JPWO2019058678A1 - Distance measuring device and a moving body equipped with it - Google Patents

Abstract

The distance measuring device includes a light projecting unit that emits projected light, which is pulsed light, toward an object to be measured, a disturbance light detection sensor that detects the intensity of disturbance light different from the projected light, and the disturbance light and the measurement. A light receiving unit that receives the projected light reflected by an object and converts it into an electric signal, a comparison unit that binarizes the level of the electric signal of the projected light with a predetermined threshold, and the comparison unit. A distance measuring unit that measures the distance to the measurement object based on the comparison result, and a threshold variable unit that changes the threshold according to the intensity of the ambient light are provided.

Description

The present invention relates to a distance measuring device and a moving body including the same.

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

Then, the propagation delay time measuring means compares the received signal with the comparison value, recognizes the time when the received signal becomes equal to or more than the comparison value as the reception detection time, and propagates from the time when the irradiation means irradiates to the reception detection time. Time the delay time. The distance calculation means calculates the distance between the obstacle and the own vehicle based on the propagation delay time.

Japanese Unexamined Patent Publication No. 8-304535

However, according to the conventional vehicle distance measuring device (distance measuring device), the comparison value may be set high in advance. In this case, even if the received signal due to the actual disturbance is small at the time of distance measurement, the comparison value is maintained high, and the received signal due to the reflected wave at the obstacle (measurement object) of the electromagnetic wave is evaluated relatively small. There is a risk. Further, in the above-mentioned conventional vehicle distance measuring device, when the comparison value is set in consideration of ambient light such as sunlight, the comparison value may be set high in advance. Therefore, there is a problem that the distance measurement of the vehicle distance measuring device becomes inaccurate and the reliability of the vehicle distance measuring device is lowered.

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

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

An exemplary mobile body of the present invention includes a distance measuring device having the above configuration.

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

FIG. 1 is a perspective view of an automatic guided vehicle including a distance measuring device according to an embodiment of the present invention. FIG. 2 is a side view of an automatic guided vehicle including a distance measuring device according to an embodiment of the present invention. FIG. 3 is a plan view of an automatic guided vehicle provided with a distance measuring device according to an embodiment of the present invention as viewed from above. FIG. 4 is a side sectional view of the distance measuring device according to the embodiment of the present invention. FIG. 5 is a block diagram showing an electrical configuration of a distance measuring device according to an 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 when the electric signal of the light received by the light receiving unit is amplified without cutting the DC component in the presence of ambient light. FIG. 8 is a block diagram showing an electrical configuration of an automatic guided vehicle according to an embodiment of the present invention. FIG. 9 is a block diagram showing an electrical configuration of a distance measuring device according to a modified example of the embodiment of the present invention.

An exemplary embodiment 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. Further, as a moving body equipped with a distance measuring device, an automatic guided vehicle, which is used for transporting luggage, will be described as an example. The automatic guided vehicle is also generally called an AGV (Automated Guided Vehicle).

<1. Overall configuration of automatic guided vehicle> FIG. 1 is a perspective view of an automatic guided vehicle 15 including a distance measuring device 7 according to an embodiment of the present invention. FIG. 2 is a side view of an automatic guided vehicle 15 including a distance measuring device 7 according to an embodiment of the present invention. FIG. 3 is a plan view of the automatic guided vehicle 15 including the distance measuring device 7 according to the embodiment of the present invention as viewed from above. The automatic guided vehicle 15 autonomously travels by two-wheel drive and carries luggage. In particular, the automatic guided vehicle 15 can rotate on the spot.

The automatic guided 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, trailing wheels 6F and 6R, and a distance measuring device 7. ..

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

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

The support portion 3L is fixed to the left side of the base portion 1A and supports the drive motor 4L. The drive motor 4L is configured by an AC servomotor as an example. The drive motor 4L has a built-in speed reducer (not shown). The drive wheels 5L are fixed to the rotating shaft of the drive motor 4L.

The support portion 3R is fixed to the right side of the base portion 1A and supports the drive motor 4R. The drive motor 4R is configured by an AC servomotor as an example. The drive motor 4R has a built-in speed reducer (not shown). The drive wheels 5R are fixed to the rotating shaft of the drive motor 4R.

