JP7737110B2 - Motor control device and motor control method - Google Patents

Description

The present invention relates to a motor control device and a motor control method.

A motor has a stator and a mover, and is configured to move the mover relative to the stator by generating a magnetic thrust between the two. A typical example of a motor is a linear motor, which has a mover with multiple permanent magnets arranged so that their magnetic properties alternate, and a stator with multiple magnetic pole teeth each wound with a coil, arranged a predetermined distance apart. When an alternating current is passed through the stator coil, thrust is generated by the attractive/repulsive force between the permanent magnets, causing the mover to move linearly relative to the stator.

For example, Patent Document 1 discloses that a PID servo algorithm unit performs feedback control of a linear motor using the velocity and position signal detected by a stage position detection device.

Japanese Patent Application Laid-Open No. 2000-167717

Many of the positioning stages used in semiconductor transport equipment use linear motors. These stages can be broadly divided into stepper types, in which exposure and other processes are performed while the stage is stationary, and scanner types, in which processing is performed while the stage moves at a constant speed. To improve processing precision, stepper types require the ability to stop quickly on command, i.e., high responsiveness, while scanner types require reduced speed fluctuations when moving at a constant speed.

To satisfy these requirements, a stage that uses feedback control, such as that described in Patent Document 1, requires either increasing the rigidity of the stage or adding additional equipment for early stopping of the stage. However, in either case, expensive components are used, which increases the manufacturing costs of the stage.

The present invention was made in consideration of these circumstances, and aims to provide a motor control device and motor control method that can reduce speed fluctuation rate during constant speed operation and achieve early stopping at low cost.

The motor control device of the present invention is a motor control device that performs disturbance compensation and includes a first control system for reducing the speed fluctuation rate when the motor is moving at a constant speed, and a second control system for shortening the settling time when the motor stops.

In this invention, the first control system reduces the speed fluctuation rate when the motor is moving at a constant speed, and the second control system shortens the settling time when the motor is stopped, thereby achieving both a reduction in speed fluctuation rate when the motor is moving at a constant speed and early stopping.

In the motor control device of the present invention, the second control system performs feedforward control of the motor using the disturbance-corrected input value input to the motor.

In the present invention, the second control system performs the feedforward control using the disturbance-corrected input value input to the motor. Since the input value that has already undergone disturbance correction is used for feedforward control, the motor disturbance suppression effect can be improved.

The motor control device according to the present invention includes a storage unit that stores the actual measured values of the input values in advance, and the second control system performs the feedforward control using the actual measured values of the input values.

In this invention, the second control system performs the feedforward control using the actual measured value of the disturbance-corrected input value input to the motor. Therefore, since the input value that has already been disturbance-corrected is used for feedforward control, the motor disturbance suppression effect can be improved.

In the motor control device according to the present invention, the first control system includes a nonlinear compensator that determines a first disturbance estimate used to suppress periodic disturbances, and a disturbance observer that determines a second disturbance estimate used to suppress non-periodic disturbances.

In this invention, the first control system performs disturbance control by suppressing periodic disturbances using a first disturbance estimate determined by the nonlinear compensator, and suppressing non-periodic disturbances using a second disturbance estimate determined by the disturbance observer. Therefore, disturbances that occur when the motor is at a constant speed are significantly suppressed, and the speed fluctuation rate is reduced.

The motor control device of the present invention includes a controller that performs feedback control of the motor based on the difference between the position of an object driven by the motor and a position command value for the motor; a first subtractor that calculates the difference between the output value of the controller and the second disturbance estimated value; and a second subtractor that calculates the difference between the first disturbance estimated value and the sum of the output value of the first subtractor and the output value of the second control system, and outputs the difference to the motor.

In this invention, the feedforward control by the second control system is added to the results of the feedback control by the controller, and then disturbance control is performed by the first control system. This reduces the speed fluctuation rate when the motor is running at a constant speed, and enables the motor to be stopped quickly.

The motor control method of the present invention controls a motor by performing disturbance correction, and performs a first control to reduce the speed fluctuation rate when the motor is moving at a constant speed, and a second control to shorten the settling time when the motor stops.

