| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 91 ===
As the development in industry, time and quality are more and more important in manufacturing industry. Therefore, automatic manufacturing machines are tending to high speed and high precision. This thesis is aimed to eliminate tracking error of traveling a circular profile on the CNC machine tools. Friction is one of the most significant source of nonlinear disturbance for the motion control which caused by the relative motion of different contact surface at the low velocity. The nonlinear component of friction such as static friction (stiction) and the Coulomb friction should be overcome so that the tracking error will be eliminated. When the X-Y tables are tracking a circular profile, quadrant glitches appear at ninety degrees intervals, i.e. the motion of one axis has a zero velocity crossing and reverses direction.
The quadrant glitches were due to friction brought about transient phenomenon. Therefore, we will solve the transient phenomenon. We will make the system to reach steady state quickly, we may anticipate compensating a value when the motion of one axis has a zero velocity crossing and reverses direction. We will observe the system dynamic before traversing a circular profile, and to obtain a compensated value on off-line.
In addition, we designed the feedforward and P feedback tracking controllers. The research adopts feedforward controller to improve the tracking performance of the system.
Finally, the above servo loop control of tracking a circular profile on CNC machine tools is verified by the simulation and experimental results.
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