Vibration analysis of cable-driven parallel robots based on the dynamic stiffness matrix method

This paper focuses on the vibration analysis of Cable-Driven Parallel Robots (CDPRs). An oscillating model of CDPRs able to capture the dynamic behavior of the cables is derived using Lagrangian approach in conjunction with the Dynamic Stiffness Matrix method. Then, an original approach to analyze the modal interaction between the local cable modes and the global CDPR modes is presented. To illustrate this approach, numerical investigations and experimental analyses are carried out on a large-dimension 6-DOF suspended CDPR driven by 8 cables

Towards vision-based control of cable-driven parallel robots

International audienceThis paper deals with the vision-based control of cable-driven parallel robots. First, a 3D pose visual servoing is proposed, where the end-effector pose is indirectly measured and used for regulation. This method is illustrated and validated on a cable-driven parallel robot prototype. Second, to take into account the dynamics of the platform and using a Cartesian pose and velocity estimator, a vision-based computed torque control is developed and validated in simulation

Senior management model applied to micro, small and medium business

Siendo Colombia un país cuya economía se soporta en empresas de pequeña escala, donde las MIPYMES en conjunto representando el 90%, sector que genera el 73% de empleos y el 53% de la producción bruta en los diferentes sectores industriales, comerciales y de los servicios. No obstante de la importancia de este sector en la economía, muchas de ellas enfrentan una problemática que interrumpen su crecimiento y desarrollo. Este trabajo de investigación tiene como finalidad estructurar un modelo gerencial, el cual recoge aspectos importantes y valiosos a tener en cuenta por los dueños, gerentes y administradores; producto de identificar las debilidades que han impedido su crecimiento y desarrollo de manera efectiva en el campo empresarial moderno. Por lo anterior se analizó como debilidades más sentidas el desconocimiento y aplicación de teorías actuales en materia gerencial, que pueden actuar en miras de un mayor crecimiento y diversificación de sus ofertas de bienes y servicios, en este caso en el campo de los cosméticos; Soportado en los conocimientos adquiridos durante la Especialización en Alta Gerencia, se define desde un punto de vista particular pero responsable, los temas que deberían ser revisados por este tipo de empresas, para lograr la mejor comprensión y aplicación de temas tan importantes como Pensamiento Complejo, Análisis y Estudios de Competencias, Planeamiento Estratégico y Financiero, Gerencia de Mercado y Talento Humano.Colombia is a country whose economy is supported in small scale enterprises, where MIPYMES altogether representing 90%, sector that generates 73% of jobs and 53% of gross in the various sectors of industrial, commercial production and services. But the importance of this sector in the economy, many of them face problems that disrupt their growth and development. This research paper aims to structure a management model, which collects valuable and important aspects to be considered by owners and managers; product identify the weaknesses that have prevented its growth and development effectively in the modern business field. Therefore analyzed as most pressing weaknesses lack of knowledge and application of current theories in the management field, which may act in view of further growth and diversification of its offers of goods and services, in this case in the field of cosmetics; Supported the knowledge gained during the specialization in senior management, defined from a point of view responsible, but particular issues that should be reviewed by this kind of companies, to achieve better understanding and application of such important topics as complex thought, analysis and studies of competencies, strategic planning and financial, market and human resource managemen

Static Analysis of Planar 3-DOF Cable-Suspended Parallel Robots Carrying a Serial Manipulator

International audienceThis paper deals with the static analysis of a robotic system consisting of a planar 3-degree-of-freedom cable-suspended parallel robot having a 3-degree-of-freedom serial manipulator on-board its mobile platform. A static equilibrium of this system is said to be feasible when the cable tensions lie within a prescribed set of admissible values. It is shown that a static equilibrium is feasible when the horizontal coordinate of the overall center of mass lies within an interval. A method to compute the bounds of this interval is presented

Characterizations of Fullly Constrained Poses of Parallel Cable-Driven Robots: a Review

International audienceThe pose of the mobile platform of a parallel cable-driven robot is said to be fully constrained if any wrench can be created at the platform by pulling on it with the cables. A fully constrained pose is also known as a force-closure pose. In this paper, a review of three useful characterizations of a force-closure pose is proposed. These characterizations are stated in the form of theorems for which proofs are presented. Tools from linear algebra allow to derive some of these proofs while the others are more difficult and can hardly be obtained in this manner. Therefore, polyhedral cones, which are special cases of convex cones, are introduced along with some of their well-known fundamental properties. Then, it is shown how the aforementioned difficult proofs can be obtained as direct consequences of these properties

A Bounding Volume of the Cable Span for Fast Collision Avoidance Verification

part of the 5th IFToMM World CongressInternational audienceThe problem of verifying the absence of collision between a cable and the mobile part(s) of a device located on-board the mobile platform of a Cable-Driven Parallel Robot (CDPR) is addressed. The set of all positions taken by one cable of the CDPR for all the poses of the mobile platform in a prescribed workspace is called the cable span. A simple bounding volume approximation of the cable span is proposed in this paper. This bounding volume is a polyhedron and the characterization of the faces of this polyhedron is discussed. Using this polyhedron as a bounding volume of the cable span allows to accelerate computations related to collision avoidance checking

A Tension Distribution Method with Improved Computational Efficiency

International audienceThis paper introduces a real-time capable tension distribution algorithm for n degree-of-freedom cable-driven parallel robots (CDPR) actuated by n+2 cables. It is based on geometric considerations applied to the two-dimensional convex polytope of feasible cable tension distributions. This polytope is defined as the intersection between the set of inequality constraints on the cable tension values and the affine space of tension solutions to the mobile platform static or dynamic equilibrium. The algorithm proposed in this paper is dedicated to n degree-of-freedom cable-driven parallel robots (CDPR) actuated by n+2 cables. Indeed, it takes advantage of the two-dimensional nature of the corresponding feasible tension distribution convex polytope to improve the computational efficiency of a tension distribution strategy proposed elsewhere. The fast computation of the polytope vertices and of its barycenter made us successfully validate the real-time compatibility of the presented algorithm

Control of a Large Redundantly Actuated Cable-Suspended Parallel Robot

International audienceThis paper deals with the control of a 6-DOF cable-suspended parallel robot (CSPR) able to perform tasks such as pick-and-place trajectories over a large workspace. In order to maximize the ratio between the robot workspace and its overall dimensions, actuation redundancy can be used. The control of such a redundantly actuated CSPR turns to be challenging as a realtime embeddable algorithm for distributing the cable tensions should be used, together with a suitable control scheme. This paper proposes a computationally efficient tension distribution algorithm implemented within a dual-space feedforward scheme in order to properly control the moving platform. Experimentations are performed on a large 6-DOF CSPR prototype equipped with 8 actuators

Cable-Driven Parallel Robots

International audienceA Cable-Driven Parallel Robot (CDPR) is a special type of parallel robot where cables replace rigid links. Alternatively, a CDPR can be viewed as a dexterous lifting machine which uses several cables to avoid, at least partially, a sway of the payload. CDPRs generally consist of a supporting structure, winches winding up the cables, and a payload (mobile platform) where the cables are attached