe the proposed implementation method effectiveness is also presented.

Advances in Automation and Robotics Research

Revista Técnica de la Facultad de Ingeniería Universidad del Zulia

En esta contribución, se presenta un esquema para la implementación práctica de la ganancia de co... more En esta contribución, se presenta un esquema para la implementación práctica de la ganancia de compensación anti-windup, tomando como base un sistema de diagnóstico y detección de fallas. Para ello, la saturación en los actuadores es considerada como una falla en el ...

2015 34th Chinese Control Conference (CCC), 2015

Hierarchical control architecture is a common to hydraulic systems. This paper outlines the appli... more Hierarchical control architecture is a common to hydraulic systems. This paper outlines the application of a modelbased 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.

The paper addresses sensor bias calibration when only differential bias is of interest as in rela... more The paper addresses sensor bias calibration when only differential bias is of interest as in relative calibration of different sensors. Temperature sensors are considered. Relative calibration is of interest in control problems where precise thermal gradients must be generated, or uniform and stable temperatures must be guaranteed. Static (or steady-state) and dynamic calibration are compared both theoretically and experimentally. Dynamic calibration has the advantage of employing any available measurement, but requires to dispose of a suitable dynamic model of the calibration equipment. A simple equipment with three sensors is considered in the paper, but the results can be extended to more complex ones. A further advantage is to perform calibration on any apparatus with the constraint (used in the paper) that the dynamic model is of the same order as the sensor size. Identifiability conditions are proved. Calibration is obtained through a nonlinear Weighted Least Squares problem, ...

In the propulsive phase, after parachute release, of planetary landing like Mars or Moon horizont... more In the propulsive phase, after parachute release, of planetary landing like Mars or Moon horizontal motion, horizontal motion is obtained by tilting the axial thrust, so that it aligns either to the negative velocity vector (gravity turn) or to the requested acceleration vector. The latter strategy is assumed here, as it allows pinpoint landing. As such, tilt angles (pitch and yaw) become proportional to the horizontal acceleration. Instead of designing a hierarchical guidance and control in which horizontal acceleration becomes the attitude control target, a unique control system can be designed based on the fourth order dynamics from angular acceleration to position. The paper shows that the combined dynamics can be (quasi) input-state linearized except the nonlinear factor of the tilt angles (the axial thrust imposed by vertical braking), and other less severe flaws. The paper shows that control design around the reference trajectory (tilt and position) given by the guidance can ...

18th Mediterranean Conference on Control and Automation, MED'10, 2010

This paper deals with the dynamic modeling, subsequent control design and testing of a complex el... more This paper deals with the dynamic modeling, subsequent control design and testing of a complex electro-hydraulic system. Modeling is based on physical laws and system knowledge. The main idea is to obtain a simple and reliable model that can be used for controller synthesis and implementation. Model reduction is done by using singular perturbation concepts. The power saving task required

Revista Iberoamericana de Automática e Informática Industrial RIAI, 2008

Proceedings of the 17th IFAC World Congress, 2008, 2008

This paper presents a novel technique for robust fault detection, based on a modified H 2 /H ∞ pe... more This paper presents a novel technique for robust fault detection, based on a modified H 2 /H ∞ performance condition, which is described as LMI. Some theoretical results are shown in order to synthesize the residual generation scheme, for systems subjected to parametric uncertainty. The uncertainty parameters are supposed to belong to a polytope. The extended H 2 /H ∞ conditions are obtained by means of the well known projection lemma. Fault detection and isolation are done by using a filters bank (i.e. multifiltering) based on Luenberger's observer and one filter is obtained for each fault. Performance of the proposed synthesis technique is illustrated by a numerical example.

2009 IEEE Conference on Emerging Technologies & Factory Automation, 2009

This paper deals with the dynamic modelling and subsequent control design and testing of a comple... more This paper deals with the dynamic modelling and subsequent control design and testing of a complex electro-hydraulic system. Modelling is based on physical laws and system knowledge. The main idea is to obtain a simple and reliable model that can be used for controller synthesis and implementation. A subsequent controller design procedure is made by using the architecture of embedded

2008 16th Mediterranean Conference on Control and Automation, 2008

This contribution presents a novel approach for robust fault detection and isolation in continuou... more This contribution presents a novel approach for robust fault detection and isolation in continuous-time and discrete-time linear systems based-on modified H2/Hinfin performance conditions, which are described as LMIs. In order to synthesize the residual signals, some theoretical results for systems with perturbation signals and subjected to parametric uncertainty are shown. The uncertainty parameters are supposed to belong to a polytope.

