988 research outputs found
Kinematic and Dynamic Analysis of the 2-DOF Spherical Wrist of Orthoglide 5-axis
This paper deals with the kinematics and dynamics of a two degree of freedom
spherical manipulator, the wrist of Orthoglide 5-axis. The latter is a parallel
kinematics machine composed of two manipulators: i) the Orthoglide 3-axis; a
three-dof translational parallel manipulator that belongs to the family of
Delta robots, and ii) the Agile eye; a two-dof parallel spherical wrist. The
geometric and inertial parameters used in the model are determined by means of
a CAD software. The performance of the spherical wrist is emphasized by means
of several test trajectories. The effects of machining and/or cutting forces
and the length of the cutting tool on the dynamic performance of the wrist are
also analyzed. Finally, a preliminary selection of the motors is proposed from
the velocities and torques required by the actuators to carry out the test
trajectories
Kinematic and Dynamic Analyses of the Orthoglide 5-axis
International audienceThis paper deals with the kinematic and dynamic analyses of the Orthoglide 5-axis, a five-degree-of-freedom manipulator. It is derived from two manipulators: i) the Orthoglide 3-axis; a three dof translational manipulator and ii) the Agile eye; a parallel spherical wrist. First, the kinematic and dynamic models of the Orthoglide 5-axis are developed. The geometric and inertial parameters of the manipulator are determined by means of a CAD software. Then, the required motors performances are evaluated for some test trajectories. Finally, the motors are selected in the catalogue from the previous results
On the optimal design of parallel robots taking into account their deformations and natural frequencies
This paper discusses the utility of using simple stiffness and vibrations
models, based on the Jacobian matrix of a manipulator and only the rigidity of
the actuators, whenever its geometry is optimised. In many works, these
simplified models are used to propose optimal design of robots. However, the
elasticity of the drive system is often negligible in comparison with the
elasticity of the elements, especially in applications where high dynamic
performances are needed. Therefore, the use of such a simplified model may lead
to the creation of robots with long legs, which will be submitted to large
bending and twisting deformations. This paper presents an example of
manipulator for which it is preferable to use a complete stiffness or vibration
model to obtain the most suitable design and shows that the use of simplified
models can lead to mechanisms with poorer rigidity
Dynamics of the Orthoglide parallel robot
Recursive matrix relations for kinematics and dynamics of the Orthoglide
parallel robot having three concurrent prismatic actuators are established in
this paper. These are arranged according to the Cartesian coordinate system
with fixed orientation, which means that the actuating directions are normal to
each other. Three identical legs connecting to the moving platform are located
on three planes being perpendicular to each other too. Knowing the position and
the translation motion of the platform, we develop the inverse kinematics
problem and determine the position, velocity and acceleration of each element
of the robot. Further, the principle of virtual work is used in the inverse
dynamic problem. Some matrix equations offer iterative expressions and graphs
for the input forces and the powers of the three actuators
An Overview of Kinematic and Calibration Models Using Internal/External Sensors or Constraints to Improve the Behavior of Spatial Parallel Mechanisms
This paper presents an overview of the literature on kinematic and calibration models of parallel mechanisms, the influence of sensors in the mechanism accuracy and parallel mechanisms used as sensors. The most relevant classifications to obtain and solve kinematic models and to identify geometric and non-geometric parameters in the calibration of parallel robots are discussed, examining the advantages and disadvantages of each method, presenting new trends and identifying unsolved problems. This overview tries to answer and show the solutions developed by the most up-to-date research to some of the most frequent questions that appear in the modelling of a parallel mechanism, such as how to measure, the number of sensors and necessary configurations, the type and influence of errors or the number of necessary parameters
Kinematics of A 3-PRP planar parallel robot
Recursive modelling for the kinematics of a 3-PRP planar parallel robot is
presented in this paper. Three planar chains connecting to the moving platform
of the manipulator are located in a vertical plane. Knowing the motion of the
platform, we develop the inverse kinematics and determine the positions,
velocities and accelerations of the robot. Several matrix equations offer
iterative expressions and graphs for the displacements, velocities and
accelerations of three prismatic actuators
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