WO2019064741A1 - Distance measurement device and moving body - Google Patents

Abstract

[Solution] This distance measurement device is configured to be provided with: a light projection unit that includes a light emission unit and that performs rotary scanning using projection light; a light reception unit; a distance measurement unit that measures the distance to an object to be measured, on the basis of emission of the projection light and light reception performed by the light reception unit; and an emission control unit that controls the light emission unit, wherein, during one cycle of the rotary scanning, the emission control unit changes the output level of the projection light and the emission interval of the projection light, while keeping the average power of the projection light fixed.

Description

Distance measuring device and moving body

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

Conventionally, various distance measuring devices have been developed. For example, Patent Document 1 discloses the following laser radar.

The laser radar of Patent Document 1 includes a laser light source, an optical scanning unit, a light detector, and a distance measuring unit. The laser light source emits a laser beam. The light scanning unit scans laser light in a target area. The photodetector receives the laser beam reflected at the target area. The distance measuring unit measures the distance to the obstacle in the target area based on the signal output from the light detector.

Here, according to the emission of the laser beam by the high pulse with high emission intensity, a noise signal due to stray light in the housing is generated in the signal from the light detector. When the obstacle is at a short distance, the light reception pulse output from the light detector due to the reflected light from the obstacle appears at a position close to the noise signal. Therefore, the light reception pulse overlaps with the noise signal to generate a composite wave. Although the distance is measured based on the timing at which the composite wave exceeds the threshold voltage, this timing is earlier than the timing that should be originally detected, resulting in an error in the measurement distance.

So, in patent document 1, when radiate | emitting the low pulse with low luminous intensity, the pulse width of a low pulse is made narrower than a high pulse. Thus, even if the obstacle is at a short distance, the light reception pulse is less likely to overlap the noise signal. Therefore, since the light reception pulse exceeds the threshold voltage at the timing when the noise signals do not overlap, it is possible to suppress the decrease in accuracy of the measurement distance.

JP 2012-159330 A

However, in Patent Document 1 described above, the object is to improve the distance measurement accuracy for an object at a short distance, but the distance measurement is not performed for an object at a long distance in a specific range in the scanning range.

In view of the above situation, the present invention provides a distance measuring device capable of performing distance measurement on an object at a long distance in a specific range in a rotational scanning range.

An exemplary distance measuring device according to the present invention includes a light emitting unit including a light emitting unit and performing a rotational scan with projection light, a light receiving unit, and an object to be measured based on emission of the projection light and light reception by the light receiving unit. And a light emission control unit for controlling the light emission unit, wherein the light emission control unit is configured to set the average power of the projection light constant in one cycle of the rotational scan. Control is performed to change the light output level and the light emission interval of the projection light.

According to the exemplary distance measurement device of the present invention, it is possible to perform distance measurement on a distant object in a specific range in the rotational scanning range.

FIG. 1 is a schematic overall perspective view of an automatic guided vehicle according to an embodiment of the present invention. FIG. 2 is a schematic side view of an automated guided vehicle according to an embodiment of the present invention. FIG. 3 is a plan view of the automatic guided vehicle according to the embodiment of the present invention as viewed from above. FIG. 4 is a schematic side 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 block diagram showing the electrical configuration of the automatic guided vehicle according to the embodiment of the present invention. FIG. 7 is a waveform diagram showing an example of light emission control. FIG. 8 is a diagram showing an example of a scan range in which distance measurement is possible. FIG. 9 is a diagram showing an example of a scanning range set in accordance with the traveling direction of the automatic guided vehicle. FIG. 10 is a view showing an example of a scanning range set in accordance with the traveling direction of the automatic guided vehicle. FIG. 11 is a diagram showing an example of a far-distance scanning range which is variably set. FIG. 12 is a waveform diagram showing an example of light emission control after switching. FIG. 13 is a waveform diagram showing an example of light emission control after switching. FIG. 14 is a view showing an example of a short distance range in which a distance can be measured in a carriage traveling in a passage. FIG. 15 is a view showing an example of a short distance range and a long distance range in which a distance can be measured in a carriage traveling in a path. FIG. 16 is a diagram showing an example of setting a plurality of far-distance scanning ranges.

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 generally referred to as an AGV (Automatic Guided Vehicle).

