WO2019058678A1 - Distance measuring device and mobile body provided with same - Google Patents

Abstract

This distance measuring device is provided with: a light projection unit that outputs, toward a subject to be measured, projection light that is pulsed light; a disturbance light detection sensor that detects the intensity of disturbance light that is different from the projection light; a light receiving unit, which receives the disturbance light, and the projection light reflected by the subject, and which converts the light into an electrical signal; a comparison unit, which compares the level of the electrical signal of the projection light with a predetermined threshold value, and performs binarization; a distance measuring unit that measures, on the basis of the comparison results obtained from the comparison unit, the distance to the subject; and a threshold variable unit that varies the threshold value in accordance with the intensity of the disturbance light.

Description

Distance measuring device and mobile body provided with the same

The present invention relates to a distance measuring device and a movable body provided with the same.

For example, Patent Document 1 discloses a distance measuring device for a vehicle mounted on a vehicle (mobile body). This distance measuring apparatus for vehicles has an irradiating means, a receiving means, a propagation delay time measuring means, and a distance calculating means. The irradiation means generates and irradiates an electromagnetic wave. The receiving means receives a reflected wave of the electromagnetic wave reflected by the obstacle and generates a received signal. The propagation delay time measuring means holds a comparison value (threshold level) which is set such that the value used as the comparison reference is larger when the propagation delay time from irradiation to reception is shorter than when the propagation delay time is long. At this time, the comparison value is determined in advance based on the light reception signal due to disturbance such as fog and rain.

Then, the propagation delay time measuring means compares the reception signal with the comparison value to recognize the time when the reception signal becomes equal to or more than the comparison value as the reception detection time point, and propagation from the time when the irradiating means emits to the reception detection time point. Clock the delay time. The distance calculating means calculates the distance between the obstacle and the vehicle based on the propagation delay time.

JP-A-8-304535

However, according to the conventional distance measuring apparatus for vehicles (distance measuring apparatus), the comparison value may be set high in advance. In this case, even when the light reception signal due to the actual disturbance is small at the time of distance measurement, the comparison value is maintained high, and the light reception signal by the reflected wave of the electromagnetic wave at the obstacle (measurement object) is relatively small. There is a fear. Further, in the above-described conventional distance measuring device for a vehicle, when the comparative value is set in consideration of disturbance light such as sunlight, for example, the comparative value may be set high in advance. For this reason, the distance measurement of the distance measuring device for vehicles becomes inaccurate, and there existed a problem to which the reliability of the distance measuring device for vehicles fell.

An object of the present invention is to provide a distance measuring device capable of improving the reliability and a movable body provided with the same.

An exemplary distance measurement device according to the present invention includes a light projecting unit that emits projected light that is pulse light toward a measurement target, and a disturbance light detection sensor that detects the intensity of disturbance light that is different from the projected light. A light receiving unit that receives the disturbance light and the projection light reflected by the measurement object and converts the light into an electric signal; and a comparison unit that compares the level of the electric signal of the projection light with a predetermined threshold value and binarizes And a distance measurement unit that measures the distance to the measurement object based on the comparison result of the comparison unit, and a threshold value variable unit that changes the threshold according to the intensity of the disturbance light.

An exemplary mobile according to the present invention comprises the distance measuring device of the above configuration.

According to the exemplary distance measuring device and mobile unit of the present invention, the reliability can be improved.

FIG. 1 is a perspective view of an automatic guided vehicle provided with a distance measuring device according to an embodiment of the present invention. FIG. 2 is a side view of an automatic guided vehicle provided with the distance measuring device according to an embodiment of the present invention. FIG. 3 is a plan view of the automatic guided vehicle provided with the distance measuring device according to the embodiment of the present invention as viewed from above. FIG. 4 is a side cross-sectional view of a distance measuring device according to an embodiment of the present invention. FIG. 5 is a block diagram showing an electrical configuration of the distance measuring device according to the embodiment of the present invention. FIG. 6 is a waveform diagram showing an electrical signal after amplification by the amplification unit of the distance measuring device according to the embodiment of the present invention. FIG. 7 is a waveform diagram of an electric signal in the case where the electric signal of the light received by the light receiving unit is amplified without cutting the direct current component in the presence of disturbance light. FIG. 8 is a block diagram showing the electrical configuration of the automatic guided vehicle according to the embodiment of the present invention. FIG. 9 is a block diagram showing an electrical configuration of a distance measuring device according to a modification of the embodiment of the present invention.

