A study on intelligent control of multi-axismachine tools

• Main Authors: Shr-Chi Ou, 歐士奇
• Other Authors: Shih-Ming Wang
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/19035681064782390878

碩士 === 中原大學 === 機械工程研究所 === 95 === To obtain optimal control performance, the control parameters of a CNC machine should be changed based on different inertia and friction effects of the controlled system. However, current commercial CNC controllers can only use one set of control parameters for all applications which was initially set when machine was calibrated. In this study, the influence of inertia and friction effects to the accuracy of servo control was first investigated. Subsequently, the auto-tuning method that can on-line tune the control parameters according to change of machining condition (workpiece weight) was developed to ensure the machine can always maintain good machining accuracy Simulation was made to analyze the correlation between the two effects and the workpiece weight. Experiments with Heidenhain KGM Grid Encoder were conducted to verify the simulation results. The characteristics curve that describes the correlation between control parameters and workpiece weight was built with empirical method. The curve was used to determine the parameters when the workpiece weight was known. A weight auto-monitoring system was developed so that the updated weight of workpiece can be identified on-line for the parameter tuning. Finally, G-codes for the proposed parameter auto-tuning function and weight monitoring function were created and embedded in the CNC controller by using Macro Executor of the Fanuc controller. The G-codes enable that the parameter tuning function can be executed on-line. Experimental results have shown that the developed system can effectively improve the accuracy of machine tool.