JP3276533B2 - Fine positioning device with force feedback - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sub-micron-order positioning device using a piezo element or the like, which is a typical example of a displacement-generating actuator, and relates to a fine movement positioning device with force feedback which has a remarkable effect on shortening the positioning time. .

[0002]

2. Description of the Related Art In recent years, positioning accuracy on the order of submicrons has been required for minute positioning in fields such as precision machining, assembly and adjustment. In particular, in an ultra-precision positioning stage for exposing a fine pattern, a piezoelectric element or an electrostrictive element is frequently used as an actuator in order to realize a high resolution and a high frequency response band. FIG. 7 is a diagram illustrating a three-degree-of-freedom fine movement positioning device that performs positioning control of one vertical direction of translation and two degrees of inclination in a horizontal plane. This device is
The positioning control is performed by actuators 2M, 2R, and 2L that displace the flat substrate 1 in the vertical direction according to the applied voltage. Each of the actuators 2M, 2R, and 2L includes a piezo element as a driving element and a displacement magnifying mechanism for enlarging the displacement. Actuator 2
Position sensors 3M, 3R, 3L for measuring the displacement of the substrate 1 in the vertical direction are arranged near M, 2R, 2L. A mechanism including these components is called a fine movement positioning mechanism.

[0003] Displacement signals of the substrate 1 measured by the position sensors 3M, 3R, 3L are output to displacement amplifiers 4M, 4R, 4L.
L converts it into an electrical signal. The electric signal is compared with a command voltage applied to command voltage input terminals 5M, 5R, 5L and input to preamplifiers 6M, 6R, 6L,
Its output is input to programmable gain elements 7M, 7R, 7L that adjust the characteristics of the control loop. Then, the power amplifiers 8M, 8R, and 8L are excited with this output,
By moving the actuators 2M, 2R, 2L up and down,
Is driven to translate in the vertical direction or to tilt with respect to the vertical axis. The main closed loop related to these positions is called a feedback device, and includes a fine positioning mechanism and a feedback device, and is called a fine positioning device.

The power amplifiers 8M, 8R, 8L are of a type that outputs a current with respect to an input voltage. According to the configuration of such a feedback device, convergence to the steady-state error “zero” is guaranteed. This is because the piezo elements, which are components of the actuators 2M, 2R, 2L, are electrically capacitors, and include the current output type power amplifiers 8M, 8R, 8L and the piezo elements driven by them. The transfer function includes an integrator, and the so-called closed loop becomes a form 1, and according to the teaching of control theory, a steady-state error of "zero" is guaranteed.

[0005] As described above, the fine movement positioning mechanism is 3
Each axial feedback device is independent,
Further, the positioning time is reduced by making the gains of the programmable gain elements 7M, 7R, and 7L the same and sequentially increasing the gains. However, the increase in gain for shortening the positioning time is limited to a range that does not stimulate the dynamics of the mechanism in order to allow a margin in stability. In order to further increase the upper limit of such a gain, Japanese Patent Laid-Open Publication No. Hei 6-151272 ("Fine positioning device with acceleration feedback") adds an acceleration feedback device to the conventional position feedback device. A fine positioning device with acceleration feedback has been devised. Its effectiveness has been clarified theoretically and experimentally. In other known materials, how is the positioning control of the fine movement positioning mechanism using the piezoelectric element as the actuator configured? Japanese Patent Publication No. 7-1453 ("Control device for fine movement positioning device") discloses a position feedback device composed of a PI compensator and a feedforward compensator using a strain gauge attached to a displacement mechanism as a displacement sensor. ing. Japanese Patent Publication No. 7-1460 ("Displacement control mechanism using piezoelectric element") discloses a control device that performs state feedback by an observer by position detection using a displacement sensor. Further, JP-A-6-31
No. 0773 (“Driving Method of Piezoelectric Ceramic Actuator”) relates to a driving method of piezoelectric ceramics that reduces hysteresis generated in the characteristic between the amount of displacement and the voltage. A method for performing non-linear amplification is disclosed. In any case, the apparatus is configured to perform positioning by one closed loop system based on the sensor output of position detection.

