Numerical control device

Abstract

The present invention provides a numerical control device that improves cycle time and improves machining surface quality. The numerical control device (1) comprises: a machining program reading unit (10) that generates a front end point sequence representing a path of a front end point of a tool possessed by a machine tool based on a read machining program; an interpolation control unit (11) that interpolates the front end point sequence generated by the machining program reading unit (10); a kinematic conversion unit (12) that performs coordinate conversion on the front end point sequence interpolated by the interpolation control unit (11) to obtain a control point sequence representing a path of control points for determining the position of the tool; a smoothing application unit (13) that smoothes the control point sequence obtained by the kinematic conversion unit (12) using predetermined parameters; and a drive control unit (14) that controls the drive of a machine tool (A) based on the control point sequence smoothed by the smoothing application unit (13).

Description

Technical Field

[0001] The present disclosure relates to a numerical control device. Background Art

[0002] Conventionally, numerical control devices for machine tools employ techniques for smoothing the path assigned by the tip of a tool in contact with a workpiece (e.g., see Patent Document 1). Patent Document 1 discloses known smoothing techniques, such as Bezier curves, B-spline curves, NURBS curves, simple averaging, and weighted averaging. These known techniques perform a tolerance check after smoothing. If the tolerance is exceeded (if the tolerance is not adhered to), the parameters are adjusted by changing them to within the tolerance.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-073097 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, in this conventional technique, since a path defined by a tip point that differs from the control point that determines the tool's position is smoothed, coordinate conversion of the smoothed path is required (from the tip point's coordinate system to the control point's coordinate system). As a result, the path defined by the control point may not be smooth. In this case, the machine tool's operation slows down, resulting in a reduction in cycle time or a decrease in machined surface quality.

[0008] Therefore, it is desirable to provide a numerical control device that can improve cycle time and machined surface quality.

[0009] Means for solving problems

[0010] One embodiment of the present disclosure is a numerical control device comprising: a machining program reading unit, which generates a leading end point sequence representing a path of leading end points of a tool possessed by a machine tool based on a read machining program; an interpolation control unit, which interpolates the leading end point sequence generated by the machining program reading unit; a kinematic conversion unit, which performs coordinate conversion on the leading end point sequence interpolated by the interpolation control unit to obtain a control point sequence representing a path of control points that determine the position of the tool; a smoothing application unit, which smoothes the control point sequence obtained by the kinematic conversion unit using predetermined parameters; and a drive control unit, which controls the drive of the machine tool based on the control point sequence smoothed by the smoothing application unit.

[0011] Effects of the Invention

[0012] According to one embodiment of the present disclosure, it is possible to provide a numerical control device capable of improving cycle time and machined surface quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a block diagram showing the functional configuration of the numerical control device according to the first embodiment.

[0014] Figure 2 This is a schematic diagram showing a path of a tool included in a machine tool, which is a control target of the numerical controller according to the first embodiment.

[0015] Figure 3 This is a flowchart illustrating processing executed by the numerical controller according to the first embodiment.

[0016] Figure 4 This is a block diagram showing the functional configuration of a numerical controller according to the second embodiment.

[0017] Figure 5 This is a flowchart illustrating processing executed by the numerical controller according to the second embodiment.

[0018] Figure 6 This is a block diagram showing the functional configuration of a numerical controller according to a third embodiment.

[0019] Figure 7 This is a flowchart illustrating processing executed by the numerical controller according to the third embodiment.

[0020] Figure 8 This is a block diagram showing the functional configuration of a numerical controller according to a fourth embodiment.

[0021] Figure 9 This is a flowchart illustrating processing executed by the numerical controller according to the fourth embodiment. DETAILED DESCRIPTION

[0022] Hereinafter, numerical controllers 1, 2, 3, and 4 according to the embodiments will be described with reference to the drawings. In the description of the second embodiment and subsequent embodiments, the same reference numerals are given to the components common to the other embodiments, and their description will be omitted.

[0023] [First embodiment]

[0024] First, use Figure 1 and Figure 2 , the structure of the numerical control device 1 is described. Figure 1 is a block diagram showing the functional configuration of the numerical control device 1 . Figure 2 It is a schematic diagram showing the path of a tool T included in a machine tool A, which is a control target of the numerical controller 1 .

