JP3339943B2 - Stage movement control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stage movement control device for controlling the movement of a stage on which a sample such as a microscope device is mounted, and more particularly to a stage movement control device for preventing damage to the stage and improving followability. About.

[0002]

2. Description of the Related Art Generally, a stage on which a sample is placed, such as a microscope, has a structure which can be moved two-dimensionally to set the sample at a desired position. The stage may be configured to move the stage by combining a ball screw rotated by a motor and a bearing mounted on the stage, or a gear rotated by the motor, and Various electric stages such as those having a structure in which a stage is moved by combining a gear and a rack that meshes with each other are used.

[0003] In any of the electric stages, various arrangements are devised in order to control the motor stage with good follow-up to an instruction from a movement instruction device such as an encoder or a trackball.

As a first specific example, there is a conventional stage movement control device as shown in FIG. This control device rotates in an arbitrary direction so as to have an arbitrary amount, and a two-phase signal A, which is determined by the rotation direction and the angle.
B, an encoder 1 for outputting B, a pulse discriminating circuit 2 for discriminating the two-phase signals A and B outputted from the encoder 1 and outputting an up pulse and a down pulse, and an end position of a stage movable range (not shown). A positive direction limit sensor 3 and a negative direction limit sensor 4 which always output a pulse passage possible signal, detect that the stage has reached any positive or negative terminal position, and output a pulse passage prohibition signal. , This sensor 3, 4
Discrimination circuit 2 when a pulse passable signal is received from the
A logic circuit 5 which outputs an up-pulse or a down-pulse sent from the sensor as a driving pulse, and prohibits the passage of an up-pulse or a down-pulse from the pulse discrimination circuit 2 when receiving a pulse passage prohibition signal from the sensors 3 and 4. , 6, a driver 7 that outputs a drive signal based on an up drive pulse or a down drive pulse output from the logic circuits 5, 6, and a motor 8 that moves a stage according to the drive signal from the driver 7. Have been.

Therefore, in the control device having such a configuration,
Normally, an up pulse or a down pulse from the pulse discriminating circuit 2 is sent to the driver 7 as a driving pulse via the logic circuits 5 and 6, and the driver 7 outputs a driving signal based on the driving pulse to output the motor 8 Drive the
Move the stage. When the stage reaches the end position of the movable range of the stage due to the movement, the limit sensor 3 or 4 detects the arrival of the end position of the stage, and sends a pulse passage prohibition signal to output the logic circuit 5 or 6.
To stop the movement of the stage.

Next, as a second specific example, there is a conventional stage movement control device as shown in FIG. This control device is provided with an encoder 11 and a pulse discriminating circuit 12 having the same functions as in FIG. 5, and a current position counter 13 for counting up pulses or down pulses from the pulse discriminating circuit 12 and outputting current position information. ing.
Reference numeral 14 denotes a CPU for executing predetermined data processing, which periodically reads out current position information from the current position counter 13 and stores the positive direction limiter position information or the negative direction limiter position information already stored in the storage devices 15 and 16. Based on the current position information and the previously read current position information, when it is determined that the current position of the stage has not yet reached the positive limiter position or the negative limiter position, control for moving the stage in the positive or negative direction The signal is output and supplied to the pulse generation circuit 17.

In this pulse generation circuit 17, the CPU 14
A drive signal is output from the driver 18 based on these drive pulses, and an up drive pulse or a down drive pulse having a frequency based on the control signal from the motor 1 is output.
9 is driven to move the stage.

[0008]

However, the control device shown in FIG. 5 has good followability with respect to an instruction pulse (a two-phase signal or an output pulse of the pulse discrimination circuit 12) from the encoder 1 as shown in FIG. However, since the stage suddenly stops at the end of the movable range of the stage, when the stage is moving toward the end at a high speed, for example, there is a problem that the stage is damaged by the sudden stop.

