JP7219115B2 - Disturbance suppression control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disturbance suppression control device capable of suppressing a disturbance force applied to a controlled object.

A disturbance observer is known as a method of suppressing a disturbance force acting on a controlled object (see, for example, Patent Document 1). FIG. 13 is a block diagram of a control device 61 with a conventional disturbance observer. 62 is a control unit that outputs a force command (thrust command or torque command), _fd is a disturbance force, 63 is a controlled object (motor and driving machine), 64 is a disturbance observer, and 65 is a nominal model of the controlled object. , 66 is a low-pass filter.

The control unit 62 outputs the force command f _ref based on the position command X _ref and the position feedback information X of the controlled object 63, for example. A disturbance force f _d is added to the force command f _ref . Even if the control unit 62 outputs the force command f _ref for optimally operating the motor, the force command f _ref is not applied to the controlled object 63 as designed, and f _ref +f _d is applied. The disturbance observer 64 has a role of removing this disturbance force _fd .

The disturbance observer 64 comprises a nominal model inverse system 65 . The nominal model is an idealized model P̂(s) of the controlled object 63, and is defined by a formula such as a transfer function. For the nominal model P̂(s), P̂- ¹ (s) satisfying P̂(s)·P̂- ¹ (s)=1 is the inverse system.

The disturbance observer 64 inputs the position feedback information X of the controlled object 63 to the inverse system P̂ ⁻¹ (s) and calculates the force f̂(f̂=f _ref ). Next, the disturbance observer 64 extracts the corrected force command f _ref −f _d ̂ from the extraction point 67, and subtracts f _ref −f _d ̂ from the force f ̂ to obtain the estimated disturbance force f _d ̂. calculate. Then, the estimated disturbance force f _d ^ is input to the low-pass filter 66 to remove noise, and then the subtractor 68 subtracts the estimated disturbance force f _d ^ from the force command f _ref . The disturbance force f _d is canceled by the estimated disturbance force f _d ^. Therefore, the force command f _ref can be applied to the controlled object 63 as designed. Note that there is a subtraction point (subtractor 68) at which the disturbance observer 64 subtracts the estimated disturbance force f _d ^ from the force command f _ref before the extraction point 67 . This is because the disturbance force f _d is offset by the estimated disturbance force f _d ^.

JP 2016-140967 A

However, in the conventional disturbance observer, since the only adjustable parameter is the time constant τ of the low-pass filter, there is a problem that there is a limit to the disturbance suppression capability.

In addition, since the conventional disturbance observer has frequency characteristics of differential characteristics, there is a problem that the differential characteristics also appear in the positional deviation after disturbance suppression. For this reason, a reverse response may occur in the positional deviation after the suppression of the disturbance, and for example, excessive cutting may occur in cutting or the like.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a disturbance suppression control device having a high disturbance suppression capability.

In order to solve the above-described problems, one aspect of the present invention provides a control unit that outputs a force command, and inputs feedback information of a controlled object to an inverse system of a nominal model of the controlled object to calculate a force. a disturbance force suppression unit that calculates a force deviation based on the command and the force, calculates a correction amount based on the force deviation and the proportional gain, and adds or subtracts the correction amount to or from the force command; In the disturbance suppression control device, there is an addition point or a subtraction point at which the disturbance force suppression section adds or subtracts the correction amount to or from the force command after a draw point from which the disturbance force suppression section derives the force command.

According to the present invention, a force control feedback loop can be formed so as to suppress the disturbance force. By adjusting the correction amount with the proportional gain of this feedback loop, the disturbance suppression capability can be enhanced. In addition, it is possible to make it difficult for a reverse response to occur in the positional deviation after disturbance suppression.