[0025] Figure 1 The numerical controller 1 shown includes: an arithmetic processing unit (not shown) such as a CPU (Central Processing Unit); a main storage unit (not shown) such as a RAM (Random Access Memory) for storing data temporarily required when the arithmetic processing unit executes a program; an auxiliary storage unit (not shown) such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive) for storing various programs such as a machining program P; an input unit (not shown) such as a keyboard; an output unit (not shown) such as a monitor; and a communication unit (not shown) for communicating with a machine tool A.

[0026] The CPU (not shown) included in the numerical controller 1 implements various functions such as a machining program reading unit 10 , an interpolation control unit 11 , a kinematic conversion unit 12 , a smoothing application unit 13 , and a drive control unit 14 by executing various programs.

[0027] The machining program reading unit 10 generates a tool T (see FIG. 1 ) which is provided to the machine tool A based on the read machining program P. Figure 2 )'s leading endpoint list P tcp (t). Front point array P tcp (t) A path represented by a straight line, an arc, a parametric curve, etc. is expressed by a parametric curve. For example, when the machine tool A is a 5-axis processing machine, the front point sequence P tcp (t) is a 5-dimensional vector consisting of the coordinate values ​​of the X, Y, and Z axes and the coordinate values ​​of the rotation axes B and C. t is a parameter of the parametric curve.

[0028] The interpolation control unit 11 performs an interpolation operation on the front end point sequence P generated by the machining program reading unit 10. tcp (t) is interpolated.

[0029] The kinematic conversion unit 12 converts the front point sequence P interpolated by the interpolation control unit 11 into tcp (t) Coordinate transformation (kinematic transformation) is performed to obtain the tool T (refer to Figure 2 ) of the control point path of the control point column P mcn (t). P mcn (t) can be expressed as P mcn (t)=M·P tcp (t). For example, when the machine tool A is a 5-axis machining center, the P mcn(t) is a five-dimensional vector consisting of the coordinate values ​​of the X, Y, and Z axes and the coordinate values ​​of the rotation axes B and C. M is the transformation matrix for kinematic transformation.

[0030] The smoothing application unit 13 applies the control point sequence P obtained by the kinematic conversion unit 12 to the control point sequence P. mcn (t) Smoothing is performed with a predetermined parameter u. Thus, the smoothed control point sequence Q is obtained. mcn (t).Q mcn (t) can be expressed as Q mcn (t)=S(u)·P mcn (t)=S(u)·M·P tcp (t). The predetermined parameter u is a variable indicating the intensity of smoothing. S is an operation for performing smoothing. When u=0, S(u) does not perform smoothing. The larger u is, the greater the effect of smoothing, the smoother the path becomes, and conversely, the deviation from the original path becomes larger. For example, when S is a linear filter, its time constant is equivalent to u. u can be a fixed value or it can depend on the parameter t like u(t). Since u depends on the parameter t, for example, the effect of smoothing can be suppressed in corners and the effect of smoothing can be increased in free curves.

[0031] Specifically, the smoothing application unit 13 includes an inverse kinematics conversion unit 130 and a tolerance check unit 131 , and determines a predetermined parameter u through numerical calculation.

[0032] The inverse kinematics conversion unit 130 converts the control point sequence Q smoothed by the smoothing application unit 13 into mcn (t) Perform coordinate transformation (inverse kinematic transformation) to obtain the smoothed front point sequence Q tcp (t).Q tcp (t) can be expressed as Q tcp (t) = M -1 Q mcn (t) = M -1 ·S(u)·P mcn (t) = M -1 ·S(u)·M·P tcp (t). M -1 is the transformation matrix for inverse kinematic transformation and is the transformation matrix for inverse transformation of M.

[0033] Based on the front end point sequence P before coordinate conversion by the kinematic conversion unit 12 tcp (t) and the smoothed front end point sequence Q obtained by the inverse kinematics conversion unit 130 tcp (t), the tolerance inspection unit 131 performs tolerance inspection. tcp (t) and Q tcpThe difference d(t) between the two can be expressed as d(t) = |Q tcp (t)-P tcp (t)|. Set the maximum value of d(t) to d Max , and set the preset tolerance to T tcp , calculate the value that satisfies d Max ≤T tcp The maximum value of u (the maximum smoothing strength value) can be obtained from this. tcp A smooth path that is smoothed within a certain range.

