JPH06752A - Positioning control method and device - Google Patents

Abstract

PURPOSE:To perform stable and high-precise positioning of a high movement amount without being influenced by disturbance even when disturbance occurs. CONSTITUTION:A control method and a device wherein a correction signal R matching with distance is inputted to a micromovement compensating command signal E for a micromovement mechanism 2, incapable of absorbing disturbance, of a positioning control system comprising a system related to a coarse movement mechanism 1 and a system related to the micromovement mechanism 2 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning control method and device, and is useful when applied to a positioning device and a moving device that require highly accurate positioning with a large amount of movement.

[0002]

2. Description of the Related Art FIG. 8 is a block diagram showing a control device according to a prior art in a positioning device for positioning a large movement amount with high accuracy by combining a coarse movement mechanism and a fine movement mechanism. In FIG. 8, a signal generator 104 generates a movement command signal A5 for positioning and is composed of a computer or an analog circuit. The absolute position detection means 105 is a sensor formed of, for example, a laser interferometer, detects an absolute displacement amount H5 of a positioning target, and outputs a displacement signal B5. Relative position detection means 1
Reference numeral 03 denotes a sensor formed of, for example, a capacitance type displacement meter, which detects a relative displacement of the fine movement mechanism 102 with respect to the coarse movement mechanism 101, and outputs the output signal K5 to the control calculation unit 108. The control calculation unit 108, which has an adjustable gain and frequency characteristic, such as an integrator, sends an output signal L5.

On the other hand, the coarse movement mechanism 101, as a drive source,
For example, an actuator such as a DC servo motor or a stepping motor is used, and rolling or friction is used as a guide element. The response speed is relatively slow, the positioning accuracy is relatively low, but the movement amount is large. There is.
The coarse motion mechanism 101 moves by a coarse motion displacement amount F5 based on a coarse motion compensation command signal D5 which is an output signal of the coarse motion compensation circuit 106. The coarse motion compensation circuit 106 uses the movement command signal A5.
The coarse motion compensation command signal D5 is generated based on the coarse motion command signal M5 generated by adding the output signal L5 based on the relative displacement amount G5 to the deviation signal C5 including the displacement signal B5.

On the other hand, the fine movement mechanism 102 uses a actuator such as a piezoelectric element or a magnetostrictive element, which can respond at high speed and has a high displacement resolution and has a large generated force as a driving source, and uses, for example, a hinge spring or a plate as a guide element. It uses a spring or the like and has a high response speed and high positioning accuracy, but the amount of movement is small, about several tens of μm. The fine movement mechanism 102 moves by a relative displacement amount G5 based on a fine movement compensation command signal E5 which is an output signal of the fine movement compensation circuit 107. Fine motion compensation circuit 107
Is the fine movement compensation command signal E based on the deviation signal C5.
5 is generated.

According to such a conventional method, the displacement signal B5 is subtracted from the movement command signal A5 to generate the deviation signal C5, and the deviation signal C5 is directly output to the fine motion compensation circuit 107 and an output signal based on the relative displacement amount G5. Is added to the coarse motion compensation circuit 106 side by adding L5. That is, the deviation signal C5 supplied to the coarse motion compensation circuit 106 side
Is added to the output signal L5 based on the output signal K5 from the relative position detection means 103 for detecting the relative displacement amount G5 of the fine movement mechanism 102 with respect to the coarse movement mechanism 101 to generate the coarse movement movement command signal M5 (= C5 + L5). After that, the coarse movement movement designation signal M5 passes through the coarse movement compensation circuit 106 to generate the coarse movement compensation command signal D5.

On the other hand, the deviation signal C5 sent to the fine movement compensating circuit 107 generates a fine movement compensating command signal E5 after passing through the fine movement compensating circuit 107. Thus, the coarse movement mechanism 10 is controlled by the coarse movement compensation command signal D5 and the fine movement compensation command signal E5.
1 and the fine movement mechanism 102 are moved by the coarse movement displacement F5 and the relative displacement G5, respectively.

