TW202130111A - Motor control apparatus and motor control method - Google Patents

Abstract

A motor control apparatus that controls the torque of a motor while limiting speed on the basis of a torque command and a speed limit command, the motor control apparatus including: a speed detection unit configured to detect the speed of the motor; and a speed limiting unit configured to calculate a torque command-based speed command on the basis of the torque command and output a motor speed command obtained by adding a limit to the torque command-based speed command. The speed limiting unit includes: a speed command calculation unit configured to calculate the torque command-based speed command from the torque command; and a speed limiter configured to add a speed limit based on the speed limit command to the speed command and output the motor speed command, and the torque command-based speed command calculation unit includes: a speed error calculator configured to calculate a speed error on the basis of the torque command; and an adder configured to add the speed to the speed error and output the torque command-based speed command.

Description

Motor control device and motor control method

The present invention relates to a motor control device and a control method for limiting the speed of a motor and controlling the torque of the motor according to a torque command and a speed limit command.

In the production of paper, film, etc., in order to prevent wrinkles or slack and improve quality, a tension control device is used for the production. Under the control of the unwinding motor of such a tension control device, the unwinding motor is driven with a constant torque corresponding to the winding diameter to keep the tension constant.

Next, in order to suppress the increase in the speed of the unwinding motor when the workpiece is cut, a torque control with a speed limit function is implemented. Furthermore, in the case of a servo gun for spot welding, the welding wafer of the electrode part of the welding gun is used to enclose the workpiece, the torque of the motor is controlled and the pressure is applied, and electricity is applied between the electrode wafers to weld the workpiece.

Also in such a welding gun, the position control or speed control is used to move to the near side of the pressurized object. In order not to cause excessive speed when switching to torque control and collide with the pressurized object, a speed limit is implemented. Function torque control.

As an example of implementing torque control with such a speed limit function, there is Japanese Patent Laid-Open No. 2003-33068.

In Japanese Patent Application Laid-Open No. 2003-33068, a motor control device is described, which is a motor control device that controls a motor based on an input from the outside, and has: a motor that rotates in response to an applied voltage; The magnetic pole position sensor of the magnetic pole position; the speed calculation part that calculates the rotation speed of the motor according to the position signal output by the magnetic pole position sensor; the conversion part that converts the input from the outside into the torque current command; rotates according to the limit of the motor The speed and speed calculation unit calculates the motor rotation speed to correct the torque current command torque current correction part; uses the corrected torque current command to calculate the voltage command vector calculation part; and according to the voltage command to create The applied voltage creating part of the applied voltage of the motor.

However, in the method of correcting such a torque command with the output of the torque current correction unit, it is necessary to output the torque current correction to cancel the torque command when the speed is limited. When the torque command is large, there is a cancel signal. It also becomes larger, the response becomes slower, and the speed overshoot becomes large. Or, when the action is near the speed limit, the speed limit control will be intermittently performed, and there will be repeated large overshoots and the behavior becomes unstable. The problem is that only one speed limit command can be input, so the speed can only be limited in the direction of the torque command, or the speed cannot be limited because the direction cannot be determined when the torque command is 0.

As an example of solving the aforementioned problem that the speed can only be limited in the direction of the torque command, or the speed cannot be limited because the direction cannot be determined when the torque command is 0, there are international publications. Patent Bulletin No. 2011/145366.

In International Publication No. 2011/145366 Patent Publication, a motor control device is described, which is a motor control device that controls a motor that drives a driving object to apply a pressure corresponding to the target torque to the pressurized object. ,have: Calculate the speed controller used to compensate the torque command to the motor and the return torque of the torque command according to the speed detection value of the motor; and Calculate the return torque controller of the first speed command corresponding to the deviation of the target torque and the return torque calculated by the speed controller; The regressive torque controller limits the calculated first speed command to the desired speed limit value based on the contact speed of the driving object and the pressurized object and outputs it. The speed controller calculates the torque command to allow the speed detection value to follow. Return to the first speed command output by the torque controller.

