JP2644584B2 - Variable position detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a displacement detection device, and more particularly, to a method for easily detecting the displacement of a moving member configured to change a pattern such as white or black. The present invention relates to a displacement amount detection device capable of detecting quickly and relatively accurately.

BACKGROUND OF THE INVENTION Displacement detectors for detecting the amount of movement of various moving bodies including cylinders are roughly classified into an incremental type and an absolute type. In the increment type displacement detecting device, for example, a magnetic scale is attached to a moving body in advance, and an MR element or the like is disposed to face the moving body. Then, a pulse signal obtained by subjecting the positive / cosine wave signal derived from the MR element or the like to signal processing of phase division is counted on a time axis to detect a moving amount of the moving body. On the other hand, the absolute type displacement detection device employs, for example, a differential transformer as a detection signal deriving unit, and detects a displacement amount of a moving body based on a detection signal derived according to movement of an opposed magnetic body. Is configured.

Therefore, the incremental type and the absolute type displacement amount detecting devices according to the above-described conventional techniques require a relatively complicated configuration such as mounting a magnetic scale or a differential transformer on a piston rod as a moving body. Reveal the inconvenience of doing so.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned disadvantages, and the amount of movement caused by the relative movement of the moving member with respect to the detecting means can be easily and quickly achieved with a relatively simple configuration.
Further, it is an object of the present invention to provide a displacement amount detecting device capable of detecting accurately.

[Means for Achieving the Object] In order to achieve the above object, the present invention provides a detecting device for measuring a displacement amount of a piston rod of a cylinder which is displaced linearly; A flat portion formed and provided with a pattern that changes along the displacement direction of the piston rod, and provided to face the flat portion of the piston rod, and irradiates the pattern with light, and from the pattern. A light-emitting / light-receiving means for receiving the reflected light of, and a processing circuit for processing a displacement amount detection signal representing a change in the area of the pattern caused by the displacement amount of the piston rod detected by the light-emitting / light-receiving means, The processing circuit sets a displacement amount detection signal based on a change in the area of the pattern as an address signal, and outputs data specified by the address signal. Based characterized by having a map table for deriving a predetermined output signal corresponding to a displacement amount of the piston rod to the outside.

[Example] Next, an example of a displacement amount detection device according to the present invention will be described in detail below with reference to the accompanying drawings.

In the embodiment shown in FIG. 1, a detection unit 10 for deriving a detection signal S ₁₀ detects the movement of the moving object 11, the displacement amount detection to obtain a displacement amount of the moving object 11 from the detection signal S ₁₀ Signal S
_And a signal processing system 12 that performs signal processing to derive ₁₃ .

First, the detection unit 10 includes, for example, a CCD 16 as a line sensor having 2048 pixels, and a detection signal generation member 20 attached to the moving object 11. The CCD 16 is attached to a fixed member (not shown), while the detection signal generating member 20 is movable in the mi-mo direction. A focusing rod lens array (not shown) is mounted on the light incident surface of the CCD 16. Further, a light projecting unit 18 is provided on one side of the CCD 16.
The light emitting section 18 irradiates the detection signal generating member 20 with light,
In addition, the reflected light is incident on the incident portion of the CCD 16, and is configured to emit light at a high frequency while preventing the influence of flicker. The light projecting unit 18 constitutes a detection signal deriving unit 25 together with the CCD 16. Note that an inclined black pattern 22 that changes continuously and obliquely is formed on the surface of the long detection signal generating member 20.

On the other hand, the signal processing system 12 includes a high-frequency signal generating / sending unit 24 for sending a light emission signal S ₁₁ to the light projecting unit 18, CCD driver circuit 2
Has 6. The CCD drive circuit 26 applies a drive signal S _{12 serving as} a read pulse to the CCD 16, for example, a pulse voltage of 12 V to the shift gate, and although not shown, a clock signal generation circuit, a counter circuit, a transfer pulse It has a generating circuit, and a drive circuit for converting the voltage from 5V to 12V and driving it. The signal processing system 12, the differential amplifier circuit 30 which detects the signal S ₁₀ which is read by the further the CCD16 is supplied, the sample-hold circuit 32, AGC circuit 3
4, including a binarizing circuit 36, a RAM 38 in which a map table (lookup table) is formed, and a signal distribution circuit 40.

Next, the operation of the present embodiment configured as described above will be described.

Under the biasing action of the CCD drive circuit, the detection signal generation member 20
When the movement in the direction of mo, the CCD16 derives the detection signal S _10, it is supplied to the differential amplifier circuit 30. The differential amplifier circuit 30
Although the CCD16 output of the high voltage corresponding to the detection signal S ₁₀ to the charge is derived to a reset level signal to reset the operational charges transferred for each pixel are superimposed, the differential amplifier circuit At 30 the reset level signal component (DO
Remove S). The analog signal derived after the reset level signal is removed from the differential amplifier circuit 30 in this manner is supplied to the sample and hold circuit 32. In the sample-and-hold circuit 32, the analog signal is sampled and held, and the gain is controlled by the AGC circuit 34 to be supplied to the binarization circuit 36. In the binarization circuit 36, for example, it is converted into a bipolar binarized signal and derived.

Therefore, as described above, since the black pattern 22 shifts with the movement of the detection signal generating member 20 in, for example, the direction of mo, the RAM 38 uses the binarized signal as an address as shown in FIG. The stroke (l _{1 to} l _n ) of the detection signal generating member 20 is read from the table, and this stroke signal is supplied to the signal distribution circuit 40, and then the displacement detection signal S
₁₃ is output to the output terminal 46. The displacement detection signal
S ₁₃ is supplied to the LCD or the like, or various control means (not shown) to achieve the desired purpose.

