JPH10240328A - Numerical controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly machine the surface of a work by a machine tool and to effectively prevent the damage or the like of the machine tool by unnecessary acceleration by calculating the correction amount of a point sequence command so as to make the one of a large value in plural curvature evacuated values be small in a correction amount calculation part. SOLUTION: The correction amount calculation part 5 calculates the correction amount of the point sequence command so as to make the curvature evacuated value of a track by the point sequence command set by an evaluation range setting part 4 be small. A correction amount limiting part 6 limits the correction amount of the point sequence command so as not to make the correction amount of the points sequence command exceed a maximum allowable error. A point sequence movement part 7 moves the position of the point sequence command of a point sequence command input part 3 corresponding to output from the correction amount limiting part 6. A point sequence interpolation part 8 performs interpolation calculation based on the point sequence command outputted from the point sequence movement part 7 and a speed command, calculates the positions command of the respective shafts of the machine tool 2 and outputs it for each sampling cycle. A servo control part 9 controls the machine tool 2 based on a position command or the like outputted by the point sequence interpolation part 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerical controller used for numerical control of a machine tool, and more particularly to a numerical controller having a function of smoothly correcting a point sequence command for position control of a machine tool. It is about.

[0002]

2. Description of the Related Art Normally, an NC program of an NC apparatus for controlling a machine tool, when a locus such as a smooth spline curve, expresses the curve as a series of minute line segments by linear approximation. In this case, the NC program of the NC device is represented as a continuous point sequence (position coordinate points) or as a continuous line segment. Such a locus based on the linear approximation is generally referred to as a point sequence command.

When the point sequence command is created by a CAD / CAM device, discontinuous points may occur due to calculation errors or the like. Further, when the point sequence command is created by measuring the shape of the model, a discontinuous trajectory may be rattled due to a measurement error generated when the model is copied and measured. If the point sequence command has a discontinuous trajectory, there is a problem that the machined surface is not smooth, and unnecessary acceleration may be applied to the machine tool to damage the machine.

As a method of correcting such a discontinuous point of the point sequence command, there is a method disclosed in, for example, Japanese Patent Application Laid-Open No. 3-63708. In this method, in order to correct the discontinuous point sequence command, an approximate point of the center of gravity of the triangle is calculated for every three consecutive point sequence commands, and the point sequence command is moved to the approximate point of the center of gravity. It is carried out.

[0005]

Since the conventional numerical controller is constructed as described above, the correction is performed by obtaining the center of gravity of the triangle from the correction point in the continuous point sequence command and a total of three points before and after the correction point. Therefore, the point sequence information used for correcting the point sequence command is small, and therefore, there is a problem that the correction does not necessarily perform an effective correction for smoothing the entire point sequence command.

If the point sequence command expresses a locus such as a circular arc with a small change in curvature, if the point sequence command is modified by the above-described conventional method, the curvature is corrected to a point sequence command having a large curvature. There is a problem that the smoothness is lost and the correction may be performed, resulting in a point sequence locus having a large error.

Further, since there is no limitation on the correction amount of the point sequence command, there is a problem that a processing error may be larger than an allowable range, and a processing defect may occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and it is possible to perform an effective correction for smoothing the entire point sequence command using a large amount of point sequence information by a simple calculation method. Accordingly, an object of the present invention is to provide a numerical control device capable of smoothing a machined surface of a machine tool and effectively preventing damage to the machine tool due to unnecessary acceleration of the machine tool.

Further, according to the present invention, even in the case of a point sequence command expressing a smooth trajectory such as an arc, a smooth point sequence command can be obtained without deteriorating the trajectory as in the conventional method. It is an object of the present invention to obtain a numerical control device capable of performing such operations.

Further, the present invention provides a numerical control device capable of preventing a situation in which a correction amount of a point sequence command becomes a large value exceeding an allowable error and a machining failure by the machine tool or damage to the machine tool occurs. The purpose is to:

Further, according to the present invention, a smooth point sequence command can be obtained without deteriorating the locus even for a point sequence command in which a change in curvature or a change in the interval between the point sequence commands is large. It is an object of the present invention to obtain a numerical control device that can effectively correct the above.

Further, the present invention provides a numerical controller capable of accurately restoring an original trajectory even for a trajectory in which the types of curves and the presence or absence of an error are combined in a complicated manner. Aim.

[0013]

According to a first aspect of the present invention, there is provided a numerical control apparatus, wherein the correction amount calculating section calculates a curvature evaluation value corresponding to a curvature of a curve passing a point sequence command at a plurality of points within an evaluation range. In addition, the correction amount of the point sequence command is calculated so as to reduce a larger one of the plurality of curvature evaluation values.

According to a second aspect of the present invention, in the numerical control apparatus, the correction amount calculating section includes, as a curvature evaluation value, a difference vector indicating a first-order or higher-order change amount of a line vector connecting continuous point sequence commands. Is used.

According to a third aspect of the present invention, in the numerical control apparatus, the correction amount calculation unit calculates the correction amount of each axis component such that the sum of squares of each axis component of the difference vector at a plurality of locations is minimized. This is to calculate.

According to a fourth aspect of the present invention, there is provided a numerical controller including a correction amount limiting unit for limiting the correction amount in the correction amount calculation unit to a value equal to or less than an allowable error value.

According to a fifth aspect of the present invention, in the numerical control device, the correction amount calculating unit calculates the difference vector calculated using the line vector weighted by the amount related to the length of the line vector as the difference vector. It is intended to be used.

According to a sixth aspect of the present invention, in the numerical controller, the correction amount calculating section applies a second-order or higher-order curve to the point sequence command within the evaluation range, and corrects the point sequence command so as to approach the curve. The amount is calculated.

According to a seventh aspect of the present invention, in the numerical control device, the correction amount calculating section applies a quadratic curve to a point sequence command within the evaluation range.

The numerical controller according to the invention of claim 8 is provided with a correction amount limiting unit for limiting the correction amount in the correction amount calculation unit to a value equal to or less than an allowable error value.

According to a ninth aspect of the present invention, in the numerical control device, the correction amount calculation unit uses the corrected point sequence command for calculating a correction amount for a subsequent correction point.

According to a tenth aspect of the present invention, there is provided a numerical controller including a trajectory judging unit for judging a property of a trajectory based on the input point sequence command, and setting an evaluation range according to the determined property of the trajectory. The evaluation range set in the section and / or the correction amount calculation method in the correction amount calculation section are appropriately changed.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a block diagram showing a configuration of a numerical controller according to Embodiment 1 of the present invention. In the drawing, reference numeral 1 denotes a numerical controller according to Embodiment 1 of the present invention;
Reference numeral 2 denotes a machine tool having a three-axis configuration of x, y, and z axes. Reference numeral 3 denotes a point sequence command input unit that inputs and stores an NC program including a point sequence command from a CAD / CAM device or the like. Is instructed by a sequence of points representing position coordinates or a sequence of line segments connecting the sequence of points. Reference numeral 4 denotes an evaluation range setting unit for selecting several point sequence commands input from the point sequence command input unit 3 to set an evaluation range, and 5 denotes a curvature of a locus according to the point sequence command set by the evaluation range setting unit 4. A correction amount calculation unit for calculating the correction amount of the point sequence command so as to reduce the evaluation value, a correction for limiting the correction amount of the point sequence command so that the correction amount of the point sequence command does not exceed a maximum allowable error. It is a quantity limiting unit. This maximum allowable error is set in advance in accordance with the processing accuracy. 7
Is a point sequence moving unit for moving the position of the point sequence command of the point sequence command input unit 3 in accordance with the output from the correction amount limiting unit 6, and 8 is a point sequence command output from the point sequence moving unit 7 and an NC program. A point-sequence interpolation unit that performs an interpolation calculation based on the speed command specified in (1), calculates a position command for each axis (x, y, z-axis) of the machine tool 2 and outputs the position command at each sampling cycle. The servo control unit controls the machine tool 2 based on a position command or the like output from the unit 8.

