JPH0887312A - Cylinder interpolation system - Google Patents

Abstract

PURPOSE: To make an actual speed after cutting point correction constant at the time of the interpolation of a curve on a cylinder surface. CONSTITUTION: A tool diameter correcting means 104 computes a tool diameter offset vector on a virtual plane, consisting of a cylinder axis and a virtual linear axis obtained by expanding the cylinder surface, to find the center path of a tool. A feed speed control means 120 calculates the actual speed variation quantity of the tool generated as a result of cutting point correction and outputs a conversion speed command, overridden so as to compensate an actual speed variation quantity, for the command speed when an interpolation command for the curve is outputted. An interpolating means 107 interpolates the center path of the tool with the conversion speed and outputs a 1st interpolation pulse of the virtual linear axis and a 2nd interpolation pulse of the cylinder axis. A pulse converting means 108 converts the 1st interpolation pulse into a 3rd interpolation pulse of the axis of rotation. Respective correction component calculating means 105 and 109, correction component interpolating means 106 and 110, and adding machines 111 and 112 constitute a cutting point correcting means and the cutting point correction is done so that the cutting surface of the tool faces the center point of a work.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical interpolation of a numerical controller for machining a cylindrical surface of a workpiece, and more particularly to a cylindrical interpolation method for correcting a cutting point so that a tool cutting surface is always perpendicular to the cylindrical surface. .

[0002]

2. Description of the Related Art In a machining center or the like, when an end mill is used to perform complicated groove machining on a cylindrical work, the cylindrical axis (Z) and the rotary axis (C) are controlled to perform the machining.
In such processing, the cylindrical interpolation method is widely adopted in order to easily create a processing program.

When performing the cylindrical interpolation method, a virtual orthogonal coordinate system, which is obtained by developing a cylindrical surface on a virtual plane and is composed of a rotation center axis of the cylinder and a virtual linear axis, is used. FIG. 6 is a diagram showing an imaginary plane expressed by expanding a cylindrical surface. Work 2
The virtual plane 2a is obtained by expanding the cylindrical surface of. Here, the rotation center axis 6 of the work 2 is the Z axis, and the axis perpendicular to the center axis of the tool 1 and the Z axis is the virtual linear axis.
This virtual linear axis is the Cy axis. Then, the virtual plane 2a
Is a coordinate diameter composed of the Z axis and the Cy axis. The movement of the virtual plane 2a in the Cy axis direction is actually controlled by the rotation center axis 6 of the workpiece 2 rotating in the C axis direction.

This coordinate system is the same as a normal plane coordinate system, and the path of the tool is obtained from the program in this orthogonal coordinate system. Since the machining shape is programmed in the cylindrical coordinate system, it is converted into the virtual rectangular coordinate system. After the Z axis and the Cy axis are interpolated in such an orthogonal coordinate system, the movement amount of the Cy axis is inversely converted into the rotation amount of the rotation axis (C axis) 6 of the work 2 (from the orthogonal coordinate to the cylindrical coordinate system). , Control the C-axis. With such a cylinder interpolation method, a complicated groove machining program can be easily created.

However, when the virtual plane is cut in the same manner as a normal plane coordinate system, there arises a problem that the cutting surface of the tool is not perpendicular to the cylindrical surface. FIG. 7 is a diagram showing a positional relationship between the tool 1 and the work 2 in grooving when the virtual plane is cut in the same manner as the plane coordinate system. In this case, the tool shaft 1a is controlled so as to be perpendicular to the cylindrical surface of the work 2. Therefore, the tool cutting surface 5 is the work 2
Has a constant angle with the line 3 perpendicular to the cylindrical surface of the. As a result, the part shown by the diagonal line 4 is cut excessively,
It was not possible to make the tool cutting surface 5 perpendicular to the cylindrical surface.

Conventionally, in order to solve this problem, cutting point correction has been performed. FIG. 8 is a diagram showing the positional relationship between the tool and the work after the cutting point correction. Tool cutting surface 5 of tool 1
However, since it coincides with the vertical line of the cylindrical surface of the work 2, the tool axis 1a is moved by the tool radius r, and cutting is performed so that the tool cutting surface 5 coincides with the point P directly above the rotation center axis of the work 2. Point correction is performed.

