Zaragoza, Spain
Zaragoza, Spain

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Ramirez-Laboreo E.,University of Zaragoza | Sagues C.,University of Zaragoza | Llorente S.,BSH Home Appliances Group
IEEE Transactions on Industrial Electronics | Year: 2016

Contact bounce is probably the most undesirable phenomenon of electromagnetic switches. It reduces the performance of relays and contactors and is directly related to some of the processes that result in the destruction of the device. In this paper, a complete formulation of the problem is provided and a new strategy inspired by Runto- Run control is presented for reducing contact bounce. The method, which makes use of the repetitive functioning of these systems, is highly versatile and may be applied to different switches under diverse operating conditions. In addition, it is able to deal with changes during the service life of the device, such as plastic deformations or the erosion of the contacts. Several experimental results are included to prove the effectiveness of the method. © 1982-2012 IEEE.


Paesa D.,University of Zaragoza | Franco C.,University of Zaragoza | Llorente S.,BSH Home Appliances Group | Llorente S.,University of Zaragoza | And 2 more authors.
IEEE Transactions on Industry Applications | Year: 2011

The goal of this paper is twofold. First, we aim at investigating the potentials of reset observers (ReOs) applied to process control. Second, we aim to overcome the existing performance limitations of the temperature control in domestic cookers. To this end, we present an adaptive simmering control for induction cookers, whose parameters are updated online, depending on the estimates provided by a multiple-model ReO (MMReO). This new observer results in extending the idea of multiple models to the state observer framework. The MMReO consists of a reinitialized ReO and of multiple fixed identification models. The resultant control scheme satisfies the user requirements such as quick heating up, accurate temperature control, and fast disturbance rejection, outperforming previous results. Moreover, the proposed control scheme reduces energy consumption, and consequently, it can increase the efficiency of the whole cooking process. Additionally, a fixed robust quantitative feedback theory (QFT)-based controller is designed, and it is also used for comparison purposes. Several verification tests are carried out in real induction hobs to emphasize the effectiveness of our proposal compared with the QFT-based controller. © 2011 IEEE.


Franco C.,University of Zaragoza | Paesa D.,BSH Home Appliances Group | Lopez-Nicolas G.,University of Zaragoza | Sagues C.,University of Zaragoza | Llorente S.,BSH Home Appliances Group
IEEE International Conference on Intelligent Robots and Systems | Year: 2012

This paper is focused on dynamic coverage control with a team of robots. In this framework, decentralized control algorithms have been investigated to deal with the efficient coordination of the resources. The main contribution is a novel global strategy based on a hierarchical grid decomposition of the domain. This decomposition allows an ordered coverage of the domain that combined with a gradient based control law of the local error, achieves a better performance than previous approaches of dynamic coverage. The total coverage of the domain is proven, and the good performance of the approach is supported with simulations. © 2012 IEEE.


Sanz-Serrano F.,University of Zaragoza | Sagues C.,University of Zaragoza | Llorente S.,BSH Home Appliances Group
Applied Thermal Engineering | Year: 2016

The heating uniformity of the cooking vessels in domestic stoves depends on the type of heat source (induction, electric resistance, gas burner, etc.) and of the way in which the power is transferred to the pan. The evaluation of the stove functionalities is currently carried out by the manufacturers with costly experimental tests with real food, which are an important phase of the design process for the improvement of their performance in the food elaboration. In order to help to design the cookers and avoid the expensive tests, it is interesting to know how the heating power is distributed in each situation, so that the cookers can be adapted to obtain a more uniform heating. The contribution of this work is an inverse thermal model for the three aforementioned technologies of domestic cookers, which allows the calculation of the power distribution generated in the bottom of the pan from the measurement of the surface temperature. The results show that the proposed inverse model is of interest in many practical situations and can be used under diverse conditions. © 2015 Elsevier Ltd. All rights reserved.


Ramirez-Laboreo E.,University of Zaragoza | Sagues C.,University of Zaragoza | Llorente S.,BSH Home Appliances Group
Applied Thermal Engineering | Year: 2016

In this paper, a new heat and mass transfer model for an electric oven and the load placed inside is presented. The developed model is based on a linear lumped parameter structure that differentiates the main components of the appliance and the load, therefore reproducing the thermal dynamics of several elements of the system including the heaters or the interior of the product. Besides, an expression to estimate the water evaporation rate of the thermal load has been developed and integrated in the model so that heat and mass transfer phenomena are made interdependent. Simulations and experiments have been carried out for different cooking methods, and the subsequent energy results, including energy and power time-dependent distributions, are presented. The very low computational needs of the model make it ideal for optimization processes involving a high number of simulations. This feature, together with the energy information also provided by the model, will permit the design of new ovens and control algorithms that may outperform the present ones in terms of energy efficiency. © 2015 Elsevier Ltd. All rights reserved.