In the machine tool 2, reference numeral 10 denotes a motor for driving the machine tool 2, and reference numeral 11 denotes an encoder for measuring the position and speed of the machine tool 2. The servo control unit 9
Control calculations such as position control and speed control are performed based on the output of the point sequence interpolation unit 8 and the measured values of the encoder 11 of the machine tool 2, and power is supplied to the motor 10 of the machine tool 2.

Reference numeral 12 denotes a point sequence command correction unit of the numerical controller 1 according to the first embodiment. The point sequence command input unit 3, the evaluation range setting unit 4, the correction amount calculation unit 5, the correction amount restriction unit 6, and the A column moving unit 7 is provided. The numerical control device 1 is realized by a computer system including one or a plurality of CPUs (central processing units), a memory, an input / output interface, and the like.

FIG. 2 is a schematic diagram showing an example of a point sequence command. The point sequence command P _i has three-dimensional position coordinates (Px _i , Py _i ,
Pz _i ) (where i is the index of the point sequence command, i = 1, 2,..., N, P ₁ is the starting point, P _n
Is the end point. ).

Next, the operation will be described. First, the operation of the point sequence command correction unit 12 of the numerical controller 1 will be described with reference to FIG. FIG. 3 is a flowchart showing the operation of the point sequence command correction unit 12 of the numerical controller 1 according to Embodiment 1 of the present invention. The evaluation range setting unit 4 shown in FIG.
Set a point as the evaluation range.

Step ST1 is a process of the point sequence command input unit 3, which reads an NC program from a CAD / CAM device or the like, and outputs the point sequence commands P ₁ , P ₂ ,.
, _Pn are stored in the memory.

Steps ST2 to ST8 are processing of the evaluation range setting section 4. The evaluation range setting unit 4 sets five consecutive points as an evaluation range. That is, when the point of correcting 2 and P _i, the correction point P _i and the two points before and after the _{P i-2, P i-} 1, P i + 1, P i + 2 selected Is done.

In step ST2, the point sequence command P _i
As a first modification point, the index i is 2, i.e. P ₂ is set. In step ST3, if i = 2, the process proceeds to step ST4, and if not i = 2, the process proceeds to step ST5. In step ST5, i = n
If −1, the process proceeds to step ST6, and if not i = n−1, the process proceeds to step ST7. Step ST7
Then, if i = n ( _Pn, that is, the end point), step ST2
Otherwise, the process proceeds to step ST8.

In steps ST4, ST6, and ST8, the correction point P _i and two points before and after the correction point P _i (P _{i− 2} , P _i−1 ,
(P _{i + 1} , P _{i + 2} ) is selected, but in the step ST4
Is a process at the start point of the point sequence command, step ST6 is a process at the end point of the point sequence command, and step ST8 is a process other than the start point and the end point.

Since there is no point P _i-2 in step ST4 and no point P _{i + 2} in step ST6, equation (101) is used in step ST4, and equation (102) is used in step ST6. And extrapolate the point sequence command. _{P i-2 = 2P 0 -P} 1 (101) P i + 2 = 2P n -P n-1 (102)

Step ST9 is a process of the correction amount calculating section 5, and includes steps ST4, ST6, and ST8.
Calculating a correction amount E _i of the point P _i in the selected the five points. The correction amount E _i is the correction amount of the i-th point P _i , and X, Y,
This is a vector including the Z-axis correction amount (ex _i , ey _i , ez _i ).

A method of calculating the correction amount E _i of P _{i by} the point sequence command shown in FIG. 2 will be described below. FIG. 4 is an explanatory diagram of the correction operation of the point sequence command. First, as shown in FIG. 4, from the point sequence command of FIG.
_i−2 , S _i−1 , S _i , S _{i + 1} are calculated. S _i−2 = P _i−1 −P _i−2 = (Px _i−1 −Px _i−2 , Py _i−1 −Py _i−2 , Pz _i−1 −Pz _i−2 ) = (Sx _{i -2, Sy i-2, Sz} i-2) (103) S i-1 = P i -P i-1 = (Px i -Px i-1, Py i -Py i-1, Pz i -Pz _{i-1) = (Sx i} -1, Sy i-1, Sz i-1) (104) S i = P i + 1 -P i = (Px i + 1 -Px i, Py i + 1 -Py _{i, Pz i + 1 -Pz i} ) = (Sx i, Sy i, Sz i) (105) S i + 1 = P i + 2 -P i + 1 = (Px i + 2 -Px i + 1, Py _{i + 2} −Py _{i + 1} , Pz _{i + 2} −Pz _{i + 1} ) = (Sx _{i + 1} , Sy _{i + 1} , Sz _{i + 1} ) (106)

Next, as shown in FIG. 4, a first-order difference vector (difference vector) △ S _i−1 , △ S _i , △ S _{i + 1} is calculated. ΔS _i−1 = S _i−1 −S _i−2 = (Sx _i−1 −Sx _i−2 , Sy _i−1 −Sy _i−2 , Sz _i−1 −Sz _i−2 ) (107) _{△ S i = S i -S i} -1 = (Sx i -Sx i-1, Sy i -Sy i-1, Sz i -Sz i-1) (108) △ S i + 1 = S i + 1 _{-S i = (Sx i + 1} -Sx i, Sy i + 1 -Sy i, Sz i + 1 -Sz i) (109)

Since the point sequence commands P _{i-2 to} P _{i + 2 in} FIG. 4 are arranged at substantially equal intervals, the first-order difference vector △ S
_i−1 , △ S _i , △ S _{i + 1} are point sequence command trajectories P, respectively.
between _i-2 to P _i, between _{P i-1 ~P i + 1} , when the curvature between P _i ~P _i + ₂ is large is large, when the curvature is small, a small value. Therefore, the difference vector is used as a curvature evaluation value.

When the correction point P _i is moved by the correction amount E _i , the difference vectors in the equations (107), (108) and (109) are as shown in the following equations (110) to (112).
Here, the corrected difference vector is represented by △ S _i−1 ′, △ S
_i ′ and △ S _{i + 1} ′. ΔS _i−1 ′ = (S _i−1 + E _i ) −S _i−2 = P _i −2P _i−1 + P _i−2 + E _i (110) ΔS _i ′ = (S _i −E _i ) − (S _i-1 + E _i ) = P _{i + 1} −2P _i + P _i−1 −2E _i (111) ΔS _{i + 1} ′ = S _{i + 1} − (S _i −E _i ) = P _{i + 2} -2P _{i + 1} + P _i + E _i (112)

Here, equations (110), (111), and (11)
In order to reduce the difference vector having a large value in the difference vector of 2), 2 of each axis component of the difference vector is used.
The correction amount E _i (ex _i , ey _i , ez) that minimizes the sum of the powers
_i ) is calculated. First, a method of obtaining the x-axis component ex _i of the correction amount E _i will be described.