1 is a block diagram of a disturbance suppression control device according to a first embodiment of the present invention; FIG. FIG. 5 is a block diagram of a disturbance suppression control device according to a second embodiment of the present invention; FIG. 11 is a block diagram of a disturbance suppression control device according to a third embodiment of the present invention; It is a figure which shows the structure of the drive system of the control system to which the disturbance suppression control apparatus of this embodiment is applied. FIG. 5(a) is a block diagram of the control system before equivalent conversion, and FIG. 5(b) is a block diagram of the control system after equivalent conversion. FIG. 6(a) is a block diagram before equivalent conversion of the control system incorporating the disturbance suppression control device of the first embodiment of the present invention, and FIG. 6(b) is a block diagram after equivalent conversion. . FIG. 7(a) is a block diagram of a control system incorporating a disturbance suppression control device according to a second embodiment of the present invention before equivalent conversion, and FIG. 7(b) is a block diagram after equivalent conversion. . FIG. 8(a) is a graph (simulation) of the frictional force, FIG. 8(b) is a graph (simulation) of the positional deviation generated without correction of the disturbance force, and FIG. It is a graph (simulation) of the position deviation which occurs after correction|amendment by a disturbance suppression control apparatus. It is a graph (experimental) of the positional deviation that occurs without disturbance force correction. 5 is a graph (experimental) of positional deviation generated after correction by the disturbance suppression control device of the present embodiment. 4 is a graph showing changes in positional deviation when τ is changed. Fig. 12(a) is a graph showing changes in positional deviation when β and K are changed (Fig. 12(a) is for β = 1 and K = 1; Fig. 12(b) is for β = 1 and K = 60); , FIG. 12(c) for β=0.4 and K=150). 1 is a block diagram of a conventional disturbance observer; FIG.

A disturbance suppression control device according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings. However, the disturbance suppression control apparatus of the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein. The present embodiments are provided with the intention of allowing those skilled in the art to fully understand the scope of the invention through a thorough disclosure of the specification.
(First embodiment)

FIG. 1 is a block diagram of a disturbance suppression control device according to a first embodiment of the present invention. In FIG. 1, X _ref is a position command, 1 is a control unit, 2 is a disturbance force suppression unit, 3 is a controlled object whose transfer function is P(s), and X is the position of the controlled object 3 detected by a position detector. be.

A disturbance suppression control device 4 of the present embodiment includes a control section 1 and a disturbance force suppression section 2 . A subtractor 6 of the control unit 1 subtracts the position feedback information X of the controlled object 3 from the position command X _ref to calculate the position deviation. Based on the positional deviation input via the subtractor 6, the control unit 1 outputs a force command f _ref (thrust force command or torque command) so as to reduce the positional deviation.

The disturbance force suppression unit 2 inputs the position feedback information X of the controlled object 3 to the inverse system 7 (P^ ^-1 (s)) of the nominal model P^(s) of the controlled object 3 to calculate the force f^. . The nominal model P̂(s) is an idealized model of the controlled object P(s), which is a driving mechanism including a motor. The inverse system 7 is P̂ ⁻¹ (s) that satisfies P̂(s)·P̂ ⁻¹ (s)=1 for the nominal model P̂(s). s is the Laplacian operator.

For example, if the controlled object P(s) is 1/Ms ² of the rigid body model, P̂ ⁻¹ (s) is Ms ² . P̂ ^-1 (s) is obtained by second-order differentiating the input position feedback information X to calculate the acceleration, and multiplying this by the mass M to calculate the inertial force.

A subtractor 8 derives the force command f _ref force from the extraction point 10 and subtracts the force f ̂ output by P̂ ⁻¹ (s) from the force command f _ref to calculate the force deviation e.

The disturbance force suppression unit 2 inputs the force deviation e to a low-pass filter, multiplies the output of the low-pass filter by a proportional gain K, and calculates a correction amount u. 9 is a low-pass filter and proportional gain block.

ここで、τはローパスフィルタの時定数、ｓはラプラス演算子である。 A transfer function of the low-pass filter and the proportional gain is represented by Equation (1).

where τ is the time constant of the low-pass filter and s is the Laplace operator.

Differentiation is required when P̂ ^-1 (s) calculates the force f̂, and noise is generated at the time of differentiation. By inputting the force deviation e to a low-pass filter, noise generated during differentiation can be reduced.

In addition, Formula 2 can also be used instead of Formula 1.

Using a low pass filter will lag the phase. Using Equation 2, the phase can be advanced. Equation 2 becomes a constant K if a=K.

