| Author: | Hou, Nengjie |
| Title: | A novel Integrated Sensing System (ISS) for monitoring kinematic errors of a precision linear slide |
| Degree: | M.Sc. |
| Year: | 2012 |
| Subject: | Coordinate measuring machines. Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Mechanical Engineering |
| Pages: | xvi, 132 leaves : ill. (some col.) ; 30 cm. |
| Language: | English |
| Abstract: | Coordinate measuring machines (CMMs) are getting more and more important in modern precision process factories. In order to improve the accuracy and reliability of CMMs, both the kinematic and thermal errors of the CMM axes have to be continuously monitored and compensated in the measurement process. This dissertation proposes a novel method and develops an Integrated Sensing System (ISS) to on-machine determine the three error components of a precision linear slide: the straightness motion, the yawing and the rolling errors under the effect of thermal distortion caused by friction and drive. In this dissertation, the working theory and system of ISS are first introduced. Then, an illustrative model of a linear working machine slide is built for computer simulation. It consists of eight distance sensors installed in a stationary stage, and the other five temperature sensors mounted at various parts of the working machine. The stationary stage is mounted opposite to the profile of the moving slide axis, and the distance sensors are located on the stage to capture the distance data for eight particular points. An error separation algorithm in this novel method is developed based on Fourier series techniques. A pre-built thermal error model based on thermal modal analysis is used to obtain the thermal behavior of different machine components, and the temperature sensors are located at designated point found by thermal modal analysis. Then thermal looping technique is used to estimate the total thermally-induced profile variations of the slide. The Fourier series technique is then applied to the pre-processed outputs of the distance sensors to obtain the profiles and the kinematic errors after thermal analysis. At last, computer simulation is used to evaluate the effectiveness of the ISS by comparing the calculated results with the pre-defined inputs with thermal compensation and without thermal compensation under different conditions. Results confirm that the accuracy of CMM can be well improved when the thermal error has been taken into account in the analysis. |
| Rights: | All rights reserved |
| Access: | restricted access |
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| File | Description | Size | Format | |
|---|---|---|---|---|
| b25263912.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 2.86 MB | Adobe PDF | View/Open |
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