The sum J of the squares of the x-axis component of the difference vector J
x is given by the following equation (113). _{Jx = (Px i -2Px i-} 1 + Px i-2 + ex i) 2 _{+ (Px i + 1 -2Px i} + Px i-1 -2ex i) 2 _{+ (Px i + 2 -2Px i} + 1 + Px i + ex i) 2 (113)

[0040] Formula (113) is a quadratic expression of _{ex i, Jx / ex i =} 0 to determine the ex _i this is a minimum
Distant and rearranging the ex _i, ex _i = - a _{(Px i-2 -4Px i-} 1 + 6Px i -4Px i + 1 + Px i + 2) / 6 (114). When the y-axis and the z-axis are similarly calculated, the following equation is obtained. _{ey i = - (Py i-} 2 -4Py i-1 + 6Py i -4Py i + 1 + Py i + 2) / 6 (115) ez i = - (Pz i-2 -4Pz i-1 + 6Pz i -4Pz i ₊₁ + Pz _{i + 2} ) / 6 (116)

The above results (114), (115) and (11)
Expression 6) is expressed by the following equation.

In step ST9, equations (114) and (11)
5) and (116) are calculated, and the correction amount _Ei is obtained as described above.

Steps ST10 to ST21 are processes performed by the correction amount limiting unit 6. Step ST10
Then, the absolute value of the x-axis correction amount ex _i calculated by the equation (114) is calculated by using a preset maximum allowable amount emax.
If larger, the process proceeds to step ST11; if smaller, the process proceeds to step ST14.

In step ST11, if ex _i is negative, the process proceeds to step ST12; otherwise, the process proceeds to step ST13. In step ST12, ex _i = −emax. In step ST13, ex _i = emax, and the process proceeds to step ST14. Advance. Thereby, the correction amount e
The absolute value of x _i is limited to the maximum allowable amount emax or less.

In steps ST14 to ST17, processing for limiting the correction amount ey _i of the y-axis component to the maximum allowable amount emax or less is performed in the same manner as the processing of the x-axis component.

In steps ST18 to ST21, similarly to the processing of the x-axis component, the processing of limiting the correction amount ez _i of the z-axis component to the maximum allowable amount emax or less is performed.

In step ST22, the above-described step ST22 is executed.
The correction amount E _i for the point P _i calculated in 9 to step ST21 is stored in the memory. In step ST23, i is incremented, and the process returns to step ST3.

Steps ST24 to ST27 are processes of the point sequence moving unit 7. First, in step ST24, the point sequence moving unit 7 sets the index i of the first point of the point sequence command to be corrected to 2. In step ST25, an end determination is made. If i = n, the process is ended; otherwise, the process proceeds to step ST26. Step ST2
In 6 adds the amount multiplied by the gain K0 in the E _i to point sequence command P _i, to move the point sequence command P _i. The gain K0 is a correction gain and is set to an appropriate value of about 0.3 to 1.0. Usually, 0.5 is set. Step S
In T27, i is incremented, and the process returns to step ST25. The processing of steps ST25 to ST27 is repeated until i = n, and the processing shown in the flowchart of FIG.

FIG. 5 is a schematic diagram showing a state after the point sequence command P _i of FIG. 4 has been corrected by the point sequence moving unit 7 by E _i . The difference vectors are △ S _i-1 ', △ S _i ', △ S _{i + 1} '
Becomes smaller as described above, it can be seen that the trajectory by the point train command P _i is made smooth.

The point series interpolation unit 8 interpolation control and based on the sequence command P _i that have been fixed in a sequence of points moving unit 7 to the speed command, and outputs a position command of each axis of the servo control unit 9. Servo control unit 9
Controls the machine tool 2 in accordance with the position command. At this time, the point sequence command _Pi is modified so as to be smooth, so that smooth machining can be realized.

[0051] As described above, according to the first embodiment, calculates a difference vector is the curvature evaluation value from a few points before and after the modification point of the train command P _i that is input to the point sequence command correction unit 12 and, since a large value of the difference vector moves point sequence command so as to decrease, it is possible to modify the entire point sequence command P _i smooth trajectory.

In the case of a point sequence command P _i expressing a smooth locus such as an arc, the values of a plurality of difference vectors used as curvature evaluation values are substantially the same, and the correction amount of the point sequence command is small. It will be a small value. Therefore, an appropriate correction operation can be realized even in a curve such as the arc.

Further, the calculation of the correction amount is expressed by the following equation (114).
This can be realized by a small number of processes as in (115) and (116).

[0054] Further, since the limit in the maximum allowable error of the amount of movement of the point sequence command P _i in the correction amount limiting unit 6, not larger than necessary position error of train command points by modifying, processing accuracy A guaranteed corrective action can be realized.

Embodiment 2 In the first embodiment, the case where the number of point sequences selected by the evaluation range setting unit 4 is five has been described.
In the second embodiment, a case will be described in which the number of point sequences is seven. FIG. 6 is a block diagram showing a configuration of a numerical control device according to Embodiment 2 of the present invention.
Reference numeral 1a denotes a numerical control device according to the second embodiment, 4a denotes an evaluation range setting unit according to the second embodiment, 5a denotes a correction amount calculation unit according to the second embodiment, and 12a denotes a point sequence command correction unit according to the second embodiment. . The only difference from the numerical control device 1 according to the first embodiment shown in FIG. 1 is the difference in processing between the evaluation range setting unit 4a and the correction amount calculation unit 5a.

Next, the operation will be described. FIG. 7 is a flowchart showing the operation of the point sequence command correction unit 12a of the numerical controller 1a according to the second embodiment. Step ST1 in FIG.
Steps ST27 to ST27 are the same as those in the first embodiment shown in FIG. 3, and a description thereof will be omitted.

Steps ST3, 5, 7, and ST40 to ST45 are processing of the evaluation range setting section 4a. The evaluation range setting unit 4a according to the second embodiment selects seven consecutive points as the evaluation range. For example, assuming that the point to be corrected in FIG. 2 is P _i , the corrected point P _i and three points before and after the corrected point P _i , P _i-3 , P _i-2 , P _i-1 , P _{i + 1} , P _i
Processing for selecting _{i + 2} and P _{i + 3} is performed.

In step ST41, if i = 3, the process proceeds to step ST42, otherwise, the process proceeds to step ST42.
The process proceeds to 43. In step ST43, i = n-2
If so, the process proceeds to step ST44; otherwise, the process proceeds to step ST5.

Steps ST40, 42, 44, 45, 4
6, the correction point P _i and three points before and after the correction point P _i (P _i−3 , P
_i-2 , P _i-1 , P _{i + 1} , P _{i + 2} , P _{i + 3} ) are selected. Steps ST40 and ST42 are processing at the start point of the point sequence command, and steps ST44 and ST44 are performed. ST45
Is a process at the end point of the point sequence command, and step ST46 is a process other than the start point and the end point.