Exemplary embodiments of the present invention will be described below with reference to the drawings. Here, an example in which the distance measuring device is configured as a laser range finder will be described. Moreover, as a mobile body which mounts a distance measurement apparatus, the unmanned conveyance vehicle which is an application which conveys a luggage | load is mentioned as an example, and is demonstrated. An unmanned carrier is also generally referred to as an AGV (Automated Guided Vehicle).

<1. General Configuration of Unmanned Transportation Vehicle> FIG. 1 is a perspective view of an unmanned transportation vehicle 15 provided with a distance measurement device 7 according to an embodiment of the present invention. FIG. 2 is a side view of an unmanned transfer vehicle 15 provided with a distance measurement device 7 according to an embodiment of the present invention. FIG. 3 is a plan view of the unmanned transfer vehicle 15 provided with the distance measurement device 7 according to an embodiment of the present invention as viewed from above. The unmanned transfer vehicle 15 travels autonomously by two-wheel drive and transports a load. In particular, the AGV 15 can rotate on the spot.

The unmanned transfer vehicle 15 includes a vehicle body 1, a loading platform 2, support portions 3L and 3R, drive motors 4L and 4R, drive wheels 5L and 5R, driven wheels 6F and 6R, and a distance measurement device 7. .

The vehicle body 1 is composed of a base 1A and a base 1B. The plate-like base portion 1B is fixed to the upper rear surface of the base 1A. The pedestal portion 1B has a triangular portion Tr projecting forward. The plate-like loading platform 2 is fixed to the upper surface of the platform 1B. A load can be placed on the upper surface of the loading platform 2. The loading platform 2 extends further to the front than the platform 1B. Thus, a gap S is formed between the front of the base 1A and the front of the loading platform 2.

The distance measuring device 7 is disposed at a position in front of the apex of the triangular portion Tr of the pedestal 1B in the gap S. The distance measuring device 7 is configured as a laser range finder, and measures a distance to a measurement object while scanning a laser beam. The distance measuring device 7 is used for map information creation and self-position identification to be described later. The detailed configuration of the distance measuring device 7 itself will be described later.

The support 3L is fixed on the left side of the base 1A and supports the drive motor 4L. The drive motor 4L is constituted by an AC servomotor as an example. The drive motor 4L incorporates a reduction gear (not shown). The drive wheel 5L is fixed to the rotating shaft of the drive motor 4L.

The support 3R is fixed on the right side of the base 1A and supports the drive motor 4R. The drive motor 4R is formed of an AC servomotor as an example. The drive motor 4R incorporates a reduction gear (not shown). The drive wheel 5R is fixed to the rotating shaft of the drive motor 4R.

The driven wheel 6F is fixed to the front of the base 1A. The driven wheel 6R is fixed to the rear of the base 1A. The driven wheels 6F, 6R passively rotate according to the rotation of the drive wheels 5L, 5R.

The unmanned transfer vehicle 15 can be moved forward and backward by rotationally driving the drive wheels 5L, 5R by the drive motors 4L, 4R. Further, by controlling the rotational speeds of the drive wheels 5L and 5R to be different, the unmanned transfer vehicle 15 can be rotated clockwise or counterclockwise to change its direction.

The control unit U, the battery B, and the communication unit T are housed inside the base 1A. The control unit U is connected to the distance measuring device 7, the drive motors 4L and 4R, the communication unit T, and the like.

The control unit U communicates various signals with the distance measuring device 7 as described later. The control unit U also performs drive control of the drive motors 4L and 4R. The communication unit T communicates with an external tablet terminal (not shown), and conforms to Bluetooth (registered trademark), for example. Therefore, the unmanned transfer vehicle 15 can be remotely controlled by the tablet terminal. The battery B is configured of, for example, a lithium ion battery, and supplies power to each unit such as the distance measurement device 7, the control unit U, the communication unit T, and the like.

<2. Configuration of Distance Measuring Device> FIG. 4 is a side sectional view of the distance measuring device 7. The distance measuring device 7 configured as a laser range finder has a substantially cylindrical casing 80 extending in the vertical direction in appearance. A laser light source 71, a collimating lens 72, a light projecting mirror 73, a light receiving lens 74, a light receiving mirror 75, a band pass filter 76, a light receiving portion 77, and a rotating case 78 inside the housing 80; A motor 79, a substrate 81, a wiring 82, and a disturbance light detection sensor 83 are accommodated.

The laser light source 71 is mounted on the lower surface of the substrate 81 fixed to the lower surface of the upper end portion of the housing 80. The laser light source 71 emits downward laser light L1 (projected light) of pulsed light in, for example, an infrared region (about 905 nm). In the present embodiment, the laser light L1 emitted from the laser light source 71 has a rectangular shape in a plane orthogonal to the optical axis.

