Machine tool control device, control method and slave axis control device

Abstract

The present invention will improve the followability of the slave axis to the main axis and enhance the synchronization accuracy. The control device comprises: a main axis control unit, which controls the rotation action of the main axis; a slave axis control unit, which controls the feed action of the slave axis; and a numerical control unit, which has a main axis command unit, a slave axis command unit and a first reversal command unit, wherein the main axis command unit outputs a first reversal command to the main axis control unit, and the slave axis command unit outputs a second reversal command that follows the feedback information to the slave axis control unit based on the feedback information from the main axis, and the first reversal command unit outputs a first reversal command to the slave axis control unit before outputting the first reversal command, wherein the slave axis control unit associates the second reversal command and the follow-up result for the second reversal command with the reversal correction amount for storage, and calculates the reversal correction amount for the second reversal command output after the first reversal command is output according to the follow-up result and the reversal correction amount associated with the stored second reversal command determined based on the first reversal command.

Description

Technical Field

[0001] The invention relates to a control device, a control method and a slave axis control device of a machine tool. Background Art

[0002] Patent document 1 describes the following device: in the control of the tapping action in a machine tool using a numerical control device, a feed instruction and a rotation instruction are generated in the numerical control device (hereinafter referred to as the NC device) in coordination with the pitch of the thread to be processed, the rotation amount of the spindle is detected, and the feed motor is driven according to the detected rotation amount.

[0003] Specifically, Patent Document 1 describes a thread processing device, which includes a rotation position detection unit for detecting the rotation position of a spindle and a feed position detection unit for detecting the feed position of a machine, and makes the rotation motor for rotating the spindle and the feed motor for driving the feed synchronously operate to perform a tapping operation. In addition, it is described that the thread processing device includes: a rotation deviation calculation unit, which calculates the rotation deviation between the rotation command value and the detected rotation position of the spindle; a rotation drive unit, which drives the rotation motor according to the rotation deviation; a feed command value calculation unit, which calculates the speed and acceleration of the rotation, and calculates the corresponding feed command value based on the pitch according to the calculated values; a feed correction value calculation unit, which calculates the corresponding feed correction value based on the pitch according to the detected rotation position of the spindle; a feed deviation calculation unit, which calculates the feed deviation between the feed correction value and the detected feed amount of the machine; a correction unit, which corrects the above-mentioned feed command value according to the feed deviation; and a feed drive unit, which drives the feed motor according to the feed command value corrected by the correction unit.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 2629729 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In a control device for a machine tool having an axis structure that performs synchronized operations in a master-slave manner, a delay is likely to occur in a slave axis such as a feed axis following a master axis such as a drive axis, particularly in an acceleration operation immediately after reverse rotation.

[0009] Therefore, in a control device for a machine tool including an axis structure that performs synchronized operation in a master-slave system, it is desired to improve the followability of the slave axis to the master axis and to increase the synchronization accuracy.

[0010] Means for solving problems

[0011] (1) A first aspect of the present disclosure is a control device for a machine tool, the machine tool including a main axis and a slave axis that perform synchronous operations in a master-slave manner, wherein:

[0012] The control device has:

[0013] A spindle control unit, which controls the rotation of the spindle;

[0014] A slave axis control unit, which controls the feeding action of the slave axis;

[0015] A numerical control unit, comprising a main axis command unit, a slave axis command unit and a first reversal command unit, wherein the main axis command unit outputs a first reversal command to the main axis control unit based on a machining program, the slave axis command unit outputs a second reversal command following the feedback information to the slave axis control unit based on the machining program and feedback information from the main axis, and the first reversal command unit outputs a first reversal command to the slave axis control unit before outputting the first reversal command to the main axis control unit.

[0016] The slave axis control unit comprises:

[0017] a storage unit that associates and stores the second reversal instruction, a follow-up result for the second reversal instruction, and a reversal correction amount for the second reversal instruction;

[0018] A reverse correction amount calculation unit calculates a reverse correction amount for the second reverse instruction output after the preceding reverse instruction is output, based on the follow-up result and the reverse correction amount associated with the second reverse instruction determined based on the preceding reverse instruction and stored in the storage unit.

