Search results for "Systems Engineering"
showing 10 items of 1230 documents
Temperature Rise Estimation of Induction Motor Drives Based on Loadability Curves to Facilitate Design of Electric Powertrains
2017
Thermal protection limits are equally important as mechanical specifications when designing electric drivetrains. However, properties of motor drives like mass/length of copper winding or heat dissipation factor are not available in producers’ catalogs. The lack of this essential data prevents the effective selection of drivetrain components and makes it necessary to consult critical design decisions with equipment's suppliers. Therefore, in this paper, the popular loadability curves that are available in catalogs become a basis to formulate a method that allows to estimate temperature rise of motor drives. The current technique allows for evaluating a temperature rise of a motor drive for …
General and flexible methodology and architecture for CAPP: GF-CAPP system
2003
Although all researchers insist on the need to develop computer-aided process planning (CAPP) systems, they agree that one of its most significant shortfalls is the low level of generality and flexibility present in current proposals. One of the outcomes of this low level of generality--apart from its limited application domain--is the low level of integration achieved with CAD, CAM and PP&C systems. To ensure optimized running of the production system, it is also important to stress the need to develop alternative process planning that enables it to adapt to disruptions in production. Several factors play an important role in implementing these features, among which the following may be hi…
Modeling Requirements for Future CASE
1995
In this paper we discuss some requirements for future CASE Computer Aided Software/Systems Engineering environments. These requirements include increased modifiability and flexibility as well as support for process and agent models. We claim that they can only be addressed by developing more powerful representation and modeling techniques. As a possible basis for modeling various techniques, we outline a general information architecture for a future CASE environment. In addition, we propose primitive types for specifying techniques, the development process, and agent models, and use these types for modeling an example methodology and examine how the requirements are or can be supported in o…
Process support in MetaCASE: implementing the conceptual basis for enactable process models in MetaEdit+
2002
This study concerns the support of information system analysis and design process in a metaCASE environment. We see a process as highly, evolutionary and unstructural in nature, thus requiring the tailorability of user process models and their conceptual basis, process modelling language (PML). In addition to the flexibility needed for guiding various system developers, the CASE environment needs to be enacted using strictly defined environment actions. A distinction between user and environment processes is made, hence distinguishing also their conceptual basis and modelling requirements. The study depicts the realisation of the basic concepts and tools required in modelling a PML and the …
Autonomous on-board data processing and instrument calibration software for the SO/PHI
2018
The extension of on-board data processing capabilities is an attractive option to reduce telemetry for scientific instruments on deep space missions. The challenges that this presents, however, require a comprehensive software system, which operates on the limited resources a data processing unit in space allows. We implemented such a system for the Polarimetric and Helioseismic Imager (PHI) on-board the Solar Orbiter (SO) spacecraft. It ensures autonomous operation to handle long command-response times, easy changing of the processes after new lessons have been learned and meticulous book-keeping of all operations to ensure scientific accuracy. This contribution presents the requirements a…
A stochastic approach for self-healing capability evaluation in active islanded AC/DC hybrid microgrids
2023
This paper aims to implement a resilience assessment in AC/DC hybrid microgrids using a stochastic simulation approach. Self-healing measures including load shedding, control of distributed generation and flexible devices, like Energy Storage Systems (ESS) and Electrical Vehicles (EVs), are simulated to enable AC/DC hybrid microgrids to supply critical loads in islanded mode, assuming a disconnection of these microgrids from the main AC grid due to a fault. To perform this analysis, a two-stage process is proposed: first, a Monte-Carlo simulation-based stochastic approach is adopted to generate samples to simulate intermittent loads, power generation from Renewable Energy Sources (RESs), an…
Gain sideband splitting in dispersion oscillating fibers
2014
International audience; We analyze the modulation instability spectrum in a varying dispersion optical fiber as a function of the dispersion oscillation amplitude. For large dispersion oscillations, we predict a novel sideband splitting into different sub-sidebands. The emergence of the new sidebands is observed whenever the classical perturbation analysis for parametric resonances predicts vanishing sideband amplitudes. The numerical results are in good quantitative agreement with Floquet or Bloch stability analysis of four-wave mixing in the periodic dispersion fiber. We have also shown that linear gain or loss may have a dramatic influence in reshaping the new sidebands.
Optimization of Long-Run Average-Flow Cost in Networks With Time-Varying Unknown Demand
2010
We consider continuous-time robust network flows with capacity constraints and unknown but bounded time-varying demand. The problem of interest is to design a control strategy off-line with no knowledge of the demand realization. Such a control strategy regulates the flow on-line as a function of the realized demand. We address both the case of systems without and with buffers. The main novelty in this work is that we consider a convex cost which is a function of the long-run average-flow and average-demand. We distinguish a worst-case scenario where the demand is the worst-one from a deterministic scenario where the demand has a neutral behavior. The resulting strategies are called min-max…
Objective function design for robust optimality of linear control under state-constraints and uncertainty
2009
We consider a model for the control of a linear network flow system with unknown but bounded demand and polytopic bounds on controlled flows. We are interested in the problem of finding a suitable objective function that makes robust optimal the policy represented by the so-called linear saturated feedback control. We regard the problem as a suitable differential game with switching cost and study it in the framework of the viscosity solutions theory for Bellman and Isaacs equations. © 2009 EDP Sciences, SMAI.
An EKF Based Method for Path Following in Turbulent Air
2017
An innovative use of the Extended Kalman Filter (EKF) is proposed to perform both accurate path following and adequate disturbance rejection in turbulent air. The tuned up procedure employs simultaneously two different EKF: the first one estimates gust disturbances, the second one estimates modified aircraft parameters. The first filter, by using measurements gathered in turbulent air, estimates both aircraft states and wind components. The second one, by using the estimated disturbances, obtains command laws that are able to reject disturbances. The predictor of the second EKF uses the estimated wind components to solve motion equations in turbulent air. Besides a set of unknown stability …