JP5638904B2 - Distance measuring device and distance measuring method - Google Patents

Description

  The present invention relates to a distance measuring apparatus and a distance measuring method for measuring a distance to a measurement target by irradiating a measurement target with a light projection beam and receiving reflected light from the measurement target.

Conventionally, for example, as disclosed in Patent Document 1, a light projecting element that irradiates a measurement target with a light projection beam and a light receiving element that receives reflected light from the measurement target are measured based on the output of the light receiving element. A distance measuring device that calculates the distance to an object is widely known.
Such a distance measuring device is used, for example, to measure the distance to the body of an automobile that is provided in an automobile production line and is fixed at a predetermined position, and to detect each accuracy of the body including the installation accuracy. It has been.

Japanese Patent Laid-Open No. 07-301519

However, in the distance measuring apparatus as described above, although the distance to the measurement target is the same, a different distance may be measured depending on the surface state of the irradiated region of the projection beam. Specifically, the surface condition is uneven, such as the roughness of the irradiated area of the projection beam is different, the irradiated area is scratched, and the color depends on how the light from the surface is illuminated. If there is a difference in taste, the reflectivity changes and the measurement results vary.
As described above, the conventional distance measuring apparatus has a problem that a measurement error occurs depending on the surface state of the measurement target.

  An object of the present invention is to provide a distance measuring device and a distance measuring method capable of reducing a measurement error caused by a surface state of a measurement target.

The invention according to any one of claims 1 to 4 includes a light projecting element that emits light and irradiates a measurement target with a light projection beam, and a detection unit that includes a light receiving element that receives reflected light from the measurement target and the detection A casing in which the means is fixed, a linear motion guide unit that slidably supports the casing, a movable actuator that moves the detection means, and a process that calculates the distance to the measurement object based on the output of the light receiving element And a distance measuring device provided with a means.
On the premise of the above configuration, in the first aspect of the present invention, the casing to which the detection means is fixed is such that the light projecting element and the light receiving element are parallel to the measurement object with respect to the linear motion guide unit. The movable actuator reciprocally moves the casing along the linear guide unit, and the processing means reciprocates the light projecting element and the light receiving element in parallel. , Calculating distances to a plurality of different measurement sites around the target measurement site in the measurement target, and based on the calculated distances to the plurality of different measurement sites, the distance to the measurement target in the target measurement site Can be calculated.

In the invention of 請 Motomeko 1, wherein specific configuration of the movable actuator is not particularly limited, for example, a stepping motor, various motors and such a pulse motor or gear motor, an electromagnetic solenoid can be considered.

According to a second aspect of the present invention, the movable actuator periodically moves the detection unit, and the processing unit moves the detection beam to the measurement target while the detection unit moves for one cycle. Irradiation and reception of reflected light from the measurement object are performed a plurality of times.
According to a third aspect of the present invention, the processing means calculates a distance to a measurement object a plurality of times at a predetermined interval during driving of the movable actuator, and outputs an average value of the plurality of calculation results. Features .
The invention described in 請 Motomeko 4 includes a motor constituting the movable actuator, and a eccentric roller provided on an output shaft of said motor, said casing by rotational displacement of 1mm or 2mm of the eccentric roller linear It moves along a motion guide unit.

The invention described in claims 5 and 6 includes a step of generating light from a light projecting element and irradiating a measurement beam with a light projection beam, a step of receiving reflected light from the measurement target by a light receiving element, and the light receiving And a step of calculating a distance to a measurement object based on the output of the element.
On the basis of the above method, the invention according to claim 5 is directed to a linear motion guide unit that slidably supports a casing to which a detecting means including the light projecting element and the light receiving element is fixed, and the light projecting element and The light-receiving element and the light-receiving element are made parallel to the measurement object by moving the casing, in which the light-receiving element is movable in a direction parallel to the measurement object, by reciprocating linear movement along the linear motion guide unit by a movable actuator. A distance to a plurality of different measurement sites around the target measurement site in the measurement target in a state in which the light projecting device and the light receiving device are reciprocated in parallel. And calculating the distance to the measurement object in the target measurement part based on the calculated distances to the different measurement parts. And wherein the door.
The invention described in claim 6 further includes a step of outputting an average value of distances to the measurement object calculated a plurality of times.

Also, in the invention described in claim 5 and 6, aspects namely spot shape projection beam generated by the light emitting element is not specifically limited, in may be a so-called spot beam line beam There may be.

