On Theoretical and Numerical Aspects of Bifurcations and Hysteresis Effects in Kinetic Energy Harvesters

The piezoelectric energy-harvesting system with double-well characteristics and hysteresis in the restoring force is studied. The proposed system consists of a bistable oscillator based on a cantilever beam structure. The elastic force potential is modified by magnets. The hysteresis is an additional effect of the composite beam considered in this system, and it effects the modal solution with specific mass distribution. Consequently, the modal response is a compromise between two overlapping, competing shapes. The simulation results show evolution in the single potential well solution, and bifurcations into double-well solutions with the hysteretic effect. The maximal Lyapunov exponent indicated the appearance of chaotic solutions. Inclusion of the shape branch overlap parameter reduces the distance between the external potential barriers and leads to a large-amplitude solution and simultaneously higher voltage output with smaller excitation force. The overlap parameter works in the other direction: the larger the overlap value, the smaller the voltage output. Presumably, the successful jump though the potential barrier is accompanied by an additional switch between the corresponding shapes.

Generation of long range and short range potentials

The general particle transfer (GPT) potential generates not only the Yukawa-type potential but also the 1⁄r^n-type potential in the hadron system, where the mass dependence of the transferred particle is clarified. The GPT potential from the atom-molecular system to the quark-gluon system was transversally studied, where the pico-meter physics could be highlighted. It was found that the long range three-body Efimov potential is connected with the short range three-body force potential.

Thumbnail Ver/Abrir 2021_Garcia_Perez_Jose_Diseno_implementacion-algoritmos-control-fuerza-robot-rehabilitacion-miembro-superior.pdf (5.367Mb) Use este enlace para citar http://hdl.handle.net/2183/28384 Atribución-NoComercial-CompartirIgual 4.0 Internacional https://creativecommons.org/licenses/by-nc-sa/4.0/deed.es Excepto si se señala otra cosa, la licencia del ítem se describe como Atribución-NoComercial-CompartirIgual 4.0 Internacional https://creativecommons.org/licenses/by-nc-sa/4.0/deed.es Colecciones XLII Jornadas de Automática [103] Metadatos Mostrar el registro completo del ítem Título Diseño e implementación de algoritmos de control de fuerza para un robot de rehabilitación de miembro superior Título(s) alternativo(s) Design and implementation of force control algorithms for an upper-limb rehabilitation robot Autor(es) García Pérez, José Vicente Blanco, A. Catalán Orts, José María Ezquerro, Santiago Álvarez-Pastor, Jesús Arnau-Papí, Jesús García Aracil, Nicolás Fecha 2021 Cita bibliográfica García-Pérez, J. V., Blanco, A., Catalán, J. M., Ezquerro, S., Álvarez-Pastor, J., Arnau-Papí, J., García-Aracil, N. Diseño e implementación de algoritmos de control de fuerza para un robot de rehabilitación de miembro superior. En XLII Jornadas de Automática: libro de actas. Castelló, 1-3 de septiembre de 2021 (pp.515-520). DOI capítulo: https://doi.org/10.17979/spudc.9788497498043.515 DOI libro: https://doi.org/10.17979/spudc.9788497498043 Resumen [Resumen] El envejecimiento de la población aumentará la incidencia de las enfermedades relacionadas con la edad, como los accidentes cerebrovasculares. La robótica ha demostrado ser efectiva en la aplicación de terapias de rehabilitación a personas que presenten una pérdida de movilidad asociada a estas patologías. Existen numerosos sistemas de control apropiados para la interacción entre robots y pacientes en este tipo de terapias. De entre ellos, en este artículo se propone el uso de campos de potencial de fuerza en un dispositivo robótico de rehabilitación de miembro superior para pacientes que hayan sufrido pérdida de movilidad debido a un accidente cerebrovascular. En la primera parte del artículo se expone la formulación de los campos de potencial y se define el dispositivo robótico en el que han sido implementados. Posteriormente, se plantea una experimentación con sujetos sanos para comprobar la validez de esta estrategia de control. Los resultados muestran una disminución del error en los movimientos de los sujetos y abren la puerta a pruebas posteriores con pacientes reales. [Abstract] The aging of population will increase the incidence of age-related diseases, such as strokes. Robotic devices have proven their effectiveness in rehabilitation therapies for people who have a lack of mobility due to these diseases. There are many different systems to control the robot-human interaction in this type of therapies. This article proposes the use of force potential fields in a robotic upper-limb rehabilitation device for stroke patients. In the first part of the article the formulation of the force potential fields is shown and the robotic device used for the study is presented. Finally, an experimentation with healthy subjects is proposed to check the validity of this control strategy. The results show a decrease in the error in the subjects’movements and open the door to further tests with real patients. Palabras clave Robótica de rehabilitación Sistemas de control Campos de potencial de fuerza Robotic rehabilitation Control systems Force potential field Versión del editor https://doi.org/10.17979/spudc.9788497498043.515 Derechos Atribución-NoComercial-CompartirIgual 4.0 Internacional https://creativecommons.org/licenses/by-nc-sa/4.0/deed.es ISBN 978-84-9749-804-3 Buscar en RUC Esta colección Listar Todo RUC Comunidades & Colecciones Por fecha de publicación Autores Títulos Materias Esta colección Por fecha de publicación Autores Títulos Materias Mi cuenta Acceder Registro Estadísticas Ver Estadísticas de uso

El envejecimiento de la población aumentará la incidencia de las enfermedades relacionadas con la edad, como los accidentes cerebrovasculares. La robótica ha demostrado ser efectiva en la aplicación de terapias de rehabilitación a personas que presenten una pérdida de movilidad asociada a estas patologías. Existen numerosos sistemas de control apropiados para la interacción entre robots y pacientes en este tipo de terapias. De entre ellos, en este artículo se propone el uso de campos de potencial de fuerza en un dispositivo robótico de rehabilitación de miembro superior para pacientes que hayan sufrido pérdida de movilidad debido a un accidente cerebrovascular. En la primera parte del artículo se expone la formulación de los campos de potencial y se define el dispositivo robótico en el que han sido implementados. Posteriormente, se plantea una experimentación con sujetos sanos para comprobar la validez de esta estrategia de control. Los resultados muestran una disminución del error en los movimientos de los sujetos y abren la puerta a pruebas posteriores con pacientes reales.

