Numerical control system and interference detection auxiliary method

Abstract

The numerical control device (3) comprises: a pulse generating unit (34) for moving a plurality of mechanical elements of a machine tool (2) along a plurality of control axes according to a movement pulse for the machine tool (2); an interference checking unit (36) for performing interference checking operation on a plurality of interference checking object groups; and an interference checking auxiliary device (5) for assisting the interference checking operation. The interference checking auxiliary device (5) comprises: a first storage unit (51) for storing mechanical element-control axis correspondence information; a second storage unit (52) for storing axis affiliation information; and an inspection object group extracting unit (54a) for extracting one or more inspection object groups from all combinations of the plurality of mechanical elements according to the movement pulse, the mechanical element-control axis correspondence information, and the axis affiliation information.

Description

Technical Field

[0001] The present disclosure relates to a numerical control system and an interference detection auxiliary method. Background Art

[0002] A numerical controller moves the multiple mechanical elements (such as tools, worktables, and workpiece-holding fixtures) that make up a machine tool along multiple controlled axes according to a pre-created numerical control program, thereby machining the workpiece. Furthermore, the numerical controller includes an interference check function that concurrently performs interference check calculations to determine whether the various mechanical elements of the machine tool interfere with each other during machining (see, for example, Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6066041 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, conventional numerical controllers determine whether two mechanical elements constituting a predetermined inspection target group interfere with each other by performing an interference check calculation using shape information related to the shape of each mechanical element, position information related to the position of each mechanical element, and posture information related to the posture of each mechanical element. Furthermore, conventional numerical controllers need to perform this interference check calculation for multiple inspection target groups, which can be time-consuming.

[0008] Therefore, if the number of inspection target groups increases, it may not be possible to complete the interference check calculation for all inspection target groups within the control cycle of the machine tool by the numerical controller. In addition, it may not be possible to detect interference between mechanical elements at an appropriate timing.

[0009] The present disclosure has been made in view of the above-mentioned problems, and provides a numerical control system and an interference check assisting method for assisting an interference check operation in a numerical control device so as to complete the interference check operation in a short time.

[0010] Means for solving problems

[0011] One embodiment of the present disclosure is a numerical control system comprising: a numerical control device that moves multiple mechanical elements of a machine tool along multiple axes according to a movement instruction, and performs an interference check operation between two mechanical elements composed of a predetermined inspection object group; and an interference check auxiliary device that assists the interference check operation, the interference check auxiliary device comprising: a first storage unit that stores first information associating each axis in the machine tool with a mechanical element that moves along the axis among the multiple mechanical elements; a second storage unit that stores second information that specifies a subordinate relationship between the axes in the machine tool; and an inspection object group extraction unit that extracts one or more inspection object groups from all combinations of the multiple mechanical elements according to the movement instruction, the first information, and the second information.

[0012] One embodiment of the present disclosure is an interference check assisting method for assisting interference check operations in a numerical control device. The numerical control device moves multiple mechanical elements of a machine tool along multiple axes according to a movement instruction, and performs interference check operations between two mechanical elements combined by an inspection object group. The interference check assisting method obtains the movement instruction, first information associating each axis in the machine tool with a mechanical element moving along the axis among the multiple mechanical elements, and second information specifying a subordinate relationship between the axes in the machine tool, and extracts one or more of the inspection object groups from all combinations of the multiple mechanical elements based on the movement instruction, the first information, and the second information.

[0013] Effects of the Invention

[0014] According to one embodiment of the present disclosure, an inspection object group extraction unit extracts one or more inspection object groups from all combinations of multiple mechanical elements constituting a machine tool based on movement instructions in a numerical controller, first information associating each axis in the machine tool with a mechanical element that moves along the axis among multiple mechanical elements, and second information that specifies the subordinate relationship between the axes in the machine tool. Thus, it is possible to extract inspection object groups from all combinations of multiple mechanical elements by excluding combinations of mechanical elements that clearly do not interfere (for example, combinations of mechanical elements that move together along an axis based on a movement instruction). Furthermore, the numerical controller moves multiple mechanical elements along multiple axes based on the movement instructions, and performs interference check operations on the inspection object groups extracted by the inspection object group extraction unit. According to one embodiment of the present disclosure, it is possible to limit the inspection object groups for which interference check operations are performed to combinations of mechanical elements that clearly do not interfere, and thus, the operation can be completed in a shorter time than when the interference check operation in the numerical controller is performed on all combinations. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1This is a schematic diagram of a numerical control system according to the first embodiment of the present disclosure.

[0016] Figure 2 This is a diagram showing an example of a machine tool.

[0017] Figure 3 This figure shows an example of display based on the machine structure tree, showing machine element-controlled axis correspondence information and axis dependency information.

[0018] Figure 4A This is a diagram showing an example of mechanical element-controlled axis correspondence information and axis dependency information.

[0019] Figure 4B It means in Figure 4A The diagram shows an example of mechanical element-controlled axis correspondence information and axis dependency information in which the first to fourth mechanical elements are classified into a dependent mechanical element group and a stationary mechanical element group.

[0020] Figure 5 This is a flowchart showing the specific procedure of the inspection object group extraction process.

[0021] Figure 6 This is a diagram for explaining a process of calculating a priority using the first priority calculation algorithm.

[0022] Figure 7 This is a diagram for explaining a process of calculating a priority using the second priority calculation algorithm.

[0023] Figure 8 This is a diagram for explaining a process of calculating a priority using the third priority calculation algorithm.

[0024] Figure 9 This is a diagram showing an example of interference check support information generated by the interference check support device.

[0025] Figure 10 This is a schematic diagram of a numerical control system according to a second embodiment of the present disclosure. DETAILED DESCRIPTION

[0026] <First embodiment>

[0027] Hereinafter, a numerical control system according to a first embodiment of the present disclosure will be described with reference to the drawings.

[0028] Figure 1 This is a schematic diagram of the numerical control system 1 according to the present embodiment.

[0029] A numerical control system 1 includes a machine tool 2 and a numerical control device (CNC) 3 that controls the machine tool 2 .

