JP2002326140A - Multiple spindle synchronizing control system and multiple spindle synchronizing control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multiple spindle synchronizing control system and a multiple spindle synchronizing control method that can prevent breakage of a machining tool and a workpiece by reducing a synchronization error in a driven spindle. SOLUTION: The multiple spindle synchronizing control system, which is used in a multiple spindle machine tool wherein as a main spindle 111 as a reference of synchronous control on a plurality of spindles is accelerated, a plurality of driven spindles 112 to 11N and 13 are accelerated to follow the main spindle 111, detects respective positions of the main spindle 111 and the driven spindles 112 to 11N and 13, then according to the detection result, detects such a spindle out of the main spindle 111 and the driven spindles 112 to 11N and 13 as is relatively slower than the other spindles to or beyond a given tolerance, and controls the spindles other than the slower spindle to a constant speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multi-axis synchronization control device and a multi-axis synchronization control method.

[0002]

2. Description of the Related Art In recent years, numerical control machine tools used for drilling holes such as taps and drills employ a method of synchronizing and controlling a machining axis on which a tap bit or a drill bit is mounted and a feed axis for sending the same. Used. By synchronizing the feed speed of the feed shaft, that is, the rotation speed of the motor driving the feed shaft, with respect to one machining axis, machining with a machining speed higher than machining without synchronization can be performed. .

Further, when tapping or drilling holes from the same direction on the same surface of a workpiece, it is possible to improve the production efficiency by driving a large number of processing axes at a time to perform the processing. it can. For example, there is a type in which tapping and drilling are performed at the same time by the number of axes of the multi-axis head using a machine tool using a multi-axis gear head.

In a numerically controlled machine tool having a large number of machining axes and feed axes as described above, one of the machining axes is used as a main spindle serving as a synchronization reference, and the other machining axes and feed axes are synchronized with the main spindle. It is common to use a slave axis that follows. As described above, a technique for providing a master-slave relationship between one machining axis, another machining axis, and a feed axis is disclosed in, for example, Japanese Patent Application Laid-Open No. 11-30 / 1999.
No. 5839.

[0005]

However, in the numerically controlled machine tool as described above, the speed of machining can be increased by synchronous control, but the motor used for the machining axis has a high resolution because of the high-speed rotation specification. Has to be lowered, so that the control in the low-speed rotation range becomes unstable. Generally, in drilling and tapping,
The work exerts a load on the motor, and particularly when the motor starts moving from a stopped state, the effect of the load is greatest, so that the controllability is further deteriorated and unstable.

In particular, in multi-axis tapping in which a large number of female threads are cut at once using a large number of machining axes, after the female thread is cut, the machining axis is rotated in a direction opposite to the direction of tapping to form a tap bit. Is extracted from the workpiece, but the controllability is most unstable at this time.

[0007] Because when the tap bit is pulled out of the workpiece, the tap bit enters the workpiece and is in the most contact state, so that the load exerted on the machining axis by the workpiece is the largest, and further, the machining axis is removed. This is because the machining axis is once stopped to rotate in the opposite direction to the direction of the tap machining, and then the machining axis is rotated again, so that the machining axis must be controlled in a low-speed rotation range where controllability is poor. Therefore, as a result of the unstable controllability, an error between the actual position of the slave axis and a theoretical position that should be present for the slave axis to follow the master axis corresponding to the position of the master axis (hereinafter referred to as a synchronization error). Will also be the largest.

In the numerically controlled machine tool described above, one of a number of machining axes is determined as the main axis, and only the main axis is made to follow the main axis. Therefore, other than the main axis due to damage or poor hardness of the workpiece. Even when the rotation speed of the machining axis significantly decreases, the state is not detected, and synchronization of machining axes other than the main spindle cannot be guaranteed, which may lead to breakage of a machining tool or a workpiece.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a multi-axis synchronization control device and a multi-axis synchronization control device capable of reducing a synchronization error of a slave shaft and preventing breakage of a machining tool and a workpiece. The purpose is to provide a control method.

[0010]

The above object of the present invention is achieved by the following means.

