6 research outputs found

    Development and validation of wear models by using innovative three-dimensional laser scanners:

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    One of the main problems in railway and tramway systems, both dynamically (safety, comfort etc.) and economically (planning of maintenance interventions, reduction of wheel and rail lifetime etc.), is represented by the wear of wheel and rail profiles, due to the wheel–rail interaction. The profile's shape variation caused by wear influences the dynamic behaviour of the vehicle and, in particular, the wheel–rail contact conditions. Hence, nowadays, one of the most important topics in the railway field is the development of reliable wear models to predict profiles evolution, together with the use of more efficient and accurate measuring instruments for the model validation and the rolling components inspection. In this context, the aim of this research work is the development and the validation of wear models, using experimental data acquired through an innovative measuring instrument based on noncontact three-dimensional laser scanning technology. The tramway line of the city of Florence, characterized by very narrow curves and critical in terms of wear, has been chosen as a reference test case. Moreover, the inspection procedures currently adopted on this line for the maintenance plan are based only on classical two-dimensional contact measurement systems, not so accurate for a complete wear assessment. Therefore, the introduction of a new three-dimensional laser scanning technology may have a great impact on the maintenance management of the line

    The DressGripper: A Collaborative Gripper With Electromagnetic Fingertips for Dressing Assistance

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    This letter introduces a collaborative gripper designed for safe interactions during wearing operations. In a robotic system helping people to get dressed, two main goals have to be achieved: i) the gripper that potentially comes in contact with the person has to be intrinsically safe and ii) the gripper should be able to keep the cloth during dressing, e.g. while passing the arm inside the sleeve of a jacket. This letter proposes the DressGripper, a gripper that addresses these issues by combining a compliant and safe structure with an additional magnetic actuation at the fingertips. This combination enables a soft interaction with the robot while guaranteeing the necessary grasping tightness. Experiments with the proposed prototype demonstrate its applicability in robotic dressing assistance scenarios

    Performance indices for motorsport drivers analysis

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    The present paper aims to propose performance indices able to characterize the driving abilities of a car driver in the motorsport ambit. These indices could be used both to improve drivers performances and to conduct comparative analyses between professional and non-professional drivers. The data used for the analysis come from a Formula 4 vehicle and have been acquired by means of a specific data logger. Some indices, suggested by the specific literature in the motorsport vehicles, have been analyzed and employed on the data acquired on track during races. The results were not so satisfactory especially to evaluate the performance of a non-professional driver. The proposed indicators defined as the product of the accelerations along one determined direction (longitudinal or lateral) for the corresponding velocities seem to be suitable to be used as performance indices for the pilot in all the three main phases of a curve. The analysis of the data shows that these indices are quite reliable even if, in some particular cases, they show little discrepancies. This happens because the indices must be interpreted differently in dependence of the various types of curve, which are diversely approached (e.g. a chicane or a hairpin). Further development will improve the indicators according to the type of curve, trying to give an overall performance indicator for each curve
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