JPH0115885B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a numerical control device, and particularly to a numerical control device equipped with an improved arithmetic unit for performing helical machining, that is, simultaneous linear multi-axis and circular arc two-axis machining.

In order to control the cutting operations of machine tools, complex shapes are accurately controlled according to desired command values from numerical control devices.
Helical machining was not possible with this type of numerical control device.

FIG. 1 shows a conventional general numerical control device. In FIG. 1, machining information from an input medium 10 is read into an input section 12, and a machining trajectory and machining speed are calculated by a calculation section 14 based on this machining information. The output of the calculation section 14 is applied to the control section 16, and this control section 16 outputs a control signal to the drive section 20 based on the machining instruction command given from the operation section 18, and the drive section 20 controls the machining of the machine tool 22. Control takes place. The processing instruction command to the operation unit 18 can be formed from a manual command by an operator or other automatic control commands.

As described above, in the conventional device, the machine tool 22 is numerically controlled based on the machining information given from the input medium 10 such as a paper tape, but the machining information is converted into a machining trajectory and a machining speed signal in the calculation section 14. Ru. In normal cases, the calculation unit 14 processes the given machining information by linear interpolation and circular interpolation.

FIG. 2 shows a block diagram of the linear interpolation circuit of the calculation section 14. To the direct interpolator 24, X-axis and Y-axis movement command values X and Y are applied from integration registers 26 and 28, and a speed command F _o is applied from a register 30. Then, the linear interpolator 24 outputs distribution pulses Δx and Δy that have been interpolated based on the respective command values, and the control unit 1 in FIG.
6. The distribution pulses Δx and Δy are also applied to the integration registers 26 and 28, respectively, and the interpolation process continues until the command values X and Y become zero.

FIG. 3 shows a block diagram of the circular interpolation circuit of the calculation section 14. The interpolator 32 is the same as the direct interpolator 24 described above, and an arc length memory 34 is connected to the X input terminal of the interpolator 32 to perform circular interpolation processing.
A machining arc length signal during circular arc machining is applied from the register 36, and a speed command F _o is applied from the register 36. The arc length memory 34 is composed of a register, and stores the machining arc length L designated by the machining information for circular arc machining. Further, a reference diameter memory 38 is provided to store a reference machining diameter R _c during circular arc machining, and its output is supplied as R _c and _Ro to converters 46 and 48, which will be described later. The initial arc length L _s during arc machining is the arc length accumulation register 40.
, the initial X-axis coordinate value X _s and the initial Y-axis coordinate value Y _s
are supplied to the X value accumulation register 42 and the Y value accumulation register 44, respectively.

The interpolator 32 distributes the machining arc length signal L applied from the arc length memory 34 at a rate proportional to the speed command F _o and outputs the differential machining arc length Δl. It is converted into a linear interpolation signal based on the command value. This interpolation signal is output as distribution pulses Δx and Δy to the control section 16 in FIG. 1 in the same manner as in the linear interpolation process, and the configuration of the converter for this purpose will be described below.

The differential machining arc length Δl is added to the initial machining arc length L _s in the arc length accumulation register 40, and the cumulative machining arc length L _o , which is the output of the register 40, is added to the initial machining arc length L s by the angle converter 46.
In this step, the reference warp command R _c which is the output of the reference diameter memory 38 is calculated, and the cumulative angle θ _o which is the output thereof is supplied to the coordinate converter 48 . The coordinate converter 48 calculates the cumulative angle θ _o and the cumulative diameter command R _o of the reference diameter memory 38, and sends the cumulative X command X _o to the X difference unit 50, Y
The cumulative Y command Y _o is supplied to the differentiator 52.

In this way, the coordinate converter ₄₈ outputs new coordinate values ( _Xn ,
Yn) are calculated, and these new coordinate values are used as the old coordinate values (X _p ,
Y _p ) and the difference is calculated, and distribution pulses Δx and Δy similar to linear interpolation processing are output.

In this example _, the angle converter 46 calculates θ _o =L _o / _{R c ,} the _{coordinate converter} 48 _calculates The circuit is configured to calculate X _o −X _p Δy=Y _o −Y _p, respectively.

The circular interpolator has the above configuration, and its operation will be explained below with reference to the locus diagram in FIG. 4.
The machining command program in Figure 4 sets the center point of the machining arc as the origin, and sets the starting point of the machining arc to (X _s , Y _s ),
The end point is (X _e , Y _e ), and the processing direction is set counterclockwise.

