JP2010022145A - Synchronous control apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synchronous control apparatus which advances a phase to cancel a phase delay included in a main state-quantity feedback value without increasing high-frequency noise components to ensure that a state-quantity of a subordinate control subject to precisely follows a state quantity of a main control subject without oscillation or delay even if the exact present main state-quantity cannot be obtained. <P>SOLUTION: The synchronous control apparatus includes a main controller which generates a main operation quantity so that the main state quantity matches a main state quantity instruction, a subordinate state quantity instruction generator which generates a subordinate state quantity instruction so that the main state quantity synchronizes with a subordinate state quantity, and a subordinate controller which generates a subordinate operation quantity so that the subordinate state quantity matches the subordinate state quantity instruction. The subordinate state quantity instruction generator has a compensation calculator (11) which generates a phase-advanced main state quantity advanced in phase relative to the main state quantity, based on the main operation quantity and the main state quantity, and an instruction change unit (15) which changes the phase-advanced main state quantity to the subordinate state quantity instruction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a synchronous control device that controls a state quantity of a main control target and a state quantity of a sub control target in synchronization.

  A conventional synchronous control device usually gives a command synchronized with the main controller and the sub-controller, or controls the sub-control target using the feedback of the main state quantity as a command. However, in the former method, there is a problem that the main state quantity and the subordinate state quantity shift due to the difference in dynamic characteristics between the main control object and the sub control object. In the latter method, information on the main state quantity is detected. There is a problem that the amount of follow-up is delayed because there is a delay until the controller can be used. To solve this problem, for example, in a synchronous control device for a motor, a foreseeing controller that is controlled so that the rotational position of the motor predicted from the dynamic characteristic model of the driven motor matches the future target position command, and the spindle motor A predictor that inputs a target position command value and a spindle motor position, calculates a predicted value of the future position of the spindle motor at multiple times, and outputs the predicted value to the converter. In some cases, the future target position command value of the dependent axis motor at a plurality of times corresponding to the predicted value of the future position of the spindle motor at a plurality of times is obtained based on the predicted value and used as the future target position command value of the prediction controller. (For example, refer to Patent Document 1). In other words, by using the predictor to determine the future position of the spindle motor, the follower motor can be used for predictive control, and the predictive controller that reflects the model of the slave shaft motor enables accurate synchronous control with no tracking delay. . In another motor synchronous control device, among the two causes of follow-up delay occurring between the spindle motor position and the slave motor position, a multiplier and an adder are used for the data transfer time delay in the data transfer means. For the response delay in the slave drive controller, the corrected spindle position is used as a position command and the corrected spindle speed and The problem is solved by generating a current command by feeding forward acceleration. There are some (see, for example, Patent Document 2). Since this uses only the feedback value of the spindle motor, it is substantially equivalent to creating a slave motor position command by performing a filtering process including phase advance on the feedback value of the spindle motor. In addition, by estimating the amount of state with advanced phase using an observer, a single control target controller compensates for the delay contained between the state amount command and state amount feedback, and sets the control loop gain high. A technique that can be used is known (see, for example, Patent Document 3). However, no conventional method has been devised to use this technique for synchronous control of a plurality of controlled objects.

  FIG. 4 shows a conventional motor synchronous control apparatus configured to give a command synchronized with the main controller and the slave controller. In FIG. 4, reference numeral 71 denotes a main controller, which generates a spindle torque command so that the position command and the spindle motor position coincide. As the calculation contents of the main controller 71, generally two-degree-of-freedom control combining feedback control such as PID control and feedforward control is often used. Reference numeral 72 denotes a spindle motor, which rotates with current controlled so as to generate thrust according to the spindle torque command. The spindle motor position is detected by a sensor such as an encoder and fed back to the main controller 71. A slave controller 73 generates a torque command so that the position command and the slave motor position coincide with each other. In the prior art, the spindle motor position and the slave motor position are synchronized by giving a position command synchronized with the spindle and the slave shaft. Reference numeral 74 denotes a slave motor, which rotates with current controlled so as to generate a thrust according to the slave torque command. The slave motor position is detected by a sensor such as an encoder and fed back to the slave controller 73.

