JPH0291704A - Nc machine tool - Google Patents

Abstract

PURPOSE:To machine a curve to be machined without approximating it with a straight line and an arc by composing a control signal for NC of analog signals obtained by the polynomial expansion of a function indicating a continuous curve. CONSTITUTION:A machining controller 2 is equipped with a machining program storage and arithmetic part 11, a machining program input part 12, a function expansion part 13, a Y-axial control signal decomposition part 14, a Y-axial control signal application part 15, and an X-axial control signal application part 16. Then the continuous curve indicating a machining track represented with a function, e.g. y=sinx is approximated with a polynomial consisting of a simple function group and the analog signals indicating the respective simple functions are outputted by output devices 15a-15d out put into the motor control signal. Consequently, the machining accuracy is improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides an analog control type NC (NLfneri
calControl: Numerical control) related to machine tools.

(Prior art) Generally, when using an NC machine tool to machine a complicated curve (A), (person)' as shown in Figure 3, this curve is converted into a fine straight line (B)...・Or approximate by circular arc (C)..., and these straight lines (B)... or circular arcs (C)...
Create an NC program that moves the tool along the curve M ( A), (A)' are processed.

By the way, servo systems for NC machine tools include 2'a types, which are analog servo systems and digital servo systems. The latter of these two servo systems, the digital servo system, is a system that controls position, speed, current, etc. based on digital control signals, and the transmission of control signals is extremely accurate, making it suitable for straight line machining. is suitable. However, along the path where two or more axes are specified, the continuous song number ζ
In so-called contour control for machining at a specified speed, the tool cannot machine the curved surface to be machined as it is; the coordinates of the main points must be given numerically. In this case, it is necessary to approximate the shape of the curved surface to be machined with a minute straight line or circular arc, and to perform the necessary coordinate calculations. Therefore, the work of creating an NC program obtained in this way is extremely complicated and time-consuming, which is an obstacle to reducing manufacturing costs. Moreover, as the accuracy of approximation improves, the number of groups of straight lines and circular arcs increases, resulting in an enormous amount of NC programming. Moreover, the shape machined by this NC program is only an approximate shape, and has the disadvantage of causing errors with respect to the original curved surface to be machined. On the other hand, the former analog servo method is a method that performs the control necessary for NC processing based on analog signals, and since the control signal is a continuous value, it tends to be thought that it can perform as precise control as possible. However, in reality, in order to reduce fluctuations and noise caused by external and internal conditions, it was necessary to attach an expensive electronic device. (Problem to be solved by the invention) The present invention The present invention has been developed in consideration of the above circumstances, and an object of the present invention is to provide an NC machine tool capable of machining continuous curved lines without approximating the curved surface to be machined with straight lines or circular arcs.

[Structure of the invention]

(Means and effects for solving the problem) When performing NC processing according to a continuous curve expressed as a function, the control signal for the NC is converted to a plurality of existing analog signals obtained by polynomial expansion of the functional expression representing the continuous curve. It is obtained from synthetic sandpaper.

(Example) Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the NC machine tool of this embodiment. This NC machine tool is, for example, an NC milling machine, and includes a processing device (1) that processes a workpiece (W), and a processing device (1) that operates according to a predetermined program to cut the workpiece (W) into a predetermined shape. A processing control device that processes the shape and dimension number ζ (
2) It consists of. However, the processing device (1) is
A column-shaped column part (3) is connected to the column part (3) and holds a workpiece (W).

A table part (4) that is driven in the Y direction, and a table part (4) that is provided above the table part (4) to hold a tool (5) and move it in the vertical direction (
It consists of a tool holder (6) that is driven in two directions. The table part (4) includes a table (7) that holds the workpiece (shape), an X-axis DC servo motor (8) that drives this table (7) in the X direction, and a table (7) that also drives the table (7). Y-axis DC servo motor (9) that drives in the Y direction
It has . Furthermore, the tool holder (6) includes a two-axis motor a1 that raises and lowers the tool (5) in two directions, and a two-axis motor a1 that raises and lowers the tool (5).
5) in the direction of arrow 0.
). On the other hand, the processing control device (2) includes a machine program storage/operation unit αυ in which a machine program including a functional formula (see FIG. 2) representing the motion locus of the table (7) is stored and outputs a control signal in a timely manner; The Kani program input section (1) inputs the Kani program into the Kani program memory operation section C11), and the Kani program memory operation section A reads out the stored function formula and performs, for example, Taylor expansion and simple calculation. A function expansion unit 0 decomposes into functions, and a Y-axis control signal SYl for each function expanded in the function expansion unit αj.

8Y2. The Y-axis control signal decomposition section (14) that outputs ... in parallel and the Y-axis control signal 8Y1.8Y2... from this Y-axis control signal decomposition section are combined to generate Y-axis control as an analog signal. The signal SYOζζ is combined and applied to the Y-axis DC servo motor (9th ζ).
A 2-axis control signal SzO is applied to control the X-axis control signal application unit 翺 which applies the 2-axis DC servo motor (8) to the It has a two-axis control signal applying section αη that outputs according to the nibogram. Then, the function expansion part (1
Reference numeral 3 has a computer having an arithmetic function as a main body, and is provided on the Y-axis control signal decomposition section side so as to output a deployment signal SP indicating the deployment formula. Further, the Y-axis control signal decomposition unit a4 includes an analog signal output device (15a),
(15b), . . ., and these analog signal output devices (xsa), (xsb), . . .
It consists of a function designator (1e) that selects the necessary one from among the following and gives the coefficient value at that time.And analog signal output devices (15a), (15b),
(15C), (15d), -- are each A
Functional expressions of X, BX3, OX', DX', ... (Y-axis control signal 8Y7.
SY2. It is provided to output...