[0034] The drive control unit 14 is based on the smoothed control point sequence Q mcn (t) controls the driving of the machine tool A. Specifically, the driving control unit 14 controls the driving of the machine tool A based on the smoothed control point sequence Q mcn (t) A servo drive unit (not shown) and a spindle drive unit (not shown) that drive the servo A1 and the spindle A2 included in the machine tool A are controlled.

[0035] Next, use Figure 3 The processing executed by the numerical controller 1 will be described. Figure 3 This is a flowchart illustrating processing executed by the numerical controller 1 .

[0036] like Figure 3 As shown, the processing executed by the numerical control device 1 includes a machining program reading step S10, an interpolation control step S11, a kinematic conversion step S12, a smoothing intensity setting step S13, a smoothing application step S14, an inverse kinematic conversion step S15, a tolerance checking step S16 and a drive control step S18.

[0037] In the machining program reading step S10, based on the read machining program P, a tip end point sequence P indicating the path of the tip end point of the tool T included in the machine tool A is generated. tcp (t).

[0038] In the interpolation control step S11, the front end point sequence P generated in the machining program reading step S10 is tcp (t) is interpolated.

[0039] In the kinematic conversion step S12, the front point sequence P interpolated in the interpolation control step S11 is converted into tcp (t) Coordinate transformation is performed to obtain a control point sequence P representing the path of the control points for determining the position of the tool T. mcn (t).

[0040] In the smoothing strength setting step S13, a parameter u, which is a value of the smoothing strength, is set. A small value is initially set, and the set value is gradually increased.

[0041] In the smoothing application step S14, the control point sequence P obtained by the kinematic conversion unit 12 is mcn (t) Smoothing is performed using the parameter u obtained in the previous step.

[0042] In the inverse kinematics conversion step S15, the control point sequence Q smoothed in the smoothing application step S14 is converted to mcn (t) Perform coordinate transformation to obtain the smoothed front point sequence Q tcp (t).

[0043] In the tolerance inspection step S16, based on the tip point array P before the coordinate conversion in the kinematic conversion step S12, tcp (t) and the smoothed front end point sequence Q obtained in the inverse kinematics conversion step S15 tcp (t) for tolerance check.

[0044] By repeatedly executing steps S13 to S16 according to the determination result in S17, the number of cells satisfying d is calculated by numerical calculation. Max ≤T tcp The maximum value of u is obtained, and the control point sequence Q smoothed with the maximum value of u is obtained. mcn (t).

[0045] In the drive control step S18, based on the finally obtained control point sequence Q mcn (t), controls the drive of machine tool A.

[0046] Thus, the numerical control device 1 includes a machining program reading unit 10 that generates a tip end point sequence P indicating a path of a tip end point of a tool T provided in the machine tool A based on the read machining program P. tcp (t); interpolation control unit 11, which is generated by the processing program reading unit 10 of the front point sequence P tcp (t) interpolation; kinematic conversion unit 12, which is interpolated by the interpolation control unit 11 after the front end point sequence P tcp (t) Coordinate transformation is performed to obtain a control point sequence P representing the path of the control points that determine the position of the tool T. mcn (t); Smoothing application unit 13, which is obtained by the kinematic conversion unit 12 of the control point column P mcn (t) performing smoothing with a predetermined parameter u; and driving the control unit 14 based on the control point sequence Q smoothed by the smoothing application unit 13. mcn (t), controls the drive of machine tool A.

[0047] In the numerical control device 1, the smoothing application unit 13 preferably includes an inverse kinematics conversion unit 130 for converting the control point sequence Q smoothed by the smoothing application unit 13 into an inverse kinematics conversion unit 130. mcn(t) Perform coordinate transformation to obtain the smoothed front point sequence Q tcp (t); and a tolerance checking section 131, which is based on the front end point array P before the coordinate conversion by the kinematic conversion section 12; tcp (t) and the smoothed front end point sequence Q obtained by the inverse kinematics conversion unit 130 tcp The difference between (t) is checked for tolerance and the predetermined parameter u is determined by numerical calculation.

