A five degrees-of-freedom errors measurement system for rotary axis with reference laser for reference axis alignment

2020 ◽  
Vol 91 (7) ◽  
pp. 075101
Author(s):  
Li Liu ◽  
Zhi-Feng Lou ◽  
Yu-Bin Huang ◽  
Kuang-Chao Fan ◽  
Ji-Yun Zhang
Keyword(s):  
Measurement System ◽  
Degrees Of Freedom ◽  
Rotary Axis ◽  
Reference Axis ◽  
Axis Alignment ◽  
Reference Laser

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.

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 Low-Cost 2D Index and Straightness Measurement System Based on a CMOS Image Sensor

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5461 ◽  
Author(s):  
Alain Küng ◽  
Benjamin A. Bircher ◽  
Felix Meli
Keyword(s):  
Measurement System ◽  
Degrees Of Freedom ◽  
Low Cost ◽  
Complementary Metal Oxide Semiconductor ◽  
Cmos Image Sensor ◽  
Image Sensor ◽  
Oxide Semiconductor ◽  
Measurement Systems ◽  
Starting Point ◽  
Sensor Properties

Accurate traceable measurement systems often use laser interferometers for position measurements in one or more dimensions. Since interferometers provide only incremental information, they are often combined with index sensors to provide a stable reference starting point. Straightness measurements are important for machine axis correction and for systems having several degrees of freedom. In this paper, we investigate the accuracy of an optical two-dimensional (2D) index sensor, which can also be used in a straightness measurement system, based on a fiber-coupled, collimated laser beam pointing onto an image sensor. Additionally, the sensor can directly determine a 2D position over a range of a few millimeters. The device is based on a simple and low-cost complementary metal–oxide–semiconductor (CMOS) image sensor chip and provides sub-micrometer accuracy. The system is an interesting alternative to standard techniques and can even be implemented on machines for real-time corrections. This paper presents the developed sensor properties for various applications and introduces a novel error separation method for straightness measurements.

scholarly journals Drift Reduction of a 4-DOF Measurement System Caused by Unstable Air Refractive Index

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6329
Author(s):  
Ruijun Li ◽  
Yongjun Wang ◽  
Pan Tao ◽  
Rongjun Cheng ◽  
Zhenying Cheng ◽  
...  
Keyword(s):  
Refractive Index ◽  
Laser Beam ◽  
Measurement System ◽  
Degrees Of Freedom ◽  
Cost Effective ◽  
Control Mode ◽  
Detection Accuracy ◽  
Long Distance ◽  
Cost Effective Method ◽  
Novel Method

Laser beam drift greatly influences the accuracy of a four degrees of freedom (4-DOF) measurement system during the detection of machine tool errors, especially for long-distance measurement. A novel method was proposed using bellows to serve as a laser beam shield and air pumps to stabilize the refractive index of air. The inner diameter of the bellows and the control mode of the pumps were optimized through theoretical analysis and simulation. An experimental setup was established to verify the feasibility of the method under the temperature interference condition. The results indicated that the position stability of the laser beam spot can be improved by more than 79% under the action of pumping and inflating. The proposed scheme provides a cost-effective method to reduce the laser beam drift, which can be applied to improve the detection accuracy of a 4-DOF measurement system.

scholarly journals Development of a closed-loop fes system using a 3-d magnetic position and orientation measurement system

2002 ◽  
Vol 12 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Kenji Kurosawa ◽  
Takashi Watanabe ◽  
Ryoko Futami ◽  
Nozomu Hoshimiya ◽  
Yasunobu Handa
Keyword(s):  
Musculoskeletal System ◽  
Measurement System ◽  
Degrees Of Freedom ◽  
Closed Loop ◽  
Experimental System ◽  
Control Performance ◽  
Orientation Measurement ◽  
Position And Orientation ◽  
Position And Orientation Measurement ◽  
Freedom Movement

We have developed a closed-loop FES system using a magnetic 3-D position and orientation measurement system (FASTRAK, Polhemus Inc). The purpose of this development was to resolve some experimental difficulties involved in our previous goniometer-based experimental system. The new system enabled us to perform FES control experiments on the multi-joint musculoskeletal system of the upper limbs including forearm pronation/supination. In this paper, we evaluated the system by some single-joint tracking tasks in order to compare its control performance with that of the previous system. Four muscles (ECRL(B), ECU, FCR, and FCU) of neurologically intact subjects were stimulated to control the wrist joint's two degrees of freedom movement. Stimulation currents were determined by a multi-channel PID controller that was designed for a musculoskeletal system with redundancy (i.e. the number of muscles stimulated is more than that of the degree-of-freedom of the movement). The results showed that the system had sufficient control performance on tracking desired trajectories. Moreover, the system could compensate for unwanted external disturbances.

Three-degrees-of-freedom measurement system for measuring straightness errors and their position based on the Faraday effect

2020 ◽  
Vol 59 (3) ◽  
pp. 764 ◽  
Author(s):  
Enzheng Zhang ◽  
Xueying Teng ◽  
Benyong Chen ◽  
Shihua Zhang ◽  
Zhaoyang Li
Keyword(s):  
Measurement System ◽  
Degrees Of Freedom ◽  
Faraday Effect ◽  
Three Degrees Of Freedom

A Calibration Approach for Installation Error of Multi-Axis Laser Interferometer

2017 ◽  
Author(s):  
Shengwu Du ◽  
Jinchun Hu ◽  
Yu Zhu ◽  
Chang Tian ◽  
Ming Zhang
Keyword(s):  
Laser Beam ◽  
Computational Model ◽  
Measurement System ◽  
Laser Interferometer ◽  
Measurement Information ◽  
Error Source ◽  
Reference Axis ◽  
Ultra Precision ◽  
Simulation Results ◽  
Calibration Approach

Multi-axis laser interferometer is generally employed in measuring multi-degree-of-freedom (M-DOF) displacement for many ultra-precision X-Y stages. In multi-axis measurement system, the installation deviation of interferometer laser beam is an important error source. In this paper, a novel calibration approach without other higher precision sensors has been presented, to calibrate the installation deviation in a 3-DOF displacement measurement system, with potential capability of calibrating 6-DOF measurement system. In the proposed method, one redundant measuring axis that is set as installation reference axis is added to the original 3-axis measurement system. Correspondingly, considering the installation deviations of 3-axis interferometer, a new displacement computational model with four equations is built. In this model, all installation deviations are constants and the displacement values are variable. Utilizing the redundant measurement information of three position points, the installation deviations are separated. The simulation results validate its feasibility. This approach can strictly ensure the parallelism and perpendicularity between measuring axes, and is easily applied to engineering.

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