In the method of International Publication No. 2011/145366 Patent Publication, the speed limit value can be set on both the forward rotation side and the reverse rotation side of the motor, and the speed can be limited regardless of the polarity of the torque command. The problem that the speed can be limited in the direction of the torque command, or the speed cannot be limited because the direction cannot be determined when the torque command is 0. However, the method of comparing such a torque command with the regressive torque and using the regressive torque controller to calculate the speed command to compensate for the torque command to the motor (motor torque command) does not increase the gain of the regressive torque controller to a considerable extent. , It will not generate a motor torque command like a torque command.

However, the regressive torque control loop is composed of two controllers consisting of a speed controller composed of a proportional integral controller and a regressive torque controller similarly composed of a proportional integral controller. The reason is that the integral element is doubled. Therefore, the control system tends to become unstable, and if the control gain is increased, the return torque will vibrate. If vibration occurs in the return torque, vibration will also occur in the motor torque command. For this reason, the gain cannot be increased for use, and there is a problem that the motor torque can only be output slightly smaller than the torque command.

In particular, if the proportional gain of the regressive torque controller is increased, it is easy to vibrate, and it cannot be used by increasing the proportional gain. Depending on the control parameters, there may be cases where the return from the speed limit state cannot operate properly, and it is difficult to adjust and stable operation parameters. The problem of narrow scope.

In addition, the integrator of the speed controller also operates as the integrator of the regressive torque controller. When the torque command changes suddenly, the integrator of the speed controller also operates. As a result, the speed overshoot becomes large. The problem is that when the operation is near the speed limit, the speed limit control will be intermittently performed, and the behavior will become unstable due to repeated large overshoots.

The motor control device according to the embodiment of the present disclosure limits the speed and controls the torque of the motor based on the torque command and the speed limit command; The aforementioned torque command calculates the speed command based on the torque command and outputs it to the speed limit part of the motor speed command limited to the speed command based on the aforementioned torque command; the aforementioned speed limit part is equipped with: calculates the speed based on the aforementioned torque command from the aforementioned torque command The commanded speed command calculation unit and the speed command based on the aforementioned torque command plus the speed limit based on the aforementioned speed limit command and output the aforementioned motor speed command; the speed command calculation unit based on the aforementioned torque command has: according to the aforementioned A speed deviation calculator that calculates the speed deviation by a torque command, and an adder that adds the aforementioned speed to the aforementioned speed deviation and outputs a speed command based on the aforementioned torque command. In the following detailed description, for explanatory purposes, many specific details are mentioned in order to provide an in-depth understanding of the disclosed implementation modes. However, it should be understood that one or more implementation aspects can be implemented without these specific details. In other different situations, well-known structures and devices are schematically shown to simplify the drawings.

The present invention was created to solve the aforementioned problems, and its purpose is to provide a motor control device and a motor control method, which are easy to adjust the control parameters, regardless of the polarity of the torque command or the rotation direction of the motor. The speed in the torque control can be limited, and the motor torque such as the torque command can be output when the overshoot at the speed limit is small and there is no speed limit.

The present invention is the following motor control device.

A motor control device that limits the speed and controls the torque of the motor based on a torque command and a speed limit command; the feature is that the motor control device has: a speed detection unit that detects the speed of the motor, and calculates the torque based on the torque command The commanded speed command is output to the speed limit part of the motor speed command based on the aforementioned torque command plus the limited motor speed command; the aforementioned speed limit part has: a speed command calculation part that calculates the speed command based on the aforementioned torque command from the aforementioned torque command , And a speed limiter that adds the speed limit based on the aforementioned speed limit command to the speed command based on the aforementioned torque command and outputs the aforementioned motor speed command; the speed command calculation unit based on the aforementioned torque command is equipped with: calculates the speed deviation based on the aforementioned torque command The speed deviation calculator, and the adder that adds the speed to the speed deviation and outputs the speed command based on the torque command.

Furthermore, the present invention is also the following motor control method.

