Examinando por Materia "Dynamics"
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Ítem Analytical method for the kinetostatic analysis of the second-class RRR assur group allowing for friction in the kinematic pairs(Springer Berlin Heidelberg, 2010-07-01) Durango, S.; Calle, G.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThe calculation of forces in the kinematic pairs of mechanisms by inverse dynamics is usually performed without friction considerations. In practice, when examination of articulated mechanisms takes into account friction, the solution of the inverse dynamics results in a complex procedure. If a modular approach for the inverse dynamics is used, then exact solutions are available, but not necessarily are practical. For example, the analytical solution for a second-class first-type Assur group is a 16th degree equation. Previous researches proposed an approximated but practical (graphical) method to calculate the forces on the kinematic pairs taking into account the friction forces. In this article, an analytical interpretation of the Artobolevski approximated method is developed for the second-class Assur group with three rotational pairs. The final results for the reactions calculated with the implemented method present a good approximation with respect to the graphical solution. Future work should consider friction forces not only in second-class groups with rotational joints, but also in second-class groups with prismatic joints and high-class Assur groups. Copyright © 2010 by ABCM.Ítem La cadena de valor de la industria de Cannabis en Colombia : análisis estratégico(Universidad EAFIT, 2021) Maldonado Castañeda, Jairo Alberto; Giraldo Hernández, Gina MaríaCannabis around the world has developed a legal market as a supplier of raw materials for the pharmaceutical industry with a market size of USD 12 billion in 2018 and it is expected that by 2025 it will reach a size of USD 166 billion, positioning itself as a disruptive industry, since technological and scientific advances have made it possible to exploit a large number of benefits of this plant, making it an interesting input for the cosmetics industry, medicines, personal care, food packaging, beverages, pet care, veterinary medicines, gardening , clothing, paper, and even luxury goods. Given this potential, Colombia has started the development of its Cannabis industry and due to certain comparative advantages such as lower production costs, a good productive infrastructure and availability of qualified and unqualified workers, the country is projected as one of the with greater potential for the production and transformation of these products. However, it presents challenges and threats that you must analyzing to not lose the window of opportunity that it presented. This paper proposes to analyze the value chain of the cannabis industry in Colombia, to characterize and analyze the different actors that make it up and identify challenges and opportunities from a strategic approach. For this, an analysis of the macroeconomic environment was carried out through the PESTLE analysis supported by the AHP (Analytic Hierarchy Process) and ANP (Analytic Network Process) techniques. Subsequently, the analysis of the industry was carried out under the model of the Porte´s five forces, where the structure of the industry and which force dominates it was determined. Subsequently, the strategic dimensions were identified and a strategic groups map was made, where it was determined which are present in the industry and theses was analyzed through the Value Chain Analysis (VCA) model developed by Porter. This work is expected to provide a strategic analysis for decision makers to design their business strategies and identify challenges and opportunities.Ítem Dynamics Between Quantities and Prices in Argentine Dairy Chain: A Structural Cointegration Analysis(Universidad EAFIT, 2019-11-18) Vicentin Masaro, Jimena; Universidad del LitoralÍtem Measuring displacement within a transfemoral socket using marker-based optical tracking system: Static tests(AMER SOC MECHANICAL ENGINEERS, 2017-01-01) Salazar-Salgado S.; Rendón-Vélez E.In lower limb amputees, the comfort and fit of the prosthesis determine whether the user wears or not the prosthesis, fact on which a successful rehabilitation depends. The prosthetic fit is highly related with the relative motion between the socket and the residual limb (i.e., displacement). Displacement has been measured in static and dynamic position and between several surfaces such as skin-socket, liner-socket, bone-socket using various instruments. Marker-based optical tracking system is one of the most recent instruments used for measuring displacement between the socket and the residual limb that solves many of the constraints faced by other measurement instruments. Two options have been reported on the literature for using this instrument: transparent test socket with 