1,721,120 research outputs found
Simulation and experimental tests of a safety braking system for aerial tramways
No full textAerial tramways are a fast and efficient mean of transportation, especially found in mountainous regions where the ability of clearing steep inclines makes them a preferred solution. Often non-autonomous, these types of cabin have little or no power installed and thus must be drawn by the haulage rope. In case of failure, a safety braking system must prevent the cabin from rolling back along the track rope. The braking system under investigation is a fail-safe device composed by two braking units that clamp the track rope in case of failure. The aim of the present study was to estimate the braking time. Given the complexity and costs related to on-field experimental tests, simulations and laboratory tests were carried out. The braking unit was modelled in MSC ADAMS, making use of the MSC ADAMS/Hydraulics plug-in. Simulations and experiments were in a very good agreement, evidencing the system’s compliance to Italian regulation
Modelling and simulation of mechanical systems driven by electro-hydraulic actuators
No full textIl lavoro tratta la fase di modellazione e simulazione di un sistema meccanico pilotato da azionamenti oleodinamici.Uno degli aspetti più interessanti caratterizzanti il lavoro è lo sviluppo di un modello completo del sistema, in cui le due parti fondamentali, quella meccanica e quella oleodinamica, non vengono trattate distintamente ma viene eseguita una simulazione in cui si tiene conto delle influenze che una parte di sistema ha sull’altra.Inoltre, l’adeguatezza del modello sviluppato viene valutata mediante un confronto con dati sperimentali disponibili, dimostrando una buona corrispondenza con i risultati delle simulazioni
Theoretical - experimental analysis of periodic running machines driven by aysnchronous motor fed by inverter
No full textValvole direzionali proporzionali: quadro generale
No full textLe valvole direzionali proporzionali hanno avuto una crescente diffusione nell'industria manifatturiera e nel settore mobile a partire da metà degli anni '70. Da allora esse hanno avuto un'evoluzione piuttosto complessa, per cui oggi il panorama di tali valvole è molto ampio e una loro classificazione non è semplice. Scopo di questo articolo è fornire un quadro generale organico, mantenendo, per quanto possibile, caratteristiche di semplicità e brevità
Driving Technologies for the Design of Additive Manufacturing Systems
Full text linkThe Additive Manufacturing (AM) technology, belonging to the most comprehensive Net Shape Forming family, has in recent years a growing trend due to the increasing quality of the built product. These results may open the application of the AM to the industrial field, moving the application from laboratories to the plant floor. This step requires machines capable of executing the technology process of AM with the requirements of the industrial environment, concerning as example the production speed, reliability, robustness, and process stability. The design of such type of machinery requires a systematic and multidisciplinary approach for reaching these industrial targets. Indeed the AM process involves several design technological issues, like temperature control of the material to be processed, characteristics of the energy source for material transition, control of the power transferred to the material, scanning system’s head control, 3D model’s layer definition, generation of the laser point’s trajectories. The final product’s quality strongly depends on all these aspects synergically linked each other, as well as on the technical solutions to realize them. The paper presents an interdisciplinary approach to the design of machines for AM, based on the Powder Bed Fusion process, and targeted to the industrial field. The technological platforms discussed in the paper are essential for such type of machines. The strategy proposed constitutes a base reference point for the definition of a methodological approach to the design of AM machinery
Analisi fluidodinamiche di valvole direzionali proporzionali
No full textPer una simulazione accurata del comportamento di una valvola direzionale proporzionale occorre effettuare la modellazione degli elementi che la costituiscono. In particolare è anche necessario conoscere l'interazione tra la spola e il fluido, sia in condizioni stazionarie sia dinamiche. A questo scopo è stato realizzato un banco prova che permette di determinare sperimentalmente come la forza agente sulla spola e la portata dipendono dall'apertura della valvola e dalla caduta di pressione sul carico
A novel in field method for determining the flow rate characteristics of pneumatic servo axes
No full textSeveral strategies, in order to improve an actuator’s control and to increase the bandwidth, consider the relationship between the valve’s driving signal and the air flow rate. Such an approach to the control strategy takes advantage of the evaluation of the valve’s characteristic parameter, known as sonic conductance. The sonic conductance can be measured following the procedure stated by the standard ISO 6358. Nevertheless, the measurement carried out according to this standard is very expensive in terms of time and air consumption. In this paper, an alternative method to evaluate the sonic conductance is presented. The method is based on a new practical approach: the sonic conductance is evaluated leaving the valve mounted on the actuator and using only the piston’s position transducer. The steady state piston’s motion allows us to determine the sonic conductance. The new approach allows us to get the conductance in a very short time, without the need to use a proper test bench and pressure transducers. Moreover, performing the measurements directly on the pneumatic axis allows us to characterize not only the valve but the duct connecting the valve to the actuator’s chamber too
Analisi Fluidodinamiche di Valvole direzionali proporzionali
No full textPer una simulazione accurata del comportamento di una valvola direzionale proporzionale occorre effettuare la modellazione degli elementi che la costituiscono. In particolare è anche necessario conoscere l'interazione tra la spola e il fluido, sia in condizioni stazionarie sia dinamiche. A questo scopo è stato realizzato un banco prova che permette di determinare sperimentalmente come la forza agente sulla spola e la portata dipendono dall'apertura della valvola e dalla caduta di pressione sul carico
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