JP2012127865A - Optical displacement sensor and method for detecting step therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical displacement sensor which detects a period to be a step candidate and reduces an influence of a variation in a displacement amount due to vibration of a conveying device such as a belt conveyor and a variation in a displacement amount in the time direction, thereby further accurately detecting a step, and to provide a method for detecting the step in the optical displacement sensor.SOLUTION: An optical displacement sensor calculates the displacement amount of a detecting object based on an output of a receiver, and performs a sampling at a prescribed timing. The optical displacement sensor calculates a difference value between the displacement amount sampled previously and the displacement amount sampled this time and determines a step period and a non-step period based on the calculated difference value. Then, the optical displacement sensor calculates an integrated value of the difference value in a period determined to be the step period, and compares a maximum value of the integrated value calculated for every period determined to be the step period with a first threshold to determine whether it is the step or not.

Description

  The present invention relates to an optical displacement sensor and a step detection method in the optical displacement sensor. In particular, an optical displacement sensor that detects a step on the surface of the detection object based on the output of a light receiver that receives the reflected light reflected on the surface of the detection object, and the optical displacement sensor. The present invention relates to a step detection method.

  An optical displacement sensor is often used in addition to a photoelectric sensor as a sensor that irradiates a detection target with light to detect the presence / absence of the detection target, a desired shape of the detection target, and the like. The optical displacement sensor calculates the displacement amount of the detection object based on the reflected light reflected from the detection object surface of the projection light irradiated to the detection object, and the calculated displacement amount is equal to or greater than a predetermined threshold value. Alternatively, it is determined whether it is between a predetermined upper limit threshold and a lower limit threshold, and the presence / absence of the detection target, a desired shape of the detection target, and the like are detected based on the determination result.

  In general, detection of a detection target using a sensor is performed by relatively moving at least one of the sensor and the detection target. For example, the sensor is fixed to an apparatus or equipment, and the detection target is transferred to a belt conveyor. It is performed by moving it with a transfer device such as. The displacement sensor detects a relative displacement amount between the displacement sensor and the detection object. For example, when the amount of fluctuation due to vibration of a conveyor such as a belt conveyor is relatively large when the amount of displacement due to an object to be detected, such as a step of a paper sheet or a step of a metal plate, is used as a reference, It is difficult to distinguish by a displacement sensor whether it is a variation due to a step, a step of a metal plate, or a variation due to a vibration of a transport device such as a belt conveyor.

  Therefore, in Patent Document 1, the detection signal of the displacement sensor is differentiated to detect a step so as to distinguish between a steep displacement variation due to the presence of a step and a relatively moderate displacement variation due to vibration. is doing. Further, in Patent Document 2, the step is detected by utilizing the fact that the characteristics of the received light waveform transition at a stretch between the upper step and the lower step. Furthermore, in patent document 3, the peak and trough of the waveform of the detection signal of a displacement sensor are discriminate | determined, and the number of detection objects is counted.

Japanese Patent Application Laid-Open No. 07-271945 JP 2008-145159 A JP 2005-108052 A

  However, the differential value of the displacement greatly depends on the conveyance speed of the detection object. For example, when it is desired to detect a step of 1 mm, the unit of the differential value of displacement is “mm / second” or “mm / sampling”. Therefore, in Patent Document 1, the threshold value for determining the level difference includes units such as time and speed. Therefore, the setting of the threshold value is not intuitive for the setter and is difficult to set. It was. Further, when the conveyance speed is changed, the differential value is changed even if the object is the same detection target, and it is difficult to set an appropriate threshold value. In particular, when the detection operation includes digital processing, the differential value may be halved depending on the sampling timing, making it difficult to detect stably. Furthermore, in order to calculate the differential value of the displacement, it is necessary to set a cutoff frequency, a sampling frequency, etc. separately from the threshold as parameters that serve as a reference for fluctuations, and setting such frequencies is also intuitive for the setter. It is not easy and not easy.

  In Patent Document 2, the step is detected by utilizing the fact that the received light waveforms at the upper and lower steps of the step transition at a stroke. However, when the step is very small, the received light waveform at the upper and lower steps is separated. May be difficult. In addition, when the vertical side surface of the step is inclined slightly upward, the amount of displacement gradually increases, so that the received light waveform does not transition all at once, making it difficult to detect the step.

  Furthermore, in Patent Document 3, it is difficult to detect a step unless the peaks and valleys of the waveform indicating the displacement are clear, and the characteristic features of the differentiation are lost in the first place. As with displacement sensors that do not use the function, for example, the amount of fluctuation due to vibration of a conveyor device such as a belt conveyor when the amount of displacement due to a detection object such as a paper sheet level difference or a metal plate level difference is a reference. When it is large, it is difficult to distinguish by a displacement sensor whether it is a variation due to a step of a paper sheet, a step of a metal plate, or a variation due to vibration of a conveying device such as a belt conveyor.

  The present invention has been made in view of the above circumstances, and can detect a step more reliably by reducing the influence of fluctuations in displacement due to vibrations of a conveying device such as a belt conveyor and fluctuations in displacement in the time direction. It is an object of the present invention to provide an optical displacement sensor and a step detection method in the optical displacement sensor.

  In order to achieve the above object, an optical displacement sensor according to a first aspect of the present invention irradiates a detection object with projection light and receives reflected light reflected by the detection object using a light receiver. In the optical displacement sensor for acquiring the displacement amount of the sensor, a displacement amount calculating means for calculating the displacement amount of the detection object based on the received light signal of the light receiver sampled and acquired at a predetermined timing, and the displacement sampled last time A difference value calculating means for calculating a difference value between the amount and the displacement amount sampled this time, a determining means for determining a step period and a non-step period based on the calculated difference value, and a period determined as the step period A difference integrating means for calculating an integrated value of difference values, and a step for determining whether or not the difference is a step by comparing the maximum value of the integrated value calculated for each period determined as the step period and a first threshold value. Discrimination Characterized in that it comprises a stage, and an output means for outputting a determination signal regarding whether a level difference.

  The optical displacement sensor according to a second aspect of the invention is characterized in that, in the first aspect of the invention, the optical displacement sensor further comprises display means for displaying an integrated value of the difference values calculated in the period determined as the step period.

  The optical displacement sensor according to a third aspect of the invention is characterized in that, in the first or second aspect of the invention, the optical displacement sensor further comprises reset means for resetting an integrated value of difference values calculated in the period determined as the step period to zero. To do.

  Next, in order to achieve the above object, an optical displacement sensor according to a fourth aspect of the present invention irradiates a detection target with projection light and receives reflected light reflected by the detection target using a light receiver. In an optical displacement sensor for acquiring a displacement amount of a detection object, a displacement amount calculating means for calculating a displacement amount of the detection object based on a light reception signal of the light receiver obtained by sampling at a predetermined timing, and a previous time A difference value calculating means for calculating a difference value between the sampled displacement amount and the currently sampled displacement amount; a determining means for determining a step period and a non-step period based on the calculated difference value; and the step period. A reference displacement specifying means for specifying a reference displacement in a given period, a step determining means for comparing the difference value between the current displacement and the reference displacement with a first threshold to determine whether or not it is a step, and a step Is there And an outputting means for outputting a determination signal regarding.