(1) The multi-axis synchronous control device according to the present invention
A main axis serving as a reference for synchronous control of the plurality of axes, a plurality of sub-axes following the main axis, main axis acceleration control means for accelerating the main axis, and accelerating the plurality of sub-axes so as to respectively follow the main axis. Slave axis acceleration control means, and position detection means for detecting the positions of the main shaft and the slave shaft, respectively.
A delayed axis detecting means for detecting an axis relatively delayed from the other axis by a predetermined allowable range or more than the other axes based on a detection result by the position detecting means; A constant speed control means for controlling a shaft to a constant speed irrespective of acceleration control by the main axis acceleration control means and the slave axis acceleration control means.

(2) When the delayed axis is the main axis, the constant speed control means controls the slave axis, which has advanced relative to the main axis by more than the predetermined allowable range, at a constant speed, When the delayed axis is the slave axis, the main axis and the slave axes other than the delayed axis are controlled at a constant speed.

(3) When the error exceeds a predetermined allowable limit range, the apparatus further comprises stopping means for stopping all of the main shaft and the plurality of slave shafts.

(4) The multi-axis synchronous control method according to the present invention
In a multi-axis synchronous control method of accelerating a plurality of slave axes by following the master axis while accelerating the master axis, a step of detecting the positions of the master axis and the slave axes, respectively, Detecting an axis that is relatively delayed from the other axis by a predetermined tolerance range or more than the other axis, and controlling an axis other than the delayed axis from an accelerated state to a constant speed based on the detected axis; And characterized in that:

(5) In the step of controlling at a constant speed, when the delayed axis is the main axis, the slave axis, which has advanced more than the predetermined allowable range relative to the main axis, is controlled at a constant speed. When the delayed axis is a slave axis, the main axis and the slave axes other than the delayed axis are controlled at a constant speed.

(6) The method further comprises the step of stopping all of the main shaft and the plurality of slave shafts when the error exceeds a predetermined allowable limit range.

[0017]

According to the first aspect of the present invention, an axis which is relatively delayed from the other axis by a predetermined allowable range or more than the other axis is detected, and the axis other than the delayed axis is controlled by the main axis acceleration control. Since the control is performed at a constant speed regardless of the acceleration control by the means and the slave axis acceleration control means, the delay of the relatively delayed axis can be within an allowable range, and the main axis due to the large delay,
Breakage of the slave shaft and the workpiece can be prevented, and the working efficiency can be maintained.

Further, according to the present invention, since the accelerating main shaft and the subordinate shaft can be synchronized, for example, after a female thread is cut on a workpiece by a processing tool attached to each shaft, each shaft is temporarily stopped. Can be applied when the machining tool is removed from the workpiece by rotating each axis in the reverse direction to the thread cutting, and the situation where synchronization of the master axis and slave axis is the most difficult, that is, stop It is necessary to control in the low-speed rotation range in order to accelerate each axis, and furthermore, in the situation where the load from the workpiece is the highest in order to extract the attached processing tool from the workpiece, Axis synchronization can be performed.

According to the second aspect of the present invention, when the delayed axis is the main axis, the slave axis that is advanced relative to the main axis by a predetermined allowable range or more is controlled at a constant speed. The other slave axes follow the main axis and accelerate together with the main axis, so that a relative delay of the main axis can be prevented, and the main axis, the slave axis, and the workpiece can be prevented from being damaged. Also, the working efficiency can be maintained. When the delayed axis is a slave axis, the main axis and the slave axes other than the delayed axis are controlled at a constant speed, so that only the delayed axis follows the main axis and accelerates, so that the delayed Relative delay can be prevented, the main shaft, the sub shaft, and the workpiece can be prevented from being damaged, and the working efficiency can be maintained.

According to a third aspect of the present invention, when the error exceeds a predetermined allowable limit range, the main shaft and the plurality of sub-axes are all stopped, so that even if the speed is controlled at a constant speed, the delay of the shaft becomes large. In such a case, it is possible to prevent the main shaft, the sub shaft, the workpiece, and the like from being damaged.

According to a fourth aspect of the present invention, the main shaft and the slave shaft detect an axis relatively delayed from the other axis by a predetermined allowable range or more, and determine an axis other than the delayed axis as main axis acceleration control means. Since the speed is controlled at a constant speed irrespective of the acceleration control by the slave axis acceleration control means, the delay of the relatively delayed axis can be kept within the allowable range, and the main axis, the slave axis, and the work We can prevent damage such as things,
Work efficiency can also be maintained.

