JPH0431702A - Two-dimensional relative-position detection - Google Patents

Abstract

PURPOSE:To perform detection at a high speed by separately providing target flags in the patterns which are divided into two-dimensional directions (x) and (y), separately providing reflecting type photoelectric sensors for detecting the target flag in the direction (x) and the reflecting type photoelectric sensor for detecting the target flag in the direction (y), and independently detecting the relative positions in the (x) direction and the direction (y) at the same time. CONSTITUTION:An (x)-direction detecting reflection photoelectric sensor 4x and a (y)-direction detecting photoelectric sensor 4y are provided at both ends of a medium holding part 2a of a medium-operating hand part 2a which is a movable part. Meanwhile, a containing shelf 6 is provided on the fixed side. A hand mechanism 2 is positioned at both sides of the containing shelf 6. At this time, an (x)-direction target flag 5x having the specified width in the direction (x) is provided at the position corresponding to the reflection-type photoelectric sensor on the hand mechanism 2. A (y)-direction target flag 5y having the specified width in the direction (y) is provided at the position corresponding to the sensor 4y. As a result, the output of the sensor 4x is changed by the presence or absence of the flag 5x. With respect to the sensor 4y, the direction (y) is scanned by the same way.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is a non-contact method for positioning a hand mechanism for media manipulation on an arbitrary storage shelf in an automatic media exchange device for a collective mass storage device, etc. The present invention relates to a dimensional relative position detection method, and particularly to a two-dimensional relative position detection method that allows positioning to be performed with high precision and high speed.

[Prior Art] FIG. 6 shows an example of an automatic medium exchange device in a mass storage device. In general, automatic media switching devices include optical disks,
A medium storage 1 that stores recording medium cartridges 7 such as magnetic tapes, a medium operation hand mechanism 2 that takes out/stores the recording medium cartridges 7 in any storage shelf in the medium storage 1, and a medium operation hand mechanism 2 It is comprised of a hand mechanism transport device 3 that freely transports the hand mechanism 2 within the medium storage 1.

The medium handling hand mechanism 2 is positioned with respect to a specific storage fence using the encoder of the drive motor of the hand mechanism transport device 3 and the linear scale on the drive track.

In this case, since the position detection sensor and the media manipulation/) hand mechanism 2 and the storage shelf that actually position the media are placed apart from each other, in addition to the servo errors in the system, the assembly accuracy of the mechanism is affected by the positioning accuracy. greatly affects.

In particular, positioning may be affected by deformation of the frame over time due to unbalanced loads on the mechanism due to the weight of the recording media cartridge/strip 7 stored in the storage shelf, processing distortion of the storage shelf, non-flatness of the equipment installation floor, etc. Accuracy also decreases significantly over time.

For this purpose, not only high precision is required in the assembly of the mechanism, but also the rigidity of the mechanism is increased by using a honeycomb frame, etc.
It is necessary to prevent accuracy from deteriorating due to deformation of the mechanism. Therefore,
Frame costs are rising.

Therefore, in order to reduce the assembly accuracy of the mechanism and to position the media manipulation hand mechanism 2 to the target storage shelf with high precision, a target flag for positioning is provided for each storage shelf, and the media manipulation hand mechanism 2 is provided with a target flag for positioning for each storage shelf. A method is adopted in which the medium operating hand mechanism 2 is directly positioned on the target storage shelf by detecting the target flag with a position sensor provided in the storage shelf.

In this case, since the relative position between the medium handling hand mechanism 2 and the storage shelf is directly detected, positioning can be performed without being affected by the assembly accuracy of the frame or the transport device.

By the way, there is a method of detecting a relative position by image processing using a camera as the above-mentioned position sensor, but the processing is complicated and is not suitable for speeding up, and also leads to an increase in price.

On the other hand, there is a method using a transmission type optical sensor.

By using this in combination with the encoder of the motor for driving the transport device, it becomes possible to detect the position at low cost and with high precision.

However, in the case of a transmission type optical sensor, it is necessary to arrange the sensors on both sides of the target flag.

Therefore, when the storage shelves are arranged two-dimensionally and the medium manipulation hand mechanism 2 moves in two directions within the XY plane relative to the storage shelves, this transmission type optical sensor may be difficult to arrange. Become.