A motor control method that limits the speed and controls the torque of the motor according to the torque command and the speed limit command; the characteristic is: calculate the speed deviation according to the aforementioned torque command; add the aforementioned speed of the aforementioned motor to the aforementioned speed deviation, thereby, Output the speed command based on the torque command; add the speed command based on the aforementioned torque command and the speed limit based on the aforementioned speed limit command to output the motor speed command.

The implementation of the motor control device and the motor control method of the present invention can be implemented in various ways as indicated in the appended items of the patent application. The details and advantages of these and other are used for implementation. The detailed description will be given in the item of the type of invention described later.

Through the foregoing structure, in the present invention, the inverse calculation method of calculating the motor torque command from the motor speed command under the speed control loop is performed, and the torque command is used to calculate the speed command based on the torque command, and the speed limit is performed to obtain It is a simple structure to output the motor speed command and control the speed of the motor according to the motor speed command, thereby realizing the speed limit in the torque control. For this reason, it is possible to realize a motor control device. The adjustment of special parameters is unnecessary. The speed can be limited regardless of the polarity of the torque command or the rotation direction of the motor. The overshoot at the speed limit is small and there is no speed. Under limited conditions, the motor torque can be output as a torque command.

Hereinafter, the implementation of the motor control device and method of the present invention will be described in detail based on the drawings. Moreover, no matter how the description of the implementation is not used to limit the scope of the present invention, as long as it belongs to the scope of the invention related to each claim in the scope of the patent application, any aspect is also covered by the present invention. The scope of the invention includes.

Figure 1 shows one of the states of the motor control device and method.

The motor control device A for controlling the motor torque T of the motor M of the present invention generally uses an encoder EN, a differentiator Dif, a speed deviation calculator 1, an adder 2, a subtractor for obtaining the motor speed S 3. Speed limiter 4, speed controller 5, motor torque controller 6 and so on.

Here, the encoder EN and the differentiator Dif used to obtain the motor speed S constitute a speed detection unit B that detects the motor speed S. In addition, the component system of the speed detection unit B is not only constituted by the encoder EN and the differentiator Dif, but can be constituted arbitrarily as long as the speed can be detected.

Furthermore, the speed deviation calculator 1 and the adder 2 constitute a speed command calculation unit C based on a torque command, and the speed command calculation unit C based on a torque command and the speed limiter 4 constitute a speed limit unit D.

In the motor control device A configured in this way, the torque command Tc for controlling the motor torque T of the motor M and the speed limit command Suc for limiting the motor speed S of the motor M are given from the outside. Under the constant speed limit, the motor M is operated.

The desired torque command Tc given from the outside is input to the speed deviation calculator 1, and the speed deviation Sd1 based on the torque command Tc is calculated and output.

In the speed deviation Sd1 based on the torque command Tc, the motor speed S output from the speed detection unit B is added in the adder 2, and the speed command Sc based on the torque command is output. The speed command Sc based on the torque command is input to the speed limiter 4, where the speed limit is performed based on the desired speed limit command Suc given from the outside, and the motor speed command Smc is calculated. According to the motor speed command Smc, the speed of the motor M is controlled.

Specifically, the position signal from the encoder EN attached to the motor M is differentiated by the differentiator Dif to obtain the motor speed S. The speed deviation Sd2 signal output by subtracting the motor speed command Smc and the motor speed S from the subtractor 3 is input to the speed controller 5, and the speed controller 5 calculates the motor torque command Tmc. According to the motor torque command Tmc, the motor torque T like the motor torque command Tmc is output from the motor M via the motor torque controller 6. The speed control loop is configured so that the position rotated by the motor torque T output from the motor M is detected by the encoder EN and coincides with the motor speed command Smc.

When the speed controller 5 is composed of a proportional controller and its gain is G, the calculation of the speed control loop is performed according to the following equations (1) and (2).

Motor speed command Smc-motor speed S=speed deviation Sd2···(1) Speed deviation Sd2×gain of proportional controller G=motor torque command Tmc···(2)

Using the two equations, the motor speed command Smc can be back-calculated from the motor torque command Tmc as follows.