  An optical displacement sensor according to a fifth aspect of the invention is characterized in that, in the fourth aspect of the invention, the optical displacement sensor further comprises reset means for resetting the reference displacement to the current displacement in a period determined as the step period.

  The optical displacement sensor according to a sixth aspect of the present invention is the optical displacement sensor according to any one of the first to fifth aspects, wherein the determination unit determines whether or not the difference value is equal to or greater than a second threshold value at each timing. The period determined to be equal to or greater than the second threshold is determined to be a step period.

  An optical displacement sensor according to a seventh aspect of the present invention is the optical displacement sensor according to any one of the first to fifth aspects, wherein the determination unit determines whether or not the difference value is equal to or greater than a second threshold value at each timing. Even if it is a period determined to be smaller than the second threshold, if any difference value is determined to be equal to or greater than the second threshold within the immediately preceding predetermined period, it is determined that it is a step period. It is made to do so.

  An optical displacement sensor according to an eighth aspect of the present invention is the optical displacement sensor according to any one of the first to seventh aspects, further comprising stop instruction receiving means for receiving a stop instruction for stopping outputting the displacement amount. To do.

  An optical displacement sensor according to a ninth aspect of the invention is the optical displacement sensor according to any one of the first to eighth aspects, wherein the output means outputs the determination signal as a one-shot pulse signal having a certain time width. It is characterized by that.

  Next, in order to achieve the above object, an optical displacement sensor according to a tenth aspect of the invention irradiates a detection target with projection light and receives reflected light reflected by the detection target using a light receiver. In an optical displacement sensor that acquires a displacement amount of a detection object, a displacement amount calculation unit that calculates a displacement amount of the detection object based on a light reception signal of the light receiver that is sampled and acquired at a predetermined timing; and Discriminating means for discriminating a step period and a non-step period based on a variation in displacement amount, a first representative value representing one of an upper stage or a lower stage of a step based on a displacement amount acquired during the step period, and immediately before the step period Step calculating means for calculating a step representative value based on the second representative value representing the other of the upper step or the lower step of the step based on the displacement obtained during the non-step period, and calculating for each period determined as the step period Step difference value and number And the step determination means for comparing the threshold value to determine whether the difference in level, and an outputting means for outputting a determination signal regarding whether a level difference.

  Next, in order to achieve the above object, the step detection method according to the eleventh aspect of the present invention is to detect a detection object by irradiating the detection object with projection light and receiving the reflected light reflected by the detection object using a light receiver. In a step detection method in an optical displacement sensor for acquiring a displacement amount of an object, a step of calculating a displacement amount of the detection object based on a light reception signal of the light receiver obtained by sampling at a predetermined timing, and calculation Determining the step period and the non-step period based on the difference value of the displacement amount, calculating the integrated value of the difference values in the period determined as the step period, and the period determined as the step period A step of comparing the maximum value of the integrated value calculated for each and a first threshold value to determine whether or not a step is present, and a step of outputting a determination signal regarding whether or not it is a step. And

  Next, in order to achieve the above object, the step detection method according to the twelfth aspect of the invention irradiates a detection target with projection light, and receives and detects the reflected light reflected by the detection target using a light receiver. In a step detection method in an optical displacement sensor for acquiring a displacement amount of an object, a step of calculating a displacement amount of the detection object based on a light reception signal of the light receiver obtained by sampling at a predetermined timing, and calculation A step of determining a step period and a non-step period based on a difference value of the displacement amount, a step of identifying a reference displacement in the period determined to be the step period, and a difference value between the current displacement and the reference displacement And a first threshold value to determine whether or not it is a step, and a step of outputting a determination signal regarding whether or not it is a step.

  In the first invention and the eleventh invention, the displacement amount of the detection target is calculated based on the received light signal of the light receiver sampled and acquired at a predetermined timing, and becomes a step candidate based on the difference value of the calculated displacement amount. A step period and a non-step period that does not become a step period are discriminated. The integrated value of the difference value in the period determined as the step period is calculated, and the maximum value calculated for each period determined as the step period is compared with the first threshold value to determine whether or not it is a step. Discriminate and output a discrimination signal regarding whether or not it is a step. By determining that the displacement period is a step period from the time when the displacement amount fluctuates relatively large, and determining that the displacement amount during the step period is equal to or greater than the first threshold, Even if the fluctuation per sampling is relatively gradual, it is possible to reliably detect the step by once determining whether or not it is a step candidate, and further using the step determination threshold (first threshold). By discriminating, it is possible to eliminate fluctuations other than steps. Therefore, even when the amount of displacement due to the level difference is relatively slow per time or per sampling, the level difference can be reliably detected.

  In the second invention, by displaying the integrated value of the difference values calculated in the period determined as the step period, it becomes easy to visually recognize the size of the step that has been difficult to read in the past.

  In the third aspect of the invention, it is possible to reliably detect the height of the step at a desired position by resetting the integrated value of the difference values calculated during the period determined as the step period to zero.

  In the fourth invention and the twelfth invention, the displacement amount of the detection target is calculated based on the light reception signal of the light receiver sampled and acquired at a predetermined timing, and becomes a step candidate based on the difference value of the calculated displacement amount. A step period and a non-step period that does not become a step period are discriminated. The reference displacement in the period determined as the step period is specified, and the difference value between the current displacement and the reference displacement is compared with the first threshold value to determine whether it is a step or not. A discrimination signal is output. By determining that the displacement period is a step period from the time when the displacement amount fluctuates relatively large, and determining that the displacement amount during the step period is equal to or greater than the first threshold, Even if the fluctuation per sampling is relatively gradual, it is possible to reliably detect the step by once determining whether or not it is a step candidate, and to calculate the difference value between the current displacement and the reference displacement. By determining the step compared with the step determination threshold (first threshold), it is possible to eliminate fluctuations due to other than the step. Therefore, it is possible to reliably detect the step even when the displacement per hour or the fluctuation per sampling due to the step is relatively gradual.

  In the fifth aspect, the height of the step at a desired position can be reliably detected by resetting the reference displacement to the current displacement in the period determined as the step period.

  In the sixth aspect of the invention, it is determined whether or not the difference value is greater than or equal to the second threshold value for each timing, and the period determined to be greater than or equal to the second threshold value is determined as the step period, whereby the amount of displacement By appropriately setting a threshold value for determining whether the fluctuation is due to the vibration of the transport device or the step, it is possible to reliably detect even a small step.

  In the seventh invention, it is determined whether the difference value is greater than or equal to the second threshold value at each timing, and even if the difference value is less than the second threshold value, If it is determined that the difference value is greater than or equal to the second threshold, it is determined that the difference is in the step period. As a result, it is possible to avoid erroneously determining that the level difference is not a step even when noise occurs in the middle.

  In the eighth invention, by receiving a stop instruction to stop outputting the displacement amount, it becomes possible to arbitrarily set a period during which it is not necessary to output clearly.

  In the ninth aspect, by outputting the discrimination signal as a one-shot pulse signal having a constant time width, the discrimination result can be displayed for a fixed time, and the measured value can be easily viewed.