  Next, FIG. 5 shows a conventional motor synchronous control apparatus configured to give position feedback of the main controller as a command of the slave controller. In FIG. 5, 71 is a main controller, 72 is a main shaft motor, and 74 is a sub shaft motor, which are the same as those in FIG. A slave controller 73 generates a slave torque command so that the spindle motor position feedback matches the slave motor position. In this prior art, the spindle motor position feedback is given as a slave shaft position command, and the spindle motor position and slave motor position are synchronized by setting the control gain of the slave motor high. However, as described above, if the spindle motor position feedback is used as the slave motor position command in this configuration as it is, the delay until the spindle motor position information is detected and can be used in the slave controller, or the slave control delay. Therefore, there is a problem that the follower motor position is delayed. In order to improve this problem, in Patent Document 2, the sub-controller 73 is as shown in FIG. In FIG. 6, reference numeral 73 denotes a slave controller, which corresponds to the slave controller 73 of FIG. In FIG. 6, the output of the slave controller 73 is a current command, but the current command and the torque command are in a proportional relationship and may be regarded as equivalent. A differentiator 78 differentiates the spindle motor position to calculate the spindle motor speed. A differentiator 79 differentiates the spindle motor speed to calculate the spindle motor acceleration. 82 is a J / Kt multiplication, which calculates the current feed forward by multiplying the spindle motor acceleration and inertia and dividing by the torque constant. Reference numeral 81 denotes Td multiplication, which multiplies the spindle motor acceleration by a constant. A correction speed obtained by adding this value to the spindle motor speed is feed-forwarded. Reference numeral 80 denotes Td multiplication, which multiplies the correction speed by a constant. A correction position obtained by adding this value to the spindle motor position is used as a position control command value. A position controller 83 generates a feedback speed command from the deviation between the correction position and the driven shaft motor position. In general, P control or PI control is often used. A differentiator 85 calculates a slave motor speed from the slave motor position. A speed controller 84 generates a feedback current command from the deviation between the sum of the correction speed and the feedback speed command and the slave motor speed. In general, P control and PI control are often used. The sum of the feedback current command and the current feed forward is the current command. In normal synchronous control, the spindle motor speed is directly used as speed feedforward. However, this conventional technology uses the product of the spindle motor acceleration and a constant Td as a speed feedforward. Yes. Further, in normal synchronous control, the spindle motor position is used as the position command of the slave controller as it is, but this prior art advances the phase a little by adding the product of the correction speed and the constant Td to this. The effect of advancing these phases cancels the delay until the spindle motor position information is detected and becomes usable by the slave controller and the slave control delay, thereby improving the synchronization accuracy.

  FIG. 7 shows the configuration of Patent Document 2 using predictive control. In FIG. 7, 71 is a master controller, 72 is a spindle motor, 73 is a slave controller, and 74 is a slave motor, which are the same as those in FIG. A predictor 75 calculates a predicted future position of the spindle motor using the position command and the spindle motor position feedback. A converter 76 converts the predicted future position value of the spindle motor into the future target position of the slave motor. A preview controller 77 generates a follower motor position command so that the predicted future position of the follower motor matches the future target position of the follower motor. This prior art improves synchronization accuracy by predicting the future position of the spindle motor using the position command and the spindle motor position.

As described above, the conventional synchronous control device gives the main state quantity command and the subordinate state quantity command in synchronization, generates the subordinate state quantity command by using the feedback of the main state quantity as it is or by performing the filtering process. A subordinate amount command is generated using a state amount command and feedback, and none of the main operation amounts are used in calculating the subordinate amount command.
Japanese Patent No. 3551328 (page 4, FIG. 1) Japanese Patent Laying-Open No. 2006-252392 (page 13, FIGS. 1 to 4) Japanese Patent No. 3804601 (5th page, FIG. 1)

