JP3210301B2 - Numerical control unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerical controller for controlling a machine tool, a robot, and the like.

[0002]

BACKGROUND ART FIG. 12, for example, JP 64-8101
FIG. 2 is a block diagram showing a conventional numerical control device disclosed in Japanese Unexamined Patent Publication No. 2 (Kokai) No. 2; In the figure, reference numeral 41 denotes a command tape on which a command is punched, and reference numeral 42 denotes a tape reader for reading the command tape 41. Reference numeral 43 denotes a pre-processing unit for performing pre-processing of the read data, reference numeral 44 denotes a central processing unit (hereinafter, referred to as a CPU) for executing the arithmetic processing of the numerical control, and reference numeral 45 denotes a memory accessed by the CPU 44. 46 is a pulse distributor that distributes interpolation data as command pulses for each axis of the tool, 47 is a servo control circuit that drives a servomotor based on the command pulses,
48 is the servo motor.

Next, the operation will be described. First, the tape reader 42 reads tool movement data from the command tape 41 on which the command position and command speed are punched. When the read data includes the G code of the interpolation command, the preprocessing unit 43 sets a spline curve based on the commanded point sequence. The CPU 44 calculates the amount of movement per unit time in the tangential direction of the set spline curve, and
The tool trajectory is calculated in accordance with a program for creating interpolation data stored in. The interpolation data created in this way is distributed by the pulse distributor 46 as command pulses for each axis of the tool, and the respective servo control circuits 47
Sent to The servo control circuit 47 controls the servomotor 48 according to the received command pulse, and moves the tool via a ball screw or the like by the rotation of the servomotor 48.

As described above, in the above numerical control device, first, a tangent vector is obtained, a parameter change amount for moving on a spline curve at a constant speed is calculated from the tangent vector, and according to the parameter change amount, The interpolation point on the spline curve is calculated for each pulse distribution cycle, and the spline curve is calculated based on the cubic spline curve. The parameter Δt of the spline curve for moving the spline curve at a constant speed is determined by the movement amount f for each pulse distribution and the tangent vector pt ′.
Was required from.

[0005] In addition, as a document which describes a technique related to such a conventional numerical control device, there is, for example, Japanese Patent Application Laid-Open No. 3-19963. The curve interpolating device disclosed in Japanese Patent Laid-Open Publication No. Hei 3-19963 interpolates a given arbitrary curve with a minute line segment so as to guarantee a desired allowable error. The curvature of the curve at the position is compared with the curvature of the curve near the current position by the search length, and the line segment length is determined from the result of the determination.

Also, "Computer Aided Design", Vol. 19, No. 9 (1
(September 987), pp. 485-498, entitled “Curve and Surface Constructions Useing Rational Bee Splines”
and surface constructions using rational B-spline
s), rationalized B-splines (Non Unifo
The rm Rational B-Spline (NURBS) curve is becoming widely used in computer aided design (CAD).

[0007]

Since the conventional numerical control device is constructed as described above, it is an interpolation system that moves on a spline curve at a constant speed, and the interpolation method moves in the traveling direction (tangential direction of the spline curve). Therefore, smooth acceleration / deceleration control that does not cause vibration of the machine is not considered,
Since smooth acceleration control at the start point and deceleration control at the end point are not performed, smooth mechanical control on the spline curve cannot be performed. Further, since the parameter Δt of the spline curve for moving on the spline curve at a constant command speed is obtained from the tangent vector pt ′, not only the calculation time is increased, but also the spline curve of the spline curve obtained for moving at the constant speed command is obtained. Although the parameter Δt is obtained from the tangent vector pt ′, the tangent vector pt ′ cannot accurately obtain the ratio between the movement amount per one pulse distribution cycle and the parameter change amount of the spline curve, and the parameter Δt is used when the curvature is large. Causes a calculation error of the parameter Δt, and cannot move accurately on the spline curve at the command speed. In addition, it is not easy to obtain a tangent vector when performing interpolation of a spline curve. Even when a locus composed of a plurality of spline curves is interpolated, the machine may vibrate in a traveling direction (tangential direction of the spline curve). The problem is that smooth acceleration / deceleration control that does not cause a problem is not considered, and smooth acceleration control at the start point and deceleration control at the end point are not performed, so that mechanical control on the spline curve cannot be performed smoothly. was there.

