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Upper limb assessment in tetraplegia: clinical, functional and kinematic correlations

CACHO, Enio Walker Azevedo; OLIVEIRA, Roberta de; ORTOLAN, Rodrigo L.; VAROTO, Renato; CLIQUET JR., Alberto
Fonte: LIPPINCOTT WILLIAMS & WILKINS Publicador: LIPPINCOTT WILLIAMS & WILKINS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.78%
The aim of this study was to correlate clinical and functional evaluations with kinematic variables of upper limp reach-to-grasp movement in patients with tetraplegia. Twenty chronic patients were selected to perform reach-to-grasp kinematic assessment using a target placed at a distance equal to the arm`s length. Kinematic variables (hand peak velocity, movement time, percent time-to-maximal velocity, index of curvature, number of peaks, and joint range of motion) were correlated to clinical (Standard Neurological Classification of Spinal Cord Injury-American Spinal Injury Association) and functional [Functional Independence Measure (FIM) and Spinal Cord Independence Measure II (SCIM II)) evaluation scores. Twenty control participants were also selected to obtain normal reference parameters. There was a positive correlation between total motor index and FIM (r=0.6089; P=0.0044) and SCIM II (r=0.5229; P=0.018). Both functional scores showed positive correlation with each other (r=0.8283; P<0.0001). A correlation was also observed between the right and left motor indices, the motor AM, and the SCIM II in most of the reach-to-grasp kinematic variables studied (hand peak velocity, movement time, index of curvature, and number of peaks). In contrast...

Análise cinemática da largada do bobsled; Kinematic analysis of bobsled start

Lopes, Alexandre Dias
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 05/10/2006 PT
Relevância na Pesquisa
36.69%
O bobsled é um esporte desenvolvido para prática de inverno e tem como objetivo principal, percorrer uma pista de gelo inclinada de aproximadamente 1500m no menor tempo possível. A atividade é iniciada com o trenó parado, sem movimento. Existem duas modalidades, o bobsled para quatro pessoas e bobsled para duas pessoas. O movimento inicial do bobsled é conhecido como o momento de propulsão do trenó ou da largada, já teve sua importância demonstrada para a obtenção de um bom desempenho final em estudos anteriores, é executado na modalidade de dois atletas pelo atleta piloto e pelo atleta breakman. Os objetivos deste trabalho se preocuparam em investigar a existência de um padrão cinemático adotado pelos atletas piloto e atletas breakman durante o momento de propulsão do trenó das 15 melhores equipes participantes do campeonato, assim como a existência da relação entre o tempo de largada e o tempo final da prova e a variação do desempenho obtido entre todas as equipes participantes. As imagens utilizadas neste trabalho foram adquiridas durante o XIV Campeonato Mundial de Bobsled masculino na modalidade de dois atletas, realizado na cidade de Koonigssee (Alemanha) em 2004. Para se investigar o padrão cinemático foram utilizadas variáveis relacionadas a angulação do ombro...

Comparação entre julgamento tradicional e avaliação cinemática do salto de cavalos da raça Brasileiro de Hipismo; Comparison between traditional judgement and jumping kinematic evaluation of Brazilian Sport horses

Miyashiro, Patricia
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 14/06/2012 PT
Relevância na Pesquisa
36.61%
O objetivo do presente trabalho foi descrever as características cinemáticas do salto de cavalos da raça Brasileiro de Hipismo, avaliar o julgamento realizado pelos juízes durante uma competição de salto em liberdade e comparar essas avaliações. Foram utilizados 13 equinos da raça Brasileiro de Hipismo, machos não castrados (40,15±4,24 meses, 491,1±40,89 kg). Os animais foram filmados saltando um obstáculo oxer durante uma competição de saltos em liberdade. Trajetórias do centro de massa corporal (CM) foram calculadas através da posição de pontos anatômicos que foram rastreados manualmente desde a decolagem até o pouso. Dessa trajetória, variáveis biomecânicas foram calculadas: velocidade vertical e horizontal, ângulos da velocidade e do deslocamento do CM na decolagem, altura máxima, deslocamento vertical e horizontal do CM, altura e fração de encurtamento dos membros sobre o obstáculo. Um polinômio de segunda ordem foi calculado através da trajetória do CM para obter três constantes com base na equação resultante. Os cavalos foram avaliados por três juízes: medidas zoométricas, funcionalidade, morfologia, salto, genealogia e modelo de garanhão. As notas de julgamento são consistentes entre si...