[0030] Machine tool 2 includes multiple mechanical elements having a predetermined three-dimensional shape, including a tool, a worktable, a support for the tool, and a fixture for holding a workpiece; and multiple servo motors 2a, 2b, ..., 2n that move each mechanical element along multiple control axes. Machine tool 2 drives multiple servo motors 2a, ..., 2n based on movement pulses transmitted from numerical controller 3, thereby moving the multiple mechanical elements along the multiple control axes and machining a workpiece (not shown). Examples of machine tool 2 include, but are not limited to, lathes, drilling machines, milling machines, grinding machines, laser processing machines, and injection molding machines.

[0031] The numerical controller 3 is a computer composed of hardware such as a CPU (Central Processing Unit), an auxiliary storage unit such as an HDD (Hard Disk Drive) or SSD (Solid State Drive) that stores various programs, a main storage unit such as RAM (Random Access Memory) for storing data temporarily required when the processing unit executes the programs, an operation unit such as a keyboard for the operator to perform various operations, and a display unit such as a monitor that displays various information to the operator.

[0032] The numerical controller 3 implements various functions of the machining program memory 31 , the command analysis unit 32 , the interpolation unit 33 , the pulse generation unit 34 , the position and posture calculation unit 35 , the interference check unit 36 ​​, the shape storage unit 37 , and the interference check assisting device 5 through the hardware configuration.

[0033] The machining program memory 31 stores a numerical control program including commands for moving each mechanical element of the machine tool 2 along each control axis (including translation and rotation). The numerical control program is described in a predetermined programming language (eg, G-code).

[0034] The command analysis unit 32 reads and analyzes the numerical control program stored in the machining program memory 31 block by block, and generates movement command data instructing the movement of each control axis of the machine tool 2 based on the analysis result. The command analysis unit 32 sends the generated movement command data to the interpolation unit 33.

[0035] The interpolation unit 33 generates interpolation data by performing interpolation calculations on points on the command path at a predetermined interpolation cycle based on the movement command data sent from the command analysis unit 32 . The interpolation unit 33 sends the generated interpolation data to the pulse generation unit 34 .

[0036] Based on the interpolation data sent from the interpolation unit 33, the pulse generation unit 34 generates movement commands for the machine tool 2, that is, movement pulses for each of the servo motors 2a, ..., 2n of the machine tool 2, at the interpolation cycle described above. The pulse generation unit 34 inputs the movement pulses generated in this manner into the servo motors 2a, ..., 2n, thereby moving the multiple mechanical elements of the machine tool 2 along the multiple control axes. Furthermore, if the interference check calculation (described later) performed by the interference check unit 36 ​​determines that any of the multiple mechanical elements is causing interference, the pulse generation unit 34 stops generating movement pulses and inputting them to the machine tool 2 to prevent such interference.

[0037] Furthermore, pulse generator 34 generates movement pulses in each interpolation cycle based on interpolation data as described above, and transmits movement pulses scheduled to be input to machine tool 2 in this interpolation cycle to position and posture calculator 35 before inputting them to machine tool 2 .

[0038] Based on the movement pulses sent from the pulse generator 34 at each interpolation cycle, the position and posture calculation unit 35 calculates an axis movement amount vector (e.g., the axis movement amount per unit time (e.g., per interpolation cycle)) for each control axis when the control axis is moved in response to the movement pulses; a pre-movement position vector (e.g., the position of each mechanical element before the control axis is moved in response to the movement pulses); a post-movement position vector (e.g., the position of each mechanical element after the control axis is moved in response to the movement pulses); and post-movement posture information (e.g., the posture of each mechanical element after the control axis is moved in response to the movement pulses). The position and posture calculation unit 35 transmits the calculated axis movement amount vector for each control axis and the pre-movement position vector for each mechanical element to the interference check supporting device 5. Furthermore, the position and posture calculation unit 35 transmits the calculated post-movement position vector and post-movement posture information for each mechanical element to the interference check unit 36.

[0039] Furthermore, the orientation and norm of the axis movement vector calculated by the position and posture calculation unit 35 are defined as follows. When the control axis is a rectilinear axis that causes the mechanical element to translate along its axis, the orientation of the axis movement vector is parallel to the control axis, and the norm of the axis movement vector is equal to the distance traveled per unit time along the axis of the control axis [mm]. Furthermore, when the control axis is a rotary axis that causes the mechanical element to rotate about its axis, the angular velocity vector of the control axis is used as the axis movement vector. That is, when the control axis is a rotary axis, the orientation of the axis movement vector is parallel to the control axis, and the norm of the axis movement vector is equal to the rotation angle [rad] of the control axis per unit time. Hereinafter, the norm of the axis movement vector will also be referred to simply as "axis movement."

[0040] Shape storage unit 37 stores shape information related to the shapes of the various mechanical elements that comprise machine tool 2. Furthermore, when movement pulses having the same interpolation cycle as the movement pulses input from pulse generator 34 to machine tool 2 are input to position and posture calculator 35 as described above, a slight margin is preferably added to the shape information stored in shape storage unit 37 to prevent interference from occurring even if the interference check calculation by interference check unit 36 ​​fails to complete within the interpolation cycle. Specifically, the shape information stored in shape storage unit 37 is preferably generated based on mechanical elements that are slightly larger than the actual mechanical elements.

[0041] While the movement pulses generated by the pulse generator 34 are continuously input to the machine tool 2 as described above, the interference check unit 36 ​​performs interference check calculations on multiple inspection target groups to determine whether the multiple mechanical elements constituting the machine tool 2 interfere with each other. Here, an inspection target group is a combination of two of the multiple mechanical elements constituting the machine tool 2. Therefore, if the total number of mechanical elements constituting the machine tool 2 is N, the total number of inspection target groups is N(N-1) / 2.

[0042] More specifically, the interference check unit 36 ​​performs an interference check calculation using a known interference check algorithm (e.g., a separate-axis method) based on the post-movement position vector and post-movement posture information transmitted from the position and posture calculation unit 35 at each interpolation cycle, the interference check auxiliary information generated at each interpolation cycle by the interference check auxiliary device 5 through a process described later, and the shape information stored in the shape storage unit 37. While the movement pulses generated by the pulse generation unit 34 are continuously input to the machine tool 2, the interference check unit 36 ​​determines whether interference occurs between the multiple mechanical elements constituting the machine tool 2. If the interference check calculation determines that interference has occurred, the interference check unit 36 ​​notifies the pulse generation unit 34 of this fact and stops the generation of movement pulses and the input of movement pulses to the machine tool 2 before interference occurs.