As described above, the tool position is corrected so that the tool cutting surface is perpendicular to the cylindrical surface from the tool contact vector which is a vector from the center of the tool to the cutting point (tool contact) of the tool. As such an example, the present applicant has filed Japanese Patent Application Laid-Open No. 4-33013.

[0008]

However, when curve interpolation such as circular arc interpolation is performed on the cylindrical surface, the tool contact vector changes every moment. Therefore, the cutting point correction amount at that time also changes at the same time. As a result, the cylindrical axis (Z axis) and the rotation axis (C
The speed of the combined speed of the shaft (hereinafter referred to as the actual speed) is not constant.

FIG. 9 is a diagram for explaining the feed rate during the cutting point correction. For ease of explanation, a virtual plane (Cy-
This will be described using the Z coordinate system). Therefore, the rotation axis (C axis)
And the virtual linear axis (Cy axis) are treated as the same.

Here, consider a case where the tool moves by the central angle Δθ per unit time by circular interpolation. That is,
After the unit time has passed from the position of the tool 1c before moving, the tool 1
Move to the position of d. At this time, the tool is in the program passage 9
The tool center path 91a is a path obtained by correcting the tool diameter to 0a.

As a precondition, the velocity component of the Z axis before the cutting point correction is Fz, and the velocity component of the Cy axis before the cutting point correction is F
c, the Cy axis component of the tool contact vector (Vs in the figure) at the position of the tool 1c before movement is Vcs, and the tool 2b after movement
The Cy-axis component of the tool contact vector (Ve in the figure) at the position is defined as Vce. At this time, each velocity component after the cutting point correction can be expressed by the following equation. The Z-axis velocity component Fz ′ after the cutting point correction is

[0012]

## EQU1 ## Fz '= Fz (1) The Cy-axis velocity component Fc' after the cutting point correction is

[0013]

Fc ′ = Fc + (Vce−Vcs) (2) The combined speed of the Z-axis speed component Fz ′ and the Cy-axis speed component Fc ′ is the actual speed.

When the cutting point is corrected, the speed after the tool radius correction (the combined speed of Fz and Fc) is equal to the command speed, and the speed (Vce) caused by the change in the cutting point correction amount is added to the speed. -Vcs) is added. Therefore, the cutting point correction amount also changes according to the change in the moving direction of the tool, and the actual speed on which the cutting point correction amount is superimposed is not constant. The actual speed is faster than the commanded speed in the case of the inside offset of the circular arc. On the contrary, in the case of the outer offset of the circular arc, it becomes slower than the command speed.

As described above, the cutting point interpolation correction amount is sequentially changed, so that the movement of the tool is not smooth and stable machining cannot be performed. As a result, there is a problem that the processing accuracy is deteriorated.

The present invention has been made in view of such a point, and when the curve interpolation such as the circular arc interpolation is performed on the cylindrical surface, the actual speed after performing the cutting point correction is a constant value. It is an object of the present invention to provide a cylindrical interpolation method that

[0017]

In order to solve the above-mentioned problems, according to the present invention, in a cylindrical interpolation method for machining on a cylindrical surface, it is composed of a cylindrical axis and an imaginary linear axis that develops the cylindrical surface. On the virtual plane, a tool radius offset vector is calculated to obtain a tool center path, and a tool interpolation that is generated by performing a cutting point correction when a curve interpolation command is output. A feed speed control means for calculating a speed change amount and outputting a converted speed obtained by overriding the command speed so as to cancel the actual speed change amount, and the converted speed to interpolate the central passage of the tool. An interpolation means for outputting the first interpolation pulse of the virtual linear axis and a second interpolation pulse of the cylindrical axis, and a pulse conversion means for converting the first interpolation pulse into a third interpolation pulse of the rotation axis. When, Cutting surface of serial tool, cylindrical interpolation method characterized by having a a cutting point correcting means for performing a cutting point correction so that the cylindrical surface perpendicular is provided.