Planejamento cinemático-dinâmico de movimento com desvio local de obstáculos utilizando malhas de estados; Kinematic-dynamic motion planning with local deviation of obstacles using lattice states

Magalhães, André Chaves
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 06/06/2013 PT
Relevância na Pesquisa
36.74%
Planejamento de movimento tem o propósito de determinar quais movimentos o robô deve realizar para que alcance posições ou configurações desejadas no ambiente sem que ocorram colisões com obstáculos. É comum na robótica móvel simplificar o planejamento de movimento representando o robô pelas coordenadas do seu centro e desconsiderando qualquer restrição cinemática e dinâmica de movimento. Entretanto, a maioria dos robôs móveis possuem restrições cinemáticas não-holonômicas, e para algumas tarefas e robôs, é importante considerar tais restrições juntamente com o modelo dinâmico do robô na tarefa de planejamento. Assim é possível determinar um caminho que possa ser de fato seguido pelo robô. Nesse trabalho é proposto um método de planejamento cinemático-dinâmico que permite planejar trajetórias para robôs móveis usando malhas de estados. Essa abordagem considera a cinemática e a dinâmica do robô para gerar trajetórias possíveis de serem executadas e livre de colisões com obstáculos. Quando obstáculos não representados no mapa são detectados pelos sensores do robô, uma nova trajetória é gerada para desviar desses obstáculos. O planejamento de movimento utilizando malhas de estados foi associado a um algoritmo de desvio de obstáculos baseado no método da janela dinâmica (DWA). Esse método é responsável pelo controle de seguimento de trajetória...

Comparação das variáveis cinemáticas, eletromiográficas e do conusmo de oxigênio da corrida no triathlon com uma corrida prolongada e uma corrida isolada; Comparison of kinematic and electromyographic variables and oxygen uptake of the triathlon running with a prolonged run and an isolated run

Fraga, Carina Helena Wasem
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
36.69%
A corrida representa um importante segmento do triathlon, sendo precedida pela prova de ciclismo. A compreensão dos efeitos do ciclismo sobre o desempenho da corrida, portanto, se torna indispensável para a otimização dos resultados finais de uma prova. O objetivo desse estudo foi comparar as variáveis cinemáticas, eletromiográficas e o consumo de oxigênio da corrida no triathlon com àquelas de uma corrida isolada e de uma corrida prolongada. As seguintes variáveis foram avaliadas no presente estudo: (1) freqüência e amplitude de passada; (2) o valor RMS (root mean square) médio do sinal EMG dos músculos bíceps femoral, reto femoral, vasto lateral, gastrocnêmio medial e tibial anterior; e, (3) o VO2. Participaram desse estudo nove triatletas do sexo masculino. O protocolo de avaliação foi realizado em três etapas: (1) teste para obtenção do VO2 máx, realizado em esteira ergométrica; (2) teste que envolveu a sucessão ciclismo-corrida da prova de triathlon (CT), com 40 km de ciclismo, seguidos de10 km de corrida – em um contexto de prova simulada; e (3) teste de corrida prolongada (CP), em que o atleta correu o tempo correspondente aos 40 km de ciclismo somado a 10 km de corrida. Os primeiros 10 km dessa corrida prolongada constituíram a corrida isolada (CI). Os dados cinemáticos...