[0043] The interference check support device 5 includes a first storage unit 51 , a second storage unit 52 , a third storage unit 53 , and a check support information generating unit 54 , and uses these to generate interference check support information for supporting interference check calculation in the interference check unit 36 ​​.

[0044] In the first storage unit 51, mechanical element-control axis correspondence information is stored in any form such as a mechanical structure tree or a table, which associates each control axis in the machine tool 2 with a mechanical element that moves along the control axis associated with the control axis when the control axis is moved. Figure 3 The case where the mechanical element-control axis correspondence information is stored in the mechanical structure tree format as shown in the example will be described.

[0045] The second storage unit 52 stores information on the subordinate relationships between the control axes of the machine tool 2 in any form such as a machine structure tree or a table. Figure 3 The following describes a case where the information on the dependency relationship of each axis is stored in the form of a machine structure tree as illustrated.

[0046] Next, refer to Figure 2 and Figure 3 A specific example of the mechanical element-controlled axis correspondence information and the axis-subordinate relationship information stored in these storage units 51 and 52 will be described.

[0047] Figure 2 This is a diagram showing an example of the machine tool 2 . Figure 2 The illustrated machine tool 2 is capable of moving six mechanical elements 21, 22, 23, 24, 25, and 26 along five control axes X, Y, Z, A, and C. The fifth mechanical element 25 is a fixture that supports a workpiece not shown in the figure, and the sixth mechanical element 26 is a workbench that supports the fifth mechanical element 25. These fifth mechanical elements 25 and sixth mechanical elements 26 are, for example, capable of rotating and moving around a control axis C extending in a vertical direction. The fourth mechanical element 24 is a tool for processing the workpiece supported by the fifth mechanical element 25. The third mechanical element 23 is a support that supports the fourth mechanical element 24 at its front end. The second mechanical element 22 is a support that supports the base end of the third mechanical element 23 so that it can rotate freely around a control axis A extending along a horizontal plane. The first mechanical element 21 is a support that supports the second mechanical element 22 so that it can move freely in parallel along a control axis Z along a vertical direction and control axes X and Y that are orthogonal to each other in the horizontal plane. That is, in Figure 2 In the example, the control axes X, Y, and Z are linear axes, and the control axes A and C are rotation axes.

[0048] That is, in Figure 2 In the illustrated machine tool 2, the fifth and sixth mechanical elements 25 and 26 rotate integrally and jointly along the control axis C. Furthermore, the first, second, third, and fourth mechanical elements 21, 22, 23, and 24 rotate integrally and jointly along the control axes X, Y, and Z, and the third and fourth mechanical elements 23 and 24 rotate integrally and jointly along the control axis A.

[0049] Figure 3 Yes Figure 2 The diagram shows an example of displaying the mechanical element-controlled axis correspondence information and the axis dependency information in the machine tool 2 based on the machine structure tree. Figure 2 In the machine tool 2 shown as an example, the control axis C can be moved independently of the control axes X, Y, Z, and A. Figure 3As shown in the mechanical structure tree, the control axis C and the control axes X, Y, Z, and A are independently subordinate to the route R. Figure 2 In the machine tool 2 shown in the example, if the control axes X, Y, and Z are moved, the control axis A also moves. However, even if the control axis A is moved, the control axes X, Y, and Z do not move. In other words, the control axis A is inferior to the control axes X, Y, and Z. Therefore, if Figure 3 As shown in the mechanical structure tree, the control axis A is subordinate to the control axes X, Y, and Z.

[0050] In addition, the fifth mechanical element 25 and the sixth mechanical element 26 rotate integrally along the control axis C. Therefore, Figure 3 As shown in the mechanical structure tree of FIG, these mechanical elements 25 and 26 are associated with the control axis C. In addition, the third mechanical element 23 and the fourth mechanical element 24 rotate integrally along the control axis A which is lower than the control axes X, Y, and Z. Therefore, as shown in FIG. Figure 3 As shown in the mechanical structure tree of FIG, these mechanical elements 23 and 24 are associated with the control axis A. In addition, the first mechanical element 21 and the second mechanical element 22 rotate integrally along the control axes X, Y, and Z. Figure 3 As shown in the mechanical structure tree of FIG, these mechanical elements 21 and 22 are associated with the lowest control axis Z among the control axes X, Y, and Z.

[0051] return Figure 1 The inspection support information generating unit 54 includes an inspection target group extracting unit 54a, which extracts one or more inspection target groups from all combinations of the multiple mechanical elements of the machine tool 2; and a priority calculating unit 54b, which calculates the priorities of the multiple inspection target groups, more specifically, the multiple inspection target groups extracted by the inspection target group extracting unit 54a. Here, the priorities of the multiple inspection target groups are integer values ​​that determine the order in which the interference check calculations are performed sequentially for the multiple inspection target groups in the interference check unit 36. Hereinafter, the priorities are assumed to be lower in ascending order, starting with the smallest value.

[0052] The third storage unit 53 stores interference check auxiliary information formed by combining information on the inspection target groups extracted by the inspection target group extraction unit 54 a and information on the priority determined for each inspection target group by the priority calculation unit 54 b .

[0053] The inspection object group extraction unit 54a removes combinations that do not require interference check operations from all combinations of multiple mechanical elements based on the axis movement amounts of each control axis sent from the position and posture calculation unit 35 according to the interpolation cycle, the mechanical element-control axis correspondence information stored in the first storage unit 51, and the axis subordination information stored in the second storage unit 52, thereby extracting one or more inspection object groups.

[0054] First, the inspection target group extraction unit 54a identifies, from among the multiple control axes, the control axes that have been moved by the movement pulses as movement control axes, based on the axis movement amounts of each control axis sent from the position and posture calculation unit 35. More specifically, the inspection target group extraction unit 54a identifies as movement control axes those control axes whose axis movement amounts (norm of the axis movement amount vector) are not zero.

[0055] Next, the inspection target group extraction unit 54a classifies the multiple machine elements constituting the machine tool 2 into a dependent machine element group and a stationary machine element group based on the machine element-control axis correspondence information and the axis dependency information. The dependent machine element group includes machine elements that move with the motion control axis, while the stationary machine element group includes machine elements that do not move even when the motion control axis is moved. More specifically, the inspection target group extraction unit 54a classifies machine elements associated with the motion control axis and its subordinate control axes into the dependent machine element group, and classifies all machine elements not belonging to the dependent machine element group into the stationary machine element group.