The coarse movement mechanism 101 has a coarse movement compensation command signal D5.
In response to the movement command signal A5, the coarse movement mechanism 10 always tries to move by the coarse movement displacement amount F5.
1 has poor accuracy, so movement command signal A5 and displacement signal B5
The deviation signal C5 obtained by subtracting and cannot be made to be zero, and the deviation that remains after complete positioning cannot be moved by the fine movement mechanism 102 by the relative movement amount G5 so that the absolute displacement amount H5 relative to the fixed position of the positioning target is H5. = F5 + G5, and a large amount of movement and high-precision positioning are performed. In this case, the absolute displacement amount H5 is detected by the absolute position detecting means 105, and the displacement signal B5 which is the detection signal at this time is converted into the signal generator 104.
The deviation signal C5 is generated by subtracting from the movement command signal A5 of (1) to perform closed feedback control.

Further, the relative position detecting means 1 detects the amount of fine movement displacement G5 accumulated as the fine movement mechanism 102 moves.
In 03, the relative displacement amount of the fine movement mechanism 102 and the coarse movement mechanism 101 is detected, the output signal K5 corresponding to this relative displacement amount is passed to the control calculation unit 108, and the signal L5 generated here is added to the deviation signal C5 to generate the result. The coarse movement command signal M5 is supplied to the coarse movement compensation circuit 106. As a result, the coarse movement compensation command signal D5 generated causes the coarse movement mechanism 101 to move. Therefore, the coarse movement mechanism 101 always observes the fine movement displacement amount G5 and moves when the fine movement mechanism 102 reaches a certain specific displacement, and as a result, the fine movement mechanism 102 can always move within a certain specific range. Fine movement mechanism 102 at this time
The movable range is set by adjusting the gain of the control calculation unit 108. Thus, the fine movement mechanism 102 can always move within the movable range. With the above operation, positioning is performed with high accuracy over a long distance.

[0009]

Although a large amount of movement and high-precision positioning can be performed by the above-mentioned method, by using such a positioning control device, for example, a positioning target can be positioned over a wide range in the XY plane. In order to follow the target locus, it is necessary to combine conventional control devices with two or more axes for control. For that purpose, as shown in FIG. 7, two sets of conventional positioning control devices are combined to form an XY biaxial control device. In such cases,
Positioning accuracy deteriorates at the same time due to an assembly error or a displacement amount not caused by the movement command signal A5 such as inter-axis interference in which a displacement is generated in the Y axis which is orthogonal even though the movement command signal A5 is added to the X axis. There was a problem such as the control system oscillating. Further, a displacement amount not caused by the movement command signal A5 is generated even when a disturbance such as vibration, impact, or temperature change is applied to the positioning target, and similarly, the positioning accuracy may be deteriorated and the control system may be oscillated.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is a control that suppresses the displacement of the controlled object that is not caused by the movement command signal and that follows the positioning object with high accuracy and stability. It is an object of the present invention to provide a positioning control method and device capable of performing the above.

[0011]

The structure of the present invention which achieves the above object is (1) a coarse movement mechanism having a large movement amount but low positioning accuracy, and a fine movement mechanism having a small movement amount but high positioning accuracy. In the positioning control method for controlling the position of the positioning target mounted on the fine movement mechanism of the moving device consisting of, a deviation signal composed of the difference between the displacement amount signal and the movement command signal, which represents the displacement amount of the positioning target with respect to the fixed position, ,
A coarse movement movement command signal is generated in addition to the relative displacement amount of the fine movement mechanism with respect to the coarse movement mechanism, the coarse movement movement command signal is input to the coarse movement mechanism, and the fine movement composed of the difference between the deviation signal and the relative displacement amount is generated. A command signal is generated, a correction signal is further generated from a displacement amount of the controlled object that is not caused by the movement command signal, and a signal including a difference between the fine motion command signal and the correction signal is input to the fine motion mechanism, 2) Further, in a positioning control device mounted on the fine movement mechanism of a moving device including a coarse movement mechanism having a large movement amount but low positioning accuracy and a fine movement mechanism having a small movement amount but high positioning accuracy, A signal generator for generating a movement command signal for a positioning object, and an absolute position detecting means for detecting an absolute position of the positioning object with respect to a fixed position and transmitting a displacement signal representing a displacement amount at this time. A relative position detection means for detecting a relative displacement amount of the fine movement mechanism with respect to the coarse movement mechanism, a means for outputting a correction signal from the relative displacement amount generated in the positioning target, and the movement command signal and the displacement signal. Means for outputting a deviation signal indicating a difference, means for outputting a fine movement command signal indicating a difference between the deviation signal and the relative position detecting means, and a fine movement correction instruction indicating a difference between the fine movement command signal and the correction signal The fine movement mechanism is controlled based on a signal, and the coarse movement mechanism is controlled based on a coarse movement command signal obtained by adding an output signal of the relative position detecting means to the deviation signal.