Next, as shown in FIG. 8, the control device shown in FIG. 6 does not exceed the maximum speed determined by the distance from the current position to the end, and stops while decelerating even when approaching the end at a high speed. So the stage is not damaged,
Conversely, since the CPU 14 performs data processing while periodically reading out the position information of the current position counter 13, there is a problem that the followability to the instruction pulse is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a stage movement control device which does not damage the stage and does not impair the followability of the stage to an instruction pulse. Aim.

[0011]

According to a first aspect of the present invention, there is provided an electronic apparatus comprising: a movable stage; and a movement instructing unit for outputting a pulse for moving the stage in a desired direction by a desired amount. A stage driving means for moving the stage by a predetermined amount in a desired direction instructed by the movement instructing means, and an end position of the stage movable range and a current position obtained from an output pulse of the movement instructing means. the distance measuring means for obtaining distance information from the current position to the end position, the output pulses of the highest frequency based on the maximum reduction ratio information and the permissible maximum speed obtained from <br/> distance measured the distance measuring means A pulse generating means for performing the frequency control on the output pulses of the movement instructing means based on the pulse frequency from the pulse generating means. And frequency limitation means for supplying to the driving means
Wherein the pulse output from the movement instruction means is
Above the maximum allowable speed or the maximum according to the maximum reduction ratio information
If the speed is equal to or higher than the speed,
Output from the pulse generating means based on the output pulse of the means.
While limiting the maximum frequency to be applied,
And output from the movement instruction means.
Pulse below the maximum allowable speed or the maximum reduction ratio
If the speed is below the maximum speed according to the report,
Move the output stage in a desired direction in a desired amount
The pulse is directly supplied to the stage driving means.
This is a stage movement control device.

[0012]

According to the present invention, when the pulse from the movement instruction means exceeds the allowable maximum speed, the invention is limited to the pulse for driving the stage. a bet can Rukoto. Further, when the stage approaches the end position of the stage movable range, the pulse for driving the stage is limited by the maximum speed according to the maximum reduction ratio information, so that the stage can be stopped properly. . Furthermore, the output pulses from the moving instruction means, permissible maximum speed or less, or if the maximum speed or less corresponding to the maximum reduction ratio information, that said pulse travels directly controls the stage as a pulse for driving the stage Thereby, the followability of the stage movement control with respect to the pulse from the movement instruction means can be improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the embodiments of the present invention,
In order to facilitate understanding of the apparatus of the present invention, characteristics of the moving speed of the stage will be described with reference to FIG. The control device according to the present invention needs to recognize the current position and the distance to the end of the movable range of the stage. This distance is recognized based on the number of drive pulses that drive the drive system of the stage movement, while using the maximum reduction ratio and the maximum allowable speed for stopping the stage and the drive unit without damaging the stage. If the speed of the instruction pulse from the encoder (up or down pulse from the two-phase signal A or B or the pulse discriminating circuit) exceeds the allowable maximum speed, the drive pulse is set to the allowable maximum speed. When the speed of the instruction pulse does not exceed the allowable maximum speed, the instruction pulse is used as a direct drive pulse to control the movement of the stage.

For example, when the stage is moved as in the moving pattern A, when the speed of the instruction pulse exceeds the maximum allowable speed, the drive pulse is limited by the maximum allowable speed.
If not, the instruction pulse becomes the drive pulse as it is. On the other hand, when the stage is moved as in the movement pattern B, when the speed of the instruction pulse from the encoder exceeds the maximum speed determined by the maximum reduction ratio, the drive pulse is limited at the maximum speed.

Therefore, the instruction pulse is a drive pulse unless it exceeds the maximum speed determined by the allowable maximum speed or the maximum reduction ratio. However, it goes without saying that the allowable maximum speed and the maximum reduction ratio differ for each device depending on the configuration of the device such as a microscope and the performance of the components.

