395 research outputs found
Wearable robotics [From the Guest Editors]
No full textThe articles in this special section discusses advancements made in the area of wearable robots and reports on the many applications for their use
Analysis of a gas supply unit based on hydrogen peroxide decomposition for wearable robotic applications
No full textWith the aim of developing new solutions for powering pneumatic actuators in the field of wearable robotics, a principle scheme of a pressurized gas supply unit (GSU) based on hydrogen peroxide decomposition is proposed and a dynamic mathematical model is developed to simulate its operation. In the application scenario considered for the simulations, the GSU feeds a pneumatic ankle prosthesis during a standard daily living at-home activity. Furthermore, experiments of hydrogen peroxide decomposition on manganese dioxide powder have been carried out in an apparatus that partially mimics the behavior of the GSU. The results show that the GSU proposed is suitable for the implementation in a mobile robotic system, and, more in general, the use of the hydrogen peroxide decomposition process as a gas source for pneumatic actuators can be a viable approach to solve the principal issues related to powering wearable robotic devices. © 2013 American Chemical Society
Low-temperature H2O2-powered actuators for biorobotics: Thermodynamic and kinetic analysis
No full textThe need for novel, high performance actuators felt in several fields of robotics, such as assistive or rehabilitative robotics, is not fully satisfied by current actuation means. This fosters an intense research on novel energy transduction methods. In particular, propellant-based chemical actuators, able to directly convert chemical energy into mechanical energy, appear very promising, although their potential in robotics has not yet been deeply investigated. This work focuses on H2O2, used as propellant for actuators. This chemical was first used in robotics, with excellent results, by Goldfarb and collaborators, in 2003. H2O 2 dissociation is strongly exothermic, which generates important design issues when the actuated machine operates in close proximity to the human body. In this paper it is shown that: 1) is possible to operate the decomposition process at acceptable temperature, by means of basic solutions of hydrogen peroxide; 2) for basic pH solutions, tin becomes an effective catalyst for H2O2 dissociation. A kinetic model of H 2O2 dissociation in basic solutions is provided, that is in good agreement with experimental data. We show how the model can be used to gather the necessary information for the dimensioning of H2O 2-based actuators. ©2010 IEEE
A microfabricated physical sensor for atmospheric mercury monitoring
No full textAbstract A new microfabricated physical sensor for elemental gaseous mercury (Hg 0 ) determinations has been developed and experimentally tested by the authors. Hg 0 represents 90-99% of atmospheric mercury forms. The sensor is based on the technique of resistivity variation of thin gold film, characterised by high selectivity and absence of optical parts. The sensor consists of four identical thin gold film resistors mounted in Wheatstone bridge configuration. Two resistors work as sensitive elements and the others as reference, in order to minimise the influence of temperature variation. The absorption of Hg 0 on the gold film produces a change in the resistivity of the amalgam. Far from the saturation, this change is proportional to the amount of the absorbed Hg 0 . The adsorption behaviour of the sensor deposited by sputtering on two different substrates (glass and Printed Circuit Board (PCB)) have been investigated. The sensors showed to work in a large range of linearity and need a low power during the regeneration process. Sensors on glass and PCB substrates underwent numerous regeneration cycles without inflicting any mechanical or electrical damages to the resistors. The presented experimental results describe the features of both sensors pointing out advantages and drawbacks of the used substrates. The PCB substrate seems to have more suitable characteristics for developing a new mercury 'smart' sensor
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