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Papers by Tarcisio Coelho

Jatoba is a legume whose seeds have dormancy, which is caused by a blockage represented by the re... more Jatoba is a legume whose seeds have dormancy, which is caused by a blockage represented by the resistance and impermeability of the tegument. This impediment prevents gas exchange and the seed of the water flow with the external environment, which prevents germination and emergence of seeds evenly. The aim of this study was to evaluate the most efficient method of breaking dormancy in jatoba seeds. The seeds were submitted to the following treatments: Mechanical scarification on the side of the thread; Mechanical scarification on the side opposite the thread; Chemical Scarification with sulfuric acid (H2SO4) for 15 minutes; Immersion of seeds in hot water for 5 minutes; Immersion the seeds in hot water for 25 minutes; Pre-Soak in water for 24 hours; and Control Treatment. Seeds were sown in commercial substrate in an open environment, the plots were distributed in a completely randomized design with four replicates, each plot was scored 20 seeds. Forty-five days after planting was c...

Lecture Notes in Mechanical Engineering, 2018

Robot Manipulators have been employed in many types of industries, such as pharmaceutical, chemic... more Robot Manipulators have been employed in many types of industries, such as pharmaceutical, chemical, automotive, aerospace, etc. A manipulator is a mechanism used to move an object along a given trajectory. Topologically, the mechanism can be constituted by parallel or serial chains. The serial kinematic chain is constituted by links connected sequentially by joints. The aim of this work is to obtain a qualitative comparison among three approaches typically applied to the modelling of multibody mechanical systems. The chosen system is a 5-DOF serial robot manipulator and the three approaches are based on the use of Lagrange’s, Maggi’s and Kane’s equations. The purpose of the modelling is to obtain the equations of motion for this serial robotic manipulator. Some numerical simulations are performed to illustrate how the obtained models can be used to predict the dynamic behavior of the chosen system.

Advances in Mechanism Design III, 2021

A manutencao e o ajuste de maquinas nas industrias podem enfrentar problemas recorrentes, alarmes... more A manutencao e o ajuste de maquinas nas industrias podem enfrentar problemas recorrentes, alarmes de maquinas muitas vezes tem solucoes conhecidas, mas depender da memoria de quem achou a solucao pode ser uma atitude arriscada. Desenvolver um aplicativo para dispositivos moveis que seja integrado com banco de dados e que sincronize com outros celulares da mesma empresa, que seja organizado de forma que quem usar, saiba chegar ate a solucao de forma rapida e direta, pode ser uma solucao eficaz contra alarmes e defeitos reincidentes, assim como pode ajudar nos ajustes das maquinas. O aplicativo do dispositivo movel foi desenvolvido para a plataforma Android e o programa do servidor usado para sincronizar com outros celulares foi desenvolvido em Java. Integracao com banco de dados SQL foi fundamental para atingir a organizacao esperada. Diagramas UML baseados no padrao MVC (Model-View-Controller) serviram de base para o desenvolvimento do aplicativo. O aplicativo foi muito bem elogiado...

Proceedings of the 25th International Congress of Mechanical Engineering, 2019

Future Internet, 2019

This is a study of the way in which YouTubers’ media metrics influence the effect of their one-si... more This is a study of the way in which YouTubers’ media metrics influence the effect of their one-sided messages (1SMs) and two-sided messages (2SMs), providing theoretical explanations based on the elaboration likelihood model. Its main objective is the proposition and testing of: (i) the interaction effect between type of message and media metrics of the YouTuber on customers’ responses, and (ii) the moderation of individuals’ conformity intention for the interaction effect between type of message and media metrics on customers’ responses. The results of an experiment showed that high YouTubers’ media metrics have more effect for 1SMs and less effect for 2SMs. Additionally, conformity intention moderates the effect of the interaction type of message X media metrics. A high level of conformity intention neutralizes the interaction effect between YouTubers’ media metrics and message sidedness. This study makes a theoretical contribution to research into online content and information u...