2013 IEEE International Conference on Mechatronics and Automation, 2013

ABSTRACT Proportional electro-hydraulic valves are ubiquitous as flow actuators in hydraulic syst... more ABSTRACT Proportional electro-hydraulic valves are ubiquitous as flow actuators in hydraulic systems. Flow regulation is the result of the accurate positioning of a spool driven by a solenoid and a position sensor. The overall control consists of two hierarchical 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 an accurate positioning of the spool with respect to the valve openings. The paper addresses the outer loop and concentrates on the conversion of an industrial analogue controller into a digital one. The analogue controller is a nonlinear proportional, integrative and derivative controller including a second-order derivative, and is capable of recovering a dead-band hysteresis. The digital conversion provides the necessary derivatives through a state predictor, in order to withstand the 5-kHz Nyquist limit of the power supplier. The digital control law is fed by state predictions and repeats the analogue control law with some improvement. Preliminary experiments prove that the conversion repeats and improves analogue performance. Some flaws of the resulting digital controller are outlined and discussed in view of a model-based conversion.

Robust control design is devoted to guarantee closed-loop stability of a model-based control law ... more Robust control design is devoted to guarantee closed-loop stability of a model-based control law in presence of parametric uncertainties. The control law is usually a static feedback law which is derived from a model. Under this view stability can only be guarantee by introducing some ignorance coefficients and restricting the feedback control effort with respect to the model-based design. Embedded

International Journal of Mechatronics and Automation, 2014

Proportional electro-hydraulic valves are ubiquitous as flow actuators in hydraulic systems. Flow... more Proportional electro-hydraulic valves are ubiquitous as flow actuators in hydraulic systems. Flow regulation is the result of the accurate positioning of a spool driven by a solenoid and a position sensor. The overall control consists of two hierarchical loops: the inner loop is the solenoid current regulator with a closed-loop bandwidth close to 1 kHz. A modelbased digital regulator of this kind has been presented elsewhere. The outer loop is a position tracking control, in charge of an accurate positioning of the spool with respect to the valve openings. The paper addresses the outer loop and concentrates on the conversion of an existing industrial analogue controller into a digital one. The analogue controller is a nonlinear proportional, integrative and derivative controller including a second-order derivative, and is capable of recovering a deadband hysteresis. The digital conversion provides the necessary position derivatives through a state predictor, in order to withstand the 5-kHz Nyquist limit of the power supplier. As such it departs from traditional conversions dating back to more than ten years ago. The digital control law is fed by the state predictions and repeats the analogue control law with some improvements, as shown by the reported experiments.

International Journal of Mechatronics and Automation, 2013

to data reduction of the European astrometric mission Hipparcos. Technological studies in view of... more to data reduction of the European astrometric mission Hipparcos. Technological studies in view of scientific and drag-free space missions, like Gaia and GOCE provided the opportunity of applying Embedded Model Control to drag-free satellites and to electrooptics. He contributed to the conception, design and implementation of the Nanobalance interferometric thrust-stand, capable of sub-micronewton accuracy. Presently he is involved in the design of the orbit, formation and attitude control of the Next Generation Gravity Missions of the European Space Agency. His research interests cover all the entire field of control problems that are challenging because of complexity, uncertainty and precision.

2009 American Control Conference, 2009

This paper deals with the dynamic modelling of a complex electro-hydraulic system. Modelling is b... more This paper deals with the dynamic modelling of a complex electro-hydraulic system. Modelling is based on physical laws and the system knowledge. The main idea is to obtain a simple and reliable model that can be used for controller synthesis and implementation by using the architecture of Embedded Model Control. Simplifications are made by taking as basis the ideas of singular perturbation. A subsequent identification procedure is made in order to acquire some important parameters, required for carrying out a simulation.

2012 IEEE International Conference on Mechatronics and Automation, 2012

ABSTRACT The paper formulates the error loop as a tool for designing robust stability control sys... more ABSTRACT The paper formulates the error loop as a tool for designing robust stability control systems in front of structured and unstructured uncertainties. The error loop indicates that a tool for accommodating such uncertainties is the noise estimator, which is the unique feedback channel from plant to control. It is shown that causality constraint in cancelling causal uncertainties (unknown disturbance) makes control law to play a role, offering a further degree of freedom. Employing asymptotic expansions of the closed-loop transfer functions, simple and explicit design formulae derive from stability inequalities: they relate closed-loop eigenvalues to model parameter and requirements. A simple example is provided from a ball and beam plant.