Next, an embodiment of the stage moving control device according to the present invention will be described with reference to FIG. 1 on the premise of the characteristics of the moving speed as described above. In the figure, reference numeral 21 denotes an encoder for instructing the moving direction and the amount of a stage (not shown), and the encoder 21 determines the rotation direction and angle from the encoder 21 when the encoder rotates.
The phase signals A and B are output and supplied to the pulse discrimination circuit 22. The pulse discriminating circuit 22 discriminates the two-phase signals A and B from the encoder 21 and converts them into pulse train signals of up (UP) or down (DOWN) and supplies them to the driver 24 as drive pulses via a pulse limiter 23. I do. The driver 24 outputs a drive signal corresponding to an up drive pulse or a down drive pulse, drives the motor 25, and moves a stage (not shown) in any positive or negative direction.

Reference numeral 26 denotes a current position counter having an up / down function for counting up or down drive pulses or up / down pulses and converting the same into current position information. Circuit 2
7, 28. The subtraction circuit 27 subtracts the current position of the current position counter 26 from the forward direction limiter position indicating the forward direction end position stored in the storage device 29 in advance, and calculates forward distance information from the end to the current position. And outputs it to the pulse generation circuit 30. The subtraction circuit 28
From the negative limiter position indicating the negative end position also stored in the storage device 31 in advance, the current position counter 26
Is subtracted, negative direction distance information from the negative end to the current position is output, and sent to the pulse generation circuit 32.

The pulse generation circuits 30 and 32 output pulse train signals of the highest frequency based on the distance information from the subtraction circuits 27 and 28, the maximum reduction ratio information, and the allowable maximum speed, and supply them to the pulse limiter 23. Reference numeral 33 denotes a storage device for storing allowable maximum frequency data and other necessary data.

The pulse limiter 23 generates an up drive pulse and a down drive pulse while limiting the frequency of the up pulse or the down pulse of the pulse discrimination circuit 22 based on the pulse frequency from the pulse generation circuits 30 and 32, and generates a driver 24. And has a function as a frequency limiting means for transmitting the signal to

Next, the operation of the control device configured as described above will be described. Now, when the encoder 21 is rotated to generate two-phase signals A and B determined by the rotation direction and the angle, the pulse discrimination circuit 22 performs pulse discrimination and outputs an up or down pulse train signal. These up or down pulse train signals pass through a pulse limiter 23, and are used as driving pulses by a driver 24.
Given to. Here, the driver 24 sends a drive signal to drive the motor 25 to move the stage.

At this time, the current position counter 26 counts up or down the up drive pulse or down drive pulse, converts it into current position information, and sends it out to the subtraction circuits 27 and 28. One subtraction circuit 27 subtracts the current position of the current position counter 26 from the forward direction limiter position previously stored in the storage device 29, and obtains forward distance information from the forward end to the current position, It is sent to the pulse generation circuit 30. The other subtraction circuit 28
Subtracts the current position of the current position counter 26 from the negative direction limiter position stored in the storage device 31 to obtain negative distance information from the negative terminal to the current position,
The signal is sent to the pulse generation circuit 32.

Here, the pulse generation circuit 30 outputs a pulse train signal of the highest frequency that increases in proportion to the distance information from the subtraction circuit 27. The highest frequency of this pulse train signal is stored in the storage device 33. When the maximum allowable frequency is exceeded, a pulse train signal of the maximum frequency limited to the maximum allowable frequency is output.

Further, the operation of the pulse generation circuit 30 will be described in detail. As shown in FIG. 3, when the distance between the current position and the end of the movable range of the stage increases, the output frequency from the pulse generation circuit 30 monotonously increases. However, the slope of the increase at this time is determined by the maximum reduction ratio. Also, the monotonically increasing output frequency is limited by the frequency determined by the maximum allowable speed. Furthermore, when the stage approaches the end of the stage movable range, the drive pulse is limited by the maximum speed based on the distance information from the end of the stage movable range to the current position and the maximum reduction ratio information.

The pulse generation circuit 32 performs the same operation as the pulse generation circuit 30 and outputs a pulse train signal having the highest frequency. As described above, the pulse train signals of the highest frequency are sent from the pulse generation circuits 30 and 32 to the pulse limiter 23.