Speed deviation Sd2=motor torque command Tmc/proportional controller gain G···(3) Motor speed command Smc=speed deviation Sd2+motor speed S···(4)

In the present invention, the following equations (5) and (6) are used for the torque command Tc given from the outside, and first, the speed command Sc based on the torque command is calculated.

Speed deviation based on torque command Sd1=torque command Tc/G···(5) Speed command based on torque command Sc = speed deviation based on torque command Sd1 + motor speed S···(6)

Next, for the speed command Sc based on the torque command that has been obtained, the speed limiter 4 performs speed limit based on the speed limit command Suc to obtain the motor speed command Smc.

If the motor speed control is performed according to the motor speed command Smc,

Motor torque command Tmc=speed deviation Sd2×G =(motor speed command Smc-motor speed S)×G

Here, without regard to the speed limit, that is, when the speed command Sc based on the torque command is smaller than the speed limit command Suc, the motor speed command Smc = the speed command Sc based on the torque command becomes:

Motor torque command Tmc=(speed command based on torque command Sc-motor speed S)×G ={(Speed deviation based on torque command Sd1+motor speed S)- Motor speed S}×G =(Speed deviation Sd1 based on torque command)×G = Torque command Tc/G×G = Torque command Tc

The motor torque command Tmc is consistent with the torque command Tc. The motor M is torque controlled according to the motor torque command Tmc, and the motor M is output from the motor M such as the motor torque command Tmc, that is, the motor torque T like the torque command Tc.

In the case of a speed limit, that is, when the speed command Sc based on the torque command is higher than the speed limit command Suc, the motor speed command Smc becomes the speed limit command Suc, and the speed of the motor M based on the speed limit command Suc is performed. control. The speed limit is only based on the speed deviation Sd1 of the torque command plus the motor speed S. There is no torque control loop used to realize the speed limit in the upper position of the speed control loop, and the special control parameter system that constitutes the control loop is unnecessary. .

Moreover, the speed limit command Suc can use one input to limit both the CW (clockwise rotation direction) side and the CCW (counterclockwise rotation direction) side, or two speed limit commands can be set to independently limit the CW side and the CCW side. .

Furthermore, the speed limit command Suc may also determine the upper limit of the motor speed S based on a predetermined threshold value, a predetermined table value, a predetermined function value, and the like. In this case, the "prescribed" naturally includes those that can be determined arbitrarily, and further, it also includes those that can be arbitrarily determined at any point in time such as the manufacture, testing, shipment, and use of the motor control device A, etc. Setter.

As described above, in the present invention, the motor torque command Tmc is calculated from the motor speed command Smc under the speed control system through the inverse calculation, and the torque command Tc is used to calculate the speed command Sc based on the torque command. Get the motor speed command Smc, and use the motor speed command Smc to calculate the motor torque command Tmc.

Moreover, even when the gain G of the speed controller 5 is low, the motor torque command Tmc is calculated as the torque command Tc when the speed limit is not yet set, and the gain G of the proportional controller of the speed controller 5 is not affected. Influence. The gain G of the speed controller 5 can be adjusted according to the usual practice in order to stabilize the speed loop when the speed control of the motor M is performed under normal operating conditions.

Fig. 2 shows another aspect of the motor control device and method.

In this situation, in the motor control device and method shown in FIG. 1, when the motor M, the shaft connected to it, or the mechanical system such as the winding device resonates, it is possible to set the notch filter A filter such as NF or low-pass filter LPF is provided on the output side of the speed controller 5. In this case, the response to the torque command Tc is reduced to the amount of a filter such as a low-pass filter LPF added. The rest of the composition is the same as the one described above.

In the case where the proportional controller constitutes the speed controller 5, there is no overshoot. In the case where the workpiece is cut during the tension control of the motor M, there is only the rotation friction of the unwinding part, the load torque is small, and the error caused by the motor speed limited by the proportional control is only a little point.

Two aspects are disclosed above. However, according to the application of the present invention, the load torque Tb with a load is large, and for the speed limit command Suc, there is a speed error of the load torque Tb divided by the gain G of the speed control. .

