JPS58178406A - Nc data generating device for numerical control - Google Patents

Abstract

PURPOSE:To generate less-redundancy, high-density, and high-efficiency NC data by finding data on a straight-line, circle, or arc approximating a group of numbers of sampled dot coordinates within a permissible error range. CONSTITUTION:A perpendicular is drawn from a point P3 to the circle determined by three points P1, P2, and P4 and when its length is within the permissible error range, perpendiculars are drawn from the points P2 and P4 to the circle determined by three points P1, P3, and P5 to check whether the lengths of both perpendiculars are within the permissible error range or not. Said operation is performed repeatedly until the length of a perpendicular exceeds the permissible error range, and an arc determined one stage before is regarded as NC data. Then when the angle alpha between the straight line (l) connecting the starting point Q and the ending point R of the circle and a tangent (l) running on the starting point Q or the ending point R is within the permissible error range, or when the center point of this arc exceeds a maximum command value, the arc is further approximated to the straight line connecting the starting point and the ending point together.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention generates No. data by approximating a straight line, circle, or arc from a large number of point sequence coordinates collected from a No. data creation device for numerical control, particularly a reading device such as a digitizer. Regarding what you create.

As shown in a conventional example in FIG. 1, the numerical control No. data creation device is composed of a coordinate reading device 10 such as a digitizer and an information processing device 14 including a calculation means. A stylus pen 12 attached to the reading device 10
By pressing the reading surface of the reading device 10, the coordinates of the pressed point are electrically read and sequentially input to the processing device 14. The processing device 14 has an external storage device 16 such as a magnetic disk, and approximates a large number of point sequence coordinate groups read by the coordinate reading device 10 to a large number of straight line, circle, or circular arc data groups, and from this approximated data, for example, NO. tape 1
Create the No data written in 8. Coordinate reading device 1
For example, a drawing is placed on the reading board surface of 0, and as the lines on the drawing are traced with the stylus pen 12, the coordinates of points along the lines are read. A large number of point data read in this manner are stored in the external storage device 16 after necessary corrections are made. The information processing device 14 reads the point data from the storage device 16 and performs N.

Approximate calculations are performed to create the tape.

Approximation methods include connecting all points with straight lines, 3.
There are methods such as connecting points one by one with a circle, or connecting points smoothly with circular arcs that touch each other.

By the way, in conventional numerical control data, all of the large number of point sequence coordinate groups collected by the coordinate reading device 10 are approximated to straight line, circle, or circular arc data. straight line, circle, or arc data was created (this was used to create the No. is directly proportional to the length of No. 18, and in some cases, it is necessary to limit the number of point sequences to be sampled in order to prevent it from becoming even longer due to arithmetic processing in the processing device 14. However, it is actually impossible to select and collect only the minimum necessary number of point sequences, and if the number of point sequences to be collected is forcibly limited, the outline of the figure may be misread. , there is a risk of a reading error occurring that is more serious than a simple error.For this reason, it is necessary to collect point sequences that are actually unnecessary.
As a result, a very redundant NO tape was created, and it took a very long time to create the tape.

This invention was made in view of the above-mentioned conventional problem, and its purpose is to reduce redundancy from a large number of sampled point sequences without forcibly limiting the number of sampled point sequences. \\An object of the present invention is to provide an NO data creation device for numerical control that can create NO data with high density and high efficiency.

In order to achieve the above-mentioned object, the present invention enables a large number of point sequence coordinates to be extracted from a large number of point sequence coordinates collected from a coordinate reading device such as a digitizer. Equipped with a calculation means for obtaining approximate straight line, circle, or arc data within a tolerance range, and N from the straight line, circle, or arc data obtained by this calculation means.
The present invention is characterized in that O data is created.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

First, since the configuration of an embodiment of the present invention is basically the same as the conventional configuration shown in FIG. 1, detailed explanation thereof will be omitted. However, the configuration of the calculation means included in the information processing device 14 is different from the conventional one. In other words, the calculation means starts approximation from the minimum number of point sequences required to specify straight line, circle, or arc data, and sequentially increases the number of point sequences to obtain the maximum number of points within the tolerance range. It is configured to obtain straight line or circular arc data that approximates a column. A specific example of its operation will be shown below.

First, in FIG. 2, the points indicated by P1 to P6 are the points read by the coordinate reading device, and are Pl, P2, P3, P
4, P5, and P6 (see (a))), it is determined whether the length of the perpendicular line is within the allowable error range. If it is within the range, then draw a perpendicular line from P2 and P4 to the circle determined by the three points Pl, P3, and P5 (see the same figure).
b)). If the lengths of the perpendicular lines are again both within the tolerance range, similarly, draw perpendicular lines from PI, P3, and P5 to the circle determined by P2, P4, and P6, and calculate the length of all the perpendicular lines. Check whether the value is also within the allowable error range. By repeating these operations, when a point appears where the length of the perpendicular line drawn to the circle exceeds the allowable error range, the arc determined one step earlier is used as the NO data to be output to the NO tape. do. Regarding the arc determined as above, as shown in FIG.
Direct line 1s connecting the starting point Q and ending point R of the circle! If the angle α formed by the tangent at that passes through the starting point Q or the ending point B is within the tolerance range, or if the center point of this arc exceeds the maximum command value, the arc is further transformed into a straight line connecting the starting point and the ending point. Approximate.

Note that the tolerance and angle are set arbitrarily.

In this way, unnecessary redundancy is removed from the large number of point sequence coordinates collected from the coordinate reading device, and the coordinates are approximated to a small number of point sequence coordinates extracted from them within an acceptable range. Straight line, circle or arc data is required. Therefore,
For example, many points sampled as shown in FIG. 3(,) are compressed into a small number of points as shown in FIG. 3(b).

As described above, the NO data creation device for numerical control according to the present invention does not require forcibly limiting the number of sampled point sequences.
It is possible to create high-density and highly efficient NO data that is 4% smaller.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the basic configuration of a numerical control No. data creation device, FIG. 2 is a diagram illustrating an example of the operation of the calculation means in the device according to an embodiment of the present invention, and FIG. is a diagram showing another example of operation. In the figure, the same parts are given the same reference numerals, 10 is the interrogation device, 14 is the information processing device including the calculation means, agent: Patent attorney Makoto Kuzuno - (1 other person) +6 41 Figure 2 (0) 3 (C)

Claims (1)

[Claims] (1) A straight line that approximates a large number of point sequence coordinates collected within a tolerance range by a small number of point sequence coordinate groups extracted from a large number of point sequence coordinates collected from a coordinate reading device such as a digitizer; 1. A No. data creation device for numerical control, comprising a calculation means for determining circle or arc data, and No data is created from the straight line, circle or arc data determined by the calculation means. (2. In the device according to claim (1), the calculation means starts approximation from the minimum number of point sequences necessary to specify the data of a straight line, circle, or circular arc, and calculates the number of the point sequences. It is configured to obtain straight line, circle, or arc data that approximates the maximum number of point sequences within the tolerance range by increasing the number of points by one order (characterized by closing).