[0019] (2) A second aspect of the present disclosure is a method for controlling a control device of a machine tool, the machine tool including a main axis and a slave axis that perform synchronous operations in a master-slave manner, wherein:

[0020] The control device comprises:

[0021] A spindle control unit, which controls the rotation of the spindle;

[0022] A slave axis control unit, which controls the feeding action of the slave axis;

[0023] a numerical control unit that outputs a first reversal instruction to the spindle control unit based on a machining program, and outputs a second reversal instruction that follows the feedback information to the slave axis control unit based on the machining program and feedback information from the spindle,

[0024] The slave axis control unit stores the second reversal instruction, the follow-up result for the second reversal instruction, and the reversal correction amount for the second reversal instruction in a storage unit in association with each other.

[0025] After the storage unit stores the second reversal instruction, the follow-up result, and the reversal correction amount, the numerical control unit outputs a preceding reversal instruction to the slave axis control unit before outputting the first reversal instruction to the main axis control unit.

[0026] The slave axis control unit obtains a reversal correction amount of the second reversal command output after the preceding reversal command is output, based on the follow-up result and the reversal correction amount associated with the second reversal command determined based on the preceding reversal command and stored in the storage unit.

[0027] (3) A third aspect of the present disclosure is a slave axis control device serving as a slave axis control unit of a control device,

[0028] The control device comprises:

[0029] A spindle control unit that controls the rotation of the spindle of the machine tool;

[0030] A slave axis control unit, which controls the feeding action of the slave axis of the machine tool;

[0031] A numerical control unit, comprising a main axis command unit, a slave axis command unit and a first reversal command unit, wherein the main axis command unit outputs a first reversal command to the main axis control unit based on a machining program, the slave axis command unit outputs a second reversal command following the feedback information to the slave axis control unit based on the machining program and feedback information from the main axis, and the first reversal command unit outputs a first reversal command to the slave axis control unit before outputting the first reversal command to the main axis control unit, wherein:

[0032] The slave axis control device comprises:

[0033] a storage unit that associates and stores the second reversal instruction, a follow-up result for the second reversal instruction, and a reversal correction amount for the second reversal instruction;

[0034] A reverse correction amount calculation unit calculates a reverse correction amount for the second reverse instruction output after the preceding reverse instruction is output, based on the follow-up result and the reverse correction amount associated with the second reverse instruction determined based on the preceding reverse instruction and stored in the storage unit.

[0035] Effects of the Invention

[0036] According to each aspect of the present disclosure, it is possible to improve the followability of the slave axis to the master axis and enhance synchronization accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a block diagram showing a configuration example of a control device for a machine tool according to an embodiment of the present disclosure.

[0038] Figure 2 It is an explanatory diagram showing a tapping operation in thread machining in the Z-axis direction in the present embodiment.

[0039] Figure 3 It is a block diagram showing the configuration of a slave axis control unit in this embodiment.

[0040] Figure 4 This is a flowchart showing a part of the operation of the control device according to the present embodiment.

[0041] Figure 5 This is a flowchart showing a part of the operation of the control device according to the present embodiment. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0043] Figure 1 This is a block diagram showing a configuration example of a control device for a machine tool according to an embodiment of the present disclosure.

[0044] like Figure 1 As shown, the control device 10 of the machine tool includes a computerized numerical control unit (CNC) 100, a spindle control unit 200, and a slave axis control unit 300. The spindle control unit 200 drives the motor 400 of the spindle of the machine tool, and the slave axis control unit 300 drives the motor 500 of the slave axis of the machine tool. In the control device 10, the computer numerical control unit (hereinafter referred to as the CNC unit) 100 controls the spindle control unit 200 and the slave axis control unit 300 based on the machining program, and the spindle control unit 200 and the slave axis control unit 300 respectively drive the motor 400 and the motor 500 to perform machining. The machine tool controlled by the control device 10 is, for example, a 3-axis machining center. The machine tool is not limited to a 3-axis machining center, and may be, for example, a 5-axis machining center. The structure of the machine tool is already known, so in Figure 1 Only the motors 400 and 500 of the machine tool are shown, and other structural components are omitted. The main axis is, for example, a main axis for mounting a tool and rotating it, including a motor. The slave axis is, for example, a tool for processing a workpiece or a feed axis for applying a feed motion to the workpiece, including a motor.