[0006] As in the present invention, the configuration of the positioning device including force feedback as a minor loop to the position feedback device has not been disclosed yet.

[0007]

As described above, when the loop gain of the position feedback device in the fine movement positioning mechanism is increased, the responsiveness is sequentially increased. However, eventually, the dynamics of the mechanism itself are stimulated, and the improvement of responsiveness will level off. In order to further increase the responsiveness, it has been proposed to provide damping using an acceleration sensor. However, when interference such as mechanical collision is caused by mounting the acceleration sensor on the fine movement positioning mechanism, it cannot be mounted, of course. Therefore, it is inevitable to give up damping by acceleration feedback. Further, the acceleration sensor is very expensive, and it is asked whether the cost is appropriate for the improvement of the quick response obtained by providing the fine movement positioning mechanism with electric damping.

An object of the present invention is to improve the responsiveness of a fine positioning device by means of lower cost or means which does not cause mechanical interference in view of the problems of the prior art.

[0009]

According to the present invention, in order to achieve this object, in a fine positioning device, force feedback is included as a minor loop for position feedback instead of acceleration feedback.

[0010] More specifically, the first force member according to the present invention.
The fine movement positioning device with feedback includes a substrate to be positioned, an actuator including a piezo element for driving the substrate and a displacement magnifying mechanism, a position sensor for detecting the displacement of the substrate near the actuator, a preamplifier,
A programmable gain element, and a power amplifier of current output type, comparing the output of the position sensor with an external command voltage to obtain a deviation signal, based on the deviation signal, through a preamplifier and a programmable gain element. the current output type power amplifier excitation City, a feedback device for driving the actuator by the output current, the force sensor incorporated in the actuator, the force detector for converting the output of the force sensor into an electric signal, the force detection comprising a force compensator for applying a compensation to the output of the vessel, comprising a force feedback means for negatively feeding back the output of the force sensor to the input side of the current output type power amplifier via which the force Fidoba
Locking means depends on a preload applied to the piezo element.
DC voltage at the force detector that
So that the characterized that you have been configured.

Further, the second force feedback according to the present invention is provided.
The fine-movement positioning device with a lock includes a substrate to be positioned, an actuator including a piezo element for driving the substrate and a displacement magnifying mechanism, a position sensor for detecting displacement of the substrate near the actuator, a loop gain adjuster,
A PI compensator and a voltage output type power amplifier are provided. The output of the position sensor is compared with an external command voltage to obtain a deviation signal. Based on the deviation signal, a loop gain adjuster and a PI compensator are used. a voltage output type power amplifier <br/> excitation City Te, a feedback device for driving the actuator by the output voltage, a force sensor incorporated in the actuator, the force detection to convert the output of the force sensor into an electrical signal And a force compensator for compensating for the output of the force detector, and force feedback means via which the output of the force sensor is negatively fed back to the input side of the PI compensator.
The force feedback means is provided on the piezo element.
At the force detector, which occurs depending on the preload being applied.
A DC voltage to an equilibrium point, characterized that you have been configured. In this case, the numerator time constant of the PI compensator is
T ₁ , the first-order lag time constant of the voltage output type power amplifying means is T _d
Then, it is preferable that T ₁ = T _d .

[0012] In one embodiment of the present invention, the force compensator is an integrator.

In another embodiment of the present invention, the force compensator is a first-order lag filter. When the viscous friction coefficient of the positioning mechanism is D and the spring constant is K, the time constant of the first-order lag filter is Is D / K.

[0014]

According to another aspect, the present invention includes a displacement generating type actuator for displacing an object to be positioned, and position detecting means for detecting the position of the object, and the detected position is fed back. In a positioning device that positions the object by driving the actuator, a force detecting unit that detects a force generated when the actuator displaces the object,
And force feedback means for feeding back the force by damping when the object is displaced or compensating for imparting stiffness in addition thereto , wherein the force feedback means comprises:
The force generated depending on the preload applied to the eta
The DC voltage at the detection means is set to the equilibrium point.
And wherein the Tei Rukoto.

