JP2854425B2 - Spindle synchronous control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle synchronous control apparatus, and more particularly to a spindle synchronous control apparatus for a machine tool having two spindles for simultaneously performing primary and secondary machining on the same machine. Work transfer control.

[0002]

2. Description of the Related Art FIGS. 3A to 3C are views showing the configuration of a general process-coupled lathe having two main spindles. On the bed 1, a first headstock 2 is provided integrally and a second headstock 3 is provided. The first headstock 2 rotatably supports the first spindle 4, and the second headstock 3 rotatably supports the second spindle 5. Further, a spindle motor 7 is coupled to one end of the first spindle 4 via a belt 6, whereby the torque of the spindle motor 7 is transmitted to the first spindle 4. A built-in spindle motor 8 is directly connected to the second spindle 5, whereby the torque of the spindle motor 8 is transmitted to the second spindle 5. And the first
A chuck 10 for gripping the work 9 is provided at the other end of the main shaft 4, and a chuck 11 for holding the work 9 is similarly provided at the other end of the second main shaft 5. . Here, FIG. 3A is a view showing that the work 9 is gripped by the chuck 10 of the first spindle 4 and is in a state during the first step, and FIG. FIG. 3C shows a state in which the main spindles approach each other and grip each other in order to transfer the workpiece 9 to the chuck 11 of the second main spindle 5, and FIG. FIG. 9 is a view showing that the delivery of the first step is completed and the second step is being performed.

FIG. 4 is a block diagram showing a configuration of a conventional control device for controlling a process-coupled lathe. This control device is used when a work transfer mode from a first spindle 4 to a second spindle 5 is started. The first and second spindle drive units 13 and 14 have a rotational position command value generation unit 12 that issues the same rotational position command value CONθ.
Is connected to a spindle motor 7 for driving the first spindle 4. An encoder 15 as first position detecting means for detecting the rotational position of the spindle motor 7 is connected to the main shaft motor 7, and an encoder 16 for detecting the rotational position is connected to the first main shaft 4. Similarly, the second spindle drive 1
A spindle motor 8 for driving the second spindle 5 is connected to 4, and an encoder 17 is connected to the spindle motor 8 as second position detecting means for detecting the rotational position of the spindle motor 8.
Since the second spindle side is a built-in motor type spindle, no slippage occurs, so only the encoder 17 is required.

The first spindle drive unit 13 calculates a differential value of the rotational position command value CONθ with respect to time to obtain a speed feedforward amount VCON, a rotational feedforward amount calculating unit 18, a rotational position command value CONθ and a current rotational position. A position deviation calculator 19 for calculating the difference DIFFθ1 from APAθ1, a position loop gain setting unit 20 for multiplying the position deviation DIFFθ1 by the position loop gain Kp, and a speed feedforward amount VCON and an output Vθ1 of the position loop gain setting unit 20. a speed command value calculating section 21 for obtaining sum and the velocity command value V ^* bets, a speed control unit 22 for speed control of the spindle motor 7 in accordance with the speed command value V ^*, the signal from the first main shaft 4 which is fed back from the encoder 16 A spindle position detector 23 for detecting the current position APAθ1 of the And a motor position detecting section 24 for detecting the current position of the motor from the signal fed back from da 15. In addition, the second spindle drive device 14 has the same configuration as the first spindle drive device except that the second spindle is a built-in motor type spindle and thus has one position detection unit. Since the two spindle devices perform the speed feedforward control as described above, when the position control is performed in response to the position command from the position command value generator 12, the command position CONθ and the current position are always determined. Deviation of APAθ1, APAθ2 DIFFθ1, DIFF
θ2 is both zero, so that the synchronized state is always maintained.

In the conventional control device shown in FIG. 4 described above, when the work is transferred from the first spindle to the second spindle, the position command value generating section issues the same position command to each drive device, Each of the received driving devices is performed on the premise that the first and second spindles are accurately controlled in position and synchronized with the same position.