Next, an embodiment in which the above embodiment is applied to a cylinder stroke detecting device will be described.

First, the overall configuration will be described with reference to FIGS. In this case, the same components as those in the above embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG. 5 is an enlarged view of a main part.

This stroke detection device is basically composed of a cylinder 60 and a signal processing system 12.

First, the cylinder 60 will be described. The cylinder 60 includes a cylinder tube 66, a piston 68 in which a seal member is wound and slid, and a piston rod 70 connected to the piston in the cylinder tube 66. In the piston rod 70, for example, a flat portion 70a is formed, and an inclined black pattern 22 that continuously changes is formed on a flat surface of the flat portion 70a. The piston rod 70
The head 70h is attached to a device or mechanism (not shown). Further, a piston head cover 72 and a piston rod cover 74 are fitted to respective ends of the cylinder tube 66, and a piston rod 70 is axially passed through a central opening of the piston rod cover 74 with a seal member interposed therebetween. ing. In addition, CCD1
6, the detection signal deriving unit 25 including the light emitting unit 18 is the flat portion 70a
Are disposed opposite to each other. The piston head cover 72 and the piston rod cover 74 are connected to the screw members 72a, 7a.
The inside of the cylinder tube 66 is maintained in a sealed state by being tightened by 2b or the like. Here, the piston head cover 72 and the piston rod cover 74 are provided with, for example, ports 76 and 78 for sucking and discharging compressed air.

In such a configuration, the mi-mo
With the movement in the direction, the detection signal S
₁₀ is derived and supplied to the signal processing system 12. In the signal processing system 12, the piston rod 70 on the basis of the detection signal S ₁₀
Detection signal S ₁₃ indicating the amount of displacement is derived to the output terminal 46.

6 (a) to 6 (c) show modified examples of the detection signal generating member 20 and the piston rod 70. FIG. In the diagram (a), one of the two divided surfaces is formed as a black pattern 22a.
FIG. 11B is an example in which a saw-toothed black pattern 22b is formed. Further, in the diagram (c), a black pattern 22c is formed by a sine curve. In this case, it is needless to say that the same operation is performed by inverting the white pattern and the black pattern.

Variant of this type is used in consideration of the accuracy of the detection signal S ₁₀ derived and displacement detection signal generating member 20 and Pisutonrodddo 70. In this case, the corresponding map table may be provided in the RAM 38 for signal processing.

In the present embodiment, a square member is used for the detection signal generating member 20, or a round bar member is used for the piston rod 70 by flattening, but the present invention is not limited to this. For example, a member having a flat portion such as a hexagonal material can be used.

[Effects of the Invention] As described above, the displacement amount detection device of the present invention is a detection device that measures the displacement amount of a member that moves linearly, a movement unit provided with a pattern that changes along the movement direction, A light emitting unit that irradiates light to the pattern of the moving unit, a light receiving unit that receives reflected light from the pattern, and a change in the area of the pattern caused by a moving amount of the moving unit detected by the light receiving unit. And a processing circuit for processing a movement amount detection signal representing the following. The processing circuit has a map table for deriving a predetermined output to the outside using the movement amount detection signal as an address signal. As described above, with a relatively simple configuration, it is possible to quickly and accurately detect the amount of displacement at the time of relative movement of the moving means. In particular, since the map table is provided, the movement amount can be immediately obtained from the map table according to the movement amount detection signal.

[Brief description of the drawings]

FIG. 1 is an explanatory perspective view of an essential part showing an embodiment of a displacement amount detecting device according to the present invention, and FIG. 2 is a configuration diagram showing an essential part of a detecting part and a circuit block of a signal processing system shown in FIG. FIG. 3 is an explanatory view for explaining the operation of the signal processing system shown in FIG. 2, and FIG. 4 is a longitudinal section of a displacement amount detecting device for detecting displacement of a piston rod in a cylinder as another embodiment. FIG. 5 is a schematic perspective view of a main part of a piston rod and a detection unit shown in FIG. 4, and FIGS. 6A to 6C show modified examples of a detection signal generating member and a piston rod. It is a partial front view shown. 10 detection unit 11 moving object 12 signal processing system 16 CCD 18 light emitting unit 20 detection signal generating member 22, 22a to 22c black pattern 24 High frequency signal generation /
Sending means 26 CCD drive circuit 30 Differential amplifier circuit 32 Sample hold circuit 34 AGC circuit 36 Binarization circuit 38 RAM 60 Cylinder 66 Cylinder tube 68 ...... piston, 70 ...... piston rod S ₁₀ ...... detection signal, S ₁₁ ...... emission signal S ₁₃ ...... detection signal

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Nobuhiro Fujiwara 6-19-1 Inari, Soka-shi, Saitama SMC Corporation Grass Processing Plant (56) References JP-A-56-163411 (JP, A) JP-A Sho 53-100636 (JP, A) JP-A-62-110113 (JP, A) JP-A 64-10619 (JP, U) JP-A-59-52204 (JP, U)

Claims (1)

(57) [Claims] 1. A detecting device for measuring a displacement amount of a piston rod of a cylinder displaced linearly, wherein a pattern formed along a longitudinal direction of the piston rod and changing along the displacement direction of the piston rod is provided. A light emitting / receiving means provided to face the flat part of the piston rod, irradiating the pattern with light, and receiving reflected light from the pattern; and the light emitting / light receiving means. A processing circuit for processing a displacement detection signal representing a change in the area of the pattern caused by the displacement of the piston rod detected by the processing circuit, wherein the processing circuit outputs a displacement detection signal based on the change in the area of the pattern. A specific output corresponding to an amount of displacement of the piston rod based on data specified by the address signal; A displacement amount detection device having a map table for deriving a signal to the outside.