An Underactuated Multi-finger Grasping Device

In this paper, a mechanical model for an underactuated multi-finger grasping device is presented. The device has single-tendon, three-phalanx fingers, all moved by only one actuator. By means of the model, both the kinematic and dynamical behaviour of the finger itself can be studied. The finger is part of a more complex mechanical system that consists of a four-finger grasping device for robots or a five-finger human hand prosthesis. Some results of both the kinematic and dynamical behaviour are also presented

A New Real Time Shape Acquisition with a Laser Scanner: First Test Results

Abstract The first results of a new method for real-time shape acquisition with a laser scanner are presented. The new method is essentially based on the use of a laser beam and a web-cam. A digital filter parameters identification was studied for the laser line detection in the image. After this, a model for the reconstruction in real-time of the laser line in the space was developed. The firsttest rig was just conceived to validate the method; hence, no high resolution cameras were adopted. Nevertheless, the tests have showed encouraging results. Tests were made on both plane and non-plane surfaces. First of all, it was confirmed that it is possible to calibrate the intrinsic parameters of the video system, the position of the image plane and the laser plane in a given frame, all in the same time. Moreover the surface shapes were recognized and recorded with an appreciable accuracy. The tests also showed that the proposed method can be used for robotic applications, such as robotic kinematic calibration and 3D surfaces recognition and recording. For this last purpose, the test rig is fitted on a robot arm that permits to the scanner device to ‘observe’ the 3D object from different and known positions

Robot Assisted 3D Shape Acquisition Optical Systems

In this chapter, a short description of the basic concepts about optical methods for the acquisition of three-dimensional shapes is first presented. Then two applications of the surface reconstruction are presented: the passive technique Shape from Silhouettes and the active technique Laser Triangolation. With both these techniques the sensors (telecameras and laser beam) were moved and oriented by means of a robot arm. In fact, for complex objects, it is important that the measuring device can move along arbitrary paths and make its measurements from suitable directions. This chapter shows how a standard industrial robot with a laser profile scanner can be used to achieve the desired d-o-f. Finally some experimental results of shape acquisition by means of the Laser Triangolation technique are reported

Robot assisted 3D shape acquisition by optical systems

In this chapter, a short description of the basic concepts about optical methods for the acquisition of three-dimensional shapes is first presented. Then two applications of the surface reconstruction are presented: the passive technique Shape from Silhouettes and the active technique Laser Triangolation. With both these techniques the sensors (telecameras and laser beam) were moved and oriented by means of a robot arm. In fact, for complex objects, it is important that the measuring device can move along arbitrary paths and make its measurements from suitable directions. This chapter shows how a standard industrial robot with a laser profile scanner can be used to achieve the desired d-o-f. Finally some experimental results of shape acquisition by means of the Laser Triangolation technique are reported

Epidermal Growth Factor Modulates Fetal Thymocyte Growth and Differentiation

In the present study, we used the fetal organ culture (FTOC) technique in order to study a putative effect of epidermal growth factor (EGF) on the thymus ontogeny. Functional EGF receptors and more recently the EGF molecule itself, respectively, on the membrane of epithelial components of thymic stroma and on a few thymocytes in adult thymus, had been reported in the literature. We could observe a dose-dependent decrease in cellularity and a progressive retention of thymocytes in the double-negative (CD4-/CD8-) stage of differentiation when exogenous EGF was added. Epidermal growth factor interfered with both fetal stroma growth and thymocyte development at a precise moment, that is, in the passage from double-negative to the double-positive (CD4+/CD8+) stage. After a 7-day FTOC in the presence of EGF, most cells recovered were Thy-1.2+, c-kit+, TSA1-/int, CD3-, and one of CD44high/CD25int, CD44-/CD25int, or CD44-/CD25-. Some developed into γδTCR+ cells with a mature (CD3+) phenotype, but not into αβTCR+ thymocytes. It seems that EGF addition makes the cultures "nonpermissible" for αβTCR+ thymocyte generation. We report here the presence of a high Mr "EGF-like" molecule on the membrane of fetal thymocytes, which role in the observed effects is under investigation. Further biochemical characterization of this molecule is still required, because its presence was only evidenced on the basis of its antigenicity