The adder 11 of the disturbance force suppression unit 2 adds the correction amount u to the force command f _ref . The addition point (adder 11) is located after the extraction point 10 from which the disturbance force suppression unit 2 extracts the force command f _ref . That is, after the disturbance force suppression unit 2 derives the force command f _ref , the disturbance force suppression unit 2 adds the correction amount u to the force command f _ref . Note that the subtractor 8 may subtract the correction amount u from the force command f _ref depending on the sign of the disturbance force f _d or the like.

The force command f _ref output by the control unit 1 becomes f _ref +u+f _d after receiving the correction amount u and the disturbance force f _d . The output X becomes P(s)(f _ref +u+f _d ).

According to the disturbance suppression control device of this embodiment, the following effects are obtained. A force control feedback loop can be formed to suppress disturbance forces. By adjusting the correction amount with the proportional gain of this feedback loop, the disturbance suppression capability can be enhanced.

Since two parameters, the proportional gain K and the time constant τ of the low-pass filter, can be adjusted, various adjustments can be made, and the reverse response to the positional deviation after disturbance suppression can be prevented. For example, it is possible to make the reverse response (positional deviation in the negative direction) less likely to occur in the positional deviation after the occurrence of the quadrant protrusion. The effect of reducing the reverse response will be described later.
(Second embodiment)

FIG. 2 is a block diagram of a disturbance suppression control device 14 according to a second embodiment of the invention. In the second embodiment, the force f^ calculated by inputting the position feedback information X to the inverse system 7 (P^ ^-1 (s)) of the nominal model is multiplied by the feedback gain β in the block 21. It differs from the first embodiment. A subtractor 8 calculates a force deviation e by subtracting _βf̂ obtained by multiplying the force f̂ by the feedback gain β from the force command fref. Since other configurations are the same as those of the first embodiment, the same reference numerals are given and the description thereof is omitted.

According to the disturbance suppression control device 14 of the second embodiment, in addition to the same effect as the disturbance suppression control device 4 of the first embodiment, the feedback gain β can also be adjusted, so that the disturbance suppression capability can be further increased. can be done. For example, the quadrant projection amplitude can be reduced. The effect of reducing the amplitude of the quadrant protrusion will be described later.
(Third embodiment)

FIG. 3 is a block diagram of a disturbance suppression control device 31 according to a third embodiment of the invention. In the disturbance suppression control device 31 of the third embodiment, the controlled object 22 is a rigid body model represented by a transfer function P(s) ⁼ M/s2. M is the mass to be controlled. Then, input to the inverse system 24 (P^ ^-1 (s)) of the nominal model to calculate the force f^ (that is, calculate the acceleration by second-order differentiation of the position feedback information X, and use this acceleration as the control object is multiplied by the mass M to calculate the inertia force f^), and the inertia force f^ is multiplied by the feedback gain β.

In block 23, the velocity is calculated by differentiating the position feedback information X to the first degree. This velocity is multiplied by the mass M of the object to be controlled to calculate the frictional force g^. It is multiplied by a gain γ.

Adder 26 adds βf̂ and γĝ. A subtractor 8 subtracts the added value βf̂+γĝ from the force command f _ref to calculate the force deviation e. Since other configurations are the same as those of the first embodiment, the same reference numerals are given and the description thereof is omitted.

According to the disturbance suppression control device 31 of the third embodiment, the same effects as those of the disturbance suppression control device 4 of the first embodiment and the disturbance suppression control device 14 of the second embodiment are obtained. is calculated, the disturbance suppression capability can be further enhanced.
(Control system using the disturbance suppression control device of the present embodiment)

Using an example of a control system in which objects to be controlled are a linear motor and a stage, the effect of reducing quadrant projections of the disturbance suppression control device of this embodiment will be described below.

FIG. 4 shows the configuration of the drive system of the control system 40. As shown in FIG. 4 is a disturbance suppression control device, 46 is a servo amplifier, and 43 is a stage. The disturbance suppression control device 4 is composed of a computer such as a personal computer or a digital servo circuit, and includes a processor, a ROM, a RAM, and the like.

The disturbance suppression control device 4 includes a control unit 1 (see FIG. 1), receives a position command from a host device, performs position control and speed control of the stage 43, and outputs a thrust command (current command).