In the conventional interpolation method, if the search length is set too small, the allowable error is sufficiently guaranteed, but the line segment becomes too small, and the subsequent processing in the linear interpolation part cannot follow up. If interpolation becomes impossible and the search length is set too large, an allowable error cannot be guaranteed, and the setting of the search length becomes troublesome. NU
When the RBS curve is interpolated by the above-described method, there is a problem that it takes a long calculation time to perform high-speed interpolation control .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has an acceleration control at a start point and a control at an end point.
Speed control considering acceleration / deceleration control such as deceleration control of
It can be driven smoothly on the spline curve,
The spline curve pattern corresponding to the command speed can be calculated using a simple calculation method.
Parameter calculation method, and also for command speed
Method to accurately calculate the parameters of the spline curve
Even if the trajectory is composed of multiple spline curves,
Drive smoothly on spline curve considering deceleration control
And the spline curves are connected smoothly.
If there is no speed control such as deceleration control or stop at the connection point
It is an object of the present invention to obtain a numerical control device capable of performing control.

[0010]

A numerical controller according to the present invention displays a command trajectory by displaying a curve corresponding to a desired movement trajectory.
A command input section for inputting in the form of a spline function to be expressed,
The current finger on the spline curve output from the command input
Approximate curve length from command position to end point of spline curve
Calculates the approximate distance given as a value and outputs the end point distance
The calculation unit and the proximity to the end point output from the end point distance calculation unit
A speed command that creates and outputs a feed speed command according to the similar distance
Output section and the speed command output from the speed command output section.
Acceleration / deceleration control unit that controls deceleration and outputs smooth speed commands
And the speed corresponding to the speed command output from the acceleration / deceleration control unit.
The spline is calculated using the parameter change of the
Parameter calculator that calculates and outputs curve parameters
And the spline curve output from the parameter calculator
Next command on spline curve using parameters
And a spline curve position calculator for calculating the position .

[0011] The numerical controller according to the present invention has a parameter
The parameter change amount of the data calculation unit by at least one processing cycle.
The previous parameter change and the finger at least one processing cycle earlier
Calculate using the ratio to the travel distance calculated from the command position.
It is something that has been done.

The numerical controller according to the present invention provides a command locus.
Is a spline that represents a curve corresponding to the desired trajectory
Command input section input in the form of a function and output from the command input section
From the current command position on the spline curve
Given as an approximation of the length of the curve to the end of the
An end-point distance calculator that calculates and outputs an approximate distance
Sends according to the approximate distance to the end point output from the separation calculation unit.
Command output section and speed command to create and output speed command
Acceleration / deceleration control of the speed command output from the output unit
Acceleration / deceleration control unit that outputs speed command and acceleration / deceleration control unit
Spline curve parameters corresponding to the output speed command
Calculate spline curve parameters using data change
Parameter calculation unit to calculate and output
Using the parameters of the spline curve output from
A spur that calculates the next command position on the pline curve
Speed output from the in-curve position calculator and acceleration / deceleration controller
And the distance corresponding to at least one processing cycle
Compare the travel distance calculated from the commanded position on the
Parameter correction to correct the parameter change amount
And a unit.

The numerical controller according to the present invention provides a command locus.
Represent multiple curves corresponding to the desired trajectory
Command input part to input in the form of
Of the plurality of spline curves output from the command input unit.
A connection state determination unit that determines continuity at a continuation point, and a connection state
The spline curves before and after are connected continuously by the judgment unit.
The current finger on the spline curve
Curve length from command position to end of rear spline curve
Calculate and output the approximate distance given as an approximate value of
The point distance calculator and the end point output from the end point distance calculator
Speed finger that creates and outputs a speed command according to the approximate distance at
Command output section and the speed command output from the speed command output section.
Acceleration / deceleration control section that controls acceleration / deceleration and outputs smooth speed commands
And the speed corresponding to the speed command output from the acceleration / deceleration control unit.
The spline is calculated using the parameter change of the
Parameter calculator that calculates and outputs curve parameters
And the spline curve output from the parameter calculator
The next finger on the spline curve
And a spline curve position calculator for calculating the command position
It is like that.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a numerical control device according to Embodiment 1 of the present invention. In the figure, reference numeral 1 denotes a trajectory command P (t) (where t is a parameter defining a spline curve, abbreviated as a parameter hereinafter) and a feed speed command Vco.
Command input section for inputting m. Each command is input as one block or a plurality of blocks as required.
It is memorized. The trajectory command P (t) is input in the form of a spline curve.