In this invention, the first control reduces the speed fluctuation rate when the motor is moving at a constant speed, and the second control shortens the settling time when the motor is stopped, thereby achieving both a reduction in the speed fluctuation rate when the motor is moving at a constant speed and early stopping.

In the motor control method according to the present invention, the second control involves performing feedforward control of the motor using the disturbance-corrected input value input to the motor.

In the present invention, the feedforward control is performed using the disturbance-corrected input value input to the motor in the second control. Therefore, since the input value that has already been subjected to disturbance correction is used for the feedforward control, the motor disturbance suppression effect can be enhanced.

The motor control method of the present invention stores the actual measured value of the input value in advance, and the second control performs the feedforward control using the actual measured value of the input value.

In the present invention, the feedforward control is performed using the actual measured value of the disturbance-corrected input value input to the motor in the second control. Therefore, since the input value that has already been subjected to disturbance correction is used in the feedforward control, the motor disturbance suppression effect can be improved.

In the motor control method according to the present invention, the first control determines a first disturbance estimate used to suppress periodic disturbances and a second disturbance estimate used to suppress non-periodic disturbances.

In the present invention, the first control system performs disturbance control by determining the first disturbance estimated value to suppress periodic disturbances and by determining the second disturbance estimated value to suppress non-periodic disturbances. Therefore, disturbances that occur when the motor is at a constant speed are significantly suppressed, and the speed fluctuation rate is reduced.

A motor control method according to the present invention performs feedback control of the motor based on the difference between the position of an object driven by the motor and a position command value for the motor, calculates the difference between the value obtained by the feedback control and the second disturbance estimated value, calculates the difference between the sum of the calculated difference and the value obtained by the feedforward control and the first disturbance estimated value, and outputs the difference to the motor.

In this invention, the feedforward control is added to the results of the feedback control, and then the disturbance control is performed. This reduces the speed fluctuation rate when the motor is moving at a constant speed, and enables the motor to be stopped quickly.

This invention makes it possible to reduce speed fluctuations during constant speed operation and achieve early stopping at low cost.

FIG. 2 is a perspective view showing the configuration of a linear motor. FIG. 2 is a side view showing the configuration of a linear motor. FIG. 2 is a block diagram showing the configuration of an embodiment of a control device according to the present embodiment. FIG. 4 is an illustrative diagram showing an example of a current command input to a linear motor. FIG. 4 is an illustrative diagram showing an example of a feedforward value used in feedforward control. FIG. 2 is a block diagram showing the internal configuration of a disturbance control system of the control device. 4 shows operational waveforms when disturbance observer control is performed by the control device according to the present invention. 6 shows operational waveforms when feedforward control is performed using the feedforward values shown in FIG. 5.

The present invention will be described in detail with reference to drawings showing embodiments thereof. The following describes the application of the present invention to a positioning stage that uses a linear motor as an example of a motor.

Figures 1 and 2 are a perspective view and a side view showing the configuration of a linear motor 1. The linear motor 1 has a mover 2 and a stator 3 that face each other and are spaced a predetermined distance apart.

The mover 2 is composed of, for example, 14 rectangular permanent magnets 21, supported and fixed at equal intervals on a thin plate-shaped back yoke 22, and arranged side by side in the direction of movement (left and right in Figure 2). Each permanent magnet 21 is magnetized in the thickness direction (up and down in Figure 2), with adjacent permanent magnets 21, 21 having opposite magnetization directions. In other words, permanent magnets 21 magnetized in the direction from the mover 2 side toward the stator 3 side (top to bottom in Figure 2) and permanent magnets 21 magnetized in the direction from the stator 3 side toward the mover 2 side (bottom to top in Figure 2) are arranged alternately.

Meanwhile, the stator 3 is constructed by integrally forming, for example, 30 rectangular magnetic pole teeth 32 at equal intervals in the direction of movement on a thin plate-shaped core 31, with coils 33 wound around each magnetic pole tooth 32. U, V, and W in Figure 2 respectively represent the U, V, and W phases of a three-phase AC power supply, and three pairs of forward and reverse slots form one set to allow for three-phase parallel current flow. The linear motor 1 has a basic unit with a seven-pole, six-slot configuration, including seven permanent magnets 21, six magnetic pole teeth 32, and coils 33.