[0056] Here, all the mechanical elements belonging to the subordinate mechanical element group move with the motion-controlled axis. Therefore, it can be seen that the combination of mechanical elements belonging to the subordinate mechanical element group will not cause interference even if the interference check operation is not performed, and therefore is excluded from the inspection target group. Furthermore, all the mechanical elements belonging to the stationary mechanical element group will not move even if the motion-controlled axis is moved. Therefore, it can be seen that the combination of mechanical elements belonging to the stationary mechanical element group will not cause interference even if the interference check operation is not performed, and therefore is excluded from the inspection target group. Therefore, the inspection target group extraction unit 54a extracts combinations of mechanical elements belonging to the subordinate mechanical element group and mechanical elements belonging to the stationary mechanical element group as inspection target groups. In other words, the inspection target group extraction unit 54a extracts, from all combinations of the plurality of mechanical elements, combinations other than combinations of mechanical elements belonging to the subordinate mechanical element group and combinations of mechanical elements belonging to the stationary mechanical element group as inspection target groups. The inspection target group extraction unit 54a stores the list of inspection target groups extracted through the above process (hereinafter referred to as the "inspection target group list") in the third storage unit 53.

[0057] Here, refer to Figure 4A as well as Figure 4B The specific process of extracting the inspection object group by the inspection object group extraction unit 54a as described above will be described with reference to a specific example.

[0058] Figure 4A This is a diagram showing an example of mechanical element-control axis correspondence information and axis subordination information. Figure 4AIn the example shown, the machine tool can move the first mechanical element, the second mechanical element, the third mechanical element, and the fourth mechanical element along the first control axis, the second control axis, the third control axis, the fourth control axis, the fifth control axis, and the sixth control axis. Figure 4A In the example of the axis dependency information shown, the first to fourth control axes and the fifth to sixth control axes can move independently. In addition, the fifth control axis is subordinate to the sixth control axis, the second to fourth control axes are subordinate to the first control axis, the third control axis and the fourth control axis are subordinate to the first control axis and the second control axis respectively, and the second control axis is subordinate to the first control axis. In addition, Figure 4A In the example of the mechanical element-control axis correspondence information shown, the first mechanical element is associated with the first control axis, the second mechanical element is associated with the fourth control axis, the fourth mechanical element is associated with the sixth control axis, and the third mechanical element is associated with the fifth control axis.

[0059] Figure 4B It means in Figure 4A The diagram shows the case where the first to fourth mechanical elements are classified into a dependent mechanical element group and a stationary mechanical element group under the mechanical element-controlled axis correspondence information and the axis dependency relationship information. Figure 4B In the example, the first control axis among the first to sixth control axes is used as the movement control axis. Figure 4B As shown, the first and second mechanical elements associated with the first control axis as the moving control axis and the second, third, and fourth control axes subordinate to the first control axis are classified as the subordinate mechanical element group, and the third and fourth mechanical elements that do not belong to the subordinate mechanical element group among all the mechanical elements are classified as the stationary mechanical element group. Figure 4B In the example shown, of all combinations of the first to fourth mechanical elements (a total of 6 combinations of the first and second mechanical elements, the first and third mechanical elements, the first and fourth mechanical elements, the second and third mechanical elements, the second and fourth mechanical elements, and the third and fourth mechanical elements), 4 combinations of the first and third mechanical elements, the first and fourth mechanical elements, the second and third mechanical elements, and the second and fourth mechanical elements are extracted as the inspection object group.

[0060] return Figure 1 When there are multiple movement control axes, the inspection object group extraction unit 54a extracts the union of the inspection object groups extracted according to the above process under each movement control axis as the inspection object group.

[0061] Figure 5 : is a flowchart showing the specific process of the inspection object group extraction processing in the inspection object group extraction unit 54a. Figure 5In the process shown, the total number of control axes is set to N (N is an integer greater than or equal to 2). The inspection object group extraction unit 54a executes the following operation based on the new axis movement amount received from the position and posture calculation unit 35: Figure 5 The inspection object group extraction process is shown.

[0062] First, in S1, the inspection target group extraction unit 54a sets the value of the control axis counter C to 1 and then moves on to S2. In S2, the inspection target group extraction unit 54a determines whether the axis movement amount of the Cth control axis associated with the counter C is not zero, based on the axis movement amount for each control axis sent from the position and posture calculation unit 35. If the result of the inspection target group extraction unit 54a in S2 is yes, the process moves on to S3; if not, the process moves on to S5.

[0063] In S3, the inspection target group extraction unit 54a sets the C-th control axis as the moving control axis, thereby classifying the multiple mechanical elements into a dependent mechanical element group and a stationary mechanical element group according to the above-described process, and then proceeds to S4. In S4, the inspection target group extraction unit 54a adds all combinations of mechanical elements belonging to the dependent mechanical element group and mechanical elements belonging to the stationary mechanical element group as inspection target groups to the inspection target group list in the third storage unit 53, and then proceeds to S5.

[0064] In S5, the inspection target group extraction unit 54a determines whether the value of the control axis counter C is equal to the total number of control axes N. If the determination result of S5 is negative, the inspection target group extraction unit 54a moves to S6, increments the control axis counter C by 1, and then returns to S2. If the determination result of S5 is positive, the inspection target group extraction unit 54a ends. Figure 5 The inspection object group extraction process is shown.

[0065] According to the inspection target group extraction process described above, when there are multiple movement control axes, the union of multiple combinations of multiple mechanical elements classified into dependent mechanical element groups and stationary mechanical element groups under each movement control axis is extracted as the inspection target group.

[0066] return Figure 1 The priority calculation unit 54b calculates priorities for the multiple inspection target groups extracted by the inspection target group extraction unit 54a in descending order of the inspection target group with the highest likelihood of interference, based on the axis movement vectors of each control axis and the pre-movement position vectors of each mechanical element, which are transmitted from the position and posture calculation unit 35 at the interpolation cycle, and the mechanical element-control axis correspondence information stored in the first storage unit 51. The priority calculation unit 54b can calculate priorities for the multiple inspection target groups using any one of the first, second, and third priority calculation algorithms described below, or a combination of these.

