MIMO PID Controller Tuning Method for Quadrotor Based on LQR/LQG Theory

In this work, a new pre-tuning multivariable PID (Proportional Integral Derivative) controllers method for quadrotors is put forward. A procedure based on LQR/LQG (Linear Quadratic Regulator/Gaussian) theory is proposed for attitude and altitude control, which suposes a considerable simplification of the design problem due to only one pretuning parameter being used. With the aim to analyze the performance and robustness of the proposed method, a non-linear mathematical model of the DJI-F450 quadrotor is employed, where rotors dynamics, together with sensors drift/bias properties and noise characteristics of low-cost commercial sensors typically used in this type of applications are considered. In order to estimate the state vector and compensate bias/drift effects in the measures, a combination of filtering and data fusion algorithms (Kalman filter and Madgwick algorithm for attitude estimation) are proposed and implemented. Performance and robustness analysis of the control system is carried out by employing numerical simulations, which take into account the presence of uncertainty in the plant model and external disturbances. The obtained results show the proposed controller design method for multivariable PID controller is robust with respect to: (a) parametric uncertainty in the plant model, (b) disturbances acting at the plant input, (c) sensors measurement and estimation errors

Comparison between nested grids and unstructured grids for a high-resolution wave forecasting system in the western Mediterranean sea

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Journal of Operational Oceanography on 2017, available online at: http://www.tandfonline.com/10.1080/1755876X.2016.1260389Traditionally wave modelling uses a downscaling process by means of successive nested grids to obtain high-resolution wave fields near the coast. This supposes an uncertain error due to internal boundary conditions and a long computational time. Unstructured grids avoid multiple meshes and thus the problem of internal boundary conditions. In the present study high resolution wave simulations are analysed for a full year where high-resolution meteorological models were available in the Catalan coast. This coastal case presents sharp gradients in bathymetry and orography and therefore correspondingly sharp variations in the wind and wave fields. Simulations with SWAN v.4091A using a traditional nested sequence and a regional unstructured grid have been compared. Also a local unstructured grid nested in an operational forecast system is included in the analysis. The obtained simulations are compared to wave observations from buoys near the coast; almost no differences are found between the unstructured grids and the regular grids. Simultaneously, tests have been carried out in order to analyse the computational time required for each of the alternatives, showing a decrease to less than half the time when working with regional unstructured grids and maintaining the forecast accuracy and coastal resolution with respect to the downscaling system.Peer ReviewedPostprint (author's final draft

Multimode interference filter to solve degradation on coupler common-mode rejection

After quantifying degradation of a common mode rejection ratio (CMRR) 3dB-coupler due to excitation of TE01 mode, a novel compact circuit including multimode interference (MMI) coupler+bend+MMI+filter (CBF) is proposed. We show a CBF circuit has better CMRR at the expense of moderate loss. A complete tolerance analysis to main geometrical parameters has also been carried out.Publicad

Tripod-shaped penta (p-phenylene)s for the functionalization of silicon surfaces

In order to obtain nanostructured thin films to be used in biosensor devices, several chemical functionalization methods have been developed, such as Click chemistry or Suzuki carbon-carbon coupling reactions on surfaces.1 With the aim to control the orientation and spacing between grafted functional groups on a surface, tripodal oligo (p-phenylene)s have become the ideal anisotropic adsorbates due to their shape-persistent and self-standing characteristics.2 Here we report the synthesis and characterization of several tripod-shaped oligo(p-phenylene)s molecules with legs composed of five phenylene units, compounds 1, 2 and 3. In these structures, each leg is end-capped with an NH-Boc, NH2 and N3 group, respectively. The functional arm contains an acetylene group. The presented synthesis has as key step the Pd-catalyzed Suzuki cross-coupling reaction. In particular, a iodine derivative from the silicon core molecule reacts with the appropriate tetra(p-phenylene) boron derivative, thus generating the final tripod-shaped structure. The azide end-capped leg in 3 is specifically designed for its covalent incorporation on alkynyl terminated silicon surfaces by an easy and reproducible way. As a preliminary study, we present the alkynyl-functionalized silicon wafers nanostructuration with tripod 3 through the cooper catalyzed alkyne-azide cycloaddition (CuAAC) click reaction.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A Survey on Valdivia Open Question on Nikodým Sets