When a three-phase alternating current is applied to the coils 33 of the stator 3 to generate a magnetic field in the magnetic pole teeth 32, the permanent magnets 21 of the mover 2 are sequentially magnetically attracted and repelled by this magnetic field, generating a thrust in the mover 2, causing the mover 2 to move linearly relative to the stator 3.

The following describes in detail a method and device for reducing the effects of disturbances that inevitably occur in a linear motor 1 configured as described above.

In this invention, control is performed by adding nonlinear compensation control to basic control (feedback control) to suppress periodic disturbances, disturbance observer control to suppress other non-periodic disturbances, and feedforward control to shorten settling time. Nonlinear compensation control suppresses periodic disturbances, mainly cogging, in the constant velocity range. Disturbance observer control uses a steady-state Kalman filter to suppress disturbances that cannot be fully suppressed by nonlinear compensation control in the constant velocity range. Hereinafter, nonlinear compensation control and disturbance observer control will be collectively referred to as disturbance control.

Taking the linear motor 1 as an example, disturbances include the effect of tension in the current-carrying cable (a phenomenon in which tension causes a difference in thrust between the forward and backward directions of the linear motor 1), friction, and vibration of the base on which the linear motor 1 is held. In the present invention, the effect of such disturbances on the linear motor 1 is suppressed by feedforward control and disturbance control.

Figure 3 is a block diagram showing the configuration of one embodiment of the control device 10 according to this embodiment. The control device 10 is attached to the stage 11 (object) and appropriately controls the linear motor 1 that drives the stage 11.

The control device 10 includes a position command unit 80, a control controller 50 (controller), an FF corrector (feedforward corrector) 40 (second control system), a memory unit 41, a nonlinear compensator 51, a disturbance observer 61, a differentiator 62, a third subtractor 81, a first subtractor 71, and a second subtractor 72. The nonlinear compensator 51, the disturbance observer 61, and the differentiator 62 form a disturbance control system 60.

The input terminal of the linear motor 1 to be controlled is connected to the output terminal of the second subtractor 72. The output terminal of the linear motor 1 is connected to the input terminal of the nonlinear compensator 51, the input terminal of the differentiator 62, and the subtraction input terminal of the third subtractor 81. The output terminal of the nonlinear compensator 51 is connected to the subtraction input terminal of the second subtractor 72, one of the addition input terminals of the second subtractor 72 is connected to the output terminal of the FF corrector 40, and the other addition input terminal of the second subtractor 72 is connected to the output terminal of the first subtractor 71. The output terminal of the differentiator 62 is connected to the input terminal of the disturbance observer 61, and the output terminal of the disturbance observer 61 is connected to the subtraction input terminal of the first subtractor 71. The addition input terminal of the first subtractor 71 is connected to the output terminal of the control controller 50. The input terminal of the control controller 50 is connected to the output terminal of the third subtractor 81. The addition input terminal of the third subtractor 81 and the input terminal of the FF corrector 40 are connected to the output terminal of the position command unit 80. The FF corrector 40 is also connected to a memory unit 41.

The input command u1 (position command value) is input to the addition input terminal of the third subtractor 81 from the position command unit 80, the current command u3 is input to the addition input terminal of the first subtractor 71 from the control controller 50, and the second disturbance estimate value ^d (estimated value of a non-periodic disturbance) is input to the subtraction input terminal of the first subtractor 71 from the disturbance observer 61. The current command u2 is input to one addition input terminal of the second subtractor 72 from the FF corrector 40, the current command u4 is input to the other addition input terminal of the second subtractor 72 from the first subtractor 71, and the first disturbance estimate value ^i (estimated value of a periodic disturbance) is input to the subtraction input terminal of the second subtractor 72 from the nonlinear compensator 51. The symbol "^" represents an estimate.

A current command u (input value) is input to the linear motor 1. The current command u is a current command output from the second subtractor 72 to the linear motor 1 side, and is a current value input to, for example, a driver or servo amplifier (not shown), and output from the driver or servo amplifier to the linear motor 1.

