Recent results in tilt control design and assessment of high-speed railway vehicles

Active tilt control is a well-established technology in modern railway vehicles, for which currently used control approaches have evolved in an intuitive matter. This paper presents work on a set of novel strategies for achieving local tilt control, i.e. applied independently for each vehicle rather than the whole train precedence approach that is commonly used. A linearized dynamic model is developed for a modern tilting railway vehicle with a tilt mechanism (tilting bolster) providing tilt below the secondary suspension. It addresses the fundamental problems associated with straightforward feedback control, and briefly discusses the current industry norm, which employs command-driven with precedence strategy. Two new advanced schemes are proposed, a model-based estimation approach, and an optimal LQG-based approach, and compared to the command-driven with precedence. The performance of the control schemes is assessed through simulation using a new proposed assessment method

Optimised sensor configurations with reduced order controllers applied to an EMS system

In many applications, sensor selection in an optimum sense is not a trivial task, especially when a number of objectives and constraints are to be satisfied simultaneously. Moreover, for practical implementation the order of the synthesized controller could be a burden of increased cost and complexity. In this paper, a systematic framework for optimum sensor selection is considered which considers issues of controller reduction. Efficacy of the proposed framework is illustrated via simulations on an Electro-Magnetic Suspension (EMS) system

Supply-chain modelling and control under proportional inventory-replenishment policies

A novel state-space model of a multi-node supply chain is presented, controlled via local proportional inventory-replenishment policies. The model is driven by a stochastic sequence representing customer demand. The model is analysed under stationarity conditions and a simple recursive scheme is developed for updating its covariance matrix. This allows us to characterise the ‘bullwhip effect’ (demand amplification) in the chain and to solve an optimisation problem for a three-node model involving the minimisation of inventory subject to a probabilistic constraint on downstream demand. Finally, issues related to estimation schemes based on local historical data are briefly discussed

La plaza de mercado como Noduarticulador : espacio intermodal, la Mesa - Cundinamarca

The paper studies the utilisation of model reduction techniques, both physical-based and mathematicalbased, in designing simplified LQG optimal tilt controllers to improve the curving performance of railway coaches at increased running speed. The schemes make exclusive use of local practical signal measurements, i.e. sensors mounted on the current passenger coach. The fundamental problem related with straightforward classical nulling-feedback control is presented, while the commercially-used command-driven with precedence scheme is introduced. A combination of simulation results and, a recently proposed, tilt control system assessment method are employed for assessing the performance of the designed LQG controller

A new educational software tool for robust control design using the QFT method

We present a new educational software tool for robust control design based on the Quantitative Feed back Design (QFT) method. This is a graphical design methodology for systems with large parametric uncertainty, which has been successfully applied to many complex practical problems. The software tool is implemented in Matlab and may be used to introduce students to robust control methods via small and medium-size design applications. The software is a library of programmable h1-files with open access to users and is intended as a test-bed for developing new techniques in this area and for automating parts of the design procedure, such as loopshaping. A simple design problem is used to illustrate the main features of the software