Application field of motion control card

Application field of motion control card

Interpolation definition

The process of determining the motion trajectory of the tool by a certain method. It can also be said that some of the data on the known curve, in accordance with the method of calculating the middle point between the known point of some algorithm, also known as the data points of the secret'.

Numerical control device according to the input of the parts of the program information, between the starting point and end point curve segment is described by spatial data density, leading to the formation of the contour, the secret data 'function is called' interpolation '.

Interpolation calculation is the numerical control device according to the input of the basic data, through calculation, describe the shape of the workpiece contour, while calculating according to the calculated results to the coordinates of a feed pulse, corresponding to each pulse, the machine bed on the response of the coordinate direction mobile a pulse when the amount of distance, and the shape of the contour of workpiece.

Linear interpolation

Linear interpolation (Interpolation Llne), which is commonly used in a lathe interpolation, in this way, the interpolation between two points along the line of the point group to approximate, along this line control tool movement. A part of the profile is often varied, there is a straight line, arc, there may be an arbitrary curve, spline. CNC machine tools are often not to go to the actual contour curve of the knife, but approximately to several small go straight knife, knife direction generally X and y. Interpolation methods: linear interpolation, circular interpolation, parabolic interpolation, spline interpolation and linear interpolation is used only for the so-called real profile is linear interpolation (if not straight, can also use the approximation curve with a line segment to approach, to each line segment you can use the linear interpolation). Assuming that a short walk in the actual contour starting point along the direction of X (one pulse equivalent), found in the end below the actual contour, then the next line along the Y direction of a short, if the line segment end is still real Outline below, then continue to walk along the Y direction for a short, until after the actual contour above, and then to the X direction go a short, cycle followed by analogy. Until the contour endpoint is reached. In this way, the actual contour by a section of the line splicing and, although the line, but if each of us a tool path segments are very small (in the range of allowable accuracy), then this section of the line and the actual contour can still approximately as the same curve -------- this is linear interpolation.

Circular interpolation

Circular interpolation (Circula: interpolation) this is a way of interpolation, in this way, according to point at both ends of the interpolation of digital information, calculate the actual arc approximation group, to control the cutting tool along these points movement, processing arc curve.

Real time interpolation algorithm for complex curves

The traditional CNC only provides straight line and arc interpolation, and the non straight line and circular arc curve is used to fit the line and arc. This method can lead to a series of problems, such as large amount of data, poor precision, low feed rate, and complex programming and so on, which will cause a great impact on machining quality and cost. Many people begin to look for a way to make a direct interpolation of complex free-form curves and surfaces. Scholars at home and abroad have carried out a large number of in-depth study, which also produced a lot of new interpolation methods. Such as A (AKIMA) spline interpolation, C (CUBIC) spline interpolation, Bezil (Bezier) curve interpolation, PH (Pythagorean-Hodograph) curve interpolation, B spline curve interpolation, etc.. Due to the advantages of B-spline curve, especially powerful in e­xpression and design of free form curve and surface shape, which makes people on free space curve and surface direct interpolation algorithm of studies focus on its body.