Contouring Error Based Velocity Planning And Control For High-speed Machining

In the rapid development of modern processing and manufacturing, people want toimprove the efficiency of processing for increasing the number of the productions. Atthe same time, people also concern more about the quality of the productions. For thequality of the production depends more on the gap between the actual contour and thedesired contour, it is more concern about the contour error in the thesis.The importance of the feed-rate in the contour error control is analyzed in thethesis first, and the velocity planning based on the curvature is designed, the main ideais the velocity is inversely proportional to the curvature. The two methods areBang-Bang control and the Normalization control, and in the simulation experiment, theNormalization method is used to verify the effect of the velocity planning.The key part of the thesis is the estimation method of the contour error, the tangentapproximation method, the circle approximation method and the polar coordinationmethod are analyzed and researched, and put forward an improved method whichcombined the advantages of the three methods above. The task coordinate frame isestablished at the desired point, and the inscribed circle is also established at the desiredposition with the polar coordination in it. This improved method can control thetracking angle, and make up the weakness of the large estimation error when thetracking angle is too large. The theoretical analysis and derivation is presented in thethesis and the controller is based on the plant. The improved method is verified in thesimulation experiment and the actual experiment.Finally, it is need to identify the model of the plant before doing experiment, theChaos signal is used to be the input signal and the model of the plant is identified to getthe specific controller for the actual experiments. The circle and the ellipse contour areused to be the tracking contours. It can be find that the improved method can do thebetter effort than the circle approximation method at the higher feedrate, the contourerror can be decreased twenty percent. the improved method also can control thecontour error better than the tangent approximation method at lower and higher speed,and in condition of high speed, the contour error can be decreased more than twentypercent.