Further, according to the present invention, since the main axis and the sub-axis which are accelerating can be synchronized with each other, for example, after the female thread is cut on the workpiece by a processing tool attached to each axis, the respective axes are temporarily set. Can be applied when the machining tool is removed from the workpiece by rotating each axis in the reverse direction to the thread cutting, and the situation where synchronization of the master axis and slave axis is the most difficult, that is, stop It is necessary to control in the low-speed rotation range in order to accelerate each axis, and furthermore, in the situation where the load from the workpiece is the highest in order to extract the attached processing tool from the workpiece, Axis synchronization can be performed.

According to a fifth aspect of the present invention, when the delayed axis is the main axis, the slave axis which is advanced relative to the main axis by a predetermined allowable range or more is controlled at a constant speed. The other slave axes follow the main axis and accelerate together with the main axis, thereby preventing the relative delay of the main axis.
Breakage of the slave shaft and the workpiece can be prevented, and the working efficiency can be maintained. Also,
When the delayed axis is a slave axis, the main axis and the slave axes other than the delayed axis are controlled at a constant speed, so that only the delayed axis follows the main axis and accelerates, so that the relative position of the delayed slave axis is increased. It is possible to prevent any delay and prevent damage to the main shaft, the sub shaft, the workpiece, and the like, and to maintain the working efficiency.

According to a sixth aspect of the present invention, when the error exceeds a predetermined allowable limit range, all of the main shaft and the plurality of sub-axes are stopped, so that even if the speed is controlled at a constant speed, the delay of the shaft becomes large. In such a case, it is possible to prevent the main shaft, the sub shaft, the workpiece, and the like from being damaged.

[0025]

Embodiments of the present invention will be described below with reference to the drawings.

The present invention is applied when the rotation speed is accelerated by an operation command from the state where each axis of the multi-axis machine tool is stopped. In particular, when a female thread is cut into a workpiece by a processing tool attached to each axis, then once each axis is stopped, then each axis is rotated in the reverse direction of threading to remove the processing tool from the workpiece. It is suitable. Therefore, in the following description, control when each axis is accelerated to a predetermined rotation speed will be described.

FIG. 1 is a schematic configuration diagram of a multi-axis machine tool to which the present invention is applied, and FIG. 2 is a block diagram for explaining a function of a controller for synchronously controlling each axis of the machine tool.

The multi-axis machine tool 10 includes a plurality of machining axes 11
A machining axis amplifier 12 for independently controlling the speed of the machining axis 11; a feed axis 13 for moving the plurality of machining axes 11 in the same direction at once; and a feed axis amplifier for controlling the speed of the feed axis 13 14 Machining axis amplifier 12
And feed axis amplifier 14 are both processing axis 11 and feed axis 13
Are connected to a controller 15 for performing synchronous control of. In FIG. 1, the plurality of machining axes 11 are
The processing axis 111, the second processing axis 112 to the N-th processing axis 11N are shown.

Each of the machining shafts 11 is rotated by an independently rotating motor, and an encoder (not shown) for detecting the number of rotations of the motor is provided. These processing axes 11 are for performing tapping processing on the same surface of the workpiece 100 in the same direction.

The machining axis amplifier 12 supplies electric power to the motor based on a command value given from the controller 15.

The feed shaft 13 is for moving the movable table 16 holding the processing shaft 11 in the direction of the workpiece 100, and includes a feed shaft motor 17 and a ball screw 18 rotated by the motor 17. Ball screw 18
Engages with a gear groove (not shown) formed in the bottom portion of the movable base 16 and rotates the ball screw 18 so that the movable base 16 moves forward or backward in the work direction. The feed shaft motor 17 is provided with an encoder (not shown), and the number of rotations of the motor 17 is detected.

The feed axis amplifier 14 supplies electric power to the feed axis motor 17 based on a command value given from the controller 15.

The controller 15 outputs command values to the machining axis amplifier 12 and the feed axis amplifier 14, respectively. The specific internal configuration of the controller 15 is shown in FIG.