[0016]

According to the present invention, in a fine movement positioning mechanism using a displacement generating type actuator such as a piezo element, a force generated by the actuator is detected, and an electric signal is transmitted to the signal through a force compensator having an appropriate transfer function. , Negative feedback is provided to the front stage of the current output type power amplifier that drives the actuator. The manipulated variable at this time depends on how the transfer function of the force compensator is configured, but acts to increase the viscous term or increase the viscous term and the spring term. Accordingly, the frequency of the fine movement positioning mechanism can be shaped into a more stable mechanism. For this reason, when the position feedback is applied to the more stable fine movement positioning mechanism,
The loop gain of the position can be increased as compared with the conventional case, so that high responsiveness is achieved.

In a fine positioning mechanism for driving a displacement generating type actuator by exciting a voltage output type power amplifying unit with a signal via a PI compensating unit, a force is detected and an appropriate transfer function is applied to the signal. The electric signal via the force compensating means having a negative feedback is fed back to the preceding stage of the PI compensating means.
The amount of operation at this time also depends on the configuration of the transfer function of the force compensating means, but acts to increase the viscosity term or increase the viscosity term and the spring term as described above.

[0018]

FIG. 1 is a diagram showing a configuration of a fine movement positioning device with force feedback according to one embodiment of the present invention. The fine-movement positioning apparatus of this embodiment performs fine-movement positioning in three degrees of freedom as shown in FIG. 7, but in FIG. 1, only the portion of the actuator in the one-axis direction is enlarged in order to simplify the description. In addition, the configuration of a feedback device with force feedback in one axial direction is illustrated. In the figure, reference numeral 16 denotes a base which is a reference for displacing the substrate 1, and 19 denotes a displacement magnifying mechanism rigidly connected to the base 16. When the piezo element 20 is extended in the X direction, the extension displacement is transmitted to the elastic hinge having the notch 18b, and further, the protrusion of the displacement magnifying mechanism 19 having the notch 18a as a fulcrum via the force sensor 10, ie, The elastic hinge is rotationally displaced clockwise in the Y axis. As a result, since the protrusion is mechanically and rigidly connected to the substrate 1, the substrate 1 is displaced in the Z-axis direction. The output signal of the force sensor 10 is
It is converted into an electric signal by the force detector 11 and the force compensator 1
2 is input. The output signal of the force compensator 12 is negatively fed back to a stage preceding the current output type power amplifier 8. This loop is a minor or local force feedback for the positioning signal.

The main position feedback for this minor force feedback is constructed as follows.
The position sensor 3 is attached to the substrate 1, and the position sensor 3 observes a target 17 extending from the same rigid portion as the base 16 of the displacement magnifying mechanism 19. That is,
The displacement when the substrate 1 is shifted in the Z-axis direction with respect to the base 16 is measured. The output signal of the position sensor 3 is converted by the displacement amplifier 4 into an electric signal. Displacement amplifier 4
Is compared with the voltage applied to the command voltage input terminal 5 to become a deviation signal e. The deviation signal e is input to the preamplifier 6 and further to a programmable gain element 7 for adjusting the loop gain of the position. A signal obtained by adding the output signal of the programmable gain element 7 and the above-described negative feedback signal of the force feedback excites the current output type power amplifier 8 that drives the piezo element 20. Thereby, the substrate 1
Are positioned at a position corresponding to the voltage applied to the command voltage input terminal 5.

In the case of the fine positioning device with acceleration feedback disclosed in Japanese Patent Application Laid-Open No. 6-151272, an acceleration sensor is mounted on the substrate 1 to be precisely positioned among the mechanical elements constituting the fine positioning mechanism. I have to. However, there is a case where a fine movement positioning mechanism including the base 16 is mounted on an XY stage that moves over a long stroke in a horizontal plane, and at this time, a machine such as a collision caused by an acceleration sensor protruding from the substrate 1 is provided. Interference may occur. On the other hand, in the case of the present invention,
In the displacement transmission path from the actuator (piezo element) to the displacement magnifying mechanism and to the positioning board, Fig. 1
As described above, the force sensor 10 can be inserted between the displacement magnifying mechanism 19 and the positioning board 1. Therefore, occurrence of mechanical interference can be avoided.

