1,721,056 research outputs found
Loudness calculation procedure to study electronic steering column lock noise measurement
Full text linkIn the automotive field, the customer requirements for low interior noise and pleasant sound quality inside a vehicle are getting higher and higher. Various national and international regulatory authorities established and reviewed vehicle inte- rior noise for the past years. Besides, lots of studies have shown that vehicle noise can influence the driver’s perceptions and also his or her driving capabilities. To succeed in this scenario, all manufacturers are investing in technology and research in order to improve their component performance. Working on the noise source so as to reduce the serious- ness of these noise problems can be really effective. However, various engineering techniques are available to deal with noise and sound-measuring instruments, and systems can help to identify the nature of the problem and they can also be helpful in determining the right procedure to analyse the noise problem. This work proposes a procedure to evaluate the noise originated from an electronic steering column lock device which is used to lock and unlock the steering wheel according to European safety requirements. In particular, different standards and requirements for loudness evaluation have been discussed and the formulation of a straightforward procedure, which can be used to evaluate the loudness according to costumer’s requirements, is defined
Three-Fingered Gripper with Flexure Hinges Actuated by Shape Memory Alloy Wires
No full textA three-fingered gripper with flexure hinges actuated by shape memory alloy (SMA) wires was designed and prototyped. The aim of the work was the manipulation of small, almost cylindrical objects, e.g. test tubes, by a device having small overall dimensions. A parametric study of four different, but similar, fingers was conducted with the aim of obtaining a solution with a good amplification ratio and a gripping force almost constant during closure. The use of flexure hinges simplifies the design, but limits the finger range of motion. Moreover, it was possible to find a configuration with sufficient work space. Once the finger geometry was defined, the whole hand was then designed with the aim of producing a compact hand contained in a cylindrical volume (d 65 x h 65 mm), and the first prototype was built. Preliminary tests demonstrated its good dimensioning and the success of some technological solutions. The experimental transmission ratio was almost the same as the theoretical one. Some drawbacks have been highlighted, such as a reduced range of motion and incomplete backstroke; future studies will deal with them
Modello matematico di sistemi intermittenti per uso terapeutico
No full textLa compressione pneumatica intermittente (IPC) è una tecnica utilizzata per vari trattamenti terapeutici, quali il recupero sportivo, il linfodrenaggio, la prevenzione della trombosi profonda. A seconda dell’applicazione, le caratteristiche di funzionamento di un dispositivo IPC possono essere molto differenti e difficili da valutare a priori, per cui è solitamente necessaria una fase di ottimizzazione basata su regolazioni prevalentemente empiriche. La realizzazione di un modello matematico in grado di simulare l’interazione tra il dispositivo e l’essere umano consente un approccio ingegneristico alla progettazione e messa a punto del sistema
Experimental testing of a modular flexible actuator based on sma wires
Full text linkA flexible finger made up of three actuator modules based on shape memory wires (SMA) is experimentally studied in this research. A module is composed by few simple components: a plastic body and SMA wires. The body is a thin cylinder with a lower and upper base and two intermediate disks. Three equidistant SMA wires are longitudinally placed and allow the module to bend in any direction when one or more wires are actuated. The motion of the module is performed with the heating and cooling of the wire and the central rod exerts bias force, necessary to the stretching of the wire to the original length. Two test benches were built to perform both positioning tests and force tests. To evaluate the actuator workspace different tests were performed, with different power supply, heating and cooling time, actuation sequence. Force tests were performed with different distance between the undeformed finger and the obstacle. The results achieved with this first prototype are encouraging since the finger shows stable and correct operation. The planar projection of the workspace is a circle of about 30-40 mm of radius and exerted force is similar to mathematical model results (about 1 N at 5 mm). These results are encouraging, even though, probably due to manufacturing imperfections and frictions, the movement is not very regular along the various directions
Ortesi per la riabilitazione cardiocircolatoria
No full textQuando una persona è costretta in maniera prolungata o definitiva all’immobilità degli arti inferiori, viene a mancare l’azione di “pompa muscolare” che durante la deambulazione contribuisce al ritorno del sangue venoso al cuore. Questo può produrre importanti effetti sul sistema cardiocircolatorio, come ad esempio l’insorgenza di patologie cardiache nei paraplegici o una importante diminuzione delle capacità aerobiche in atleti che praticano sport di resistenza.
E’ possibile cercare di compensare tale insufficienza tramite l’applicazione di un dispositivo pneumatico che, esercitando un’adeguata azione meccanica su piedi e gambe, favorisca il ritorno del sangue venoso al cuore
Applicazioni di ventose in robotica mobile
No full textLe ventose sono un utile strumento, leggero ed economico, per consentire l’adesione a pareti o soffitti di robot arrampicatori. L’utilità di questi ultimi risulta evidente in particolare in situazioni in cui l’intervento umano è rischioso o costoso. In questi ultimi anni vari ricercatori hanno sviluppato dispositivi che permettono l’intervento per la pulizia, l’ispezione, la manutenzione in differenti ambienti. Sebbene non vi sia ancora un largo uso di questi robot, sono state poste le premesse per una loro futura ampia diffusione
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