  In the tenth aspect of the invention, the displacement amount of the detection target is calculated based on the light reception signal of the light receiver sampled and acquired at a predetermined timing, and the step period and the step period that are step candidates are not formed based on the variation of the displacement amount. A non-step period is discriminated. A first representative value that represents one of the upper or lower steps of the step based on the displacement amount acquired during the step period, and a second that represents the other of the upper or lower steps based on the displacement amount acquired during the non-step period immediately before the step period. A step representative value is calculated based on the representative value. By comparing the step representative value calculated for each period determined as a step period with the first threshold to determine whether or not it is a step, the displacement per hour or sampling variation due to the step is compared. Even if it is moderate, it is possible to reliably detect the step by determining whether or not it is a step candidate, and to represent the representative value of each sampling value within the step candidate period and the step determination threshold (first step). (1 threshold value) and further discriminating the step, it is possible to eliminate variations due to other than the step. Therefore, it is possible to reliably detect the step even when the displacement per hour or the fluctuation per sampling due to the step is relatively gradual.

  According to the present invention, it is possible to detect a step with certainty by once determining whether or not it is a step candidate even when the amount of displacement due to the step is relatively gradual per sampling or sampling. In addition, by comparing the representative value of each sampling value within the step candidate period with the step determination threshold (first threshold) to further determine the step, it is possible to eliminate variations due to other than the step. Therefore, it is possible to reliably detect the step even when the displacement per hour or the fluctuation per sampling due to the step is relatively gradual.

It is a schematic diagram which shows the structure of the optical displacement sensor which concerns on Embodiment 1 of this invention. FIG. 3 is a three-view diagram illustrating a configuration example of a measurement head unit of the optical distance sensor of the triangulation system according to the first embodiment of the present invention. It is a top view which shows the structure of the controller part of the optical displacement sensor which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the optical displacement sensor which concerns on Embodiment 1 of this invention. It is a flowchart which shows the process sequence of the calculating part of the optical displacement sensor which concerns on Embodiment 1 of this invention. It is a figure which shows the relationship between the fluctuation | variation of the sampling value of a time series, and another value. It is a figure which shows the relationship between the fluctuation | variation of a time series sampling value, and other values when noise enters in the middle. It is a figure which shows the fluctuation | variation of the displacement amount in the case of conveying paper sheets in piles. It is a figure which shows the relationship between the fluctuation | variation of the sampling value of a time series, and another value when it remove | deviates from the measurement range in the middle. It is a figure which shows the relationship between the fluctuation | variation of a time-sequential sampling value, and another value when reset input is input. It is a figure which shows the relationship between the fluctuation | variation of a time-sequential sampling value, and another value when a timing input is input. It is a schematic diagram for demonstrating the automatic setting method of a 1st threshold value. It is a block diagram which shows the structure of the optical displacement sensor which concerns on Embodiment 2 of this invention. It is a flowchart which shows the process sequence of the calculating part of the optical displacement sensor which concerns on Embodiment 2 of this invention.

  Hereinafter, an optical displacement sensor according to an embodiment of the present invention will be described with reference to the drawings. Throughout the drawings to be referred, elements having the same or similar configuration or function are denoted by the same or similar reference numerals, and detailed description thereof is omitted.

(Embodiment 1)
FIG. 1 is a schematic diagram showing a configuration of an optical displacement sensor according to Embodiment 1 of the present invention. As shown in FIG. 1, the optical displacement sensor 1 according to the first embodiment includes the presence or absence of the workpiece A1 based on the reflected light L2 reflected by the irradiated projection light L1 on the surface of the workpiece (detection target) A1. It is a displacement sensor that detects a desired shape or the like of the workpiece A1. The optical displacement sensor 1 is a displacement detection device including a measurement head unit 2, a transmission cable 3, and a controller unit 4. The optical displacement sensor 1 detects the presence / absence of the workpiece A1 placed on the work table A2, the desired shape of the workpiece A1, and the like. To do.

  The measurement head unit 2 includes a projector 11 that irradiates the workpiece A1 with the projection light L1 and a light receiver 14 that receives the reflected light L2 that is reflected from the surface of the workpiece A1. The output of the projector 11 is adjusted based on the output of the light receiver 14. For example, the measurement head unit 2 is arranged on the production line of the workpiece A1, and irradiates the projection light L1 in the direction directly below.

  The transmission cable 3 serves as a communication line for supplying power to the measurement head unit 2 as a power supply line, transmitting the output of the light receiver 14 to the controller unit 4, and transmitting a control signal from the controller unit 4 to the measurement head unit 2. Function. As a communication method, any method can be used as long as data communication is possible, such as RS422 communication, RS232 communication, LVDS, Ethernet (registered trademark), in addition to RS485 communication. In addition, communication may be performed wirelessly instead of using the transmission cable 3.

  The controller unit 4 detects the position of the light receiving spot of the reflected light L2 received by the light receiver 14, and determines the presence / absence of the workpiece A1 and calculates the displacement amount based on the detected result. On one surface of the casing of the controller unit 4, various operation keys, the presence / absence of the workpiece A1, the display unit for displaying the result, and the like are arranged.

  The position of the light receiving spot based on the output of the light receiver 14 is configured to be triggered by a timing signal input from an external device such as a PLC (Programmable Logic Controller) (not shown). Also good.

  FIG. 2 is a three-view diagram illustrating a configuration example of the measurement head unit 2 of the triangular distance measuring optical displacement sensor 1 according to the first embodiment of the present invention. The measurement head unit 2 includes a light projector 11, a light projection lens 12, a light receiving lens 13, and a light receiver 14, and a head indicator 15 including LED indicator lights 15a to 15c is disposed on a side surface of the housing.

  The projector 11 is a light source device that generates the projection light L1, and includes a light emitting element such as an LD (laser diode) or an LED. The light projecting lens 12 is a condensing lens for condensing the projection light L <b> 1 irradiated from the light projector 11, and is disposed closer to the work A <b> 1 than the light projector 11. The projection light L1 that has passed through the light projection lens 12 is irradiated onto the workpiece A1 through a rectangular light projection window 2a provided on the front surface of the housing.

  The light receiving lens 13 is a condensing lens for condensing the reflected light L2 reflected on the surface of the work A1 by the projection light L1 applied to the work A1, and the reflected light L2 The light enters through the light receiving window 2b provided in the. In the light receiver 14, a plurality of light receiving elements that receive the reflected light L <b> 2 from the workpiece A <b> 1 are linearly arranged, and a signal corresponding to the amount of light received is output from each light receiving element. Specifically, a line CCD (Charge Coupled Device) in which a plurality of light receiving elements are arranged on a straight line is used as the light receiver 14. Of course, the imaging device is not limited to the line CCD, and other imaging devices such as CMOS or PSD may be used.

  The light emitted from the projector 11 to the work A1 is reflected by the surface of the work A1, and is condensed at different positions on the light receiver 14 according to the height of the irradiation point on the work A1, that is, the distance from the work table A2. To do. Note that an imaging element in which a plurality of light receiving elements are arranged in a planar shape may be used as the light receiver 14 as long as the change in the position of the light receiving spot on the light receiver 14 due to the change in the height of the irradiation point can be determined. .