The force sensors include metal resistance strain sensors, adhesive resistance strain sensors, non-adhesion resistance strain sensors, thin film resistance strain sensors, semiconductor strain sensors, piezoelectric force sensors, and magnetostrictive force sensors. An electromagnetic force sensor, an elastic vibration force sensor, an ultrasonic strain sensor, a surface acoustic wave force sensor, and the like are known. The force sensor is inexpensive as compared with the acceleration sensor, and is preferably used from the above for providing electric damping to the fine movement positioning mechanism or for providing damping and stiffness.

In general, a preload is applied to the piezoelectric element 20 by a preload applying mechanism (not shown) so that backlash does not occur. Although a DC voltage is generated in the force detector 11 depending on the adjustment, a force feedback is formed using the generated DC voltage as an equilibrium point.

Now, it will be analytically clarified that when the configuration of the fine movement positioning device with force feedback shown in FIG. 1 is adopted, the stable range with respect to the position loop gain is expanded. FIG. 2 is a block diagram illustrating a fine-motion positioning mechanism in the one-axis direction. The transfer function G _P (s) from the drive displacement x _d to the load displacement x is given by Equation 1.
Where M is mass, K is spring constant, D is viscous friction coefficient,
s is a Laplace operator.

[0024]

(Equation 1) Next, reference is made to the block diagram of force feedback in FIG. As shown in the figure, a force f is detected, and the detected force f is negatively fed back to a stage preceding the current output type power amplifier 8 via a transfer function 9 (G (s)) for force compensation. However, the transfer function 9 includes the force detector 11 and the force compensator 12 in FIG. In this case, the transfer function from input v _c of the current output type power amplifier 8 to the displacement x of the load is determined from the simple calculation as equation (2).

[0025]

(Equation 2) Here, when G (s) is expressed by Equation 3, T = D / K
Then, Equation 4 is obtained.

[0026]

(Equation 3)

[0027]

(Equation 4) When G (s) is selected as Expression 5 in Expression 1, the relationship of Expression 6 is obtained.

[0028]

(Equation 5)

[0029]

(Equation 6) In the case of Equation 4, it means that the electric viscous term by the force feedback is added to the viscous term of the fine movement positioning mechanism itself. Since the eigenvalue is set at the left back of the s plane, the loop gain can be increased when the position control is configured.
On the other hand, in the case of Equation 6, the viscous term and the spring term can be increased by the force feedback. Also in this case, the eigenvalue is set at the left back of the s plane. Therefore, when configuring the position control,
An increase in loop gain can be expected.

FIG. 4A is a control block diagram when the fine movement positioning mechanism in the one axis direction is driven by a current output type power amplifier. Equation (4) is expressed as shown in FIG. 4 (b), and equation (6) is expressed as shown in FIG. 4 (c).
FIG. 4A is a block diagram in which a current output type power amplifier 8 is connected to a first control target 13, and FIG. 4B is a block diagram illustrating a second control target 14 whose frequency is shaped by force feedback. FIG. 4 (c) is a block diagram in which a current output type power amplifier 8 is connected to a third control target 15 whose frequency is shaped by force feedback. Each figure is shown. FIGS. 5 and 6 illustrate the second control object 14.
And the third control target 15, the pole on the s plane (× in the figure)
It is a figure which shows arrangement | positioning of the zero point (circle mark in a figure) and zero point. For comparison, the arrangement of the poles and zeros of the first controlled object 13 without force feedback is also shown. The poles of the second controlled object 14 and the third controlled object 15 are both located at the far left of the s plane as compared to the case where no force feedback is provided. Therefore, as compared with FIG. 4A, in FIGS. 4B and 4C, the loop gain when the position control loop is formed can be increased. The meanings of the symbols used in FIGS. 4 to 6 are as follows.

[0031]

(Equation 7) Based on the above analysis, the extent to which the stability range regarding the loop gain of the position control system is expanded by applying force feedback can be obtained as follows from a simple calculation. However, the gain of the reference to K _s are included and the displacement sensor 3 the displacement amplifier 4 position detecting FIG 1,
K _loop means a gain including the preamplifier 6 and the programmable gain element 7.