[0067] <First priority calculation algorithm>

[0068] Under the first priority calculation algorithm, the priority calculation unit 54b calculates the priorities of multiple inspection target groups based on the axis movement amounts of each control axis transmitted from the position and posture calculation unit 35. More specifically, the priority calculation unit 54b calculates the mechanical element priority for each mechanical element associated with each control axis via mechanical element-control axis correspondence information, in descending order, starting with the control axis with the largest axis movement amount. Next, the priority calculation unit 54b calculates the priorities of the inspection target groups containing each mechanical element, in descending order, starting with the mechanical element with the highest calculated mechanical element priority. In other words, under the first priority calculation algorithm, the priority calculation unit 54b determines that there is a high probability of interference occurring in an inspection target group containing a mechanical element associated with a control axis with a large axis movement amount per unit time, and increases the priority of the inspection target group containing such a mechanical element.

[0069] However, the dimension of the axis movement amount is different when the control axis is a straight axis and when the control axis is a rotation axis. More specifically, when the control axis is a straight axis, the axis movement amount is the movement distance, and when the control axis is a rotation axis, the axis movement amount is the rotation angle. Therefore, it is impossible to directly compare the size of the axis movement amount for the straight axis and the axis movement amount for the rotation axis. Therefore, under the first priority calculation algorithm, the priority of each inspection object group is calculated by dividing it into an inspection object group that includes a rotating mechanical element and an inspection object group that does not include the rotating mechanical element. The rotating mechanical element is a mechanical element associated with the rotating axis through the mechanical element-control axis correspondence information. More specifically, it is more difficult for a rotating axis to notice interference than a straight axis. Therefore, under the first priority calculation algorithm, the priority of the inspection object group that includes a rotating mechanical element is higher than the priority of the inspection object group that does not include the rotating mechanical element.

[0070] Here, refer to Figure 6 The specific process of calculating the priority using the first priority calculation algorithm as described above will be described with reference to a specific example.

[0071] Figure 6 This is a diagram for explaining a process of calculating a priority using the first priority calculation algorithm. Figure 6 The left side of is a diagram showing an example of mechanical element-control axis correspondence information and each axis subordinate relationship information. Figure 6 The right side of is a diagram showing various parameters calculated by the priority calculation unit 54b under such a configuration.

[0072] exist Figure 6In the example shown on the left side of , the machine tool can move the first mechanical element, the second mechanical element, the third mechanical element, and the fourth mechanical element along the first control axis, the second control axis, the third control axis, the fourth control axis, and the fifth control axis. Figure 6 In the example on the left side of , the first control axis, the third control axis, and the fourth control axis are linear axes, and the second control axis and the fifth control axis are rotation axes. Figure 6 In the example of the axis dependency relationship shown on the left side of , the first to second control axes and the third to fifth control axes can move independently. In addition, the second control axis is lower than the first control axis, the fourth control axis and the fifth control axis are lower than the third control axis, and the fifth control axis is lower than the fourth control axis. Figure 6 In the example of the mechanical element-control axis correspondence information shown on the left side of , the first mechanical element is associated with the first control axis, the second mechanical element is associated with the second control axis, the third mechanical element is associated with the fourth control axis, and the fourth mechanical element is associated with the fifth control axis. Figure 6 , the example in which the axis movement amount of the first control axis is 4, the axis movement amount of the second control axis is 2, the axis movement amount of the third control axis is 3, the axis movement amount of the fourth control axis is 1, and the axis movement amount of the fifth control axis is 3. Figure 6 In the example, the axis movement amount of the linear axis increases in the order of the fourth control axis, the third control axis, and the first control axis, and the axis movement amount of the rotation axis increases in the order of the second control axis and the fifth control axis.

[0073] like Figure 6 As shown, the first mechanical element is associated with the first controlled axis, which is a linear axis; the second mechanical element is associated with the second controlled axis, which is a rotational axis; the third mechanical element is associated with the fourth controlled axis, which is a linear axis; and the fourth mechanical element is associated with the fifth controlled axis, which is a rotational axis. In other words, the second and fourth mechanical elements are rotary mechanical elements associated with the rotational axis, while the first and third mechanical elements are linear mechanical elements associated with the linear axis. Therefore, if the mechanical element sequence for each mechanical element associated with each control axis is calculated in descending order, starting from the control axis that places the rotary mechanical element at a higher position than the linear mechanical element and has the largest axis movement, the fourth mechanical element is ranked first, the second mechanical element is ranked second, the first mechanical element is ranked third, and the third mechanical element is ranked fourth. In addition, if the priority of each inspection object group including each mechanical element is calculated in descending order from the mechanical element with the highest priority, the combination of the second and fourth mechanical elements is one digit, the combination of the first and fourth mechanical elements is two digits, the combination of the third and fourth mechanical elements is three digits, the combination of the first and second mechanical elements is four digits, the combination of the second and third mechanical elements is five digits, and the combination of the first and third mechanical elements is six digits.

[0074] <Second priority calculation algorithm>

[0075] Under the second priority calculation algorithm, the priority calculation unit 54b calculates priorities for multiple inspection object groups based on the axis movement vectors of each control axis sent from the position and posture calculation unit 35. More specifically, the priority calculation unit 54b uses the axis movement vectors calculated for each control axis to calculate the relative axis movement vectors for an axis pair consisting of two of the multiple control axes. Here, if the total number of control axes is M, the total number of axis pairs is M(M-1) / 2. For example, if the axis movement vector of the nth control axis is vn and the axis movement vector of the mth control axis is vm, the relative axis movement vector dnm for the axis pair consisting of the nth and mth control axes is vn-vm.

[0076] Next, the priority calculation unit 54b calculates the relative axis movement amounts (i.e., the norm of the relative axis movement amount vectors) for all axis pairs. The priority calculation unit 54b then calculates the priority of each inspection target group, including combinations of mechanical elements associated with each axis pair via the mechanical element-control axis correspondence information, in descending order, starting with the axis pair with the largest calculated relative axis movement amount. Specifically, under the second priority calculation algorithm, the priority calculation unit 54b determines that there is a high probability of interference occurring in an inspection target group including combinations of mechanical elements associated with axis pairs with large relative axis movement amounts per unit time, and increases the priority of the inspection target group including such combinations of mechanical elements.