The collimator lens 72 is disposed below the laser light source 71. The collimator lens 72 emits the laser light L1 emitted from the laser light source 71 downward as parallel light.

Below the collimator lens 72, a light projecting mirror 73 is disposed. The projection mirror 73 is fixed to the rotating housing 78. The rotating housing 78 is fixed to the shaft 79 A of the motor 79 and is rotationally driven by the motor 79 around the rotation axis J. Along with the rotation of the rotation housing 78, the light projection mirror 73 is also rotationally driven around the rotation axis J. The light projection mirror 73 reflects the laser beam L1 transmitted through the collimator lens 72 on the reflection surface 73a, and projects the reflected laser beam L1 to the outside of the housing 80. Since the light projection mirror 73 is rotationally driven as described above, the laser light L1 is emitted while changing the emission direction in the range of 360 degrees around the rotation axis J. At this time, the laser beam L1 has a rectangular shape in a plane orthogonal to the optical axis. Therefore, the above-described shape of the laser beam L1 emitted to the outside of the automatic guided vehicle 15 with the rotation of the rotary housing 78 rotates from one of the vertically long state and the horizontally long state to the other.

The laser light source 71 and the light projecting mirror 73 constitute a light projecting unit that emits the laser light L1 which is pulse light toward the object to be measured.

The housing 80 has a transmitting portion 801 midway in the vertical direction. The transmitting portion 801 is made of a translucent resin or the like.

The laser beam L1 reflected by the reflection surface 73a of the light projection mirror 73 passes through the transmission portion 801, passes through the gap S (see FIG. 2), and is emitted to the outside from the unmanned transfer vehicle 15. In the present embodiment, as shown in FIG. 3, the predetermined scan rotation angle range θ is set to 270 degrees around the rotation axis J as an example. More specifically, the range of 270 degrees includes 180 degrees forward and 45 degrees respectively to the left and right. The laser beam L1 passes through the transmission portion 801 at least in the range of 270 degrees around the rotation axis J. Note that the laser beam L1 is blocked by the inner wall of the housing 80, the wiring 82, or the like in a range in which the rear transmission portion 801 is not disposed.

The light receiving mirror 75 is fixed to the rotating housing 78 at a position below the light projecting mirror 73. The light receiving lens 74 is fixed to the circumferential side surface of the rotary housing 78. The band pass filter 76 has a dielectric multilayer film, is positioned below the light receiving mirror 75, and is fixed to the rotating housing 78. The light receiving unit 77 is located below the band pass filter 76 and is fixed to the rotating housing 78.

The laser beam L1 emitted from the distance measuring device 7 is reflected by the object to be measured and becomes diffused light. A part of the diffused light sequentially passes through the gap S and the transmitting portion 801 as incident light L 2 and enters the light receiving lens 74. That is, the incident light L2 is a part of the laser light L1 reflected by the measurement object. The incident light L2 transmitted through the light receiving lens 74 enters the light receiving mirror 75 and is reflected downward by the light receiving mirror 75. The incident light L 2 reflected by the light receiving mirror 75 is transmitted through the band pass filter 76 and received by the light receiving unit 77. At this time, the band pass filter 76 transmits only light in the wavelength band of the incident light L2. In the present embodiment, the band pass filter 76 transmits only light in the infrared region.

The light receiving unit 77 converts the received incident light L2 and disturbance light AL into an electrical signal by photoelectric conversion. Specifically, the light receiving unit 77 converts the intensity of the received incident light 2 and the disturbance light AL into a current value.

The disturbance light detection sensor 83 is adjacent to the light receiving unit 77, and detects the intensity of the disturbance light AL. The disturbance light AL is, for example, light from the sun SN (sunlight), illumination light in a room where the automated guided vehicle 15 moves, or the like. Sunlight and illumination light are continuous light. Here, continuous light refers to light whose output is substantially constant with respect to time, and pulse light refers to light such that the peak of the output repeatedly appears at a predetermined cycle.

The position of the disturbance light detection sensor 83 is not limited to the position adjacent to the light receiving unit 77, and may be a position at which the intensity of disturbance light can be detected. Further, the disturbance light detection sensor 83 only needs to detect the DC signal of the disturbance light AL, and can be configured at a lower cost than the light receiving unit 77.

When the rotary housing 78 is rotationally driven by the motor 79, the light receiving lens 74, the light receiving mirror 75, the band pass filter 76, the light receiving unit 77 and the disturbance light detection sensor 83 are rotationally driven together with the light projecting mirror 73.