Kinematic analysis of Labrador Retrievers and Rottweilers trotting on a treadmill

Agostinho, F. S.; Rahal, S. C.; Miqueleto, N. S. M. L.; Verdugo, M. R.; Inamassu, L. R.; El-Warrak, A. O.
Fonte: Schattauer Gmbh-verlag Medizin Naturwissenschaften Publicador: Schattauer Gmbh-verlag Medizin Naturwissenschaften
Tipo: Artigo de Revista Científica Formato: 185-191
ENG
Relevância na Pesquisa
36.74%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Objectives: The purpose of the study was to evaluate kinematic patterns in clinically normal Labrador and Rottweiler dogs trotting on a treadmill at a constant velocity.Methods: Ten Labrador Retrievers aged from 2.2 to 5.1 years, and 10 Rottweilers aged from two to 5.9 years were used. A three-dimensional capture system was used to perform analysis of joint kinematics. Kinematic data were collected by use of a triple-camera system. The kinematic study was performed first on the right side of the dog, and then on the left side. Data were analysed by use of a motion-analysis program. Flexion and extension joint angles, angular velocity and angular acceleration were determined for the shoulder, elbow, carpal, hip, stifle, and tarsal joints.Results: Within each group, the differences between the right and left limbs in all variables were not significant. Significant differences occurred between Labradors and Rottweilers in the following categories: angular displacement and minimum angular acceleration of the stifle (Rottweiler >Labrador); angular displacement and maximum angular velocity of the tarsus (Rottweiler >Labrador); minimum angular velocity of the shoulder (Labrador >Rottweiler); angular displacement...

Spectral analysis and low-frequency multipath mitigation for kinematic applications

Souza, E. M. de; Monico, J. F. G.; Polezel, W. G. C.; Pagamisse, A.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Conferência ou Objeto de Conferência Formato: 413-417
ENG
Relevância na Pesquisa
36.61%
Low-frequency multipath is still one of the major challenges for high precision GPS relative positioning. In kinematic applications, mainly, due to geometry changes, the low-frequency multipath is difficult to be removed or modeled. Spectral analysis has a powerful technique to analyze this kind of non-stationary signals: the wavelet transform. However, some processes and specific ways of processing are necessary to work together in order to detect and efficiently mitigate low-frequency multipath. In this paper, these processes are discussed. Some experiments were carried out in a kinematic mode with a controlled and known vehicle movement. The data were collected in the presence of a reflector surface placed close to the vehicle to cause, mainly, low-frequency multipath. From theanalyses realized, the results in terms of double difference residuals and statistical tests showed that the proposed methodology is very efficient to detect and mitigate low-frequency multipath effects. © 2008 IEEE.

Avaliação da extremidade superior de tetraplégicos : correlações clínicas, funcionais e cinemáticas; Upper limb assessment in tetraplegia : clinical, functional and kinematic correlations

Enio Walker Azevedo Cacho
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 24/08/2010 PT
Relevância na Pesquisa
36.69%
Vários são os instrumentos de avaliação dedicados aos tetraplégicos. A compreensão de suas relações é de fundamental importância para o desenvolvimento e elaboração de abordagens terapêuticas voltadas à reabilitação da extremidade superior desses indivíduos. Assim, o objetivo deste estudo foi analisar as correlações entre as avaliações clínicas, funcionais e cinemáticas da extremidade superior durante os movimentos de alcance-preensão em tetraplégicos. Vinte tetraplégicos crônicos e vinte participantes controles foram selecionados para o estudo. Os instrumentos utilizados para a avaliação foram: o padrão de classificação da Associação Americana de Lesão Medular – ASIA, a Medida de Independência Funcional – MIF, a Mensuração de Independência da Medula espinhal – SCIM II, e a avaliação cinemática do movimento de alcance-preensão. Foram utilizadas as seguintes variáveis cinemáticas: deslocamento anterior do tronco e protração do ombro, amplitude articular do ombro, cotovelo e punho nos planos sagital e horizontal, índice de curvatura, pico de velocidade máxima, razão do pico de velocidade máxima, tempo de movimento e número de picos. O deslocamento anterior do tronco, protração do ombro e as amplitudes articulares do ombro e cotovelo não apresentaram diferenças significativas entre os tetraplégicos e os controles. Apenas a amplitude de flexoextensão do punho foi significativamente maior em tetraplégicos. Os movimentos dos tetraplégicos foram mais lentos...