Healthcare and Sports from the Perspective of Qi, Fascia, and Taijiquan

The slow-motion practice of Taijiquan, operationally, cultivates the cognitive perception of fascia tension as it is being harnessed to discipline body motion to be in accord with Yin-Yang Balance. The ideal motion that results, bestows liveliness of change and harmonizes body momentum,the hallmarks of maneuverability and force potential for performance. The paper puts forth the proposition that the manifestation of Qi in Taijiquan is primarily the cognitive perception of fascial tension in the functional efficacy of bipedal balance for performance. Though the cultivated cognition may be subjective, the process of Qi nurturing is grounded on the reduction of the errors of imbalances, which carves a practice path to balance with tangible effects. The force that arises from body motion so imbued with Yin-Yang Balance, is of the phenomenon of internal strength or neijin—consummate, of the right force vector in spontaneous response and rooted in balance. Taijiquan practice nurtures Qi for both health wellbeing and neijin as the body's core strength, depending on the practice efforts put in.

The lifting force of an airplane wing when flying horizontally at high speeds. Explanation of the vortex trail.

In this paper, an explanation is given of the lift force of an airplane during horizontal flight. It is shown that during a flight, five vertical forces act on the airplane: gravity; pressure gradient with a minus sign; Archimedes force; potential force and the vortex force obtained from the action minimum. The first three forces were known before. The potential force was also known from the Bernoulli equation, but its effect on the airfoil from the air had not previously been taken into account. The vortex force obtained from the minimum action in the application to a continuous medium was not taken into account in aerodynamics. In horizontal flight the vortex force is directed upwards, it compensates for the gravity of the airplane at high speed commensurate with the speed of sound. The paper provides an explanation of the vortex trail behind the airplane, mentioned in the Millennium problem Navier-Stokes equation.

Temperature Variations in Multiple Air Layers before the Mw 6.2 2014 Ludian Earthquake, Yunnan, China

On 3 August 2014, an Mw 6.2 earthquake occurred in Ludian, Yunnan Province, China (27.245° N 103.427° E). This damaging earthquake caused approximately 400 fatalities, 1800 injuries, and the destruction of at least 12,000 houses. Using air temperature data of the National Center for Environmental Prediction (NCEP) and the tidal force fluctuant analysis (TFFA) method, we derive the temperature variations in multiple air layers between before and after the Ludian earthquake. In the spatial range of 30° × 30° (12°–42° N, 88°–118° E) of China, a thermal anomaly appeared only on or near the epicenter before earthquake, and air was heated from the land, then uplifted by a heat flux, and then cooled and dissipated upon rising. With the approaching earthquake, the duration and range of the thermal anomaly during each tidal cycle was found to increase, and the amplitude of the thermal anomaly varied with the tidal force potential: air temperature was found to rise during the negative phase of the tidal force potential, to reach peak at its trough, and to attenuate when the tidal force potential was rising again. A significance test supports the hypothesis that the thermal anomalies are physically related to Ludian earthquakes rather than being coincidences. Based on these results, we argue that the change of air temperature could reflect the stress changes modulated under the tidal force. Moreover, unlike the thermal infrared remote sensing data, the air temperature data provided by NCEP are not affected by clouds, so it has a clear advantage for monitoring the pre-earthquake temperature variation in cloudy areas.

Local regeneration and community wealth building–place making: co-operatives as agents of change

Purpose This paper aims to provide an introduction to how worker co-operatives and other organisations based on principles of the participatory economy have been adopted in a range of international contexts as a vehicle for transforming places with a strong aspiration to address location-specific social challenges. Design/methodology/approach Through a presentation of four narrative cases, the paper exemplifies international experiences of co-operative approaches to place-making. It critically reflects on the philosophical and strategic underpinnings of the projects implemented in Rochdale, Preston, Bologna, Rome and Cincinnati. Findings The practical experiences of a number of local projects of place-making involving co-operatives are conceptualised. The research has identified the importance of institutional, organisational and legal constraints for transformative cooperative-based place-making initiatives. It shows a strong relevance of the place’s historic legacy and communal governance for the choice of place-making approaches. Research limitations/implications Further investigation is needed to establish whether co-operatives have the same driving force potential in terms of local regeneration and community wealth building place-making in non-Western contexts and less developed locations. Practical implications The paper highlights cases that incorporate place-making practices involving the co-operative organisation and municipal participation and considers their transferability potential. Originality/value The paper advances an important conversation relevant to researchers, educators, co-operators, politicians and local officials on diverse contemporary approaches in towns and cities that seek to reshape and regenerate local socio-economic fabric by engaging tradition, principles and organisation models developed within the co-operative movement.

Tuning optical trapping of metal-dielectric hybrid nanoparticles under ultrafast pulsed excitation: A theoretical investigation

Crucial to effective optical trapping is the ability to precisely control the nature of force/potential to be attractive or repulsive. The nature of particle being trapped is as important as...