[0045] The numerical control unit includes a CNC unit, and the CNC unit is a numerical control unit that performs numerical control by a computer among the numerical control units.

[0046] In addition, Figure 1 In the figure, only one slave axis control unit 300 and one motor 500 of the control device 10 that perform synchronous actions in a master-slave manner are shown. However, when the machine tool is a three-axis machining center, the feed axes that become slave axes are the X-axis, Y-axis and Z-axis, and the control unit and motor that control the feed axes are respectively arranged on the X-axis, Y-axis and Z-axis.

[0047] In the following description, the control device 10 is described as a device that performs thread machining in synchronized operation by controlling the control device 10 in a master-slave system. Figure 2 1 is an explanatory diagram showing the tapping action in the thread processing in the Z-axis direction. The CNC unit 100 of the control device 10 generates a feed command that becomes a slave axis command so that the spindle 600 equipped with a tapping tool moves to the starting point of the thread processing of the workpiece. In addition, the CNC unit 100 generates a feed command that becomes a slave axis command and a rotation command that becomes a spindle command in accordance with the pitch of the thread in such a manner that the tapping tool installed at the front end of the spindle 600 reaches the bottom of the hole of the thread from the starting point of the thread processing of the workpiece, the feed direction (Z-axis direction) and the rotation direction are reversed, and the tapping tool moves from the bottom of the hole of the thread to the starting point. The control device 10 controls the rotation of the motor 500 of the slave axis based on the slave axis command and the rotation amount of the motor 400 of the spindle that becomes the position feedback information so that the feed amount and rotation amount of the tapping tool at the front end of the spindle 600 do not deviate during the reversal to adjust the feed amount of the tapping tool. In this way, the control device 10 controls the motor 400 synchronously with the motor 500.

[0048] Next, description will be given of the components of the control device 10. In the following description, a case will be described where the spindle 600 does not move in the X-axis direction and the Y-axis direction and the control device 10 performs thread machining in the Z-axis direction.

[0049] <CNC Department>

[0050] like Figure 1 As shown, the CNC unit 100 includes a main axis command unit 101 , a program analysis unit 102 , a synchronization ratio multiplication unit 103 , a slave axis command unit 104 , and a preceding reverse rotation command unit 105 .

[0051] The spindle command unit 101 generates a spindle command for commanding the rotation of the spindle based on the first movement command for commanding the rotation of the spindle output from the program analysis unit 102, and outputs the spindle command to the command calculation unit 201 of the spindle control unit 200. The spindle command includes a reversal command (called a first reversal command), and the reversal command includes the polarity of the rotation direction of the spindle 600 (forward or reverse) and includes information related to the rotation speed and / or acceleration, etc.

[0052] The program analysis unit 102 sequentially reads and analyzes program blocks including data on the rotation of the main shaft and data on the movement of the Z axis based on the machining program (NC data) generated by the CAM (Computer Aided Manufacturing) device. Then, based on the analysis result, the program analysis unit 102 generates a first movement command for commanding the rotation of the main shaft and a second movement command for commanding the movement of the Z axis, which becomes a slave axis, and outputs the first movement command and the second movement command as analysis results to the main shaft command unit 101 and the synchronization ratio multiplication unit 103, respectively.

[0053] Before sending the first movement command to the spindle command unit 101 , the program analysis unit 102 outputs a movement command for instructing the rotation of the spindle during the reverse rotation, which is included in the first movement command for instructing the rotation of the spindle, to the preceding reverse rotation command unit 105 .