[0018]

The tool radius correcting means calculates the tool radius offset vector on the virtual plane composed of the cylindrical axis and the virtual linear axis that is the developed cylindrical surface to obtain the central passage of the tool. When the curve interpolation command is output, the feed speed control means calculates the actual tool speed change amount caused by the cutting point correction, and overrides the commanded speed to cancel the actual speed change amount. The converted speed command multiplied by is output. The interpolation means interpolates the center passage of the tool according to the conversion speed, and outputs a first interpolation pulse of the virtual linear axis and a second interpolation pulse of the cylindrical axis. The pulse converting means is the first
Is converted into the third interpolation pulse of the rotation axis.
The cutting point correction means performs cutting point correction so that the cutting surface of the tool faces the center point of the work.

As a result, the actual speed can be maintained at a constant value.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of the cylindrical interpolation method of the present invention. The coordinate axes used in the following explanation are
It is the coordinate axis shown in FIG. The machining program 101 issues a Z-axis command and a C-axis command. Here, it is assumed that the C axis is commanded in units of angles. The decoding means 102 decodes a cylindrical interpolation or involute interpolation command, if any. The coordinate conversion means 103 converts the rotation command of the C axis into the virtual linear axis Cy on the virtual plane. That is, the coordinate commanded by the rotation angle is converted into the distance on the cylindrical surface of the work corresponding to the rotation angle.

From these commands, the tool radius correction means 104
Determines the center passage of the tool from the program passage along the Z axis and the virtual linear axis Cy and the tool diameter. Then, the command value of the central passage of the tool is output. That is, the tool diameter correction means 104
Outputs the tool movement command Z and the command Cy on the virtual linear axis to the interpolation means 107. Further, the tool radius correction means 104 sends the tool radius offset vector to the correction component calculation means 105 at the block start point, and sends the tool radius and offset direction to the synchronous correction component calculation means 109.

On the other hand, when the decoding means 102 decodes from the machining program a command such as circular interpolation or involute interpolation, in which the tool contact vector changes with time,
The feed rate (command speed) F and the arc radius R of the circular interpolation are output to the feed speed control means 120.

Further, the feed rate control means 120 receives from the tool radius correction means 104 the identification flag of the inner offset or the outer offset and the data of the tool radius. Then, the feed speed control unit 120 calculates the conversion ratio for the override, and outputs the conversion speed αFi, which is the command speed multiplied by the conversion ratio. At this time, the data of the central angle θi-1 at the time of circular interpolation is received in advance. The method of calculating the conversion ratio will be described later.

The interpolating means 107 interpolates the commands Z and Cy according to the conversion speed αFi, and the interpolation pulse P of the virtual linear axis.
Cyi and Z-axis interpolation pulse PZi are converted to pulse 1
It outputs to 08. The pulse conversion means 108 converts the interpolation pulse PCyi into the interpolation pulse PCi for the rotation axis (C axis).

Correction component calculation means 105 at the block start point
Calculates the correction component Vcy of the tool contact vector in the direction of the virtual linear axis from the tool radius offset vector. This is because the tool contact vector is obtained by reversing the direction of the tool radius offset vector, so that the tool contact vector can be obtained from the tool radius offset vector and the virtual linear axis component of the rotation vector can be obtained. The correction component Vcy is interpolated by the block start point correction component interpolation means 106 and output as a Y-axis correction pulse RYj and a rotation axis correction pulse RCj.

On the other hand, the synchronous correction component calculation means 109 calculates the correction component when the tool contact vector changes for each interpolation of the interpolation means 107, such as during circular interpolation and involute interpolation. That is, the virtual linear axis component ΔVcy of the change of the tool contact vector when the angle θi of the tool contact vector with respect to the Cy axis changes is obtained and sent to the synchronization correction component interpolation means 110. The synchronization correction component interpolating means 110 interpolates the correction component ΔVcy every time the interpolating means 107 performs interpolation calculation, and corrects the C-axis correction pulse RCi and Y.
The axis correction pulse RYi is output. These correction pulses RCi and RYi are the interpolation pulse P from the interpolation means 107.
It is output in synchronization with Ci and PZi.

The Y-axis correction pulses RYj and RYi are added by the adder 111 and sent to the axis control circuit 42 as Y-axis output pulses. Of course, the correction pulses RYj and RYi are not output at the same time.

C-axis correction pulse RCj, interpolation pulse PC
i and the correction pulse RCi are added by the adder 112 and sent to the axis control circuit 44. The correction pulse RCi is superimposed on the interpolation pulse PCi and output.