The calculation unit 14 calculates each command value R _c , L, L _s ,
Find X _s and Y _s . That is, the reference radius R _c is R _c = √ _s ² + _s ² And in order to find the machining arc length L, first the starting angle θs and the final angle θe from the X axis are θ _s = tan ^-1 Y _s /X _s (−π≦θ _s <π) θ _e =tan ^-1 Ye/Xe (−π≦θe<π) is calculated, and then the movement command angle θ is set to θ according to the machining direction condition given as counterclockwise. It is obtained as =θ _e −θ _s +2πn (n=-1, 0, 1). The number of divisions n at this time is set to satisfy the condition 0<θ≦2π in the counterclockwise direction and −2π≦θ<0 in the clockwise direction. Then, the machining arc length L is determined from the movement command angle θ described above as L=R _c ·θ.

Next, the initial arc length L _s is obtained from the starting angle θ _s and the reference radius R _c as L _s =R _c ·θ _s .

The command values R _c , L, L _s obtained as above,
Command value X _s given from the machining command program,
Y _s is stored in each memory device such as a register shown in FIG. The reference radius memory 38 that stores the reference radius R _c outputs a reference radius command R _c and a cumulative diameter command R _o . The machining arc length L is stored in the arc length memory 34, the initial arc length _Ls is stored in the arc length integration register 40, the initial X-axis coordinate value _Xs and the initial Y-axis coordinate value _Ys are stored in the X-value integration register 42, and the Y-value integration register 42. They are stored in the registers 44, respectively, and the initial set state is completed.

Next, a speed command F _o is applied to the interpolator 32,
The differential machining arc length Δl output from the interpolator 23 in response to this speed command F _o is integrated with the initial machining length L _s in the arc length integration register 40, and the cumulative value is taken as the cumulative machining arc length L _o. The angle converter 46 is supplied. Further, the differential machining arc length Δl is the arc length memory 3
4, and the machining arc length L is sequentially subtracted. That is, in the arc length accumulation register 40, L _s +Δl
The calculations are repeated sequentially, and the arc length memory 34
Then, the calculation L-Δl is repeated and the stored value is sequentially updated.

The angle converter 46 calculates the machining angle θn by dividing the cumulative machining arc length L _o by the reference radius command R _c , and converts this machining angle θn and the cumulative radius command R _o into a new coordinate value (X _o , Y _o ). and,
These new coordinate values are calculated with the initial coordinate values X _s and Y _s and supplied as distribution pulses Δx and Δy to the control unit 16 in FIG.
The stored value of 44 is updated as X _p ′=X _p +Δn Y _p ′=Y _p +Δy.

As described above, in conventional numerical control devices, direct interpolation and circular interpolation are performed exclusively and are not processed simultaneously. In addition, in the circular interpolation process, when the starting point radius and the ending point radius are different, one of the radii is appropriately selected as the reference diameter, and the remaining distance R is linearly interpolated after the circular interpolation is completed, as shown in FIG.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to simultaneously process linear interpolation and circular interpolation to easily perform helical machining.
It is an object of the present invention to provide a numerical control device that improves circular interpolation and, when there is a difference between the starting point diameter and the ending point diameter, interpolates the difference in diameter as shown in FIG. 6 and processes it into a helical shape.

In order to achieve the above object, the present invention includes an input unit that reads machining information of a machine tool, a calculation unit that calculates a machining trajectory and machining speed based on the machining information,
In a numerical control device that has a control section that outputs a control signal to the machine tool based on the output of the calculation section and a machining instruction command from the outside, the calculation section is a linear memory that stores the direct machining length during helical machining. n pieces (n is a natural number), an arc length memory for storing the arc length of circular machining, a reference diameter memory for storing the diameter of circular machining, and a predetermined linear interpolation signal and circular differential for the linear machining length and circular machining length. The interpolator is equipped with an interpolator that distributes the machining arc length, and a converter that converts the circular differential machining arc length signal of this interpolator into a linear interpolation signal, and n linear memorizers and arc length memorizers are connected in parallel to the interpolator. is connected as an input to the converter, and the circular differential machining arc length signal output from the interpolator and the signal from the reference diameter memory are input to the converter;
It is characterized by simultaneously processing linear interpolation n-axis and circular interpolation.

Further, the present invention is characterized in that it is equipped with a radius difference memory that stores the difference in diameter between the radius of the circular arc starting point and the radius of the circular end point during circular arc machining, and the radial difference is distributed by an interpolator to perform helical interpolation. Furthermore, the interpolation speed is accelerated or decelerated in synchronization with the progress of interpolation.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings. FIG. 7 shows a preferred embodiment of the calculation section of the numerical control device of the present invention. In the present invention, the linear interpolation two-axis processing is processed simultaneously with the circular interpolation processing, and if there is a diameter difference, the diameter difference is also interpolated, so the calculation section is provided with an interpolator 32.
This interpolator 32 is a conventional linear interpolator.