Next, the operation of the NC machine tool having the above configuration will be explained.

First, a machine program for machining the workpiece (W) fixed on the table (7) of the machine program input unit α is stored in the machine program storage and calculation unit circle. This Canadian program includes a sine curve (
It contains the functional formula forming (Y=sinX) and the X and Y coordinates of the machining start point and machining end point. Next, the program memory calculation section (from 1υ), the function formula (Y=sin
The function expression signal 8F indicating the function expression Y=
sinX is Taylor-expanded as shown in the following equation (2). In this case, terms of X11 and above are omitted) (jXI X'F
I s in X-X-a, 1 + stone - 55 ...■ Omitted. From the next number ζ, the function expansion unit 3 outputs an expansion formula signal SP indicating the above expansion formula to the Y-axis control signal decomposition unit I. As a result, the Y-axis control signal decomposition unit (14 function designator (1119) that inputs this expansion formula signal SP decodes the Taylor expansion formula 15b), (15C).

(15d), (tse) and the coefficient A
,B.

The values of C, D, and H are l, -1±-16, 12, respectively.
0,5040,362880 Set. Then, an analog signal output device (15a).

(15b), (15C), (15d), (15e)
From there, the signal SYI is output to the signal applying section cL. As a result, each signal 5YISY2. sya, sy4. s
ys is synthesized with the desired Y-axis control signal 5YOl, and this Y
An axis control signal SYO is applied to the Y-axis DC servo motor (9). In synchronization with the application of this Y-axis control signal 8YO, the X-axis control signal SXO is sent to the X-axis DC servo motor (8) from the
is applied to

As a result, the table (7) moves along a trajectory as shown in FIG. On the other hand, the tool (5) is rotationally driven in the direction of arrow 0 by the tool drive motor (5a) and moves up and down in two directions according to the Z-axis control signal SzO, and moves integrally with the table (7). The workpiece (W
).

As described above, the NC machine tool of this embodiment has the following advantages. In other words, it is possible to continuously process a continuous curve expressed as a function with high precision without approximating it with a group of straight lines or a group of circular arcs. ■It is no longer necessary to approximate a continuous curve expressed as a function using a group of straight lines or a group of circular arcs.
The time required for this process is reduced. ■ ζζ huge N so that the tool moves according to the straight line group 1 circular arc group processed in above ■
There is no need to create a C program, and the creation time is shortened.

In addition, in the above embodiments, a sine curve is exemplified as the functional expression, but the function is not limited to this, and any expression can be used as long as it can be expanded into a simple polynomial. Further, in the above embodiment, Taylor's theorem is used as an expansion method, but Maclaurin's theorem may also be used for expansion. Alternatively, Fourier (Fo
urier) series. In this case, sine curve (bnsinnx) cosine curve (ancos
A dedicated analog signal output device is required to output (nx). Furthermore, in the above embodiment, the tool side is only moved in two directions, but the tool side is moved in the X and Y directions,
The workpiece may be moved in two directions. Not only the tool side and the workpiece side, respectively, x, y, z
, may be moved independently in the e direction. Furthermore, the function expansion section and the control signal decomposition section are arranged for each axis (x, y,
z).

〔Effect of the invention〕

The NC machine tool of the present invention approximates a continuous curve representing a machining trajectory expressed as a function by a polynomial consisting of a group of simple functions, and outputs an analog signal representing each simple function from a dedicated output device. Since the output analog signals are combined into one and used as the motor control signal, processing accuracy is higher than when the above continuous curve is digitally approximated by a straight line group and two circular arc groups. The preprocessing time required for program creation can be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an NC machine tool according to an embodiment of the present invention, FIG. 2 is a diagram for explaining the same operation, and FIG. 3 is an explanatory diagram of a conventional technique. ■...Workpiece, (5)...Tool. (13... Addition program input section. (13... Function expansion section. α4... Y-axis control signal decomposition section (parallel control signal generation section). ■... Y-axis control signal application section (control signal (Synthesis Department). Agent Patent Attorney Nori Chika Yudo Yudo Matsuyama Kosoku

Claims (1)

[Claims] Machining the workpiece by moving the tool relative to the workpiece according to a continuous curve expressed as a function
In the C machine tool, there is a function input part into which the functional formula of the continuous curve expressed as a function is input, a function expansion part which expands the function formula inputted by this function input part into a polynomial, and a function expansion part which expands the function formula input by this function input part into a polynomial. A parallel control signal generation section that outputs analog control signals in parallel according to each term of the polynomial, and a synthetic analog that synthesizes the analog control signals output from the parallel control signal generation section to approximate the continuous curve. An NC machine tool, comprising: a control signal synthesis section that outputs a control signal, and processes the workpiece using the synthesized analog control signal.