2D marker and definite socket with cavities and 3D marker, both facing different limitations. The objective of this study is to evaluate these two options using Marker-based optical tracking system in order to give recommendations and contribute to the use of this method on future research. Two sockets were used for the study: a transparent socket and a definite socket with and without cavities. Six trials were performed using both sockets with three types of markers located inside the socket: 2D circular, 3D hemisphere and 3D sphere. VICON motion capture system was used to detect the visibility of the markers at knee flexion angles (0° to 30°). The results showed that all markers were visible from 15° to 30° knee flexion in all trials. The 2D marker presented difficulty of detection on knee angles from 0° to 10°, especially on the final socket without cavities. 3D hemisphere marker was seen almost all along the knee angles. 3D-sphere marker was visible in all positions, but the relatively large size of these markers may not be adequate to measure displacement. Using the definite socket with the 2D circular and 3D hemisphere markers could be a good option to measure displacement between the residual limb and socket. Using this socket will be closer to reality than doing it on the transparent one. Additionally, the size of the 3D-hemisphere is relatively small, it may not drastically change the behavior between surfaces and as it is a 3D marker it can be better seen by the cameras Further tests should be done with patients walking all along the path in order to assess if the markers visibility is the same on static and dynamic trials. © Copyright 2017 ASME.Ítem Modeling and control of nonlinear systems using an Adaptive LAMDA approach(Elsevier BV, 2020-01-01) Morales L.; Aguilar J.; Rosales A.; Chávez D.; Leica P.; Morales L.; Aguilar J.; Rosales A.; Chávez D.; Leica P.; Universidad EAFIT. Departamento de Ingeniería de Sistemas; I+D+I en Tecnologías de la Información y las ComunicacionesThis paper presents a soft computing technique for modeling and control of nonlinear systems using the online learning criteria. In order to obtain an accurate modeling, and therefore a controller with good performance, a method based on the fundamentals of the artificial intelligence algorithm, called LAMDA (Learning Algorithm for Multivariate Data Analysis), is proposed, with a modification of its structure and learning method that allows the creation of an adaptive approach. The novelty of this proposal is that for the first time LAMDA is used for fuzzy modeling and control of complex systems, which is a great advantage if the mathematical model is not available, partially known, or variable. The adaptive LAMDA consists of a training stage to establish initial parameters for the controller, and the application stage in which the control strategy is computed and updated using an online learning that evaluates the closed-loop system. We validate the method in several control tasks: (1) Regulation of mixing tank with variable dead-time (slow variable dynamics), (2) Regulation of a Heating, Ventilation and Air-Conditioning (HVAC) system (multivariable slow nonlinear dynamics), and (3) trajectory tracking of a mobile robot (multivariable fast nonlinear dynamics). The results of these experiments are analyzed and compared with other soft computing control techniques, demonstrating that the proposed method is able to perform an accurate control through the proposed learning technique. © 2020 Elsevier B.V.Ítem Modeling the sediment dynamics in the gulf of Urabá colombian Caribbean sea(Elsevier Ltd, 2018-01-01) Escobar C.A.; Velásquez-Montoya L.; Universidad EAFIT. Departamento de Geología; Ciencias del MarThe potential of the gulf of Urabá to hold a multi-purpose port motivated a sediment dynamics study to describe the seasonal sediment concentration patterns in this tropical region. Challenges addressed in this study include a complex three-dimensional flow pattern in a tropical estuary and the lack of in-situ measurements. To overcome such challenges, this study completed: (i) Measurements of suspended sediment concentrations during two climatic seasons and an extreme event (2010–2011); (ii) Definition of boundary conditions from global databases; (iii) Qualitative analysis of sediment concentrations from satellite imagery; and (iv) integration of the previously mentioned steps to build a process-based 3D sediment transport model. Seasonal patterns of suspended sediment concentrations were identified and corroborated by the agreement between model results, satellite imagery and field measurements. During the calm rainy season, the Atrato River turbid plume extends northward and dominates the sediment dynamics in the gulf. On the other hand, during the dry season and extreme events, bed transport is enhanced and the river's plume and the littoral drift shift southwards. © 2017 Elsevier Ltd