[0054] The synchronization ratio multiplication unit 103 multiplies the second movement command by the synchronization ratio and outputs it to the slave axis command unit 104. In the machining of a machine tool, it is sometimes required that the movement of the slave axis follows the movement of the main axis at a ratio other than 1:1. The synchronization ratio multiplication unit 103 multiplies the second movement command by the ratio as a "synchronization ratio". The synchronization ratio is specified by the user in the program, or is specified in advance as a parameter of the CNC unit 100.

[0055] The slave axis instruction unit 104 generates a slave axis instruction for instructing the movement of the Z axis based on the second movement instruction multiplied by the synchronization ratio output from the synchronization ratio multiplication unit 103 and the position feedback information that becomes the position detection amount of the motor 400, and outputs the slave axis instruction to the instruction operation unit 301 of the slave axis control unit 300 of the Z axis. The slave axis instruction includes a reversal instruction (becoming a second reversal instruction), which includes the polarity of the moving direction of the slave axis (forward or reverse), and includes information related to the rotation speed and / or acceleration, etc. By using the position feedback information that becomes the position detection amount of the motor 400 to generate the slave axis instruction, the machine tool can be controlled in a manner that suppresses the deviation between the feed amount and the rotation amount of the tapping tool at the front end of the spindle 600.

[0056] If the advance reversal instruction unit 105 receives a movement instruction for instructing the rotation of the spindle during reversal from the program analysis unit 102, it sends the advance reversal instruction to the slave axis control unit 300. The advance reversal instruction includes the polarity (forward or reverse) of the spindle 600 and includes information related to the rotation speed and / or acceleration. As described above, the program analysis unit 102 outputs the movement instruction for instructing the rotation of the spindle during reversal to the advance reversal instruction unit 105 before sending the first movement instruction to the spindle instruction unit 101. Therefore, the advance reversal instruction unit 105 can output the advance reversal instruction to the slave axis control unit 300 before the spindle instruction unit 101 outputs the spindle instruction including the reversal instruction.

[0057] <Spindle control unit>

[0058] The spindle control unit 200 includes a command calculation unit 201 .

[0059] When the position command is input as the spindle command from the spindle command unit 101 of the CNC unit 100, the command operation unit 201 obtains the difference (position deviation) between the position command and the position feedback information from the motor 400. The command operation unit 201 obtains the speed command based on the obtained position deviation, and obtains the torque command based on the obtained speed command. Furthermore, the command operation unit 201 obtains the current command based on the obtained torque command to control the rotation of the motor 400. The position feedback information is output to the slave axis command unit 104. Since the structure and operation of the command operation unit 201 are already known, the diagram and detailed description of the structure of the command operation unit 201 are omitted.

[0060] <Slave axis control unit>

[0061] The slave axis control unit 300 includes a command operation unit 301, a reverse tracking information output unit 302, a reverse correction amount calculation unit 303, and a storage unit 304. The slave axis control unit 300 serves as a slave axis control device. Figure 3 This is a block diagram showing the structure of the slave axis control unit.

[0062] When the position command is input from the slave axis command unit 104 of the CNC unit 100 as the slave axis command, the command operation unit 301 obtains the difference (position deviation) between the position command and the position feedback information from the motor 500. The command operation unit 301 obtains the speed command based on the obtained position deviation, and obtains the torque command based on the obtained speed command. Furthermore, the command operation unit 301 obtains the current command based on the obtained torque command to control the rotation of the motor 500. Since the structure and operation of the command operation unit 301 are already known, the diagram and detailed description of the structure of the command operation unit 301 are omitted.

[0063] The reversal tracking information output unit 302 obtains the reversal correction amount calculated based on the previous reversal instruction from the reversal correction amount calculation unit 303. In addition, the reversal tracking information output unit 302 obtains the reversal instruction and the position deviation that becomes the reversal tracking result based on the reversal instruction from the instruction calculation unit 301. The reversal tracking information output unit 302 detects the reversal of the polarity of the slave axis instruction input to the instruction calculation unit 301, obtains the reversal time, and can detect information such as the speed and / or acceleration during the reversal.