In the following description, a plurality of machining axes 11
The first machining axis 111 is the main axis among 1-11N, and the second
A description will be given assuming that the machining shaft 112 to the N-th machining shaft 11N and the feed shaft 13 are slave axes. Also, as shown in FIG. 2, the processing shaft amplifiers 12 shown in FIG. 1 are provided for the number of the processing shafts 11 from the first amplifier 121 to the Nth amplifier 12N, and the first motors 201 to 201 connected to each of them. The speed of the Nth motor 20N is controlled. The first motor 201 to the Nth motor 20N rotate the first processing shaft 111 to the Nth processing shaft 11N, respectively.

As shown in FIG. 2, the controller 15
First target position calculation unit 21, first speed calculation unit 22, speed control unit 23, second target position calculation unit 242 to Nth target position calculation unit 24N, second speed calculation unit 252 to Nth speed Calculation unit 25N, second speed control unit 262 to N-th speed control unit 26N, feed axis target position calculation unit 27, feed axis speed calculation unit 28, feed axis speed control unit 29, synchronization error monitoring unit 30 It is comprised including.

The first target position calculator 21 is configured to control the first machining axis 1
Information on the target position of the movement of the tool 11 is input from an input device (not shown), and the amount of movement of the first machining axis 111, for example, the amount of movement (lead) for one rotation of the machining tool attached to the first machining axis 111. , The number of rotations of the first machining shaft 111 required to move to the target position is calculated.

The first speed calculator 22 calculates the amount of movement of the first machining axis 111 per unit time with respect to the workpiece 100 based on the input amount of movement, and calculates the rotation speed command value of the first machining axis 111. Then, the data is output to the first speed control unit 23.

The first speed control unit 23 outputs the rotation speed command value output from the first speed calculation unit 22 to the first amplifier 121 as it is when there is no instruction of a constant speed from a synchronization error monitoring unit 30 described later. If there is a constant speed instruction from the synchronization error monitoring unit 30, the rotation speed command value output from the first speed calculation unit 22 when the constant speed instruction is given is output to the first amplifier 121. I do.

The first motor 201 is provided with an encoder, and information on the number of revolutions of the first motor 201 is fed back to the first speed calculator 22 via the first amplifier 121. The first speed calculator 22 calculates the rotation speed based on the fed-back rotation speed, compares the rotation speed with the speed command value, and performs feedback control so that the calculated rotation speed becomes the speed command value.

The information on the number of revolutions of the first motor 201 is not only output to the first speed calculator 22, but also the synchronization error monitor 30 and the second target position calculator 242 to the Nth target position calculator. Also output to 24N.

The second target position calculating section 242 to the N-th target position calculating section 24N store in advance the information of the lead of the machining tool attached to the first machining axis 111, and input the information of the lead and the information from the encoder. First motor 2
The movement amount of the first machining axis 111 is calculated based on the information of the number of rotations of 01.

If the movement amount of the first machining axis 111 matches the movement amount of the second machining axis 112 to the N-th machining axis 11N, all the machining axes 11 are synchronized. Therefore, the second target position calculator 242 to the Nth target position calculator 2
4N is a target theoretical position for moving the second machining axis 112 to the N-th machining axis 11N by the same amount as the calculated movement amount of the first machining axis 111, that is, the first machining axis 11
The position at which the second processing axis 112 to the N-th processing axis 11N have moved by one movement amount is calculated.

Second speed calculator 252 to Nth speed calculator 2
5N is based on the theoretical positions calculated by the second target position calculator 242 to the Nth target position calculator 24N, respectively.
The rotation speed command values of the second machining axis 112 to the N-th machining axis 11N are calculated, and the second speed control unit 262 to the N-th speed control unit 26 are calculated.
Output to N.

Second speed control unit 262 to Nth speed control unit 2
6N, the rotation speed command values output from the second speed calculation unit 252 to the Nth speed calculation unit 25N are used as they are, when there is no instruction of the constant speed from the synchronization error monitoring unit 30 described later. The second speed calculator 252 to the N-th speed calculator 25N output the signal to the amplifier 12N, and when there is a constant speed instruction from the synchronization error monitoring unit 30, when the constant speed instruction is given. The rotation speed command value is set to the second amplifier 1
22 to the Nth amplifier 12N.

The second motor 202 to the Nth motor 20
N is provided with an encoder, and the second motor 20
Information on the rotation speeds of the second to Nth motors 20N is fed back to the second speed calculator 252 to the Nth speed calculator 25N via the second amplifier 122 to the Nth amplifier 12N, respectively. The second speed calculation unit 252 to the Nth speed calculation unit 25N
The rotation speed is calculated based on the fed-back rotation speed, compared with the speed command value, and feedback control is performed so that the calculated rotation speed becomes the speed command value.

