Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
Tải xuống
Tham khảo tài liệu 'theory and design of cnc systems part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 196 6 Numerical Control Kernel tion period. The details of each part are as follows. In the first part a the length of the approximating line segment and 8 the angle between the start point and the end point of arc are computed by the Improved Tustin algorithm. Strictly speaking a is the angle between the start point and the end point of the approximated line segment as shown in Fig. 3.24. Furthermore the number of line segments is calculated by dividing 8 from the Improved Tustin algorithm by a where 8 may not be an exact multiple of a. In this case modification of a is needed in order for 8 to be a multiple of a. This task is necessary to make the length of the line segments equal and in consequence to make a uniform feed. To perform this task we implemented the following method. Because a is proportional to the chordal error a has to be decreased so that the distance between any point on the line segment and the circle does not exceed the specified chordal error. Consequently the best way is to decrease the number of line segments by one and to compute a new a by dividing 8 by the decreased number of line segments. Finally with the newly computed a the start point of the arc and the center point of the arc it is possible to obtain the final start and end points of the line segments. In the second part the line segments from the first part are divided into small line segments based on the feed and the iteration time of interpolation. Dividing the principle line segments into small line segments is done in the same way as interpolating the linear profile line block in the linear interpolator. The line segments into which an arc is approximated are equal to the linear profile line block and the small line segments determine the displacement of the axis movement within each interpolation iteration time. 6.2.2.3 Input and Output of the Interpolator In this section the implemented data structure to store the input and output of Rough Interpolator is addressed. Rough .