[0064] Then, the reversal tracking information output unit 302 associates the reversal instruction, the position deviation and the reversal correction amount and stores them in the storage unit 304. The position deviation and the reversal correction amount become the reversal tracking information. As the reversal instruction, information such as speed and acceleration is stored. The reversal tracking result is not limited to the position deviation, and other information such as speed deviation can also be used. The speed deviation is the difference between the speed instruction and the differential value of the position feedback information.

[0065] The storage unit 304 stores a set of information including a past reversal instruction before the preceding reversal instruction is input to the slave axis control unit 300, a reversal correction amount for the past reversal instruction, and a position deviation that is a reversal following result. For example, the storage unit 304 stores n sets of information including a reversal instruction, a reversal correction amount, and a position deviation (n is a natural number).

[0066] like Figure 3 As shown, the reverse correction amount calculation unit 303 includes a reverse instruction comparison unit 3031 and a reverse correction amount adjustment unit 3031 .

[0067] If a prior reversal instruction is received from the prior reversal instruction unit 105, the reversal instruction comparison unit 3031 compares at least one of the information on the speed and acceleration during reversal contained in the prior reversal instruction with at least one of the information on the speed and acceleration of the reversal instruction stored in the storage unit 304 to find the reversal instruction that is closest to the prior reversal instruction.

[0068] Then, the reversal command comparison unit 3031 reads out the position deviation and the reversal correction amount associated with the searched reversal command from the storage unit 304 , and outputs the read-out position deviation and reversal correction amount to the reversal correction amount adjustment unit 3032 .

[0069] The reversal correction amount adjustment unit 3032 determines whether the position deviation is a delayed polarity. If the position deviation is a delayed polarity, the reversal correction amount is adjusted to increase. If the position deviation is an excessive polarity, the reversal correction amount is adjusted to decrease. The adjusted reversal correction amount is output to the instruction operation unit 301 and the reversal tracking information output unit 302. The value of the adjusted reversal correction amount can be determined based on the value of the position deviation, or pre-set to a specified value. The reversal correction amount input to the instruction operation unit 301 is applied to the correction of acceleration or torque in the instruction operation unit 301. The reversal correction amount input to the instruction operation unit 301 can also be applied to the correction of position, position deviation or speed.

[0070] <Main axis and slave axis motors>

[0071] The main axis motor 400 rotates the axis on which the tapping tool is mounted. The slave axis motor 500 moves the tapping tool or the workpiece in the Z-axis direction. The movement in the Z-axis direction may be performed using a rotary motor and a ball screw, or a linear motor.

[0072] In the above, the functional blocks included in the control device 10 have been described.

[0073] In order to realize these functional blocks, the control device 10 has a CPU (Central Processing Unit) and other processing devices. In addition, the control device 10 also has an auxiliary storage device such as a HDD (Hard Disk Drive) for storing various control programs such as application software and OS (Operating System), and a main storage device such as a RAM (Random Access Memory) for storing data temporarily required when the processing device executes the program.

[0074] Furthermore, in the control device 10, the operation processing device reads the application software or OS from the auxiliary storage device, and while expanding the read application software or OS in the main storage device, performs operation processing based on the application software or OS. In addition, based on the operation results, various hardwares equipped in each device are controlled. Thus, the functional blocks of this embodiment are realized. That is, this embodiment can be realized by the cooperation of hardware and software.

[0075] Next, the operation of the control device 10 will be described using a flowchart. Figure 4 and Figure 5 It is a flowchart showing the operation of the control device 10 .

[0076] In step S11, the CNC unit 100 notifies the slave axis control unit 300 of a preceding reverse rotation command. The preceding reverse rotation command includes the polarity (forward or reverse) of the main axis 600 and includes information on the rotation speed and / or acceleration during reverse rotation.

[0077] In step S12, the reverse rotation instruction comparison unit 3031 of the slave axis control unit 300 compares the previous reverse rotation instruction with the stored reverse rotation instruction. The stored reverse rotation instruction includes information such as the speed and / or acceleration when the slave axis is reversed.