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

The automatic guided vehicle 15 can be moved forward and backward by rotationally driving the drive wheels 5L and 5R by the drive motors 4L and 4R. Further, by controlling so as to provide a difference in the rotation speeds of the drive wheels 5L and 5R, the automatic guided vehicle 15 can be rotated clockwise or counterclockwise to change the direction.

A control unit U, a battery B, and a communication unit T are housed inside the base 1A. The control unit U is connected to a distance measuring device 7, drive motors 4L, 4R, 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 controls the drive of the drive motors 4L and 4R. The communication unit T communicates with an external tablet terminal (not shown) and conforms to, for example, Bluetooth (registered trademark). Therefore, the automatic guided vehicle 15 can be remotely controlled by the tablet terminal. The battery B is composed of, for example, a lithium ion battery, and supplies electric power to each unit such as a distance measuring device 7, a control unit U, and a communication unit T.

<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 housing 80 extending in the vertical direction in terms of appearance. Inside the housing 80, a laser light source 71, a collimating lens 72, a floodlight mirror 73, a light receiving lens 74, a light receiving mirror 75, a bandpass filter 76, a light receiving portion 77, a rotating housing 78, and the like. The motor 79, the substrate 81, the wiring 82, and the ambient light detection sensor 83 are housed.

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 laser light L1 (projected light) of pulsed light in an infrared region (about 905 nm) downward, for example. In the present embodiment, the laser beam L1 emitted from the laser light source 71 has a rectangular shape in a plane orthogonal to the optical axis.

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

A floodlight mirror 73 is arranged below the collimating lens 72. The floodlight mirror 73 is fixed to the rotating housing 78. The rotary housing 78 is fixed to the shaft 79A of the motor 79, and is rotationally driven around the rotary shaft J by the motor 79. Along with the rotation of the rotating housing 78, the floodlight mirror 73 is also rotationally driven around the rotation axis J. The projection mirror 73 reflects the laser light L1 transmitted through the collimating lens 72 on the reflecting surface 73a, and projects the reflected laser light L1 to the outside of the housing 80. Since the projection mirror 73 is rotationally driven as described above, the laser beam L1 is emitted while changing the emission direction within a 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 shape of the laser beam L1 emitted to the outside of the automatic guided vehicle 15 as the rotating housing 78 rotates rotates from one of the vertically elongated state and the horizontally elongated state to the other.

The laser light source 71 and the projection mirror 73 constitute a projection unit that emits laser light L1, which is pulsed light, toward an object to be measured.

The housing 80 has a transmission portion 801 in the middle in the vertical direction. The transmissive portion 801 is made of a translucent resin or the like.

The laser beam L1 reflected by the reflecting surface 73a of the projection mirror 73 passes through the transmitting portion 801 and passes through the gap S (see FIG. 2) and is emitted to the outside from the automatic guided vehicle 15. In the present embodiment, the predetermined scanning rotation angle range θ is set to 270 degrees around the rotation axis J as an example, as shown in FIG. More specifically, the range of 270 degrees includes 180 degrees forward and 45 degrees rearward and left and right respectively. The laser beam L1 transmits through the transmission portion 801 at least within a range of 270 degrees around the rotation axis J. In the range where the rear transmitting portion 801 is not arranged, the laser beam L1 is blocked by the inner wall of the housing 80, the wiring 82, or the like.

The light receiving mirror 75 is fixed to the rotating housing 78 at a position below the floodlight mirror 73. The light receiving lens 74 is fixed to the circumferential side surface of the rotating housing 78. The bandpass filter 76 has a dielectric multilayer film, is located below the light receiving mirror 75, and is fixed to the rotating housing 78. The light receiving unit 77 is located below the bandpass 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 passes through the gap S and the transmitting portion 801 in order as the incident light L2 and is incident on the light receiving lens 74. That is, the incident light L2 is a part of the laser light L1 reflected by the object to be measured. 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 L2 reflected by the light receiving mirror 75 passes through the bandpass filter 76 and is received by the light receiving unit 77. At this time, the bandpass filter 76 transmits only the light in the wavelength band of the incident light L2. In this embodiment, the bandpass filter 76 transmits only light in the infrared region.