Kinematic control of constrained robotic systems

Freitas,Gustavo M.; Leite,Antonio C.; Lizarralde,Fernando
Fonte: Sociedade Brasileira de Automática Publicador: Sociedade Brasileira de Automática
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2011 EN
Relevância na Pesquisa
36.69%
This paper addresses the posture control problem for robotic systems subject to kinematic constraints. The key idea is to consider the kinematic constraints of the mechanisms from their structure equations, instead of explicitly using the constraint equations. A case study for parallel robots and cooperating redundant robots is discussed based on the following concepts: forward kinematics, differential kinematics, singularities and kinematic control. Simulations results, obtained with a Four-Bar linkage mechanism, a planar Gough-Stewart platform and two cooperating robots, illustrate the applicability and versatility of the proposed methodology.

Virtual kinematic chains to solve the underwater vehicle-manipulator systems redundancy

Santos,Carlos H. F. dos; Guenther,Raul; Martins,Daniel; De Pieri,Edson R.
Fonte: Associação Brasileira de Engenharia e Ciências Mecânicas - ABCM Publicador: Associação Brasileira de Engenharia e Ciências Mecânicas - ABCM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2006 EN
Relevância na Pesquisa
36.74%
This paper addresses the kinematics of the Underwater Vehicle-Manipulator Systems (UVMSs). Due the adittional degrees of freedom (dofs) provided by the vehicle, such systems are kinematically redundant, i.e. they possess more dofs than those required to execute a given task, and need to be solved using some redundancy technique. We present an approach based on introducing kinematic constraints. The approach uses the screw representation of movement and is based on the so-called Davies method used to solve the kinematics of closed kinematic chains. We describe the vehicle-manipulator system as an open-loop chain and present a virtual kinematic chain concept that allows closing this open chain. Applying the Davies method to this resulting closed chain, the UVMS direct kinematic is solved. The inverse kinematics is obtained using the same approach, by introducing extra constraints derived from energy savings requirements. The proposed approach is compared to another redundancy resolution method to illustrate the ability of the proposed strategy.

Insights into Contractional Fault-Related Folding Processes Based on Mechanical, Kinematic, and Empirical Studies

Hughes, Amanda
Fonte: Harvard University Publicador: Harvard University
Tipo: Thesis or Dissertation
EN_US
Relevância na Pesquisa
36.61%
This dissertation investigates contractional fault-related folding, an important mechanism of deformation in the brittle crust, using a range of kinematic and mechanical models and data from natural structures. Fault-related folds are found in a wide range of tectonic settings, including mountain belts and accretionary prisms. There are several different classes of fault-related folds, including fault-bend, fault-propagation, shear-fault-bend, and detachment folds. They are distinguished by the geometric relationships between the fold and fault shape, which are driven by differences in the nature of fault and fold growth. The proper recognition of the folding style present in a natural structure, and the mechanical conditions that lead the development of these different styles, are the focus of this research. By taking advantage of recent increases in the availability of high-quality seismic reflection data and computational power, we seek to further develop the relationship between empirical observations of fault-related fold geometries and the kinematics and mechanics of how they form. In Chapter 1, we develop an independent means of determining the fault-related folding style of a natural structure through observation of the distribution of displacement along the fault. We derive expected displacements for kinematic models of end-member fault-related folding styles...