As shown in FIG. 3, a range formed by rotating at a predetermined radius around the rotation axis J in the scanning rotation angle range θ (= 270 degrees) is defined as a measurement range Rs. When the laser beam L1 is emitted in the scanning rotation angle range θ and the laser beam L1 is reflected by the measurement object located in the measurement range Rs, the reflected laser beam L1 is transmitted as the incident beam L2 through the transmitting portion 801. Then, the light enters the light receiving lens 74.

The motor 79 is connected to the substrate 81 by the wiring 82 and is rotationally driven by being energized from the substrate 81. The motor 79 rotates the rotating housing 78 at a predetermined rotational speed. For example, the rotating housing 78 is rotationally driven at about 3000 rpm. The wiring 82 is routed around the rear inner wall of the housing 80 along the vertical direction.

<3. Electrical Configuration of Distance Measurement Device> Next, the electrical configuration of the distance measurement device 7 will be described. FIG. 5 is a block diagram showing the electrical configuration of the distance measuring device 7.

The distance measuring device 7 includes a laser light emitting unit 701, a laser light receiving unit 702, a distance measuring unit 703, an arithmetic processing unit 704, a data communication interface 705, a driving unit 706, a motor 79, and a disturbance light detection sensor 83. And a storage unit 712. A laser light emitting unit 701, a laser light receiving unit 702, a distance measuring unit 703, a data communication interface 705, a driving unit 706, a disturbance light detection sensor 83, and a storage unit 712 are connected to the arithmetic processing unit 704. Further, the laser light receiving unit 702 is connected to the distance measuring unit 703, and the motor 79 is connected to the driving unit 706.

The laser emission unit 701 has a laser light source 71 (see FIG. 4), an LD driver (not shown) for driving the laser light source 71, and the like. The LD driver is mounted on the substrate 81 (see FIG. 4).

The laser light receiving unit 702 includes a light receiving unit 77, a DC component cutting unit 707, a current-voltage conversion unit 708, an amplification unit 709, and a comparison unit 710.

The direct current component cutting unit 707 is formed of, for example, a capacitor, and cuts the direct current component (DC component) of the electric signal (current) generated by the photoelectric conversion of the light receiving unit 77. The current-voltage converter 708 has, for example, a transimpedance amplifier, and converts the current generated by photoelectric conversion of the light receiver 77 into a voltage.

The amplification unit 709 has an auto gain control amplifier and amplifies an electrical signal (voltage). The comparison unit 710 has a comparator, and compares the level of the electric signal (voltage) of the incident light L2 with a predetermined threshold SL to binarize the level into a high level and a low level. Then, the comparison unit 710 outputs the binarized measurement pulse to the distance measurement unit 703.

Distance measurement section 703 receives the measurement pulse output from comparison section 710. The laser emission unit 701 emits a laser beam L1 using a laser emission pulse output from the arithmetic processing unit 704 as a trigger. When the emitted laser light L1 is reflected by the measurement object OJ, the incident light L2 is received by the laser light receiving unit 702. A measurement pulse is generated according to the amount of light received by the laser light receiving unit 702, and the measurement pulse is output to the distance measurement unit 703.

Here, the reference pulse output together with the laser emission pulse from the arithmetic processing unit 704 is input to the distance measuring unit 703. The distance measuring unit 703 can acquire the distance to the measurement object OJ by measuring the elapsed time from the rising timing of the reference pulse to the rising timing of the measurement pulse. That is, the distance measurement unit 703 measures the distance by the so-called TOF (Time Of Flight) method. The measurement result of the distance is output from the distance measurement unit 703 as measurement data. As described above, the distance measurement unit 703 measures the distance to the measurement object OJ based on the comparison result of the comparison unit 710.

The drive unit 706 controls the rotation of the motor 79. The motor 79 is rotationally driven by the drive unit 706 at a predetermined rotational speed. The arithmetic processing unit 704 outputs a laser emission pulse each time the motor 79 rotates by a predetermined unit angle. For example, the predetermined unit angle is one degree. Thus, the laser light emitting unit 701 emits light each time the rotating housing 78 and the light projecting mirror 73 rotate by a predetermined unit angle, and the laser light L1 is emitted.

Arithmetic processing unit 704 is based on the orthogonal coordinate system based on distance measuring device 7 based on the rotational angle position of motor 79 at the timing when the laser emission pulse is output and the measurement data obtained corresponding to the laser emission pulse. Generate location information for That is, based on the rotation angle position of the light projection mirror 73 and the measured distance, the position of the measurement object OJ is acquired. The acquired position information is output from the arithmetic processing unit 704 as measurement distance data. Thus, the distance image of the measurement object OJ can be acquired by scanning with the laser beam L1 in the scanning rotation angle range θ.