  The LED indicator lamp 15a is an indicator lamp that indicates the output state of the projection light L1, and is configured by an LED (Light Emitting Diode). For example, the LED indicator lamp 15a is lit in green when the projection light L1 is being irradiated, and is turned off when the projection light L1 is not being irradiated. The LED indicator lamp 15b is an indicator lamp that indicates the sensor output state of the controller unit 4. For example, the LED indicator lamp 15b is turned off when the sensor output is in the on state, and is lit red when the sensor output is in the off state.

  The LED indicator lamp 15c is an indicator lamp that indicates the presence or absence of multiple reflection on the workpiece A1. For example, when the reflected light L2 reflected from the surface of the workpiece A1 includes multiple reflections, it lights in green and is due to multiple reflections. Turns off when does not contain.

  FIG. 3 is a plan view showing the configuration of the controller unit 4 of the optical displacement sensor 1 according to Embodiment 1 of the present invention. The controller unit 4 includes a display unit 21 including various LED indicator lamps 24, 25, 27, and 28 and a 7-segment LED display unit 26 on one surface of the housing. The LED indicator lamp 24 is an indicator lamp that indicates the irradiation state of the projection light L1, and is composed of LEDs. For example, the LED indicator lamp 24 lights in green when the projection light L1 is being irradiated, and turns off when the projection light L1 is not being irradiated.

  The LED indicator lamp 25 is an indicator lamp that indicates the sensor output state of the controller unit 4. For example, the LED indicator lamp 25 is turned off when the sensor output is in the on state, and is lit red when the sensor output is in the off state. The LED indicator lamp 27 is an indicator lamp showing an operation mode.

  The LED indicator lamp 28 is an indicator lamp that indicates the presence or absence of multiple reflection on the workpiece A1, for example, when the reflected light L2 reflected by the surface of the workpiece A1 includes multiple reflection, it lights in green and is due to multiple reflection. Turns off when does not contain.

  The 7-segment LED display unit 26 is a display device that displays a displacement amount or the like in characters, and is configured by six 7-segment LEDs arranged at the center in the display unit 21. Each 7-segment LED is arranged in the longitudinal direction on one surface of the housing.

  FIG. 4 is a block diagram showing a configuration of the optical displacement sensor 1 according to Embodiment 1 of the present invention, and an example of functional blocks in the controller unit 4 is also shown. The measurement head unit 2 includes a measurement unit 23 and a communication unit 22 that performs data communication with the controller unit 4. The controller unit 4 includes an arithmetic unit 41 that executes various arithmetic processes, a storage unit 42 that stores necessary information, a communication unit 43 that performs data communication with the measurement head unit 2, a display unit 21, and an inter-controller communication unit 46. Has been.

  The calculation unit 41 is configured by a microcomputer, a CPU, and the like. The storage unit 42 is composed of an EEPROM, a flash memory, etc., and determines whether or not it is a step period threshold (second threshold) 421 that determines whether or not it is a step candidate period, that is, a step period. The step determination threshold (first threshold) 422, the peak hold value 423 indicating the maximum displacement amount within the step period, and the reference displacement 424 are stored.

  Further, the inter-controller communication unit 46 exchanges information between the controller units 4 when two or more optical displacement sensors 1 are used. CAN communication, optical communication, or the like is used for communication between controllers, but is not particularly limited thereto, and is not particularly limited as long as data communication can be performed with each other.

  The displacement amount calculation unit 411 of the calculation unit 41 detects the position of the light receiving spot on the light receiver 14 based on the amount of light received by each light receiving element of the light receiver 14 shown in FIG. Based on this, the displacement amount of the workpiece A1 is calculated. Specifically, the amount of received light detected by the light receiving element is determined for each light receiving element, and a light receiving spot is extracted from the distribution of the one-dimensional position of the received light quantity in the arrangement direction of each light receiving element. A displacement amount is calculated based on the peak position or the gravity center position of the extracted light receiving spot. As the amount of displacement, the position of the irradiation point on the workpiece A1 in the optical axis direction of the projection light L1 is calculated.

  The sampling unit 412 samples the displacement amount calculated by the displacement amount calculation unit 411 at a predetermined timing, and the difference value calculation unit 413 calculates a difference value between the displacement amount sampled last time and the displacement amount sampled this time. Here, the “displacement amount sampled last time” may be not only the displacement amount sampled at the immediately preceding timing but also the displacement amount sampled a predetermined number of times before. Further, representative displacement amounts representing a plurality of displacement amounts calculated from displacement amounts sampled at a plurality of timings are also included in the “previously sampled displacement amount” in the present invention. The difference value may be a simple difference between the displacement amount sampled last time and the displacement amount sampled this time, or may be a value that takes into account the time difference between the time sampled last time and the time sampled this time.

  The step period determination unit (determination unit) 414 determines a step period and a non-step period based on the calculated difference value. More specifically, it is a method that captures fluctuations in the amount of displacement and recognizes the fluctuation period as a level difference. However, it is necessary to recognize the level difference by distinguishing fluctuations other than the level difference such as noise from fluctuations due to the level difference. is there. However, since it is difficult to set an appropriate threshold value for accurately determining the step, the step period determination unit 414 has a difference value larger than the second threshold value, including fluctuations due to other than the step such as noise. The period is determined as a step period. In addition, the timing at which the change in the amount of displacement has been determined as the start timing of the step period (at the start of the step period) so that the step period can be determined stably, and the timing at which the change in the amount of displacement can be considered to have settled It is discriminated from the end timing of the period. Here, “can be considered that the variation of the displacement amount has settled” means that, for example, a period in which the difference value does not exceed the second threshold continues for a predetermined time or a predetermined number of sampling times. There are two variations of displacement amount, positive direction and negative direction, but the direction of variation regarded as a step is determined in advance by the user's setting etc. Even if the absolute value of is large, it is considered that there is no change in the amount of displacement that should be determined to be a step if the direction of change is considered to be a step in the opposite direction.

  The reference displacement specifying unit 415 specifies the reference displacement in the period determined as the step period, and the step determining unit 416 compares the difference value between the current displacement and the reference displacement with the first threshold value to determine whether the step is a step. Determine whether or not. Specifically, the current displacement at the start of the step period is specified as the reference displacement. The output unit 417 outputs an ON / OFF state determination signal regarding whether or not it is a step, and displays it on the display unit 21. That is, the amount of displacement of the step is displayed on the display unit 21 configured with the 7-segment LED display unit 26 as a measured value. The output unit 417 may output an analog signal indicating the amount of displacement of the step displayed on the display unit 21 in addition to the determination signal regarding whether or not it is a step.

  Hereinafter, the operation of the optical displacement sensor 1 having the above-described configuration will be described. FIG. 5 is a flowchart showing a processing procedure of the calculation unit 41 of the optical displacement sensor 1 according to Embodiment 1 of the present invention.

  In FIG. 5, the calculation unit 41 of the optical displacement sensor 1 samples the displacement amount at a predetermined timing (step S501), and sets the current displacement as a reference displacement (step S502). Thereafter, the computing unit 41 samples the displacement amount at the next predetermined timing (step S503), and calculates a difference value between the displacement amount sampled last time and the displacement amount sampled this time (step S504).

