Forward kinematic calibration and gravity compensation for parallel-mechanism-based machine tools

2002 ◽  
Vol 216 (1) ◽  
pp. 39-49 ◽  
Author(s):  
H Ota ◽  
T Shibukawa ◽  
T Tooyama ◽  
M Uchiyama
Keyword(s):  
Machine Tools ◽  
Parallel Mechanism ◽  
Kinematic Calibration ◽  
Gravity Compensation ◽  
Forward Kinematic

A Novel Parallel Mechanism With 3-RRUR Legs

2007 ◽  
Author(s):  
Yanwen Li ◽  
Yueyue Zhang ◽  
Lumin Wang ◽  
Zhen Huang
Keyword(s):  
Machine Tools ◽  
Parallel Mechanism ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Parallel Manipulators ◽  
Forward Kinematics ◽  
Symmetrical Structure ◽  
Forward Kinematic ◽  
Accumulated Error

This paper investigates a novel 4-DOF 3-RRUR parallel manipulator, the number and the characteristics of its degrees of freedom are determined firstly, the rational input plan and the invert and forward kinematic solutions are carried out then. The corresponding numeral example of the forward kinematics is given. This type of parallel manipulators has a symmetrical structure, less accumulated error, and can be used to construct virtual-axis machine tools. The analysis in this paper will play an important role in promoting the application of such manipulators.

Kinematic Analysis of a Novel 3-DOF Parallel Mechanism with Actuation Redundancy

2013 ◽  
Vol 816-817 ◽  
pp. 821-824
Author(s):  
Xue Mei Niu ◽  
Guo Qin Gao ◽  
Zhi Da Bao
Keyword(s):  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Rbf Neural Network ◽  
Analysis Method ◽  
Parallel Kinematic Mechanism ◽  
Redundantly Actuated ◽  
Parallel Kinematic ◽  
Forward Kinematic ◽  
Kinematic Mechanism ◽  
Kinematic Solution

Kinematic analysis plays an important role in the research of parallel kinematic mechanism. This paper addresses a novel forward kinematic solution based on RBF neural network for a novel 2PRRR-PPRR redundantly actuated parallel mechanism. Simulation results illustrate the validity and feasibility of the kinematic analysis method.

Vision‐based kinematic calibration of an H4 parallel mechanism: practical accuracies

2004 ◽  
Vol 31 (3) ◽  
pp. 273-283 ◽  
Author(s):  
Nicolas Andreff ◽  
Pierre Renaud ◽  
Philippe Martinet ◽  
Franc¸ois Pierrot
Keyword(s):  
Parallel Mechanism ◽  
Kinematic Calibration

Development of Flexible Worktable for Endmilling Based on Parallel Mechanism

2010 ◽  
Vol 447-448 ◽  
pp. 826-830 ◽  
Author(s):  
Tomohisa Tanaka ◽  
Masahiro Komori ◽  
Jiang Zhu ◽  
Yoshio Saito
Keyword(s):  
Machine Tools ◽  
Parallel Mechanism ◽  
High Accuracy ◽  
The Other ◽  
Geometrical Parameters ◽  
Basic Design ◽  
Positioning Accuracy ◽  
Accuracy Measurement ◽  
High Degree ◽  
Work Table

Parallel mechanism has many advantages, such as high stiffness, high accuracy, high degree of freedom (DOF), etc. These fine features are suitable for work table of machine tools for production of recent complicated designs. In this study, six axes linear-actuated parallel mechanism was chosen as the basic design for work table. First, geometrical parameters of the table were designed to satisfy the required movable range with minimum cutting load. Then, the work table was actually constructed and its performance was evaluated. From positioning accuracy measurement, it was found that the table is suitable to be used for machining of complicated products. On the other hand, from actual cutting tests of primitive shapes using chemical wood and measurement of the machined shapes, potential of the table for real cutting application was confirmed.

Kinematic Calibration for Redundantly Actuated Parallel Mechanisms

2004 ◽  
Vol 126 (2) ◽  
pp. 307-318 ◽  
Author(s):  
Jay il Jeong ◽  
Dongsoo Kang ◽  
Young Man Cho ◽  
Jongwon Kim
Keyword(s):  
Optimization Algorithm ◽  
Parallel Mechanism ◽  
Kinematic Calibration ◽  
Parallel Mechanisms ◽  
Geometrical Constraint ◽  
Kinematic Parameters ◽  
Angle Error ◽  
Calibration Algorithm ◽  
Redundantly Actuated

We present a new kinematic calibration algorithm for redundantly actuated parallel mechanisms, and illustrate the algorithm with a case study of a planar seven-element 2-degree-of-freedom (DOF) mechanism with three actuators. To calibrate a nonredundantly actuated parallel mechanism, one can find actual kinematic parameters by means of geometrical constraint of the mechanism’s kinematic structure and measurement values. However, the calibration algorithm for a nonredundant case does not apply for a redundantly actuated parallel mechanism, because the angle error of the actuating joint varies with position and the geometrical constraint fails to be consistent. Such change of joint angle error comes from constraint torque variation with each kinematic pose (meaning position and orientation). To calibrate a redundant parallel mechanism, one therefore has to consider constraint torque equilibrium and the relationship of constraint torque to torsional deflection, in addition to geometric constraint. In this paper, we develop the calibration algorithm for a redundantly actuated parallel mechanism using these three relationships, and formulate cost functions for an optimization algorithm. As a case study, we executed the calibration of a 2-DOF parallel mechanism using the developed algorithm. Coordinate values of tool plate were measured using a laser ball bar and the actual kinematic parameters were identified with a new cost function of the optimization algorithm. Experimental results showed that the accuracy of the tool plate improved by 82% after kinematic calibration in a redundant actuation case.

Motion Control of a Hyper Redundant Manipulator Built by Serially Connecting Many Parallel Mechanism Units with a Few DOF

2010 ◽  
Vol 4 (4) ◽  
pp. 364-371 ◽  
Author(s):  
Nobuyuki Iwatsuki ◽  
◽  
Norifumi Nishizaka ◽  
Koichi Morikawa ◽  
Koji Kondoh ◽  
...  
Keyword(s):  
Motion Control ◽  
Kinematic Analysis ◽  
Parallel Mechanism ◽  
Inverse Kinematic ◽  
Weighting Coefficient ◽  
Redundant Manipulator ◽  
Output Displacement ◽  
Spatial Parallel Mechanism ◽  
Inverse Kinematic Analysis ◽  
Forward Kinematic

This paper describes the kinematic analysis and motion control of a hyper redundant robot built by serially connecting many units with a few DOF. Each unit of the manipulator is a spatial parallel mechanism with 3 DOF and is composed of 2 stages connected with 3 linear actuators, 7 spherical joints, and a center rod. The forward kinematic analysis of the manipulator based on the forward kinematics of each unit by numerical calculation was carried out. The inverse kinematic analysis, the iterative calculation so as to converge output error while output displacement is distributed into each unit with weighting coefficient, was proposed and formulated. Motion control of the robot was theoretically and experimentally examined based on the inverse kinematics. It was confirmed that a prototype with 3 units could generate the desired trajectories.

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