[0048] According to the numerical controller 1 of this embodiment, by applying smoothing to the control points, the axis motion becomes smooth, thereby suppressing abrupt motion of the control points, thereby improving the cycle time and the quality of the machined surface.

[0049] [Second embodiment]

[0050] Next, use Figure 4 The configuration of the numerical controller 2 will be described. Figure 4 2 is a block diagram showing the functional configuration of the numerical controller 2. This embodiment differs from the first embodiment in that a smoothing application unit 23 that analytically determines a predetermined parameter u is provided instead of the smoothing application unit 13 that determines the predetermined parameter u by numerical calculation.

[0051] like Figure 4 As shown, a CPU (not shown) included in the numerical controller 2 realizes various functions such as the smoothing application unit 23 by executing various programs.

[0052] The smoothing application unit 23 applies the control point sequence P obtained by the kinematic conversion unit 12 to the control point sequence P. mcn (t) Smoothing is performed using a predetermined parameter u. In addition, the smoothing application unit 23 determines the predetermined parameter u analytically. That is, the smoothing application unit 23 calculates the value that satisfies d Max =T tcp u.

[0053] Next, use Figure 5 , the processing executed by the numerical control device 2 is described. Figure 5 This is a flowchart explaining the processing executed by the numerical controller 2 .

[0054] like Figure 5 As shown, the processing executed by the numerical controller 2 includes a machining program reading step S10 , an interpolation control step S11 , a kinematic conversion step S12 , a smoothing intensity calculation step S23 , a smoothing application step S14 , and a drive control step S18 .

[0055] In the smoothing strength calculation step S23, the smoothing strength value, i.e., the parameter u (satisfying d Max =T tcpu).

[0056] In addition, other steps are the same as those in the first embodiment.

[0057] Thus, the numerical control device 2 includes a machining program reading unit 10 that generates a tip end point sequence P indicating a path of a tip end point of a tool T provided in the machine tool A based on the read machining program P. tcp (t); interpolation control unit 11, which is generated by the processing program reading unit 10 of the front point sequence tcp (t) interpolation; kinematic conversion unit 12, which is interpolated by the interpolation control unit 11 after the front end point sequence P tcp (t) Coordinate transformation is performed to obtain a control point sequence P representing the path of the control points that determine the position of the tool T. mcn (t); Smoothing application unit 23, which is obtained by the kinematic conversion unit 12 of the control point column P mcn (t) performing smoothing with a predetermined parameter u; and driving the control unit 14 based on the control point sequence Q smoothed by the smoothing application unit 23. mcn (t), controls the drive of machine tool A.

[0058] In addition, in the numerical control device 2 , it is preferable that the smoothing application unit 23 analytically determines the predetermined parameter u.

[0059] According to the numerical controller 2 of this embodiment, the axis motion becomes smoother by smoothing the control points, thereby suppressing abrupt motion of the control points, thereby improving the cycle time and the quality of the machined surface.

[0060] [Third embodiment]

[0061] Next, use Figure 6 The configuration of the numerical controller 3 will be described. Figure 6 This is a block diagram showing the functional configuration of the numerical controller 3. The present embodiment differs from the first embodiment in that the smoothed control point sequence Q mcn (t) is interpolated instead of the front point sequence P before kinematic transformation tcp (t) is interpolated.

[0062] like Figure 6 As shown, the CPU (not shown) included in the numerical controller 3 realizes various functions such as the machining program reading unit 10, the kinematic conversion unit 12, the smoothing application unit 13, the interpolation control unit 11, and the drive control unit 14 by executing various programs.

[0063] The kinematic conversion unit 12 converts the front end point sequence P generated by the machining program reading unit 10 into tcp (t) Coordinate transformation is performed to obtain the tool T (refer to Figure 2 ) of the control point path of the control point column P mcn (t).

[0064] The interpolation control unit 11 performs smoothing on the control point sequence Q smoothed by the smoothing application unit 13. mcn (t) is interpolated.