In step ST40, points P _i-2 and P _i-3 are set, in step ST42 point P _i-3 is set, in step ST44, point P _{i + 3} is set, and in step ST4.
In point 5, since the points P _{i + 2} and P _{i + 3} do not exist, the point sequence command is extrapolated using the following equation. Step _{ST40 P i-2 = P 3} -3P 2 + 3P 1 (201) P i-3 = 3P 3 -8P 2 + 6P 1 (202) step _{ST42 P i-3 = P 3} -3P 2 + 3P 1 (203) Step _{ST44 P i + 3 = 3P n} -3P n-1 + P n-2 (204) step _{ST45 P i + 2 = 3P n} -3P n-1 + P n-2 (205) P i + 3 = 6P n -8P _n-1 -3P _n-2 (206)

[0061] Step ST47 is a process of correction amount calculation unit 5a, calculates the correction amount E _i of the point P _i from the 7-point selected in step ST40,42,44,45,46. The correction amount E _i is the correction amount of the i-th point sequence command P _i , and X,
This is a vector including the correction amounts (ex _i , ey _i , ez _i ) of the Y and Z axes. The calculation method of the correction amount E _i of the point P _i in the point sequence command of FIG. 2 will be described below. FIG. 8 is an explanatory diagram of the correction operation of the point sequence command by the point sequence command correction unit 12a.

First, as shown in FIG. 8, the line segment vectors S _i-3 , S _i-2 , S _i-1 , S _i ,
Calculate S _{i + 1} and S _{i + 2} . S _i-2 , S _i-1 , S _i , S
_{i + 1} The equation (103), (104), (105),
Using (106), the following equations are used as S _i−3 and S _{i + 2} . _{S i-3 = P i-} 2 -P i-3 = (Px i-2 -Px i-3, Py i-2 -Py i-3, Pz i-2 -Pz i-3) = (Sx i _-3 , Sy _i-3 , Sz _i-3 ) (207) S _{i + 2} = P _{i + 3} −P _{i + 2} = (Pxi _{+ 3−} Pxi _{+ 2} , Py _{i + 3} −Py _{i + 2, Pz i + 3 -Pz i} + 2) = (Sx i + 2, Sy i + 2, Sz i + 2) (208)

Next, the first-order difference vectors △ S _i-2 , △ S
_i−1 , △ S _i , △ S _{i + 1} , △ S _{i + 2} are calculated. △ S
Equations (107) and (10) are used for _i−1 , △ S _i , and △ S _{i + 1.}
8), (109), and the following equations are used as △ Si _-2 and △ _{Si + 2} . ΔS _i−2 = S _i−2 −S _i−3 = (Sx _i−2 −Sx _i−3 , Sy _i−2 −Sy _i−3 , Sz _i−2 −Sz _i−3 ) (209) ΔS _{i + 2} = S _{i + 2} −S _{i + 1} = (Sx _{i + 2} −Sx _{i + 1} , Sy _{i + 2} −Sy _{i + 1} , Sz _{i + 2} −Sz _{i + 1} ) (210)

Next, as shown in FIG. 8, a second-order difference vector (difference vector) △△ S _i-2 , △△ S _i-1 , △△ S
_i , △△ S _{i + 1} are calculated. △△ S _i-2 = S _i-1- △ S _i-2 = S _i-1 -2S _i-2 + S _i-3 (211) △△ S _i-1 = △ S _i- △ S _{i- 1} = S _i -2S _i-1 + S _i-2 (212) △△ S _i = △ S _{i + 1-} △ S _i = S _{i + 1} -2S _i + S _i-1 (213) △△ S _{i + 1} = △ S _{i + 2} − △ S _{i + 1} = S _{i + 2} −2S _{i + 1} + S _i (214)

Since the point sequence commands P _{i-3 to} P _{i + 3 in} FIG. 4 are arranged at substantially equal intervals, the second-order difference vector △△
S _i−2 , △△ S _i−1 , △△ S _i , △△ S _{i + 1} are point sequence command trajectories P _{i−3 to} P _i , P _{i−2 to} P _{i + 1} , P
_{i-1 ~P i + 2,} P i ~P i + 3 between time values greater change in curvature is large, when the change of the curvature is small, a small value. Here, the second-order difference vector is used as a curvature evaluation value.

When the correction point P _i is moved by the correction amount E _i , the difference vectors in the equations (211), (212) and (213) are as follows. The corrected difference vector is represented by △△ S _i−2 ′, △△ S _i−1 ′, △△ S _i ′, △△
S _{i + 1} ′. Δ △ S _i−2 ′ = (S _i−1 + E _i ) −2S _i−2 + S _i−3 (215) Δ △ S _i−1 ′ = (S _i −E _i ) −2 (S _i−1 + E _i ) + S _i−2 (216) ΔS _i ′ = S _{i + 1} −2 (S _i −E _i ) + (S _i−1 + E _i ) (217) Δ △ S _{i + 1} ′ = S _{i + 2} -2S _{i + 1} + (S _i -E _i ) (218)

Here, equations (215), (216), and (2)
17), (218) difference vector {S _i-2 ′,}
In S _i−1 ′, △△ S _i ′, and △△ S _{i + 1} ′, in order to obtain the correction amount E _i for reducing the difference vector having a large value, the equations (113) and (114) of the first embodiment are used. Similarly, when the correction amount E _i that minimizes the sum of the squares of the respective axis components of the difference vector is calculated, the following equation corresponding to equation (117) is obtained. E _i = − (− P _i−3 + 6P _i−2 −15 P _{i− 1} +20 P _i −15 P _{i + 1} +6 P _{i + 2} −P _{i + 3} ) / 20 (219)

In step ST47, equation (219)
Processing is performed to calculate the correction amount E _i by.

As described above, according to the second embodiment, it is possible to extend the evaluation range of the point sequence command and calculate the correction amount using the higher-order difference vector for the curvature evaluation value. It is possible to correct the entire column command to a smoother trajectory.

Embodiment 3 Point sequence command correcting unit 12 according to the first embodiment, or point sequence command correcting unit 12 according to the second embodiment.
The operation of a works effectively when the intervals of the point sequence commands are substantially equal intervals, but when the intervals are not equal, the correspondence between the curvature evaluation value of the difference vector and the curvature of the locus formed by the point sequence commands becomes poor. However, the corrective action tends to stop working effectively. Therefore, in a third embodiment, a numerical control device having a point sequence command correction unit that effectively performs the operation of correcting the point sequence command even when the intervals of the point sequence commands are not equal will be described.

FIG. 9 is a block diagram showing a configuration of a numerical controller according to Embodiment 3 of the present invention.
Reference numeral 1b denotes a numerical controller according to the third embodiment, reference numeral 5b denotes a correction amount calculation unit according to the third embodiment, and reference numeral 12b denotes a point sequence command correction unit according to the third embodiment. The difference from the numerical control device 1 of the first embodiment shown in FIG. 1 is only the difference in the processing of the correction amount calculation unit 5b.