[0032]

(Equation 8)

[0033]

(Equation 9)

[0034]

(Equation 10) Here, Equations 8, 9 and 10 mean that the closed loop system is always stable as long as the loop gain is positive. In the case of Expression 8, the controlled object without force feedback, that is, the original fine movement positioning mechanism has a high viscosity term, and the stability when the closed loop of the position is configured is sufficient. There is no necessity to add an effect by force feedback to such a fine movement positioning mechanism. That is, Equations 8, 9 and 10 are not significant as stability discriminants in the actual case. Referring to FIG. 1, it is generally impossible for a driving mechanism including the piezo element 20 and the displacement magnifying mechanism 19 made of a metal material to have high viscosity.
Actually, Equations 8, 9 and 10 are the stability determination equations for the actual fine movement positioning mechanism. Therefore, Equations 8 and 9 and Equations 8 and 10 are compared. When the force feedback is included as a minor loop with respect to the position feedback loop, it can be understood that the stable range of the position related loop gain is expanded.

Finally, the effectiveness of the fine positioning device with force feedback of FIG. 1 according to the present invention will be shown by numerical experiments. First, FIG. 8 shows a case where the transfer function 9 for force compensation is a first-order lag filter as shown in Expression 3, and shows a comparison of step responses depending on the presence or absence of the filter. In the figure, the broken line indicates the case where there is no force feedback.
This shows a case where the loop gain at the position is set to be large so as to provide an oscillating response. The response when force feedback is performed with the first-order lag filter given by Expression 3 having an appropriate gain while maintaining the loop gain at this position is a waveform indicated by a solid line A. Solid lines B and C are responses when the loop gain of the solid line A is normalized to 1 and 2 and 2.5, respectively.
Although the overshoot occurs as the loop gain increases, the positioning responsiveness can be improved.

FIG. 9 is a diagram showing a comparison of the step response depending on the presence or absence of the integrator as the transfer function 9 of the force compensation as shown in Equation 5. In the figure, the broken line indicates the case where there is no force feedback, and the position loop gain is set so as to provide an oscillating response. When the force feedback is constituted by the transfer function 9 of the force compensation of the integral characteristic having an appropriate integral gain while maintaining the loop gain, the response waveform becomes a solid line a. Solid lines b and c
Is a response when the loop gain of the solid line a is normalized to 1 and the loop gain is 2 and 2.5. Although it becomes oscillating according to the magnitude of the loop gain, the positioning stabilization is better than the response indicated by the broken line.

Table 1 shows physical parameters of the fine movement positioning mechanism used in these numerical experiments. The piezo element is a laminated type having a voltage displacement conversion constant of 1.3 × 10 ⁻⁷ [m / V].

[0038]

[Table 1]

[0039]

Other Embodiments In the above-described embodiment, the current output type power amplifier 8 is used for driving the piezo element 20. By selecting the voltage function G (s) of the force compensation as shown in Expression 3 or Expression 5 under the condition of driving the piezo element 20 with this type of power amplifier 8, position feedback is provided to the fine movement positioning mechanism. Immediate response and settling when applied can be improved. However, in general, the piezo element 2
0 is driven by the voltage output type power amplifier 8. Therefore, a configuration of a fine movement positioning device with force feedback based on the use of the voltage output type power amplifier 8 is provided. FIG. 10 is a block diagram showing a configuration of a fine movement positioning device with force feedback according to another embodiment of the present invention. In the figure, reference numeral 13 surrounded by a broken line denotes a first control object indicating the same part as the block diagram expressing the one-axis fine movement positioning mechanism shown in FIG. 2, reference numeral 21 denotes a voltage output type power amplifier,
22 is a PI compensator and 23 is a loop gain adjuster.
Here, P means a proportional operation, and I means an integral operation.