<1. General Configuration of Unmanned Transportation Vehicle> FIG. 1 is a schematic overall perspective view of an unmanned transportation vehicle 15 according to an embodiment of the present invention. FIG. 2 is a schematic side view of an unmanned transfer vehicle 15 according to an embodiment of the present invention. FIG. 3 is a plan view of the automatic guided vehicle 15 according to the embodiment of the present invention as viewed from above. The unmanned transfer vehicle 15 travels autonomously by two-wheel drive and transports a load.

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 rear upper 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 portion 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 measurement device 7 is used for obstacle detection, map information creation, and self-position identification 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 speed reducer (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 speed reducer (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 side of the base 1A. The driven wheel 6R is fixed to the rear side 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 turned clockwise or counterclockwise to change its direction.

The base 1A accommodates the control unit U, the battery B, and the communication unit T therein. 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. Thereby, the unmanned transfer vehicle 15 can be remotely operated 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 schematic side sectional view of the distance measuring device 7. The distance measuring device 7 configured as a laser range finder includes a laser light source 71, a collimator lens 72, a light projecting mirror 73, a light receiving lens 74, a light receiving mirror 75, a wavelength filter 76, a light receiving unit 77, and A housing 78, a motor 79, a housing 80, a substrate 81, and a wire 82 are provided.

The housing 80 has a substantially cylindrical shape extending in the vertical direction in appearance, and accommodates various configurations including the laser light source 71 in the internal space. 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, for example, laser light in the infrared region downward.

The collimator lens 72 is disposed below the laser light source 71. The collimator lens 72 emits the laser light 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 emitted from the collimator lens 72, and emits the reflected laser beam as the projection light L1. Since the light projection mirror 73 is rotationally driven as described above, the projection light L1 is emitted while changing the emission direction in the range of 360 degrees around the rotation axis J.

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 projection light L1 reflected and emitted by the light projection mirror 73 passes through the transmission portion 801, passes through the gap S, and is emitted to the outside from the unmanned transfer vehicle 15. In the present embodiment, as shown in FIG. 3, the predetermined rotational scanning 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 projection light L1 passes through the transmission portion 801 at least in the range of 270 degrees around the rotation axis J. In the range in which the rear transmitting portion 801 is not disposed, the projection light L1 is blocked by the inner wall of the housing 80 or the wiring 82 or the like.

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 wavelength filter 76 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 wavelength filter 76 and is fixed to the rotating housing 78.

The projection light 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 as incident light L 2 and is incident on the light receiving lens 74. The incident light L2 transmitted through the light receiving lens 74 is incident on the light receiving mirror 75 and is reflected downward by the light receiving mirror 75. The reflected incident light L 2 passes through the wavelength filter 76 and is received by the light receiving unit 77. The wavelength filter 76 transmits light in the infrared region. The light receiving unit 77 converts the received light into an electrical signal by photoelectric conversion.

When the rotary housing 78 is rotationally driven by the motor 79, the light receiving lens 74, the light receiving mirror 75, the wavelength filter 76, and the light receiving unit 77 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 rotational scanning angle range θ (= 270 degrees) is defined as a measurement range Rs. However, the predetermined radius changes in accordance with the output level of the projection light L1. When the projection light L1 is emitted in the rotational scanning angle range θ and the projection light L1 is reflected by the measurement object located in the measurement range Rs, the reflected light is transmitted as the incident light L2 through the transmission portion 801 and the light receiving lens 74 It is incident on

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.

As shown in FIG. 5, the distance measuring device 7 includes a laser light emitting unit 701, a laser light receiving unit 702, a distance measuring unit 703, a first arithmetic processing unit 704, a data communication interface 705, and a driving unit 707. And a motor 79.

The laser light emitting unit 701 has a laser light source 71 (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. The light emitting unit 701, the light emitting mirror 73, the rotary housing 78, and the motor 79 constitute a light emitting unit. The light projector performs rotational scanning with the projection light L1.

The laser light receiving unit 702 includes a light receiving unit 77, and a comparator (not shown) that receives an electrical signal output from the light receiving unit 77. The comparator is mounted on the light receiving unit 77, compares the level of the electric signal with a predetermined threshold level, and outputs a measurement pulse which is set to the high level or the low level according to the comparison result.

The distance measurement unit 703 receives the measurement pulse output from the laser light receiving unit 702. The laser emission unit 701 emits a pulse-like laser beam using the laser emission pulse output from the first arithmetic processing unit 704 as a trigger. At this time, the projection light L1 is emitted. When the emitted projection 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 by the first 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.

