Sma control for bio-mimetic fish locomotion

In this paper, we describe our current work on bio-inspired locomotion systems using smart materials. The aim of this work is to investigate alternative actuation mechanisms based on smart materials, exploring the possibility of building motor-less and gear-less robots. A swimming underwater robot is being developed whose movements are generated using such materials, concretely Shape Memory Alloys. This paper focuses on the actuators control in order to generate the desired motion pattern

SMA-Based Muscle-Like Actuation in Biologically Inspired Robots: A State of the Art Review

New actuation technology in functional or "smart" materials has opened new horizons in robotics actuation systems. Materials such as piezo-electric fiber composites, electro-active polymers and shape memory alloys (SMA) are being investigated as promising alternatives to standard servomotor technology [52]. This paper focuses on the use of SMAs for building muscle-like actuators. SMAs are extremely cheap, easily available commercially and have the advantage of working at low voltages. The use of SMA provides a very interesting alternative to the mechanisms used by conventional actuators. SMAs allow to drastically reduce the size, weight and complexity of robotic systems. In fact, their large force-weight ratio, large life cycles, negligible volume, sensing capability and noise-free operation make possible the use of this technology for building a new class of actuation devices. Nonetheless, high power consumption and low bandwidth limit this technology for certain kind of applications. This presents a challenge that must be addressed from both materials and control perspectives in order to overcome these drawbacks. Here, the latter is tackled. It has been demonstrated that suitable control strategies and proper mechanical arrangements can dramatically improve on SMA performance, mostly in terms of actuation speed and limit cycles

El derecho, periódico de ideas: Historia y patrimonio gráfico

El artículo expone la evolución gráfica e histórica del periódico “El Derecho”; la investigación se enmarcó bajo el paradigma cualitativo, desde el enfoque histórico hermenéutico y método etnográfico. A su vez, contempló los siguientes aspectos: político, social, cultural y gráfico, en los cuales se ponen en evidencia las realidades  el departamento de Nariño, así como la riqueza visual existente en sus páginas. En éste se destaca la importancia del periódico como medio de denuncia, de construcción y de contraposición de ideas, que marcó un hito en la renovación de la región nariñense. Por su parte, el aspecto gráfico desde lo editorial lo constituyó como “vehículo de pensamiento”, capaz de mantener y atender las necesidades de la sociedad

“El Derecho”, a newspaper of ideas: history and graphic patrimony

El artículo expone la evolución gráfica e histórica del periódico “El Derecho”; la investigación se enmarcó bajo el paradigma cualitativo, desde el enfoque histórico hermenéutico y método etnográfico. A su vez, contempló los siguientes aspectos: político, social, cultural y gráfico, en los cuales se ponen en evidencia las realidades  el departamento de Nariño, así como la riqueza visual existente en sus páginas. En éste se destaca la importancia del periódico como medio de denuncia, de construcción y de contraposición de ideas, que marcó un hito en la renovación de la región nariñense. Por su parte, el aspecto gráfico desde lo editorial lo constituyó como “vehículo de pensamiento”, capaz de mantener y atender las necesidades de la sociedad.Abstract The article presents the graphic and historical evolution of the newspaper “El Derecho”; the investigation was made under the qualitative paradigm, from the historical hermeneutic approach and the ethnographic method. At the same time, it included the following aspects: political, social, cultural and graphic, in which the realities of the department of Nariño, as well as the visual richness existing in its pages are evidenced. It highlights the importance of the newspaper as a means of complaint, of construction and contrast of of ideas, which became a milestone in the renewal of the Nariño region. Meanwhile the graphic aspect from the publisher was constituted as a “vehicle of thought”, able to maintain and meet the needs of society