In this case, the speed controller 5 is constituted by a proportional integral controller, and operates as a proportional controller when there is no speed limit, and when there is a speed limit, the integral controller is made effective. In the case of a speed limit, the system uses an integral controller to suppress the influence of the load torque Tb. However, because the value output from the integral controller only outputs the value that compensates for the load torque Tb, the compensation amount of the integral controller is a little bit, and the overshoot of the motor speed is a little bit.

In addition, when the load torque Tb is large and the regeneration operation is performed, the integral controller of the proportional integral controller is turned off when there is a speed limit during regeneration. Although the speed error is generated, it has the effect of preventing the pulsation of the motor torque T generated by the integral controller repeatedly and intermittently during the regeneration.

Fig. 3 and Fig. 4 show the simulation results of the speed change in a plurality of modes of motor control and its method, and Fig. 5 shows the simulation result of the speed change of the operation example of the method of correcting the torque command. The vertical axis represents the magnitude of the speed, and the horizontal axis represents the passage of time. It is the chart under Suc which is all the same speed limit command.

In Fig. 3, in one of the states of the motor control and its method, the result of the case where there is no load torque when the time T is 0≦T≦0.25. In this time range, the speed limit appears as if the speed limit command Suc is set. In addition, in the range of 0.25≦T, it shows the result of the case where the load moment is present. In this time range, as described later, a speed error of the load torque Tb divided by the gain G of the speed control is generated for the speed limit command Suc. In this case, it is one of them after all, revealing an error ^{of 29.4 min -1.} In power, the limit is as low as only the stated error, and during regeneration, the limit is as high as only the stated error.

From one figure to FIG. 5, for the sake of comparison with the aforementioned motor control and method, an example of the operation of the method of correcting the torque command in Japanese Patent Laid-Open No. 2003-33068 is disclosed. Shows the result of the case where there is no load moment when the time T is 0≦T≦0.25. In addition, in the range of 0.25≦T, it shows the result of the case where the load moment is present. Also at any power, when the speed rises, ^{large overshoots such as 290 min -1} and 265 min ^{-1 are} generated, and if the torque command is 0 during regeneration, there is no speed limit. If the overshoot is large, it is because the output only cancels the torque command from the speed loop and the speed is limited. There is a time delay until a large cancel torque command is given.

Fig. 4 shows the simulation result of the speed change of another aspect of motor control and its method. This aspect indicates that the speed controller is configured to perform proportional integral control (PI control). It can be operated as a proportional control (P control) when the speed limit is not reached. When the speed limit is reached Next, let the integral controller be effective and perform the operation example of the speed proportional integral control (PI control). Shows the result of the case where there is no load moment when the time T is 0≦T≦0.25. In this time range, when there is no speed limit, the integral controller is activated and the torque is not eliminated, so it is limited to an overshoot of ^{30 min -1.} In addition, in the range of 0.25≦T, it shows the result of the case where the load moment is present. Also within this time range, when there is a speed limit, overshoot occurs due to the action of the integral controller. However, the amount of overshoot is relatively small compared to the example of the operation of the method of correcting the torque command shown in FIG. 5.

As mentioned above, in the aspect of the present invention, all can realize a motor control device, which is not necessary to adjust special parameters, and can limit the speed regardless of the polarity of the torque command or the rotation direction of the motor. When the overshoot at the speed limit is small and there is no speed limit, the motor torque can be output like a torque command.

The above-mentioned various aspects all represent one aspect of the present invention, and do not limit the specific configuration of the present invention itself based on these aspects. The scope of the present invention includes all the matters described according to the scope of the patent application, and all that can be assumed by those with ordinary knowledge in the technical field to which it belongs. For the purpose of illustration and description, the above detailed description has been presented. There are many modifications and variations based on the above teachings. It is not intended to exhaust the subject matter of the invention described herein or to limit the subject matter of the invention described herein to the specific precise form disclosed. Although the subject matter of the invention has been described in terms of specific structural features and/or methodological behaviors, it should be understood that the subject matter of the invention defined in the scope of the attached patent application is not necessarily limited to the specific features or behaviors mentioned above. On the contrary, the above-mentioned specific features and behaviors are disclosed as embodiments of the scope of the attached patent application.