[0077] As described above, the dimensionality of the axis movement differs between when the controlled axis is a linear axis and when it is a rotary axis. Therefore, the relative axis movement vector dnm, obtained by subtracting the axis movement vector vm from the axis movement vector vn, loses its physical meaning when at least one of the nth and mth controlled axes is a rotary axis. Therefore, when all controlled axes include rotary axes, the priority of the inspection target group containing the rotating machine elements associated with the rotary axis is calculated using the first priority calculation algorithm described above. However, the priority of the inspection target group containing only linear machine elements is calculated using the second priority calculation algorithm.

[0078] Here, refer to Figure 7 The specific process of calculating the priority using the second priority calculation algorithm as described above will be described with reference to a specific example.

[0079] Figure 7 This is a diagram for explaining a process of calculating a priority using the second priority calculation algorithm. Figure 7 The left side of is a diagram showing an example of mechanical element-control axis correspondence information and each axis subordinate relationship information. Figure 7 The right side of is a diagram showing various parameters calculated by the priority calculation unit 54b under such a configuration.

[0080] exist Figure 7 In the example shown on the left side of , the machine tool can move the first mechanical element, the second mechanical element, and the third mechanical element along the first control axis, the second control axis, the third control axis, and the fourth control axis. Figure 7 In the example on the left side of , the first control axis, the second control axis, the third control axis, and the fourth control axis are all linear axes. Figure 7 In the example of the axis dependency relationship shown on the left side of , the first to second control axes and the third to fourth control axes can move independently. In addition, the second control axis is lower than the first control axis, and the fourth control axis is lower than the third control axis. Figure 7 In the example of the mechanical element-control axis correspondence information illustrated on the left side of , the first mechanical element is associated with the first control axis, the second mechanical element is associated with the second control axis, and the third mechanical element is associated with the fourth control axis.

[0081] exist Figure 7 In the example shown on the left side of , the machine tool has the first to fourth control axes. Therefore, by combining two of the first to fourth control axes, a total of six axis pairs can be formed: the first and second control axes, the first and third control axes, the first and fourth control axes, the second and third control axes, the second and fourth control axes, and the third and fourth control axes. In addition, Figure 7 In the example, the relative axis movement amount between the first control axis and the second control axis is 4, the relative axis movement amount between the first control axis and the third control axis is 5, the relative axis movement amount between the first control axis and the fourth control axis is 3, the relative axis movement amount between the second control axis and the third control axis is 1, the relative axis movement amount between the second control axis and the fourth control axis is 6, and the relative axis movement amount between the third control axis and the fourth control axis is 2. That is, in Figure 7 In the example, the relative axis movement amount increases in the order of the second and third control axes, the third and fourth control axes, the first and fourth control axes, the first and second control axes, the first and third control axes, and the second and fourth control axes.

[0082] like Figure 7As shown, the first and fourth control axes are associated with the combination of the first and third machine elements, the first and second control axes are associated with the combination of the first and second machine elements, and the second and fourth control axes are associated with the combination of the second and third machine elements. Therefore, if the priorities of each inspection target group, including combinations of machine elements associated with each axis pair using machine element-control axis correspondence information, are calculated in descending order from the axis pair with the largest relative axis movement, the combination of the second and third machine elements will be ranked first, the combination of the first and second machine elements will be ranked second, and the combination of the first and third machine elements will be ranked third.

[0083] <Third priority calculation algorithm>

[0084] Under the third priority calculation algorithm, the priority calculation unit 54b calculates priorities for multiple inspection target groups based on the axis movement vectors of each control axis and the pre-movement position vectors of each mechanical element, which are transmitted from the position and posture calculation unit 35. More specifically, the priority calculation unit 54b calculates a reduction rate parameter proportional to the reduction rate of the distance between two mechanical elements constituting each inspection target group based on the axis movement vectors of each control axis, the pre-movement position vectors of each mechanical element, and the mechanical element-control axis correspondence information. The priority for each inspection target group is calculated based on this reduction rate parameter.

[0085] The following describes the process for calculating the reduction rate parameter for each inspection object group. First, the priority calculation unit 54b obtains the axis movement vectors for each control axis sent from the position and posture calculation unit 35. Based on these axis movement vectors, it calculates the velocity vectors of the mechanical elements associated with each control axis via the mechanical element-control axis correspondence information. For linear mechanical elements associated with linear axes, the axis movement vectors are used directly as the velocity vectors. Furthermore, for rotating mechanical elements associated with rotational axes, the outer product of the axis movement vector and a predetermined radial vector is used as the velocity vector. Predetermined radial vectors for each rotational axis are used as radial vectors. More specifically, the radial vectors are oriented in a radial direction orthogonal to the rotational axis, and the norm of the radial vectors is the distance from the rotational axis to the mechanical element along the radial direction.

[0086] Next, the priority calculation unit 54b obtains the pre-movement position vectors of each mechanical element sent from the position and posture calculation unit 35 and calculates the normalized relative position vectors for the two mechanical elements constituting each inspection target group based on these pre-movement position vectors. Here, assuming that the pre-movement position vector of the nth mechanical element is rn and the pre-movement position vector of the mth mechanical element is rm, the normalized relative position vector for the combination of the nth and mth mechanical elements is (rn - rm) / |rn - rm|.

[0087] Next, the priority calculation unit 54b calculates the relative velocity vectors for the two mechanical elements that make up each inspection target group based on the previously calculated velocity vectors for each mechanical element. Here, assuming the velocity vector of the nth mechanical element is vn and the velocity vector of the mth mechanical element is vm, the relative velocity vector for the combination of the nth and mth mechanical elements is vn - vm.

[0088] Next, the priority calculation unit 54b multiplies the previously calculated inner product of the relative velocity vector and relative position vector by a negative sign to calculate a reduction rate parameter for each inspection target group. Here, if the inspection target group consists of the nth and mth mechanical elements, the reduction rate parameter is -(vn-vm)·(rn-rm) / |rn-rm|. The reduction rate parameter calculated through the above process is proportional to the rate of decrease per unit time of the distance between the two mechanical elements. Specifically, if the distance between the two mechanical elements does not change, the reduction rate parameter is 0; if the distance between the two mechanical elements increases, the reduction rate parameter is negative; and if the distance between the two mechanical elements decreases, the reduction rate parameter is positive.