Celdas solares orgánicas, una perspectiva hacia el futuro

La búsqueda de fuentes de energía alternativas a los combustibles fósiles ha permitido el desarrollo y uso de diferentes tecnologías basadas en el uso de la energía solar. Las celdas solares basadas en compuestos organicos ofrecen grandes ventajas en aspectos económicos, ambientales y tecnológicos y es por eso que la evolución que ha tenido desde sus comienzos ha permitido su paso hacia la producción a mediana escala por lo que sus perspectivas de crecimiento son muy alentadoras

Free vibration analysis of a robotic fish based on a continuous and non-uniform flexible backbone with distributed masses

This paper presents a differential quadrature element method for free transverse vibration of a robotic-fish based on a continuous and non-uniform flexible backbone with distributed masses (represented by ribs) based in the theory of a Timoshenko cantilever beam. The effects of the masses (Number, Magnitud and position) on the value of natural frequencies are investigated. Governing equations, compatibility and boundary conditions are formulated according to the Differential Quadrature rules. The compatibility conditions at the position of each distributed mass are assumed as the continuity in the vertical displacement, rotation and bending moment and discontinuity in the transverse force due to acceleration of the distributed mass. The convergence, efficiency and accuracy are compared to other analytical solutions proposed in the literature. Moreover, the proposed method has been validate against the physical prototype of a flexible fish backbone. The main advantages of this method, compared to the exact solutions available in the literature are twofold: first, smaller time-cost and second, it allows analysing the free vibration in beams whose section is an arbitrary function, which is normally difficult or even impossible with analytical other methods

Promoting higher order thinking skills in biology: evaluation of a newly developed course using Bloom’s taxonomy.

We have recently designed and implemented a unique, large (1800 students/year) first year biological concepts of health course (BIOL*1080) aimed at promoting higher order thinking skills and attributes. Our course served as one of three courses that replaced two more traditional biology courses (BIOL*1030 and BIOL*1040) and incorporates seminar, lab and interdisciplinary assignments in an attempt to foster skills in areas such as oral and written communication, critical thinking, and independent learning. To determine if we were successful in designing a course centered on the teaching and assessment of higher order thinking skills, we ranked the course evaluative materials based on Bloom’s taxonomy (Zheng, A.Y., Science 319:414,2008). Bloom’s taxonomy is a hierarchical categorization of knowledge and thinking skills comprised of 6 levels (from lowest to highest): knowledge - 1, comprehension – 2, application – 3, analysis – 4, synthesis – 5, and evaluation – 6. Briefly, each exam question and assignment was scored by a team of 6 individuals with varying degrees of familiarity with the course. Scores per test/assignment were averaged and a weighted average was calculated for the entire course, with a higher weighted average representing assessment of a higher order of thinking. The average bloom level for our course was 3.28±0.15 which was significantly higher than one of the more traditional biology courses (BIOL*1030 – 1.93±0.08 ) but not the second course (BIOL*1040 – 2.95±0.17). The blooming exercise provided a useful metric to assess the level of higher order thinking required for newly developed courses and allowed for comparisons between courses to be objective

Aerial Remote Sensing in Agriculture: A Practical Approach to Area Coverage and Path Planning for Fleets of Mini Aerial Robots

In this paper, a system that allows applying precision agriculture techniques is described. The application is based on the deployment of a team of unmanned aerial vehicles that are able to take georeferenced pictures in order to create a full map by applying mosaicking procedures for postprocessing. The main contribution of this work is practical experimentation with an integrated tool. Contributions in different fields are also reported. Among them is a new one-phase automatic task partitioning manager, which is based on negotiation among the aerial vehicles, considering their state and capabilities. Once the individual tasks are assigned, an optimal path planning algorithm is in charge of determining the best path for each vehicle to follow. Also, a robust flight control based on the use of a control law that improves the maneuverability of the quadrotors has been designed. A set of field tests was performed in order to analyze all the capabilities of the system, from task negotiations to final performance. These experiments also allowed testing control robustness under different weather conditions

Comportamiento físico mecánico de la tapia por pandeo y conexión de esquina. Caso Teatro Imperial de Pasto.