[0012]

According to the present invention, even if a displacement amount of the controlled object that is not caused by the movement command signal is generated, a means for generating a correction signal from the displacement amount is additionally provided. By inputting a signal consisting of the signal difference to the fine movement mechanism, it is possible to suppress the amount of displacement of the controlled object that is not caused by the movement command signal.

[0013]

EXAMPLES Examples of the present invention will now be described with reference to FIGS. FIG. 1 is a block diagram of an embodiment corresponding to prior art FIG. A signal generator 4 shown in the figure generates a movement command signal A for positioning, and is composed of a computer or an analog circuit. The absolute position detecting means 5 is, for example, a sensor formed by a laser interferometer, detects an absolute position based on an absolute displacement amount H which is a displacement of a positioning target with respect to a fixed position, and a displacement signal B representing the displacement amount at this time. Is output. The relative position detecting means 3 is, for example, a sensor formed of a capacitance type displacement gauge, detects the relative displacement of the fine movement mechanism 2 with respect to the coarse movement mechanism 1, and supplies the output signal K thereof to the control calculation section 8. The control calculator 8 adjusts the gain and frequency characteristics like an integrator, and sends an output signal L.

The coarse movement mechanism 1 uses, for example, DC as a drive source.
For example, an actuator such as a servo motor or a stepping motor is used, and rolling or friction is used as a guide element. The response speed is relatively slow, the positioning accuracy is relatively low, but the amount of movement is large. The coarse motion mechanism 1 moves by a coarse motion displacement amount F based on a coarse motion compensation command signal D which is an output signal of the coarse motion compensation circuit 6. The coarse motion compensation circuit 6 detects a deviation signal C between the movement command signal A and the displacement signal B.
In addition, the coarse motion compensation command signal D is generated based on the coarse motion movement command signal M generated by adding the output signal L based on the relative displacement amount G.

The fine movement mechanism 2 uses an actuator such as a piezoelectric element or a magnetostrictive element capable of high-speed response as a drive source and having a high displacement resolution and a large generated force, and a guide element such as a hinge spring or a leaf spring. Although the response speed is fast and the positioning accuracy is high, the movement amount is small, about several tens of μm. The displacement amount of the fine movement mechanism with respect to the coarse movement mechanism when the fine movement mechanism 2 moves is the relative displacement amount G.

In the above-mentioned structure, the present embodiment adopts a structure in which a correcting means for disturbance or the like is added. That is,
The relative position detecting means output signal K obtained based on the relative displacement amount G is subtracted from the deviation signal C to obtain a fine movement command signal N to the fine movement compensating circuit 7. Further, the relative position detecting means 3 is connected to the calculating means 21, and the calculating means 21
Then, the fine displacement signal P is obtained. The filter 22 is, for example, a low-pass filter and removes a noise component from the fine movement correction signal Q obtained by subtracting the fine movement correction command signal S from the fine movement displacement signal P to obtain the correction signal R. Then, the correction signal R output from the filter 22 is subtracted from the fine movement compensation instruction signal E to obtain the fine movement correction instruction signal S. Thus, the fine motion compensation command signal S obtained by subtracting the correction signal R from the fine motion compensation command signal E
The fine movement mechanism 2 moves based on.

