JPH02208701A - Driving fuzzy controller - Google Patents

Abstract

PURPOSE:To execute positioning of high accuracy at a high speed and with high efficiency by executing a fuzzy operation from a deviation to a target position of a moving table and a moving speed and outputting at least a moving speed to a driving mechanism and air pressure in a static pressure supporting mechanism as command values. CONSTITUTION:A fuzzy arithmetic part 25 executes a fuzzy operation of each data of a deviation DELTAe to a target position (xd) of a slider 3 and a moving speed ¦DELTAe/DELTAt¦ from a position of the slider 3 measured by a laser light interference and derives a moving distance DELTAhi' and air pressure Pi. Accordingly, in accordance with a position of the slider 3 to the target position (xd), magnitude of the moving speed, strength of the air pressure Pi and width of a time interval DELTAti for sending out a control signal of these moving speed ¦DELTAe/DELTAt¦ and air pressure Pi can be controlled by the moving distance DELTAhi. In such a way, the influence of vibration to the slider caused by air pressure becomes extremely small, and the slider 3 can be position in the target position (xd) with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a drive fuzzy control device for moving a movable table supported by static pressure to a predetermined position.

(Prior Art) FIG. 19 is a block diagram of a drive device. A guide body 2 is provided on the support base 1, and a hydrostatic air bearing guide movement table (hereinafter referred to as a slider) 3 is supported on the guide body 2. The air pressure that supports this slider 3 with static pressure is:
For example, the air pressure is controlled to an appropriate value by an air pressure control means 3a such as a solenoid valve. Further, a drive mechanism 4 consisting of a DC servo motor or a tacho generator is provided on the support base 1, and a drive rod 6 is pivotally supported by a static pressure bearing 5 of the drive mechanism 4. And this driving rod 6
One end of the slider 3 is provided on the slider 3. Therefore, the drive rod 6 is moved by the drive of the drive mechanism 4, and the slider 3 is moved in the direction of the guide body 2, that is, in the direction of arrow (A).

On the other hand, a laser oscillator 7 is provided on the support base 1, and a laser beam outputted from the laser oscillator 7 passes through an interferometer 8 and is irradiated onto a reflecting mirror 9 provided on the slider 3. The laser beam reflected by the reflecting mirror 9 enters the interferometer 8 again, and the interferometer 8 obtains interference light between the reflected laser beam and the laser beam from the laser oscillator 7. This interference light is then converted into an electrical signal through the receiver 10 and sent to the control section 11. Therefore, the main control section 11 determines the position of the slider 3 from the input electric signal, determines a movement distance control signal to the drive mechanism 4 from the deviation between this position and the movement target position, and sends it to the drive mechanism 4. Specifically, as shown in FIG. 20, the main control unit 11 sends a control signal for a moving distance Δh 1 +Δh2... at every predetermined time interval Δio+Δt1... when positioning to the target position xd. .

By the way, the air pressure (air pressure) supplied to the slider 3 is the cause of the vibration of the slider 3, for example, an amplitude of 20 to 30 ns. However, this vibration makes it impossible to position the slider 3 with high precision. In other words,
Any mechanism that does not require positioning accuracy may be used, but when positioning is performed with high accuracy on the order of nanometers, for example, the influence of vibration due to air pressure cannot be ignored. Moreover, air pressure is always supplied at a constant rate, and if the slider 3 vibrates just before reaching the target position xd, highly accurate positioning will be difficult.

(Problem WJ to be solved by the invention) When positioning the slider 3 supported by static pressure as described above, only the movement distance control signal is sent out, without taking into account the air pressure of the slider 3, The slider 3 vibrates due to air pressure, making highly accurate positioning difficult.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a drive fuzzy control device that can perform high-speed, highly efficient, and highly accurate positioning by controlling the moving speed and air pressure according to the distance to the target position.