In the conventional synchronous control device, the main operation amount, which should be useful information when making the subordinate state command, is discarded without being used, and the following problems occur.
For example, the method shown in FIG. 4 has a problem that the position of the motor shifts due to a difference in dynamic characteristics between the spindle motor 72 and the driven motor 74. In addition, the slave controller only gives a position command and cannot obtain spindle motor position information. Therefore, if the spindle position does not follow the position command due to disturbances, the slave shaft cannot follow it. There's a problem.
Further, in the method shown in FIG. 5, there is a delay until the spindle motor position information is detected and the slave controller can be used, and the slave shaft control delay. Therefore, the phase of the slave motor position is changed to the spindle motor position. There is a problem of being late.
Further, in the method of Patent Document 1 shown in FIG. 6, although the phase delay is improved, it is included in the spindle motor feedback because the phase advance filtering process including the differential element is included in the feedback value of the spindle motor. There is a problem that high frequency components due to generated noise and resolution increase, the torque command of the driven shaft fluctuates violently at high frequency, and vibrations are generated or a large-capacity current amplifier is required.
Further, in the method of the conventional patent document 2 shown in FIG. 7, since the future position command of the spindle is necessary for predicting the future position of the spindle, the application is limited when such a command is obtained. was there.
The present invention has been made in view of such problems, and even if a future state quantity command of the main control target is not obtained, the state quantity of the sub control target is accurately controlled without vibration or delay. An object of the present invention is to provide a synchronous control device that can be controlled to follow the state quantity.

In order to solve the above problems, the present invention is configured as follows.
According to the first aspect of the present invention, a main controller that generates a main operation amount so that a main state quantity of a main control target matches a main state quantity command, and the main state quantity and the sub-state quantity are synchronized. Synchronous control comprising: a slave state quantity command generator that generates a slave state quantity command; and a slave controller that generates a slave operation quantity so that the slave state quantity of the slave control object matches the slave state quantity command. In the apparatus, the slave state amount command generator generates the slave state amount command based on the main operation amount and the main state amount.
According to a second aspect of the present invention, in the synchronous control device according to the first aspect, the sub-state command generator generates a phase whose phase is more advanced than the main state based on the main operation amount and the main state amount. A phase lead compensation computing unit for generating a lead main state quantity and a command converter for converting the phase lead main state quantity into the slave state quantity command are provided.
According to a third aspect of the present invention, in the synchronous control device according to the second aspect, the phase lead compensation computing unit is a phase lead compensation observer.
According to a fourth aspect of the present invention, in the synchronous control device according to the third aspect, the phase advance compensation observer includes a control target model that generates the phase advance main state quantity from a main operation quantity, and the phase advance main state quantity. A delay model for generating a main state quantity estimated value by delaying, an observer gain for generating a main manipulated variable correction value from a difference between the main state quantity and the main state quantity estimated value, and the main manipulated variable correction value from the main manipulated variable And a subtractor that generates a new main operation amount by subtracting.
The invention according to claim 5 is the synchronous control device according to claim 4, wherein the delay model includes a dead time.
The invention according to claim 6 is the synchronous control device according to claim 4, wherein the delay model includes a low-pass filter.
According to a seventh aspect of the present invention, in the synchronous control device according to the fifth aspect, the dead time of the delay model is a parameter that can be changed by an operator, and the phase advance main state quantity is changed by changing the dead time parameter. The phase is adjusted.
According to an eighth aspect of the present invention, in the synchronous control device according to the sixth aspect, the cutoff frequency of the low-pass filter of the delay model is a parameter that can be changed by an operator, and the cutoff frequency parameter of the low-pass filter is changed. To adjust the phase of the phase lead main state quantity.
The invention according to claim 9 is the synchronization control device according to claim 5, further comprising a delay time adjuster for adjusting the dead time so that the slave state quantity falls within a predetermined synchronization range of the master state quantity. And
The invention according to claim 10 is the synchronization control device according to claim 6, further comprising a delay time adjuster for adjusting the cutoff frequency of the low-pass filter so that the slave state quantity falls within a predetermined synchronization range of the main state quantity. It is characterized by comprising.
The invention according to claim 11 is the synchronous control device according to claim 1, wherein the main control object and the sub control object are motors, and the main operation amount and the sub operation amount are commands proportional to acceleration. The main state quantity and the sub-state quantity are positions.
According to a twelfth aspect of the present invention, in the synchronous control device according to the fourth aspect, the controlled object model is a motor model and outputs a value proportional to the second-order integral of the input. .