The second motor 202 to the Nth motor 20
The information on the number of rotations of N is stored in the second speed calculators 252 to 252, respectively.
It is output not only to the Nth speed calculation unit 25N but also to the synchronization error monitoring unit 30.

The feed axis target position calculation unit 27 is, like the second target position calculation unit 242 to the Nth target position calculation unit 24N,
The information of the lead of the machining tool attached to the first machining axis 111 is stored in advance, and the information of the lead and the information of the rotation speed of the first motor 201 input from the encoder is used to determine the first machining axis 111. Calculate the movement amount. Then, in order to synchronize the feed shaft 13 with the first machining axis 111, the position where the first machining axis 111 has moved by the moving amount is set as a theoretical position that is the target of the movement of the feed axis 13.

The feed shaft speed calculator 28 calculates the rotation speed command value of the feed shaft 13 based on the theoretical position calculated by the feed shaft target position calculator 27, and sends it to the feed shaft speed controller 29.
Output to

The feed axis speed controller 29 outputs the rotation speed command value output from the feed axis speed calculator 28 to the feed axis amplifier 14 as it is when there is no instruction of a constant speed from a synchronous error monitor 30 described later. However, when there is a constant speed instruction from the synchronization error monitoring unit 30, the rotation speed command value output from the feed shaft speed calculation unit 28 when the constant speed instruction is first given is transmitted to the feed shaft amplifier 14. Output to

The synchronization error monitoring unit 30 determines the amount of movement of the first machining shaft 111 based on information on the number of rotations of the first motor 201 from the encoder provided for each motor, and the second machining corresponding to the amount of movement. The theoretical positions of the shaft 112 to the Nth machining axis 11N and the theoretical position of the feed shaft 13 are calculated. First
The calculation of the amount of movement of the machining axis 111 and the theoretical positions of the second machining axis 112 to the N-th machining axis 11N and the feed shaft 13 is performed by the above-described first target position calculation unit 242 to Nth target position calculation unit 24N.
Since it is the same as that of the feed axis target position calculator 27, the description is omitted.

Further, the synchronization error monitoring unit 30 performs the second machining shaft 112 to the N-th machining shaft 11N and the feed shaft 13 based on the information on the rotation speeds of the second motor 202 to the N-th motor 20N and the feed shaft motor 17. Is calculated. In calculating the current position, information on the lead of the machining tool attached to each machining axis and information on the lead of the ball screw 18 of the feed shaft 13 are used. These pieces of information are stored in the synchronization error monitoring unit 30 in advance. I have.

Then, the synchronization error monitoring unit 30 compares the theoretical position and the current position of each of the second machining axis 112 to the N-th machining axis 11N and the feed axis 13, and compares the theoretical position with the current position. It is checked how much is delayed or advanced, and the error is calculated as a synchronization error. Note that the theoretical position is a position when the slave axis moves by the same amount of movement with respect to the movement amount of the main shaft, and therefore, the error between the movement amount of the main shaft and the movement amount of the slave axis is equal to the synchronization error.

If the synchronization error is within a predetermined allowable range for all the slave axes, the synchronization error monitoring unit 30 continues monitoring. However, for example, the current position of the second machining axis 112 is advanced from the theoretical position (the first machining axis 1).
When the synchronization error exceeds the allowable range, the second speed control unit 262 of the second processing shaft 112 that has exceeded the allowable range has a constant speed. Output instructions. The second speed control unit 262 to which the constant speed instruction is input stores the rotation speed command value output from the second speed calculation unit 252 at that time, and the synchronization error monitoring unit 30 stops outputting the constant speed instruction. Until the rotation speed command value is stored, the same rotation speed command value is output so that the second motor 202 rotates at a constant speed in accordance with the stored rotation speed command value. The other slave shafts are synchronized with the main shaft and accelerated together with the main shaft.