The amount of light received by the laser light receiving unit 702 is changed by the reflectance of light at the measurement target OJ. For example, when the measurement target object OJ is a black object and the light reflectance decreases, the light reception amount decreases and the rising of the measurement pulse is delayed. Then, the distance measurement unit 703 measures the distance longer. As described above, the light reflectance of the measurement object OJ causes the measured distance to change even if the distance is actually the same. Here, when the light reception amount decreases, the length of the measurement pulse becomes short. Therefore, the arithmetic processing unit 704 corrects the measurement data according to the length of the measurement pulse to improve the distance measurement accuracy. The arithmetic processing unit 704 uses the corrected measurement data when generating measurement distance data.

The measured distance data output from the arithmetic processing unit 704 is transmitted to the unmanned transfer vehicle 15 shown in FIG. 6 described later via the data communication interface 705.

Further, the arithmetic processing unit 704 has a threshold variable unit 711. The threshold variable unit 711 changes the threshold SL in accordance with the intensity of the disturbance light AL.

The storage unit 712 stores a table in which the intensity of the disturbance light AL is associated with the threshold value SL. For example, in the table, the threshold SL increases as the intensity of the disturbance light AL increases.

<4. Operation of Distance Measuring Device> In the distance measuring device 7 configured as described above, when the laser light L1 is emitted from the laser light source 71 (see FIG. 4), the laser light L1 passes through the collimating lens 72 and becomes parallel light. The light is reflected by the reflection surface 73 a of the mirror 73. The laser beam L1 reflected by the reflective surface 73a is projected to the outside of the housing 80.

The laser beam L1 reflected by the measurement object OJ becomes incident light L2, passes through the light receiving lens 74, is reflected by the light receiving mirror 75, passes through the band pass filter 76, and enters the light receiving unit 77. The disturbance light AL also passes through the light receiving lens 74, is reflected by the light receiving mirror 75, passes through the band pass filter 76, and is incident on the light receiving unit 77. At this time, part of the disturbance light AL reflected by the light receiving mirror 75 enters the disturbance light detection sensor 83. Thereby, the intensity of the disturbance light AL is detected.

The incident light L2 and disturbance light AL incident on the light receiving unit 77 are converted into an electrical signal (current) by the light receiving unit 77. Next, the direct current component cut portion 707 cuts the direct current component of the electric signal (current). Here, the electrical signal (current) of the disturbance light AL, which is continuous light, corresponds to a DC component. For this reason, the level of the electrical signal (current) corresponding to the disturbance light AL can be significantly reduced by the direct current component cut portion 707.

Next, the current-voltage converter 708 converts the current (electric signal) generated by the photoelectric conversion of the light receiver 77 into a voltage (electric signal). Thereafter, the voltage is amplified by the amplification unit 709.

FIG. 6 is a waveform diagram showing the electrical signal (voltage) amplified by the amplification unit 709. As shown in FIG. The vertical axis shows amplitude (unit: mV), and the horizontal axis shows time (unit: ns). A reference pulse (not shown) is input at 0 ns, and a measurement pulse Pa is generated at 60 to 70 ns. Further, in the present embodiment, the threshold SL (the low setting value SL1) when the intensity of the disturbance light AL is sufficiently small is set to about 50 mV. That is, the threshold value SL when the disturbance light AL hardly enters the light receiving unit 77 is set to about 50 mV.

As shown in FIG. 6, the amplitude of the measurement pulse Pa is about 520 mV. On the other hand, when the electric signal (voltage value) is amplified after cutting the direct current component of the electric signal (current), the amplitude of the electric signal resulting from the disturbance light is about 180 mV on average. Therefore, when the comparing unit 710 compares the level of the electric signal of the incident light L2 with the low setting value SL1, not only the incident light L2 but also the disturbance light AL is determined to be the high level. Therefore, accurate binarization can not be performed, and the distance measurement by the distance measurement device 7 becomes inaccurate.

Therefore, in the present embodiment, the threshold value changing unit 711 changes the threshold value SL in accordance with the intensity of the disturbance light AL. Specifically, the threshold value variable unit 711 raises the threshold value SL from the low setting value SL1 (about 50 mV) to the high setting value SL2 (about 200 mV). As a result, the electrical signal of the disturbance light AL and the electrical signal of the incident light L2 are clearly determined to be Low level and High level, respectively, and accurate binarization is performed. Therefore, the distance measuring device 7 can perform distance measurement accurately.