The servo amplifier 46 is composed of a transistor inverter or the like. The servo amplifier 46 receives a thrust command (current command) output by the disturbance suppression control device 4 and supplies power to the linear motor 44 according to the current command.

The linear motor 44 includes a stator 44b having magnets and a mover 44a having coils. When electric power is supplied to the coil of the mover 44a, an axial thrust force is generated on the table 41 of the stage 43. As shown in FIG. The position of table 41 is detected by position detector 47 . A signal from the position detector 47 is taken into the disturbance suppression control device 4 as position feedback information.

The stage 43 includes a base 48 , a table 41 movable with respect to the base 48 , and a linear guide 42 that guides movement of the table 41 .

The linear guide 42 has rolling elements such as balls or rollers interposed between a rail 42a and a guide block 42b so that the rolling elements circulate.

It is known that when an applied force is applied to the guide block 42b of the linear guide 42, the relationship between the applied force and the resulting displacement produces hysteresis and exhibits nonlinearity. Non-linear spring characteristics appear when the rolling elements in the guide block 42b start rolling or reverse their rolling direction. A frictional force caused by the nonlinear spring characteristics of the linear guide 42 acts on the stage 43 as a disturbance force. This disturbance force acting on the stage 43 causes a quadrant projection. A quadrant protrusion is a protrusion-like positional deviation that occurs when switching between quadrants when circular motion is performed using the XY stage, for example, and a protrusion that occurs when changing direction when reciprocating motion is performed using the X stage. positional deviation.

FIG. 5(a) shows a block diagram of a control system 40 incorporating the disturbance suppression control device 4 of the first embodiment of the present invention. The control unit 1 includes a P-controlled position controller 51 and a PI-controlled speed controller 52 . A position controller 51 inputs a position command X _ref and position feedback information X and outputs a speed command V _ref . Kp is the position loop proportional gain. A speed controller 52 inputs speed feedback information V obtained by differentiating the speed command V _ref and the position feedback information X to the first order, and outputs a thrust force command f _ref . Kv is the _velocity loop proportional gain, Ti is the integration time, and s and 1/s are the differentiation and integration in the Laplace transform, respectively.

The transfer function P(s) of linear motor 44 and stage 43 is P(s)=1/ ^Ms2 . M is the mass of the moving part. The inverse system 7 of the nominal model of the controlled object is P^ ^-1 (s)= ^Ms2 .

In the block diagram shown in FIG. 5(a), the equivalent transformation of the disturbance force suppression unit 2 as shown in FIG. 6(b) is performed. FIG. 6(a) shows a block diagram of the disturbance force suppression unit 2 before equivalent conversion, and FIG. 6(b) shows a block diagram of the disturbance force suppression unit 2 after equivalent conversion.

In the block diagram shown in FIG. 5(a), the addition point of the disturbance force _fd is in the thrust dimension. As shown in FIG. 5(b), when the addition point of the disturbance force fd is moved to the dimension of position, the transfer function of the position deviation _d due to the disturbance force _fd can be expressed by Equation (3).

数３を変形すると、数４が得られる。

Transformation of Equation 3 yields Equation 4.

On the other hand, the equation for generating the positional deviation (quadrant projection) without correction of the disturbance force is expressed by Equation (5).

ここで、τ_ｏｂｓは外乱オブザーバのローパスフィルタの時定数である。 Assuming that the _first term on the right side of Equation 4 is d1 and the _second term on the right side is d2, d1 is the differential value of the quadrant projection (quadrant projection generated without correction) in Equation 5, τ/(K+ ₁ ) is approximately equal to the product multiplied by Ignoring the influence of the first-order lag system, i.e., 1/(τs/(K+1)+1)= ₁ , d1 is equal to multiplying the differential value of the quadrant protrusion in Equation 5 by τ/(K+1). This _d1 has the same shape as the quadrant protrusion generated after correction by the disturbance observer. Since it is a differential value, _a reverse response (a positional deviation with a reverse sign) is generated after the quadrant projection occurs even in the quadrant projection generated after correction by the disturbance observer in d1. The quadrant protrusion d _obs generated after correction by the disturbance observer is given by Equation 5-1.

where τ _obs is the time constant of the low-pass filter of the disturbance observer.

d2 is approximately equal to the quadrant protrusion (quadrant protrusion generated without correction) of Equation ₅ multiplied by 1/(K+1), and is equal if the influence of the first-order lag system is ignored as described above. By adding this _d2 to d1, it is possible to reduce the _inverse response (the positional deviation of the inverse sign). The effect of reducing the reverse response will be described in the first embodiment. If τ/(K+ ₁ ) is kept constant and K is increased, _only d2 becomes smaller and d1 becomes dominant, approaching the same response as the disturbance observer.