According to the first and fifth aspects of the present invention, since distances are measured at a plurality of parts of the measurement target, measurement errors caused by unevenness, scratches, or color differences appearing on the surface of the measurement target are reduced. , Ki out to improve the measurement accuracy, because the detection means can be moved automatically, it is possible to simplify the measurement operation. Further, since the casing is moved linearly, the structure can be simplified. In particular, according to the second aspect of the invention, since the measurement at a plurality of parts is automatically performed while periodically moving the detection means, the measurement work can be further simplified.
In particular, according to the invention described in claim 3 and claim 6 , the measurement at a plurality of parts is automatically performed, and the average value of a plurality of measurement results is output, so that the analysis of the measurement results is easy. Become.
In particular, according to the fourth aspect of the present invention, since the casing moves linearly only by driving the motor, the structure can be further simplified.

It is a figure which shows the body precision measuring apparatus with which the distance measuring apparatus of this invention is applied. It is the figure which looked at the body accuracy measuring device from the left side. It is the figure which looked at the body accuracy measuring device from the upper part. It is a top view of a distance measuring device, (a) is a front view, (b) is a (b) arrow view in (a), (c) is a (c) arrow view in (a). It is a three-view figure which shows a movable plate. It is a three-plane figure which shows a fixed plate. It is a three-plane figure which shows a motor fixing bracket. It is a three-plane figure which shows a transmission plate. It is a block diagram which shows the processing mechanism of a distance measuring device. It is a flowchart which shows the process of distance measurement. It is a figure which shows the modification of a distance measuring device.

A body accuracy measuring apparatus to which the present invention is applied will be described with reference to FIGS.
The body accuracy measuring apparatus 100 shown in FIG. 1 measures the accuracy of body installation, and the measurement space S is partitioned by iron fences arranged in a U-shape. In the measurement space S, a support base (not shown) for fixing the body of the automobile assembled in the production line is provided. The body B of the automobile that has completed the building process is transported to the measurement space S by the transport device and supported by the support base.

  In the body accuracy measuring device 100 described above, a plurality of imaging devices and the distance measuring device of the present invention are attached to the iron fence that forms the measurement space S. Accuracy is measured mechanically. Here, as shown in FIG. 3, the distance measuring device 1 located on the side of the body B supported by the support base is attached to the body accuracy measuring device 100. This distance measuring device 1 measures the distance to the body B that is the measurement target, and the installation accuracy of the body B is measured by the measured distance. Below, the structure of this distance measuring device 1 is demonstrated in detail.

  As shown in FIG. 4, the distance measuring device 1 has a detection means having a sensor and a substrate fixed in the casing 2. The detection means accommodated in the casing 2 includes a light projecting element 3 that generates light and irradiates a measurement target with a light projection beam, and a light receiving element 4 that receives reflected light from the measurement target. The casing 2 is formed with a light projecting portion 3a and a light receiving portion 4a, and a light projecting beam generated from the light projecting element 3 is output from the light projecting portion 3a to the outside of the casing 2 and measured. Reflected light from the target is input to the light receiving element 4 in the casing 2 from the light receiving portion 4a.

As is clear from FIGS. 4B and 4C, the casing 2 is fixed to the mounting surface 5a of the movable plate 5 made of a flat plate member in a surface contact state. Specifically, as shown in FIG. 5, a pair of mounting holes 6 are formed diagonally on the movable plate 5, and the casing 2 is attached to the movable plate 5 by screws (not shown) inserted through the mounting holes 6. It is fixed to the mounting surface 5a.
Further, four lock holes 7 penetrating from the attachment surface 5a side to the back surface 5b side are formed in the movable plate 5 at a predetermined interval. The lock hole 7 is for fixing the linear motion guide unit 8 shown in FIG. Specifically, the linear motion guide unit 8 is formed with four screw holes 8a corresponding to the lock holes 7 of the movable plate 5, and the lock holes 7 and the screw holes 8a are aligned with each other. By fastening a screw (not shown) from the attachment surface 5 a side, the linear motion guide unit 8 is fixed to the back surface 5 b of the movable plate 5.

