Experimental Analysis of RSSI-based Indoor Location Systems with WL Circularly Polarized Antennas

Circularly polarized antennas are used in 2.4 GHz ZigBee radio modules to evaluate performance improvement of RSSI (Received Signal Strength Indicator) based location techniques, with respect to conventional linearly polarized antennas. Experimental RSSI measurements in an indoor environment clearly show that multipath fading is significantly reduced when CP antennas are used; this determines a more reliable estimation of the field amplitude decay law as a function of the distance of the mobile node from the fixed access point, and then a higher location accuracy. At the best of authors' knowledge, it is the first time that the circular polarization features are applied to RSSI-based radio location techniques

Multidisciplinary approach for developing a new robotic system for domiciliary assistance to elderly people

This paper aims to show the effectiveness of a (inter / multi)disciplinary team, based on the technology developers, elderly care organizations, and designers, in developing the ASTRO robotic system for domiciliary assistance to elderly people. The main issues presented in this work concern the improvement of robot’s behavior by means of a smart sensor network able to share information with the robot for localization and navigation, and the design of the robot’s appearance and functionalities by means of a substantial analysis of users’ requirements and attitude to robotic technology to improve acceptability and usability

On the design, development and experimentation of the ASTRO assistive robot integrated in smart environments

This paper presents the full experience of designing, developing and testing ASTROMOBILE, a system composed of an enhanced robotic platform integrated in an Ambient Intelligent (AmI) infrastructure that was conceived to provide favourable independent living, improved quality of life and efficiency of care for senior citizens. The design and implementation of ASTRO robot was sustained by a multidisciplinary team in which technology developers, designers and end-user representatives collaborated using a user-centred design approach. The key point of this work is to demonstrate the general feasibility and scientific/technical effectiveness of a mobile robotic platform integrated in a smart environment and conceived to provide useful services to humans and in particular to elderly people in domestic environments. The main aspects faced in this paper are related to the design of the ASTRO’s appearance and functionalities by means of a substantial analysis of users’ requirements, the improvement of the ASTRO’s behaviour by means of a smart sensor network able to share information with the robot (Ubiquitous Robotics) and the development of advanced human robot interfaces based on natural language

Single Scans of Ti-6Al-4V by Directed Energy Deposition: A Cost and Time Effective Methodology to Assess the Proper Process Window

Directed energy deposition is an additive manufacturing technology which usually relies on prototype machines or hybrid systems, assembled with parts from different producers. Because of this lack of standardization, the optimization of the process parameters is often a mandatory step in order to develop an efficient building process. Although, this preliminary phase is usually expensive both in terms of time and cost. The single scan approach allows to drastically reduce deposition time and material usage, as in fact only a stripe per parameters combination is deposited. These specimens can then be investigated, for example in terms of geometrical features (e.g. growth, width) and microstructure to assess the most suitable process window. In this work, Ti-6Al-4V single scans, produced by means of directed energy deposition, corresponding to a total of 50 different parameters combinations, were analyzed, focusing on several geometrical features and relative parameters correlations. Moreover, considering the susceptibility of the material to oxygen pick-up, the necessity of an additional shielding gas system was also evaluated, by comparing the specimens obtained with and without using a supplementary argon flow. A process window, which varies according to the user needs, was found together with a relationship between microstructure and process parameters, in both shielding scenarios

An investigation on the effect of different multi-step heat treatments on the microstructure, texture and mechanical properties of the DED-produced Ti-6Al-4V alloy

This work deals with the effect of different heat treatments on directed energy deposition (DED)-produced Ti- 6Al-4V samples. Annealing treatments at 1050 ◦C followed by different cooling rates were conducted to allow a complete recrystallization of the microstructure and remove the columnar prior-β grains, thus increasing the overall isotropy of the material. An agine treatment at 540 ◦ C was also performed for further microstructural stabilization. The microstructures, textures and mechanical properties were then assessed. Due to the heat treatments, greatly differing microstructures were achieved in an equiaxed grain morphology. However, a “grain memory” effect was detected which resulted in the grains size increasing along the height of the samples. This effect was correlated to the intrinsic prior-β grain width variation along Z on the as-printed specimens, typical of the DED technology. Electron backscatter diffraction analyses proved that the intensity of the preferential di- rections increased after the heat treatments, likely due to the crystallographic variant selection mechanisms taking place when the samples cool down from the annealing temperature. This effect is also influenced by the significant difference in terms of prior-β grains sizes between the heat-treated and the as-printed specimens. To sum up, a complete homogenization of the material via heat treatment above the β-transus temperature proved to be challenging. In fact, the data suggest that the intrinsic texture-related anisotropy granted by the manufacturing process is very difficult to be eliminated

Ambient Assisted Living and Ageing: Preliminary Results of RITA Project

The ageing of population is a social phenomenon that most of worldwide countries are facing. They are, and will be even more in the future, indeed trying to find solutions for improving quality of life of their elderly citizens. The project RITA wants to demonstrate that an update of the current socio-medical services with an Ambient Assisted Living (AAL) approach could improve the service efficiency and the quality of life of both elderly and caregiver. This paper presents the preliminary results obtained in RITA

A two DoF finger for a biomechatronic artificial hand

Current prosthetic hands are basically simple grippers with one or two degrees of freedom, which barely restore the capability of the thumb-index pinch. Although most amputees consider this performance as acceptable for usual tasks, there is ample room for improvement by exploiting recent progresses in mechatronics design and technology. We are developing a novel prosthetic hand featured by multiple degrees of freedom, tactile sensing capabilities, and distributed control. Our main goal is to pursue an integrated design approach in order to fulfill critical requirements such as cosmetics, controllability, low weight, low energy consumption and noiselessness. This approach can be synthesized by the definition "biomechatronic design", which means developing mechatronic systems inspired by living beings and able to work harmoniously with them. This paper describes the first implementation of one single finger of a future biomechatronic hand. The finger has a modular design, which allows to obtain hands with different degrees of freedom and grasping capabilities. Current developments include the implementation of a hand comprising three fingers (opposing thumb, index and middle) and an embedded controller