In order to perform helical machining and radial difference interpolation processing, an arc length memory 3 is connected to the X input terminal of the interpolator 32.
The machining arc length signal during circular arc machining is applied from 4, and Y
A radial difference signal between the starting point radius and the ending point radius during arc machining is applied from the radial difference memory 54 to the input terminal.
A linear command memory 5 is provided at the Z input terminal and U input terminal.
A linear movement command is applied from registers 8 and 60, and a speed command Fn is applied from register 36. The arc length memory 34 is composed of a register, and stores the machining arc length L designated by the machining information for circular arc machining. The radial difference memory 54 is composed of a register, and stores the radial difference R specified by machining information for arc machining.
Reference numerals 8 and 60 consist of registers in which straight line command values Z and U for straight line machining are stored and held.

The present invention further includes a reference diameter storage device 38 for storing a reference diameter R _c during circular arc machining, and its output is supplied as the reference diameter R _c to a converter 46 to be described later. In the illustrated embodiment, the initial arc length L _s during arc machining is stored in the arc length accumulation register 40.
The initial radius R _s during arc machining is the radius integration register 56
, the initial X-axis coordinate value X _s and the initial Y-axis coordinate value Y _s
are supplied to the X value accumulation register 42 and the Y value accumulation register 44, respectively.

The interpolator 32 distributes the input machining arc length signal L, diameter difference signal R, and linear machining signals Z and U at a rate proportional to the speed F _o to obtain differential machining arc length Δl, differential machining diameter difference Δr, and straight line. Outputs interpolated signals Δz and Δu.

The linear interpolation signals Δz, Δu are the first distributed pulses Δz, Δu, similar to the linear interpolation process in conventional equipment.
At the same time as being output to the control unit 16 shown in the figure, the command values are applied to the integration registers 58 and 60, and the interpolation process continues until the command values Z and U become zero. Differential machining diameter difference Δr
is added to the initial radius R _s in the radius integration register 56, and the output thereof is supplied to the converter 48 as the cumulative radius command R _o . The differential machining arc length Δl is added to the initial machining arc length L _s in the arc length integration register 40 . Cumulative machining arc length L _o which is the output of register 40
is calculated by the angle converter 46 as the reference diameter command R _c which is the output of the reference diameter memory 38 . The cumulative angle θ _o which is the output of the angle converter 46 is the coordinate converter 48
, the cumulative diameter command R _o which is the output of the cumulative diameter register 56 is calculated. The coordinate converter 48 supplies an accumulated X command X _o to an X differentiator 50 and an accumulated Y command _Yo to a Y differentiator 52 .

In this way, the coordinate converter ₄₈ outputs new coordinate values (X _{o ,}
Y _o ) are calculated, and these new coordinate values are used as the old coordinate values (X _p ,
_Yp ), and the distribution pulses Δx and Δy are outputted, and are outputted to the control unit 16 in FIG. 1 in the same way as the distribution pulses Δz and Δu of the linear interpolation process described above.

In the embodiment, the angle converter 46 is θ _o =L _o /R _c , the coordinate converter 48 is X _o = R _o・cosθ _o Y _o = R _o・sinθ _o , and the subtractors 50 and 52 are Δx ＝X _o −X _p Δy＝Y _o −Y _p The circuit is configured to calculate respectively.

The embodiment of the present invention has the above configuration, and its operation will be explained below with reference to the locus diagram in FIG. 8. Fig. 8a is a sketch, and Fig. 8b is an XY plan view of a, and only the circular interpolation part is described.

The machining command program in Figure 8 sets the center point of the machining arc as the origin, and the starting point of the machining arc is (X _s ,
Y _s ), the end point is (X _e , Y _e ), and the machining direction is set counterclockwise.

The calculation unit 14 according to the present invention calculates each command value R _s , R _c , R, L, L s , X _s , Y _{s ,} Z, U according to the helical machining command program described above according to the following procedure. That is, the starting point radius or initial radius R _s ,
The end point radius R _e is R _s = √ _s ² + _s ² R _e = √ _e ² + _e ² Then, the larger of the starting point radius R _s and the end point radius R _e is set as the reference radius R _c , and the diameter difference R is It is determined as R = R _s - _{R e} . Next, in order to find the machining arc length L, first the starting angle θ _s and the ending angle θ _e from the X axis are θ _s = tan ^-1 Y _s /X _s (-π≦θ _s <π) θ _e = tan ^-1 Y _e /X _e (-π≦θ _e <π), and then based on the condition of the machining direction given as counterclockwise, the movement command angle θ is as follows: θ=θ _e -θs+2πn (n=- 1, 0, 1). The number of divisions n at this time is set to satisfy the following conditions: 0<θ≦2π in the counterclockwise direction, and −2π≦θ<0 in the clockwise direction, and if the arc rotation speed P is specified, The movement command angle θ is updated.