Kinematic differences between high and low handicap golfers

Byrne, Derek; Kenny, Ian
Fonte: University of Limerick Publicador: University of Limerick
Tipo: info:eu-repo/semantics/conferenceObject; all_ul_research
ENG
Relevância na Pesquisa
36.61%
peer-reviewed; The widespread growth of golf is mainly due to its accessibility to people of all ages, socio-economic backgrounds and skill levels (Hume et al., 2005). To correspond with this increased participation, research in the area has also increased. The majority of research to date has focused on both professional and elite level golfers. However, with only 7% of male golfers falling into the category 1 group (handicap <5.5) and 53% falling into categories 3&4 (handicap 13- 24) the research does not reflect today’s average golfer (USGA, 2007). The aim of this study is to carry out a kinematic analysis of the golf swing for a category 1 and category 3&4 golfer. From this data it is possible to compare variables such as head movement, timing and delayed release of the wrist angle. METHOD: Eight healthy male golfers were divided into two groups, dependant on skill level. This was determined by each volunteers Golfing Union of Ireland (GUI) handicap. The groups consisted of four Category 1 (mean handicap 4.5 ± 0.5) and four Category 3&4 (mean handicap 17.8 ± 1.3). Following approval from the University of Limerick Ethics Committee each volunteer carried out 10 trials (golf swings) using their own driver into an indoor driving facility. Kinematic data was collected from 29 reflective markers placed on the body and the golf club using a 6-camera system (Motion Analysis Corp....

A study on the accuracy of kinematic modelling for a 3RRR compliant micro-motion stage with flexure hinges

Yong, Y.; Lu, T.F.; Handley, D.; Hu, P.
Fonte: China Machine Press Publicador: China Machine Press
Tipo: Artigo de Revista Científica
Publicado em //2004 EN
Relevância na Pesquisa
36.69%
This paper focuses on the kinematic modelling of a 3RRR micro-motion stage. This 3RRR micro-motion stage is a monolithic compliant mechanism and is designed using flexure hinges. This compliant micro-motion stage has a closed-loop parallel structure configuration. A kinematic model (analytical constant Jacobian matrix) of this stage was derived previously by the authors using the pseudo-rigid-body model and the loop-closure theory accordingly. The Jacobian matrix is used to generate a wor4kspace of the stage. This analytical workspace is much larger than a FEA (finite element analysis) workspace and an experimental workspace. This suggest that there is a loss of motion in the micro-motion stage not being modelled in the kinematic model. Therefore, FEA is carried out to investigate the rotational and the translational motions of flexure hinges. The FEA results are used to improve the accuracy of the analytical model. The improved model effectively predicts the workspace area of the stage.

Kinematic analysis and upper limb contributions to racket head velocity of elite tennis players in tennis forehand drive winner.

Pedro, Bruno Miguel Machado
Fonte: Universidade Técnica de Lisboa Publicador: Universidade Técnica de Lisboa
Tipo: Dissertação de Mestrado
Publicado em //2015 ENG
Relevância na Pesquisa
36.61%
Mestrado em Treino de Alto Rendimento; The aim of the present study was to quantify and compare kinematic variables and their contributions to the racket head speed in tennis forehand winner, in the cross court and inside out direction. Mini inertial sensors (Xsens MVN) of motion capture, recorded kinematic data of six elite tennis players (ATP professionals). Linear velocity of the racket and ball were captured with a high speed video camera. Results indicate that the direction of the shot is influenced by the internal/external rotation of the upper arm and the abduction/adduction of the hand after the impact. Significant differences between the two directions were found in the end of the racket horizontal movement, where the players showed higher wrist abduction when playing in the inside out direction (cross court: 13.9 ± 17.2°; inside out: 16.9 ± 18.6°). Players presented a higher internal rotation of the shoulder in the inside out direction (cross court: -54.0 ± 11.8°vs. inside out: -48.0 ± 11.0°) and demonstrated an increased racket linear velocity in the cross court direction (cross court: 32.0±3.5m/s vs. Inside out: 30.3±3.8m/s). Horizontal flexion/abduction of the upper arm and flexion/extension of the forearm were the major contributors for the racket’s head speed.; Resumo: O objetivo do presente estudo foi comparar variáveis cinemáticas entre uma direita cruzada e descruzada no ténis e quantificar a contribuição do membro superior para a velocidade da cabeça da raquete Foram utilizados mini sensores inerciais (Xsens MVN) para capturar o movimento de seis atletas profissionais (ranking ATP). Para capturar a velocidade da raquete e da bola foi utilizada uma câmara de alta velocidade...