Introducción: La tapia, es un muro ancestral fabricado artesanalmente en tierra apisonada, con la que se construyeron edificaciones patrimoniales en la ciudad de Pasto, (zona de amenaza sísmica alta), entre ellas el teatro Imperial el cual es considerado como un patrimonio invaluable (1922) conocido como el “Decano de los Teatros del Sur” [1] declarado como de uno de los bienes inmuebles de interés cultural de la nación y protegido por las leyes que regula el Ministerio de Cultura. Metodología: La investigación se desarrolla a partir de evaluación patológica causada por antecedentes sísmicos en el comportamiento estructural por pandeo y conexión de esquina de las edificaciones en tierra, para ello se evalúa el comportamiento físico mecánico de la tapia a partir de procesos convencionales como el módulo de rotura, evaluación de resistencia admisible a la compresión de la tapia, como una respuesta al pandeo y la valoración dinámica para caracterizar la razón de amortiguamiento y frecuencia de resonancia con base en la evaluación de vibraciones libres. Como metodología la investigación propone un nuevo ensayo a partir de una probeta que permita establecer los esfuerzos que se desarrollan en la conexión de esquina y el refuerzo que contrarreste dicha vulnerabilidad. Resultados: El muro en tapia se caracteriza como un sólido deformable altamente frágil, sujeto a pandeo y fisuramiento, valorado como un medio continuo, con base en el cálculo de elasticidad (72 Mpa), esfuerzo cortante (28 Mpa), relación de deformación vertical y horizontal (0,33) y resistencia a la compresión (0,59 Mpa), caracterizado como un suelo consolidado de consistencia media dura, con un módulo de rotura (0,14Mpa). Conclusiones: El desprendimiento de las esquinas de los muros en tapia se presenta por la alta concentración de esfuerzos, los cuales se resuelven mediante la instalación de conectores o clavos. El ensayo de vibraciones libres permite obtener los modos de vibración longitudinal, transversal y torsional para determinar la capacidad de amortiguamiento de la acción dinámica causada por un sismo. El módulo de rotura permite interpretar la capacidad de respuesta frente a la flexión y pandeo que se causa en un muro en tapia.Introduction− The Tapia, is an ancestral wall material made by hand in packed earth, which heritage builtdings were built with in Pasto City, (area of high seismic threat) includ-ing the Imperial Theater (1922), known as the “Dean of the Southern Theaters” [1] declared it as one of the real estate of cultural interest of the nation, protected by the Ministry of culture’s laws.Methodology−The investigation is developed from pathologi-cal evaluation caused by seismic antecedents in the structural behavior by buckling and corner connection of buildings on land, for this the physical mechanical behavior of the wall is evaluated from conventional processes such as the breaking module , evaluation of admissible resistance to the compression of the wall, as a response to buckling and dynamic assessment to characterize the damping ratio and resonance frequency based on the evaluation of free vibrations. As a methodology, the research proposes a new test from a piece that allows es-tablishing the efforts that are developed in the corner connec-tion and the reinforcement that counteracts this vulnerability.Results−The Tapia wall is characterized as a deformable solid highly fragile, subject to buckling and cracking which was assessed as a continuous medium based on the calcula-tion of elasticity (72 Mpa), shear (28Mpa), ratio of vertical and horizontal deformation (0.33) and compressive strength (0.59 Mpa) characterized as a consolidated soil of medium hard con-sistency, with a modulus of rupture (0.14Mpa). Conclusions−It is possible to improve the behavior of build-ings on land subjected to bending stress, applying a reinforced cloth with cement floor and reinforcing mesh. The detachment of the corners of the walls is presented by the high concentra-tion of efforts, which are resolved by the installation of con-nectors or nails. The free vibration test allows to obtain the longitudinal, transversal and torsional vibration modes to determine the damping capacity of the dynamic action caused by an earthquake. The breaking module allows to interpret the capacity of response in front of the bending and buckling that is caused in a wall in the wall