θ=θ+2πkp (k=-1, 1) Here, k=1 for counterclockwise rotation and k=-1 for clockwise rotation. The machining arc length L is determined from the movement command angle θ described above as L=R _c ·θ.

The command values R _s , R _c , R, obtained as above,
L, L _s , command values X _s , Y _s given from the machining command program, and straight line command values Z, U are stored in the respective storage devices shown in FIG. 7 mentioned above. i.e. the initial radius R _s
is stored in the radius integration register 56, the reference diameter R _c is stored in the reference diameter storage 38, the machining arc length L is stored in the arc length storage 34, the initial arc length L _S is stored in the arc length storage register 40, and the initial X-axis coordinate value _s and the initial Y-axis coordinate value _Ys are stored in the X value integration register 42 and the Y value integration register 44, and the straight line command values Z and U are stored in the straight line command registers 58 and 60, respectively, and the initial set state is completed.

Next, the speed command F _o is applied to the interpolator 32, and as described above, the interpolator 32 outputs the differential machining arc length Δl, the differential machining diameter difference Δl, and the linear interpolation signals Δz, Δu corresponding to the speed command F _o . Output.

The linear interpolation signals Δz, Δu are the first distributed pulses Δz, Δu, similar to the direct interpolation process in conventional equipment.
The signal is supplied to the control unit 16 shown in the figure. It is also simultaneously supplied to 12 straight line command registers 58 and 60 to sequentially subtract straight line commands Z and U. That is, the calculations Z-Δz and U-Δu are repeated in the linear command registers 58 and 60, and the stored values are sequentially updated.

The differential machining radius difference Δr is integrated into the initial radius R _s by the radius integration register 56, and the accumulated value is supplied to the coordinate converter 48 as the cumulative radius command R _o . At the same time, the differential machining diameter difference Δr is supplied to the diameter difference storage 54, and the diameter difference R is sequentially subtracted. In other words, in the radius integration register 56, the calculation R _s +Δr is sequentially repeated, and in the radius difference storage 54, the calculation R -
The calculation Δr is repeated and the stored value is sequentially updated.

The differential machining arc length Δl is integrated into the initial machining arc length L _s by the arc length integration register 40, and the cumulative value is supplied to the angle converter 46 as the cumulative machining arc length L _o . At the same time, the differential machining arc length Δl is Arc length conversion memory 34
is supplied and the machining arc length L is sequentially subtracted. That is, in the arc length accumulation register 40, the calculation L _s +Δl is sequentially repeated, and in the arc length memory 34, the calculation L−Δl is repeated, and the stored value is sequentially updated.

The angle converter 46 calculates the machining angle θn by dividing the cumulative machining arc length L _o by the reference diameter command R _c , and converts this machining angle θn and the cumulative diameter command R _o into new coordinates (X _o , Y _o ). and,
These new coordinate values are calculated with the initial coordinate values X _s and Y _s and supplied as distribution pulses Δx and Δy to the control unit shown in FIG.
The stored value of is updated as X _p ′=X _p +Δx Y _p ′=Y _p +Δy.

In the above interpolation process, the integral values of the differential machining arc length signal Δl, the differential diameter difference signal Δr, and the linear interpolation signals Δz and Δu, and the specified machining arc length L, radius difference R, and linear movement commands Z and U are This is repeated until they are equal. In the embodiment, the machining arc length L of the arc length memory 34 is differentiated by the machining arc length Δl, and the diameter difference memory 5
4, the diameter difference R is the differential diameter difference Δr, and the linear commands Z and U of the linear command memories 58 and 60 are the linear interpolation signal Δz,
This is performed by subtracting Δu each time the interpolation process is performed, and the arc length memory 34, diameter difference memory 54,
The helical machining process described above is repeated until the linear command memories 58 and 60 become zero.

In the embodiment shown in FIG. 8, the machining angle θn is at a constant speed regardless of the increase or decrease in the cumulative diameter _Ro , so that constant angular velocity control is performed. Therefore, when the cumulative radius R _o decreases, the arc circumferential speed also decreases. In order to keep the arc peripheral speed constant, the interpolation speed applied to the interpolator 32
F _o will be increased or decreased in synchronization with interpolation.

