The interpolation principle of numerical control lathe, rounding
Interpolation principle of numerical control lathe, a release date: 2015 - 06 - 18 clicks: 3034 times in the actual processing, CNC lathe processed workpiece contour shapes, strictly speaking, in order to meet the accuracy requirement of the geometry size, cutting tool center path should be accurately according to the outline shape of workpiece to generate, for simple curve nc system can be relatively easy to implement, but for more complex shapes, if direct generation can make algorithm becomes very complex, computer work also correspondingly increases greatly, therefore, in practical application, often with a short straight line or arc fitting can meet the precision requirement ( Also has the need to parabola and the situation of the high order curve fitting) The fitting method is & other; Interpolation & throughout; , essentially the process of data interpolation is close. CNC lathe interpolation task is according to the requirement of the feed rate, starting point and end point in the contour coordinates to calculate the number of intermediate point between, time needed for each intermediate point calculation directly affect the speed of system control, and the calculation precision of interpolation point coordinate values among and affect the control precision of the numerical control system, therefore, interpolation algorithm is the core of the numerical control system. Interpolation algorithm, after decades of development matures, a lot of more phyletic. Generally speaking, from the mathematical model, mainly has linear interpolation and quadratic curve interpolation, etc. From interpolation calculation of the output value forms, there are mainly the pulse increment interpolation ( Also known as the basic pulse interpolation) And data sampling interpolation. The pulse increment interpolation and data sampling interpolation from one characteristic, this article respectively according to different applications of the developed pulse increment interpolation and data sampling interpolation. 1, the digital integral interpolation digital integral interpolation is one of the pulse increment interpolation. The following will be the first to describe the working principle of the pulse increment interpolation. 2, the pulse increment interpolation pulse increment interpolation is scalar interpolation, interpolation end to create a stroke increment each time, in the form of pulse output. The interpolation algorithm is mainly used in open-loop CNC system, constantly in the process of interpolation calculation to each coordinate axis coordinate feed pulse, drive motor sports. A pulse generated by the axis movement is called the pulse equivalent. Pulse equivalent is the basic unit of the pulse distribution, according to the machining precision of machine tool design, selected ordinary precision machine tool generally take pulse equivalent to: 0. 01 mm, the precision of machine tools to take 1 or 0. 5. Using the pulse increment interpolation algorithm of numerical control system, the main axis feed speed limited by interpolation program running time, general is 1 ~ 3 m/min. The pulse increment interpolation point by point comparison method, data points interpolation method, etc. Point by point comparison method was originally called area criterion, or algebraic operation method, or drunk step approximation method. The principle of this method is that the computer in the control process and point by point to calculate discriminant processing deviation, and to control the feeding, coordinate graphics processing according to the rules out the required artifacts, with step motor or electric hydraulic pulse motor drive machine, the feeding way is step by step, interpolation control machine tool. Point by point comparison method can realize linear interpolation can not only realize circular arc interpolation, its characteristic is operation intuitive, interpolation error is less than one pulse equivalent, uniform output pulse, the speed change is small, convenient adjustment, so the two coordinates is common used in open-loop CNC system. But this method cannot realize multi-axis linkage, the scope of its application is limited by a lot.