EXPERIENCES OF AUTOMATED CARTOGRAPHIC GENERALIZATION IN ITALY: TECHNIQUES AND RESULTS OF THE CARGEN PROJECT

La generalizzazione automatica è un campo di ricerca attivo da ormai oltre trenta anni. Recentemente il costante progresso delle tecniche e il miglioramento dei risultati ha portato all'introduzione di procedure di derivazione automatica all'interno dei processi produttivi di alcuni enti cartografici europei. Questo articolo illustra lo stato della ricerca nel campo della generalizzazione cartografica automatica in Italia e mostra come anche nel nostro paese si stiano conseguendo risultati significativi; in particolare verranno descritti i progressi del progetto CARGEN, che studia la derivazione alla scala 1:25000 e 1:50000 del DBT nazionale.The achievements in the field of automated cartographic generalization have recently lead to the actual deployment of automatic processes in the production workflow of some European NMAs. This article describes the state of the research on automated cartographic generalization in Italy, focusing in particular on the results of the CARGEN project, studying the generalization of the National DBT to the 1:25000 and 1:50000 scales

AN UNDERACTUATED MECHANICAL HAND PROSTHESYS BY IFToMM ITALY

This paper describes a mechanical underactuated hand, whose design is under patenting. The proposed hand can be used as robot grasping end-effector and, mainly, as a human prosthesis. The proposed underactuated mechanism is based on an adaptive scheme, hence it permits to move five fingers with only one actuator. The actuator is connected to a set of pulleys that operate five tendons. Each tendon will move the phalanxes of a finger. The proposed mechanism permits each finger to adapt its configuration to almost any object shape so that each of the fingers will grasp the object independently on the configuration of the finger itself and independently on the configuration of the other fingers. The tendons are un-extendible so that each finger will grasp an object always with the same force, regardless of object shape. The overall grasping force will be controlled just by adjusting the input actuator torque. This paper also reports preliminary kinematic and dynamic studies aiming to a validation of the feasibility of the proposed design solution. Finally an early experimental prototype is shown

Spontaneous thrombosis of primary external jugular veins aneurysms

External jugular vein (EJV) aneurysms represent a rare condition whose origin, evolution and consequent best therapeutic options still need further investigations. We present herein two peculiar clinical cases. In the first one, an EJV aneurysm developed around a malformed valve which embedded a spontaneous thrombosis. Transverse cutaneous nerve compression by the aneurysmatic mass was identified. In the second case, a recurring thrombosed EJV aneu - rysm was found pinched among the platysma muscle and the superficial layer of the cervical fascia. A pertinent literature review is also presented in order to interpret the findings herein never previously described

Short endovenous laser ablation of the great saphenous vein in a modified CHIVA strategy

Mini-invasiveness, ease of use and execution speed represent the reasons for endovenous laser ablation success. Nevertheless, the strategic choice remains the ablation of the saphenous trunk. Hemodynamic correction (CHIVA) represents an option, based on a saphenous-sparing therapeutic strategy. We tested the feasibility of a modified CHIVA strategy by means of endovenous lasers (EL) shrinkage of segmental great saphenous vein (GSV) tracts, in networks characterized by sapheno-femoral incompetence and re-entry perforators focused on the GSV. We report the follow up of the first 2 chronic venous disease [C1,2,3sEpAsPr1,2,3, venous clinical severity score (VCSS) 8 and 9 respectively] treated cases. At 1-year follow up both patients were C1,2,3sEpAsPr1,2,3 and the VCSS were 1 and 2 respectively. The non-treated GSV tracts maintained their patency. ELs were herein used within a saphenous-sparing therapeutic plan, thanks to an accurate pre-operative hemodynamic assessment, which allowed the shrinkage of only the first saphenous trunk tract only. Proper technical and hemodynamic considerations are discussed