[0065] The drive control unit 14 is based on the interpolated control point sequence Q mcn (t), controls the drive of machine tool A.

[0066] Next, use Figure 7 , the processing executed by the numerical control device 3 is described. Figure 7 This is a flowchart illustrating the processing executed by the numerical controller 3 .

[0067] like Figure 7 As shown, the processing executed by the numerical control device 3 includes a machining program reading step S10, a kinematic conversion step S12, a smoothing intensity setting step S13, a smoothing application step S14, an inverse kinematic conversion step S15, a tolerance checking step S16, an interpolation control step S11, and a drive control step S18.

[0068] In the kinematic conversion step S12, the front end point sequence P generated in the machining program reading step S10 is converted to the kinematics conversion step S12. tcp (t) Coordinate transformation is performed to obtain a control point sequence P representing the path of the control points for determining the position of the tool T. mcn (t).

[0069] In the interpolation control step S11, the control point sequence Q finally obtained is mcn (t) is interpolated.

[0070] In the drive control step S18, based on the control point sequence Q interpolated in the interpolation control step S11, mcn (t), controls the drive of machine tool A.

[0071] In addition, other steps are the same as those in the first embodiment.

[0072] Thus, the numerical control device 3 includes a machining program reading unit 10 that generates a tip end point sequence P indicating a path of a tip end point of a tool T provided in the machine tool A based on the read machining program P. tcp (t); Kinematic conversion unit 12, which is generated by the machining program reading unit 10 of the front point array P tcp (t) Coordinate transformation is performed to obtain a control point sequence P representing the path of the control points that determine the position of the tool T. mcn (t); Smoothing application unit 13, which is obtained by the kinematic conversion unit 12 of the control point column P mcn(t) Smoothing is performed with a predetermined parameter u; the interpolation control unit 11 performs smoothing on the control point sequence Q after being smoothed by the smoothing application unit 13. mcn (t) interpolation; and the driving control unit 14, which is based on the control point sequence Q after interpolation by the interpolation control unit 11 mcn (t), controls the drive of machine tool A.

[0073] In the numerical control device 3, it is preferable that the smoothing application unit 13 includes an inverse kinematics conversion unit 130 for converting the control point sequence Q smoothed by the smoothing application unit 13 into an inverse kinematics conversion unit 130. mcn (t) Perform coordinate transformation to obtain the smoothed front point sequence Q tcp (t); and a tolerance checking section 131, which is based on the front end point array P before the coordinate conversion by the kinematic conversion section 12; tcp (t) and the smoothed front end point sequence Q obtained by the inverse kinematics conversion unit 130 tcp (t), a tolerance check is performed, and the smoothing application unit 13 determines a predetermined parameter u through numerical calculation.

[0074] According to the numerical controller 3 of this embodiment, the axis movement becomes smooth by smoothing the control points. This can suppress the rapid movement of the control points, thereby improving the cycle time and the quality of the machined surface.

[0075] [Fourth embodiment]

[0076] Next, use Figure 8 The configuration of the numerical controller 4 will be described. Figure 8 1 is a block diagram showing the functional configuration of the numerical controller 4. This embodiment differs from the third embodiment in that a smoothing application unit 23 that determines the predetermined parameter u analytically is provided instead of the smoothing application unit 13 that determines the predetermined parameter u by numerical calculation.

[0077] like Figure 8 As shown, a CPU (not shown) included in the numerical controller 4 realizes various functions such as the smoothing application unit 23 by executing various programs.

[0078] Next, use Figure 9 The processing executed by the numerical controller 4 will be described. Figure 9 This is a flowchart illustrating the processing executed by the numerical controller 4 .

[0079] like Figure 9As shown, the processing executed by the numerical controller 4 includes a machining program reading step S10, a kinematic conversion step S12, a smoothing strength calculation step S23, a smoothing application step S14, an interpolation control step S11, and a drive control step S18. The processing contents of each step are as described above.