As shown in FIG. 4A, the linear motion guide unit 8 has a pair of screw holes 8b. The screw holes 8b are for fixing the linear motion guide unit 8 to the fixing plate 9, and are located between the screw holes 8a. As shown in FIG. 6, the fixed plate 9 is configured by a flat plate member having an area smaller than that of the movable plate 5, and a pair of lock holes 10 are formed near the center thereof. The lock hole 10 corresponds to the screw hole 8b of the linear motion guide unit 8, and the screw hole 8b in a state where the lock hole 10 of the fixed plate 9 and the screw hole 8b of the linear motion guide unit 8 are aligned. By fastening a screw (not shown) from the side, the linear motion guide unit 8 is fixed to the fixed plate 9.
Thereby, one surface of the linear motion guide unit 8 is fixed to the movable plate 5, and the other surface is fixed to the fixed plate 9. In other words, the linear motion guide unit 8 is interposed between the movable plate 5 and the fixed plate 9, and the linear motion guide unit 8 guides the reciprocating linear motion of the movable plate 5 relative to the stationary plate 9. Become.

A pair of motor fixing holes 11 is formed near one side of the fixing plate 9. The motor fixing hole 11 is for fixing the motor fixing bracket 12 shown in FIG. 7, and the mounting hole 12a of the motor fixing bracket 12 and the motor fixing hole 11 are aligned with each other by a screw (not shown). Both will be fixed.
The motor fixing bracket 12 includes a fixing portion 12b in which a mounting hole 12a is formed and a protruding portion 12c formed continuously with the fixing portion 12b. A motor holding portion 12d that bends 90 degrees from 12c is provided.
As shown in FIG. 4A, the motor fixing bracket 12 protrudes outward from the opposing surfaces of the fixed plate 9, the movable plate 5 and the casing 2 when fixed to the fixed plate 9. The part 12c and the motor holding part 12d are positioned.

An electric motor M constituting the movable actuator of the present invention is fixed to the motor holding portion 12d. As is clear from FIG. 4A, the electric motor M is held by the motor holding portion 12d with the main body along the sides of the casing 2, the movable plate 5 and the fixed plate 9.
The motor holding portion 12d has a through hole 12e. When the electric motor M is held by the motor holding portion 12d, the output shaft 13 of the electric motor M passes through the through hole 12e. Yes.

The output shaft 13 of the electric motor M is also maintained parallel to the sides of the casing 2, the movable plate 5 and the fixed plate 9. An eccentric roller 14 is provided at the tip of the output shaft 13. ing. The eccentric roller 14 is provided with its center point shifted from the axis of the output shaft 13 by about 1 mm to 2 mm.
A transmission plate 15 is fitted on the outer periphery of the eccentric roller 14. As shown in FIG. 8, the transmission plate 15 includes a fitting portion 15a having a U-shaped cross section and a fixing portion 15b continuous to the fitting portion 15a.

As shown in FIGS. 4A and 4B, the outer periphery of the eccentric roller 14 is fitted into the fitting portion 15a in a close contact state, and the fixed portion 15b is formed on the back surface 5b of the movable plate 5. It is fixed to the fastening member 16.
Therefore, when the eccentric roller 14 rotates, the transmission plate 15 performs a reciprocating linear motion, and the movable plate 5 performs a reciprocating linear motion with respect to the fixed plate 9 together with the transmission plate 15. Since the casing 2 in which the light projecting element 3 and the light receiving element 4 are housed is fixed to the movable plate 5, the light projecting element 3 and the light receiving element 4 are integrally formed by driving the electric motor M. A reciprocating linear motion will be performed.

  When the distance measuring device 1 having the above configuration is used for the body accuracy measuring device 100, the light projecting unit 3a and the light receiving unit 4a are made to face the measurement site of the body B, and the light projecting unit 3a and the light receiving unit 4a. However, it attaches so that it may move in parallel with respect to the measurement site | part of the body B. FIG. Then, the electric motor M is driven, and the distance is measured in a state where the casing 2, that is, the light projecting element 3 and the light receiving element 4 are reciprocated in parallel with respect to the measurement site. Below, the process at the time of measuring a distance is demonstrated in detail.

FIG. 9 is a block diagram of a control device that performs distance measurement. The control device 50 serving as the processing means of the present invention includes a calculation unit configured by various programs stored in a CPU and a ROM, and a storage unit configured by a RAM.
The light receiving element 4 is connected to the input side of the control device 50, and a detection signal is input from the light receiving element 4 to the control device 50. An input unit 51 is connected to the input side of the control device 50. The input unit 51 is configured by, for example, a switch that can be operated by an operator, and a measurement start signal is input to the control device 50 when starting a distance measurement.