Figure 4 is an illustrative diagram showing an example of a current command u input to the linear motor 1. In Figure 4, the command speed is the speed corresponding to the input command u1. As can be seen from Figure 4, the current command u changes over time and in accordance with the speed.

In addition, the position of the stage 11 is detected by a position detection unit (not shown) provided on the stage 11, and position information x representing the position of the stage 11 is output to the subtraction input terminal of the third subtractor 81, the differentiator 62, the nonlinear compensator 51, and to the outside.

The position command unit 80 outputs an input command u1 to the linear motor 1 in order to control the position of the stage 11 according to a predetermined program. The input command u1 is input to the FF corrector 40 and also input to the controller 50 via the third subtractor 81.

The controller 50 performs feedback control on the input command u1.
That is, the third subtractor 81 calculates the difference between the input command u1 input to the addition input terminal and the position information x input to the subtraction input terminal, and a difference signal representing this difference is input to the control controller 50. The control controller 50 applies proportional (P), integral (I), and differential (D) processing to this difference so as to match the input command u1 with the position information x, calculates a current command u3, and outputs it to the first subtractor 71.

Furthermore, the FF corrector 40 performs feedforward control on the input command u1 when the linear motor 1 stops, as will be explained in detail below.
The FF corrector 40 is connected to a storage unit 41. A plurality of patterns of feedforward values are stored in the storage unit 41. That is, the storage unit 41 stores a lookup table in which a feedforward value is associated with each input command u1.
The feedforward value stored in the memory unit 41 is the actually measured current command u, which is the current command u for the time range (hereinafter referred to as the settling interval) related to the settling time when the linear motor 1 stops (see the dashed ellipse in Figure 4).

Here, the settling time is the time it takes for the response to settle within a specified range of the target value after the commanded speed becomes 0 when the response is oscillatory. In this embodiment, for example, in the case of linear motor 1 (stage 11), it is the time it takes for the vibration to settle within ±150 nm after the commanded speed becomes 0. Furthermore, the settling interval is a time range in a time series that includes the settling time and also includes a specified time immediately before and after the settling time.

In the present invention, the stage 11 is operated in advance, and the current command u input to the linear motor 1 at this time, with disturbances suppressed, is measured. Of the measured current commands u, the current command u corresponding to the settling interval is stored in the memory unit 41 as a feedforward value.

In other words, this feedforward value is a current command that has undergone feedback control by the controller 50 and disturbance control by the disturbance control system 60, and is a corrected current command that has already undergone correction for the disturbance and is in a state where the disturbance has been suppressed.

Figure 5 is an illustrative diagram showing an example of a feedforward value used in feedforward control. In Figure 5, the command speed is the speed corresponding to the input command u1. The feedforward value is zero before the command speed becomes zero, but indicates a predetermined value after the command speed becomes zero. As can be seen from Figures 4 and 5, the feedforward value is approximately the same as the current command u corresponding to the settling interval.

The FF corrector 40 performs feedforward control when the linear motor 1 stops, using the feedforward value stored in the storage unit 41. That is, when an input command u1 corresponding to stopping the linear motor 1 is input, the FF corrector 40 obtains the feedforward value from the storage unit 41 and performs feedforward control.
For example, the FF corrector 40 does not perform feedforward control before the command speed becomes zero, or performs feedforward control using zero as the feedforward value, and when the command speed becomes zero, that is, just before the linear motor 1 stops, performs feedforward control using the feedforward value shown in Figure 5.
In detail, the FF corrector 40 performs a predetermined processing on the input command u1 from the position command unit 80, appropriately selects one of the feedforward values stored in the memory unit 41 in accordance with the input command u1, multiplies it by the input command u1, and outputs the current command u2 to the second subtractor 72.

In this way, the FF corrector 40 uses the corrected current command u, which has already undergone disturbance correction, as the feedforward value for feedforward control, thereby effectively suppressing disturbances. This removes disturbances related to stopping the linear motor 1 and shortens the settling time of the linear motor 1, meaning that the linear motor 1 can be stopped more quickly.

