Specifically, the method of approaching a given trajectory with a short straight line is to divide the contour curve into several small straight line segments, and calculate the moving distance of each axis in the next interpolation period according to the coordinate increment of each axis participating in the interpolation movement in each interpolation period. In this way, through the connection of several small straight lines, we can approach the given trajectory and achieve the purpose of interpolation.
In the process of linear interpolation, it is necessary to control multi-axis linkage to complete linear motion. This can be achieved by selecting the shaft number/shaft group through basic instructions. At the same time, linear interpolation also has the characteristics of selecting axis number/axis group through basic instructions, controlling multi-axis linkage and completing linear motion.
Linear interpolation is a commonly used interpolation method on lathe.
In this way, the interpolation between two points is approximated by a set of points along a straight line, and the movement of the tool is controlled along this straight line. The linear interpolation algorithm adopts data sampling method. The interpolation uses a short straight line to approximate a given trajectory, and the interpolation output is the distance to be moved by each axis in the next interpolation cycle. Therefore, it is not necessary to interpolate every pulse equivalent, and a higher feed speed can be achieved.
The principle of data sampling is to use the idea of time division. According to the feed speed f and the interpolation period t, the contour curve is divided into a contour step length l, where l=ft, and then the coordinate increment of each axis participating in the interpolation movement in each interpolation period is calculated.