  According to the first to twelfth aspects of the present invention, when generating the command of the secondary state quantity, not only the feedback of the main state quantity or the command but also the information included in the main operation quantity is used, so that more detailed main control Since the target information can be given to the slave controller, the phase can be advanced to cancel the phase lag included in the feedback value of the main state quantity without increasing the high frequency noise component. Even if an accurate main state quantity cannot be obtained, it is possible to provide a synchronous control device that can control the state quantity of the sub-control target by accurately following the state quantity of the main control target without vibration or delay.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of the synchronous control device of the present invention. In FIG. 1, 1 is a main controller, 2 is a main control object, 3 is a sub controller, 4 is a sub control object, and 5 is a sub state quantity command calculator. As described above, in the prior art, the subordinate state command is calculated only from the main state amount, or the subordinate state command is calculated from the main state amount and the main state amount command. Throw away without using the amount. The slave state amount command calculator 5 generates a slave state amount command using the main operation amount and the main state amount. By using the main operation amount, the main state amount can be predicted by the simulator from the main control target model, and further, the observer can be configured by using the main state amount.

  FIG. 2 shows an example in which the present invention is applied to a motor synchronous control device. In FIG. 2, 11 is a phase advance compensation calculator, 12 is a spindle motor model, 13 is a delay model, 14 is an observer gain, 15 is a command converter, and 16 is a delay time adjuster. It is an Example at the time of using a phase advance compensation observer as the subordinate state quantity instruction | command calculator 5 of FIG. The phase advance compensation calculator 11 can be configured by an observer, and calculates a slave motor position command that is a slave state amount command by using a spindle acceleration command that is a master operation amount and a spindle motor position that is a master state amount. Yes. Although the spindle acceleration command is used for input, since acceleration, torque, and current are in a proportional relationship, they can be easily converted by multiplication / division of a proportional constant, so that a torque command or current command may be used. The spindle motor model 12 is a physical model that represents the spindle motor 6. However, it is the rest excluding the delay element. The delay model 13 is a model of a delay element removed from the spindle motor 12, and is represented by a primary delay or dead time. The spindle motor model 12 and the delay model 13 can be regarded as a simulator for calculating the spindle motor position from the spindle torque command, and the output thereof is the estimated spindle motor position. The observer gain 14 multiplies the error between the spindle motor position and the spindle motor position estimated value by the observer gain to create an observer feedback. By appropriately setting the observer gain, the estimated value of the observer converges. A normal observer uses the spindle motor position estimate for feedback, whereas a phase advance compensation observer uses the output of the spindle motor model 12. As a result, the spindle motor position whose phase is advanced by the delay model 13 can be extracted. The command converter 15 converts the phase advance main shaft motor position into a slave motor position command. In this conversion, for example, the input is output as it is when you want the spindle motor and the slave motor to perform exactly the same operation, and the input is a constant when you want the slave motor to operate by multiplying the movement distance of the spindle motor by a constant. The operation may be a multiplication, and may be a function such as a polynomial in some cases. The operation content of the slave controller 3 may be, for example, two-degree-of-freedom control in which feedback control such as PID control and feedforward control are combined as in the general prior art. The conventional phase advance compensation observer feeds back the amount of state advanced in phase so that the gain of the control system can be set high. In the present invention, the synchronization accuracy between the main shaft and the slave shaft is improved by applying the phase advance compensation observer to the synchronous control device.

  FIG. 3 is a block diagram showing details of the spindle motor model 12 and the delay model 13 of the phase advance compensation observer 11. In the figure, s represents a Laplace operator. The spindle motor model 12 is a physical model of the spindle motor without delay. An acceleration disturbance d is added to the acceleration command u, and if integrated, the velocity v is obtained, and further integrated, the position x is obtained. The delay model 13 is a dead time of time T. When the user adjusts the dead time T as a parameter, the phase advance amount of the phase advance main state quantity can be adjusted. Further, as shown in FIG. 2, the delay time adjuster 16 can be provided to adjust the delay time online, and the synchronization error can be kept within a predetermined value.