In addition, the electric motor M, the light projecting element 3, and the output unit 52 are connected to the output side of the control device 50. When the measurement start signal is input from the input unit 51, the control device 50 drives the electric motor M or projects a light projection beam from the light projecting element 3. The output unit 52 outputs the analysis / calculation result of the detection signal input from the light receiving element 4, and displays the analysis / calculation result on the screen or paper, or outputs the sound. It is.
The control device 50 may be provided in the casing 2 together with the detection means having the light projecting element 3 and the light receiving element 4, or provided outside the casing 2 and connected to the detection means via a cable. Also good.

  Next, distance measurement processing executed by the control device 50 will be described with reference to FIG. The distance measurement process shown in FIG. 10 is started when a measurement start signal is input from the input unit 51.

(Step S1)
When the measurement start signal is input, the control device 50 energizes and drives the electric motor M. As a result, the casing 2 starts to reciprocate in parallel with the measurement site of the body B.

(Step S2)
Next, the control device 50 generates light from the light projecting element 3 to irradiate the measurement site of the body B, which is the measurement target, with the projection beam.

(Step S3)
Next, the control device 50 analyzes the reflected light input to the light receiving element 4 and stores the analysis result in the storage unit.

(Step S4)
Next, the control device 50 stores a value obtained by adding “1” to the number of analyzes (N) stored in the storage unit as a new number of analyzes (N). At the time of starting measurement, the number of analyzes (N) = 0 is stored in the storage unit, and the analysis is repeated until the number of analyzes (N) reaches “100”.

(Step S5)
Next, the control device 50 determines whether or not the number of analyzes (N) stored in the storage unit is “100”. As a result, if it is determined that the number of analyzes (N) = 100, the process proceeds to step S8. If it is determined that the number of analyzes (N) is not “100”, the process proceeds to step S6.

(Step S6)
When it is determined in step S5 that the number of analyzes (N) is not “100”, the control device 50 sets a counter value corresponding to T time (for example, 0.01 seconds) in the timer counter. The T time set here is an interval time for analyzing the light reception result N times. That is, here, the analysis of the light reception result is performed a total of N times every T time.

(Step S7)
Next, the control device 50 determines whether or not the counter value set in the timer counter in step S6 is “0”. The counter value set in the timer counter is subtracted, and the process is repeated until the counter value reaches “0”, and the process waits. When the counter value = 0, the light reception result is analyzed again. Therefore, the process is moved to step S3. Thereby, the processing of step S3 to step S7 is repeatedly performed every T time, and when the analysis of the light reception result is performed 100 times, the processing is moved to step S8.

(Step S8)
When analysis of the light reception result is performed 100 times and it is determined in step S5 that the number of analyzes (N) = 100, the control device 50 resets the number of analyzes (N) stored in the storage unit. To do.

(Step S9)
Next, the calculation unit of the control device 50 calculates an average value of 100 analysis results stored in the storage unit.

(Step S10)
Next, the control device 50 outputs the calculation result of step S9 to the output unit 52. Note that it is desirable to set a specified range in advance and report an error in the output unit 52 when the calculation result is out of the specified range.

(Step S11)
Next, the control device 50 stops energization of the electric motor M and stops driving.

(Step S12)
Next, the control apparatus 50 stops the light projection from the light projecting element 3, and complete | finishes the said process.

According to the above processing, the light reception results of a plurality of times are acquired in the process in which the light projecting element 3 and the light receiving element 4 are moving in parallel with respect to the body B as the measurement target. Therefore, since measurement is performed on a plurality of different measurement sites and the distance is measured by the average value, measurement errors caused by unevenness and scratches appearing on the surface of the measurement target are reduced, and measurement accuracy is improved. Can do.
In the above embodiment, the control device 50 automatically analyzes every T time. However, for example, when the operation signal is input from the input unit 51 while the electric motor M is being driven, the light reception result is displayed. You may make it analyze and memorize.

Moreover, the structure of the distance measuring apparatus 1 in the above embodiment is merely an example, and the design can be changed as appropriate within a range in which the object of the present invention can be realized. For example, you may make it provide the further structure like the modification shown in FIG.
That is, in the distance measuring device according to this modification, the temperature measuring unit 60 including a seat heater, the heat insulating unit 61, and the temperature detecting unit 62 including a temperature sensor are further attached to the distance measuring device 1 of the above embodiment.