The Z-axis interpolation pulse PZi is sent to the axis control circuit 43. In this way, in the cylindrical interpolation for correcting the cutting point, when circular interpolation on the cylindrical surface is performed,
The actual speed can be the same as the commanded speed.

FIG. 2 is a block diagram of the hardware of the numerical controller (CNC) for implementing the present invention. In the figure, 10 is a numerical controller (CNC). The processor 11 is a central processor for controlling the entire numerical controller (CNC) 10, and a ROM is provided via a bus 21.
The system program stored in 12 is read, and according to this system program, the numerical controller (CNC)
10 Control of the whole is executed. The RAM 13 stores temporary calculation data, display data, and the like. SRAM is used for the RAM 13. The CMOS14 has a tool correction amount,
A pitch error correction amount, a machining program, parameters and the like are stored. The CMOS 14 is backed up by a battery (not shown) and is a non-volatile memory even when the power of the numerical controller (CNC) 10 is turned off.
Those data are retained as they are.

The interface 15 is an interface for an external device, and is connected to an external device 31 such as a paper tape reader, a paper tape puncher, and a paper tape reader / puncher. The processing program is read from the paper tape reader, and the processing program edited in the numerical controller (CNC) 10 can be output to the paper tape puncher.

A PMC (Programmable Machine Controller) 16 is built in the CNC 10 and controls the machine with a sequence program created in a ladder format. That is, according to the M function, S function, and T function instructed by the machining program, these are converted into necessary signals on the machine side by the sequence program and output from the I / O unit 17 to the machine side. This output signal drives a magnet or the like on the machine side to operate a hydraulic valve, a pneumatic valve, an electric actuator, or the like. Further, it receives a signal from a limit switch on the machine side, a switch on the machine operation panel, etc., performs necessary processing, and passes it to the processor 11.

The graphic control circuit 18 converts the current position of each axis, alarms, parameters, digital data such as image data into an image signal and outputs it. This image signal is sent to the display device 26 of the CRT / MDI unit 25,
It is displayed on the display device 26. Interface 19 is CR
It receives data from the keyboard 27 in the T / MDI unit 25 and passes it to the processor 11.

The interface 20 is the manual pulse generator 3
2 and receives the pulse from the manual pulse generator 32. The manual pulse generator 32 is mounted on the machine operation panel,
Used to precisely position machine working parts manually.

The axis control circuits 41 to 44 receive the movement command of each axis from the processor 11 and output the command of each axis to the servo amplifiers 51 to 54. The servo amplifiers 51 to 54 receive the movement command and drive the servo motors 61 to 64 of the respective axes. The servo motors 61 to 64 have a built-in pulse coder for position detection, and the position signal is fed back from this pulse coder as a pulse train. In some cases, a linear scale is used as the position detector. Further, a speed signal can be generated by F / V (frequency / speed) conversion of this pulse train.
In the figure, the position signal feedback line and velocity feedback are omitted. Servo motor 61
Is for the X axis, the servo motor 62 is for the Y axis, the servo motor 63 is for the Z axis, and the servo motor 64 is for the C axis.

The spindle control circuit 71 receives a spindle rotation command, a spindle orientation command, and the like, and outputs a spindle speed signal to the spindle amplifier 72. The spindle amplifier 72 receives the spindle speed signal and rotates the spindle motor 73 at the commanded rotation speed. In addition, the spindle is positioned at a predetermined position according to the orientation command.

A position coder 82 is connected to the spindle motor 73 by a gear or a belt. Therefore, the position coder 82 rotates in synchronization with the spindle 73, outputs a feedback pulse, and the feedback pulse is read by the processor 11 via the interface 81. This feedback pulse is used to move the other shaft in synchronization with the spindle motor 73 and perform machining such as thread cutting.

Next, how to obtain the value of the override when the circular interpolation on the cylindrical surface is performed by such a numerical controller will be specifically described. First, the ratio of the actual speed of the tool center and the command speed of the program when the command speed is not overridden when the cutting point correction is performed is calculated.

FIG. 3 is a diagram showing the movement locus of the tool during circular interpolation. In this example, the inside of the arc 90 having the radius R is cut on the virtual plane (Cy-Z plane). At this time, the tool center position Q passes through the passage 91 after the tool diameter is corrected.

