scholarly journals Simultaneous Measurement Method and Error Analysis of the Six Degrees-of-Freedom Motion Errors of a Rotary Axis

2018 ◽  
Vol 8 (11) ◽  
pp. 2232 ◽  
Author(s):  
Chuanchen Bao ◽  
Qibo Feng ◽  
Jiakun Li
Keyword(s):  
Simultaneous Measurement ◽  
Error Compensation ◽  
Degrees Of Freedom ◽  
Translational Motion ◽  
Laser Interferometry ◽  
Positioning Error ◽  
Motion Error ◽  
Measuring Device ◽  
Six Degrees Of Freedom ◽  
Rotary Axis

Error measurement of a rotary axis is the key to error compensation and to improving motion accuracy. However, only a few instruments can measure all the motion errors of a rotary axis. In this paper, a device based on laser collimation and laser interferometry was introduced for simultaneous measurement of all six degrees-of-freedom motion errors of a rotary axis. Synchronous rotation of the target and reference rotary axes was achieved by developing a proportional–integral–derivative algorithm. An error model for the measuring device was established using a homogeneous transformation matrix. The influences of installation errors, manufacturing errors, and error crosstalk were studied in detail, and compensation methods for them were proposed. After compensation, the repeatability of axial and radial motion errors was significantly improved. The repeatability values of angular positioning error and of tilt motion error around the y axis and x axis were 28.0″, 2.8″, and 3.9″. The repeatability values of translational motion errors were less than 2.8 μm. The comparison experiments show that the comparison errors of angular positioning error and tilt motion error around the y axis were 2.3″ and 2.9″, respectively. These results demonstrate the effectiveness of our method and the error compensation model.

scholarly journals Simultaneous Measurement Method and Error Analysis of Six Degrees of Freedom Motion Errors of a Rotary Axis Based on Polyhedral Prism

2021 ◽  
Vol 11 (9) ◽  
pp. 3960
Author(s):  
Dong Ma ◽  
Jiakun Li ◽  
Qibo Feng ◽  
Qixin He ◽  
Yaowen Ding ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Motion Error ◽  
Six Degrees Of Freedom ◽  
Rotary Axis ◽  
Position Errors ◽  
Manufacturing Errors ◽  
Polyhedral Prism ◽  
Novel Method ◽  
Six Dof ◽  
Geometric Motion

A novel method is proposed for measuring the six degrees-of-freedom (DOF) geometric motion errors of a rotary axis based on a polyhedral prism. An error-sensitive unit which consists of a polyhedral prism and a planar reflector, is designed to carry out measurement of all six DOF errors, including the angular positioning error, the tilt motion error around the Y axis, the tilt motion error around the X axis, the radial motion error along the X and Y axes, and the axial motion error along the Z axis. The mathematical error model, including the six DOF geometric motion errors of the rotary axis, the installation errors between the polyhedral prism and the rotary axis, the manufacturing errors of the polyhedral prism, and the position errors of the sensors, are established. The effectiveness of the proposed method and the compensation model was simulated and experimentally verified.

A Family of 3-DOF Translational Parallel Manipulators1

2003 ◽  
Vol 125 (2) ◽  
pp. 302-307 ◽  
Author(s):  
Marco Carricato ◽  
Vincenzo Parenti-Castelli
Keyword(s):  
Degrees Of Freedom ◽  
Translational Motion ◽  
Parallel Manipulators ◽  
Geometric Interpretation ◽  
The Other ◽  
Six Degrees Of Freedom ◽  
Revolute Joints ◽  
Rotational Degrees Of Freedom

This article addresses parallel manipulators with fewer than six degrees of freedom, whose use may prove valuable in those applications in which a higher mobility is uncalled for. In particular, a family of 3-dof manipulators containing only revolute joints or at the most revolute and prismatic ones is studied. Design and assembly conditions sufficient to provide the travelling platform with a pure translational motion are determined and two sub-families that fulfill the imposed constraint are found: one is already known in the literature, while the other is original. The new architecture does not exhibit rotation singularities, i.e., configurations in which the platform gains rotational degrees of freedom. A geometric interpretation of the translation singularities is provided.

Sensitivity analysis of a six degrees of freedom displacement measuring device

2013 ◽  
Vol 228 (1) ◽  
pp. 158-168 ◽  
Author(s):  
Andrea Mura
Keyword(s):  
Sensitivity Analysis ◽  
Performance Analysis ◽  
Degrees Of Freedom ◽  
Stewart Platform ◽  
Inverse Kinematic ◽  
Measuring Device ◽  
Six Degrees Of Freedom ◽  
Geometrical Characteristics

Object of this paper is the performance analysis of a six degrees of freedom measuring device based on a modified Stewart platform structure. Because of the device studied in this work represents a novel application of a Stewart like platform, an investigation about its performance has been done, in order to evaluate both behaviour and characteristics of this device in different geometrical configurations. In particular, sensitivity analysis has been carried on about geometrical characteristics and displacements amplitude. To calculate the sensitivity, the inverse kinematic equations of the device have been obtained.

A Family of 3-DOF Translational Parallel Manipulators

2001 ◽  
Author(s):  
Marco Carricato ◽  
Vincenzo Parenti-Castelli
Keyword(s):  
Degrees Of Freedom ◽  
Translational Motion ◽  
Parallel Manipulators ◽  
Geometric Interpretation ◽  
The Other ◽  
Six Degrees Of Freedom ◽  
Revolute Joints ◽  
Rotational Degrees Of Freedom

Abstract This article addresses parallel manipulators with fewer than six degrees of freedom, whose employ may prove valuable in those applications in which a higher mobility is uncalled-for. In particular, a family of 3-dof manipulators containing only revolute joints or at the most revolute and prismatic ones is studied. Design and assembly conditions sufficient to provide the travelling platform with a pure translational motion are determined and two sub-families that fulfill the imposed constraint are found: one is already known in the literature, whilst the other is original. The new architecture does not exhibit rotation singularities, i.e. configurations in which the platform gains rotational degrees of freedom. A geometric interpretation of the translation singularities is provided.

scholarly journals A Method for Simultaneously Measuring 6DOF Geometric Motion Errors of Linear and Rotary Axes Using Lasers

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1764 ◽  
Author(s):  
Zheng ◽  
Feng ◽  
Zhang ◽  
Li
Keyword(s):  
Measurement System ◽  
Degrees Of Freedom ◽  
High Efficiency ◽  
Single Mode ◽  
Cnc Machine Tools ◽  
Laser Source ◽  
Cnc Machine ◽  
Motion Error ◽  
Rotary Axis ◽  
Geometric Motion

A novel method for simultaneously directly measuring six-degrees-of-freedom (6DOF) geometric motion errors of CNC machine tools was proposed, and a corresponding measurement system was developed. This method can not only be applied for measuring a linear axis, but also for a rotary axis. A single-mode fiber was used to separate the measuring unit from the laser source in order to ensure system thermal stability and measurement accuracy. The method has the advantages of high efficiency and good accuracy, and requires no complicated decoupling calculation. The positioning error of the linear axis and radial motion error of the rotary axis are measured by laser interferometry and other 5DOF geometric motion errors by laser collimation. A series of experiments were performed to verify the feasibility and effectiveness of the developed measurement system.

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