The drive unit 707 rotationally controls the motor 79. The motor 79 is rotationally driven by the drive unit 707 at a predetermined rotational speed. The first arithmetic processing unit 704 outputs a laser emission pulse each time the motor 79 rotates by a predetermined unit angle. 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 projection light L1 is emitted. For example, pulsed projection light L1 is projected every 0.25 degrees. That is, eight shots are performed between two degrees.

The first arithmetic processing unit 704 determines orthogonal coordinates based on the distance measuring device 7 based on the rotational 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 location information on the system. 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 first arithmetic processing unit 704 as measurement distance data. Thus, the distance image of the measurement object OJ can be acquired by scanning with the projection light L1 in the rotational scanning 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 first arithmetic processing unit 704 corrects the measurement data according to the length of the measurement pulse to improve the distance measurement accuracy. The first arithmetic processing unit 704 uses the corrected measurement data when generating the measurement distance data.

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

<4. Electrical Configuration of Unmanned Transportation Vehicle> The electrical configuration of the distance measurement device 7 has been described as described above, but here, the electrical configuration of the unmanned transportation vehicle 15 will be described with reference to FIG. FIG. 6 is a block diagram showing the electrical configuration of the automatic guided vehicle 15.

As shown in FIG. 6, the automatic guided vehicle 15 has a distance measurement device 7, a control unit 8, a drive unit 9, and a communication unit T.

The control unit 8 is provided in the control unit U (FIG. 1). The drive unit 9 includes a motor driver (not shown), drive motors 4L and 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 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 AGV 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 measurement 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 self-location of the unmanned transfer vehicle 15 to identify its own position. Do. That is, the control unit 8 functions as a position identification unit. 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.

<5. Regarding Emission Control> Next, emission control of the projection light L1 performed in the distance measuring device 7 of the present embodiment will be described. The light emission control of the projection light L1 is performed by the first arithmetic processing unit 704 controlling the laser light emitting unit 701. That is, the first arithmetic processing unit 704 functions as a light emission control unit.

FIG. 7 is a view showing an example of light emission control of the projection light L1 according to the present embodiment. In FIG. 7, the horizontal axis represents time, and the vertical axis represents the output level of the projection light L1. As shown in FIG. 7, the projection light L1 emits light as a pulse.

In the example shown in FIG. 7, in one cycle T, a range t1 of a predetermined output level, a range t2 which is adjacent after the range t1 and whose output level is higher than the range t1, and a range t2 which is adjacent after the range t2 Even the lower range t3 of the output level is included. The output levels are the same in the range t1 and the range t3. In the range t2, the light emission interval is longer than the ranges t1 and t3. In one cycle T, the width of the light emission pulse is constant. Thereby, the average power Pa in each of the ranges t1 to t3 is the same.

In the example of FIG. 7, since the output level is doubled in the range t2 compared to the ranges t1 and t3, the light emission interval is doubled. Since the rotational speed of the rotational scan by the motor 79 is constant, in the range t2, light emission pulses are generated for each large rotation angle as compared with the ranges t1 and t3. For example, if it is assumed that light emission pulses are generated every 0.25 degrees in the ranges t1 and t3, light emission pulses are generated every 0.5 degrees in the range t2. Therefore, in the ranges t1 and t3, the angular resolution of distance measurement is high.

A scanning range corresponding to the light emission control of FIG. 7 is shown in FIG. The range t1 of FIG. 7 corresponds to the short-distance scanning range R1 shown in FIG. The range t2 of FIG. 7 corresponds to the long-distance scanning range R2 shown in FIG. The range t3 in FIG. 7 corresponds to the short-distance scanning range R3 shown in FIG. In the scanning range R2, distance measurement for an object located at a long distance is possible. That is, it is possible to measure the distance for a long distance object in a specific range in the rotational scanning range.

In the control shown in FIG. 7, in the low output level ranges t1 and t3, the first arithmetic processing unit 704 measures the distance of each emission pulse measured for each two adjacent emission pulses in time. An average value may be calculated, and measurement distance data based on the calculated average value may be output from the data communication interface 705. At this time, the first arithmetic processing unit 704 outputs measurement distance data based on the distance measured for each light emission pulse in the high output level range t2. That is, in the range t2, the average value of the distances is not calculated.

In this way, it is possible to suppress the reduction in the angular resolution of distance measurement in the far-distance range corresponding to the range t2.

<6. Regarding Setting of Scanning Range> The scanning range shown in FIG. 8 is an example, and the setting control of the scanning range in the light emission control described above can be performed, for example, as follows.