The disturbance control system 60 performs disturbance control to reduce the speed fluctuation rate when the linear motor 1 is moving at a constant speed. The disturbance control system 60 includes a nonlinear compensator 51 that determines a first disturbance estimate ^i used to suppress periodic disturbances that occur when the linear motor 1 is moving at a constant speed, and a disturbance observer 61 that determines a second disturbance estimate ^d used to suppress non-periodic disturbances other than periodic disturbances. In other words, the disturbance control includes nonlinear compensation control that suppresses periodic disturbances, using the first disturbance estimate ^i determined by the nonlinear compensator 51, and disturbance observer control that suppresses non-periodic disturbances, using the second disturbance estimate ^d determined by the disturbance observer 61.

Figure 6 is a block diagram showing the internal configuration of the disturbance control system 60 of the control device 10. Note that in Figure 6, the same parts as in Figure 3 are assigned the same numbers and symbols. As described above, the nonlinear compensator 51 determines and outputs the first disturbance estimate value ^i based on the position information x from the stage 11, and the disturbance observer 61 determines and outputs the second disturbance estimate value ^d based on the position information x from the stage 11.

The disturbance observer 61 has a steady-state Kalman filter 100. The steady-state Kalman filter 100 is a type of infinite impulse response filter used to estimate or control the state of a dynamic system using actual measurements that contain errors. The steady-state Kalman filter 100 is widely used to estimate quantities that change over time (for example, the position and velocity of an object) from actual measurements that contain discrete errors.

The disturbance observer 61 has a first parameter section 86, a second parameter section 87, a third parameter section 88, a fourth parameter section 89, a fifth parameter section 90, a first adder 91, a second adder 92, a subtractor 93, a first integrator 94, and a second integrator 95. Of these components, the first parameter section 86, the second parameter section 87, the third parameter section 88, the fourth parameter section 89, the first adder 91, the second adder 92, the subtractor 93, and the first integrator 94 constitute a steady-state Kalman filter 100.

The input terminal of the second parameter unit 87 is connected to the output terminal of the control controller 50, and the output terminal of the second parameter unit 87 is connected to one of the addition input terminals of the first adder 91. The input terminal of the first integrator 94 is connected to the output terminal of the first adder 91, and the output terminal of the first integrator 94 is connected to the input terminal of the first parameter unit 86 and the input terminal of the third parameter unit 88. The output terminal of the third parameter unit 88 is connected to the subtraction input terminal of the subtractor 93. The addition input terminal of the subtractor 93 is connected to the output terminal of the differentiator 62. The output terminal of the subtractor 93 is connected to the input terminal of the fourth parameter unit 89 and the input terminal of the fifth parameter unit 90. The output terminal of the first parameter unit 86 is connected to one of the addition input terminals of the second adder 92, and the output terminal of the fourth parameter unit 89 is connected to the other addition input terminal of the second adder 92. The output terminal of the second adder 92 is connected to the other addition input terminal of the first adder 91. The output terminal of the fifth parameter unit 90 is connected to the input terminal of the second integrator 95, and the output terminal of the second integrator 95 is connected to the subtraction input terminal of the first subtractor 71.

The first parameter section 86, second parameter section 87, and third parameter section 88 store the state variable parameters A, B, and C of the model (input: current, output: speed), respectively. These parameters A, B, and C are derived according to a MATLAB (registered trademark) program.

Furthermore, the fourth parameter section 89 stores a model state estimation parameter _Lx , and the fifth parameter section 90 stores a disturbance estimation parameter _Ld of the linear motor 1. The parameter _Lx is a model gain that defines the sensitivity to an error that occurs between the waveform of the compared model and the waveform of the actual machine, and if correction is desired even for a small error, this parameter _Lx is set to a large value. Similarly to the parameter _Lx , the parameter _Ld is also a model gain that defines the sensitivity in correction.

In actual implementation, it is preferable to use discretized values for each of these parameters.

An estimated value of the velocity waveform when a current command u3 is input from the controller 50 to the model (a velocity waveform when there is no influence of disturbance) is calculated. This calculated velocity waveform of the model is compared with the actual velocity waveform of the linear motor 1 obtained by differentiating the position information x by a differentiator 62, and the difference is calculated by a subtractor 93. In this way, the estimated value from the model is used to estimate the movement of the dynamic system (controlled object), and a fixed value is used for the parameter _Lx as a model gain, so the system takes the form of a steady-state Kalman filter.

