2021 ◽  
Vol 22 (12) ◽  
pp. 625-633
Author(s):  
A. V. Zuev ◽  
A. N. Zhirabok ◽  
V. F. Filaretov ◽  
A. A. Protsenko

The paper is devoted to the problem of fault identification in technical systems described by non-stationary nonlinear dynamic equations under unmatched disturbances. To solve the problem, sliding mode observers are used. The suggested ap- proach is based on the model of the original system of minimal dimension having different sensitivity to the faults and distur- bances in contrast to the traditional approaches to sliding observer design which are based on the original system. Additionally it is assumed that matrices describing such a model have the canonical form and are constant. The main purpose of using such a model is possibility to take into account the non-stationary feature of the systems. As a result, the model has stationary dynamic and non-stationary additional term that allows to promote sliding mode design. Besides, the new approach to design sliding mode observers is suggested. The peculiarity of this approach is that it does not require that original systems should be minimum phase and detectable. According to the traditional approaches stability of the observer is provided by minimum phase and detectability properties. In our approach, stability of the observer is achieved due to the canonical form of the matrices describing the model. In addition, the matching condition is not necessary. This allows to extend a class of systems for which sliding mode observers can be designed. Theoretical results are illustrated by practical example of electric servoactuator.


2009 ◽  
pp. 79-116
Author(s):  
Gianni Bianco ◽  
Pierluigi Cecati

- Water will be a basic problem in the future of the world. At the moment in Italy the main problem lies in water reserve reductions facing a growing demand, while for drinkable water more and more administrator authorities are facing a budget deficit. The causes of this national and local situation are the administrative monopoly and the absence of planning and coordination policies, that would rationalize water use without rationing it, starting from an awareness of the costs of different involved variables. The economic quality of spring and consumption water, the oldness of the waterworks and pipe networks, the extreme fragmentation of waterworks (often of minimal dimension), their territorial localisation, the absence of a common method of charges, the scanty use of analysis of management, are some of the causes of a unique and surprising variability of costs, proceeds and tariffs. This paper analyzes the generation and the structure of the costs of drinkable water in an area representative of many national characteristics on the environmental, physic and socio-economic level. The quest for more efficient forms of management and for a more transparent determination of the tariffs has been carried on through the use of custom indexes of productivity and of production. These indexes summarise the existence of scale economies, of pipe network related diseconomies, and of economies of localisation and density of the consumers. The paper presents a synthesis of the observations gathered from about two hundred waterworks subdivided by owner and entrepreneurial typologies


2019 ◽  
Vol 2019 (1) ◽  
pp. 000152-000156 ◽  
Author(s):  
Roman Ostholt ◽  
Rafael Santos ◽  
Norbert Ambrosius ◽  
Daniel Dunker ◽  
Jean-Pol Delrue

Abstract The objective of this paper is to demonstrate the feasibility of glass mounting substrates made by Laser Induced Deept Etching (LIDE) technology, which include newly developed passive die alignment structures. The aim of these structures is to compensate for potential die misalignments and die shift issues which become severe when moving to panel level fan-out packaging. The passive alignment structures are located at two adjacent edges of the rectangular cavity and are created in the same process step as the open cavities. The filigree spring-like alignment structures benefit from being processed in a crack- and stress-free manner. Although the spring elements have a minimal dimension of less than 100 μm, these structures show an outstanding break strength while deformed when active dies are placed in the mounting cavity. Depending on the design, the spring elements can have a stroke of several tenths of micrometer which enable the compensation of rather large die displacements. Here, we present examples for LIDE-processed mounting glass substrates with the described features. The performance of the proposed design and method was evaluated with a die accuracy study. Test dies with alignment marks were placed in the cavities and measured relatively to alignments marks on the mounting glass substrate. The Fan-Out packaging concept based on the research shown here combines several advantages: due to the relatively high Young's modulus of the glass, the reconstituted wafer shows less warpage than in the state-of-art; while the passive alignment structures reduce the die shift to a minimum (depending on dicing accuracies and through package vias for package-on-package or antenna-in-package application), and can be readily integrated.


Author(s):  
Sigrid Leyendecker ◽  
Sina Ober-Blo¨baum ◽  
Jerrold E. Marsden ◽  
Michael Ortiz

This paper formulates the dynamical equations of mechanics subject to holonomic constraints in terms of the states and controls using a constrained version of the Lagrange-d’Alembert principle. Based on a discrete version of this principle, a structure preserving time-stepping scheme is derived. It is shown that this respect for the mechanical structure (such as a reliable computation of the energy and momentum budget, without numerical dissipation) is retained when the system is reduced to its minimal dimension by the discrete null space method. Together with initial and final conditions on the configuration and conjugate momentum, the reduced time-stepping equations serve as nonlinear equality constraints for the minimisation of a given cost functional. The algorithm yields a sequence of discrete configurations together with a sequence of actuating forces, optimally guiding the system from the initial to the desired final state. The resulting discrete optimal control algorithm is shown to have excellent energy and momentum properties, which are illustrated by two specific examples, namely reorientation and repositioning of a rigid body subject to external forces and the reorientation of a rigid body with internal momentum wheels.


2020 ◽  
Vol 171 ◽  
pp. 105175 ◽  
Author(s):  
Timothy C. Burness ◽  
Martino Garonzi ◽  
Andrea Lucchini

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