1: Speed deviation calculator 2: adder 3: subtractor 4: Speed limiter 5: Speed controller 6: Motor torque controller A: Motor control device B: Speed detection department C: Speed command calculation unit D: Speed limit department M: Motor

[Fig. 1] Fig. 1 is a block diagram showing one aspect of the motor control device and method. [Fig. 2] Fig. 2 is a block diagram showing another aspect of the motor control device and method. [Fig. 3] Fig. 3 is a graph showing the speed variation simulation result of one state (speed proportional control) of the motor control device and method. [Fig. 4] Fig. 4 is a graph showing the simulation result of the speed change of another aspect of motor control and its method (speed proportional integral control). [Fig. 5] Fig. 5 is a graph showing a simulation result of a speed change in an operation example of a method of correcting a torque command.

1: Speed deviation calculator

2: adder

3: subtractor

4: Speed limiter

5: Speed controller

6: Motor torque controller

A: Motor control device

B: Speed detection department

C: Speed command calculation unit

D: Speed limit department

S: Motor speed

Sc: Speed command based on torque command

Sd1: Speed deviation based on torque command

Sd2: Speed deviation

Suc: Speed limit command

Smc: motor speed command

T: Motor torque

Tc: Torque command

Tmc: motor torque command

Claims (8)

A motor control device, which limits the speed and controls the torque of the motor according to the torque command and the speed limit command; its characteristics are: The motor control device has: a speed detection unit that detects the speed of the motor, and a speed limit unit that calculates a speed command based on a torque command based on the torque command and outputs the speed command based on the torque command plus a limited motor speed command ； The speed limit unit includes: a speed command calculation unit for calculating a speed command based on the torque command from the torque command, and a speed command based on the torque command plus a speed limit based on the speed limit command and outputting the motor speed command Speed limiter The speed command calculation unit based on the torque command includes a speed deviation calculator that calculates a speed deviation based on the torque command, and an adder that adds the speed to the speed deviation and outputs a speed command based on the torque command. Such as the motor control device of claim 1, wherein Also equipped with: a speed controller that calculates the motor torque command according to the aforementioned motor speed command; The aforementioned speed deviation calculator outputs the aforementioned speed deviation based on the aforementioned torque command through the following formula; The aforementioned speed deviation (Sd1) based on the aforementioned torque command = the aforementioned torque command (Tc)/the aforementioned speed controller gain (G). Such as the motor control device of claim 1 or 2, in which, The aforementioned speed limit command is that the upper limit of the aforementioned motor speed is determined based on a predetermined threshold, a predetermined table value, or a predetermined function value. Such as the motor control device of claim 2 or 3, in which, The aforementioned speed controller has at least one of a proportional controller or a proportional integral controller. A motor control method, which limits the speed and controls the torque of the motor according to the torque command and the speed limit command; its characteristics are: Calculate the speed deviation according to the aforementioned torque command; Add the aforementioned speed of the aforementioned motor to the aforementioned speed deviation, thereby outputting a speed command based on the torque command; The motor speed command is output by adding the speed command based on the aforementioned torque command to the speed limit based on the aforementioned speed limit command. Such as the motor control method of claim 5, wherein: Furthermore, through the speed controller, the motor torque command is calculated according to the aforementioned motor speed command; Calculate the aforementioned speed deviation based on the aforementioned torque command according to the following formula; The aforementioned speed deviation based on the aforementioned torque command (Sd1) = The aforementioned torque command (Tc)/the aforementioned speed controller gain (G). Such as the motor control method of claim 5 or 6, in which, The aforementioned speed limit command is that the upper limit of the aforementioned motor speed is determined based on a predetermined threshold, a predetermined table value, or a predetermined function value. Such as the motor control method of claim 6 or 7, in which, The aforementioned speed controller performs proportional control in torque control and proportional integral control in speed limit.

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