  The calculating unit 41 determines whether or not the calculated difference value is equal to or greater than a second threshold (step S505). When the calculation unit 41 determines that the difference value is smaller than the second threshold (step S505: NO), the calculation unit 41 sets the current displacement as a new reference displacement (step S506), and the process is performed in step S503. The process described above is repeated.

  FIG. 6 is a diagram illustrating a relationship between a variation in time-series sampling values (amount of displacement sampled at each timing) and other values. The upper graph is a graph showing the transition of the sampling value, and the numerical value immediately below it indicates the sampling value at each timing. FIG. 6 shows a state in which sampling values transition in the order of 10, 15, 10, 25, 40, 55, 70. Correspondingly, the difference value between the displacement amount sampled last time and the displacement amount sampled this time becomes indefinite 5, 5, -5, 15, 15, 15, 15... (Not shown). In FIG. 6, the step determination threshold (first threshold) for determining whether or not the step is “50”, and the step period threshold (second threshold) for determining whether or not the step is “9”. It is said. Further, the time 61 at the time of one-shot output is 8 ms.

  As shown in FIG. 6, “5” and “−5”, which are smaller than the second threshold value “9”, are the difference values from the previous sampling value (previous sampling value) in the first three times after starting sampling. Alternatively, since it is indefinite, it is determined in step S505 that it is a non-step period or indefinite. As shown in FIG. 6, the “step period flag” indicates that “1” is during the step period, “0” is during the non-step period, and “−” is undefined. The “reference displacement” is updated each time the displacement at each time point, that is, the sampled value is changed during the non-step period. Thereby, the reference displacement can be made to follow a gradual change, and the influence of the change in the displacement amount due to other than the step can be reduced.

  The difference value of the sampling value in the fourth time (the difference value between the displacement amount sampled last time and the displacement amount sampled this time) is “15”, which is equal to or greater than the second threshold value “9”. It is determined that it is a step period, and a flag indicating that it is a step period is set (the “step period flag” is changed from “0” to “1”), and the tracking of the “reference displacement” is interrupted, that is, “ The “reference displacement” is maintained at the sampling value “10” of the third time immediately before. In other words, the “reference displacement” is maintained at a value representative of each sampling value in the non-step period immediately before the step period, in this example, the last sampling value “10” in the non-step period during the step period. become. The “difference value” shown in FIG. 6 is a value obtained by subtracting the reference displacement from the sampling value, and the “reference displacement” transitions to indefinite, 10, 15, 10, 10, 10, 10,. Therefore, the “difference value” transitions to indefinite, indefinite, −5, 15, 30, 45, 60.

  Returning to FIG. 5, when the calculation unit 41 of the optical displacement sensor 1 determines that the difference value is greater than or equal to the second threshold (step S505: YES), the calculation unit 41 then displaces at a predetermined timing. The amount is sampled (step S507), and it is determined whether any of the difference values from the displacement amount sampled within the predetermined number of times immediately before, for example, within 5 times is equal to or greater than the second threshold, that is, in step S505. It is determined whether or not it can be considered that the variation of the displacement amount has settled depending on whether or not it is determined to be YES at least once among the latest five determinations (step S508). When the calculation unit 41 determines that any difference value within the immediately preceding predetermined number of samplings is equal to or greater than the second threshold value, that is, when it is determined that the variation of the displacement amount has not yet settled (step S508: YES). The calculation unit 41 calculates a difference value between the sampled displacement amount and the reference displacement, and when the difference value exceeds the value stored in the storage unit 42 as the peak hold value, the calculated difference value is calculated. Is stored in the storage unit 42 as the peak hold value, and the peak hold value stored in the storage unit 42 is updated when the difference value does not exceed the value stored in the storage unit 42 as the peak hold value. Without (step S509), the process returns to step S507 and the above-described process is repeated.

When the calculation unit 41 determines that all the difference values within the immediately preceding predetermined number of samplings are all smaller than the second threshold value, that is, when it is determined that the variation of the displacement amount has settled (step S508: NO), it is stored. Since the peak hold value corresponds to the maximum fluctuation amount from the reference displacement, in order to determine whether or not the fluctuation is caused by a step, the calculation unit 41 has the stored peak hold value equal to or greater than the first threshold value. Is determined (step S510). When the calculation unit 41 determines that the stored peak hold value is greater than or equal to the first threshold value (step S510: YES), the calculation unit 41 outputs a determination signal indicating that it is a step (one shot) ( Step S511). When the calculation unit 41 determines that the stored peak hold value is smaller than the first threshold (step S510: NO), the calculation unit 41 resets the stored peak hold value to 0 (zero). (Step S512), the process is returned to step S503, and the above-described process is repeated.

  The peak hold value shown in FIG. 6 is 0 (zero) in the non-step period, and in the step period, 15, 30, as the sampling value or the difference value (a value obtained by subtracting the reference displacement from the sampling value) increases. Even when the sampling value or the difference value (the value obtained by subtracting the reference displacement from the sampling value) is decreased, it is the maximum value in the step period '90. 'Is maintained. In other words, the sampling value representative of the step period is obtained from the sampling values in the step period. In this example, the maximum sampling value '100' of the step period represents each sampling value of the step period. Corresponds to the sampling value. Then, based on the sampling value representative of the step period and the sampling value representative of the non-step period immediately before the step period, a step representative value indicating the step in the step period is obtained. A difference “90” between the maximum sampling value “100” and the reference displacement “10” that represents each sampling value in the non-step period immediately before the step period corresponds to the step representative value of the step period.

The “count number” shown in FIG. 6 is counted up when the difference value between the displacement amount sampled last time during the step period and the displacement amount sampled this time is smaller than the second threshold value “9”. If it is greater than or equal to the second threshold value '9', it is reset to 0 (zero). That is, it is determined whether or not the difference value is continuously smaller than the second threshold value “9”. In the example of FIG. 6, the sampling value (sampled displacement amount) transitions to 85, 100, 100, 60, 0, 0, 0, 0, 0, 0, 15. The difference value (not shown) between the sampled displacement amount and the currently sampled displacement amount is changed to 15, 15, 0, −40, −60, 0, 0, 0, 0, 0, 15. The count number changes as follows: 0, 0, 1, 2, 3, 4, 0, 0, 0, 0, 0. In this example, the number of consecutive times for determining that the step period has ended is four, and the timing at which the count number becomes “4” is determined as the timing at which the step period ends. In this example, the count number in the non-step period is set to 0 (zero).

By determining the timing from the start to the end of the step period, a value representative of each sampling value in the step period and a step representative value representative of the step in the step period are determined. The peak hold value (step representative value representative of the step in the step period) is compared with a step determination threshold (first threshold) for determining whether or not it is a step. In the example of FIG. Since the step representative value (“90” representing the step in the period) is greater than or equal to the step determination threshold (first threshold) “50”, it is determined that the change in the displacement amount during the step is due to the step. In this case, the peak hold value (step representative value representing the step in the step period) '90' is determined as the measurement value, and the determined measurement value is held until the measurement value is determined by determining the next step period. The In the example of FIG. 6, even when the step period is fixed, the measurement is performed when the peak hold value (step representative value representing the step in the step period) is smaller than the step determination threshold (first threshold). It goes without saying that the values are not updated, but may be configured to be updated.