The control unit 8 in the unmanned transfer vehicle 15 transmits, for example, drive information of the drive motors 4L and 4R as movement information of the unmanned transfer vehicle 15 to the distance measuring device 7, or route information stored in the storage unit 85 as movement information. Transmit to distance measuring device 7. That is, the control unit 8 functions as a transmission unit that transmits movement information related to the movement of the unmanned transfer vehicle 15.

The first arithmetic processing unit 704 in the distance measuring device 7 raises the output level of the light emitting pulse in a predetermined scanning range including the traveling direction of the unmanned transfer vehicle 15 based on the movement information transmitted from the control unit 8. The output level is lowered in the scanning range other than the predetermined scanning range. That is, the range t1 to t3 in FIG. 7 described above is set variably.

The example illustrated in FIG. 9 illustrates a setting example of the scanning range in the case where the traveling direction D1 of the unmanned transfer vehicle 15 is the straight direction. The output level becomes high in a predetermined scanning range including the advancing direction D1, the far-distance scanning range R2 is set, and the short-distance scanning ranges R1 and R3 are set outside the predetermined scanning range.

Further, in the example shown in FIG. 10, a setting example of the scanning range in the case where the traveling direction D2 of the unmanned transfer vehicle 15 is the straight direction and the turning direction is shown. The output level becomes high in a predetermined scanning range including the traveling direction D2, the far-distance scanning range R2 is set, and the short-distance scanning ranges R1 and R3 are set outside the predetermined scanning range.

As a result, distance measurement in a far distance range including the traveling direction of the automatic guided vehicle 15 can be performed, and the state of a far distance object can be monitored. For example, when an object detected in a long distance range approaches the AGV 15, the AGV 15 can be decelerated. Thereby, collision of the unmanned carrier 15 with an object can be suppressed.

Further, the first arithmetic processing unit 704 obtains movement speed information on the movement speed of the unmanned transfer vehicle 15 from the control unit 8, thereby increasing the output level based on the movement speed information, and thus the output level in the predetermined scanning range. May be variably controlled. Specifically, the higher the moving speed, the higher the output level.

Furthermore, at this time, the first arithmetic processing unit 704 may narrow the above-described predetermined range in which the output level is increased as the moving speed is higher.

For example, in the example shown in FIG. 11, long-distance scanning ranges R2 and R21 set in a predetermined scanning range including the traveling direction D1 are shown. The scanning range R21 is set when the moving speed is faster than the scanning range R2, and since the output level becomes high, the distance of the long distance becomes long. Furthermore, at this time, the scan range R21 is set to a range narrower than the scan range R2.

By setting the scanning range R21 when the moving speed is high as described above, it is possible to measure the distance of an object at a longer distance, and it is possible to suppress the collision of the automated guided vehicle 15 with the object. Furthermore, by setting the scanning range R21 to be narrow, the average power of the projection light L1 in one cycle can be suppressed even if the output level is increased.

<7. Regarding Switching of Control> In the present embodiment, switching from the above-described light emission control to another control as described below may be performed.

FIG. 12 is a waveform diagram showing an example of light emission control after switching from the light emission control shown in the example of FIG. 7. In FIG. 12, in one cycle T, the output level of the light emission pulse is made higher in the range t12 than in the ranges t11 and t13. In the range t11 to t13, the light emission interval is constant. Therefore, the average power in each of the ranges t11 and t13 is different from the average power in the range t12. Then, in the low range t11, t13 of the output level, the output level is lower than the range t1, t3 of the low output level shown in FIG.

Therefore, in the control after switching shown in the example in FIG. 12, since the light emission interval is constant, it is possible to suppress the decrease in the angular resolution in the range t12 where the output level is high. Further, in the low output level ranges t11 and t13, the output level is made lower, so that the increase in average power in one cycle can be suppressed even if the light emission interval is constant.

For example, when the control unit 8 detects that the distance from the current position of the unmanned carrier 15 to an object such as a wall is closer than a predetermined distance based on the map information stored in the storage unit 85, the fact is By notifying the arithmetic processing unit 704, the first arithmetic processing unit 704 switches the light emission control described above. In this case, in the light emission control after switching, the output level becomes lower in the range of the low output level, and the distance in the short distance scanning range becomes shorter. However, it is the use of light emission control in a situation where there is no problem even in distance measurement in a closer range.

Further, as shown in FIG. 13, the light emission interval may be made longer than in FIG. 12 in the low output level ranges t11 and t13. That is, in the light emission control after switching, the light emission interval at a low output level may be variable.