In FIG. 10, the output of the transfer function 9 for force compensation is negatively fed back to the preceding stage of the PI compensator 22. Here, the numerator time constant T ₁ of the PI compensator 22 is adjusted to be the same as the time constant T _d of the voltage output type power amplifier 21.
That is, T _d = T ₁ is selected, and the zero of the PI compensator 22 cancels the pole of the voltage output type power amplifier 21. At this time,
The transfer function from _vv to x is as shown in Equation 11.

[0041]

[Equation 11] Here, it should be noted that Expression 11 has the same structure as Expression 2. Therefore, the force compensation transfer function 9
Is selected as Expression 3 or Expression 5, referring to FIG. 10, the second control object 14 or the third control object surrounded by a broken line having improved stability as compared with the first control object 13. It is the target 15. Here, with respect to the second control object 14 or the third control object 15 to obtain a deviation signal e as compared with a voltage adding output of the gain K _s position detecting pointing at 24 to the command voltage input terminal 5, Further, the deviation signal e
_{Is made} to v _v through a loop gain adjuster 23 having a gain K _loop . Then, by adjusting the gain K _loop of the loop gain adjuster 23, the responsiveness can be improved as compared with the related art.

For the sake of simplicity, the fine positioning device with force feedback shown in FIGS. 1 and 2 is shown only in one axial direction. Of course, 3 in FIG.
The application of the present invention to not only the fine movement positioning mechanism having a degree of freedom but also the fine movement positioning mechanism having a plurality of degrees of freedom is not hindered without departing from the gist of the present invention. That is, FIG.
Alternatively, a feedback device for the position including the force feedback shown in FIG. 2 may be provided for each number of actuators. Further, in the embodiments of FIGS. 1 and 2, the control system is realized by an analog arithmetic circuit, but a part or all of the control system may be replaced by a digital arithmetic device such as an electronic computer.

[0043]

As described above, according to the present invention, by providing the force feedback means, the fine movement positioning mechanism incorporating the piezo element or the like, which is a displacement generating actuator, can be replaced by the current output type power amplifying means. When driving, force feedback is performed,
The viscosity term of the second-order denominator polynomial, or both the viscosity term and the spring term, can be increased.

Conventionally, when the position loop gain is sequentially increased, the positioning time can be reduced, but the dynamics of the fine movement positioning mechanism are gradually stimulated and the upper limit of the loop gain is suppressed. there were. However, according to the present invention, the dynamics of the fine movement positioning mechanism can be shifted to the stable side by the force feedback, so that the position loop gain can be set higher than before. That is, there is an effect that the positioning time can be shortened as compared with the related art.

Although the same effect can be achieved by configuring the minor feedback to the position using an acceleration sensor, in the present invention, the same effect can be obtained by using a force sensor which is less expensive than the acceleration sensor, so that the cost can be reduced. This is also advantageous.

Further, as compared with mounting the acceleration sensor on the substrate constituting the fine movement positioning mechanism, the incorporation of the force sensor into the fine movement positioning mechanism can be mounted on a portion where mechanical interference is unlikely to occur, and There is an effect that electric adjustment is easy.

[Brief description of the drawings]

FIG. 1 is a view showing a configuration of a fine movement positioning device with force feedback according to one embodiment of the present invention.

FIG. 2 is a block diagram illustrating a uniaxial fine movement positioning mechanism.

FIG. 3 is a block diagram of force feedback.

FIG. 4 is a control block diagram when the one-axis fine movement positioning mechanism is driven by a current output type power amplifier.

FIG. 5 is a diagram showing pole-zero point arrangements of a first controlled object and a second controlled object.

FIG. 6 is a diagram showing pole-zero point arrangements of a first controlled object and a third controlled object.

FIG. 7 is a view showing a configuration of a fine movement positioning device having three degrees of freedom according to a conventional example.

8 is a diagram comparing step responses depending on the presence or absence of a transfer function of force compensation in the apparatus of FIG. 1 when the transfer function is a first-order lag filter.

9 is a diagram comparing step responses depending on the presence or absence of an integrator as a transfer function for force compensation in the apparatus of FIG. 1;

FIG. 10 is a block diagram showing a configuration of a fine movement positioning device with force feedback according to another embodiment of the present invention.