[EN] Let A be an algebra of subsets of a set W and ba(A) the Banach space of bounded finitely additive scalar-valued measures on A endowed with the variation norm. A subset B of A is a Nikodým set for ba(A) if each countable B-pointwise bounded subset M of ba(A) is norm bounded. A subset B of A is a Grothendieck set for ba(A) if for each bounded sequence in ba(A) the B-pointwise convergence on ba(A) implies its ba(A)*-pointwise convergence on ba(A). A subset B of an algebra A is a strong-Nikodým (Grothendieck) set for ba(A) if in each increasing covering {B_n : n \in N} of B there exists B_m which is a Nikodým (Grothendieck) set for ba(A). The answer of the following open question for an algebra A of subsets of a set W, proposed by Valdivia in 2013, has not yet been found: Is it true that if A is a Nikodým set for ba(A) then A is a strong Nikodým set for ba(A)? In this paper we surveyed some results related to this Valdivia¿s open question, as well as the corresponding problem for strong Grothendieck sets. The new Propositions 1 and 3 provide more simplified proofs, particularly in their application to Theorems 1 and 2, which were the main results surveyed. Moreover, the proofs of almost all other propositions are wholly or partially original.This research was funded by grant PGC2018-094431-B-I00 of Ministry of Science, Innovation and Universities of Spain for the second named author.López Alfonso, S.; López Pellicer, M.; Moll López, SE.; Sánchez Ruiz, LM. (2022). A Survey on Valdivia Open Question on Nikodým Sets. Mathematics. 10(15):1-11. https://doi.org/10.3390/math10152660111101

Effects of Learning from Distributors on Manufacturers’ Exploitation and Exploration Innovation Strategies in Food and Beverages Industry

The relevance of innovation as source of competitive advantage is clearly justified in the literature (Adner and Kapoor, 2010; Song and Thieme, 2009). In particular, knowledge, as well as all items related to organizational learning, represents a main factor contributing to the innovation success (i.e., Song and Parry, 1997). In this sense, different authors have emphasized the importance that external sources of knowledge possess for the development and success of the innovation capability (Li and Tang, 2010; Spithoven et al., 2010).The globalization of manufacturing companies is closely linked to the globalization of distribution activities (Mattsson, 2003). It can be said that globalization of retailers drives globalization of manufacturing companies. So the latter will be influenced by the supply conditions of the target markets, the possibilities to supply new markets, or the possible threat to be replaced by alternative suppliers (Ruiz, 2000, Etemad, 2004).At the same time, supply chains have progressively become more international and complex (Monczka and Trent, 2005), representing principal sources of competitive advantage in terms of availability of technological and organizational competencies and access to minor operative costs (Pagano, 2009). The international supply tends increasingly to be considered as a strategic tool chasing to take advantage of the previous advantages. Consequently, organizations should promote this critical organizational relational capability (Kotabe and Murray, 2004)

Program development using abstract interpretation (and the ciao system preprocessor)

The technique of Abstract Interpretation has allowed the development of very sophisticated global program analyses which are at the same time provably correct and practical. We present in a tutorial fashion a novel program development framework which uses abstract interpretation as a fundamental tool. The framework uses modular, incremental abstract interpretation to obtain information about the program. This information is used to validate programs, to detect bugs with respect to partial specifications written using assertions (in the program itself and/or in system librarles), to genérate and simplify run-time tests, and to perform high-level program transformations such as múltiple abstract specialization, parallelization, and resource usage control, all in a provably correct way. In the case of validation and debugging, the assertions can refer to a variety of program points such as procedure entry, procedure exit, points within procedures, or global computations. The system can reason with much richer information than, for example, traditional types. This includes data structure shape (including pointer sharing), bounds on data structure sizes, and other operational variable instantiation properties, as well as procedure-level properties such as determinacy, termination, non-failure, and bounds on resource consumption (time or space cost). CiaoPP, the preprocessor of the Ciao multi-paradigm programming system, which implements the described functionality, will be used to illustrate the fundamental ideas

Felicidad, bienestar subjetivo y satisfacción en la sociedad gallega

Estudio sobre la evolución de los indicadores de bienestar subjetivo (felicidad) en la sociedad gallega y sus determinante

Does Corruption Have Social Roots? The Role of Culture and Social Capital

[Abstract:] The aim of this work is to analyse the influence of sociocultural factors on corruption levels. Taking as starting point Husted (J Int Bus Studies 30:339–359, 1999) and Graeff (In: Lambsdorff J, Taube M, Schramm M (eds) The new institutional economics of corruption. Routledge, London, 2005) proposals, we consider both the interrelation between cultural dimensions and the diverse expressions of social capital with corruption. According to our results, the universalistic trust (linking and bridging social capital) constitutes a positive social capital that is negatively linked to corruption. In contrast, the particularistic levels of trust (bonding) can constitute a negative social capital directly related to corruption levels. Furthermore, cultures which are favourable to the legitimation of dependency relations and the formation of closed particularistic groups (power-distance and community factors) create a breeding ground for the development of these amoral rent-seeking structures