The measured value is displayed on the display unit 21 and the peak hold value (step representative value representing the step in the step period) is compared with the step determination threshold (first threshold). If it is determined that the difference is due to the above, a determination signal indicating that the level difference is present is output for 8 ms, which is the time for one-shot output (ON state). When the output time of the discrimination signal (ON state time) exceeds 8 ms, the discrimination signal is automatically turned off.

  FIG. 7 is a diagram illustrating a relationship between time-series fluctuations in sampling values and other values when noise enters midway. In FIG. 7, as in FIG. 6, the step determination threshold (first threshold) for determining whether or not the step is “50”, and the step period threshold (second threshold) for determining whether or not the step is a step. Is set to '9'. The time for one-shot output is 8 ms. Note that definitions of terms such as “sampling value” in FIG. 7 are the same as those in FIG. 6 unless redefined.

  As shown in the second peak of FIG. 7, the noise value is moved up and down greatly with the step discrimination threshold value '50' sandwiched by the noise during sampling. Conventionally, it has been difficult to appropriately set a threshold value for distinguishing whether a variation in displacement is a variation due to noise or a variation due to a level difference. For example, when the threshold setting is inappropriate, peak hold In the state of the value “70”, there is a possibility that it is determined that the fluctuation is caused by a step. On the other hand, in the first embodiment, it is not determined that it is the step period until the difference value of the sampling value is stabilized based on the most recent predetermined difference value. In other words, since the second threshold value only determines a step period in which there appears to be a step and a non-step period that is other than that, it may be a step period including a period in which the displacement varies due to noise. A precise value is not required as the threshold value. Then, it is possible to accurately determine the step by determining whether or not the change in each step period is due to the step, based on the peak hold value that is the maximum amount of change in each step period from the reference displacement. . Further, the peak hold value '105' after the difference between the sampling values is stabilized is displayed as an output.

  6 and 7, the end of the step period is determined by whether or not each difference value from the immediately preceding sampling value is smaller than the step period threshold by a predetermined number of times. Therefore, the count number is reset when the count number reaches ‘4’, and the flag indicating the step period is set to 0 (zero). Then, the stored peak hold value is displayed on the display unit 21 as a measured value. In addition, a discrimination signal indicating that the level difference is present is output for 8 ms, which is the time for one-shot output (ON state). When 8 ms is exceeded, the determination signal is automatically turned off. Furthermore, in addition to the output line that outputs the discrimination signal, an output line that outputs an analog signal indicating the amount of displacement of the step displayed on the display unit 21 may be provided.

  In addition, since the displacement amount of the step displayed on the display unit 21 is maintained without being updated until the next step is detected, the display values such as the differential value and the displacement amount may be instantaneously updated. The measured value can be displayed reliably. Therefore, it becomes easy to visually recognize the size of the step that has been difficult to read in the past.

  FIG. 8 is a diagram illustrating a change in the amount of displacement when paper sheets are stacked and conveyed. As shown in FIG. 8A, even when the paper sheet 83 is conveyed by being overlapped by the belt conveyor 82, the discrimination signal is set as a one-shot output, for example, as shown in FIG. In addition, even when the rising fluctuation of the displacement amount 81 due to the step is relatively steep and the falling fluctuation is relatively gentle, each step can be detected reliably.

  If the measurement range is out of the way, the sampling value cannot be acquired. In this case, it is necessary to reset the reference displacement when returning to the measurement range. FIG. 9 is a diagram showing the relationship between the variation of the time-series sampling value and other values when the measurement range is out of the way. Also in FIG. 9, the step determination threshold (first threshold) for determining whether or not the step is “50”, and the step period threshold (second threshold) for determining whether or not the step is “9”. It is said. The time for one-shot output is 8 ms. Note that definitions of terms such as “sampling value” in FIG. 9 are the same as those in FIG. 6 unless redefined.

  As shown in the second peak of FIG. 9, the sampling value cannot be acquired because the sampling value deviates from the measurement range during sampling 91. In this case, since it corresponds by resetting the reference displacement again from the time when the acquisition of the sampling value is resumed, it is impossible to acquire the difference value for a while after the acquisition of the sampling value is resumed. Therefore, since no measurement value is output, no abnormal value is output.

  Further, a reset input may be used to reset the reference displacement to the current displacement (reset means). In this case, the displacement when the reset input is input is set as the reference displacement. FIG. 10 is a diagram illustrating the relationship between time-series sampling value fluctuations and other values when a reset input is input. Also in FIG. 10, the step determination threshold (first threshold) for determining whether or not the step is “50”, and the step period threshold (second threshold) for determining whether or not the step is “9”. It is said. The time for one-shot output is 8 ms. Note that definitions of terms such as “sampling value” in FIG. 10 are the same as those in FIG. 6 unless redefined.

  As shown in the pulse waveform of the reset input in FIG. 10, when the sampling value is sequentially acquired at the second peak and the reset input is input while the difference value is being calculated, the current value at the time when the reset input is input Displacement '45' is set as a reference displacement. In this case, since the stored peak hold value is small, the output value is also small.

  Furthermore, by accepting the timing input, the sampling value acquired at the desired timing can be ignored and the output can be stopped (stop instruction accepting means). FIG. 11 is a diagram illustrating the relationship between time-series fluctuations in sampling values and other values when a timing input is input. Also in FIG. 11, the step determination threshold (first threshold) for determining whether or not the step is “50”, and the step period threshold (second threshold) for determining whether or not the step is “9”. It is said. The time for one-shot output is 8 ms. Note that definitions of terms such as “sampling value” in FIG. 11 are the same as those in FIG. 6 unless redefined.

  As shown in the pulse waveform of the timing input in FIG. 11, the sampling value acquired based on the step of the period 111 in the on state is ignored, and when the off state is entered, the sampling value at that point is used as the reference displacement '100. Set as'. Thereby, about the part which does not need to output a measured value, it can prevent that a measured value is output by inputting a timing input.

  Note that the optical displacement sensor 1 may be configured to set a first threshold value based on a displacement amount measured according to a user instruction. More specifically, the optical displacement sensor 1 measures the amount of displacement corresponding to the lower stage of the step according to the user's instruction, and then measures the amount of displacement corresponding to the upper stage of the step according to the user's instruction. Thus, an intermediate value between the amount of displacement corresponding to the upper stage of the step and the amount of displacement corresponding to the lower stage of the step can be automatically set as the first threshold value.

  FIG. 12 is a schematic diagram for explaining the first threshold automatic setting method. As shown in FIG. 12A, first, a displacement 122 corresponding to the lower level of the step of the workpiece A1 is acquired and stored by the user operating the SET button or the like. Next, as shown in FIG. 12B, the displacement 123 corresponding to the upper level of the step of the work A1 is acquired and stored by the user operating the SET button or the like. Then, as shown in FIG. 12C, an intermediate value between the displacement amount 123 corresponding to the upper step of the workpiece A1 and the displacement amount 122 corresponding to the lower step of the step is set as the first threshold value 121. Needless to say, the first threshold value may be adjusted to an arbitrary value by the user after the automatic setting.