The light receiving unit 77 converts the received incident light L2 and the disturbance light AL into an electric signal by photoelectric conversion. Specifically, the light receiving unit 77 converts the intensity of the received incident light 2 and the ambient 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 ambient light AL is, for example, light from the sun SN (sunlight), or illumination light in a room or the like where the automatic guided vehicle 15 moves. Sunlight and illumination light are continuous light. Here, continuous light means light whose output is substantially constant with respect to time, and pulsed light means light whose output peaks repeatedly appear in a predetermined cycle.

The position of the ambient light detection sensor 83 is not limited to the position adjacent to the light receiving unit 77, and may be any position as long as it can detect the intensity of the ambient light. Further, the disturbance light detection sensor 83 only needs to be able 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 rotating housing 78 is rotationally driven by the motor 79, the light receiving lens 74, the light receiving mirror 75, the bandpass filter 76, the light receiving unit 77, and the ambient light detection sensor 83 are rotationally driven together with the light projecting mirror 73.

As shown in FIG. 3, the range formed by rotating around the rotation axis J with a predetermined radius in the scanning rotation angle range θ (= 270 degrees) is defined as the measurement range Rs. When the laser light L1 is emitted in the scanning rotation angle range θ and the laser light L1 is reflected by the measurement object located within the measurement range Rs, the reflected laser light L1 is transmitted through the transmission portion 801 as the incident light L2. Then it 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 rotation speed. For example, the rotary housing 78 is rotationally driven at about 3000 rpm. The wiring 82 is routed along the vertical direction to the rear inner wall of the housing 80.

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

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

The laser light emitting unit 701 includes 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 DC component cut section 707 is composed of, for example, a capacitor, and cuts the DC component (DC component) of the electric signal (current) generated by the photoelectric conversion of the light receiving section 77. The current-voltage conversion unit 708 has, for example, a transimpedance amplifier, and converts the current generated by the photoelectric conversion of the light receiving unit 77 into a voltage.

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

The distance measurement unit 703 is input with the measurement pulse output from the comparison unit 710. The laser light emitting unit 701 emits the laser light L1 triggered by the laser light emitting pulse output from the arithmetic processing unit 704. 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 measuring unit 703.

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

The drive unit 706 controls the motor 79 to rotate. The motor 79 is rotationally driven at a predetermined rotational speed by the drive unit 706. 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 1 degree. As a result, each time the rotating housing 78 and the floodlight mirror 73 rotate by a predetermined unit angle, the laser light emitting unit 701 emits light and the laser light L1 is emitted.

The arithmetic processing unit 704 is on the Cartesian coordinate system based on the distance measuring device 7 based on the rotation angle position of the motor 79 at the timing when the laser emission pulse is output and the measurement data obtained corresponding to the laser emission pulse. Generate the position information of. That is, the position of the measurement target OJ is acquired based on the rotation angle position of the projection mirror 73 and the measured distance. The acquired position information is output from the arithmetic processing unit 704 as measurement distance data. In this way, the distance image of the measurement target 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 changes depending on the reflectance of light at the object to be measured OJ. For example, when the object to be measured OJ is a black object and the reflectance of light decreases, the amount of received light decreases and the rise of the measurement pulse becomes slow. Then, the distance measurement unit 703 will measure the distance longer. In this way, depending on the reflectance of light at the object to be measured OJ, the measured distance may change even if the distance is actually the same. Here, as the amount of received light decreases, the length of the measurement pulse becomes shorter. Therefore, the arithmetic processing unit 704 improves the measurement accuracy of the distance by correcting the measurement data according to the length of the measurement pulse. The arithmetic processing unit 704 uses the corrected measurement data when generating the measurement distance data.

The measurement distance data output from the arithmetic processing unit 704 is transmitted to the automatic guided vehicle 15 side shown in FIG. 6 described later via the data communication interface 705.

Further, the arithmetic processing unit 704 has a threshold value variable unit 711. The threshold value variable unit 711 changes the threshold value SL according to the intensity of the ambient light AL.

The storage unit 712 stores a table in which the intensity of the ambient light AL and the threshold value SL are associated with each other. For example, in the table, the higher the intensity of the ambient light AL, the higher the threshold SL.