Here, the tool radius is V, and the angle between the vector 92 from the center coordinates of the arc 90 to the tool 1 and the Cy axis is the center angle θ. At this time, the cutting point correction amount 93 (ΔCy
θ) is

[0041]

## EQU00003 ## .DELTA.Cy.theta. = V.COS.theta ..... Can be expressed by the equation (3). At this time, the pulse distribution amount is determined so that the tool center position Q becomes the command speed F. Therefore, the actual speed F1 in the case where the command speed is not overridden, the cutting point correction amount ΔCy is added to the command speed F0.
It becomes a value obtained by adding the variation of θ. That is, the actual speed F1
It can be seen that varies depending on the central angle θ.

In this case, the speed ratio (F1 / F0) between the command speed F0 and the actual speed F1 can be expressed by the following equation.

[0043]

Equation 4] speed ratio (the inner offset) = ^{[{(2VR-V 2) /} (R-V) 2} × SIN 2 θ + 1 ] ^1/2 ... (4) FIG. 4 is the central angle theta and the actual It is a figure which shows the relationship with speed F1.
The horizontal axis is the central angle, and the vertical axis is the velocity. in this way,
In cutting inside the arc, the tool is always moving at a speed equal to or higher than the command speed F0.

Now, consider the case where the command speed is overridden. Since the speed after the overriding (hereinafter referred to as the conversion speed) F2 is multiplied by the speed ratio (F1 / F0), the result should be F0.

[0045]

## EQU5 ## It is necessary to satisfy F2 × (F1 / F0) = F0 (5). That is,

[0046]

## EQU6 ## F2 = F0 ² / F1 (6)

Therefore, in order to make the actual speed of the tool the same value as the command speed, the command speed F0 may be overridden by a reciprocal multiple of the speed ratio (F1 / F0). If this value is the conversion ratio, the conversion ratio (F0 / F1) is

[0048]

Is [Equation 7] conversion ratio (inside offset) = 1 / ^{[{(2VR-V 2) /} (R-V) 2} × SIN 2 θ + 1 ] ^1/2 ... (7). This conversion ratio is a value when cutting inside the arc. Then, similarly, the speed ratio when cutting outside the arc can be obtained,

[0049]

## EQU8 ## Speed ratio (outer offset) = [1-{(2VR + V ² ) / (R + V) ² } × SINθ ² ] ^1/2 ... (8) Therefore, the conversion ratio in this case is

[0050]

Equation 9 Conversion Ratio (outside offset) = 1 / - a ^{[1 {(2VR + V 2)} / (R + V) 2} × SINθ 2 ] ^1/2 ... (9).

That is, it is determined whether the interpolation command cuts the outside of the arc or the inside of the arc.
By multiplying the command speed by the above-mentioned conversion ratio override, the actual speed of the tool can be matched with the command speed. As a result, it becomes possible to perform a highly accurate cutting process.

Further, a clamp function can be added so that the actual speed obtained as described above does not exceed the specified speed set by the command speed and the parameter. This clamp function can be configured in the feed rate control means 120 shown in FIG.

FIG. 5 is a block diagram of a cylindrical interpolation system including a clamp function. In this example, the feed rate control means 12
The internal structure of 0a is shown. Feed rate control means 120
When the circular interpolation command is output to the conversion ratio calculation unit 121 in a, the data of the command speed F and the circular arc radius R is input from the decoding unit 102 (shown in FIG. 1). Further, from the tool radius correcting means 104 (shown in FIG. 1), the tool radius V,
Designation flag Fla for inside offset or outside offset
g is input. Also, the interpolation means 107 (shown in FIG. 1)
From, the data of the central angle θi-1 is input. The conversion ratio calculation unit 121 calculates the conversion ratio from these data.

The comparison unit 122 includes parameter storage means 1
A parameter indicating the maximum velocity in the Z-axis direction and the Cy-axis direction of the virtual plane is input from 30, and the decoding means 10
From 2, the data of the command speed F and the arc radius R is input.

The comparing section 122 first compares the maximum velocities of the respective axes and selects the one having the lower maximum velocity. The selected speed is set as the speed limit. Then, the speed limit is compared with the command speed. As a result of the comparison, if the speed limit is greater than or equal to, the command speed is output. If the commanded speed is higher, the speed limit is output.