On the other hand, if a reflective photoelectric sensor is used, this sensor need only be placed on one side of the target flag, so there is no structural restriction even when the medium manipulation hand mechanism 2 moves two-dimensionally.

However, in this reflective photoelectric sensor, the sensor characteristics change depending on the distance from the target flag to be detected (distance between the media handling/% storage mechanism and the storage shelf), and the position detection accuracy is unstable. Another problem is that the position detection resolution is inferior to that of a transmissive optical sensor.

Therefore, we proposed a method that reduces the effects of detection distance and reflectance by determining the center of the target flag from both end positions of the target flag while using this reflective photoelectric sensor, making it possible to detect relative positions with high precision. The present inventor did this (Japanese Patent Application No. 63-244548).

[Problem to be solved by the invention] However, in this case, in order to find the center of the target flag in two directions, it is necessary to detect the four sides of the target flag, and to do so, the four sides must be sequentially scanned with a sensor. Therefore, there was a problem in that it was difficult to detect the center position at high speed.

The present invention improves the above-mentioned drawbacks and provides a method for detecting the two-dimensional X-direction position and the X-direction position individually, thereby detecting the two-dimensional relative position not only with high accuracy but also with high speed. be.

[Means for Solving the Problems] The present invention provides target flags for two-dimensional X-direction and X-direction, and the reflective photoelectric sensor is used for detecting the X-direction target flag and for X-direction. A separate device was provided for detecting the target flag, and means was taken to independently and simultaneously detect the relative positions in the X direction and the X direction.

[Operation] In the present invention, the two-dimensional X-direction position and the X-direction position are detected independently and simultaneously, and the detection time is shortened compared to the case where the X-direction and the X-direction are sequentially detected.

[Example] Hereinafter, an example of the present invention will be described. First, the principle of detecting the flag center position from both edges of the flag will be explained. FIG. 7(a) shows the operating characteristics of the reflective photoelectric sensor, and FIG. 7(b) shows the relationship between the reflective photoelectric sensor and the flag.

The shaded range in FIG. 7(a) is the ON operation region, and within this range, the reflective photoelectric sensor 4 detects the target flag 5 and its output becomes ON. When positioning is performed at the boundary of this ON operation region, the rising/falling position of the output signal of the sensor 4 (
Since the ON and OFF positions change, the detection distance 2 affects the position detection accuracy. For example, when the detection distance is 21, the sensor 4 detects the position of the X machine, but when the detection distance is z2, it detects the position of x2.

Therefore, the positions of the boundaries at both ends of the target flag 5 (for example, detection positions X□, XS at a position of detection distance 2□) are detected, and the center position X of the target flag 5 is determined from that position. If , the relative position can be detected with high precision without being affected by the detection distance 2.

Based on this principle, when detecting the relative position in two directions of xly, as shown in FIG.
x3 is found, and then y and y3 are found in the X direction. That is, by sequentially scanning the four edges of flag 5 with a sensor, these
□ Find y3, then set X as the center position of X-work and x3.

and y as the center position of yl and y3. will be asked for.

Therefore, compared to the case where the position is detected in only one direction, either X or Y, the time it takes for the sensor 4 to scan the edge of the flag 5 is longer, and the time required to detect the center position is longer, which is the problem mentioned above. occurs.

Therefore, if dedicated flags and sensors are used for each of the X and X directions and the center position detection in both directions is performed simultaneously, the time required to detect the center position can be reduced by half.

Examples of the two-dimensional relative position detection method of the present invention will be described below. FIG. 1 shows the first embodiment. Also, the second
The figure shows an example of target flag placement on a storage shelf.

In this embodiment, the medium operating hand mechanism 2, which is the movable part side,
A reflective photoelectric sensor 4x for detecting the X direction and a reflective photoelectric sensor 4y for detecting the Y direction are provided at each end of the medium holding portion 2a. On the other hand, on both sides of the storage shelf 6, which is the fixed side, when the medium manipulation hand mechanism 2 is positioned, there is a position corresponding to the reflective photoelectric sensor on the hand mechanism 2, that is, X direction detection. A target flag 5x for the X direction has a constant width in the X direction at a position corresponding to the reflective photoelectric sensor 4X for detection, and a target flag 5x for the X direction has a constant width in the X direction at a position corresponding to the reflective photoelectric sensor 4y for y direction detection. A target flag 5y for the X direction is provided.