FIG. 7(a) shows a block diagram of a control system 40 incorporating the disturbance suppression control device 14 of the second embodiment of the present invention. The disturbance suppression control device 14 includes a control section 1 and a disturbance force suppression section 2 . Similar to the disturbance suppression control device 4 shown in FIG. 5A, the control unit 1 includes a P-controlled position controller 51 and a PI-controlled speed controller 52 . Kp is the position loop proportional gain, Kv is the _velocity loop proportional gain, and Ti is the integration time. s and 1/s are differential and integral in Laplace transform, respectively.

The disturbance force suppression unit 2 includes an inverse system 7 of the nominal model, like the disturbance suppression control device 4 shown in FIG. 5(a). τ is the time constant of the low-pass filter, K is the proportional gain, and β is the feedback gain.

In the block diagram shown in FIG. 7(a), the addition point of the disturbance force _fd is in the thrust dimension. As shown in FIG. 7B, when the addition point of the disturbance force fd is moved to the position dimension, the transfer function of the position deviation _d due to the disturbance force _fd can be expressed by the same equation as Equation 3 above. can. The feedback gain β is not included in the transfer function of the positional deviation d. The positional deviation _d due to the disturbance force fd can be expressed by the same equation as Equation 4 above. The feedback gain β is not included in Equation (4).
(Effect of reducing quadrant protrusion and reverse response)

A positional deviation (quadrant projection) was simulated using the transfer function of Equation 4. Equation 6 of the friction force model was used for the friction force (disturbance force f _d ) of the linear guide.

ここで、ｔは時間、ｔ_ｎｓｂは摩擦力モデルの時定数である。

where t is time and t _nsb is the time constant of the friction force model.

FIG. 8(a) shows the friction force. The frictional force suddenly increases when the direction of the stage 43 is reversed (at time 0), and approaches a constant value as time elapses.

FIG. 8(b) shows a quadrant projection that occurs without disturbance force correction. It can be seen that a quadrant protrusion of about 4.8 nm is generated immediately after the direction of the stage 43 is reversed.

FIG. 8(c) shows quadrant projections generated after correction by the disturbance suppression control device 4 of the present embodiment. Here, τ and K are adjusted so that the reverse response after the generation of the quadrant projection is minimized. It can be seen that the correction can significantly reduce the amplitude of the quadrant protrusion. _In addition, although _an inverse response ir occurred in d1 after the quadrant projection occurred, it can be seen that the _inverse response ir of d1 can be substantially eliminated by adding d2.

Using the control system 40 shown in FIG. 4, the stage 43 was operated with a sinusoidal command operation pattern (amplitude 1 mm, frequency 0.1 Hz), and the positional deviation was measured. FIG. 9 shows the position deviation (quadrant protrusion) that occurs without disturbance force correction. The dashed-dotted line in FIG. 9 indicates the sine wave command, and the solid line in FIG. 9 indicates the positional deviation. A quadrant protrusion 54 was generated each time the direction of the stage 43 was reversed, and the amplitude of the quadrant protrusion 54 was about 150 nm.

FIG. 10 shows quadrant projections generated after correction by the disturbance suppression control device 14 of this embodiment. The dashed line in FIG. 10 indicates the quadrant protrusion generated after correction by the conventional disturbance observer, and the dashed line in FIG. 10 indicates the quadrant protrusion (β=1 ), and the solid line in FIG. 10 indicates the quadrant protrusion (when β=0.6) generated after correction by the disturbance suppression control device 14 of the present embodiment.

The disturbance observer was able to reduce the quadrant projection amplitude to about 7 nm. However, the inverse response ir occurred after the quadrant projection.