Reference numeral 2 denotes a speed pattern generation unit including an end point distance calculation unit, a speed command output unit, and an acceleration / deceleration control unit, which will be described later. Reference numeral 3 denotes an end point of the spline curve from the current command position.
Approximate distance Le given as an approximate value of the curve length up to
The end point distance calculation unit 4 calculates the feed speed command Vcom so that the approximate distance Le to the end point calculated by the end point distance calculation unit 3 can be moved and stopped, and the speed input to the acceleration / deceleration control unit. The speed command output unit 5 that outputs the command Vout is the acceleration / deceleration control unit that performs acceleration / deceleration control so that the speed command Vout of the speed command output unit 4 changes smoothly. For this acceleration / deceleration control, for example, a trapezoidal acceleration / deceleration control method described in Japanese Patent Application Laid-Open No. 1-237806 or an exponential function acceleration / deceleration control method conventionally used may be used. Here, the trapezoidal acceleration / deceleration control method includes an acceleration Δ
By specifying F, acceleration / deceleration is performed at the command acceleration ΔF, and acceleration / deceleration control is performed until the command speed is reached. The integral value of the difference between the speed command Vout input to the acceleration / deceleration control unit 5 and the output speed command Vs is stored in the acceleration / deceleration control unit 5 as the following distance Ld. V
When out becomes 0, it operates so as to continue to output the speed command Vs until the integrated value of the output speed Vs of the acceleration / deceleration control unit 5 reaches the following distance Ld. The output speed V of the acceleration / deceleration control unit 5
s is output as a synthesized speed command of the feed speed of each axis of the servo system.

Reference numeral 6 denotes a parameter calculator for calculating a parameter for determining a position on the spline curve corresponding to the speed command Vs of the acceleration / deceleration controller 5, and 7 denotes a parameter from the parameter calculator 6 and the command input unit 1. Command position (xk, yk, zk) to servo control system from curve command from
Is a spline curve position calculation unit that calculates.

Next, the operation will be described. Here, FIG.
Is a flowchart showing the flow of the overall processing of the operation. The processing is executed at a constant processing cycle (sampling cycle) ΔTs. These processes are realized by a computer system including a CPU, a memory, an input / output (I / O) interface, and the like. Now, it is assumed that the spline curve P (t) (0 ≦ t ≦ 1) in FIG. 3 is given as a command locus. Ps is the starting point and the coordinates are (xs, ys, zs
), Pe is the end point and the coordinate values are (xe, ye, ze), P (k
-1) is the current command position (the position command output to the servo control system one processing cycle ago) and the coordinates are (x (k-1), y (k-1),
z (k-1)). It is assumed that the spline curve P (t) is expressed in, for example, a B-spline curve format shown in the following equation (1).

[0018]

(Equation 1)

[0019] Here, BS i, _{n (t)} is a B-spline function, d _i is the control point of the three-dimensional space. When the parameter t is determined, the position coordinates on the spline curve are determined from the equation (1). By the way, when the parameter t = 0, P
When s point and t = 1, it is Pe point.

In FIG. 2, in step ST1, it is determined whether or not a trajectory command is read for one block. If the trajectory command has not been read, step ST
2, a trajectory command block expressed in the form of a B-spline curve as in equation (1) and a feed speed command in this block are read. Next, step ST3 in the current command position P (k-1) (x (k-1), y (k-1), z (k-1)) Crow
Given as an approximation to the length of the curve up to the end of the curve
The approximate distance to the end point Pe is calculated. At this time,
For the parameter t relating to the plumb curve, t = t
(K-1). The approximate distance Le from the current command position P (k-1) to the end point Pe is calculated using, for example, the following equation (2).

[0021]

(Equation 2)

Thereafter, in steps ST4 to ST6, the speed command output unit 4 outputs the approximate distance Le to the end point and the following distance Ld (k-1) one processing cycle before the following distance Ld.
From the feed speed command Vcom, the speed command Vcom is controlled so as to stop accurately at the end point, and the speed command Vout is output. The speed command Vout is determined under the conditions shown by the following equations (3) to (5).

