Investigations on the mechanical relevance of prominent vibrissa features for surface texture detection

The tactile hairs of animals are used as paradigm for artificial tactile sensors. In the case of mystacial vibrissae, the animals can determine the distance to an object, recognize the shape of the object and detect the surface texture of the object. The goal is to design an artificial tactile sensor inspired by the natural paradigm. In the present work, the vibrissa and the follicle-sinus-complex are modeled as a one-sided clamped beam within the limits of the non-linear Euler-Bernoulli beam theory. The theoretical background of the function principle and the effects of typical properties of the natural vibrissa, e.g., a tapered shape and a pre-curvature while operating in surface texture detection are analyzed. The beam-surface contact is described by Coulomb’s law of friction. When the beam is in touch with the surface, a quasi-static displacement of the support takes place. As a consequence of the displacement the support reactions are changing. The resulting support reactions are analyzed in parameter studies and beneficial levels of tapering and pre-curvature are identified

An artificial vibrissa-like sensor for detection of flows

In nature, there are several examples of sophisticated sensory systems to sense flows, e.g., the vibrissae of mammals. Seals can detect the flow of their prey, and rats are able to perceive the flow of surrounding air. The vibrissae are arranged around muzzle of an animal. A vibrissa consists of two major components: a shaft (infector) and a follicle–sinus complex (receptor), whereby the base of the shaft is supported by the follicle-sinus complex. The vibrissa shaft collects and transmits stimuli, e.g., flows, while the follicle-sinus complex transduces them for further processing. Beside detecting flows, the animals can also recognize the size of an object or determine the surface texture. Here, the combination of these functionalities in a single sensory system serves as paragon for artificial tactile sensors. The detection of flows becomes important regarding the measurement of flow characteristics, e.g., velocity, as well as the influence of the sensor during the scanning of objects. These aspects are closely related to each other, but, how can the characteristics of flow be represented by the signals at the base of a vibrissa shaft or by an artificial vibrissa-like sensor respectively? In this work, the structure of a natural vibrissa shaft is simplified to a slender, cylindrical/tapered elastic beam. The model is analyzed in simulation and experiment in order to identify the necessary observables to evaluate flows based on the quasi-static large deflection of the sensor shaft inside a steady, non-uniform, laminar, in-compressible flow

Validation of a Mechanical Model of the Active Scanning Process in the Rat Vibrissal System

The rat vibrissal system shows a sophisticated functionality in tactile discrimination, therefore it is analyzed in various works out of the perspective of neuroscience and bio-engineering. The present work focuses on the vibrissal system of rodents during tactile exploration in terms of mechanics. In this way, a mechanical model of the natural vibrissa is designed in order to determine the forces and moments at the base while the modeled vibrissa contacts a rough surface. The results of the mechanical simulation are compared to electrophysiological measurements of the afferent activity from vibrissal nerve in consequence of a contact between the vibrissa and real surface. This comparison gives information about the principal relation between mechanical and neuronal signals and furthermore about the electromechanical properties of the system.La sobresaliente capacidad de discriminación táctil del sistema vibrisal ha sido motivo de estudio en áreas de las neurociencias y bioingeniería. Este trabajo aborda los aspectos mecánicos de la exploración táctil efectuada a través del sistema vibrisal en roedores. Para ello se propone un modelo mecánico el cual permite predecir/determinar las fuerzas y momentos evocados en la base de la vibrisa durante el contacto activo con superficies rugosas. Asimismo, se realiza una validación electrofisiológica del modelo en base a registros de la actividad aferente del nervio vibrisal, evocados por el contacto activo. La estimación de estos parámetros mecánicos en el folículo vibrisal, no solo permite comprender los procesos que subyacen a la codificación neuronal, sino también aquellos relacionados a la transducción electromecánica del sistema.Fil: Scharff, Moritz. Pontificia Universidad Católica de Perú; Perú. Technische Universität Ilmenau; AlemaniaFil: Lucianna, Facundo Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Pizá, Alvaro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Albarracin, Ana Lia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; ArgentinaFil: Alencastre Miranda, Jorge H.. Pontificia Universidad Católica de Perú; PerúFil: Farfan, Fernando Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentin

Active Noise Control proposal design enhanced because of using sensors/actuators based on nanostructures