<4. Operation of distance measuring device> In the distance measuring device 7 having the above configuration, when the laser light L1 is emitted from the laser light source 71 (see FIG. 4), the laser light L1 is transmitted through the collimating lens 72 and becomes parallel light. It is reflected by the reflecting surface 73a of the mirror 73. The laser beam L1 reflected by the reflecting 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 bandpass filter 76, and is incident on the light receiving unit 77. Further, the ambient light AL also passes through the light receiving lens 74, is reflected by the light receiving mirror 75, passes through the bandpass filter 76, and is incident on the light receiving unit 77. At this time, a part of the disturbance light AL reflected by the light receiving mirror 75 is incident on the disturbance light detection sensor 83. As a result, the intensity of the ambient light AL is detected.

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

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

FIG. 6 is a waveform diagram showing an electric signal (voltage) amplified by the amplification unit 709. The vertical axis shows the amplitude (unit: mV), and the horizontal axis shows the 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 value SL (low set value SL1) when the intensity of the ambient light AL is sufficiently small is set to about 50 mV. That is, the threshold SL when the ambient 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 the DC component of the electric signal (current) is cut, the amplitude of the electric signal due to the ambient light is about 180 mV on average. Therefore, when the comparison unit 710 compares the level of the electric signal of the incident light L2 with the low set value SL1, it is determined that not only the incident light L2 but also the disturbance light AL is at a high level. Therefore, accurate binarization becomes impossible, and the distance measurement by the distance measuring device 7 becomes inaccurate.

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

At this time, since the distance measuring device 7 includes a storage unit 712 (see FIG. 5) that stores a table in which the intensity of the ambient light AL and the threshold value SL are associated with each other, the threshold value variable unit 711 can easily change the threshold value SL. Can be done.

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

When the intensity of the disturbance light AL is sufficiently smaller than that of the incident light L2, only the DC component D may be cut by the DC component cut unit 707, and the threshold SL may not be changed by the threshold variable unit 711. ..

<5. Electrical configuration of the automatic guided vehicle> As described above, the electrical configuration of the distance measuring device 7 side has been described, but here, the electrical configuration of the automatic guided vehicle 15 side will be described with reference to FIG. FIG. 8 is a block diagram showing an electrical configuration of the automatic guided vehicle 15.

The automatic guided 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. A distance measuring device 7, a driving unit 9, a communication unit T, and a 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 includes 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 rotation speed and rotation direction of the drive wheels 5L and 5R.

The control unit 8 communicates with the tablet terminal (not shown) via the communication unit T. For example, the control unit 8 can receive an operation signal according 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 power to activate the automatic guided vehicle 15.

The control unit 8 is input with the measurement distance data output from the distance measuring device 7. The control unit 8 can create map information based on the measurement distance data. The map information is information generated for self-position identification that identifies the self-position of the automatic guided vehicle 15, and is generated as position information of a stationary object at a place where the automatic guided vehicle 15 travels. For example, when the place where the automatic guided vehicle 15 travels is a warehouse, the stationary objects are the walls of the warehouse, the shelves arranged in the warehouse, and the like.

The map information is generated when, for example, a tablet terminal manually operates the automatic guided vehicle 15. In this case, the operation signal corresponding to the operation of the tablet terminal, for example, the joystick is transmitted to the control unit 8 via the communication unit T, so that the control unit 8 issues a command to the drive unit 9 in response to the operation signal and is unmanned. The traveling vehicle 15 is controlled to travel. At this time, the control unit 8 specifies the position of the measurement target in the place where the automatic guided vehicle 15 travels as map information based on the measurement distance data input from the distance measuring device 7 and the position of the automatic guided vehicle 15. .. The position of the automatic guided vehicle 15 is specified based on the drive information of the drive unit 9.

The map information generated as described above is stored in the storage unit 85 of the control unit 8. The control unit 8 performs self-position identification that identifies the self-position of the automatic guided vehicle 15 by comparing the measurement distance data input from the distance measuring device 7 with the map information stored in advance in the storage unit 85. Do. By performing self-position identification, the control unit 8 can autonomously control the traveling of the automatic guided vehicle 15 along a predetermined route.