At this time, since the distance measuring device 7 includes the storage unit 712 (see FIG. 5) that stores a table in which the intensity of the disturbance light AL is associated with the threshold value SL, the threshold value changing unit 711 can easily change the threshold value SL. Can.

FIG. 7 is a diagram showing the waveforms of electric signals corresponding to the incident light L2 and the disturbance light AL when the current is converted into a voltage by the current-voltage conversion unit 708 without cutting the direct current component. The amplitude corresponding to the DC component D is about 300 mV. On the other hand, the amplitude of the peak of the measurement pulse Pa is about 510 mV. When the DC component D is cut, the amplitude of the electrical signal of the disturbance light AL decreases to near 0 mV, and the amplitude of the peak of the measurement pulse Pa also decreases to about 200 mV. Then, when the electric signal (voltage) is amplified by the amplification unit 709 so that the amplitude of the peak of the measurement pulse Pa becomes about 510 mV again, the state of FIG. 7 is obtained.

When the intensity of the disturbance light AL is sufficiently smaller than the incident light L2, only the direct current component D is cut by the direct current component cut unit 707, and the threshold value change unit 711 does not have to change the threshold value SL. .

<5. Electrical Configuration of Unmanned Transportation Vehicle> The electrical configuration of the distance measurement device 7 has been described as described above. Here, the electrical configuration of the unmanned transportation vehicle 15 will be described with reference to FIG. FIG. 8 is a block diagram showing the electrical configuration of the automatic guided vehicle 15.

The unmanned transfer vehicle 15 includes a distance measuring device 7, a control unit 8, a drive unit 9, a power button 10, and a communication unit T. The distance measurement device 7, the drive unit 9, the communication unit T, and the power button 10 are connected to the control unit 8.

The control unit 8 is provided in the control unit U (see FIG. 1). The drive unit 9 has a motor driver (not shown), drive motors 4L, 4R, and the like. The motor driver is provided in the control unit U. The control unit 8 issues a command to the drive unit 9 to control it. The drive unit 9 drives and controls the rotational speeds and rotational directions of the drive wheels 5L and 5R.

The control unit 8 communicates with a tablet terminal (not shown) via the communication unit T. For example, the control unit 8 can receive an operation signal corresponding to the content operated on the tablet terminal via the communication unit T.

The power button 10 is an operation button for turning on the unmanned transfer vehicle 15 for activation.

The control unit 8 receives the measured distance data output from the distance measuring device 7. The control unit 8 can create map information based on the measured distance data. The map information is information generated to perform self-position identification for specifying the position of the unmanned carrier 15. The map information is generated as position information of a stationary object at a location where the unmanned carrier 15 travels. For example, when the unmanned transfer vehicle 15 travels in a warehouse, the stationary object is a wall of the warehouse, a shelf arranged in the warehouse, or the like.

The map information is generated, for example, when a manual operation of the automatic guided vehicle 15 is performed by a tablet terminal. In this case, an operation signal corresponding to the operation of, for example, a joystick of the tablet terminal is transmitted to the control unit 8 through the communication unit T, and the control unit 8 instructs the drive unit 9 according to the operation signal. The traveling control of the carrier 15 is performed. At this time, based on the measured distance data input from the distance measuring device 7 and the position of the unmanned transfer vehicle 15, the control unit 8 specifies the position of the measurement object at the location where the unmanned transfer vehicle 15 travels as map information. . The position of the unmanned transfer vehicle 15 is identified based on the drive information of the drive unit 9.

The map information generated as described above is stored by the storage unit 85 of the control unit 8. The control unit 8 compares the measured distance data input from the distance measuring device 7 with the map information stored in advance in the storage unit 85 to identify the position of the unmanned transfer vehicle 15 itself. Do. By performing the self position identification, the control unit 8 can perform autonomous traveling control of the unmanned transfer vehicle 15 along a predetermined route.

<6. Operation of Unmanned Transportation Vehicle> Next, operations of the unmanned transportation vehicle 15 and the distance measuring device 7 will be described. When the power button 10 is operated, the control unit 8 controls the power from the battery B to be supplied to each unit except the distance measuring device 7 shown in FIG. Thereby, traveling of the unmanned carrier 15 is started. At the same time, the control unit 8 controls power supply from the battery B to be supplied to the distance measuring device 7, and activates the distance measuring device 7.