The pulse limiter 23 has a built-in flip-flop circuit set at the falling edge of the pulse train signal UP (MAX) input from the pulse generation circuits 30 and 32 as shown in FIG. Reset at the rising edge of the up pulse UP of the pulse train signal from. Then, a logical product (AND) of the output of the flip-flop circuit and the up pulse UP of the pulse train from the pulse discrimination circuit 22 is performed, and the output pulse UP (O
UT). Therefore, according to the pulse train signal UP (MAX) from the pulse generation circuit 30, the pulse limiter 2
It can be seen that the output pulse frequency of No. 3 has changed.

The same operation is performed on the pulse train signal DOWN (MAX) from the pulse generation circuit 32 to output an output pulse DOWN (OUT). Therefore, according to the configuration of the above embodiment, the encoder 2
When the output pulse from 1 exceeds the maximum allowable speed, the drive pulse for driving the stage is limited to the maximum allowable speed, and when the stage approaches the end of the movable range of the stage, the drive pulse moves. Since the stage is limited by the maximum speed based on the distance information from the end of the range to the current position and the maximum reduction ratio information, the stage can be stopped properly and the stage is not damaged. Further, when the output pulse from the encoder 21 is equal to or lower than the maximum speed based on the maximum reduction ratio information, the output pulse becomes a direct drive pulse, so that the followability to the output pulse is very good. In addition, the present invention can be implemented with various modifications without departing from the scope of the invention.

[0027]

As described above, according to the present invention, the stage is not damaged, and the followability of the stage with respect to the instruction pulse is smoothly and smoothly reduced.
It is an object of the present invention to provide a stage movement control device capable of stably moving a stage.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a stage movement control device according to the present invention.

FIG. 2 is a characteristic diagram of a stage moving speed for a plurality of moving patterns.

FIG. 3 is a diagram illustrating a relationship between a distance and an output frequency for explaining an operation of the pulse generation circuit shown in FIG. 1;

FIG. 4 is a timing chart for explaining the operation of the pulse limiter shown in FIG. 1;

FIG. 5 is a configuration diagram of a stage movement control device as one specific example of the related art.

FIG. 6 is a configuration diagram of a stage moving control device as another conventional example.

FIG. 7 is a diagram for explaining the following of the control device shown in FIG. 5 with respect to an instruction pulse from an encoder.

FIG. 8 is a diagram for explaining the responsiveness of the control device shown in FIG. 6 to an instruction pulse from an encoder.

[Explanation of symbols]

Reference Signs List 21 encoder, 22 pulse discriminating circuit, 23 pulse limiter, 24 driver, 25 stage movement motor, 26 current position counter, 27, 28 subtraction circuit, 29, 31, 33 storage device, 30 , 32 ... Pulse generation circuit.

────────────────────────────────────────────────── (5) References JP-A-5-324804 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G05D 3/00-3/20

Claims (1)

(57) [Claims] 1. A movable stage, a movement instructing means for outputting a pulse for moving the stage in a desired direction by a desired amount, and a stage drive for moving the stage in a desired direction instructed by the movement instructing means. Means for measuring distance information from the current position to the end position based on an end position of the stage movable range and a current position obtained from an output pulse of the movement instruction means; A pulse generating means for outputting a pulse of the highest frequency based on the maximum reduction ratio information and the allowable maximum speed obtained from the measurement distance of the measuring means, and an output pulse of the movement instruction means based on a pulse frequency from the pulse generating means. Yes and frequency limitation means for supplying the precursor stage driving means while applying the frequency limit
And a pulse output from said movement instructing means, wherein the maximum allowed
High speed or higher or maximum speed according to the maximum reduction ratio information
In the case of, the frequency limiting means outputs the output of the movement instruction means.
Output from the pulse generating means based on the force pulse
Driving the stage while limiting the maximum frequency
Pulse supplied to the movement instruction means and output from the movement instruction means.
Is less than the allowable maximum speed, or according to the maximum reduction ratio information.
If the speed is less than the maximum speed, the
Pulse to move the stage in a desired direction in a desired amount.
A stage moving control device, which is directly supplied to the stage driving means .