Next, the operation will be described. FIG. 10 shows a point sequence command correcting unit 12 of the numerical controller 1b according to the third embodiment.
6 is a flowchart illustrating the operation of FIG. The process shown in FIG. 10 performs the process of step ST50 instead of step ST9 in the process of the first embodiment shown in FIG.

The process of step ST50 is to calculate an effective correction amount even when the point sequence commands are not at equal intervals as shown in FIG. Here, the point selected by the evaluation range setting unit 4 is a correction point P _i and two points before and after the correction point P _i , P _i−2 ,
The case where the correction amount E _i is calculated assuming that the five points are P _i−1 , P _{i + 1} , and P _{i + 2} will be described. Of course, it is needless to say that the present invention can be similarly applied to the case where the correction amount is calculated by selecting each of three points before and after (a total of seven points) as in the second embodiment.

The formula for calculating the correction amount E _i of the point sequence command is obtained by the following procedure. First, equations (103), (104), and (10
5), line segment vectors S _i−2 ,
Calculate S _{i − 1} , S _i , and S _{i + 1} . Next, the line segment lengths L _i-2 , L _i-2 of the line segment vectors S _i-2 , S _i-1 , S _i , S _{i + 1
i−1} , L _i , and L _{i + 1} are obtained by the following equations. L _i-2 = sqrt (Sxi _-2 ＾ 2 + Syi _-2 ＾ 2 + Szi _-2 ＾ 2) (301) Li _-1 = sqrt (Sxi _-1 ＾ 2 + Syi _-1 ＾ 2 + Szi _{-1 ^ 2) (302) L i} = sqrt (Sx i ^ 2 + Sy i ^ 2 + Sz i ^ 2) (303) L i + 1 = sqrt (Sx i + 1 ^ 2 + Sy i + 1 ^ 2 + Sz i + 1 ^ 2) (304)

Next, the first-order difference vector △
Calculate Wi _-1 , △ _Wi , △ _{Wi + 1} . ΔW _i−1 = Q _i−1 S _i−1 −R _i−1 S _i−2 = (Q _i−1 Sx _i−1 −R _i−1 Sxi _i−2 , Q _i−1 Sy _{i− 1−} R _i−1 Sy _i−2 , Q _i−1 Sz _i−1 −R _i−1 Sz _i−2 ) (305) ΔW _i = Q _i S _i −R _i S _i−1 = (Q _{i Sx i -R i Sx i-} 1, Q i Sy i -R i Sy i-1, Q i Sz i -R i Sz i-1) (306) △ W i + 1 = Q i + 1 S i _{+1 -R i + 1 S i =} (Q i + 1 Sx i + 1 -R i + 1 Sx i, Q i + 1 Sy i + 1 -R i + 1 Sy i, Q i + 1 Sz i + ₁₋ R _{i + 1} Sz _i ) (307)

Here, Q _i−1 , R _i−1 , Q _i , R _i , Q
_{i + 1} and _{Ri + 1} are weight coefficients of the line segment vector, and are calculated using the length of the line segment vector as in the following equation. Q _i-1 = 2 / {L _i-1 (L _i-1 + L _i-2 )} (308-1) R _i-1 = 2 / ｛L _i-2 (L _i-1 + L _i-2 ) _{} (308-2) Q i = 2} / {L i (L i + L i-1)} (309-1) R i = 2 / {L i-1 (L i + L i-1)} (309- _{2) Q i + 1 = 2} / {L i + 1 (L i + 1 + L i)} (310-1) R i + 1 = 2 / {L i (L i + 1 + L i)} (310- 2)

As shown in FIG. 12, point sequence commands P _{i-2 to} P _{i-2 to} P
_{Even when i + 2} are arranged at unequal intervals, the first-order difference vectors △ W _i−1 , △ W _i , △ W _{i + 1} are weighted by the amounts related to the line segment lengths. △ W _i-1 ,
ΔW _i and ΔW _{i + 1} are point sequence command trajectories P _{i−2 to} P _i−2 respectively.
between _i, between _{P i-1 ~P i + 1} , the vector corresponding to the average curvature between P _i ~P _i + _2. Here, this difference vector is used as a curvature evaluation value.

When the correction point P _i is moved by the correction amount E _i , the three difference vectors in the equations (305), (306), and (307) are as follows. The corrected difference vectors are denoted by △ W _i−1 ′, △ W _i ′, and △ W _{i + 1} ′. ΔW _i−1 ′ = Q _i−1 (S _i−1 + E _i ) −R _i−1 S _i−2 (311) ΔW _i ′ = Q _i (S _i −E _i ) −R _i (S _i-1 + _Ei ) (312) ΔW _{i + 1} '= Q _{i + 1} S _{i + 1} -R _{i + 1} (S _i -E _i ) (313)

Here, equations (311), (312), and (31)
3) Difference vectors △ W _i−1 ′, △ W _i ′, △ W _{i + 1} ′
To determine the correction amount E _i to reduce the difference vector having a large value in the formula in the first embodiment (11
Similarly to (3) and (114), when the correction amount E _i that minimizes the sum of the squares of the respective axis components of the difference vector is calculated, the following equation corresponding to equation (117) is obtained. Can be _{E i = - (K 1 P} i-2 + K 2 P i-1 + K 3 P i + K 4 P i + 1 + K 5 P i + 2) / K 6 (314) where, K ₁ = Q _{i-1 R i-1 K 2 = -Q} i-1 2 -Q i-1 R i-1 -R i 2 + Q i R i K 3 = Q i-1 2 + Q i 2 + 2Q i R i + R i 2 + R i ₊₁ ² K ₄ = −Q _i R _i + Q _{i + 1} ² −Q _{i + 1} R _{i + 1} −R _{i + 1} ² K ₅ = Q _{i + 1} R _{i + 1} K ₆ = Q _i−1 ^{2 _{+ Q i 2 + 2Q i R}} i + R i 2 + R i + 1 2 (315) is.

[0080] The processing of calculating the correction amount E _i by step ST50 formula (314) is performed.

As described above, according to the third embodiment, the difference vector obtained from the line segment weighted by the quantity (line segment length) between the point sequence commands is used as the curvature evaluation value. Since the point sequence command is moved so that the large value of becomes small, it is possible to realize a favorable correction of the point sequence command that makes the point sequence command smooth even when the point sequence commands are not at equal intervals.

Embodiment 4 The method used in the first and second embodiments or the third embodiment cannot provide a sufficient effect when the curvature of the original trajectory changes greatly or when the interval between the point rows is large. Therefore, in the fourth embodiment, a numerical control device having a point sequence command correction unit that effectively performs a point sequence command correction operation even in a case where the curvature change is large within the evaluation range will be described. . The idea of this method is to remove an error component by locally applying the original curve using the same or similar curve as the original trajectory. Further, according to this method, the correction operation of the point sequence command works effectively even when the point sequence commands are not at equal intervals.

FIG. 13 is a block diagram showing a configuration of a numerical controller according to a fourth embodiment of the present invention. In the figure, reference numeral 1c denotes a numerical controller according to the fourth embodiment, and 5c denotes a correction amount calculation according to the fourth embodiment. The unit 12c is a point sequence command correcting unit according to the fourth embodiment. The difference from the numerical control device 1 of the first embodiment shown in FIG. 1 is only the difference in the processing of the correction amount calculation unit 5c.