[0078] In step S13 , the reversal command comparison unit 3031 reads the position deviation and reversal correction amount associated with the reversal command in which at least one of the speed and acceleration during reversal of the preceding reversal command is identical to or similar to at least one of the speed and acceleration during reversal.

[0079] In step S14 , the inversion correction amount adjustment unit 3032 determines whether there is no positional deviation, whether the positional deviation is of a delayed polarity, or whether the positional deviation is of an excessive polarity.

[0080] When the position deviation is of a delayed polarity, in step S15, the reversal correction amount adjustment unit 3032 adjusts the reversal correction amount by increasing it. When there is no position deviation, in step S16, the reversal correction amount is directly used (without adjusting the reversal correction amount). When the position deviation is of an excessive polarity, in step S17, the reversal correction amount is adjusted by decreasing it.

[0081] In step S18 , the CNC unit 100 notifies the spindle control unit 200 of a reverse rotation command.

[0082] In step S19 , the position feedback of the master axis is input to the slave axis command unit 104 , the reverse rotation operation of the master axis is reflected in the reverse rotation command of the slave axis, and the reverse rotation command is output from the slave axis command unit 104 to the command calculation unit 301 of the slave axis control unit 300 .

[0083] In step S20 , the slave axis control unit 300 applies the reverse rotation correction amount adjusted or not adjusted by the reverse rotation correction amount adjustment unit 3032 in steps S15 to S17 to the reverse rotation operation in the command operation unit 301 .

[0084] In step S21 , the command operation unit 301 of the slave axis control unit 300 controls the motor 500 by applying the reverse correction amount to perform the reverse following operation of the slave axis with respect to the master axis. The reverse following information output unit 302 stores the reverse command, the position deviation resulting from the reverse following operation, and the reverse correction amount.

[0085] According to the above-described embodiment, it is possible to improve the followability of the slave axis to the master axis, particularly the followability of the acceleration operation immediately after the reverse rotation in which the followability of the slave axis is likely to be poor, thereby improving synchronization accuracy.

[0086] The various embodiments of the present invention have been described above, but the control device 10 can realize all or part of its functions through software. However, the functions of the control device 10 can be realized by hardware, or a combination of software and hardware. Here, realization by software means realization by reading and executing a program by a computer. In the case where the control device 10 is composed of hardware, part or all of the various structural parts of the control device 10 can be composed of integrated circuits (ICs) such as LSI (Large Scale Integrated circuit), ASIC (Application Specific Integrated Circuit), gate array, FPGA (Field Programmable Gate Array), etc.

[0087] When the control device 10 is implemented by software, the control device 10 is operated according to the description of Figure 4 as well as Figure 5 The control application stored in the first storage unit such as a hard disk device and ROM for performing the operations shown in the figure stores information required for calculation in the second storage unit such as RAM, and the CPU executes the processing, thereby enabling the operation of the control device 10 to be performed by the program. The control application can be read into the first storage unit such as a hard disk from a computer-readable medium having the program recorded thereon.

[0088] Computer-readable media include various types of tangible storage media. Computer-readable media include non-transitory computer-readable media. Examples of computer-readable media include magnetic recording media (e.g., hard disk drives, etc.), optical magnetic recording media (e.g., optical magnetic disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, semiconductor memories (e.g., mask ROMs, PROMs (Programmable ROMs), EPROMs (Erasable PROMs), flash ROMs, and RAMs (random access memory).

[0089] The above-described embodiments are preferred embodiments of the present invention, but the scope of the present invention is not limited to the above-described embodiments alone, and the present invention can be implemented in various modified forms without departing from the gist of the present invention.

[0090] The control device, the control method, and the slave axis control device disclosed herein include the above-described embodiments and can take various forms of embodiments having the following structures.