Big machines and motors, that under operating work produces high decibels of noise in wide range of work, these values are near 90 dB that is not healthy for humans. Normally, it is used passive mechanisms to attenuate noise such as big headphones. However that solution is not enough when noise has changes in frequency domain. Therefore, it is proposed in this work a solution by noise cancellation with Active Mechanisms; nevertheless, we designed a hybrid algorithm improved through predictive/adaptive concurrent algorithms strategies, with Active Noise Cancellation (ANC). By other side, based on nanostructures, it has been analyzed the effect in robustness and wide range of work by frequency domain in order to enhance noise cancellation

Magnetic Bearing Proposal Design for a General Unbalanced Rotor System enhanced because of using sensors/actuators based in nanostructures

Rotor systems need bearings in order to keep uniformity of rotational movement transmission. However, bearingsgenerate friction and energy losses due to heating transmisssion through the friction; for this reason, mechanicak bearings are replaced by magnetic bearings owing to avoid energy losing because of friction. We designed Active Magnetic Bearings (AMB) to transmit rotational movement from source of movement (motor) through the rotor to the movement receptor (such as a conveyor belt). Magnetic Bearings need accuracy during System Identification process and a sophisticated control algorithm to get an uniform rotation movement transmission. In this work also it was analyzed and proved by simulations that Active Magnetic Bearings composed with sensors /actuators based in nanostructures are faster and robust compared with AMB based in traditional sensors/actuators. It because, nanostructures receive and send signals better way tan traditional sensors/actuators, because of high oredered nanoarrays improve sensor/actuator properties

Magnetic Bearing Proposal Design for a General Unbalanced Rotor System enhanced because of using sensors/actuators based in nanostructures

Rotor systems need bearings in order to keep uniformity of rotational movement transmission. However, bearingsgenerate friction and energy losses due to heating transmisssion through the friction; for this reason, mechanicak bearings are replaced by magnetic bearings owing to avoid energy losing because of friction. We designed Active Magnetic Bearings (AMB) to transmit rotational movement from source of movement (motor) through the rotor to the movement receptor (such as a conveyor belt). Magnetic Bearings need accuracy during System Identification process and a sophisticated control algorithm to get an uniform rotation movement transmission. In this work also it was analyzed and proved by simulations that Active Magnetic Bearings composed with sensors /actuators based in nanostructures are faster and robust compared with AMB based in traditional sensors/actuators. It because, nanostructures receive and send signals better way tan traditional sensors/actuators, because of high oredered nanoarrays improve sensor/actuator properties

Active Noise Control proposal design enhanced because of using sensors/actuators based on nanostructures

Big machines and motors, that under operating work produces high decibels of noise in wide range of work, these values are near 90 dB that is not healthy for humans. Normally, it is used passive mechanisms to attenuate noise such as big headphones. However that solution is not enough when noise has changes in frequency domain. Therefore, it is proposed in this work a solution by noise cancellation with Active Mechanisms; nevertheless, we designed a hybrid algorithm improved through predictive/adaptive concurrent algorithms strategies, with Active Noise Cancellation (ANC). By other side, based on nanostructures, it has been analyzed the effect in robustness and wide range of work by frequency domain in order to enhance noise cancellation

Can the Inca site of Choqek'iraw be considered an agro-pastoral calendar?

International audience"Situated in the heart of the Vilcabamba cordillera in Peru, some 150 km northwest of Cuzco, the ancient Inca state capital, Choqek'iraw or Choquequirao (“the golden cradle” in Quechua), is one of the most beautiful achievements of Inca architecture, and one of the very few pre-Hispanic sites displaying large wall mosaics, the only one known from Inca times. This article will attempt to demonstrate that the figures represented on the walls convey cosmological significance and are laid out following textile principles. After describing the site and its geo-cultural setting, the mosaics' main characteristics will be examined in detail, in an attempt to grasp their meaning. Finally, the author suggests that some of the scenes depicted could have been inspired by pre-Columbian myths and could be linked to astronomical concepts." (source éditeur)"Ubicado en el corazón de la cordillera de Vilcabamba, a unos 150 kilómetros de Cuzco, la antigua capital del estado inca, Choqek'iraw o Choquequirao (la cuna del oro en quechua), es uno de los logros más hermosos de la arquitectura Inca y el único sitio de época inca, con un gran mosaico mural. En este trabajo se intentará demostrar que las figuras representadas en las paredes podrían transmitir significado cosmológico y se distribuyen siguiendo principios textiles. Asimismo, después de hacer una breve descripción del sitio, ubicándolo en sus contextos geográfico y cultural, se analizarán las principales decoraciones que allí se encuentran para tratar de entenderlas. Los temas representados podrían referirse a antiguos mitos andinos y concepciones de orden astronómicos." (source éditeur