<6. Operation of automatic guided vehicle> Next, the operation of the automatic guided vehicle 15 and the distance measuring device 7 will be described. When the power button 10 is operated, the control unit 8 controls to supply the electric power from the battery B to each unit except the distance measuring device 7 shown in FIG. 5, and activates the automatic guided vehicle 15. As a result, the automatic guided vehicle 15 starts running. At the same time, the control unit 8 controls to supply the electric power from the battery B to the distance measuring device 7, and activates the distance measuring device 7.

At the time of creating the map information, as described above, the control unit 8 issues a command to the drive unit 9 in response to a manual operation on the tablet terminal, for example, to control the traveling of the automatic guided vehicle 15. When a manual operation for moving straight is performed, the control unit 8 commands the drive unit 9 to move the automatic guided vehicle 15 straight at a predetermined speed and a predetermined direction (forward or reverse). Further, when a manual operation for rotating is performed, the control unit 8 rotates the automatic guided vehicle 15 in a predetermined rotation speed, a predetermined rotation angle, and a predetermined rotation direction (clockwise or counterclockwise). Give a command to.

Further, when the automatic guided vehicle 15 travels autonomously while identifying its own position based on the created map information, the control unit 8 autonomously issues a command to the drive unit 9, so that the automatic guided vehicle 15 Is moved straight or rotated in the same manner as above.

In the distance measuring device 7, the arithmetic processing unit 704 starts to output the measured distance data to the automatic guided vehicle 15 via the data communication interface 705. At the time of creating the map information, the control unit 8 creates the 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 identifies the position of the automatic guided vehicle 15 based on the comparison between the measured distance data acquired from the distance measuring device 7 and the existing map information.

<7. Modification example of this embodiment> FIG. 9 is a block diagram showing an electrical configuration of a distance measuring device 7 according to a modification of this embodiment. The distance measuring device 7 may have a lead-out unit 713 instead of the storage unit 712. The derivation unit 713 is connected to the arithmetic processing unit 704 and derives an approximate curve that approximates the relationship between the intensity of the ambient 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 the trouble of creating a table in which the intensity of the disturbance light AL and the threshold value SL are associated with each other can be saved. In addition, it is possible to reduce an increase in the capacity of the storage unit or the like for holding the table.

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

<8. Action and effect of the present embodiment> According to the distance measuring device 7 of the present embodiment, the light projecting unit that emits the laser beam L1 (projected light) which is pulsed light toward the measurement object OJ is different from the laser beam L1. The disturbance light detection sensor 83 that detects the intensity of the disturbance light AL, the light receiving unit 77 that receives the laser light L1 reflected by the disturbance light AL and the measurement object OJ and converts it into an electric signal, and the electric signal of the incident light L2. Comparison unit 710 that binarizes the level with a predetermined threshold SL, distance measurement unit 703 that measures the distance to the measurement target OJ based on the comparison result of comparison unit 710, and the intensity of ambient light AL. A threshold variable unit 711 that changes the threshold SL accordingly is provided.

As a result, even when the 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 SL is changed according to the intensity of the disturbance light AL, so that the noise due to the disturbance light AL is generated. The impact can be reduced. Further, when the intensity of the disturbance light AL is low, the threshold SL is not set high, so that there is no possibility that the electric signal of the incident light L2 is evaluated relatively low. Therefore, the distance measuring device 7 can accurately measure the distance to the object to be measured 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 ambient light AL increases. As a result, it is possible to reduce the influence of sunlight or illumination light in the distance measurement of the distance measuring device 7.

The distance measuring device 7 includes a DC component cutting unit 707 that cuts a DC component (DC component) of an 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 the noise of the ambient light AL can be further removed.

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

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

The distance measuring device 7 includes a storage unit 712 that stores a table in which the intensity of the ambient light AL and the threshold value SL are associated with each other. As a result, the distance measuring device 7 can easily change the threshold SL.