[Structure of the Invention] (Means for Solving the Problem) The present invention provides a movable table, a static pressure support mechanism that statically supports the movable table using air pressure, and a static pressure support mechanism that moves the statically supported movable table. a drive mechanism, a position measuring means for measuring the position of the movable table, and a mechanism having in advance each membership function of at least a deviation from a target position of the movable table, a moving speed, and a position, and a moving distance of the movable table and a static pressure support mechanism. It has fuzzy set data of the air pressure at the position measured by the position measuring means, and calculates the data of the deviation from the target position of the moving table and the moving speed from the position measured by the position measuring means, performs fuzzy calculations from these data, and calculates at least the drive mechanism. This is a drive fuzzy control device that attempts to achieve the above object by including a fuzzy control means that outputs the moving speed relative to the drive speed and the air pressure in the static pressure support mechanism as command values.

(Function) By providing such means, when the movable table is moved by the drive mechanism, the position of the movable table is measured by the position measuring means.

Then, the fuzzy control means obtains data on the deviation from the target position of the moving table and the moving speed from the position measured by the position measuring means, and calculates the deviation from the target position of the moving table, the moving speed and the moving speed from these data. A fuzzy operation is performed using each membership function of the position and each fuzzy set data of the movement distance of the movement table and the air pressure, and at least the movement speed for the drive mechanism and the air pressure for the static pressure support mechanism are output as command values.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. Note that the same parts as in FIG. 19 are given the same reference numerals, and detailed explanation thereof will be omitted.

FIG. 1 is a block diagram of a drive fuzzy control device.

In the same figure, reference numeral 20 denotes a fuzzy control device, which has membership functions for the deviation from the target position of the slider 3, moving speed, and position, and at least fuzzy sets for the moving distance and air pressure of the slider 3. position measuring means or laser oscillator7. From the position of the slider 3 measured by the interferometer 81, the reflection mirror 9, and the receiver 10, data on the deviation from the target position of the slider 3 and the moving speed are obtained, and fuzzy calculations are executed from these data to calculate the data on the drive mechanism 4. It has the function of commanding the moving speed and air pressure to the air pressure control means 3a. Specifically, the configuration is as follows. That is, a main control section 21 is provided, and an input section 22, an output section 23, a storage section 24, and a fuzzy calculation section 25 are connected to this main control section 21. The input section 22 inputs an electrical signal from the receiver 10, converts it into a digital signal, and takes it in. The output section 23 converts the command into a digital signal and outputs it to the drive mechanism 4. This output section 23 is connected to the drive mechanism 4 and the air pressure control means 3a. A rule map table 26, a menno(-ship function table 27, and a fuzzy set table 28) are formed in the storage unit 2.4. Each membership function shown in FIGS. 2 to 4 is stored.

FIG. 2 shows the membership functions A-F of the deviation Δe of the slider 3 from the target position, rAJ and r
DJ is a membership function close to the target position, rB
J and rEJ are membership functions at intermediate positions from the target position, and rCJ and rFJ are membership functions at positions far from the target position. Next, Figure 3 shows each membership function of the moving speed 1Δe/Δt1 of the slider 3, where "G" is the slow membership function, rHJ is the intermediate speed membership function, and "I" is the membership function of the slow speed. It is a fast membership function. Also, Figure 4 shows the membership function of the slider position, and rJJ is slider 3.
The membership function when is located at the center of guide body 2,
“K” is a membership function when the slider 3 is near both ends of the guide body 2. Next, the fuzzy set table 28 contains fuzzy result data for the moving distance Δhi as shown in FIG. Fuzzy set data of air pressure Pi as shown in FIG. 7 is stored.

Further, the rule map table 26 stores rules for fuzzy calculations as shown in FIG. 8, and these rules have been determined empirically.

Next, the operation of the apparatus configured as described above will be explained.