In this way, for example, when the position of the automatic guided vehicle 15 is very close to the wall etc., the light emission interval at a low output level is increased as shown in FIG. Object's distance information can be thinned appropriately. Map information is comprised by the positional information on a predetermined space | interval. When the light emission interval is short, the measured position data (measurement distance data) becomes position data at a narrower interval than the map information, and therefore, a process of thinning out the measurement data is required when performing self-position identification. Therefore, in the case of a short distance, by increasing the light emission interval, it is possible to thin the measurement data in advance to prevent the thinning process of the data.

<8. Regarding Self-Position Identification As described above, the control unit 8 can perform self-position identification based on the comparison between the map information stored in the storage unit 85 and the measurement distance data. At this time, the light emission control shown in the example of FIG. 7 described above can be used.

For example, when the unmanned conveyance vehicle 15 moves in the long-lasting passage 50 as shown in FIG. 14, when the light emission control is always performed at a low output level in one cycle, the scanning range becomes the short range Rn. The distance is measured only for the aisle 50 located at the distance. Therefore, even if the measured distance data to be acquired is compared with the map information, the self position becomes unknown.

Then, in such a case, if the light emission control is switched to the light emission control as shown in the example of FIG. 7 described above, as shown in FIG. 15, the scan range is added to the short scan range R1, R3 and far Since the scanning range R2 of the distance is obtained, the distance can be measured not only for the passage 50 but also for the wall 51 located at the back of the passage 50. Therefore, if the measured distance data to be acquired is compared with the map information, it becomes possible to identify the self position by the detection of the wall 51 which is a characteristic object.

<9. About Multiple Range Setting of High Output Level> In the light emission control shown in the example in FIG. 7 described above, the range t2 for setting the high output level in one cycle T is single, but multiple ranges for setting the high output level are set May be

For example, as shown in FIG. 16, the distance measuring device 7 may be mounted on a car 60. In this case, the first arithmetic processing unit 704 of the distance measuring device 7 sets two ranges of high output levels in one cycle. As shown in FIG. 16, the short-distance scanning ranges R101, R102, and R103 are set according to the range of the low output level set in one cycle. Then, long-distance scanning ranges R201 and R202 are set according to the set ranges of the two high output levels.

As a result, as shown in FIG. 16, when the automobile 60 comes to an intersection, by setting the long-distance scanning ranges R201 and R202, distance measurement is performed for an object such as an automobile located on the left and right of the automobile 60. It can be carried out. Thereby, the safety of driving the automobile 60 can be enhanced.

<10. Functions and effects of the present embodiment> As described above, the distance measuring device (7) of the present embodiment includes the light emitting part (701) and the light emitting part that performs rotational scanning with the projection light (L1); A distance measuring unit (703) for measuring the distance to the measurement object based on the emission of the projection light and the light reception by the light receiving unit, and a light emission control unit (704) for controlling the light emitting unit Prepare. The light emission control unit performs control to change the output level of the projection light and the light emission interval of the projection light while keeping the average power of the projection light constant in one cycle of the rotational scanning.

According to such a configuration, it is possible to perform distance measurement on an object at a long distance within a specific range in the rotational scanning range.

Further, it further comprises a measured distance data output unit (704, 705) for outputting measured distance data based on a distance measurement result by the distance measuring unit (703), wherein the measured distance data output unit outputs the output level in the control. In the low range, the average value of the distance measurement results based on light emission units adjacent in time is taken as the measurement distance data, and in the range where the output level in the control is high, the distance measurement results for each light emission unit The measurement distance data is used.

Thereby, it is possible to suppress the decrease in the angular resolution of distance measurement in the far distance range.

Further, the light emission control unit (704) can switch from the control to a mode in which the light emission interval is fixed and the output level is variable in one cycle of the rotational scanning, and the low output in the mode The level is lower than the lower output level in the control.

Thereby, in the above mode, it is possible to suppress a decrease in angular resolution in a range where the output level is high. Further, in the above mode, since the low output level is set to the lower level, the increase in average power can be suppressed even if the light emission interval is constant. As for the short distance, the above mode can be used in a situation where there is no problem in distance measurement in the short distance range.

Further, the light emission control unit (704) makes the light emission interval at the low output level variable in the mode.