Next, the operation will be described. FIG. 14 is a flowchart showing the operation of the point sequence command correction unit 12c of the numerical controller 1c according to the fourth embodiment. Point sequence command correction unit 12
The operation c is performed by using step ST60 instead of steps ST3, 4, 5, 6, and 8 in FIG.
The operation is the same as that of the first embodiment shown in FIG.

Hereinafter, step ST60 and step S60
The process of T61 will be described. The other processing is the same as the processing in FIG. 3 and the description is omitted.

First, the process of step ST60 will be described. In step ST60, the evaluation range of the point sequence is set, but unlike the first embodiment, the number of points is not fixed, and the front nf point and the rear nb point (total 1 + nf + nb)
Point). That is, in this embodiment, the number of points in the evaluation range to be selected does not necessarily have to be fixed, but can be adjusted. Of course, for simplicity, it is optional to fix nf = nb = 2 as in the first embodiment or nf = nb = 3 as in the third embodiment.

In general, as the number of points increases, a curve is applied to a wider range, so that the effect of making the locus smoother can be obtained. However, unless the number of points within the evaluation range is equal to or greater than the order of the curve + 2, there is no effect of smoothing the trajectory.
For example, if the degree of the curve is 2, the number of points needs to be 4 or more.

Next, the process of step ST61 will be described. In step ST61, within the evaluation range,
Fit an approximate curve. If the curve is denoted by P (t), the correction amount E _i is given by E _i = P (t _i ) −P _i (401). Where t is a curve parameter and t _i is P
_This is a curve parameter corresponding to _i .

Here, it is most appropriate to use the same type of curve as the original trajectory. For example, if the designer
If a quartic curve is used when designing with AD, it is optimal to apply a quartic curve. However, even if the designer designs using higher-order curves,
As a real design, when viewed locally, a low-order curve can be approximated with sufficient accuracy, and from the viewpoint of controlling the motor, the speed (corresponding to the first derivative of the curve) and the acceleration (corresponding to the second derivative of the curve) It is sufficient if the response is continuous. There is also a disadvantage that the higher the curve, the greater the amount of calculation. Therefore, it is not always appropriate to use a higher-order curve than necessary. That is, in practice, a low-order spline curve such as quadratic or cubic is almost enough. Conversely, if a first-order curve (that is, a straight line) is used, the effect of smoothing the trajectory cannot be expected, but rather the trajectory is deformed more than necessary, which is not appropriate. Hereinafter, a case where a quadratic spline curve is used will be described. The quadratic spline curve is given by the following equation. P (t) = {X (t) Y (t) Z (t)} (402) Here, X (t), Y (t) and Z (t) are respectively given as follows. _{X (t) = Cx 2 ·} t 2 + Cx 1 · t + Cx 0 (403) Y (t) = Cy 2 · t 2 + Cy 1 · t + Cy 0 (404) Z (t) = Cz 2 · t 2 + Cz 1 · t + Cz ₀ (405)

FIG. 15 is a schematic diagram showing an example of fitting a quadratic spline curve. In the figure, nb = nf =
2 and the evaluation ranges P _i−2 , P _i−1 , P _i , P
Approximate quadratic spline curves are applied to a total of five points, _{i + 1} and _{Pi + 2} . Correction amount E _i is calculated as unmodified P _i approaches the corresponding points on the secondary spline curve.

In equations (403), (404), and (405), the coefficients such as Cx ₂ , Cx ₁ , and Cx ₀ are at least 2
It can be obtained by using the multiplication method. That is, Cx ₂ ,
For Cx ₁ and Cx ₀ , {Cx ₂ , Cx ₁ , Cx ₀ } ′ = [inv (A ′ × A)] × (A ′ × b) (406) ). Here, A and b are given as follows. _{A = [f i-nb f} i-nb + 1 ... f i ... f i + nf-1 f i + nf] '(407) f i = {t i 2 t i 1}' (408) b = { _{px i-nb px i-nb} + 1 ... px i ... ... px i + nf-1 px i + nf} '(409) where, px _i is the x-coordinate value of a point of the index i.

The Y and Z axis components are obtained in the same manner. FIG. 16 is a graph showing an example in which this method is applied to a locus whose curvature changes halfway. At the point before correction (indicated by a cross), the curvature is large on the left side in the figure and small on the right side in the figure. The curvature changes around the boundary (near the center in the figure), and a step-like error component can be observed at that location. By applying this method, it can be seen that the corrected point (修正) has a smooth trajectory. In the above, the case where a quadratic spline curve is used has been described. However, even if a cubic or higher curve, a curve represented by a rational polynomial, or a curve such as an arc or an ellipse is used,
The same can be applied.

As described above, according to the fourth embodiment, correction of a point sequence command can be performed even for a point sequence command in which a change in curvature or a change in the interval between point sequence commands is large within the evaluation range. The operation can work effectively.

Embodiment 5 FIG. 17 is a block diagram showing a configuration of a numerical control device according to a fifth embodiment of the present invention. In the drawing, reference numeral 1d denotes a numerical control device according to the fifth embodiment, and 7d denotes a point sequence moving unit according to the fifth embodiment. is there. The point sequence moving unit 7d moves the position of the point sequence command of the point sequence command input unit 3 in accordance with the output of the correction amount limiting unit 6, and outputs the moved point sequence command to the evaluation range setting unit 4. . 12d
Denotes a point sequence command correction unit according to the fifth embodiment. The difference from the numerical control device 1 of the first embodiment shown in FIG. 1 is that the movement result in the point sequence moving unit 7 d is used for the next evaluation range setting in the evaluation range setting unit 4.

Next, the operation will be described. FIG. 18 shows a point sequence command correcting unit 12 of the numerical controller 1d according to the fifth embodiment.
It is a flowchart which shows operation | movement of d. The processing in steps ST1 to ST26 in FIG. 18 is the same as that in FIG. 3, and a description thereof will be omitted.

FIG. 18 shows steps ST22 and ST2 in FIG.
The difference is that there is no processing in steps 4, 25, and 27, and the processing in step ST26 is performed between the processing in step ST18 and the processing in step ST23. Using a column command P _i that modifications were made in step ST26 of FIG. 18, the following points P of the P _i
Calculation of the correction amount of _{i + 1} (steps ST3 to ST2)
1) is repeated.

As described above, according to the fifth embodiment, since the correction calculation of the next point sequence is performed using the corrected point sequence command, a smoother correction of the point sequence command can be realized. it can. In the above description, the case of repeating the method of the first embodiment has been described. However, the method of the second, third, or fourth embodiment is also described.
By making similar changes to the block diagrams and flowcharts, it is possible to improve performance by repetition.

Embodiment 6 FIG. In order to more accurately remove only errors when various types of trajectories are combined or when error components exist only at specific locations,
There is an effect that the evaluation range and the correction amount calculation method can be changed according to the properties of the point sequence such as the type of the trajectory and the presence or absence of an error. Therefore, in the sixth embodiment, a numerical control device having a point sequence command correction unit that can change the evaluation range and the correction amount calculation method will be described.