[0006]

However, in the conventional control device shown in FIG. 4, if an error occurs in speed control due to any cause (for example, a speed ratio error due to an error in the diameter of a pulley, etc.), the position deviation becomes zero. The command position deviates from the current position. As a result, the first spindle and the second spindle have different current positions, and a synchronization error occurs. When a synchronization error occurs, not only does an error occur between the processing position in the first step and the processing position in the second step, but also when the two spindles grip each other to transfer the work (FIG. 3). see (b)), there is a possibility that the current position regenerative energy processing circuit of the main shaft of the person who is leading from the command position is within the spindle drive and is always regenerative state is destroyed by overheating.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem.
An object of the present invention is to provide a control device in which a synchronization error does not occur by automatically generating a command value in consideration of a speed control error.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides first and second spindles and a first spindle for driving the spindles.
A second spindle drive device, a rotation position command generation unit that issues the same rotation position command to both the first and second spindle drive devices, a first position detection unit that detects the current position of the first spindle, A second position detecting means for detecting a current position of the two spindles, a speed feedforward amount calculating unit provided in the spindle drive device for obtaining a differential value of a rotational position command with respect to time for speed feedforward control, and a rotational position. The command position from the command generation unit and the first position detecting means or the second position
By adding the current value obtained by multiplying the position loop gain to the difference between the position from the position detecting means and said speed feedforward quantity by dividing the resulting value by the velocity feed forward amount, spindle mechanical system And a speed feedforward amount corrector that corrects the speed feedforward amount based on the speed error rate. Things.

Before entering the mode for synchronizing the first and second spindles with the correction value of the speed feedforward amount, a position command having a constant speed component is supplied from the rotational position command generator to the first spindle drive. To the second spindle drive,
The calculation may be performed after confirming that each drive device is performing position control at a constant speed.

Further, when the workpiece is transferred from one spindle to the other spindle, the speed feedforward amount is corrected so that the difference between the commanded position and the current position becomes smaller than a predetermined value. It is good to check after confirming.

[0011]

In the above construction , the spindle is driven by the spindle drive unit, the same rotation position command is issued to both the first and second spindle drive units by the rotation position command generation unit, and the rotation position is controlled for speed feedforward control. The differential value of the command with respect to time is obtained by the speed feedforward amount calculation unit.
You. Then, the speed error rate calculating unit, the difference in the current position from the commanded position and the first position detection means or the second position detecting means
A value obtained by multiplying the position loop gain, by adding said speed feedforward amount, by dividing the resulting value by the velocity feed forward amount, the error rate of the overall speed control including a spindle mechanical system the calculated, the speed feedforward amount correction unit, intends row correction by velocity error rate relative to the speed feedforward amount. This
Ri, eliminating the positional deviation between the second spindle, perform accurate synchronous control, regenerative control circuit is prevented from being over-thermal destruction fallen constantly regeneration mode.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. The same parts as those in FIG. 4 described above are denoted by the same reference numerals, and description thereof will be omitted. FIG. 1 is a block diagram showing a configuration of a spindle synchronization control device according to the present invention. In the first spindle drive device 25, a speed command value V ^* output from the speed command value calculation unit 21, an output from the motor position detection unit 24, and a speed feedforward amount VCON as an output from the speed feedforward amount calculation unit 18 are provided. And a speed control error rate calculation unit 27 that calculates an error rate of speed control from the speed control error rate calculation unit 27. The speed control error rate calculation unit 27 includes a speed feedforward amount VCO output from the speed feedforward amount calculation unit 18.
A multiplier 28 as a speed feedforward amount correction unit for multiplying N by the error rate of the speed control is connected. Similarly, in the second spindle drive device 26, the speed command value V ^* output from the speed command value calculation section 21 and the spindle position detection section 23
A speed control error rate calculation unit 27 that calculates an error rate of speed control from the output of the speed feedforward amount calculation unit 18 and the output of the speed feedforward amount calculation unit 18 is provided. Is connected to a multiplier 28 for multiplying the speed feedforward amount VCON, which is the output of the speed feedforward amount calculation unit 18, by an error rate of speed control.

Next, a method of calculating an error rate of the speed control and a method of correcting the speed feedforward amount will be described. The error rate α of the speed control is obtained by setting the speed feed forward amount to VCON, the command position to CONθ, and the current position to APAθ.
1. If the position loop gain is Kp, it is calculated by the following equation.

Α = A / B... 100 A = VCON + (CONθ−APAθ1) Kp B = VCON Generally, the response of the speed control unit 22 causes a change in the speed component of the position command value such as during acceleration / deceleration. Since a position deviation occurs during a certain transition, the above-described calculation of the speed control error rate α is performed by using the speed command value V ^* and the mode as described above.
It is necessary to refer to the output of the data position detection unit 24 and perform the operation in a steady state where the speed component of the position command value does not change.