FIG. 9 shows an embodiment in which arc circumferential velocity is constant controlled, and a fixed diameter difference memory 62 and a speed converter 64 are added to the embodiment of FIG. The fixed diameter difference storage device 62 stores the initial value of the diameter difference R and applies an output to the speed converter 64, which becomes the initial diameter difference R _i . The speed converter 64 changes the command speed F _o as interpolation progresses and applies it to the interpolator 32 in order to control the circumferential speed of the circular arc at a constant rate.

In this embodiment, if the command speed F _o , the reference diameter R _i , and the diameter difference R are used, the speed converter 64 will operate when the end point radius is larger than the start point radius, that is, when the initial diameter difference R _i is
When R _i ≧ 0, F _n = F _o R _c / R _c - R When the end point radius is smaller than the starting point radius, that is, when the initial radius difference R _i is R _i < 0, F _n = F _o R _c / It calculates R _c −R _i +R and applies the command speed F _n to the interpolator 32.

In the above embodiment, the linear interpolation is performed using two axes, but it may be performed using multiple axes. Further, in this example, the command speed conversion is synchronized with the radius difference R to perform constant arc circumferential speed control, but if this command speed conversion is synchronized with the linear command, uniform acceleration or constant deceleration interpolation is performed.

As described above, according to the present invention, helical machining can be performed by simultaneous circular interpolation and linear multi-axis interpolation, and heart cam machining and tapered helical machining can be performed by intentionally changing the sizes of the arc start point radius and the arc end point radius. can. Further, by changing the speed along with interpolation, it is possible to control the arc circumferential speed at a constant rate.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a conventional numerical control device, FIG. 2 is a block diagram showing a detailed configuration of the linear interpolation circuit in FIG. 1, and FIG. 3 is a detailed configuration of the circular interpolation circuit in FIG. 1. FIG. 4 is a machining trajectory diagram for explaining the action in FIG. 3, FIG. 5 is a trajectory diagram showing conventional circular interpolation, and FIG. 6 is a circular arc diagram used in the numerical control device of the present invention. FIG. 7 is a block diagram showing a preferred embodiment of the calculation unit applied to the numerical control device of the present invention; FIG. 8 is a machining trajectory diagram for explaining the operation in FIG. 7; FIG. 9 is a trajectory diagram showing interpolation; This figure is a block diagram showing another embodiment in which a constant arc circumferential speed control circuit is provided in FIG. 7. The same members in each figure are given the same reference numerals, 12 is an input section, 14 is a calculation section, 16 is a control section, 20 is a drive section, 22 is a machine tool, 32 is an interpolator, 34 is an arc length memory, 38 is a reference diameter memory, 40 is an arc length accumulation register, 46 is an angle converter, 48 is a coordinate converter,
54 is a diameter difference memory, 56 is a diameter integration register, 5
8 and 60 are linear command memory devices, 62 is an initial diameter difference device, 64 is a speed converter, L is a machining arc length, Δl is a differential machining arc length, R is a radius difference amount, Δr is a differential radius difference signal, R _c is the reference diameter, R _o is the cumulative diameter, R _i is the initial diameter difference amount, Z and U are linear movement commands, and Δz and Δu are linear interpolation distribution pulse signals.

Claims (1)

[Claims] 1. An input unit that reads machining information of a machine tool, a calculation unit that calculates a machining trajectory and machining speed based on the machining information, and an input unit that calculates a machining trajectory and machining speed based on the output of this calculation unit and a machining instruction command from the outside. In the numerical control device, the calculation unit includes: (a) n linear storage means (n is a natural number) for storing linear machining lengths during helical machining; b) Arc length storage means for storing the arc length of circular machining during helical machining, (c) Radial difference storage means for storing the diameter difference machining length between the starting point and end point of circular machining during helical machining, (d) Each of the above memories (e ) An angle converter that calculates the cumulative angle from the cumulative machining arc length and the reference diameter, which are the sum of the differential machining arc length signal and the initial arc length, and the cumulative machining arc length, which is the sum of the differential machining radius difference length signal and the initial radius. a coordinate converter that calculates the coordinate values of the arc machining trajectory from the diameter and the cumulative angle, and converting means for converting a signal related to the arc into a linear interpolation signal, and the output signals from the interpolation means correspond to each other. The stored contents are corrected according to the progress of the interpolation, and the linear interpolation signal from the interpolation means and the linear interpolation signal from the conversion means simultaneously perform linear n-axis interpolation and circular interpolation. A numerical control device characterized by processing. 2. The numerical control device according to claim 1, wherein the interpolation speed is accelerated or decelerated in synchronization with the progress of interpolation.