<Condition 1> If Le−Ld (k−1) ≧ Vcom * ΔTs, Vout = Vcom (3) <Condition 2> 0 <Le−Ld (k−1) <Vcom * If ΔTs, Vout = (Le−Ld (k−1) / ΔTs... (4) <Condition 3> If 0 ≧ Le−Ld (k−1), Vout = 0. ... (5)

That is, in step ST4, the conditions 1 to 3 are determined. Except for condition 1, all deceleration operations are performed. If the condition 1 is satisfied, an operation of YES is performed, and if not, an operation of NO is performed. In step ST5, Vout is calculated as in equation (3).
To determine. In step ST6, the speed command Vout is determined according to the conditions 2 and 3 as shown in the equations (4) and (5). Next, in step ST7, the speed command Vout is subjected to acceleration / deceleration control, and the speed command Vs is calculated and output. As the acceleration / deceleration method, for example, the trapezoidal acceleration / deceleration method described above is used. The following distance L
d is modified by the following equation (6) and used in the next processing cycle.

Ld = Ld (k−1) + (Vout−Vs) * ΔTs (6)

Next, in step ST8, the parameter change amount Δt ′ when the current command position P (k−1) on the spline curve P (t) is changed by the minute parameter Δt ′.
And the ratio α of the moving distance ΔP ′. Spline curve P
The coordinates of the current position P (k-1) on (t) are (x (k-1)
, Y (k-1), z (k-1)) and the parameter is t (k-1)
The position P (t (k−1) + Δt ′) at t (k−1) + Δt ′, which has changed by a small parameter Δt ′, can be calculated using the above-described equation (1), and the coordinate value at that time is (x ( k-1) ', y (k
-1) ', z (k-1)'). The ratio α is obtained by the following equation (7).

Α = Δt ′ / ΔP ′ (7)

However, in the above equation (7), the moving distance Δ
P ′ is given by the following equation (8).

[0029]

(Equation 3)

The parameter change amount Δt ′ is set to a value that satisfies the following equation (9).

[0031]

(Equation 4)

Next, in step ST9, the parameter change amount Δtk corresponding to the speed command Vs is calculated by the following equation (1).
0).

Δtk = α · Vs * ΔTs (10)

Next, in step ST10, the spline curve P (t) is calculated using the estimated parameter variation Δtk.
The upper position P (t (k-1) +. DELTA.tk) is calculated using equation (1). The coordinate calculation value of P (t (k-1) + Δtk) is output to the servo control system as a command position. Then step ST
At 11, the coordinates of the position P (t (k-1) +. DELTA.tk) are calculated as x (k-1) = xk, y (k-1) = yk and z (k-
1) As = zk, these are stored as the current command positions in the next processing cycle.

When the curvature of the spline curve is small, the same effect can be obtained by obtaining α from the tangent vector.

Embodiment 2 Next, a second embodiment of the present invention will be described with reference to the drawings.
FIG. 4 is a block diagram showing a numerical control device according to Embodiment 2 of the present invention. In the figure, 1 to 5 and 7 have the same configurations as those of the first embodiment, and therefore the description thereof is omitted. Reference numeral 8 denotes a movement amount calculation unit for calculating the movement amount ΔP (k-1) of the command position during one processing cycle obtained from the command position one processing cycle ago and the command position two processing cycles ago.
Reference numeral 9 denotes a parameter change amount and a movement amount based on the movement amount ΔP (k-1) of the commanded position and the parameter change amount Δt (k-1) (the parameter change amount Δtk before one processing period) output one processing cycle ago. 1 in that the parameter tk is calculated from the speed command Vs of the acceleration / deceleration control unit 5, the ratio α, and the parameter t (k-1) one processing cycle earlier. This is a parameter calculator different from that of the first embodiment.

Next, the operation will be described. Here, FIG.
Is a flowchart showing the flow of the operation, in step S
Since T1 to ST7 and steps ST8 to ST11 perform the same processing as that of FIG. 2, their description is omitted. At step ST20, the command position (x (k-1), y (k-1), z (k-1)) to the servo system in the previous processing cycle and the command position (x (k-2),
y (k-2), z (k-2)), the moving amount ΔP (k-1) is obtained by the following equation (11).

[0038]

(Equation 5)

Next, in step ST21, the parameter calculator 9 calculates the parameter change amount Δ
t (k-1) and the movement amount ΔP (k-1) of the command position during one processing cycle
Then, the ratio α between the parameter change amount and the movement amount is calculated by the following equation (12).