Sanz-Serrano F.,University of Zaragoza | Sagues C.,University of Zaragoza | Llorente S.,BSH Home Appliances Group
IEEE Industry Application Society - 51st Annual Meeting, IAS 2015, Conference Record | Year: 2015

In this paper, we propose a theoretical model of multiple-coil inductors supplied by resonant half-bridge inverters in induction hobs. The model includes coupling effects and allows calculating the coil currents and the inverter's output power for any modulation parameters, even with different switching frequencies and duty cycle. Furthermore, we calculate the power distribution in the pan and obtain the relationship with the output powers of the power stage, so that they can be controlled to obtain a homogeneous power distribution and a more uniform heating. © 2015 IEEE.


Ramirez-Laboreo E.,University of Zaragoza | Sagues C.,University of Zaragoza | Llorente S.,BSH Home Appliances Group
IEEE Industry Application Society - 51st Annual Meeting, IAS 2015, Conference Record | Year: 2015

In this paper, a novel multiphysics and nonlinear model for electromechanical relays is presented. The electromagnetic dynamics is analyzed by calculating the total reluctance of the magnetic equivalent circuit, which is composed of a fixed length iron core and an angular air gap. Magnetic saturation and angular dependency of the reluctance are considered in the calculation. Then, an energy balance applied to the electromagnetic components of the system is used to obtain the torque which acts on the movable armature. A planar mechanism of four rigid bodies, including spring-damping torques that restrict the motion and model the contact bounces that occur in the switchings, is proposed to explain the dynamics of the movable components. Experimental tests show the accuracy of the model both in the electromagnetic and the mechanical parts. © 2015 IEEE.


Sanz-Serrano F.,University of Zaragoza | Sagues C.,University of Zaragoza | Llorente S.,BSH Home Appliances Group
Lecture Notes in Business Information Processing | Year: 2016

The heating uniformity of a domestic cooker is decisive for good results of the food elaboration. In this work we present the use of the inverse thermal modelling for the calculation of the power distribution transferred from a domestic cooker to the pan. The most common cooking stoves (induction, electric resistance and gas), have been used. The proposed method, using a rectangular thin metallic piece and an infrared camera, improves the accuracy and reduces the computational cost with respect to previous works. Moreover, it can help to improve the design process of cookers, providing more reliable results than current methods based in experimental tests with real food. © Springer International Publishing Switzerland 2016.


Franco C.,University of Zaragoza | Lopez-Nicolas G.,University of Zaragoza | Sagues C.,University of Zaragoza | Llorente S.,BSH Home Appliances Group
Proceedings of the IEEE Conference on Decision and Control | Year: 2013

In this paper we tackle the problem of persistent coverage, where a team of agents covers an area whose amount of coverage degrades with time. The task is never accomplished completely due to the coverage decay and the agents have to revisit the domain persistently. In this framework, our contribution is a novel approach which consists not only in developing efficient motion to perform the coverage, but also in covering the domain with a variable coverage action. The agents can adapt its coverage power to the coverage error of the actuator domain, being able to reduce the energy consumption and the coverage error. We propose a new controller for the coverage power and we demonstrate by means of simulations that it is more efficient and flexible than developing the coverage with constant power. © 2013 IEEE.


Palacios-Gasos J.M.,University of Zaragoza | Montijano E.,Centro Universitario Of La Defensa Cud | Sagues C.,University of Zaragoza | Llorente S.,BSH Home Appliances Group
Proceedings of the American Control Conference | Year: 2016

In this paper we tackle the persistent coverage problem, that aims to maintain a desired coverage level in an environment. The difference with traditional coverage resides in that the coverage decays over time and the robots must keep continuously moving to maintain the desired level. In this context we consider a cost function that quantifies the quality of the coverage in a finite prediction horizon and transform the persistent coverage problem into a discrete optimization problem with constraints. We introduce a branch-and-bound algorithm that allows us to find the optimal solution to the problem, i.e., the set of actions that minimizes the cost function. This algorithm includes a procedure to split the sets of candidate solutions and the calculation of upper and lower bounds on the cost. Additionally, we propose a method to reduce the problem to several smaller subproblems. Finally, we carry out simulations to evaluate the performance of the system. © 2016 American Automatic Control Council (AACC).

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