Singularity Analysis of PAMINSA Manipulators

International audiencePAMINSA (PArallel Manipulator of the I.N.S.A.) is a new family of parallel manipulators from four to six degrees of freedom (DOF), which have been developed at the I.N.S.A. in Rennes. The particularity of these manipulators is the decoupling of displacements in the horizontal plane from its translation along the vertical axis. Such a decoupling improves some mechanical properties of the manipulator making it more efficient. In this paper a singularity analysis of PAMINSA with four, five and six degrees of freedom is presented. The nature of each kind of singularity is discussed

Pantopteron-4: a New 3T1R Decoupled Parallel Manipulator for Pick-and-Place Applications

International audienceIn this paper, a novel 4-DOF decoupled parallel manipulator with Schoenflies motions, called the Pantopteron-4, is presented. This manipulator is able to perform the same movements as the Isoglide4 or the Quadrupteron, but, due to its architecture which is made of three pantograph linkages, an amplification of the movements between the actuators and the platform displacements is achieved. Therefore, having the same actuators for both robots, the Pantopteron-4 displaces (theoretically) many-times faster than the Isoglide4 or the Quadrupteron, depending on the magnification factor of the pantograph linkages. Thus, this mechanism is foreseen to be used in applications where the velocities and accelerations have to be high, as in pick-and-place. First, the kinematics of the Pantopteron-4 is presented. Then, its workspace is analyzed. Finally, a prototype of the mechanism is shown and conclusions are given

Kinematic Analysis and Trajectory Planning of the Orthoglide 5-axis

The subject of this paper is about the kinematic analysis and the trajectory planning of the Orthoglide 5-axis. The Orthoglide 5-axis a five degrees of freedom parallel kinematic machine developed at IRCCyN and is made up of a hybrid architecture, namely, a three degrees of freedom translational parallel manip-ulator mounted in series with a two degrees of freedom parallel spherical wrist. The simpler the kinematic modeling of the Or-thoglide 5-axis, the higher the maximum frequency of its control loop. Indeed, the control loop of a parallel kinematic machine should be computed with a high frequency, i.e., higher than 1.5 MHz, in order the manipulator to be able to reach high speed motions with a good accuracy. Accordingly, the direct and inverse kinematic models of the Orthoglide 5-axis, its inverse kine-matic Jacobian matrix and the first derivative of the latter with respect to time are expressed in this paper. It appears that the kinematic model of the manipulator under study can be written in a quadratic form due to the hybrid architecture of the Orthoglide 5-axis. As illustrative examples, the profiles of the actuated joint angles (lengths), velocities and accelerations that are used in the control loop of the robot are traced for two test trajectories.Comment: Appears in International Design Engineering Technical Conferences \& Computers and Information in Engineering Conference, Aug 2015, Boston, United States. 201

Pantopteron: a New Fully-Decoupled 3-DOF Translational Parallel Robot for Pick-and-Place Applications

International audienceIn this paper, a novel 3-DOF fully decoupled translational parallel robot, called the Pan-topteron, is presented. This manipulator is similar to the Tripteron Cartesian parallel manipulator, but due to the use of three pantograph linkages, an amplification of the ac-tuators displacements is achieved. Therefore, equipped with the same actuators, the mobile platform of the Pantopteron moves many-times faster than that of the Tripteron. This amplification is defined by the magnification factor of the pantograph linkages. The kinematics, workspace and constraint singularities of the proposed parallel robot are studied in detail. Design considerations are also discussed and a possible prototype is illustrated.

Research and development at ORNL/CESAR towards cooperating robotic systems for hazardous environments

One of the frontiers in intelligent machine research is the understanding of how constructive cooperation among multiple autonomous agents can be effected. The effort at the Center for Engineering Systems Advanced Research (CESAR) at the Oak Ridge National Laboratory (ORNL) focuses on two problem areas: (1) cooperation by multiple mobile robots in dynamic, incompletely known environments; and (2) cooperating robotic manipulators. Particular emphasis is placed on experimental evaluation of research and developments using the CESAR robot system testbeds, including three mobile robots, and a seven-axis, kinematically redundant mobile manipulator. This paper summarizes initial results of research addressing the decoupling of position and force control for two manipulators holding a common object, and the path planning for multiple robots in a common workspace

A New 3-DoF Planar Parallel Manipulator with Unlimited Rotation Capability

International audienceMost of three-degree-of-freedom (3-DoF) planar parallel manipulators encountered today have a common disadvantage that is their low rotational capability. However, for many industrial applications, by example in automated assembly systems, cutting machines, simulators, or micro-motion manipulators, a high rotation capability is needed. To overcome such a difficulty, this paper focuses its attention on the proposal of a new 3-DoF planar parallel manipulator capable of high rotational capability. Firstly, structure and mobility of the suggested manipulator are discussed. Then the forward and inverse kinematic problems are analyzed, as well as it is disclosed its singular configurations. The shaking force and shaking moment balancing are also considered. The proposed design concept is illustrated by a driven demonstrator which is a first model of the suggested manipulator

Static force capabilities and dynamic capabilities of parallel mechanisms equipped with safety clutches

Cette thèse étudie les forces potentielles des mécanismes parallèles plans à deux degrés de liberté équipés d'embrayages de sécurité (limiteur de couple). Les forces potentielles sont étudiées sur la base des matrices jacobienne. La force maximale qui peut être appliquée à l'effecteur en fonction des limiteurs de couple ainsi que la force maximale isotrope sont déterminées. Le rapport entre ces deux forces est appelé l'efficacité de la force et peut être considéré ; comme un indice de performance. Enfin, les résultats numériques proposés donnent un aperçu sur la conception de robots coopératifs reposant sur des architectures parallèles. En isolant chaque lien, les modèles dynamiques approximatifs sont obtenus à partir de l'approche Newton-Euler et des équations de Lagrange pour du tripteron et du quadrupteron. La plage de l'accélération de l'effecteur et de la force externe autorisée peut être trouvée pour une plage donnée de forces d'actionnement.This thesis investigates the force capabilities of two-degree-of-freedom planar parallel mechanisms that are equipped with safety clutches (torque limiters). The force capabilities are studied based on the Jacobian matrices. The maximum force that can be applied at the end-effector for given torque limits (safety index) is determined together with the maximum isotropic force that can be produced. The ratio between these two forces, referred to as the force effectiveness, can be considered as a performance index. Finally, some numerical results are proposed which can provide insight into the design of cooperation robots based on parallel architectures. Considering each link and slider system as a single body, approximate dynamic models are derived based on the Newton-Euler approach and Lagrange equations for the tripteron and the quadrupteron. The acceleration range or the external force range of the end-effector are determined and given as a safety consideration with the dynamic models