Α = Δt (k−1) / ΔP (k−1) (12)

In this method, the ratio α between the parameter change amount and the movement amount at the start point of the spline curve cannot be obtained because the parameter change amounts Δt (k−1) and ΔP (k−1) do not exist. Therefore, in order to obtain the ratio α at the starting point, as shown in equation (7) of the first embodiment, the amount of movement ΔP ′ when the minute parameter Δt ′ is changed is obtained, and the ratio α
Is used.

In the second embodiment, the ratio α between the parameter change amount and the movement amount is calculated using the parameter change amount Δt (k−1) and the movement amount ΔP (k−1) one processing cycle ago. However, the calculation may be performed using the parameter change amount and the movement amount several processing cycles before.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to the drawings.
FIG. 6 is a block diagram showing a numerical control device according to Embodiment 3 of the present invention. In the figure, 1 to 7 have the same configurations as those of the first embodiment, and therefore the description thereof is omitted. Numeral 10 determines whether the parameters obtained by the parameter calculator 6 are valid, and if not, corrects the parameters, and corrects the position command to the servo control system obtained by the spline curve position calculator 7. This is a parameter correction unit.

Next, the operation will be described. Here, FIG.
Is a flowchart showing the flow of the operation, in step S
In T1 to ST9 and ST11, the same processing as that in FIG. 2 is performed, and the description thereof is omitted. In step ST30, similarly to step ST10 in FIG. 2, the position P (t (k-1) + Δtk) on the spline curve is calculated using equation (1) using the parameter change amount Δtk obtained in step ST9. The coordinate values (xk, yk, zk) are obtained. Next, in step ST31, the acceleration / deceleration control unit 5
Amount V during one processing cycle of command speed Vs output from
s * ΔTs, the command positions (x (k−1), y (k−1), z (k−1)) calculated in the previous processing cycle and the command positions (xk, yk, zk) and the difference β from the movement amount ΔPk of the command position during one processing cycle is determined by the following equation (13).

Β = Vs * ΔTs−ΔPk (13)

Here, the difference β of the movement amount is a value corresponding to the speed error, and is caused by a calculation error of the parameter change amount Δtk. The movement amount ΔPk is obtained by the following equation (14).

[0047]

(Equation 6)

Next, at step ST32, the difference β
Is determined to be less than or equal to the allowable value. If difference β is equal to or smaller than the allowable value, the process proceeds to step ST34; otherwise, the process proceeds to step ST33. The allowable value is a value determined from the maximum acceleration and the like that can be allowed by the servo control system. In step ST34, the command position (xk, yk, zk) obtained in step ST31 is output as a position command for the servo system. On the other hand, in step ST34, the parameter change amount Δtk is corrected. For example, the following equation (1
Correct using 5).

Δtk = (Vs * ΔTs / ΔPk) * Δtk (15)

The parameter variation Δtk corrected here
, The position on the spline curve is calculated again in step ST30, and the parameter change amount Δtk, that is, the difference β
Are repeated until the value becomes equal to or less than the specified value.

When the parameter correction method according to the present embodiment is used in combination with the parameter calculation method according to the second embodiment, a parameter corresponding to a speed command can be easily and accurately obtained.

Embodiment 4 FIG. Next, a fourth embodiment of the present invention will be described with reference to the drawings.
FIG. 8 is a block diagram showing a numerical controller according to Embodiment 4 of the present invention. In the figure, 1 to 5 and 7 are the same as those of the first embodiment, and the description thereof is omitted. Reference numeral 11 denotes a parameter conversion unit different from that of the first embodiment, which is denoted by reference numeral 6 in FIG. 1 in that a determination as to whether or not to reduce the speed command is output to a connection state determination unit described later. 12 is given by a trajectory command with a plurality of spline curves.
If they are, it is determined whether or not the connection state between each spline is connected to a continuous, if it is determined that the connection state is continuous, the connection state determining unit for changing the position of the end point of the spline curve is there. Note that this connection state determination unit 1
The determination as to whether or not the connection state according to 2 is continuous can be made based on, for example, the direction and length of the tangent vector at the connection point. When the trajectory command is represented by a B-spline curve, it can be determined from the positional relationship between the control points representing the B-spline curve near the connection point.