As a result, when the X-direction reflective photoelectric sensor 4x scans the corresponding X-direction target flag 5x in the X direction, the output of the X-direction reflective photoelectric sensor 4x changes depending on the presence or absence of the X-direction target flag 5x. As a result, an output signal f (X) as shown in FIG. 3 is obtained.

Similarly, by scanning the y-direction reflective photoelectric sensor 4y in the X direction, an output signal f (y) similar to f (X) in FIG. 3 can be obtained.

At this time, the target flags 5x placed on both sides of the storage shelf,
5y has a different shape. That is, the X-direction target flag 5x has a constant width in the X-direction and a sufficient length in the X-direction. Similarly, the X-direction target flag 5y has a constant width in the X-direction and a sufficient length in the X-direction.

Here, the length of the X-direction target flag 5X in the X direction means that when the y-direction reflective photoelectric sensor 4y scans the X-direction target flag 5y in the X direction, the X-direction reflective photoelectric sensor 4X This refers to the length that does not deviate from the target flag 5X for the X direction. Similarly, the length of the X-direction target flag 5y in the X direction means that when the X-direction reflective photoelectric sensor 4x scans the X-direction target flag 5x in the X direction, the y-direction reflective photoelectric sensor 4y The length is enough to keep the direction target flag 5y from falling off.

Therefore, even if scanning in the X direction and scanning in the X direction are performed simultaneously, the output signals f (X) and f (y) shown in FIG. 3 can be obtained independently.

Therefore, using a rotary encoder attached to the output shaft of the X-direction drive motor of the hand mechanism transport device 3,
The rising position (ON position) X□ and the falling position (OFF position) x2 of the output signal of the X-direction reflective photoelectric sensor 4x are determined. Simultaneously and independently, the rising position (ON position) y and the falling position (OFF position) y2 of the output signal of the reflective photoelectric sensor 4y for the y direction are determined, and from these, the center of the target flag 5 in the X direction is determined. Position X. and the center position y in the X direction. is obtained from (X-work+x2)/2 and (y-work+ya)/2.

At this time, the apparent widths (X + xz) and (y + y2) of the target flags 5x and 5y seen from the reflective photoelectric sensors 4x and 4y are the distance between the sensor 4 and the target flag 5, that is, the detection distance. However, as explained in FIG. 7, the center position remains constant without being affected by the detection distance.

According to the above method, two flags of different shapes are used for one storage position, but as shown in FIG. By arranging the target flag 5y, the flag can be shared with the storage shelf in the adjacent row, and the number of flags will not be doubled compared to the conventional one.

In addition, if the flag is shared between adjacent storage shelves,
The arrangement of the target flags is reversed between the storage shelves in the column and the storage shelves in the i+1th column. The reflective photoelectric sensors 4x and 4y are physically the same, and depending on the shape of the corresponding flag,
It functions for the X direction and for the X direction.

Therefore, the storage shelf in the i-th column in FIG.
In one row of storage shelves, the positions of the X-direction target flag and the X-direction target flag are reversed, so the roles of the sensors are also swapped. That is, the sensor that functions for the X direction in the i-th column functions for the X direction in the i+1th column, and similarly, the sensor that functions for the X direction in the i-th column functions for the X direction in the i+1th column. Further, in the i+2th column, it is the same as in the case of the i-th column.

From the above, as long as it is known which row the target storage shelf is, it is possible to simultaneously detect the relative position in the X direction and the relative position in the X direction, and to detect the center position at high speed.

FIG. 4 shows a second embodiment of the two-dimensional relative position detection method of the present invention. In this embodiment, as shown in the figure, a first sensor 4x and a second sensor 4x2 for detecting the X direction are arranged at regular intervals in the X direction on the hand mechanism 2 for operating the medium, which is the movable part. However, an X-direction target flag 5x having a constant width in the X-direction is provided on the storage shelf 6 on the fixed part side, as in the first embodiment. Similarly, first sensors 4V for X-direction detection are spaced at regular intervals in the X-direction.

and a second sensor 4y2, and an X-direction target flag 5y having a constant width in the X-direction is provided on the storage shelf 6 on the fixed part side, as in the first embodiment.