When the map information is created, as described above, the control unit 8 instructs the drive unit 9 according to the manual operation on the tablet terminal, for example, to control the traveling of the unmanned transfer vehicle 15. When the manual operation for moving the rectilinear movement is performed, the control unit 8 instructs the driving unit 9 to move the unmanned transfer vehicle 15 rectilinearly at a predetermined speed and a predetermined direction (forward or reverse). In addition, when the manual operation for causing the rotation operation is performed, the control unit 8 causes the driving unit 9 to rotate the unmanned transfer vehicle 15 at a predetermined rotation speed, a predetermined rotation angle, and a predetermined rotation direction (clockwise or counterclockwise). Give a command to

Further, when the unmanned carrier 15 travels autonomously while performing self-location identification based on the map information after creation, the control unit 8 autonomously instructs the drive unit 9 to make the unmanned carrier 15 Are moved straight or rotated as described above.

In the distance measuring device 7, the arithmetic processing unit 704 starts outputting the measured distance data to the unmanned transfer vehicle 15 via the data communication interface 705. At the time of map information creation, the control unit 8 creates map information based on the measured distance data acquired from the distance measuring device 7. Further, at the time of self-position identification, the control unit 8 specifies the position of the unmanned transfer vehicle 15 based on comparison of the measured distance data acquired from the distance measuring device 7 with the existing map information.

<7. Modification of this Embodiment> FIG. 9 is a block diagram showing an electrical configuration of a distance measurement device 7 according to a modification of this embodiment. The distance measurement device 7 may have a derivation unit 713 instead of the storage unit 712. The deriving unit 713 is connected to the arithmetic processing unit 704, and derives an approximate curve that approximates the relationship between the intensity of the disturbance light AL and the threshold value SL. The derived approximate curve is stored in the arithmetic processing unit 704. As a result, the threshold value SL can be derived from the intensity of the disturbance light AL by interpolation, and it is possible to save time and effort in advance creating a table in which the intensity of the disturbance light AL and the threshold value SL are associated. In addition, the increase of the capacity of the storage unit or the like for holding the table can be reduced.

In addition, when the peak value of the incident light L2 binarized by the comparison unit 710 is lower than a predetermined value, the threshold value changing unit 711 may change the threshold value SL. For example, the threshold value changing unit 711 raises the threshold value SL, but raises the threshold value SL again if the binarization is insufficient.

<8. Functions and effects of the present embodiment> According to the distance measurement device 7 of the present embodiment, the light emitting unit that emits the laser light L1 (projected light) that is pulse light toward the measurement object OJ is different from the laser light L1. The disturbance light detection sensor 83 for detecting the intensity of the disturbance light AL, the light receiving unit 77 for receiving the disturbance light AL and the laser light L1 reflected by the measurement object OJ and converting it into an electric signal, and the electric signal of the incident light L2 A comparison unit 710 that compares the level with a predetermined threshold value SL and binarizes the distance measurement unit 703 that measures the distance to the measurement object OJ based on the comparison result of the comparison unit 710, and the intensity of disturbance light AL And a threshold value variable unit 711 that changes the threshold value SL accordingly.

Thereby, even when disturbance light AL (for example, sunlight or illumination light) different from the laser light L1 is incident on the light receiving unit 77, the threshold value SL is changed according to the intensity of the disturbance light AL to generate noise due to the disturbance light AL. The impact can be reduced. Further, when the intensity of the disturbance light AL is small, the threshold value SL is not set high, and therefore, the electric signal of the incident light L2 may not be evaluated relatively low. Therefore, the distance measuring device 7 can accurately measure the distance to the measurement object OJ, and the reliability of the distance measuring device can be improved.

The threshold variable unit 711 increases the threshold SL as the intensity of the disturbance light AL increases. Thereby, in the distance measurement of the distance measurement device 7, the influence by sunlight or illumination light can be reduced.

The distance measuring device 7 includes a direct current component cutting unit 707 that cuts a direct current component (DC component) of the electric signal generated by photoelectric conversion of the light receiving unit 77, and an amplification unit 709 that amplifies the electric signal (voltage). . Thereby, the influence of noise of disturbance light AL can be removed more.

The disturbance light detection sensor 83 is adjacent to the light receiving unit 77. Thereby, the disturbance light detection sensor 83 can detect the intensity of the disturbance light AL incident on the light receiving unit 77 more accurately.

When the peak value of the incident light L2 binarized by the comparison unit 710 is lower than a predetermined value, the threshold value changing unit 711 may change the threshold value SL. Thereby, the binarization can be performed more clearly, and the distance to the measurement object OJ can be measured more accurately.

The distance measurement device 7 includes a storage unit 712 that stores a table in which the intensity of the disturbance light AL is associated with the threshold value SL. Thereby, the distance measurement device 7 can easily change the threshold value SL.