[0080] Thus, the numerical control device 4 includes a machining program reading unit 10 that generates a tip end point sequence P indicating a path of a tip end point of a tool T provided in the machine tool A based on the read machining program P. tcp (t); Kinematic conversion unit 12, which is generated by the machining program reading unit 10 of the front point array P tcp (t) Coordinate transformation is performed to obtain a control point sequence P representing the path of the control points that determine the position of the tool T. mcn (t); Smoothing application unit 23, which is obtained by the kinematic conversion unit 12 of the control point column P mcn (t) Smoothing is performed with a predetermined parameter u; the interpolation control unit 11 performs smoothing on the control point sequence Q after smoothing by the smoothing application unit 23. mcn (t) interpolation; and the driving control unit 14, which is based on the control point sequence Q after interpolation by the interpolation control unit 11 mcn (t), controls the drive of machine tool A.

[0081] In addition, in the numerical control device 4 , the smoothing application unit 23 preferably determines the predetermined parameter u analytically.

[0082] According to the numerical controller 4 of this embodiment, by applying smoothing to the control points, the axis motion becomes smooth, thereby suppressing abrupt motion of the control points, thereby improving the cycle time and the quality of the machined surface.

[0083] In addition, the present disclosure is not limited to the above-described embodiments, and various changes and modifications can be made.

[0084] For example, d may be obtained by a method different from that in the above-described embodiments. Max For example, P tcp (t1) and Q tcp The difference d(t1, t2) between the two can be expressed as d(t1, t2) = |Q tcp (t2)-P tcp (t1)|. At any t1, find the t2 where d1(t1, t2) is the minimum, and set the value of d at that time as d_ min (t1). That is, P tcp (t1) and Q tcp The difference d between (t1) and t2 is sometimes not the smallest. Then, find d_ min (t1) is the maximum t1, and d_ minThe value of d Max .

[0085] In addition, in the first and third embodiments, based on the front point array P tcp (t) and the front point series Q tcp The difference between (t) d(t) = |Q tcp (t)-P tcp (t)|Tolerance T tcp Check and calculate the value that satisfies d Max ≤T tcp The maximum value of u (the maximum smoothing strength value) can be used instead, according to the front point sequence P tcp (t) and the front point series Q tcp (t)d tcp (t)=|Q tcp (t)-P tcp (t)|Tolerance T tcp Check, and according to the control point list P mcn (t) and the control point sequence Q mcn (t)d mcn (t)=|Q mcn (t)-P mcn (t)|Tolerance T mcn Check and calculate to satisfy d tcp_Max ≤T tcp and d mcn_Max ≤T mcn The maximum value of u (the maximum smoothing strength value).

[0086] In this case, the tolerance inspection unit 131 is not only based on the tip point array P before the coordinate conversion by the kinematic conversion unit 12. tcp (t) and the smoothed front end point sequence Q obtained by the inverse kinematics conversion unit 130 tcp The difference between (t) tcp (t) is also based on the control point sequence P before smoothing by the smoothing application unit 13. mcn (t) and the control point sequence Q smoothed by the smoothing application unit 13 mcn The difference between (t) mcn (t) to conduct tolerance checks.

[0087] In addition, in the second and fourth embodiments, according to the front point array P tcp (t) and the front point series Q tcp The maximum value of the difference d(t) between the two values ​​is d Max , calculate the value that satisfies d Max =T tcp u, but it can also be replaced by the front point column P tcp(t) and the front point series Q tcp (t)d tcp The maximum value of (t) is d tcp_Max And the control point list P mcn (t) and the control point sequence Q mcn (t)d mcn The maximum value of (t) is d mcn_Max , calculate and satisfy d tcp_Max =T tcp and d mcn_Max =T mcn u.

[0088] Description of Reference Signs

[0089] 1, 2, 3, 4 numerical control device;

[0090] 10. Processing program reading unit;

[0091] 11 interpolation control unit;

[0092] 12 Kinematic Transformation Department;

[0093] 13,23 Smooth Application Department;

[0094] 130 Inverse Kinematics Transformation Department;

[0095] 131 Tolerance Inspection Department;

[0096] 14. Drive control unit;

[0097] A. Machine tools;

[0098] A1 servo;

[0099] A2 main axis;

[0100] T Tools;

[0101] P processing procedure;

[0102] P tcp (t) front point array;

[0103] P mcn (t) control point column;

[0104] S10: Read the machining program into the process;

[0105] S11 interpolation control process;

[0106] S12: kinematic conversion process;

[0107] S13 smoothing strength setting process;

[0108] S14 Smooth application process;

[0109] S15 inverse kinematics conversion process;

[0110] S16 Tolerance inspection process;

[0111] S18 drive control process;

[0112] S23 Smoothing strength calculation process.