FIG. 5 is a diagram showing the relationship between the center position of the two X-direction sensors 4x and 4x2 and the output signal of each sensor with respect to the X-direction target flag 5x. Two sensors 4 for the X direction
x-work, 4x2 are ±D/in the X direction from the center position, respectively.
2, the phases of the two output signals are f (x-D/2) and f (x+D/2), respectively.
2).

When the first sensor 4x□ detects the edge of the target flag (the edge at which the output signal turns ON), the position of the drive motor of the hand mechanism transport device 3 on the rotary encoder is Assuming that the position when the edge of the target flag (the edge at which the output signal turns OFF) is detected by the sensor 4x2 is X2, the center position of the target flag in the X direction is equal to the detection distance Z, as in the first embodiment. Regardless, (X
It is calculated as: +x2)/2.

Similarly, regarding the X direction, the two sensors 4y and 4y2 for the X direction are moved from the center position to the
/2 shifted, and by the same means as in the X direction,
Y direction center position y. Detect.

In this second embodiment, the direction of the position error relative to the target position can be known from the two sensor outputs. That is, as shown in FIG. 5, of the two sensors, only the first sensor 4x1 (or 4y) is set to the target flag 5x(
or 5y), it means that the position has shifted in the (+) direction with respect to the target position, and by scanning in the (-) direction, the positions X□ and X2 can be detected. Conversely,
If only the second sensor 4x2 (or 4y2) detects the target flag 5x (or 5y), it means that the position has shifted in the (-) direction, so correct the position in the (+) direction. do it.

By adopting this method, it is possible to know the direction of the position error, and at the same time, the scanning distance is shortened, so that the time required for relative positioning can be further shortened compared to the first embodiment.

[Effects of the Invention] According to the relative position detection method of the present invention, the media manipulation hand mechanism and the target flag storage shelf can be connected to each other with high precision without being affected by changes in the distance between the media manipulation hand mechanism and the storage shelf. In addition to being able to detect the relative position of , there is an advantage that the detection can be performed at high speed.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a two-dimensional relative position detection method according to the first embodiment of the present invention, FIG. 2 is an explanatory diagram of the arrangement of target flags in the same embodiment, and FIG. 3 is a diagram depicting the medium for target flags in the same embodiment. A diagram showing the relationship between the position of the operating hand mechanism and the sensor output signal, FIG. 4 is an explanatory diagram of the sensor arrangement in the two-dimensional relative position detection method of the second embodiment of the invention, and FIG. 5 is a diagram showing the relationship between the position of the operating hand mechanism and the sensor output signal. A diagram showing the relationship between the X (or y) direction position of the medium manipulation hand mechanism with respect to the target flag and the output signals of the two X (or y) direction detection sensors. FIG. 7 is a diagram showing an example of the detection characteristics of a reflective photoelectric sensor, and FIG. 8 is an explanatory diagram of position detection for two-dimensional relative position detection. 1... Media storage, 2... Hand mechanism for media operation,
3...Hand mechanism transport device, 4x, 4x, 4x2.
4y14y, 4y2...reflective photoelectric sensor, 5x,
5y...Target flag, 6...Storage shelf, 7...Recording medium cartridge.

Claims (1)

[Claims] (1) A storage for storing recording medium cartridges such as optical disks and magnetic tapes, a hand mechanism for operating the medium that takes out and stores the cartridges in any storage shelf in the storage, and a hand mechanism for operating the medium. In the automatic medium exchange device, which is equipped with a hand mechanism conveyance device for transferring the media within a storage, a target flag is provided corresponding to the storage shelf, and a reflective photoelectric sensor provided in the hand mechanism for handling the medium is used to detect a specific target. A two-dimensional relative position detection method for detecting a target flag and positioning the medium manipulation hand mechanism on a target storage shelf, the target flag being provided separately for two-dimensional x-direction and y-direction, and , wherein the reflective photoelectric sensor is provided separately for detecting a target flag for the x direction and for detecting a target flag for the y direction, and detects relative positions in the x direction and the y direction independently and simultaneously. Relative position detection method.