Stochastic model predictive control of LPV systems via scenario optimization

A stochastic receding-horizon control approach for constrained Linear Parameter Varying discrete-time systems is proposed in this paper. It is assumed that the time-varying parameters have stochastic nature and that the system's matrices are bounded but otherwise arbitrary nonlinear functions of these parameters. No specific assumption on the statistics of the parameters is required. By using a randomization approach, a scenario-based finite-horizon optimal control problem is formulated, where only a finite number M of sampled predicted parameter trajectories (‘scenarios') are considered. This problem is convex and its solution is a priori guaranteed to be probabilistically robust, up to a user-defined probability level p. The p level is linked to M by an analytic relationship, which establishes a tradeoff between computational complexity and robustness of the solution. Then, a receding horizon strategy is presented, involving the iterated solution of a scenario-based finite-horizon control problem at each time step. Our key result is to show that the state trajectories of the controlled system reach a terminal positively invariant set in finite time, either deterministically, or with probability no smaller than p. The features of the approach are illustrated by a numerical example

Residual Stress in Friction Stir Welding and Laser-Assisted Friction Stir Welding by Numerical Simulation and Experiments

The friction stir welding (FSW) has become an important welding technique to join materials that are difficult to weld by traditional fusion welding technology. In this technique, the material is not led to fusion, and the joint is the result of the rotation and movement along the welding line of the tool that causes softening of material due to frictional heat and the stirring of the same. In FSW, the temperature does not reach the fusion value of the materials, and this helps to decrease the residual stress values. However, due to the higher force involved in the weld and, thus, the rigid clamping used, the residual stresses are not low in general in this technique. As the presence of high residual stress values influences the post-weld mechanical properties, e.g. fatigue properties, it is important to investigate the residual stress distribution in the FSW welds. In this chapter, two numerical models that predict temperatures and residual stresses in friction stir welding and laser-assisted friction stir welding will be described. Experimental measurements of temperatures and residual stress will be carried out to validate the prediction of the models

First data on batch fecundity and relative fecundity of Sardina pilchardus (Walbaum, 1792) (Clupeidae) in the south-western Adriatic Sea

Se ha determinado por primera vez la fecundidad parcial y relativa de Sardina pilchardus (Walbaum, 1792) en las aguas del bajo Adriático con el método de los ovocitos hidratados. Las muestras han sido recogidas de la propia flota comercial y de embarcaciones alquiladas y equipadas con red de arrastre pelágico a la pareja, red de arrastre semipelágico a la pareja o red de cerco con jareta durante el periodo de reproducción. Se han estudiado diferentes modelos de regresión entre la fecundidad parcial y el peso de las hembras sin ovarios. El mejor ajuste corresponde a una regresión lineal. Se ha calculado también la fecundidad relativa (número de ovocitos por gramo de hembra sin ovarios) y se ha confrontado con la de otros clupeiformes.The batch fecundity and relative fecundity of Sardina pilchardus (Walbaum, 1792) have been determined for the first time in the waters of the Lower Adriatic Sea using the hydrated oocyte method. The samples were collected from the commercial fleet and chartered boats equipped with midwater pair trawls, midwater otter trawls and purse seine during the reproductive period. Various regression models were studied, to express the relationship between the batch fecundity and the weight of ovary-free females. The linear model proved to be the best one, because of its simplicity. Relative batch fecundity (number of hydrated oocytes per gram from ovary-free females) was also studied, and compared with that of other clupeiforms.Instituto Español de Oceanografí

Theoretical advances on Economic Model Predictive Control with time-varying costs

© 2016 Published by Elsevier Ltd on behalf of International Federation of Automatic Control.Economic Model Predictive Control is a technique for optimization of economic revenues arising from controlled dynamical processes that has established itself as a variant of standard Tracking Model Predictive Control. It departs from the latter in that arbitrary cost functions are allowed in the formulation of the stage cost. This paper takes a further step in expanding the applicability of Economic Model Predictive Control by illustrating how the paradigm can be adapted in order to accommodate time-varying or parameter-varying costs

Corrosion Resistance Behaviour of recycled AlSi10Mg alloy: Surface Morphology and Acoustic Emission Investigation

The corrosion resistance behaviour of recycled AlSi10Mg alloy prepared using Selective Laser Melting (SLM) process is investigated. The specimens are exposed to salt solution attack (5% NaCl) atomized in uniform droplets, inside a controlled Salt Spray Test (SST) chamber for 1000 h. The surface morphology of the specimens exposed to different predefined exposure times (0 h, 6 h, 48 h, 168 h, 480 h and 1000 h) are investigated under Scanning Electron Microscope (SEM). The SEM micrographs shows the salient features of the corrosion attack such as the formation both of pits and corrosion products on samples surface in different exposure times in the SST chamber. Similarly, the Acoustic Emission (AE) signals generated during the corrosion process are recorded for the different exposure times. The AE waveforms are studied using advanced waveform processing techniques. The waveforms, in their time-frequency domain, provide detailed information on the characteristic features of the acoustic source. The different AE sources have been characterized from the time-frequency analysis of the waveforms

METRO - The role and future perspectives of Cohesion Policy in the planning of Metropolitan Areas and Cities. Annex III: Metropolitan City of Turin case study

The Metropolitan City of Turin, which is one of the case studies of the ESPON METRO project, is a wide area, second level local authority which replaced the former Province of Turin from January 1st, 2015. The metropolitan institution brings together 312 municipalities, covering a very large and heterogeneous territory, from dense urban areas to small towns and villages, much larger than the functional urban area of Turin. It is the largest metropolitan city in Italy, fourth in population size (2.2Mln inhabitants) and seventh in population density (330 inh/km2). Metropolitan Cities are administrative units formally established in Italy by the reform of local authorities (National Law 56/2014), replacing the respective Province authorities. The Italian Metropolitan cities still perform all the functions of the previous Province authorities, and have additional functions, such as strategic, spatial and mobility planning, organization of coordinated systems for the management of public services, mobility and transport, promotion and coordination of digitalization and economic and social development. Despite the high level of institutionalization and competences of the Metropolitan City of Turin, which is formally acknowledged as an entity also enjoying a supranational relevance when it comes to access EU funds, the institution does not have relevant role and competences in the elaboration of key policy and programming documents of the EU cohesion policy and in their management and implementation, while the Region and the national level are the main actors. In this case study report, the potential and actual role of the Metropolitan City of Turin in the implementation of the cohesion policy, and the impact of the cohesion policy on metropolitan development and governance are analysed. After a territorial and socio-economic contextualization of the area, the metropolitan governance and cooperation activities are presented. Then, the cohesion policy institutional architecture and policy instruments are presented, and the role of the metropolitan actors in the planning and implementation of the cohesion policy is examined, as well as its coordination with metropolitan governance. The cohesion policy impact on metropolitan development and governance is then presented, analyzing the coherence and synergies of its instruments and goals with metropolitan ones, the funding magnitude and the related impact. Issues related to the response to the COVID-19 emergency are presented in each of the three core sections of the report. Finally, the last section of the report summarizes the main challenges and recommendations

Intermittent predictive control of an inverted pendulum

Intermittent predictive pole-placement control is successfully applied to the constrained-state control of a prestabilised experimental inverted pendulum