  Further, the second threshold value may have a fixed relationship with the first threshold value so that the second threshold value is automatically determined when the first threshold value is set. For example, a value that is 1/10 of the first threshold is set as the second threshold.

  The second threshold value may be adjusted according to the duration of the step period, the number of samplings, or the like, or may be configured to be adjusted in conjunction with the setting of the sampling period. . For example, when the sampling period is short, the value of 1/10 of the first threshold is set as the second threshold, and when the sampling period is long, the value of 1/3 of the first threshold is set as the second threshold. .

When the second threshold is configured to be set by the user, the display unit 21 displays the duration of each step period, the number of times of sampling, or the displacement amount sampled last time and the displacement sampled this time in each step step period. The maximum value and the minimum value of the difference value with respect to the amount may be displayed, and information useful for setting the second threshold value may be displayed to the user.

In addition, a step counting function for counting the number of steps determined may be provided.

  Although the separation type optical displacement sensor in which the measurement head unit 2 and the controller unit 4 are separated has been described, the present invention is an integrated optical displacement sensor in which the measurement head unit 2 and the controller unit 4 are integrated. It is also possible to apply to.

  As described above, according to the first embodiment, when the displacement amount is determined to be equal to or greater than the second threshold value, it is determined that the displacement period is the step period, and the displacement amount during the step period is equal to or greater than the first threshold value. It is possible to detect the step more reliably by reducing the influence of fluctuations in the displacement due to vibrations of the conveying device such as a belt conveyor, fluctuations in the displacement in the time direction, etc. Become.

(Embodiment 2)
Since the configuration of the optical displacement sensor 1 according to the second embodiment of the present invention is the same as that of the first embodiment, the same reference numerals are given to omit detailed description. In order to determine whether or not it is a step, the difference value between the reference displacement and the sampling value is not used, but the difference value between the current sampling value and the immediately preceding sampling value is integrated and used. This is different from Form 1.

  FIG. 13 is a block diagram showing a configuration of the optical displacement sensor 1 according to Embodiment 2 of the present invention, and an example of functional blocks in the controller unit 4 is also shown. The measurement head unit 2 includes a measurement unit 23 and a communication unit 22 that performs data communication with the controller unit 4. The controller unit 4 includes an arithmetic unit 41 that executes various arithmetic processes, a storage unit 42 that stores necessary information, a communication unit 43 that performs data communication with the measurement head unit 2, a display unit 21, and an inter-controller communication unit 46. Has been.

  The calculation unit 41 is configured by a microcomputer, a CPU, and the like. The storage unit 42 is configured by an EEPROM, a flash memory, or the like, and has a step period threshold (second threshold) 421 for determining whether or not it is a step period, and a step determination threshold (first threshold) for determining whether or not it is a step. , And a peak hold value 423 indicating the maximum value of the displacement amount within the step period.

  Further, the inter-controller communication unit 46 exchanges information between the controller units 4 when two or more optical displacement sensors 1 are used. CAN communication, optical communication, or the like is used for communication between controllers, but is not particularly limited thereto, and is not particularly limited as long as data communication can be performed with each other.

  The displacement amount calculation unit 411 of the calculation unit 41 detects the position of the light receiving spot on the light receiver 14 based on the amount of light received by each light receiving element of the light receiver 14 shown in FIG. Based on this, the displacement amount of the workpiece A1 is calculated. Specifically, the amount of received light detected by the light receiving element is determined for each light receiving element, and a light receiving spot is extracted from the distribution of the one-dimensional position of the amount of received light with respect to the arrangement direction of each light receiving element. A displacement amount is calculated based on the peak position or the gravity center position of the extracted light receiving spot. As the amount of displacement, the position of the irradiation point on the workpiece A1 in the optical axis direction of the projection light L1 is calculated.

  The sampling unit 412 samples the displacement amount calculated by the displacement amount calculation unit 411 at a predetermined timing, and the difference value calculation unit 413 calculates a difference value between the displacement amount sampled last time and the displacement amount sampled this time. The step period determination unit (determination unit) 414 determines a step period and a non-step period based on the calculated difference value.

  More specifically, it is a method that captures fluctuations in the amount of displacement and recognizes the fluctuation period as a level difference. However, it is necessary to recognize the level difference by distinguishing fluctuations other than the level difference such as noise from fluctuations due to the level difference. is there. However, since it is difficult to set an appropriate threshold value for accurate determination of a step, the step period determination unit 414 has a second difference value including a variation due to other than a step such as noise. A period larger than the threshold value is determined as a step period. In addition, the timing at which the change in the amount of displacement has been determined as the start timing of the step period (at the start of the step period) so that the step period can be determined stably, and the timing at which the change in the amount of displacement can be considered to have settled It is discriminated from the end timing of the period. Here, “can be considered that the variation of the displacement amount has settled” means that, for example, a period in which the difference value does not exceed the second threshold continues for a predetermined time or a predetermined number of sampling times. There are two variations of displacement amount, positive direction and negative direction, but the direction of variation regarded as a step is determined in advance by the user's setting etc. Even if the absolute value of is large, it is considered that there is no change in the displacement amount due to the step to be detected when the direction of the change is regarded as a step in the opposite direction.

  The difference integrating unit 418 calculates an integrated value of the difference values in the period determined as the step period, and the step determining unit 416 calculates the maximum integrated value calculated for each period determined as the step period and the first threshold value. To determine whether or not it is a step. The output unit 417 outputs an ON / OFF determination signal related to whether or not it is a step and displays it on the display unit 21. That is, the amount of displacement of the step is displayed on the display unit 21 configured with the 7-segment LED display unit 26 as a measured value.

  Hereinafter, the operation of the optical displacement sensor 1 having the above-described configuration will be described. FIG. 14 is a flowchart showing a processing procedure of the calculation unit 41 of the optical displacement sensor 1 according to Embodiment 2 of the present invention.

  In FIG. 14, the calculation unit 41 of the optical displacement sensor 1 samples the displacement amount at a predetermined timing (step S1401), samples the displacement amount at the next predetermined timing (step S1402), and the displacement sampled immediately before. A difference value between the amount (displacement amount sampled last time) and the displacement amount sampled this time is calculated (step S1403).

  The calculating unit 41 determines whether or not the calculated difference value is equal to or greater than a second threshold (step S1404). When the calculation unit 41 determines that the difference value is smaller than the second threshold (step S1404: NO), the calculation unit 41 returns the process to step S1402 and repeats the above-described process.

  When the calculation unit 41 determines that the difference value is greater than or equal to the second threshold (step S1404: YES), the calculation unit 41 integrates the calculated difference value (step S1405). Here, the timing at which the displacement amount fluctuates is determined as the start timing of the step period (step point start time), and the difference value is calculated based on the displacement amount sampled immediately before (displacement amount sampled last time). The last sampling value in the non-step period immediately before the step period corresponds to a value representing each sampling value in the non-step period immediately before the step period.