FIG. 19 is a block diagram showing a configuration of a numerical controller according to a sixth embodiment of the present invention. In the figure, reference numeral 1e denotes a numerical controller according to the sixth embodiment, and 12e denotes a point sequence command according to the sixth embodiment. The correction unit 13 is a trajectory determination unit that determines the normality of the trajectory of the input point sequence command. The difference from the numerical control device 1 of the first embodiment shown in FIG.

Next, the operation will be described. FIG. 20 shows the point sequence command correcting unit 12 of the numerical controller 1e according to the sixth embodiment.
9 is a flowchart illustrating an operation of a trajectory determination unit 13 of e. In step ST80, it is checked whether there is an error component. Whether there is an error component is determined based on the first-order difference vector described in the first embodiment.

In the places where steps, protrusions, rattles, etc. occur due to error components, the directions of the adjacent first-order difference vectors are all opposite. Therefore, the location where the direction of the acceleration vector is opposite and its surroundings are defined as locations where there is an error component. If there is no error component, it is not necessary to smooth it, so it is not included in the evaluation range. If there is an error component, the process proceeds to step ST81.

In step ST81, the interval of the point sequence is checked. The determination of the interval is made by setting an appropriate reference value and comparing it with the value. If the interval between the points is long, it is not appropriate to regard it as a part of a continuous curve, so that it is not included in the evaluation range. If the interval is short, the process proceeds to step ST82.

In step ST82, it is checked whether or not it is a corner. Whether it is a corner or not is determined by the first-order difference vector described in the first embodiment. A point where the first-order difference vector has a large value is a single point, and a point around which the first-order difference vector is small is a corner. If it is a corner, this point is not included in the evaluation range because it should pass through the corner strictly, not smooth. If it is not a corner, the process proceeds to step ST83, and is included in the evaluation range.

If the result determined as described above is “included in the evaluation range”, the evaluation range setting unit 4 includes the input point in the evaluation range, and conversely, the determined result is included in the “included in the evaluation range”. If not, the entered point is not included in the evaluation range.

Subsequently, the process proceeds to step ST85. In step ST85, it is checked whether or not the curvature is in a constant section. The curvature is substituted by the first-order difference vector described in the first embodiment. If the curvature is not constant, the process proceeds to step ST89, and a method by fitting a curve is selected.

If the curvature is constant, the process proceeds to step ST86. In step ST86, it is determined whether or not the intervals between the point sequences in the evaluation range are uniform. If the intervals are uniform, the process proceeds to step ST87, where a method using the primary difference or a method using the secondary difference is selected, and the method must be uniform. For example, the process proceeds to step ST88, and a method using a weighted primary difference or a method using a weighted secondary difference is selected.

The correction amount calculation unit 5 calculates the correction amount by the method selected here. In the above, in steps ST80, ST82, and ST85, the property of the trajectory is determined using the first-order difference vector, but the first-order difference weighted by the line segment length described in the third embodiment is used. Vector (△
_Wi ) may be used.

FIG. 21 is a schematic diagram showing the correction result of the point sequence command when the evaluation range and the correction amount calculation method are fixed. In the figure, crosses indicate points before correction, * marks indicate points before correction including errors, ○ marks indicate points after correction, broken lines indicate lines connecting points before correction, and solid lines indicate points after correction. Indicates a line. In this figure, since the evaluation range and the correction amount calculation method are fixed, the following problems occur. (1) A corner portion having no error is also smoothed and turns inward (a portion 1 in the figure). (2) The portion of the curve having no error is also smoothed and slightly inward (the portion in FIG. 2; it is hardly understood in the figure, but it is inward by about several percent of the point sequence interval). (3) In the vicinity of a place having a long dot row interval, the shape may be largely distorted (the place 3 in the figure).

FIG. 22 is a schematic diagram showing a correction result of a point sequence command when the method according to the sixth embodiment is applied. By using the above method, the above-mentioned problem is eliminated, and it is possible to precisely smooth only necessary portions.

As described above, according to the sixth embodiment, even when various types of trajectories are combined, or when an error component exists only at a specific location, only the error can be accurately detected. Can be removed.

[0111]

As described above, according to the first aspect of the present invention, the correction amount calculating unit calculates the curvature evaluation value corresponding to the curvature of the curve passing the point sequence command at a plurality of points within the evaluation range. In addition, since the correction amount of the point sequence command is calculated so as to reduce a large value among the plurality of curvature evaluation values, the entire point sequence command is smoothly corrected in the correction of the point sequence command. This makes it possible to effectively prevent a situation in which the machine tool is smoothened and the machine tool is damaged by unnecessary acceleration.

According to the second aspect of the present invention, the correction amount calculation unit uses a difference vector indicating a first-order or higher-order change amount of a line vector connecting continuous point sequence commands as the curvature evaluation value. By calculating the difference vector indicating the amount of change of the line segment vector, the amount of correction of the point sequence command can be calculated using a wide range of point sequence commands corresponding to the rank of the difference vector. Thus, there is an effect that an effective correction that makes the entire point sequence command smoother can be performed. Further, even in the case of a point sequence command expressing a smooth trajectory such as an arc, there is an effect that a smooth point sequence command can be obtained without deteriorating the trajectory as in the conventional method.

According to the third aspect of the present invention, the correction amount calculating section calculates each axis component of the correction amount such that the sum of squares of each axis component of the difference vector at a plurality of locations is minimized. Thus, by determining each axis component of the correction amount so as to minimize the sum of squares of each axis component of the difference vector at a plurality of locations, a large value among a plurality of curvature evaluation values is reduced. Accordingly, there is an effect that the effect of the invention described in claim 2 can be obtained.

According to the fourth aspect of the present invention, since the correction amount calculating section is provided with the correction amount limiting section for limiting the correction amount to the allowable error value or less, the correction of the point sequence command in the correction amount calculating section is performed. There is an effect that it is possible to prevent a situation in which the amount becomes a large value equal to or larger than the allowable error and machining failure by the machine tool or damage to the machine tool occurs.

According to the fifth aspect of the present invention, the correction amount calculation unit uses the difference vector calculated using the line vector weighted by the amount related to the length of the line vector as the difference vector. With this configuration, even when the point sequence commands are not at regular intervals, there is an effect that it is possible to realize a favorable correction of the point sequence command that smoothes the point sequence commands.

According to the sixth aspect of the present invention, the correction amount calculating section applies a quadratic or higher-order curve to the point sequence command within the evaluation range, and calculates the correction amount of the point sequence command so as to approach the curve. Therefore, a smooth point sequence command can be obtained without deteriorating the trajectory even for a point sequence command in which a change in the curvature or a change in the interval between the point sequence commands is large within the evaluation range. There is an effect that the column command can be effectively corrected.

According to the seventh aspect of the present invention, since the correction amount calculating section is configured to apply a quadratic curve to the point sequence command within the evaluation range, the correction amount calculation section satisfactorily follows the original curve with a small amount of calculation. There is an effect that correction to the point sequence command can be performed.