The difference (error) obtained by the subtractor 93 is used to determine a second disturbance estimate ^d, which is an estimate of the non-periodic disturbance, and the determined second disturbance estimate ^d is subtracted from the current command u3 by the first subtractor 71 to reduce the non-periodic disturbance. In this way, of the disturbances that occur when the linear motor 1 is moving at a constant speed, non-periodic disturbances are suppressed (disturbance observer control).

The first subtractor 71 calculates the difference between the current command u3 input to the addition input terminal and the second disturbance estimate value ^d input to the subtraction input terminal, and outputs the current command u4 to the second subtractor 72.

The nonlinear compensator 51 compensates for periodic disturbances, such as cogging, that occur when the linear motor 1 is moving at a constant speed. The nonlinear compensator 51 applies inverse correction to the state of the periodic disturbance based on the position information x, and outputs a first disturbance estimate ^i, which is an estimate of the disturbance correction, to the second subtractor 72. This first disturbance estimate ^i is derived from a model of the disturbance element. The second subtractor 72 subtracts the first disturbance estimate ^i input to its subtraction input terminal from the sum of the current command u2 input to one addition input terminal and the current command u4 input to the other addition input terminal, thereby reducing the periodic disturbance. In this way, the periodic disturbance that occurs when the linear motor 1 is moving at a constant speed is suppressed (nonlinear compensation control).

In this way, in the present invention, when the linear motor 1 is moving at a constant speed, inverse compensation control of periodic disturbances is performed using the first disturbance estimate value ^i determined by the nonlinear compensator 51, and non-periodic disturbances are suppressed using the second disturbance estimate value ^d determined by the disturbance observer 61. In other words, the effects of periodic disturbances are roughly removed using the nonlinear compensator 51, and the effects caused by non-periodic disturbances are reduced using the disturbance observer 61.

The second subtractor 72 receives the feedforward controlled current command u2 at one addition input terminal, receives the current command u4 obtained by subtracting the second disturbance estimate value ^d from the feedback controlled current command u3 at the other addition input terminal, and receives the first disturbance estimate value ^i from the nonlinear compensator 51 at its subtraction input terminal. The second subtractor 72 calculates the difference between the sum of the current command u2 and the current command u4 and the first disturbance estimate value ^i, and outputs the current command u to the linear motor 1.

As described above, the control device 10 according to the present invention combines feedback control by the control controller 50, feedforward control by the FF corrector 40, and disturbance control (nonlinear compensation control and disturbance observer control) by the disturbance control system 60.

That is, when the linear motor 1 is moving at a constant speed, disturbance control is performed to suppress periodic disturbances and non-periodic disturbances, and when the linear motor 1 stops, feedforward control is performed in addition to the disturbance control.
By using a combination of controls in this way, the control device 10 according to the present invention can reduce the speed fluctuation rate when the linear motor 1 is moving at a constant speed and stop the linear motor 1 early at low cost.

Next, the results when the control according to the present invention is carried out will be described.
Fig. 7 shows operational waveforms when disturbance observer control is performed by the control device 10 according to the present invention. In Fig. 7, "A-1", "A-2", and "A-3" indicate a case where only feedback control by the control controller 50 is performed (Comparative Example 1), and "B-1", "B-2", and "B-3" indicate a case where feedback control by the control controller 50 and disturbance control by the disturbance control system 60 are performed (Example of the present invention).

Also, "A-1" and "B-1" show the overall operating waveform of the speed from the start of operation to the stop of the linear motor 1 (stage 11), with the horizontal axis representing time [sec] and the vertical axis representing speed [mm/s]. Also, the dashed line represents the command speed, and the solid line represents the actual speed.
Furthermore, "A-2" and "B-2" indicate the speed fluctuation rate (%) in the section of the overall operating waveform where the linear motor 1 moves at a constant speed and is a "+" value, and "A-3" and "B-3" indicate the speed fluctuation rate (%) in the section where the linear motor 1 moves at a constant speed and is a "-" value. In "A-2", "A-3", "B-2", and "B-3", the horizontal axis represents time [sec], the left vertical axis represents speed [mm/s], and the right vertical axis represents speed fluctuation rate (%). Also, the dashed line indicates the command speed, and the solid line represents the speed fluctuation rate (%).