Procceedings of the 24th ABCM International Congress of Mechanical Engineering, 2017

International Journal of Mechanisms and Robotic Systems, 2016

Adaptive balancing means that the mechanical structure of the manipulator is modified in order to... more Adaptive balancing means that the mechanical structure of the manipulator is modified in order to achieve the decoupling of dynamic equations. This work deals with a systematic formulation for the adaptive balancing. Basically, two traditional balancing techniques are employed here: the addition of counterweight and counter-rotating disks coupled to the moving links. In addition, the feasibility of the dynamic decoupling for three distinct types of serial manipulators is discussed regarding the achievement of such balancing and the complexity level of the modified mechanical structure. The balancing conditions are developed here for 3-dof spatial and planar open-loop kinematic chain mechanisms, whose topologies are composed of revolute and prismatic joints.

Este trabalho apresenta uma abordagem pratica dos requisitos para programacao de um CLP para aten... more Este trabalho apresenta uma abordagem pratica dos requisitos para programacao de um CLP para atender a uma celula robotizada de inspecao final e classificacao de bielas, com foco nos sinais trocados entre o CLP, o robo e os perifericos. Apresenta exemplos de sinais necessarios para estruturar a logica de comandos enviados ao robo e aos perifericos.

Proceedings of the 23rd ABCM International Congress of Mechanical Engineering, 2015

Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2015

Over the past half-century, the increasing use of computational tools for mathematical modelling ... more Over the past half-century, the increasing use of computational tools for mathematical modelling and simulation was responsible for significant advances in the area of Multibody System Dynamics. However, there is still a high dependence on the use of proprietary software in this area. Noticing that most of the complex multibody systems share many components and subsystems, this paper aims to propose a modular modelling methodology in which the starting points are some already known mathematical models of subsystems and the corresponding descriptions of the constraints existing among them. The proposed algorithm is based on the computation of some orthogonal complements of Jacobian matrices, derived from the constraint equations among the subsystems, leading to a minimal system of equations without requiring the use of undetermined multipliers or generalized constraint forces. Such an algorithm can be implemented using general-purpose (eventually open source) software packages or pro...

Dynamic Balancing of Mechanisms and Synthesizing of Parallel Robots, 2016

Balancing is an important issue related to the design of mechanical systems in general, and also ... more Balancing is an important issue related to the design of mechanical systems in general, and also parallel mechanisms, in particular. In fact, the performance of parallel mechanisms associated with specific applications depends on the choice of the balancing method, namely, either static or dynamic, either passive or active, whether it is valid for a given trajectory or even for any motion. The main contribution of this work is to highlight the importance of the dynamic modelling process in order to achieve the compensation conditions associated with the chosen balancing technique. Due to the fact that parallel mechanisms have highly complex structures, the use of dynamic formalisms that employ redundant generalized coordinates, in association with the successive coupling of additional balancing elements to the original system model, can bring remarkable benefits. Additionally, this book chapter also discusses the impact of the dynamic model, developed in accordance with the methodology shown here, for the control strategy of parallel mechanisms. Finally, the simulation results demonstrate how effective is the presented methodology for the planar 5-bar with revolute joints (5R).

Mechanisms and Machine Science, 2015

The paper presents an asymmetric three-degree-of-freedom parallel mechanism purposely conceived a... more The paper presents an asymmetric three-degree-of-freedom parallel mechanism purposely conceived as a robotic device for tool positioning applications. The kinematic structure of the mechanism contains one central passive limb that constrains the end-effector motion to two translations and one rotation. This work deals with important issues related to the parallel mechanism, such as the position kinematics analysis and the singular configurations prediction.

5th IEEE RAS/EMBS International Conference on Biomedical Robotics and Biomechatronics, 2014

This work deals with the development of a controller for a robotic platform conceived as a rehabi... more This work deals with the development of a controller for a robotic platform conceived as a rehabilitation device for the human upper limb. The mechanical system is a three-degree-of-freedom parallel mechanism which is coupled to the actuators, three DC-motors and the driversthat provides the desired control signals (position, velocity and current). Regarding the control system, two techniques are utilized: the computed torque control for the motion control and the impedance control for force control. Simulations are performed in MatLabsoftware in order to evaluate the interaction with a user.