[0089] Next, the priority calculation unit 54b calculates the priorities in descending order, starting with the inspection target group containing the combination of mechanical elements with the highest reduction rate parameter calculated through the above process. Specifically, under the third priority calculation algorithm, the priority calculation unit 54b determines that the likelihood of interference is high in the inspection target group with a high reduction rate of the distance between two components, and increases the priority of the inspection target group containing such a combination of mechanical elements.

[0090] Here, refer to Figure 8 A specific example will be given of a specific process of calculating the priority using the third priority calculation algorithm as described above.

[0091] Figure 8 This is a diagram for explaining a process of calculating a priority using the third priority calculation algorithm. Figure 8 The left side of is a diagram showing an example of mechanical element-control axis correspondence information and each axis subordinate relationship information. Figure 8 The right side of is a diagram showing various parameters calculated by the priority calculation unit 54b under such a structure. Figure 8 The structure of the machine tool shown on the left is Figure 7 The structure is the same as that shown on the left side of , so the detailed description is omitted.

[0092] exist Figure 8In the example, the velocity vector of the first mechanical element associated with the first control axis is set to v1, the velocity vector of the second mechanical element associated with the second control axis is set to v2, the velocity vector of the third mechanical element associated with the fourth control axis is set to v3, the position vector before movement of the first mechanical element is set to r1, the position vector before movement of the second mechanical element is set to r2, and the position vector before movement of the third mechanical element is set to r3. Figure 8 In the example, the relative velocity vector v1-v2 for the combination of the first and second mechanical elements is set to (0, 0, 1), the relative velocity vector v1-v3 for the combination of the first and third mechanical elements is set to (0, 2, 0), the relative velocity vector v2-v3 for the combination of the second and third mechanical elements is set to (1, 0, 0), the normalized relative position vector r1-r2 for the combination of the first and second mechanical elements is set to (0, 0, -1), the normalized relative position vector r1-r3 for the combination of the first and third mechanical elements is set to (0, 0, 1), and the normalized relative position vector r2-r3 for the combination of the second and third mechanical elements is set to (1, 0, 0).

[0093] Therefore, if the reduction rate parameters for each combination of mechanical elements are calculated according to the above process, the reduction rate parameter for the combination of the first and second mechanical elements is 1, the reduction rate parameter for the combination of the first and third mechanical elements is 0, and the reduction rate parameter for the combination of the second and third mechanical elements is -1. Therefore, if the priority is calculated in descending order from the inspection target group containing the combination of mechanical elements with the highest reduction rate parameter, the combination of the first and second mechanical elements is ranked first, the combination of the first and third mechanical elements is ranked second, and the combination of the second and third mechanical elements is ranked third.

[0094] return Figure 1 The priority calculation unit 54b calculates priorities for the multiple inspection target groups extracted by the inspection target group extraction process in the inspection target group extraction unit 54a using any one of the first to third priority calculation algorithms described above, or a combination of these priority calculation algorithms, and adds the calculated priorities to the inspection target group list in the third storage unit 53. In this way, priorities are assigned to the multiple inspection target groups extracted by the inspection target group extraction unit 54a.

[0095] As described above, the interference check assisting device 5 extracts inspection target groups from all combinations of a plurality of mechanical elements based on the axis movement amount vector and the position vector before movement sent from the position and posture calculating unit 35, assigns priorities to these plurality of inspection target groups, and uses a list of the inspection target groups assigned priorities as interference check assisting information (for example, referring to Figure 9 ) is stored in the third storage unit 53.

[0096] The interference check unit 36 ​​obtains the post-movement position vector and post-movement posture information transmitted from the position and posture calculation unit 35 at the interpolation cycle, as well as the interference check auxiliary information stored in the third storage unit 53. Furthermore, the interference check unit 36 ​​performs interference check calculations on a plurality of inspection target groups identified by the obtained interference check auxiliary information, in descending order of priority.

[0097] According to this embodiment, the following effects are obtained.

[0098] The inspection target group extraction unit 54a extracts one or more inspection target groups from all combinations of the multiple mechanical elements constituting the machine tool 2 based on the movement pulses from the numerical controller 3, the mechanical element-control axis correspondence information that associates each control axis in the machine tool 2 with a mechanical element that moves along that control axis among the multiple mechanical elements, and the axis affiliation information that defines the affiliation between the control axes in the machine tool 2. This allows the extraction of inspection target groups by excluding combinations of mechanical elements that clearly do not interfere with each other (for example, combinations of mechanical elements that move together along the control axes based on the movement pulses). Furthermore, the numerical controller 3 moves the multiple mechanical elements along the multiple control axes based on the movement pulses and performs an interference check operation on the inspection target groups extracted by the inspection target group extraction unit 54a. According to this embodiment, the inspection target groups for which the interference check operation is performed can be limited to combinations of mechanical elements that clearly do not interfere with each other. This allows the inspection target groups to be completed in a shorter time than when the numerical controller 3 performs the interference check operation on all combinations.

[0099] The inspection target group extraction unit 54a identifies a control axis that moves in response to a movement pulse as a moving control axis. Based on the mechanical element-control axis correspondence information and the axis dependency information, it classifies the mechanical elements associated with the moving control axis and its subordinate control axes into a subordinate mechanical element group. It also classifies all mechanical elements that do not belong to the subordinate mechanical element group into a stationary mechanical element group. The inspection target group is extracted by combining the mechanical elements belonging to the subordinate mechanical element group with the mechanical elements belonging to the stationary mechanical element group. This allows the inspection target group for interference check calculations to be limited to combinations of mechanical elements that do not interfere with each other and are not noticeable through simple calculations.

[0100] When there are multiple movement control axes, the inspection target group extraction unit 54a extracts the union of the combinations of mechanical elements under each movement control axis as the inspection target group. This allows the inspection target group to be appropriately limited even when mechanical elements are moved simultaneously along multiple control axes.

[0101] The inspection target group extraction unit 54a stores information related to the extracted inspection target group as interference check auxiliary information in the third storage unit 53. The interference check unit 36 ​​performs an interference check operation with reference to the interference check auxiliary information stored in the third storage unit 53. Thus, the inspection target group extraction unit 54a can perform the operation for extracting the inspection target group at a flexible timing independent of the interference check operation performed by the interference check unit 36.