Here, FIG. 1 will be described in more detail in view of a state in which a disturbance is applied. When vibration, shock, temperature change, or disturbance such as inter-axis interference that occurs when the positioning device is multi-axised is applied to the coarse movement mechanism 1 and the fine movement mechanism 2,
Due to the influence of this disturbance, a displacement amount that is not caused by the coarse motion compensation command signal D and the fine motion compensation command signal E is generated, so that a positioning error occurs in the absolute position amount H. In this case, of the displacement amounts caused by the disturbance, the displacement amount not caused by the coarse motion compensation command signal D is configured such that the fine movement mechanism 2 is mounted on the coarse movement mechanism 1 in the present positioning device. The fine movement mechanism 2 absorbs the amount of displacement that is not caused by the coarse movement compensation signal D, and there is no problem. On the other hand, since the positioning device is not configured to absorb the displacement amount that is not caused by the fine movement compensation command signal E, the displacement amount that is not caused by the fine movement compensation command signal E remains in the fine movement mechanism 2. .

FIG. 2 shows the flow of input / output signals in the fine movement mechanism 2 when a disturbance T is applied. As shown in FIG. 2, when the disturbance T is applied, the fine movement input signal U becomes a signal obtained by adding the disturbance T to the fine movement compensation command signal E. By inputting such a fine movement input signal U to the fine movement mechanism 2, the fine movement mechanism 2 moves by the relative displacement amount G. At this time, the relative displacement amount G includes the disturbance T not caused by the fine movement compensation command signal E.
The displacement amount due to is included. Therefore, as shown in FIG. 3, if the correction signal R for canceling the disturbance T is subtracted from the fine movement compensation command signal E in advance and the signal obtained as a result is set as the fine movement correction signal S, the disturbance T is converted into the fine movement correction signal S. , The correction signal R and the disturbance T cancel each other, so that the generated fine movement input signal U does not include the disturbance T. Therefore, the relative displacement amount G resulting from the input of the fine movement input signal U to the fine movement mechanism 2 does not include the displacement amount which is not caused by the fine movement compensation command signal E.

The process of deriving the correction signal R will be described with reference to FIG. First, the fine movement input signal U is S + T
Then, it is input to the fine movement mechanism 2 and moved by the relative displacement amount G. The relative displacement amount G at this time is detected by the relative position detecting means 3, and the relative position detecting means output K is obtained. Here, the output K of the relative position detecting means is K = αU = α (S + by passing through the fine movement mechanism 2 and the relative position detecting means 3.
T). Note that α is an arbitrary coefficient determined by the characteristics of the fine movement mechanism 2 and the relative position detection means 3. Here, the calculating means 21 has a function of multiplying the input signal by 1 / α, and when the relative position detecting means output K is input to the calculating means 21, the fine movement displacement signal P which is the output signal thereof is P
= S + T. Further, if the fine movement correction command signal S is subtracted from the fine movement displacement signal P as shown in FIG. 4, the fine movement correction signal Q generated as a result is: Q = P-S = (S + T) -S = T Becomes

Next, noise such as power supply noise contained in the fine movement correction signal Q is passed through the filter 22,
The correction signal R is obtained by damping or blocking. The correction signal R is obtained by removing only the noise component from the fine movement correction signal Q, and is basically equal to the fine movement correction signal Q. Therefore, the correction signal R is R = T.

When the correction signal R obtained as described above is subtracted from the fine motion compensation command signal E in advance, the fine motion correction command signal S becomes S = ER. Next, since the disturbance T is added to the fine movement correction command signal S, the fine movement input signal U is U = S + T =
It becomes ER + T. Here, as described above, since R = T, U = E, and the fine movement mechanism 2 does not generate a displacement amount that is not caused by the fine movement compensation command signal E.

FIG. 5 is a graph showing the displacement amount of the positioning target when a disturbance is applied to the positioning target in the conventional control method. Referring to the figure, it can be seen that a displacement amount of 30 nm is generated. On the other hand, in the method according to the present embodiment of FIG. 6, the displacement amount of the positioning target is 2 nm even when the same disturbance as in FIG. 5 is applied, and according to the present embodiment, the displacement of the positioning target caused by the disturbance is It can be seen that the amount is suppressed.