When β=1, τ and K were adjusted after reducing τ/(K+1) to the extent that the response did not oscillate. By this adjustment, the inverse response ir after the occurrence of the quadrant protrusion could be reduced to about 1/2 compared to the case of correcting with the disturbance observer. The amplitude of the quadrant protrusion itself was about 7 nm, and there was no significant difference from the correction with the disturbance observer.

When β=0.6, τ and K were adjusted in the same way as when β=1, and β was further adjusted to 0.6. By adjusting β to 0.6, it was possible to reduce the quadrant projections to about 5 nm, and also to significantly reduce the reverse response ir after the generation of the quadrant projections, making it substantially zero.
(How to adjust parameters τ, K, β)

The three parameters τ, K, β of the disturbance suppression control devices 4, 14, 31 of this embodiment are adjusted by the following procedure.

(1) Low-pass filter time constant τ
As described above, d1, which is the _first term on the right side of Equation 4, is the differential value of the positional deviation (quadrant protrusion) d that occurs when the disturbance force suppression unit 2 does not perform correction (that is, when no correction is performed). multiplied by τ/(K+1). Also, d2, which is the _second term on the right side of Equation 4, is equal to 1/(K+1) multiplied by the quadrant protrusion d that occurs without correction. The quadrant projection d is expressed as a function of time.

In d1, _an inverse response occurs at the time when the amplitude of quadrant projection d decreases. If d(T)>0 at the time T at which the reverse response reaches its maximum, the reverse response can be prevented from occurring if Equation 7 holds.

ここで、ｄは外乱力抑止部２が補正を行わない場合に生ずる位置偏差（象限突起）の時間関数であり、Ｔはｄの微分値である逆応答が最大となる時刻である。 Transforming Equation 7 yields Equation 8, which represents a guideline value for τ.

Here, d is the time function of the positional deviation (quadrant protrusion) that occurs when the disturbance force suppression unit 2 does not correct, and T is the time when the reverse response, which is the differential value of d, reaches its maximum.

In this embodiment, the reference value of τ was obtained from the time function of the quadrant protrusion 54 (see FIG. 9) generated without correction and its time differential value. In the time-differentiated waveform, the maximum value of the reverse response (the denominator on the right side of Equation 8) occurring around 2.5 s when the motion direction reverses is 1152 nm/s, and the position deviation at time T when the reverse response reaches its maximum ( The numerator on the right side) was −115 nm, so from Equation 8, τ≦115/1152≈0.1 s was obtained. Therefore, the standard value of τ is set to 0.09 s.

FIG. 11 shows the occurrence after correction when τ is set to 0.09 s, when it is set to 0.18 s which is twice 0.09 s, and when it is set to 0.045 s which is half of 0.09 s. 10 is a graph comparing positional deviations (quadrant protrusions) obtained by No reverse response occurred when τ was set to 0.09 s. When τ was set to 0.18 s, a reverse response of about 0.2 nm was generated, but compared with the case of setting τ to 0.09 s, the quadrant protrusion could be reduced by about 2 nm. When τ was set to 0.045 s, although no reverse response occurred, the quadrant projections were about 3 nm larger than when τ was set to 0.09 s. It is also possible to change τ according to the presence or absence of the reverse response and the size of the quadrant protrusion after correction.

(2) Proportional gain K, feedback gain β
From Equation 4, the larger the proportional gain K is than 1, the smaller the positional deviation (quadrant projection) d can be made. Therefore, set K>1, preferably K>10. However, if the proportional gain K is too large, the response will oscillate. Therefore, the proportional gain K is adjusted so that the response does not oscillate.

Through experiments, it has been confirmed that d1, the _first term of Equation 4, is β times the quadrant protrusion d _obs when a disturbance observer is used. Therefore, 0<β<1 is set to reduce the positional deviation (quadrant protrusion) d.

The reason why d1, which is the first term of Equation 4, is β times the quadrant projection d _obs when using _a disturbance observer will be described below. The time constant τ/(1+βK) of the disturbance suppression control device 14 of this embodiment corresponds to the time constant τ _obs of the disturbance observer. When the time constant was adjusted until just before the oscillation of the response, the time constant τ _obs of the disturbance observer and the time constant τ/(1+βK) of the disturbance suppression control device 14 became substantially the same value. Therefore, τ _obs =τ/(1+βK).