The override unit 123 multiplies the speed output from the comparison unit 122 by the conversion ratio. The conversion speed αFi after overriding is calculated by the interpolation means 10
It is output for 7.

As described above, when the command speed is less than or equal to the speed limit, the command speed is overridden, but when the command speed exceeds the speed limit, the speed limit is overridden. Never exceeds.

Although the circular interpolation has been described in the above example, the same can be applied to involute interpolation or the like.

[0059]

As described above, according to the present invention, when the curve is interpolated on the cylindrical surface, the actual speed change amount of the tool caused by the correction of the cutting point is calculated, and Since the override is applied so as to cancel the actual speed change amount, the actual speed becomes a constant value. As a result, accurate and stable cutting can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a cylindrical interpolation method of the present invention.

FIG. 2 is a numerical controller for implementing the present invention (CN
It is a block diagram of hardware of C).

FIG. 3 is a diagram showing a movement trajectory of a tool during circular interpolation.

FIG. 4 is a diagram showing a relationship between a center angle and a tool center speed.

FIG. 5 is a block diagram of a cylindrical interpolation method including a clamp function.

FIG. 6 is a diagram showing an imaginary plane expressed by expanding a cylindrical surface.

FIG. 7 is a diagram showing a positional relationship between a tool and a workpiece in grooving when cutting is performed on an imaginary plane in the same manner as a plane coordinate system.

FIG. 8 is a diagram showing a positional relationship between a tool and a work after cutting point correction.

FIG. 9 is a diagram illustrating a feed rate during cutting point correction.

[Explanation of symbols]

 101 Machining program 102 Decoding means 103 Coordinate conversion means 104 Tool diameter correction means 105 Correction component calculation means at block start point 106 Block start point correction component interpolation means 107 Interpolation means 108 Pulse conversion means 109 Synchronization correction component calculation means 110 Synchronization correction component Interpolation means 120 Feed rate control means

Claims (6)

[Claims] 1. A cylindrical interpolation method for machining on a cylindrical surface, wherein a tool radius offset vector is calculated on a virtual plane composed of a cylindrical axis and an imaginary linear axis that develops the cylindrical surface to calculate the tool. Tool diameter correcting means for obtaining the center passage of the tool, and when the curve interpolation command is output, the actual speed change amount of the tool caused by the cutting point correction is calculated, and the actual speed change amount is canceled. In addition, the feed speed control means for outputting a conversion speed obtained by overriding the command speed, and the conversion speed, by interpolating the central path of the tool,
Interpolation means for outputting a first interpolation pulse for the virtual linear axis and a second interpolation pulse for the cylindrical axis; pulse conversion means for converting the first interpolation pulse into a third interpolation pulse for the rotation axis And a cutting point correcting unit that corrects the cutting point so that the cutting surface of the tool is perpendicular to the cylindrical surface. 2. The feed speed control means sets the smaller maximum speed in each axis of the virtual plane as a speed limit, and if the command speed is higher than the speed limit, the speed limit is overridden. The cylindrical interpolation method according to claim 1, wherein when the command speed is equal to or less than the speed limit, the command speed is overridden. 3. The cylindrical interpolation method according to claim 1, wherein the interpolation command of the curve is a circular interpolation command. 4. The cutting point correcting means calculates a correction component in the virtual linear axis direction of a tool contact vector from the tool radius offset vector, and a correction component calculating means for interpolating the correction component to obtain the rotation axis. Correction component interpolating means for outputting a first correction pulse and a second correction pulse in the axial direction perpendicular to the cylinder axis, the third interpolation pulse, and the first correction pulse for outputting the rotation axis The cylindrical interpolation system according to claim 1, wherein the adder is a pulse. 5. The correction component calculation means comprises a correction component calculation means at a block start point for obtaining a correction component of a tool contact vector between blocks, and a synchronous correction component calculation means for calculating a correction component at each interpolation time. 5. The cylindrical interpolation method according to claim 4, wherein. 6. The correction component interpolating means synchronizes the block start point correction component interpolating means for interpolating the correction component at the block starting point before the interpolation of the interpolating means with the synchronous correction component for each interpolation of the interpolating means. 5. The cylindrical interpolation method according to claim 4, further comprising: a synchronous correction component interpolating means for interpolating the same.