Next, the operation will be described. Here, FIG.
Is a flowchart showing the flow of the operation, in step S
In T1 to ST11, processes equivalent to those in FIG. 2 of the first embodiment are performed, and therefore description thereof is omitted. now,
As shown in FIGS. 10 and 11, it is assumed that the trajectory command is represented by two B-spline curves P1 (t) and P2 (t). P1s
Is the start point of P1 (t), P1e (t) is the end point of P1 (t), and P2s is P
The start point of 2 (t), P2e is the end point of P2 (t), and P1e and P2s
Are consistent. The trajectory command shown in FIGS. 10 and 11 is started from P1s and moves at the speed command Vcom.
Stop at The points Pa and Pb are command positions on P1 (t), Pa is the case where the distance to the end point P1e of the spline curve P1 (t) is sufficient for deceleration control, and Pb is the spline curve P1. This is the case where the distance to the end point P1e in (t) is not sufficient for deceleration control.

For example, if the current command position is Pa, in step ST3, the current command position is shifted from Pa to P1e.
The approximate distance given as an approximate value of the curve length up to is calculated, and it is determined in step ST4 that the deceleration operation is not necessary,
The process flows to step ST5. However, when the current command position has reached a position such as Pb, if it is determined in step ST4 that a deceleration operation is necessary, the process proceeds to step S4.
Proceeding to T40, it is determined whether there is a next trajectory command. If there is no next trajectory command, step S
At T6, if there is, the process moves to step ST41. In step ST41, the next trajectory command (FIG. 10,
In FIG. 11, the connection state determination unit 12 determines whether or not P2 (t)) is continuously connected to the currently moving trajectory command (P1 (t) in FIGS. 10 and 11). If it is determined that the connection is continuous as shown in FIG. 10, step ST4
If it is determined that the connection is not continuous in the process of FIG. 11 as shown in FIG. 11, the process of step ST6 is performed so as to decelerate and stop at the end point P1e of P1 (t). In step ST42, since the connection points are continuous, the end point is set to the next locus command P2.
As the end point P2e of (t), the current finger is
From the command position Pb to the end point P2e of the spline curve
The approximate distance Le given as an approximate value of the curve length is calculated again by the following equation (16), and the process proceeds to step ST4.

[0055]

(Equation 7)

However, the coordinates of the current command position Pb are (xb, yb, zb), and the coordinates of P2e are (x2e, y2e,
z2e).

As described above, the connection state of the trajectory command of the spline curve is determined, the position of the end point is changed, and speed control is performed. Therefore, even when the trajectory command is expressed by a plurality of spline curves, smooth interpolation control is performed. It can be performed.

[0058]

As described above, according to the present invention, the command
Current command position on spline curve given as trajectory
Of the curve length from the position to the end of the spline curve
Calculated from the speed command based on the approximate distance given as
The next command position on the spline curve from the parameters
Calculation and realize smooth movement
It is configured to output the speed command with acceleration / deceleration control.
To perform spline curve interpolation while performing acceleration / deceleration control.
And increase the speed and accuracy of machining.
An effect that can mow be.

According to the present invention, the parameter calculation unit
The parameter change should be at least one parameter before the processing cycle.
From the data change amount and the command position at least one processing cycle earlier.
It is configured to calculate using the ratio with the calculated movement amount
So the calculation time of the parameters of the spline curve can be reduced
That the cost reduction of the numerical controller can be expected
To play.

According to the present invention, the output from the acceleration / deceleration control unit
And the distance corresponding to the speed command
Movement calculated from the command position on the previous spline curve
Parameter to correct the parameter change amount by comparing the
Data correction section so that accurate speed control
Control, speeding up machine work,
It has the effect of being able to measure the degree.

According to the present invention, a plurality of spline curves
Even if the command trajectory is given by
A connection state determination unit that determines continuity at connection points is provided,
The spline curves before and after are continuously connected by the connection status judgment unit.
If it is determined that the current
Song from the current command position to the end of the rear spline curve
Calculate the approximate distance given as an approximation of the line length
The complex configuration with multiple spline curves
Machine tools can be controlled smoothly even on trajectories.
Speed and precision of machine work.
This has the effect.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a numerical control device according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of an operation of the embodiment.

FIG. 3 is an explanatory diagram showing an example of a spline curve in the embodiment.

FIG. 4 is a block diagram showing a numerical control device according to a second embodiment of the present invention.