[0102] Furthermore, in this embodiment, an interference check assisting device 5, which has the function of generating interference check auxiliary information, is incorporated into the numerical controller 3 that controls the machine tool 2 and performs interference check calculations. The interference check assisting device 5 generates the interference check auxiliary information based on movement pulses sent from the pulse generating unit 34 of the numerical controller 3. This increases the computational load on the numerical controller 3, but allows the interference check auxiliary information to be generated in real time while the numerical controller 3 controls the machine tool 2. Therefore, even when the machine tool 2 is manually operated by an operator, for example, appropriate interference check auxiliary information can be generated.

[0103] <Second embodiment>

[0104] Next, a numerical control system according to a second embodiment of the present disclosure will be described. In the following description, the same components as those of the numerical control system according to the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof will be omitted.

[0105] Figure 10 This is a schematic diagram of a numerical control system 1A according to this embodiment. As described above, the first embodiment describes a case where the interference check assisting device 5 is incorporated into the numerical controller 3. In contrast, the numerical control system 1A according to this embodiment differs from the numerical control system 1A of the first embodiment in that it includes a numerical controller 3A and an interference check assisting device 5A that is separate from the numerical controller 3A.

[0106] The interference check support device 5A includes a first storage unit 51 , a second storage unit 52 , a check support information generating unit 54 , and a movement position calculating unit 55A.

[0107] The movement amount and position calculation unit 55A reads the numerical control program stored in the machining program memory 31 and, through a process similar to the calculations performed by the command analysis unit 32, interpolation unit 33, pulse generation unit 34, and position and posture calculation unit 35 of the numerical controller 3, generates an axis movement amount vector for each control axis and a pre-movement position vector for each mechanical element at a cycle identical to the interpolation cycle of the numerical controller 3. The movement amount and position calculation unit 55A transmits the generated axis movement amount vector and pre-movement position vector to the inspection support information generation unit 54. The process of generating interference inspection support information in the inspection support information generation unit 54 based on the axis movement amount vector and pre-movement position vector transmitted from the movement amount and position calculation unit 55A is similar to that of the first embodiment, and therefore, a detailed description thereof will be omitted.

[0108] In this embodiment, an interference check assisting device 5A is configured separately from the numerical controller 3A. This interference check assisting device 5A generates interference check assisting information based on the numerical control program stored in the machining program memory 31. This allows interference check assisting information to be generated based on the numerical control program before the numerical controller 3A begins controlling the machine tool 2, more specifically, at the stage where the numerical control program is created. Consequently, the numerical control system 1 of this embodiment can reduce the computational load on the numerical controller 3A when controlling the machine tool 2, compared to the numerical control system 1 of the first embodiment.

[0109] The present disclosure is not limited to the above-described embodiment and is capable of various modifications and variations. For example, in the first embodiment described above, the inspection-support information generator 54 stores the generated inspection-support information in the third storage unit 53, and the interference check unit 36 ​​reads the inspection-support information stored in the third storage unit 53 and performs an interference check operation. However, the present disclosure is not limited to this embodiment. The inspection-support information generated by the inspection-support information generator 54 may also be transmitted to the interference check unit 36 ​​without passing through the third storage unit 53.

[0110] Explanation of symbols

[0111] 1. 1A... numerical control system,

[0112] 2…machine tools,

[0113] 3. 3A... numerical control device,

[0114] 31…Processing program memory,

[0115] 32…Command analysis unit,

[0116] 33…Interpolation unit,

[0117] 34…Pulse generation unit,

[0118] 35…position and posture calculation unit,

[0119] 36…Interference Inspection Department,

[0120] 37…Shape storage unit,

[0121] 5.5A…Interference detection auxiliary device,

[0122] 51 ... a first storage unit,

[0123] 52 ... a second storage unit,

[0124] 53 ... a third storage unit,

[0125] 54…Inspection auxiliary information generation unit,

[0126] 54a ... inspection object group extraction unit,

[0127] 54b ...priority calculation unit,

[0128] 55A: Movement amount position calculation unit.

Claims

1. A numerical control system comprising: a numerical control device that moves a plurality of mechanical elements of a machine tool along a plurality of axes in accordance with movement instructions and performs interference checking calculations between two mechanical elements combined from a predetermined inspection object group; and Interference check assisting means, which assists the interference check operation, It is characterized in that The interference check auxiliary device comprises: a first storage unit storing first information associating each axis in the machine tool with a mechanical element that moves along the axis among the plurality of mechanical elements; a second storage unit storing second information defining a subordinate relationship between the axes in the machine tool; as well as An inspection target group extraction unit extracts one or more inspection target groups by excluding combinations of mechanical elements that clearly do not interfere with each other from all combinations of the plurality of mechanical elements based on the movement command, the first information, and the second information.

2. The numerical control system according to claim 1, characterized in that: The inspection object group extraction unit determines the axis to be moved according to the movement instruction as the movement axis, Based on the first information and the second information, mechanical elements associated with the movable axis and an axis positioned below the movable axis are classified into a subordinate mechanical element group; Classify the mechanical elements that do not belong to the subordinate mechanical element group among all the mechanical elements into a stationary mechanical element group, The inspection object group is extracted by combining the mechanical elements belonging to the dependent mechanical element group and the mechanical elements belonging to the stationary mechanical element group.

3. The numerical control system according to claim 2, characterized in that: When there are a plurality of the movement axes, the inspection object group extraction unit extracts a union of combinations of mechanical elements under each movement axis as the inspection object group.

4. The numerical control system according to any one of claims 1 to 3, characterized in that: The numerical control system further includes a third storage unit that stores information related to the inspection object group extracted by the inspection object group extraction unit. The numerical control device performs the interference check calculation by referring to the information on the inspection target group stored in the third storage unit.

5. The numerical control system according to any one of claims 1 to 3, characterized in that: The second information is stored in the second storage unit in the form of a machine structure tree.

6. An interference check assisting method for assisting an interference check operation in a numerical controller that moves a plurality of mechanical elements of a machine tool along a plurality of axes in accordance with movement instructions and performs an interference check operation between two mechanical elements combined in a check target group. It is characterized in that obtaining the movement command, first information associating each axis of the machine tool with a mechanical element that moves along the axis among the plurality of mechanical elements, and second information defining a subordinate relationship between the axes of the machine tool, Based on the movement command, the first information, and the second information, one or more inspection target groups are extracted by excluding combinations of mechanical elements that clearly do not interfere with each other from all combinations of the plurality of mechanical elements.

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