[0091] (1) A control device for a machine tool, the machine tool comprising a main axis and a slave axis which perform synchronous operations in a master-slave manner, wherein:

[0092] The control device comprises: a spindle control unit that controls the rotational motion of the spindle;

[0093] A slave axis control unit, which controls the feeding action of the slave axis;

[0094] A numerical control unit, comprising a main axis command unit, a slave axis command unit and a first reversal command unit, wherein the main axis command unit outputs a first reversal command to the main axis control unit based on a machining program, the slave axis command unit outputs a second reversal command following the feedback information to the slave axis control unit based on the machining program and feedback information from the main axis, and the first reversal command unit outputs a first reversal command to the slave axis control unit before outputting the first reversal command to the main axis control unit.

[0095] The slave axis control unit comprises:

[0096] a storage unit that associates and stores the second reversal instruction, a follow-up result for the second reversal instruction, and a reversal correction amount for the second reversal instruction;

[0097] A reverse correction amount calculation unit calculates a reverse correction amount for the second reverse instruction output after the preceding reverse instruction is output, based on the follow-up result and the reverse correction amount associated with the second reverse instruction determined based on the preceding reverse instruction and stored in the storage unit.

[0098] According to this control device, it is possible to improve the followability of the slave axis to the master axis and enhance the synchronization accuracy.

[0099] (2) The control device according to (1) above, wherein the following result is a position deviation that is a difference between a position command output from the slave axis command unit and feedback information from the slave axis.

[0100] (3) The control device according to (1) or (2) above, wherein the reverse correction amount is a correction amount for acceleration or torque.

[0101] (4) A control method for a control device of a machine tool, the machine tool comprising a main axis and a slave axis which perform synchronous motion in a master-slave manner, wherein:

[0102] The control device comprises:

[0103] A spindle control unit, which controls the rotation of the spindle;

[0104] A slave axis control unit, which controls the feeding action of the slave axis;

[0105] a numerical control unit that outputs a first reversal instruction to the spindle control unit based on a machining program, and outputs a second reversal instruction that follows the feedback information to the slave axis control unit based on the machining program and feedback information from the spindle,

[0106] The slave axis control unit associates the second reversal instruction, the follow-up result for the second reversal instruction, and the reversal correction amount for the second reversal instruction and stores them in a storage unit,

[0107] After the storage unit stores the second reversal instruction, the follow-up result, and the reversal correction amount, the numerical control unit outputs a preceding reversal instruction to the slave axis control unit before outputting the first reversal instruction to the main axis control unit.

[0108] The slave axis control unit obtains a reversal correction amount of the second reversal command output after the preceding reversal command is output, based on the follow-up result and the reversal correction amount associated with the second reversal command determined based on the preceding reversal command and stored in the storage unit.

[0109] According to this control method, the followability of the slave axis to the master axis can be improved, thereby increasing synchronization accuracy.

[0110] (5) A slave axis control device serving as a slave axis control unit of a control device,

[0111] The control device comprises:

[0112] A spindle control unit that controls the rotation of the spindle of the machine tool;

[0113] A slave axis control unit, which controls the feeding action of the slave axis of the machine tool;

[0114] A numerical control unit, comprising a main axis command unit, a slave axis command unit and a first reversal command unit, wherein the main axis command unit outputs a first reversal command to the main axis control unit based on a machining program, the slave axis command unit outputs a second reversal command following the feedback information to the slave axis control unit based on the machining program and feedback information from the main axis, and the first reversal command unit outputs a first reversal command to the slave axis control unit before outputting the first reversal command to the main axis control unit, wherein:

[0115] The slave axis control device comprises:

[0116] a storage unit that associates and stores the second reversal instruction, a follow-up result for the second reversal instruction, and a reversal correction amount for the second reversal instruction;

[0117] A reverse correction amount calculation unit calculates a reverse correction amount for the second reverse instruction output after the preceding reverse instruction is output, based on the follow-up result and the reverse correction amount associated with the second reverse instruction determined based on the preceding reverse instruction and stored in the storage unit.

[0118] According to this slave axis control device, it is possible to improve the followability of the slave axis to the master axis and enhance synchronization accuracy.