For example, the current position of the second machining axis 112 is delayed from the theoretical position (the first machining axis 1).
When the synchronization error exceeds the allowable range, the first speed control unit 23 of the first processing axis 111 (spindle) and the allowable range are set. A constant speed instruction is output to the third speed control units 263 to N-th speed control units 26N and the feed shaft speed control unit 29 of the slave axes (the third processing shaft 113 to the N-th processing shaft 11N and the feed shaft 13) which have not exceeded. . The first speed control unit 23, the third speed control unit 263 to the Nth speed control unit 26 to which the constant speed instruction has been input.
N and the feed axis speed control unit 29 respectively output the rotation speed command output from the first calculation unit 22, the third speed calculation unit 253 to the N-th speed calculation unit 25N, and the feed axis speed calculation unit 28 at that time. The first motor 201, the third motor 203 to the Nth motor 20N, and the rotation of the feed shaft 17 are rotated according to the stored rotation speed command value until the synchronization error monitoring unit 30 stops outputting the constant speed instruction. The same rotation speed command value is output so as to be constant. For the slave axis whose synchronization error exceeds the allowable range, acceleration is performed as it is so as to synchronize with the advanced spindle.

The above-mentioned predetermined allowable range is a value calculated in advance by an experiment or the like, and is a value determined so as not to cause a problem in the main shaft, the slave shaft, and the workpiece. Therefore, a highly reliable value can be arbitrarily applied to the allowable range.

As described above, the synchronization error monitoring unit 30 can keep a relatively slow axis ahead of a fast axis by setting a relatively fast axis at a constant speed. Then, the synchronization error monitoring unit 30 outputs a constant speed instruction until the delay of the relatively delayed axis falls within the allowable range. Specifically, description will be given with reference to FIG.

FIG. 3 is a diagram showing the relationship between the time and the speed of the relatively advanced axis and the lagging axis. In FIG. 3, the moving amount of the first machining axis 111 (spindle), that is, the moving distance of the second machining axis 112 (slave axis) is shorter than the moving distance of the first machining axis 111, The description will be made on the assumption that the two machining shafts 112 are delayed from the theoretical position by an allowable range or more. In addition, minor axes other than the second machining axis 112 are omitted in FIG.

In FIG. 3, the response according to the rotation command value of the first machining axis 111 is indicated by a dotted line A. Actually, the response is slightly delayed from the rotation command value, so that the actual response of the first machining axis 111 is as shown by the dashed line B. Then, the response of the second machining axis 112 whose movement has been delayed due to the load of the workpiece is represented by a solid line C.
Indicated by Further, the response of the first machining axis 111 controlled at a constant speed for the delayed second machining axis 112 is indicated by a thick line D.

In FIG. 3, the first machining axis 11 up to time T1 is shown.
The moving distance of 1 is represented by the area of the triangle abc, and the moving distance of the second machining axis 112 is represented by the area of the triangle dbe.
Therefore, the difference in the moving distance between the first machining axis 111 and the second machining axis 112 is represented by the area indicated by the diagonal line excluding the area of the triangle abc from the area of the triangle dbe.
Here, since the area of the range shown by the oblique lines is equal to or larger than the predetermined allowable range, an error (synchronization error) between the delayed movement distance of the second machining axis 112 and the advanced movement distance of the first machining axis 111 is obtained.
Is controlled so that the first machining axis 111 is kept at a constant speed.

Then, the first machining axis 111 until time T2
Is represented by the area of the trapezoid afgh, and the movement distance of the second machining axis 112 is represented by the area of the triangle dfh. Here, the error between the area of the trapezoid afgh and the area of the triangle dfh falls within a predetermined allowable value, that is, the second machining axis 11
Since the synchronization error between the second machining axis 111 and the first machining axis 111 has fallen within a predetermined allowable range, the control for keeping the first machining axis 111 at a constant speed is ended, and the first machining axis 111 returns to the original rotation command value. Accelerated to respond.

As described above, the synchronization error monitoring unit 30 calculates the moving distance from the relationship between the speed and time of each axis, determines whether the movement is delayed or advanced, and determines when the synchronization error exceeds the allowable range. Then, output a constant speed instruction to the axis that is traveling,
When the synchronization error falls within the allowable range, the output of the constant speed instruction can be stopped.

Next, the operation of the multi-axis machine tool to which the present invention is applied will be described.

FIG. 4 is a flowchart showing the flow of the operation of the multi-axis machine tool to which the present invention is applied.