[0023]

As described above in detail with reference to the embodiments, according to the control of the present invention, even if a displacement such as a disturbance that is not caused by a movement command signal is applied to the controlled object, it is suppressed. Therefore, it is possible to position a wide range with high accuracy and stability.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a flow of input / output signals in the fine movement mechanism.

FIG. 3 is a block diagram showing the principle of controlling disturbance.

FIG. 4 is a block diagram showing a control method of a fine movement mechanism based on the embodiment.

FIG. 5 is a graph showing a displacement amount when a disturbance is applied to a controlled object when a conventional control method is applied.

FIG. 6 is a graph showing a displacement amount when a disturbance is applied to a controlled object when the control method in the example of the present invention is applied.

FIG. 7 is a conceptual diagram in the case of controlling the XY plane by combining conventional control methods.

FIG. 8 is a block diagram showing a positioning control device according to a conventional technique.

[Description of symbols] 1 coarse movement mechanism 2 fine movement mechanism 3 relative position detection means 4 signal generator 5 absolute position detection means 6 coarse movement compensation circuit 7 fine movement compensation circuit 8 control calculation unit 21 calculation means 22 filter A movement command signal B displacement Signal C Deviation signal D Coarse motion compensation command signal E Fine motion compensation command signal F Coarse motion displacement amount G Relative displacement amount H Absolute displacement amount K Relative position detection means output signal L Control calculation unit output signal M Coarse movement command signal N Fine motion command signal P fine movement displacement signal Q fine movement correction signal R correction signal S fine movement correction command signal T disturbance U fine movement input signal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nobu Shin Asano, 1-8, Koura, Kanazawa-ku, Yokohama-shi, Kanagawa Mitsubishi Heavy Industries, Ltd. Basic Technology Research Institute (72) Inventor, Satoshi Tahara, 1-chome, Koura, Kanazawa-ku, Yokohama, Kanagawa Address 1 Mitsubishi Heavy Industries, Ltd. Basic Technology Research Laboratory

Claims (2)

[Claims] 1. A position of a positioning object mounted on the fine movement mechanism of a moving device comprising a coarse movement mechanism having a large movement amount but a low positioning precision and a fine movement mechanism having a small movement amount but a high positioning precision. In the positioning control method for controlling, the deviation signal, which is the difference between the displacement amount signal indicating the displacement amount of the positioning target with respect to the fixed position and the movement command signal, is added to the relative displacement amount of the fine movement mechanism with respect to the coarse movement mechanism to perform coarse movement. A command signal is generated and the coarse movement command signal is input to the coarse movement mechanism to generate a fine movement command signal composed of the difference between the deviation signal and the relative displacement amount, and further the displacement of the controlled object not caused by the movement command signal. A positioning control method, wherein a correction signal is generated from an amount, and a signal including a difference between the fine movement command signal and the correction signal is input to a fine movement mechanism. 2. A positioning control device mounted on the fine movement mechanism of a moving device comprising a coarse movement mechanism having a large movement amount but low positioning accuracy and a fine movement mechanism having a small movement amount but high positioning accuracy, A signal generator that generates a movement command signal for the positioning target; an absolute position detection unit that detects an absolute position of the positioning target with respect to a fixed position and sends a displacement signal that represents a displacement amount at this time; Relative position detection means for detecting the relative displacement amount with respect to the coarse movement mechanism, means for outputting a correction signal from the relative displacement amount generated in the positioning target, and a deviation signal representing the difference between the movement command signal and the displacement signal. A means for outputting, a means for outputting a fine movement command signal representing a difference between the deviation signal and the relative position detection means, and a means for outputting the fine movement command signal and the correction signal. And a coarse movement mechanism controlled based on a coarse movement movement command signal obtained by adding an output signal of the relative position detecting means to the deviation signal. Characteristic positioning control device.