Development of a knee prosthesis powered by electro-hydrostatic actuation

L'abstract è presente nell'allegato / the abstract is in the attachmen

The admission experience survey italian version (I-AES). a factor analytic study on a sample of 156 acute psychiatric in-patients

Coercive treatments are often regarded as an inevitable and yet highly debated feature of psychiatric care. Perceived coercion is often reported by patients involuntarily committed as well as their voluntary counterparts. The Admission Experience Survey (AES) is a reliable tool for measuring perceived coercion in mental hospital admission. We developed the Italian AES (I-AES) through translation back-translation and administered it to 156 acutely hospitalized patients (48% women, 69% voluntarily committed) in two university hospitals in Rome (Policlinico Umberto I, Sant'Andrea Hospital). A principal component analysis (PCA) with equamax rotation was conducted. The I-AES showed good internal consistency (Cronbach's alpha = 0.90); Guttmann split-half relia- bility coefficient was 0.90. AES total score significantly differed between voluntary and involuntary committed patients (5.08 ± 4.1 vs. 8.1 ± 4.9, p < .05). PCA disclosed a three-factor solution explaining 59.3 of the variance. Some discrepancies were found between the factor structure of the I-AES and the original version. I- AES total score was positively associated with numbers of previous involuntarily hospitalization (r = 0.20, p < .05) and psychiatric symptoms' severity (r = 0.22, p < .02). I-AES and its proposed new factor structure proved to be reliable to assess perceived coercion in mental hospital admission. Consequently, it may represent a helpful instrument for the study and reduction of patients' levels of perceived coercion

UAV powertrain efficient design through a modelbased approach

The wide spreading market of unmanned aerial vehicles (UAVs) is requiring more and more performing flying platforms. For rotary wing systems, especially multicopters, the leading design challenge is the powertrain, typically composed (for mini and small UAVs) by: battery, electronic speed controllers, electrical motors and propellers. A strong knowledge in terms of these subsystems behaviour in their operative conditions is required. Therefore, through a careful design and modelling of these subsystems, it is possible to achieve higher overall efficiency, lighter systems, and consequently, an increased flight endurance. Unfortunately, current literature and available datasheets on UAV components, especially electric motors and propellers, are scattered and not reliable. The present work proposes a model-based design methodology: motor and propeller equivalent analytical models are presented; then – in order to identify model parameters, tune them and shade some doubts about the reliability of available data – two test benches have been developed. The first one allows to characterize the electric motors varying the torque load condition, while the second is devoted to propellers thrust and torque characterization. Models and identified parameters have been validated by comparing the expected results with in-flight endurance experiments

Analysis & Modelling of Powertrain Components for an Efficient UAV Design

In the design of an unmanned aerial vehicle (UAV), one crucial problem is the flight autonomy of the overall system. The powertrain of electric UAVs, namely: battery, electronic speed controllers, motors and propellers has been analysed to evaluate their effect on the efficiency of the system, and thus the autonomy. Current literature and datasheets on UAV performances, especially on electric motor and propeller, are usually scattered and poor. Two different test benches have been developed to characterize speed controllers, motors and propellers; experimental results have been used to tune motor-propeller numerical models. The proposed work allowed to shade some doubts about the reliability of the available data and validate a model-based design methodology

Design Methodology of Gerotor Hydraulic Machines for Mechatronic Applications

In mechatronic applications such as electro-hydrostatic actuators, gerotor machines are often preferred over other technologies due to their high efficiency, low wear, low noise, and compactness. The design approach for hydraulic machines, either for motoring or pumping applications, involves the definition of different geometrical parameters, which affect their performance. Thus, the designer is often left without a clear design method to adopt. In this perspective, the presented research aims at providing a general design methodology of gerotor machines for their integration into high-efficiency mechatronic devices. In particular, the study focuses on the analytical and numerical characterization of the optimal tooth aspect ratio and maximum eccentricity between gears. Indeed, these two features are often left to the experience of the designer or are selected with empirical formulations. Our method is validated by means of numerical data from computational fluid-dynamic models to assess the performance of the hydraulic units