1,721,263 research outputs found
Одна теорема об n-мерном преобразовании Лапласа
No full text[Dahiya R. S.; Дахия Р. С.]English. Bulgarian, Russian summar
Development of fingertip tactile sensing chips for humanoid robots
No full textThis paper presents the development of tactile sensing
chips, for the fingertips of humanoid robots. In the first phase of
development, piezoelectric polymer-MEA (microelectrode array)
based test chips have been realized. Each chip comprises of 32
microelectrodes, epoxy-adhered with a thin piezoelectric polymer
(PVDF-TrFE) film. The diameter of each microelectrode or
'taxel' (tactile element) is 500 11m and the center to center
distance between taxels is 1 mm. The tactile sensing chips have
been experimentally evaluated over a wide range (0.02 - 4N or - 2
gmf- 400 gmt) of dynamic normal forces and frequencies (2 Hz -
5 KHz) by applying variable force with constant frequency in the
first case and constant force with variable frequency in latter.
The cross-talk, among adjacent taxels on the chips, is found to be
approximately 20%. Finally, the ability of the chips to identify
object material on the basis of their hardness is also
demonstrated
System Approach: A paradigm for Robotic Tactile Sensing
No full textIn the pursuit of developing touch sensors or tactile
sensing arrays, the emphasis has only been on the sensors. This
led to a large number of ‘bench top’ sensors, very few of which
have actually been used in robotic systems. And those that have
seen the actual use have almost invariably been used in static
contact point imaging rather than the active manipulation or
exploration. Perhaps the lack of the system approach rendered
many of them unusable. In this work, we present the design of a
tactile sensing system taking into account not only the parameters
to be sensed but also the physical and operational constraints of
robotic system
Piezoelectric polymer oxide semiconductor field effect transistor (POSFET) devices for touch sensing
No full textThis work presents the POSFET based touch
sensing devices and their experimental evaluation. POSFET
touch sensing devices presented here are primarily developed for
the robotic applications. The design of these devices is inspired
from human sense of touch. These devices are implemented by
spin coating thin (~2.5 μm) piezoelectric polymer (PVDF-TrFE)
film, directly on to the gate area of MOS transistor. The polymer
film is processed in situ. The POSFET device represents an
integral “sensotronic” unit comprising of transducer and the
transistor and are thus capable of ‘sensing and processing at
same site’. The POSFET touch sensing devices are tested in a
wide range (0.15-5N) of dynamic normal forces and at different
frequencies
Transistor-based Flexible Touch Sensors
No full textThis article introduces transistor-based tactile sensing devices. In particular, the piezoelectric oxide semiconductor field effect transistor (POSFET)-based tactile sensing devices are introduced. The-state-of-the-art integration of piezoelectric materials on silicon (Si)-based MOSFETs provides the opportunities of detecting dynamic forces. Further, by using chip thinning technologies, it is possible to achieve the devices in flexible form factors. In this regard, this article explains various routes explored for the development of flexible tactile sensing chips
Effect of ethical leadership and corporate social responsibility on firm performance: A systematic review
No full textAcademic and corporate interest in ethical leadership, corporate social responsibility (CSR), and firm performance has attracted a lot of attention in recent years. In fact, many research papers and journal special issues have been focused on these three domains. In this context, this paper conducts a systematic review on the concepts of ethical leadership and CSR and their impact on firm performance. 114 papers published over a period of 58 years (1958-2016) were selected and analyzed according to descriptive and content perspectives to propose a conceptual framework and define a future research agenda. In fact, the main results allow us to derive six main propositions representing possible areas of investigation to direct research on the topic. More in details, the body of literature highlights that financial factors are the main barriers affecting the adoption of CSR practices. On the contrary, internal and external environment was found to represent a critical success factor in the adoption of CSR practices. Finally, the results highlight that personal values have impact on ethical leadership that in turn has direct positive impact on CSR and direct and indirect impact on firm performance
Analysis of self-powered vibration-based energy scavenging system
No full textThis paper analyses a complete self-powered vibration based energy scavenging system. For the purpose of the analysis, the energy scavenging system (comprising of a SPICE model of Piezoelectric Bender Generator (PBG), an integrated semi-active bridge rectifier and a voltage regulator circuit) has been implemented in SPICE and presented in this paper. The semi-active bridge rectifier proposed in this paper uses Vertical Double-diffused MOS (VDMOS) transistors in place of standard diodes, to be suitable to withstand the high voltage values generated by PBGs. Using SPICE the analysis of the reciprocal interaction between PBG and scavenging system (in terms of stress, strain rate, mechanical and electrical powers at various loads and regulated voltages) is investigated. The simulation results of the semi-active bridge rectifier have shown an efficiency of the rectifier of about the 90 %. The simulation results of the whole system with optimized control circuits have shown how both the load and the regulated voltage can influence the behavior of stress and strain rate and vice versa. Comparisons of simulated stress and strain rate at various loads and regulated voltage values have shown an opposite behavior of the strain rate with respect to the stress. The simulation results of various powers - mechanical and electrical - from PBG to the load have shown the amount of mechanical power converted by the PBG into electrical that can be transferred to the load and that an optimal load exis
Identification and Validation of a Fractional Order Dynamic Model for a Piezoelectric Tactile Sensor
No full textThis paper presents the identification of a
piezoelectric tactile sensor which aims to give the sense of touch to
humanoid robots. The sensor has been characterized in frequency
domain and the low frequency behavior reveals a non-integer
behavior. A simple model based on the a priori knowledge of the
sensor and the observation of the frequency response has been
hypothesized and a least squares method has been applied to
identify the device. The impulse response has been calculated
using the Mittag-Leffler function and validation in time domain
has been performed. Simulation and experimental results are in
good agreement showing that the identified model, despite its
simplicity, is able to represent properly the tactile sensor
- …