A method of increasing the kinematic boundary of air-to-air missiles using an optimal control approach

Broadston, Robert D.
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Tese de Doutorado Formato: xx, 201 p.
EN_US
Relevância na Pesquisa
36.61%
Approved for public release, distribution is unlimited; Current missile guidance laws are generally based on one of several forms of proportional navigation (PN). While PN laws are robust, analytically tractable, and computationally simple, they are only optimal in a narrow operating regime. Consequently, they may not optimize engagement range, time to intercept, or endgame kinetic energy. The advent of miniaturized high speed computers has made it possible to compute optimal trajectories for missiles using command mid-course guidance as well as autonomous onboard guidance. This thesis employs a simplified six degree of freedom (6DOF) flight model and a full aerodynamic 6DOF flight model to analyze the performance of both PN and optimal guidance laws in a realistic simulation environment which accounts for the effects of drag and control system time constants on the missile's performance. Analysis of the missile's kinematic boundary is used as the basis of comparison. A missile's kinematic boundary can be described as the maximum theoretical range at which it can intercept a target assuming no noise in its sensors. This analysis is immediately recognizable to the warfighter as an engagement envelope. The guidance laws are tested against non-maneuvering and maneuvering aircraft targets and against a simulation of a cruise missile threat. An application of the 6DOF model for a theater ballistic missile interceptor is presented.; http://www.archive.org/details/methodofincreasi00broa; Lieutenant Commander...

SIMULATED AND EXPERIMENTAL KINEMATIC CALIBRATION OF A 4 DEGREES OF FREEDOM PARALLEL MANIPULATOR

Horne, Andrew
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado
EN; EN
Relevância na Pesquisa
36.69%
This thesis discusses the kinematic calibration of the constraining linkage of a four degrees of freedom parallel manipulator. The manipulator has hybrid actuation of joints and wires, however the wires are not considered in this calibration. Two of the passive joints of the manipulator contain sensing so the calibration of the constraining linkage can be considered. Four kinematic models are developed for the manipulator. For each of these models, an independent set of model parameters are identified through an analysis of the augmented identification Jacobian matrix. Three different methods for formulating the augmented identification Jacobian matrix are explored. For the calibration, an optical tracking system is used to track the end-effector of the manipulator. The procedure to collect the calibration data is explained and the sources of error are considered. To further analyze the sources of error, simulated input data is created and the calibration using the experimental data and the simulated data are compared. In an attempt to improve the calibration, the selection of measured poses to be used for calibration is explored. Several different pose selection criteria have been proposed in the literature and five are evaluated in this work. The pose selection criteria were applied to the experimental manipulator and also a simulated two degrees of freedom manipulator. It is found that the pose selection criteria have a large impact when few poses are used; however the best results occur when a large number of poses are used for the calibration. An experimental calibration is carried out for the manipulator. Using the joint encoders and the kinematic model...

An investigation of singularities in robot kinematic chains aiming at building robot calibration models for off-line programming