The drive rod 6 is driven by the drive mechanism 4, and the slider 3 is moved, so that the slider 3 is located at a deviation Δe + 100nn from the target position xd, for example, and the moving speed 1Δe/Δt1 at this time is 0.5 μm. / se
Assume that the slider 3 reaches a position 10 mm above the guide body 2 at e. The position of the slider 3 at this time is sent to the fuzzy control device 20 through the receiver 10 as the output of the interferometer 8.

As a result, the main control unit 21 controls the slider 3 that was input this time.
Deviation Δe from the position to the target position rIlx d = +
Obtain loOnm and calculate the moving speed 1Δe/Δt-0.5 μm from the position of the slider 3 manually operated last time.
/ Find sec. Next, the main control section 21 issues an operation command to the fuzzy calculation section 25. Upon receiving this command, the fuzzy calculation section 25 first calculates each membership function. That is, the deviation Δe from the membership function shown in FIG.
+ Each membership value ω1. corresponding to 100 rv. ω
4(ω1>ω4), and from the membership function shown in Figure 3, the moving speed lΔe/Δt l −0,5p m/
The membership function ω2. ω5 (ω2〉
ω5) is calculated, and further, from the membership function shown in FIG. 4, the membership function ω6. Find ω3 (ω6>ω3). When each of the membership functions ω1 to ω6 is obtained in this way, eight combinations as shown in FIG. 9 are obtained from these membership functions ω1 to ω6. In addition,
The magnitude relationship of these membership functions ω1 to ω6 is ω5
〉ω3〉ω4〉ω1〉ω6〉ω2.

Now, calculation of the moving distance Δhi will be explained as an example. First, in the case of combination "1" shown in FIG. 9, ω1 is on the membership function rAJ, ω2 is on the membership function rGJ, and ω3 is on the membership function NJ, and these membership values ω1 to ω3 The minimum membership value among them is ω3. However,
From the rules shown in Figure 8, the membership function rAJrG
In the case of the combination J rJJ, the fuzzy set of the travel distance Δhi is rLJ, and this fuzzy set rLJ is multiplied by the membership value ω3 to form the set L shown in Figure 1O.
It becomes a. Next, in the same way as above, the combination “2” shown in FIG.
”, ω1 is on the membership function rAJ,
ω2 is on the membership function rGJ, ω6 is on the membership function rKJ, and these membership values ω1, σ2 . The minimum membership value among ω6 is ω1
It becomes. However, according to the rules shown in FIG. 8, in the case of the combination of membership functions rAJ rGJ rKJ, the fuzzy set of the moving distance Δhi is rLJ, and this fuzzy set rLJ is multiplied by the membership value ω1 as shown in FIG. This becomes a set Lb. Similarly, sets Lc and Ld of each membership value combination "3" to "8" are shown below.

Ma, Le, Mb, and Mc are required. Next, the fuzzy calculation unit 25 calculates each set La, Lb, and
...Ma... is synthesized to obtain a composite function Y as shown in FIG.
Find g. However, the moving distance Δh from this center of gravity Yg
i゛ is required.

Next, when calculating the air pressure Pi, the membership function is rAJ from the combination "1" shown in FIG. 9 in the same way as above.
rGJ rJJ, and the minimum membership value among these membership values ω1 to ω3 is ω3. However, according to the rules shown in FIG. 8, the fuzzy set of the air pressure Pi is rVJ, and this fuzzy set rVJ is multiplied by the membership value ω3. Similarly, in the case of combination "2" shown in FIG. 9, the membership functions are rAJ rGJ rKJ, and the minimum membership value is ω1. However, from the rules shown in Figure 8, the fuzzy set of air pressure Pi is r
VJ, and this fuzzy set rVJ is multiplied by the membership value ω1. Thereafter, fuzzy sets for each membership value combination "3" to "8" are found in the same way. Then, the fuzzy calculation unit 25 synthesizes the fuzzy sets obtained as described above to obtain a composite function, and the air pressure pt is determined from the center of gravity Yg of this composite function.

Note that the time interval Δti is also found in the same manner.