The distance measuring device 7 may include a derivation unit 713 that derives an approximate curve that approximates the relationship between the intensity of the ambient light AL and the threshold value SL. As a result, the distance measuring device 7 can easily change the threshold SL. Further, the threshold value SL corresponding to the intensity of the disturbance light AL can be easily derived by interpolation, and the trouble of creating a table in which the intensity of the disturbance light AL and the threshold value SL are associated with each other can be saved. In addition, it is possible to reduce an increase in the capacity of the storage unit or the like for holding the table.

The automatic guided vehicle 15 (moving body) includes a distance measuring device 7. Thereby, the automatic guided 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 gist of the present invention.

For example, in the above embodiment, the automatic guided vehicle 15 has been described as an example of the moving body, but the present invention is not limited to this, and the moving body may be applied to a device other than the transportation purpose such as a cleaning robot and a monitoring robot. .. Further, the moving body may be composed of a passenger vehicle. In this case, the distance measuring device 7 may be mounted on the lower part of the front surface of the passenger vehicle, and the distance measuring device 7 may measure the distance to an obstacle or the like in front of the passenger vehicle.

Further, the bandpass filter 76 may be omitted from the present embodiment. As a result, it is possible to suppress an increase in the pulse width of the electric signal corresponding to the incident light L2, and the distance measuring device 7 can measure the distance more accurately.

The present invention can be used, for example, in a distance measuring device and a moving body equipped with the distance measuring device.

1 ... Body, 1A ... Base, 1B ... Base, 2 ... Loading platform, 3L, 3R ... Support, 4L, 4R ... Drive motor, 5L, 5R ... Drive Wheel, 6F, 6R ... Driven wheel, 7 ... Distance measuring device, 71 ... Laser light source, 72 ... Collimating lens, 73 ... Floodlight mirror, 73a ... Reflective surface, 74. .. Light receiving lens, 75 ... Light receiving mirror, 76 ... Light receiving part, 77 ... Light receiving part, 78 ... Rotating housing, 79 ... Motor, 701 ... Laser emitting part, 702 ... laser light receiving unit, 703 ... distance measuring unit, 704 ... arithmetic processing unit, 705 ... data communication interface, 706 ... driving unit, 707 ... DC 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 ... Board, 82 ... Wiring, 83 ... Ambient light detection sensor, 8 ... Control unit, 85 ... Storage unit, 9 ... Drive unit, 10 ...・ ・ Power button, 15 ・ ・ ・ Unmanned carrier, U ・ ・ ・ Control unit, B ・ ・ ・ Battery, T ・ ・ ・ Communication unit, S ・ ・ ・ Gap, Rs ・ ・ ・ Measurement range, θ ・ ・ ・Scanning rotation angle range, J ... rotation axis, L1 ... laser light (projected light), L2 ... incident light, AL ... disturbance light, OJ ... measurement object, Pa ... measurement Pulse, SL ... threshold, SL1 ... low setting value, SL2 ... high setting value, D ... DC component

Claims (8)

A light projecting unit that emits projected light, which is pulsed light, toward an object to be measured, an ambient light detection sensor that detects the intensity of ambient light different from the projected light, and reflected by the ambient light and the object to be measured. Based on the comparison results of the light receiving unit that receives the projected light and converts it into an electric signal, the comparison unit that binarizes the level of the electric signal of the projected light with a predetermined threshold value, and the comparison unit. A distance measuring device including a distance measuring unit that measures the distance to the measurement object and a threshold variable unit that changes the threshold according to the intensity of the ambient light. The distance measuring device according to claim 1, wherein the threshold value variable unit raises the threshold value as the intensity of the ambient light increases. The distance measuring device according to claim 1 or 2, further comprising a DC component cutting unit that cuts a DC component of the electric signal and an amplification unit that amplifies the electric signal. 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. The distance measurement according to any one of claims 1 to 4, wherein when the peak value of the projected light binarized by the comparison unit is lower than a predetermined value, the threshold value variable unit changes the threshold value. apparatus. The distance measuring device according to any one of claims 1 to 5, further comprising a storage unit that stores a table in which the intensity of the disturbance light and the threshold value are associated with each other. The distance measuring device according to any one of claims 1 to 5, further comprising a derivation unit for deriving an approximate curve that approximates the relationship between the intensity of the disturbance light and the threshold value. A mobile body including the distance measuring device according to any one of claims 1 to 7.

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