First, information on the target position is input to a first target position calculating section 21 for controlling the first processing axis 111 as the main spindle, and the first processing is performed based on the rotational speed command value calculated based on the information. The shaft 111 is rotated (Step S401). Then, the second processing shaft 112 to the N-th processing shaft 11N and the feed shaft 13 which are the slave axes are rotated by the rotation speed command value calculated so as to be synchronized with the rotation of the first processing shaft 111 (step S402). ).

Here, after the multi-axis machine tool finishes tapping, the synchronous error monitoring unit 30 stops each axis once, then rotates each axis in reverse to the time of threading, and removes the processing tool from the workpiece. It is determined whether or not each axis is being accelerated for the tap return operation (step S4).
03). If the tap return operation is not being performed and each axis is not being accelerated (step S403: NO), it is determined whether the machining is completed (step S404). If the machining is completed (step S404: YES), , End the operation. If the processing has not been completed (step S40)
(4: NO) returns to step S401 and operates to synchronize each axis until the machining is completed.

If the tap return operation is being performed and each axis is being accelerated (step S403: YES), the synchronization error monitoring unit 30 monitors the synchronization error between the master axis and the slave axis (step S405). Then, it is determined for each slave axis whether or not a synchronization error between the movement amount of the second machining axis 112 to the Nth machining axis 11N and the movement amount of the feed shaft 13 with respect to the movement amount of the first machining axis 111 is within a predetermined allowable range. (Step S40
6) If the synchronization errors of all the slave axes are within the allowable range (step S406: YES), the process proceeds to step S404.

If there is a minor axis whose synchronization error is not within the allowable range (step S406: NO), the minor axis (the moving amount of the second machining axis 112 to the N-th machining axis 11N and the feed axis 13) is not within the allowable range. Whether any one of the minor axes) is delayed with respect to the first machining axis 111, that is, whether or not the movement amount of the minor axis that is not within the allowable range is smaller than the movement amount of the first machining axis 111. A determination is made (step S407).

If the slave axis that is not within the allowable range is not delayed (advanced) (step S407: NO), the advanced slave axis is controlled at a constant speed (step S408), and then the synchronization error is reduced to a predetermined allowable value. It is determined whether it is within the range (step S410).

On the other hand, if the slave axis that is not within the allowable range is delayed (step S407: YES), the first machining axis 11
1, and the other slave axes other than the slave axes not within the allowable range are controlled at a constant speed (step S409), and thereafter, it is determined whether or not the synchronization error is within a predetermined allowable range (step S410).

If the synchronization error falls within the predetermined allowable range (step S410: YES), the control of the axis controlled at the constant speed is returned to the control responding to the original rotation speed command value (step S411). It returns to the process of S401.

If the synchronization error is not within the predetermined allowable range (step S410: NO), it is determined whether the synchronization error has exceeded the allowable limit range (step S412). Here, the allowable limit range is a boundary value at which there is a risk that the main axis, the sub-axis, the workpiece, and the like may be damaged due to an excessively large synchronization error of the sub-axis. Value.

If the synchronization error exceeds the allowable limit (step S412: NO), there is a risk of breakage of the main shaft, the slave shaft, the workpiece, etc.
The movement amount of the machining axis 112 to the N-th machining axis 11N and all the axes of the feed axis 13 are stopped (step S413). When the synchronization error does not exceed the allowable limit (step S41)
2: YES), and return to the process of step S406.

As described above, in the multi-axis machine tool to which the present invention is applied, of the main axis and the sub-axis, the axis relatively delayed from the other axis by a predetermined allowable range or more is detected, and the axis other than the delayed axis is detected. Since the axis is controlled at a constant speed regardless of the acceleration control by the main axis acceleration control means and the auxiliary axis acceleration control means, the delay of the relatively delayed axis can be within an allowable range, and the main axis due to the increased delay , The slave shaft, the workpiece, and the like can be prevented from being damaged, and the working efficiency can be maintained.

Further, according to the present invention, since the accelerating main shaft and the subordinate shaft can be synchronized, for example, after a female thread is cut on a workpiece by a processing tool attached to each shaft, each shaft is temporarily stopped. Can be applied when the machining tool is removed from the workpiece by rotating each axis in the reverse direction to the thread cutting, and the situation where synchronization of the master axis and slave axis is the most difficult, that is, stop It is necessary to control in the low-speed rotation range in order to accelerate each axis, and furthermore, in the situation where the load from the workpiece is the highest in order to extract the attached processing tool from the workpiece, Axis synchronization can be performed.