The distance measurement device 7 may include a derivation unit 713 for deriving an approximate curve that approximates the relationship between the intensity of the disturbance light AL and the threshold value SL. Thereby, the distance measurement device 7 can easily change the threshold value SL. Further, the threshold value SL corresponding to the intensity of the disturbance light AL can be easily derived by interpolation, and it is possible to save time and effort in advance creating a table in which the intensity of the disturbance light AL and the threshold value SL are associated. In addition, the increase of the capacity of the storage unit or the like for holding the table can be reduced.

The unmanned transfer vehicle 15 (moving body) includes a distance measuring device 7. Thereby, the unmanned transfer vehicle 15 provided with the distance measuring device 7 capable of improving the reliability can be easily realized.

<9. Others> Although the embodiments of the present invention have been described above, various modifications can be made to the embodiments within the scope of the present invention.

For example, in the above embodiment, although the unmanned transfer vehicle 15 has been described as an example of the moving body, the present invention is not limited thereto, and the moving body may be applied to devices other than transport applications such as a cleaning robot and a monitoring robot . Also, the moving body may be configured by a passenger car. In this case, the distance measuring device 7 may be mounted on the lower front of the passenger car, and the distance measuring device 7 may measure the distance to an obstacle or the like in front of the passenger car.

Further, the band pass filter 76 may be omitted from the present embodiment. Thereby, an increase in the pulse width of the electrical signal corresponding to the incident light L2 can be suppressed, and the distance measuring device 7 can measure the distance more accurately.

The present invention can be used, for example, for a distance measuring device and a mobile unit equipped with the same.

DESCRIPTION OF SYMBOLS 1 ... Vehicle body, 1A ... base, 1B ... stand part, 2 ... loading platform, 3L, 3R ... support part, 4L, 4R ... drive motor, 5L, 5R ... drive Wheel, 6F, 6R: driven wheel, 7: distance measuring device, 71: laser light source, 72: collimating lens, 73: light projecting mirror, 73a: reflecting surface, 74 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ■ ... laser light receiving unit, 703 ... distance measuring unit, 704 ... arithmetic processing unit, 705 ... data communication interface, 706 ... driving unit, 707 ... direct current component cutting unit, 708 ... · Current-voltage conversion unit, 709 ... amplification unit, 710 ... comparison unit, 711 · · · · · Threshold variable unit, 712 · · · storage unit, 713 · · · derivation unit, 80 · · · housing, 801 · · · transmission unit, 81 · · · substrate, 82 · · · · · · · · · · Disturbance light detection sensor, 8 ... control unit, 85 ... storage unit, 9 ... drive unit, 10 ... power button, 15 ... automatic guided vehicle, U ... control unit, B · · · · · Battery, T · · · communication unit, S · · · · gap, R · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · , L2: incident light, AL: disturbance light, OJ: measurement object, Pa: measurement pulse, SL: threshold value, SL1: low setting value, SL2: high setting Value, D: DC component

Claims (8)

1. A light projecting unit that emits projected light that is pulse light toward the measurement object, a disturbance light detection sensor that detects the intensity of disturbance light that is different from the projection light, and reflected by the disturbance light and the measurement object Based on a comparison result of a light receiving unit that receives the projection light and converts it into an electric signal, a comparison unit that compares the level of the electric signal of the projection light with a predetermined threshold value and binarization, and the comparison unit A distance measuring device, comprising: a distance measuring unit that measures a distance to the measurement object; and a threshold variable unit that changes the threshold according to the intensity of the disturbance light.
2. The distance measuring apparatus according to claim 1, wherein the threshold variable unit increases the threshold as the intensity of the disturbance light increases.
3. The distance measurement device according to claim 1, further comprising: a direct current component cut unit that cuts a direct current component of the electric signal; and an amplification unit that amplifies the electric signal.
4. The distance measuring device according to any one of claims 1 to 3, wherein the disturbance light detection sensor is adjacent to the light receiving unit.
5. The distance measurement according to any one of claims 1 to 4, wherein the threshold value variable unit varies the threshold value when the peak value of the projection light binarized by the comparison unit is lower than a predetermined value. apparatus.
6. The distance measuring device according to any one of claims 1 to 5, further comprising a storage unit storing a table in which the intensity of the disturbance light and the threshold are associated with each other.
7. The distance measuring device according to any one of claims 1 to 5, further comprising a deriving unit that derives an approximate curve that approximates the relationship between the intensity of the disturbance light and the threshold.
8. A movable body comprising the distance measuring device according to any one of claims 1 to 7.

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