According to the eighth aspect of the present invention, the correction amount calculating unit is provided with the correction amount limiting unit for limiting the correction amount to the allowable error value or less, so that the correction of the point sequence command in the correction amount calculating unit is performed. There is an effect that it is possible to prevent a situation in which the amount becomes a large value equal to or larger than the allowable error and machining failure by the machine tool or damage to the machine tool occurs.

According to the ninth aspect of the present invention, the correction amount calculation unit is configured to use the corrected point sequence command for calculating the correction amount for the subsequent correction points. There is an effect that the correction can be realized.

According to the tenth aspect of the present invention, there is provided a trajectory judging section for judging the properties of the trajectory constituted by the input point sequence command, and the trajectory is set in the evaluation range setting section in accordance with the judged trajectory properties. Said evaluation range, and / or
Since the correction amount calculation method in the correction amount calculation unit is appropriately changed, even when various types of trajectories are combined, or when an error component exists only at a specific location, the correction amount calculation method is appropriately performed. Therefore, there is an effect that only an error can be removed and a good correction of the point sequence command can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a numerical controller according to Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram showing an example of a point sequence command.

FIG. 3 is a flowchart showing an operation of a point sequence command correction unit of the numerical control device according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of a correction operation of a point sequence command by a point sequence command correction unit of the numerical controller according to Embodiment 1 of the present invention;

[5] E _i train reference P _i point in Figure 4 by a sequence of points moving unit
FIG. 9 is a schematic diagram showing a state after only correction.

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

FIG. 7 is a flowchart showing an operation of a point sequence command correction unit of the numerical control device according to Embodiment 2 of the present invention.

FIG. 8 is an explanatory diagram of a point sequence command correcting operation of a point sequence command correction unit of a numerical control device according to a second embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of a numerical control device according to Embodiment 3 of the present invention.

FIG. 10 is a flowchart showing an operation of a point sequence command correction unit of the numerical control device according to Embodiment 3 of the present invention.

FIG. 11 is a schematic diagram showing a non-equidistant point sequence command.

FIG. 12 is an explanatory diagram of a correction operation of a point sequence command by a point sequence command correction unit of the numerical controller according to Embodiment 3 of the present invention;

FIG. 13 is a block diagram showing a configuration of a numerical controller according to Embodiment 4 of the present invention.

FIG. 14 is a flowchart showing an operation of a point sequence command correction unit of the numerical control device according to Embodiment 4 of the present invention.

FIG. 15 is a schematic diagram showing an example of fitting a quadratic spline curve in the fourth embodiment.

FIG. 16 is a graph showing an example of a correction result of a point sequence command in the fourth embodiment.

FIG. 17 is a block diagram showing a configuration of a numerical control device according to Embodiment 5 of the present invention.

FIG. 18 is a flowchart showing an operation of a point sequence command correction unit of the numerical controller according to Embodiment 5 of the present invention.

FIG. 19 is a block diagram showing a configuration of a numerical controller according to Embodiment 6 of the present invention.

FIG. 20 is a flowchart showing an operation of a trajectory determining unit of a point sequence command correcting unit of the numerical control device according to Embodiment 6 of the present invention.

FIG. 21 is a schematic diagram showing a correction result of a point sequence command when an evaluation range and a correction amount calculation method are fixed.

FIG. 22 is a schematic diagram showing a correction result of a point sequence command of the numerical controller according to Embodiment 6 of the present invention.

[Explanation of symbols]

1, 1a, 1b, 1c, 1d, 1e Numerical control device, 2
Machine tool, 3 point sequence command input unit, 4, 4a evaluation range setting unit, 5, 5a, 5b, 5c correction amount calculation unit, 6 correction amount limit unit, 7, 7d point sequence moving unit, 13 trajectory judgment unit, P _i-3 , _{Pi- 2} , _Pi-1 , _Pi , _{Pi + 1} , _{Pi + 2} ,
P _{i + 3} , P _{1 to} P _n point sequence commands, S _i-3 , S _i-2 , S
_i-1 , S _i , S _{i + 1} , S _{i + 2} line segment vectors, △
S _i−1 , △ S _i , △ S _{i + 1} , △ S _i−1 ′, △ S _i ′, △
S _{i + 1} ′, △ W _i−1 , △ W _i , △ W _{i + 1} first-order difference vector (difference vector), △△ S _i−2 , △△ S _i−1 , △
ΔS _i , ΔS _{i + 1} Second order difference vector (difference vector).

Claims (10)

[Claims] A point sequence command input unit for inputting a point sequence command representing a control position coordinate of a machine tool; an evaluation range setting unit for selecting several successive point sequence commands to set an evaluation range; Using a point sequence command within the evaluation range selected by the evaluation range setting unit, a correction amount calculation unit that calculates a correction amount of the point sequence command within the evaluation range, and the point sequence according to the calculated correction amount. A point sequence moving unit for moving a point sequence command input at the command input unit and outputting the result, wherein the correction amount calculating unit calculates a curvature evaluation value corresponding to a curvature of a curve passing through the point sequence command. Is calculated at a plurality of points within the evaluation range, and a correction amount of the point sequence command is calculated so as to reduce a large one among the plurality of curvature evaluation values. 2. The correction amount calculating unit according to claim 1, wherein a difference vector indicating a first-order or higher-order change amount of a line segment vector connecting the continuous point sequence commands is used as the curvature evaluation value. Numerical control device. 3. The correction amount calculation section calculates each of the axis components of the correction amount such that the sum of squares of each axis component of the difference vector at a plurality of locations is minimized.
Numerical control device as described. 4. The numerical control according to claim 1, further comprising a correction amount limiting unit that limits the correction amount in the correction amount calculation unit to a value equal to or less than an allowable error value. apparatus. 5. The correction amount calculation unit calculates a difference vector as
3. The numerical control device according to claim 2, wherein a difference vector calculated using a line segment vector weighted by an amount related to a length of the line segment vector is used. 6. A point sequence command input unit for inputting a point sequence command representing a control position coordinate of a machine tool, an evaluation range setting unit for selecting several continuous point sequence commands and setting an evaluation range, Using a point sequence command within the evaluation range selected by the evaluation range setting unit, a correction amount calculation unit that calculates a correction amount of the point sequence command within the evaluation range, and the point sequence according to the calculated correction amount. A point sequence moving unit that moves the point sequence command input at the command input unit and outputs the result, wherein the correction amount calculation unit applies a quadratic or higher-order curve to the point sequence command within the evaluation range. A numerical controller for calculating a correction amount of the point sequence command so as to approach the curve. 7. The correction amount calculation unit according to claim 6, wherein a quadratic curve is applied to the point sequence command within the evaluation range.
Numerical control device as described. 8. The numerical control device according to claim 6, further comprising a correction amount limiting unit that limits the correction amount in the correction amount calculation unit to a value equal to or less than an allowable error value. 9. The correction amount calculation unit according to claim 1, wherein the corrected point sequence command is used for calculating a correction amount for a subsequent correction point. Numerical control unit. 10. A trajectory judging unit for judging a property of a trajectory composed of an input point sequence command, wherein the evaluation range set by an evaluation range setting unit in accordance with the determined property of the trajectory; 2. The method according to claim 1, wherein the correction amount calculation method in the correction amount calculation unit is appropriately changed.
The numerical control device according to any one of claims 1 to 9.