When τ _obs =τ/(1+βK), Equation 9 holds if the conditions βK>>1 and 0<β<1 hold.

From d ₁ , Equation 5-1, and Equation 9, which are the first terms on the right side of Equation 4, it can be seen that d ₁ is β times smaller than the quadrant projection d _obs when the disturbance observer is used.

In this embodiment, K and β are set as follows. First, assuming that β ₌ 1, K is increased until just before the response oscillates, and the stability limit K is set to K0. The _K0 was 60.

FIG. 12(a) shows the position deviation (quadrant protrusion 55) when τ=0.09 s, β=1, and K=1. Although no reverse response occurred, quadrant projections 55 of about 100 nm were generated. FIG. 12(b) shows the position deviation when τ=0.09 s, β=1, and K=60. By increasing K, the quadrant protrusion 56 could be reduced to about 7 nm.

Next, β was made smaller than 1 and K was made larger so that βK=K ₀ , ie βK=60. FIG. 12(c) shows the position deviation when τ=0.09 s, β=0.4, and K=150. The quadrant projection 57 could be further reduced to about 2.5 nm.

In addition, the present invention is not limited to being embodied in the above-described embodiments, and can be embodied in other embodiments without changing the gist of the present invention.

For example, in the above embodiments, the controlled objects are the linear motor and the stage, but the controlled objects may be a rotating motor and a driving machine. Although the position information of the controlled object is used as the feedback information, the speed information of the controlled object can also be used.

In the above embodiment, the disturbance suppression control device is designed with the transfer function of the current control section set to "1", but the disturbance suppression control device can also be designed in consideration of the transfer function of the current control section.

In the above embodiment, the object to be controlled is a rigid body model, but the object to be controlled can also be a resonance model in which a mass and a spring are coupled.

The disturbance suppression control device of the present invention is suitable for high-resolution positioning devices such as semiconductor manufacturing equipment, liquid crystal manufacturing equipment, optoelectronic processing, machine tools, and three-dimensional modeling equipment (3D printers).

DESCRIPTION OF SYMBOLS 1... Control part 2... Disturbance force suppression part 3... Control object 4... Disturbance suppression control apparatus 7... Inverse system of nominal model of control object 9... Low-pass filter and gain block 10... Extraction point 11 Adder (addition point) 14 Disturbance suppression control device 21 Feedback gain block 31 Disturbance suppression control device f _ref Force command f^ Force e Force deviation τ Low-pass filter time constant, K...proportional gain, β...feedback gain, u...correction amount, _fd ...disturbance force

Claims (6)

a control unit that outputs a force command;
The feedback information of the controlled object is inputted to the inverse system of the nominal model of the controlled object to calculate the force, the force deviation is calculated based on the force command and the force, and the correction amount is calculated based on the force deviation and the proportional gain. and a disturbance force suppression unit that adds or subtracts the correction amount to or from the force command,
A disturbance suppression control device having an addition point or a subtraction point at which the disturbance force suppression section adds or subtracts the correction amount from the force command after a point at which the disturbance force suppression section extracts the force command. 2. The disturbance suppression control device according to claim 1, wherein the disturbance force suppression unit inputs the force deviation to a low-pass filter and multiplies the output of the low-pass filter by the proportional gain. 3. The disturbance suppression control device according to claim 1, wherein the disturbance force suppression unit multiplies the force calculated by inputting it to the inverse system of the nominal model by a feedback gain. 4. The disturbance suppression control device according to claim 1, wherein the proportional gain (K) is set to K>1. 3. The disturbance suppression control device according to claim 2, wherein the time constant τ of the low-pass filter is set to Equation 10 below.

Here, d is the time function of the position deviation that occurs when the disturbance force suppressing section does not correct, and T is the time when the reverse response, which is the time differential value of d, reaches its maximum. 4. The disturbance suppression control device according to claim 3, wherein the feedback gain ([beta]) is set to satisfy 0<[beta]<1.

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