More specifically, when the delayed axis is the main axis, the slave axis which is advanced relative to the main axis by a predetermined allowable range or more is controlled at a constant speed. By following the main shaft and accelerating with the main shaft, it is possible to prevent a relative delay of the main shaft, prevent the main shaft, the slave shaft, and the workpiece from being damaged, and further,
Work efficiency can also be maintained. When the delayed axis is a slave axis, the main axis and the slave axes other than the delayed axis are controlled at a constant speed, so that only the delayed axis follows the main axis and accelerates, so that the delayed Relative delay can be prevented, the main shaft, the sub shaft, and the workpiece can be prevented from being damaged, and the working efficiency can be maintained.

Further, when the synchronization error of the slave shaft exceeds a predetermined allowable limit range, all of the main shaft and the slave shaft are stopped. , The main shaft, the sub shaft, and the workpiece can be prevented from being damaged.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a multi-axis machine tool to which the present invention is applied.

FIG. 2 is a block diagram for explaining a function of a controller that synchronously controls each axis of a machine tool to which the present invention is applied.

FIG. 3 is a diagram illustrating a relationship between time and speed of a relatively advanced axis and a lagging axis.

FIG. 4 is a flowchart showing a flow of an operation of the multi-axis machine tool to which the present invention is applied.

[Description of Signs] 10 Multi-axis machine tool 11, 111-11N Machining axis 12, 121-12N Machining axis amplifier 14 Feed axis amplifier 15 Controller 17 Feed axis motor 201-20N Motor 21 First target position calculation unit 22 First speed Calculation unit 23 First speed control unit 242 to 24N Second to Nth target position calculation unit 252 to 25N Second to Nth speed calculation unit 262 to 26N Second to Nth speed control unit 27 Feed axis target position calculation unit 28 Feed axis speed calculator 29 Feed axis speed controller 30 Synchronization error monitor

Claims (6)

[Claims] 1. A main axis serving as a reference for synchronous control of a plurality of axes; a plurality of sub-axes following the main axis; main axis acceleration control means for accelerating the main axis; Minor axis acceleration control means for accelerating so as to follow; position detecting means for respectively detecting the positions of the main axis and the minor axis; and other one of the main axis and the minor axis based on the detection result by the position detecting means. Delay axis detecting means for detecting an axis relatively delayed by more than a predetermined allowable range from the axis of the axis, regardless of the acceleration control by the main axis acceleration control means and the slave axis acceleration control means for axes other than the delayed axis A multi-axis synchronous control device, comprising: constant speed control means for controlling at a constant speed. 2. The constant speed control means, wherein, when the delayed axis is the main axis, the constant speed control means controls the slave axis, which is advanced with respect to the main axis by more than the predetermined allowable range, at a constant speed, and 2. The multi-axis synchronous control device according to claim 1, wherein when the set axis is a slave axis, the slave axes other than the main axis and the delayed axis are controlled at a constant speed. 3. 3. The apparatus according to claim 1, further comprising a stop unit configured to stop all of the main shaft and the plurality of slave shafts when the error exceeds a predetermined allowable limit range. Multi-axis synchronous control device. 4. A multi-axis synchronous control method for accelerating a plurality of slave axes while following a main axis while accelerating a main axis, wherein: a step of detecting the positions of the main axis and the slave axes, respectively; A step of detecting, based on the position of the slave axis, an axis that is relatively delayed from the other axis by a predetermined allowable range or more than the other axes, and that an axis other than the delayed axis is kept constant from an accelerated state. A multi-axis synchronous control method, comprising the steps of: 5. In the step of controlling at a constant speed, when the delayed axis is the main axis, the sub-axis, which is advanced with respect to the main axis by more than the predetermined allowable range, is controlled at a constant speed,
The multi-axis synchronous control method according to claim 4, wherein when the delayed axis is a slave axis, the main axis and the slave axes other than the delayed axis are controlled at a constant speed. 6. The method according to claim 4, further comprising a step of stopping all of the main shaft and the plurality of sub-axes when the error exceeds a predetermined allowable limit range. Axis synchronous control method.