Next, the operation of this embodiment will be described with reference to a control step.
I will explain later . When the synchronous control mode is commanded (step S1), first, the rotational position command generator 12 generates a position command value having a constant speed component (step S2), and the first spindle driving device responds to this position command value. The second spindle drive device 25 and the second spindle drive device 26 confirm from the signals from the encoders 15, 16, 17 whether or not the respective spindles 4, 5 are in a steady state in which a constant speed is maintained (step S3). Then, when each of the spindles 4 and 5 enters a steady state in which the spindles maintain a constant speed, the speed control error rate calculator 27 outputs the speed command value V ^* output from the speed command value calculator 21 and the spindle position detector 23.
Then, the error rate of the speed control is calculated from the output of the speed feedforward amount calculation unit 18 and the output of the speed feedforward amount calculation unit 18 (step S4). Then, the multiplier 28 corrects the speed feedforward amount by multiplying the speed control error rate α by the speed feedforward amount VCON output from the speed feedforward amount calculation unit 18 (step S5). Further, as a result of correcting the speed feedforward amount using the speed control error rate α obtained by the above-mentioned equation (100), it is determined whether or not the position deviation has actually become zero (step S6). If it is determined that the work 9 has been completed, the workpiece 9 is gripped by the chuck 11 on the second spindle 5 side (see FIG. 3) (step S7). If it is determined in step S6 that the position deviation is not zero, the process returns to step S1.

[0016]

As described above, according to the present invention, the same rotational position command is issued to both of the two spindle drive devices by the rotational position command generator, and the time of the rotational position command is controlled for speed feedforward control. determined by the speed feedforward amount calculating unit a differential value for, the speed error rate calculating unit, and the command position and the value obtained by multiplying the position loop gain to the difference in the current position, by adding the said speed feedforward amount, as a result By dividing the obtained value by the speed feedforward amount, the error rate of the entire speed control including the spindle mechanical system is obtained, and the speed feedforward amount correction unit corrects the speed feedforward amount by the speed error rate. The system is configured to perform this operation even if an error occurs in speed control for some reason and a position deviation occurs. It is possible to dynamically calculate and correct the current position between the first main spindle and the second main spindle to perform synchronous control with high accuracy, and to prevent damage to the regenerative control circuit due to one of the main spindles being constantly in the regenerative mode. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a spindle synchronization control device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating the operation of the present embodiment.

FIG. 3 is a diagram illustrating the operation of the present embodiment.

FIG. 4 is a block diagram showing an example configuration of a conventional spindle synchronization control device.

[Explanation of symbols]

 2 First headstock 3 Second headstock 12 Rotational position command value generator 15 Encoder 17 Encoder 18 Speed feedforward amount calculator 25 First spindle drive 26 Second spindle drive 27 Speed control error rate calculator 28 Multiplier

Claims (3)

(57) [Claims] A first and a second spindle; and a first and a second spindle drive for driving the first and the second spindles. A synchronous position control device having a function of synchronously controlling the rotational positions of the first and second spindle drive units; a rotational position command generating unit for issuing the same rotational position command to both the first and second spindle drive units; and detecting a current position of the first spindle. A first position detecting means, a second position detecting means for detecting a current position of the second spindle, and a speed feed for determining a differential value of a rotational position command with respect to time for speed feed forward control provided in the spindle drive device. and forward amount calculating section, and a value obtained by multiplying the Pojishi <br/> Yonrupugein the difference between the current position from the commanded position and the first position detection means or the second position detecting means from the rotation position command generating unit, the rate By adding the feedforward quantity by dividing the resulting value by the velocity feed forward amount, a speed error rate calculating unit for obtaining an error rate of the overall speed control including a spindle mechanical system, the speed feedforward And a speed feedforward amount correction unit for correcting the amount by the speed error rate. 2. A method according to claim 1, wherein the rotational position command generation unit issues a position command having a constant speed component to the first spindle drive before entering the mode for synchronizing the first and second spindles with the correction value of the speed feedforward amount. Device, to the second spindle drive,
2. The spindle synchronization control device according to claim 1, wherein the calculation is performed after confirming that each drive device is performing position control at a constant speed. 3. The transfer of a workpiece from one spindle to the other spindle is performed by correcting the speed feedforward amount so that the difference between the commanded position and the current position becomes equal to or less than a predetermined value. 2. The spindle synchronization control device according to claim 1, wherein the control is performed after confirmation.