Therefore, the fuzzy calculation unit 25 sequentially calculates Δhi.

Pi and Δ11 are determined, and the fuzzy control device 2
0 outputs a moving distance control signal sh of Δh1 to the drive mechanism 4, and also sends an air pressure control signal SP of Pl to the air pressure control means 3a.

In this way, in the above embodiment, a fuzzy calculation is performed from each data of the deviation Δe from the position of the slider 3 measured by laser beam interference to the target position xd of the slider 3 and the moving speed 1Δe/Δt1. Travel distance Δ
Since hi' and air Pi are calculated, the moving distance Δ is determined according to the position of the slider 3 with respect to the target position xd.
By hi, the magnitude of the moving speed, the strength of the air pressure Pi, and the width of the time interval Δti for transmitting the moving speed 1Δe/Δt1 and the control signal for the air pressure Pi can be controlled. In other words, when the slider 3 approaches the target position xd, the moving distance Δhi is reduced, and conversely, when the slider 3 is far from the target position xd, the moving distance Δhi is increased, and when the slider 3 approaches the target position xd, the speed Δe/Δt1 is reduced. , conversely, if the object is far from the target position xd, control can be performed using ambiguous expressions such as increasing the speed 1Δe/Δt1. This allows for flexible and highly efficient control similar to human thinking. As a result, the slider 3 can be positioned at the target position xd with high precision by minimizing the influence of vibration on the slider 3 due to air pressure.

Note that the present invention is not limited to the above-mentioned embodiment, and may be modified without departing from the spirit thereof.

[Effects of the Invention] As detailed above, according to the present invention, the drive fuzzy control enables high-speed, highly efficient, and highly accurate positioning by controlling the moving speed and air pressure according to the distance to the target position. equipment can be provided.

[Brief explanation of the drawing]

1 to 18 are diagrams for explaining one embodiment of the drive fuzzy control device according to the present invention, in which FIG. 1 is a configuration diagram, and FIGS. 2 to 4 show each membership function. Figures 5 to 7 are diagrams showing each fuzzy set, Figure 8 is a diagram showing a rule map, Figure 9 is a diagram showing combinations of membership values, and Figures 10 to 17 are diagrams showing movement. Diagram showing the fuzzy set found when calculating distance, 1st
Figure 8 is a diagram showing the operation of determining the moving distance from the center of gravity, Figure 19
The figure is a block diagram of a conventional drive control device, and FIG. 20 is a diagram for explaining the operation of the device. DESCRIPTION OF SYMBOLS 1... Support stand, 2... Guide body, 3... Slider 4... Drive mechanism, 5... Static pressure bearing, 6... Drive rod, 7... Laser oscillator, 8... ...Interferometer, 9...
- Reflection mirror 10...Regiver, 21...Main control section, 22...Input section, 23...Output section, 24...Storage section, 25...Fuzzy operation section, 26... Rule map table, 27...Membership function table, 28...Fuzzy set table. Applicant's Representative Patent Attorney Takehiko Suzue Figure 2 Figure 3 Figure 5 Figure 6 Figure Figure 9 Figure 10 Figure 12 vJ14 Figure 16 Figure vP, Figure 11 Figure 13 Figure 1U5 Figure 17 Figure 18 figure

Claims (1)

[Claims] a movable table, a static pressure support mechanism that statically supports the movable table using air pressure, a drive mechanism that moves the statically supported movable table, a position measuring means that measures the position of the movable table; It has at least membership functions of a deviation from a target position of the moving table, a moving speed, and a position, and fuzzy set data of a moving distance of the moving table and an air pressure in the static pressure support mechanism, and Data on the deviation from the target position of the moving table and the moving speed from the position measured by the measuring means are obtained, and fuzzy calculations are performed from these data to determine at least the moving speed with respect to the drive mechanism and the moving speed with respect to the static pressure support mechanism. 1. A drive fuzzy control device comprising: fuzzy control means for outputting air pressure as a command value.