Motta,J. M. S. T.
Fonte: Associação Brasileira de Engenharia e Ciências Mecânicas - ABCM Publicador: Associação Brasileira de Engenharia e Ciências Mecânicas - ABCM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2005 EN
Relevância na Pesquisa
36.74%
Robot Calibration is a term applied to the procedures used in determining actual values that describe the geometric dimensions and mechanical characteristics of a robot or multibody structure. A robot calibration system must consist of appropriate robot modeling techniques, accurate measurement equipment, and reliable model parameter determination methods. For practical improvement of a robot's absolute accuracy, error compensation methods are required that use calibration results. Important to robot calibration methods is an accurate kinematic model that has identifiable parameters. This parameterized kinematic model must be complete, continuous and minimal. This work concerns to the implementation of techniques to optimize kinematic models for robot calibration through numerical optimization of the mathematical model. The optimized model is then used to compensate the model errors in an off-line programming system, enhancing significantly the robot kinematic model accuracy. The optimized model can be constructed in an easy and straight operation, through automatic assignment of joint coordinate systems and geometric parameter to the robot links. Assignment of coordinate systems by this technique avoids model singularities that usually spoil robot calibration results.

Topological and dimensional synthesis of planar linkages for multiple kinematic tasks

Pucheta, Martín Alejo; Cardona, Alberto
Fonte: Springer Publicador: Springer
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
ENG
Relevância na Pesquisa
36.69%
This paper presents the combined use of two systematic methods for the synthesis of planar linkage mechanisms satisfying multiple kinematic tasks. First, a Graph Theory-based method is used to exhaustively enumerate the topological alternatives for a given problem. Then each feasible alternative is automatically dimensioned using the Precision Position Method; this computation includes space and design constraints. The existing methods to synthesize multiple tasks solve, in sequence, a decomposition of the problem into single kinematic tasks. The task decomposition and the topology selection for each task are usually performed by hand. This process leads to topologies with a repeated pattern and could lead to ignoring potentially desirable topologies. This paper analyzes a design strategy for the simultaneous solution of multiple kinematic tasks. This strategy has two advantages: (i) it eliminates the need for task decomposition, and (ii) it allows the exhaustive exploration of all non-isomorphic topologies up to a defined number of links. An example of simultaneous synthesis for a double rigid-body guidance task with application to a flap-tab mechanism is shown to illustrate the methodology.; Fil: Pucheta, Martín Alejo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET- Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química (i); Argentina;; Fil: Cardona...

Efficient Factorization of the Joint-Space Inertia Matrix for Branched Kinematic Trees

Featherstone, Roy
Fonte: Sage Publications Inc Publicador: Sage Publications Inc
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.69%
This paper describes new factorization algorithms that exploit branch-induced sparsity in the joint-space inertia matrix (JSIM) of a kinematic tree. It also presents new formulae that show how the cost of calculating and factorizing the JSIM vary with the topology of the tree. These formulae show that the cost of calculating for-ward dynamics for a branched tree can be considerably less than the cost for an unbranched tree of the same site. Branches can also reduce complexity; some examples are presented of kinematic trees for which the complexity of calculating and factorizing the JSIM are less than O(n2) and O(n3), respectively. Finally, a cost comparison is made between an O(n) algorithm and an O(n3) algorithm, the latter incorporating one of the new factorization algorithms. It is shown that the O(n3) algorithm is only 15% slower than the O(n) algorithm when applied to a 30-degrees-of-freedom humanoid, but is 2.6 times slower when applied to an equivalent unbranched chain. This is due mainly to the O(n 3) algorithm running about 2.2 times faster on the humanoid than on the chain.

Kinematic control of wheeled mobile robots

Gracia,L.; Tornero,J.
Fonte: Latin American applied research Publicador: Latin American applied research
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
Relevância na Pesquisa
36.82%
A generic kinematic control, which is directly applicable to any type of wheeled mobile robot, is proposed in this work. Firstly, it is presented the kinematic models of the four common types of wheels (fixed, centered orientable, castor and Swedish) a classification of wheeled mobile robots. Afterwards, it is proposed a kinematic control scheme with three nested loops: dynamic, kinematic and planning. In particular, it is studied in depth the kinematic loop through the position control and the inverse kinematics of wheels. It is also studied indirectly the planning loop through the characterization of the references that each type of mobile robot can track with no error. Finally, the kinematic control proposed is applied to an industrial forklift in simulation and in a real situation.