When comparing the present invention example with comparative example 1, the effects of periodic and non-periodic disturbances are reduced in the present invention example, and the speed fluctuation rate (%) when the linear motor 1 is moving at a constant speed is significantly reduced from 1.0% in comparative example 1 to 0.1%.

Figure 8 shows the operating waveforms when feedforward control is performed using the feedforward values shown in Figure 5. In Figure 8, "A-1" and "A-2" indicate the case where only disturbance control by the disturbance control system 60 is performed (Comparative Example 2), while "B-1" and "B-2" indicate the case where both disturbance control by the disturbance control system 60 and feedforward control by the FF corrector 40 are performed (Example of the present invention).

Furthermore, "A-1" and "B-1" show the overall operating waveform of the speed from the start of operation to the stop of the linear motor 1 (stage 11), with the horizontal axis representing time [sec], the left vertical axis representing speed [mm/s], and the right vertical axis representing position deviation [μm].
Furthermore, "A-2" and "B-2" show enlarged views of the settling section of the overall operating waveform, with the horizontal axis representing time [sec], the left vertical axis representing speed [mm/s], and the right vertical axis representing position deviation [μm].
Here, the position deviation indicates the deviation from the target stop position.

Comparing the present invention example with comparative example 2, as shown in Figure 8, the settling time in the present invention example is significantly reduced from 230 msec in comparative example 2 to 140 msec through feedforward control.

The disclosed embodiments should be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the claims, not by the above description, and all modifications within the meaning and scope of the claims are intended to be embraced.

1 Linear motor 10 Control device 11 Stage (object)
40 FF corrector (second control system)
41 Memory unit 50 Controller (controller)
51 Nonlinear compensator 60 Disturbance control system (first control system)
61 Disturbance observer 71 First subtractor 72 Second subtractor 100 Steady-state Kalman filter u Current command (input value)

Claims (8)

In a motor control device that performs disturbance correction,
a first control system for reducing a speed fluctuation rate when the motor is moving at a constant speed;
a second control system for shortening a settling time when the motor is stopped ;
The second control system is a motor control device that performs feedforward control of the motor using the disturbance-corrected input value input to the motor . a storage unit that stores in advance the actual measured values of the input values,
The motor control device according to claim 1 , wherein the second control system performs the feedforward control using an actual measurement value of the input value. The first control system
a nonlinear compensator that determines a first disturbance estimate used to suppress the periodic disturbance;
3. The motor control device according to claim 1 , further comprising a disturbance observer that determines a second disturbance estimate used to suppress a non-periodic disturbance. a controller that performs feedback control of the motor based on a difference between a position of an object driven by the motor and a position command value for the motor;
a first subtractor that calculates a difference between the output value of the controller and the second disturbance estimate value;
a second subtractor that calculates a difference between an added value of an output value of the first subtractor and an output value of the second control system and the first disturbance estimated value,
4. The motor control device according to claim 3 , wherein the second subtractor outputs the difference to the motor. A motor control method for controlling a motor by performing disturbance correction, comprising:
performing a first control for reducing a speed fluctuation rate when the motor is rotating at a constant speed;
performing a second control for shortening a settling time when the motor is stopped;
In the second control, the disturbance-corrected input value input to the motor is used to perform feedforward control of the motor. The actual measured values of the input values are stored in advance;
The motor control method according to claim 5 , wherein the second control performs the feedforward control using an actual measurement value of the input value. The first control is
determining a first disturbance estimate used for suppressing the periodic disturbance;
7. The motor control method according to claim 5 , further comprising determining a second disturbance estimate value used for suppressing non-periodic disturbances. feedback control of the motor based on a difference between a position of an object driven by the motor and a position command value for the motor;
determining a difference between the value obtained by the feedback control and the second disturbance estimated value;
calculating a difference between the sum of the calculated difference and the value obtained by the feedforward control and the first disturbance estimated value;
The motor control method according to claim 7 , wherein the difference is output to the motor.