[0119] Description of Reference Numerals

[0120] 10 Control device

[0121] 100CNC Department

[0122] 101 Spindle command unit

[0123] 102 Program Analysis Department

[0124] 103 Synchronous ratio multiplication unit

[0125] 104 Slave axis command unit

[0126] 105 Pre-reverse command unit

[0127] 200 spindle control unit

[0128] 201 instruction operation unit

[0129] 300 Slave axis control unit

[0130] 301 instruction operation unit

[0131] 302 Reverse follow-up information output unit

[0132] 303 Reverse correction amount calculation unit

[0133] 304 Storage Department

[0134] 400 spindle motor

[0135] 500 from the shaft of the motor.

Claims

1. A control device for a machine tool, the machine tool comprising a main axis and a slave axis which perform synchronous actions in a master-slave manner, characterized in that: The control device has: A spindle control unit, which controls the rotation of the spindle; A slave axis control unit, which controls the feeding action of the slave axis; A numerical control unit, comprising a main axis command unit, a slave axis command unit and a first reversal command unit, wherein the main axis command unit outputs a first reversal command to the main axis control unit based on a machining program, the slave axis command unit outputs a second reversal command following the feedback information to the slave axis control unit based on the machining program and feedback information from the main axis, and the first reversal command unit outputs a first reversal command to the slave axis control unit before outputting the first reversal command to the main axis control unit. The slave axis control unit comprises: a storage unit that associates and stores the second reversal instruction, a follow-up result for the second reversal instruction, and a reversal correction amount for the second reversal instruction; A reverse correction amount calculation unit calculates a reverse correction amount for the second reverse instruction output after the preceding reverse instruction is output, based on the follow-up result and the reverse correction amount associated with the second reverse instruction determined based on the preceding reverse instruction and stored in the storage unit.

2. The control device according to claim 1, characterized in that: The following result is a position deviation which is a difference between a position command output from the slave axis command unit and feedback information from the slave axis.

3. The control device according to claim 1 or 2, characterized in that: The reverse correction amount is a correction amount for acceleration or torque.

4. A control method for a control device of a machine tool, wherein the machine tool comprises a main axis and a slave axis which perform synchronous actions in a master-slave manner, characterized in that: The control device comprises: A spindle control unit, which controls the rotation of the spindle; A slave axis control unit, which controls the feeding action of the slave axis; a numerical control unit that outputs a first reversal instruction to the spindle control unit based on a machining program, and outputs a second reversal instruction that follows the feedback information to the slave axis control unit based on the machining program and feedback information from the spindle, The slave axis control unit associates the second reversal instruction, the follow-up result for the second reversal instruction, and the reversal correction amount for the second reversal instruction and stores them in a storage unit, After the storage unit stores the second reversal instruction, the follow-up result, and the reversal correction amount, the numerical control unit outputs a preceding reversal instruction to the slave axis control unit before outputting the first reversal instruction to the main axis control unit. The slave axis control unit obtains a reversal correction amount of the second reversal command output after the preceding reversal command is output, based on the follow-up result and the reversal correction amount associated with the second reversal command determined based on the preceding reversal command and stored in the storage unit.

5. A slave axis control device, which serves as a slave axis control unit of a control device, The control device comprises: A spindle control unit that controls the rotation of the spindle of the machine tool; A slave axis control unit, which controls the feeding action of the slave axis of the machine tool; A numerical control unit, comprising a main axis command unit, a slave axis command unit and a first reversal command unit, wherein the main axis command unit outputs a first reversal command to the main axis control unit based on a machining program, the slave axis command unit outputs a second reversal command following the feedback information to the slave axis control unit based on the machining program and feedback information from the main axis, and the first reversal command unit outputs a first reversal command to the slave axis control unit before outputting the first reversal command to the main axis control unit. It is characterized in that The slave axis control device comprises: a storage unit that associates and stores the second reversal instruction, a follow-up result for the second reversal instruction, and a reversal correction amount for the second reversal instruction; A reverse correction amount calculation unit calculates a reverse correction amount for the second reverse instruction output after the preceding reverse instruction is output, based on the follow-up result and the reverse correction amount associated with the second reverse instruction determined based on the preceding reverse instruction and stored in the storage unit.

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