Specifically, the casing 2 is provided with a temperature adjusting means 60 on a predetermined surface thereof, and the outer periphery of the other surface is covered with a heat insulating means 61. Further, the temperature detecting means 62 is provided on a surface different from the surface on which the temperature adjusting means 60 is provided so that the heat of the temperature adjusting means 60 is not directly affected.
The temperature adjusting means 60 and the temperature detecting means 62 are electrically connected to the control device 50, and the control device 50 controls the temperature adjusting means 60 so that the temperature detected by the temperature detecting means 62 is constant. To maintain.

According to this modification, the control for reducing the measurement error due to the difference in the surface state and the control for reducing the measurement error due to the temperature change are realized by one control device 50, so that the cost is low. It is possible to improve the accuracy of distance measurement.
In the above embodiment, the light projecting element 3 and the light receiving element 4 integrally reciprocate linearly. However, the light projecting element 3 and the light receiving element 4 are integrally formed on the body B as a measurement target. It is only necessary to move while maintaining a substantially parallel state, and to irradiate the projection beam for distance measurement and to receive the reflected light multiple times during the movement. Not limited to this, periodic continuous movements such as a pendulum-like reciprocating movement, a circular movement, and an 8-shaped movement may be used as long as a plurality of positions around the target portion in the measurement target can be continuously measured.
Further, in the above-described embodiment, the case where the present invention is applied to an automobile body accuracy measuring apparatus has been described. However, the apparatus and the measurement target to which the present invention can be applied are not limited thereto, and are widely applied when measuring a distance. Is possible.

DESCRIPTION OF SYMBOLS 1 Distance measuring device 2 Casing 3 Light projection element 4 Light receiving element 8 Linear motion guide unit 13 Output shaft 14 Eccentric roller 50 Control apparatus M Electric motor

Claims (6)

A light projecting element that emits light and irradiates a measurement beam with a light projecting beam, and a detection means having a light receiving element that receives reflected light from the measurement target;
A casing to which the detection means is fixed;
A linear motion guide unit that slidably supports the casing;
A movable actuator for moving the detection means;
In the distance measuring device comprising: processing means for calculating the distance to the measurement object based on the output of the light receiving element;
The casing to which the detection means is fixed is provided such that the light projecting element and the light receiving element can move in a direction parallel to the measurement object with respect to the linear motion guide unit .
The movable actuator causes the casing to reciprocate linearly along the linear motion guide unit,
The processing means calculates distances to a plurality of different measurement sites around the target measurement site in the measurement target in a state where the light projecting element and the light receiving element are reciprocated in parallel, A distance measuring apparatus capable of calculating a distance to the measurement target in the target measurement part based on a distance to a different measurement part. The movable actuator periodically moves the detection means,
It said processing means, according to claim 1, characterized by performing a plurality of times receiving a reflected light from the irradiation and the measurement target of the projection light beam of the measuring object while the detecting means is moved one cycle Distance measuring device. 3. The distance according to claim 2 , wherein the processing unit calculates a distance to a measurement object a plurality of times at a predetermined interval while driving the movable actuator, and outputs an average value of the calculation results of the plurality of times. measuring device. A motor constituting the movable actuator;
An eccentric roller provided on the output shaft of the motor,
The 1mm to 2mm said casing by rotational displacement of the eccentric roller distance measuring apparatus according to claim 1, wherein the travel along the linear motion guide unit. A step of generating light from a light projecting element and irradiating a measurement beam with a light projecting beam;
Receiving a reflected light from the measurement object by a light receiving element;
A step of calculating a distance to a measurement object based on the output of the light receiving element, and a distance measuring method comprising:
The light projecting element and the light receiving element are movable in a direction parallel to the measurement object with respect to a linear motion guide unit that slidably supports a casing to which a detecting means including the light projecting element and the light receiving element is fixed. A step of moving the light projecting element and the light receiving element integrally in a direction parallel to a measurement object by reciprocating linearly moving the casing provided along the linear motion guide unit by a movable actuator; and the light projecting element And in a state where the light receiving element is reciprocated in parallel, the distance to a plurality of different measurement sites around the target measurement site in the measurement target is calculated, and based on the calculated distances to the plurality of different measurement sites And a step of calculating a distance to the measurement target at the target measurement site. 6. The distance measuring method according to claim 5 , further comprising a step of outputting an average value of distances to the measurement object calculated a plurality of times.

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