Modelado y simulación de un robot planar paralelo activado por cables

Los robots de tipo planar activados por cables son sistemas robóticos que poseen cadenas cinemáticas cerradas. En este este documento se presenta el modelado y simulación de un sistema compuesto por un robot planar que posee cuatro cables colocados de manera paralela. La metodología desarrollada en este trabajo comienza describiendo de manera general el sistema, posteriormente se presenta la determinación de sus grados de libertad y el diagrama esquemático referente a sus articulaciones, así como también se realiza un estudio de velocidades y un análisis de singularidades. Se desarrollan las ecuaciones cinemáticas directa e inversa del sistema propuesto y, finalmente, se muestran los resultados validados de manera computacional utilizando el software Matlab Simulin

Sliding Mode Control of Cable-Driven Redundancy Parallel Robot with 6 DOF Based on Cable-Length Sensor Feedback

The sliding mode control of the cable-driven redundancy parallel robot with six degrees of freedom is studied based on the cable-length sensor feedback. Under the control scheme of task space coordinates, the cable length obtained by the cable-length sensor is used to solve the forward kinematics of the cable-driven redundancy parallel robot in real-time, which is treated as the feedback for the control system. First, the method of forward kinematics of the cable-driven redundancy parallel robot is proposed based on the tetrahedron method and Levenberg-Marquardt method. Then, an iterative initial value estimation method for the Levenberg-Marquardt method is proposed. Second, the sliding mode control method based on the exponential approach law is used to control the effector of the robot, and the influence of the sliding mode parameters on control performance is simulated. Finally, a six-degree-of-freedom position tracking experiment is carried out on the principle prototype of the cable-driven redundancy parallel robot. The experimental results show that the robot can accurately track the desired position in six directions, which indicates that the control method based on the cable-length sensor feedback for the cable-driven redundancy parallel robot is effective and feasible

Intelligent collision avoidance system for industrial manipulators

Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do ParanáThe new paradigm of Industry 4.0 demand the collaboration between robot and humans. They could help (human and robot) and collaborate each other without any additional security, unlike other conventional manipulators. For this, the robot should have the ability of acquire the environment and plan (or re-plan) on-the-fly the movement avoiding the obstacles and people. This work proposes a system that acquires the space of the environment, based on a Kinect sensor, verifies the free spaces generated by a Point Cloud and executes the trajectory of manipulators in these free spaces. The simulation system should perform the path planning of a UR5 manipulator for pick-and-place tasks, while avoiding the objects around it, based on the point cloud from Kinect. And due to the results obtained in the simulation, it was possible to apply this system in real situations. The basic structure of the system is the ROS software, which facilitates robotic applications with a powerful set of libraries and tools. The MoveIt! and Rviz are examples of these tools, with them it was possible to carry out simulations and obtain planning results. The results are reported through logs files, indicating whether the robot motion plain was successful and how many manipulator poses were needed to create the final movement. This last step, allows to validate the proposed system, through the use of the RRT and PRM algorithms. Which were chosen because they are most used in the field of robot path planning.Os novos paradigmas da Indústria 4.0 exigem a colaboração entre robôs e seres humanos. Estes podem ajudar e colaborar entre si sem qualquer segurança adicional, ao contrário de outros manipuladores convencionais. Para isto, o robô deve ter a capacidade de adquirir o meio ambiente e planear (ou re-planear) on-the-fly o movimento evitando obstáculos e pessoas. Este trabalho propõe um sistema que adquire o espaço do ambiente através do sensor Kinect. O sistema deve executar o planeamento do caminho de manipuladores que possuem movimentos de um ponto a outro (ponto inicial e final), evitando os objetos ao seu redor, com base na nuvem de pontos gerada pelo Kinect. E devido aos resultados obtidos na simulação, foi possível aplicar este sistema em situações reais. A estrutura base do sistema é o software ROS, que facilita aplicações robóticas com um poderoso conjunto de bibliotecas e ferramentas. O MoveIt! e Rviz são exemplos destas ferramentas, com elas foi possível realizar simulações e conseguir os resultados de planeamento livre de colisões. Os resultados são informados por meio de arquivos logs, indicando se o movimento do UR5 foi realizado com sucesso e quantas poses do manipulador foram necessárias criar para atingir o movimento final. Este último passo, permite validar o sistema proposto, através do uso dos algoritmos RRT e PRM. Que foram escolhidos por serem mais utilizados no ramo de planeamento de trajetória para robôs

Vision-based Modeling and Control of Large-Dimension Cable-Driven Parallel Robots

Abstract — This paper is dedicated to vision-based modeling and control of large-dimension parallel robots driven by inextensible cables of non-negligible mass. An instantaneous inverse kinematic model devoted to vision is introduced. This model relies on the specificities of a parabolic profile hefty cable modeling and on the resulting simplified static analysis. By means of a kinematic visual servoing method, computer vision is used in the feedback loop for easier control. According to the modeling derived in this paper, measurements that allow the implementation of this visual servoing method consist of the mobile platform pose, the directions of the tangents to the cable curves at their drawing points and the cable tensions. The proposed visual servoing scheme will be applied to the control of a large parallel robot driven by eight cables. To this end, in order to obtain the aforementioned desired measurements, we plan to use a multi-camera setup together with force sensors. I

Développement d'un mécanisme parallèle entraîné par câbles utilisé comme interface à retour haptique visant la réadaptation physique en environnement immersif

Les robots parallèles à câbles sont de plus en plus utilisés et étudiés, particulièrement dans le domaine de la recherche. Une des applications d'intérêts est leur usage en tant qu'interface haptique. Leur grand espace de travail et leur faible inertie en font de bons candidats pour en faire des interfaces de taille humaine. Une des applications intéressantes serait d'utiliser ce type d'interfaces dans le domaine de la santé, plus spécifiquement en réadaptation physique. Comme ces interfaces sont capables de reproduire des efforts à l'utilisateur, celles-ci peuvent être utilisées pour faire travailler les muscles. C'est dans cette optique que les recherches rapportées dans cette thèse ont été accomplies. Cette thèse présente donc premièrement des avancées plus générales aux mécanismes parallèles à câbles permettant leur utilisation en tant qu'interface haptique, pour ensuite se spécialiser dans la création d'un prototype d'interface haptique entraîné par câble combiné à un retour visuel immersif comme un casque de réalité virtuelle par exemple. La thèse se termine avec l'évaluation préliminaire du prototype développé qui est installé dans un centre de recherche en réadaptation physique et qui, dans un avenir rapproché, pourra servir à l'avancement de la recherche dans le domaine de la réadaptation physique.Cable driven parallel robots are studied and used more every day, especially in the research community. One interesting application is their use as haptic interfaces. Their big workspace and relatively low inertia makes them great candidates for human scale interfaces. One application of haptic interfaces of this scale is in health and physical readaptation. Since those interfaces are able to render forces, they can be used to train or evaluate physical capabilities. Research presented in this thesis aims at furthering knowledge in this domain. Some more general advances needed to make cable driven parallel mechanisms suitable haptic interfaces are presented first and then more specific developments toward the creation of a prototype haptic interface combined with a visual feedback are presented. The thesis ends with preliminary studies on the developed prototype installed in a research facility on physical readaptation