  The computing unit 41 samples the displacement amount at the next predetermined timing (step S1406), and any of the difference values from the displacement amount sampled within the previous predetermined number of times, for example, within 5 times, is greater than or equal to the second threshold value. It is determined whether or not there is (step S1407). When the calculation unit 41 determines that any difference value based on the amount of displacement sampled within the immediately preceding predetermined number of times is greater than or equal to the second threshold (step S1407: YES), the calculation unit 41 calculates the calculated difference value. (Step S1408), the integrated integrated value is stored in the storage unit 42 as a peak hold value (step S1409), the process returns to step S1406, and the above-described process is repeated. Note that the integrated value obtained by integrating the calculated difference values corresponds to the first and last acquired sampling values that are sequentially offset in the middle, and the first sampling value is the non-step difference immediately before the step period. This is the last sampling value in the period, and the last sampling value corresponds to the maximum sampling value in the step period. Therefore, the peak hold value of the integrated value obtained by integrating the calculated difference values corresponds to the step representative value. To do.

  When the calculation unit 41 determines that all the difference values based on the displacement amount sampled within the predetermined number of times immediately before are smaller than the second threshold value (step S1407: NO), the calculation unit 41 stores the peak hold value stored. Is greater than or equal to the first threshold (step S1410). When the calculation unit 41 determines that the stored peak hold value is greater than or equal to the first threshold value (step S1410: YES), the calculation unit 41 outputs a determination signal indicating that it is a step (one shot) ( Step S1411). When the calculation unit 41 determines that the stored peak hold value (step difference representative value) is smaller than the first threshold (step S1410: NO), the calculation unit 41 stores the accumulated value and peak hold value. Is reset to 0 (step S1412), the process returns to step S1402, and the above-described process is repeated.

  In the second embodiment as well, as in FIGS. 9 to 11, measurement can be continued even when the measurement range is out of range, and reset input and timing input can be utilized.

  As described above, according to the second embodiment, the displacement amount can be obtained as an integrated value of the difference values, and it is determined that the step period is from the time point when the obtained displacement amount is determined to be equal to or greater than the second threshold value. The threshold value for determining whether the change in the displacement amount is due to the vibration of the transport device or the step difference by determining that the displacement amount is a step when the displacement amount in the step period is equal to or greater than the first threshold value. Can be set relatively easily, and even if the step is very small, it can be reliably detected. In addition, since the measured value can be displayed reliably, it becomes easy to visually recognize the size of the step that has been difficult to read in the past.

  The present invention is not limited to the above-described embodiments, and various changes and improvements can be made within the scope of the present invention.

1 Optical displacement sensor 2 Measuring head
4 Controller unit 11 Projector 14 Receiver 21 Display unit 41 Calculation unit 42 Storage unit

Claims (12)

In an optical displacement sensor that irradiates a detection object with projection light and receives reflected light reflected by the detection object using a light receiver to obtain a displacement amount of the detection object.
Displacement amount calculating means for calculating a displacement amount of the detection object based on a light reception signal of the light receiver obtained by sampling at a predetermined timing; and
Difference value calculating means for calculating a difference value between the displacement amount sampled last time and the displacement amount sampled this time;
A discriminating means for discriminating a step period and a non-step period based on the calculated difference value;
A difference integration means for calculating an integrated value of the difference values in the period determined as the step period;
A step determining means for comparing the maximum value of the integrated value calculated for each period determined as the step period and a first threshold to determine whether or not the step is a step;
An optical displacement sensor comprising: output means for outputting a determination signal regarding whether or not a step.   2. The optical displacement sensor according to claim 1, further comprising display means for displaying an integrated value of the difference values calculated in the period determined as the step period.   3. The optical displacement sensor according to claim 1, further comprising a reset unit that resets an integrated value of the difference values calculated in the period determined as the step period to zero. In an optical displacement sensor that irradiates a detection object with projection light and receives reflected light reflected by the detection object using a light receiver to obtain a displacement amount of the detection object.
Displacement amount calculating means for calculating a displacement amount of the detection object based on a light reception signal of the light receiver obtained by sampling at a predetermined timing; and
Difference value calculating means for calculating a difference value between the displacement amount sampled last time and the displacement amount sampled this time;
A discriminating means for discriminating a step period and a non-step period based on the calculated difference value;
Reference displacement specifying means for specifying a reference displacement in a period determined as the step period;
A step determining means for comparing the difference value between the current displacement and the reference displacement with a first threshold to determine whether or not it is a step;
An optical displacement sensor comprising: output means for outputting a determination signal regarding whether or not a step.   5. The optical displacement sensor according to claim 4, further comprising reset means for resetting the reference displacement to a current displacement in a period determined as the step period.   The determination means determines whether or not the difference value is greater than or equal to a second threshold at each timing, and determines that a period determined to be greater than or equal to the second threshold is a step period. The optical displacement sensor according to any one of claims 1 to 5, wherein:   The determination means determines whether or not the difference value is equal to or greater than a second threshold value at each timing, and even if it is determined that the difference value is less than the second threshold value, 6. The optical displacement according to claim 1, wherein when it is determined that the difference value is equal to or greater than the second threshold value, it is determined that the difference period is a step period. 6. Sensor.   The optical displacement sensor according to any one of claims 1 to 7, further comprising stop instruction receiving means for receiving a stop instruction for stopping outputting the displacement amount.   9. The optical displacement sensor according to claim 1, wherein the output unit outputs the determination signal as a one-shot pulse signal having a certain time width. In an optical displacement sensor that irradiates a detection object with projection light and receives reflected light reflected by the detection object using a light receiver to obtain a displacement amount of the detection object.
Displacement amount calculating means for calculating a displacement amount of the detection object based on a light reception signal of the light receiver obtained by sampling at a predetermined timing; and
A discriminating means for discriminating a step period and a non-step period based on a change in the displacement amount;
A first representative value representing one of the upper or lower steps of the step based on the displacement amount acquired during the step period, and a first representative value representing the other of the upper or lower steps based on the displacement amount acquired during the non-step period immediately before the step period. Step calculating means for calculating a step representative value based on the two representative values;
A step determining means for comparing the step representative value calculated for each period determined as the step period and a first threshold to determine whether or not it is a step;
An optical displacement sensor comprising: output means for outputting a determination signal regarding whether or not a step. In a step detection method in an optical displacement sensor that irradiates a detection object with projection light and receives reflected light reflected by the detection object using a light receiver to obtain a displacement amount of the detection object.
Calculating a displacement amount of the detection object based on a light reception signal of the light receiver obtained by sampling at a predetermined timing;
Determining a step period and a non-step period based on a difference value of the calculated displacement amount;
Calculating an integrated value of difference values in the period determined as the step period;
Comparing the maximum value of the integrated value calculated for each period determined as the step period and a first threshold value to determine whether or not it is a step;
And a step of outputting a determination signal regarding whether or not it is a step. In a step detection method in an optical displacement sensor that irradiates a detection object with projection light and receives reflected light reflected by the detection object using a light receiver to obtain a displacement amount of the detection object.
Calculating a displacement amount of the detection object based on a light reception signal of the light receiver obtained by sampling at a predetermined timing;
Determining a step period and a non-step period based on a difference value of the calculated displacement amount;
Identifying a reference displacement in a period determined as the step period;
Comparing the difference value between the current displacement and the reference displacement with a first threshold value to determine whether or not it is a step;
And a step of outputting a determination signal regarding whether or not it is a step.

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