FIG. 5 is a flowchart showing a flow of the operation of the embodiment.

FIG. 6 is a block diagram showing a numerical control device according to a third embodiment of the present invention.

FIG. 7 is a flowchart showing a flow of the operation of the embodiment.

FIG. 8 is a block diagram showing a numerical controller according to Embodiment 4 of the present invention.

FIG. 9 is a flowchart showing a flow of the operation of the embodiment.

FIG. 10 is an explanatory diagram showing an example of a spline curve in the embodiment.

FIG. 11 is an explanatory diagram showing another example of a spline curve in the embodiment.

FIG. 12 is a block diagram showing a conventional numerical control device.

[Description of Signs] 1 Command input unit, 2 Speed pattern generation unit, 3 End point distance
Separation calculation unit, 4 speed command output unit, 5 acceleration / deceleration control unit, 6
Parameter calculator, 7 spline curve position calculator,
8 Movement amount calculation unit, 9 Parameter calculation unit, 10 parameters
Meter correction unit, 11 parameter conversion unit, 12 connection
Condition judgment part.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G05B 19/4103

Claims (4)

(57) [Claims] (1)Command trajectory corresponds to desired movement trajectory
Command input in the form of a spline function expressing a curve
Power and On the spline curve output from the command input unit
Song from the current command position to the end point of the spline curve
Calculate and output approximation distance given as approximation of line length
An end point distance calculation unit, Approximation to the end point output from the end point distance calculation unit
Speed command output that creates and outputs a feed speed command according to the distance
Power and The speed command output from the speed command output unit is controlled by acceleration / deceleration.
An acceleration / deceleration control unit that outputs a smooth speed command, Before corresponding to the speed command output from the acceleration / deceleration control unit
Using the parameter change amount of the spline curve,
Parameters for calculating and outputting parameters of the pline curve
A calculation unit, The spline tune output from the parameter calculation unit
Using the parameters of the line on the spline curve
A spline curve position calculator that calculates the next command position
Numerical control unit equipped. 2. A parameter change of the parameter calculator.
The amount is a parameter change amount at least one processing cycle before, and
Movement calculated from the command position at least one processing cycle before
The numerical control device according to claim 1, wherein the numerical control is performed using a ratio with the amount.
Place. (3)Command trajectory corresponds to desired movement trajectory
Command input in the form of a spline function expressing a curve
Power and On the spline curve output from the command input unit
Song from the current command position to the end point of the spline curve
Calculate and output approximation distance given as approximation of line length
An end point distance calculation unit, Approximation to the end point output from the end point distance calculation unit
Speed command output that creates and outputs a feed speed command according to the distance
Power and The speed command output from the speed command output unit is controlled by acceleration / deceleration.
Smooth speed command Acceleration / deceleration control unit that outputs Before corresponding to the speed command output from the acceleration / deceleration control unit
Using the parameter change amount of the spline curve,
Parameters for calculating and outputting parameters of the pline curve
A calculation unit, The spline tune output from the parameter calculation unit
Using the parameters of the line, place
Spline curve position calculator for calculating the next command position
When, The distance corresponding to the speed command output from the acceleration / deceleration control unit
Release and the finger on the spline curve at least one processing cycle earlier
The travel distance calculated from the command position,
Number with parameter correction unit that corrects data change amount
Value control device. (4)Command trajectory corresponds to desired movement trajectory
In the form of a spline function that represents each of multiple curves
A command input unit for inputting, The plurality of spline songs output from the command input unit
A connection state determination unit that determines continuity at a connection point of the line, The spline curves before and after the connection state determination unit are linked.
If it is determined that the spline is connected,
The spline curve at the rear from the current command position on the curve
Approximate distance given as an approximation of the length of the curve to the end point of
An end-point distance calculator for calculating and outputting the separation; Approximation to the end point output from the end point distance calculation unit
Speed command output unit that creates and outputs speed commands according to the distance
When, The speed command output from the speed command output unit is controlled by acceleration / deceleration.
An acceleration / deceleration control unit that outputs a smooth speed command, Before corresponding to the speed command output from the acceleration / deceleration control unit
Using the parameter change amount of the spline curve,
Parameters for calculating and outputting parameters of the pline curve
A calculation unit, The spline tune output from the parameter calculation unit
Using the parameters of the line, place
A spline curve position calculator for calculating the next command position
Numerical control unit equipped with