The control system shown in FIGS. 2 and 3 is discretized and programmed into a computer, the observer gain is set appropriately to converge the observer state quantity estimate, and the spindle motor phase advance position estimate in FIG. If used as a command for the shaft motor, the main shaft and the slave shaft can be controlled in synchronization with high accuracy.
The present invention is different from the prior art in that the main operation amount is used when calculating the command value of the subordinate state quantity, and that the phase advance compensation observer is configured for the main control target, and the main state quantity having the advanced phase. The phase advance amount can be adjusted by changing the delay amount of the phase advance compensation observer.

  The present invention can be applied to a synchronous operation in a twin drive of a gantry type stage, a machine tool, a galvano scanner, and a double-arm robot (such as a fitting operation).

The block diagram of the synchronous control apparatus which shows the basic composition of this invention 1 is a block diagram of a synchronous control device showing a first embodiment of the present invention. The block diagram which shows the spindle motor model and delay model of 1st Example of this invention Block diagram of a conventional synchronous control device Block diagram of a conventional synchronous control device Block diagram of a conventional synchronous control device using phase advance filter processing Block diagram of a conventional synchronous control device using predictive control

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Master controller 2 Master control object 3 Slave controller 4 Slave controller 5 Slave state command calculator 6 Spindle motor 7 Slave motor 11 Phase lead compensation observer 12 Spindle motor model 13 Delay model 14 Observer gain 15 Command converter 16 Delay time adjuster 71 Main controller 72 Main shaft motor 73 Sub controller 74 Sub shaft motor 75 Predictor 76 Converter 77 Preview controller 78 Differentiator 79 Differentiator 80 Td multiplication 81 Td multiplication 82 J / Kt multiplication 83 Position controller 84 Speed controller

Claims (12)

A main controller that generates a main operation amount so that the main state amount of the main control object matches the main state amount command, and a subordinate state that generates a subordinate amount command so that the main state amount and the subordinate state amount are synchronized. In a synchronous control device comprising: a quantity command generator; and a slave controller that generates a slave operation amount so that the slave state quantity of the slave control object matches the slave state quantity command;
The slave state command generator generates the slave state amount command based on the main operation amount and the main state amount.   The sub-state quantity command generator includes a phase advance compensation computing unit that generates a phase advance main state quantity having a phase advanced from the main state quantity based on the main operation quantity and the main state quantity, and the phase advance main state The synchronous control device according to claim 1, further comprising: a command converter that converts a quantity into the slave state quantity command.   3. The synchronous control apparatus according to claim 2, wherein the phase advance compensation calculator is a phase advance compensation observer.   The phase advance compensation observer includes a control target model that generates the phase advance main state quantity from a main operation amount, a delay model that delays the phase advance main state quantity and generates a main state quantity estimated value, a main state quantity, An observer gain that generates a main operation amount correction value from a difference from the main state amount estimation value; and a subtractor that generates a new main operation amount by subtracting the main operation amount correction value from the main operation amount. The synchronous control device according to claim 3.   The synchronous control device according to claim 4, wherein the delay model includes dead time.   The synchronous control apparatus according to claim 4, wherein the delay model includes a low-pass filter.   6. The synchronous control device according to claim 5, wherein a dead time of the delay model is a parameter that can be changed by an operator, and the phase of the phase advance main state quantity is adjusted by changing the dead time parameter.   7. The cutoff frequency of the low-pass filter of the delay model is a parameter that can be changed by an operator, and the phase of the phase lead main state quantity is adjusted by changing the low-pass filter cutoff frequency parameter. The synchronous control device described.   6. The synchronization control device according to claim 5, further comprising a delay time adjuster that adjusts the dead time so that the sub state quantity falls within a predetermined synchronization range of the main state quantity.   7. The synchronization control apparatus according to claim 6, further comprising a delay time adjuster that adjusts a cutoff frequency of the low-pass filter so that the sub state quantity falls within a predetermined synchronization range of the main state quantity.   The main control target and the sub control target are motors, the main operation amount and the sub operation amount are commands proportional to acceleration, and the main state amount and the sub state amount are positions. The synchronous control device according to claim 1.   5. The synchronous control device according to claim 4, wherein the controlled object model is a motor model and outputs a value proportional to an input second-order integral.

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