Claims

1. A numerical control device, characterized in that: The numerical control device has: a machining program reading unit that generates a leading end point sequence indicating a path of a leading end point of a tool included in the machine tool based on the read machining program; an interpolation control unit that interpolates the front end point sequence generated by the machining program reading unit; a kinematic conversion unit that performs coordinate conversion on the front end point sequence interpolated by the interpolation control unit to obtain a control point sequence representing a path of control points that determine the position of the tool; a smoothing application unit configured to perform a smoothing process on the control point sequence obtained by the kinematic conversion unit using predetermined parameters to perform smoothing; as well as a drive control unit that controls the drive of the machine tool based on the control point sequence smoothed by the smoothing application unit, The smoothing application unit comprises: an inverse kinematics conversion unit for performing coordinate conversion on the control point sequence smoothed by the smoothing application unit to obtain the smoothed front end point sequence; as well as a tolerance checking unit that checks whether a maximum value of a difference between the tip point sequence before coordinate conversion by the kinematic conversion unit and the tip point sequence after smoothing obtained by the inverse kinematic conversion unit is less than a preset threshold value, and The smoothing application unit determines the predetermined parameter by numerical calculation so that the maximum value of the difference is equal to or less than the threshold value.

2. A numerical control device, characterized in that: The numerical control device has: a machining program reading unit that generates a leading end point sequence indicating a path of a leading end point of a tool included in the machine tool based on the read machining program; a kinematic conversion unit that performs coordinate conversion on the tip point sequence generated by the machining program reading unit to obtain a control point sequence representing a path of control points that determine the position of the tool; a smoothing application unit configured to perform a smoothing process on the control point sequence obtained by the kinematic conversion unit using predetermined parameters to perform smoothing; an interpolation control unit that interpolates the control point sequence smoothed by the smoothing application unit; and a drive control unit that controls the drive of the machine tool based on the control point sequence interpolated by the interpolation control unit, The smoothing application unit comprises: an inverse kinematics conversion unit for performing coordinate conversion on the control point sequence smoothed by the smoothing application unit to obtain the smoothed front end point sequence; as well as a tolerance checking unit that checks whether a maximum value of a difference between the tip point sequence before coordinate conversion by the kinematic conversion unit and the tip point sequence after smoothing obtained by the inverse kinematic conversion unit is less than a preset threshold value, and The smoothing application unit determines the predetermined parameter by numerical calculation so that the maximum value of the difference is equal to or less than the threshold value.

3. The numerical control device according to claim 1 or 2, characterized in that: The tolerance checking unit checks whether a maximum value of a difference between the control point sequence before smoothing by the smoothing application unit and the control point sequence after smoothing by the smoothing application unit is equal to or smaller than a preset threshold value.

4. A numerical control device, characterized in that: The numerical control device has: a machining program reading unit that generates a leading end point sequence indicating a path of a leading end point of a tool included in the machine tool based on the read machining program; an interpolation control unit that interpolates the front end point sequence generated by the machining program reading unit; a kinematic conversion unit that performs coordinate conversion on the front end point sequence interpolated by the interpolation control unit to obtain a control point sequence representing a path of control points that determine the position of the tool; a smoothing application unit configured to perform a smoothing process on the control point sequence obtained by the kinematic conversion unit using predetermined parameters to perform smoothing; as well as a drive control unit that controls the drive of the machine tool based on the control point sequence smoothed by the smoothing application unit, The smoothing application unit comprises: an inverse kinematics conversion unit that performs coordinate conversion on the control point sequence smoothed by the smoothing application unit to obtain the smoothed front end point sequence, The smoothing application unit analytically determines the predetermined parameter so that the maximum value of the difference between the front end point sequence before coordinate conversion by the kinematic conversion unit and the smoothed front end point sequence obtained by the inverse kinematic conversion unit is a preset threshold.

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