[Explanation of symbols]

1: substrate, 2M, 2R, 2L: actuator such as piezoelectric element, 3, 3M, 3R, 3L: position sensor, 4, 4
M, 4R, 4L: displacement amplifier, 5, 5M, 5R, 5L:
Command voltage input terminal, e, e _M , e _R , e _L : deviation signal,
6, 6M, 6R, 6L: preamplifier, 7, 7M, 7R,
7L: programmable gain element, 8, 8M, 8R, 8
L: power amplifier, 9: transfer function of force compensation, 10: force sensor, 11: force detector, 12: force compensator, 13: first control target, 14: second control target, 15: third control target , 16 base, 17: target, 18a, 18b: notch, 19: displacement enlargement mechanism, 20: piezo element, 2
1: voltage output type power amplifier, 22: PI compensator, 23:
Loop gain adjuster, 24: position detection gain.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-151272 (JP, A) JP-A-60-259347 (JP, A) JP-A-64-44510 (JP, A) 154743 (JP, A) JP-A-5-134759 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G05D 3/00-3/20 G05B 11/00-13/04 H01L 21/68

Claims (6)

(57) [Claims] 1. A substrate to be positioned, an actuator comprising a piezo element for driving the substrate and a displacement magnifying mechanism; a position sensor for detecting the displacement of the substrate near the actuator; a preamplifier; Element, and a power amplifier of current output type, comparing the output of the position sensor with an external command voltage to obtain a deviation signal, based on the deviation signal, via the preamplifier and the programmable gain element. To excite the current output type power amplifier.
Electromotive City, a feedback device for driving the actuator by the output current, the force sensor incorporated into the actuator, the force detector for converting the output of said force sensor into an electrical signal, the output of said force detector comprising a force compensator for applying a compensation for, through which comprises a force feedback means for negatively feeding back the output of the force sensor to an input side of said current output type power amplifier, wherein the force feedback means, said Applied to the piezo element
DC at the force detector that is generated depending on the preload
As the voltage and equilibrium point, fine positioning device with force feedback, characterized that you have been configured. 2. A substrate to be positioned, an actuator comprising a piezo element for driving the substrate and a displacement magnifying mechanism; a position sensor for detecting the displacement of the substrate near the actuator; a loop gain adjuster; A compensator, and a voltage output type power amplifier. The output of the position sensor is compared with an external command voltage to obtain a deviation signal. Based on the deviation signal, the loop gain adjuster and the PI compensator are obtained. excitation City said voltage output type power amplifier through, to convert a feedback device for driving the actuator by its output voltage, a force sensor incorporated into the actuator, the output of said force sensor into an electrical signal A force detector for compensating an output of the force detector, and the force sensor via the force compensator. Feedback means for negatively feeding back the output of the PI compensator to the input side of the PI compensator.
And the force feedback means is applied to the piezo element.
DC at the force detector that is generated depending on the preload
As the voltage and equilibrium point, fine positioning device with force feedback, characterized that you have been configured. 3. The fine positioning device with force feedback according to claim 1, wherein the force compensator is an integrator. 4. The time compensator is a first-order lag filter, and when the viscous friction coefficient of the positioning mechanism is D and the spring constant is K, the time constant of the first-order lag filter is D / K. The fine positioning device with force feedback according to claim 1 or 2, wherein: 5. When the numerator time constant of the PI compensator is T ₁ and the first-order lag time constant of the voltage output type power amplifying means is T _d , T ₁ = T _d. The fine positioning device with force feedback according to claim 2. 6. A displacement generating type actuator for displacing a positioning target object, and a position detecting means for detecting a position of the target object, wherein the detected position is fed back to drive the actuator to thereby detect the target object. In a positioning device for positioning, force detecting means for detecting a force generated when the actuator displaces the object, and damping or applying stiffness in addition to damping the force when the object is displaced. Force feedback means for performing compensation and feedback of the force , wherein the force feedback means is provided on the actuator.
The force detecting means generated depending on the preload being applied
As the DC voltage to an equilibrium point, the positioning device characterized that you have been configured.