Accordingly, when the distance between the distance measuring device and the object is very short, the distance information of the object to be measured can be appropriately thinned by increasing the light emission interval of the low output level. For example, the map information is composed of position information at predetermined intervals. When the light emission interval is short, the measured position data becomes position data at an interval narrower than the map information, and therefore, a process of thinning out the measurement data is required when performing self-position identification. Therefore, in the case of a short distance, by increasing the light emission interval, it is possible to thin the measurement data in advance to prevent the thinning process of the data.

Further, in the control, the range in which the output level is high is plural. This makes it possible to perform distance measurement in a plurality of specific far distances.

Further, the mobile unit (15) of the present embodiment includes the distance measurement device (7) having any one of the above configurations, and a transmission unit (8) that transmits movement information on the movement of the mobile unit to the distance measurement apparatus. The light emission control unit (704) raises the output level of a predetermined rotational scanning range including the traveling direction of the movable body based on the movement information.

Thereby, the collision of the moving body with the object can be suppressed by enabling the distance measurement in the range of the long distance including the traveling direction of the moving body.

In addition, the light emission control unit (704) increases the output level in the range in which the output level is high as the moving speed of the moving body (15) increases. Thus, as the moving speed of the moving object is higher, distance measurement in a longer distance range is possible, and collision with the object can be suppressed.

Further, the light emission control unit (704) narrows the range in which the output level is high as the moving speed of the moving body (15) is higher. As a result, even if the output level is increased, the increase in average power can be suppressed.

In addition, the movable body (15) of the present embodiment includes the measurement distance data output unit (704, 705) for outputting measurement distance data based on the distance measurement result by the distance measurement unit (703). And a position identification unit (8) for performing self-position identification based on comparison between map information and the measurement distance data.

This makes it possible to prevent the self position from becoming unknown by detecting a characteristic object at a long distance when the moving object travels in a place where similar landscapes continue.

Moreover, it is preferable that the said moving body is a conveyance vehicle. This is because it is common for a transport vehicle to travel in a place where an obstacle exists or to travel autonomously.

<11. 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, an unmanned transport vehicle has been described as an example of the moving body. However, the present invention is not limited to this. The moving body may be applied to devices other than transport applications such as a cleaning robot and a monitoring robot.

The present invention can be used, for example, in an automatic guided vehicle for carrying a load.

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, 74: light receiving lens, 75 · · · Light receiving mirror, 76 · · · wavelength filter, 77 · · · light receiving unit, 78 · · · rotating housing, 79 · · · · · · · · · · · · · · · · · · · · · · · · · laser light emitting unit, 702 · · · laser light receiving unit, 703 ... Distance measurement unit, 704 ... First operation processing unit, 705 ... Data communication interface, 707 ... Drive unit, 80 ... Housing, 801 ... Transmission unit, 81 ... Substrate 82 82 Wiring 8 Control unit 85 Storage unit 9 Drive unit 15. Unmanned transport vehicle, U: Control unit, B: Battery, T: Communication unit, S: Gap, Rs: Measurement range, θ: Rotational scanning angle range, J: Rotational axis, L1: Projected light, L2: Incident light, OJ: Measurement object

Claims (11)

A light emitting unit including a light emitting unit for performing rotational scanning with projection light, a light receiving unit, and a distance measuring unit for measuring a distance to a measurement object based on emission of the projection light and light reception by the light receiving unit; And a light emission control unit for controlling the light emission unit, wherein the light emission control unit sets an output level of the projection light and a light emission interval of the projection light with a constant average power of the projection light in one cycle of the rotational scanning. A distance measuring device that performs control to change the The measurement distance data output unit is further provided to output measurement distance data based on the distance measurement result by the distance measurement unit, and the measurement distance data output unit is temporally adjacent in a range where the output level in the control is low. The average value of the distance measurement results based on the light emission unit to be used as the measurement distance data, and in the range where the output level in the control is high, the distance measurement result for each light emission unit is the measurement distance data. Distance measurement device according to. The light emission control unit can switch from the control to a mode in which the output level is variable with the light emission interval fixed in one cycle of the rotational scan, and the low output level in the mode is the control The distance measuring device according to claim 1, wherein the power level is lower than the low power level. The distance measurement apparatus according to claim 3, wherein the light emission control unit changes a light emission interval at the low output level in the mode. The distance measurement device according to any one of claims 1 to 4, wherein in the control, the range in which the output level is high is plural. A distance measurement apparatus according to any one of claims 1 to 5, and a transmission unit for transmitting movement information on movement of the mobile object to the distance measurement apparatus, the light emission control unit comprising A moving body, which raises the output level of a predetermined rotational scanning range including the traveling direction of the moving body based on movement information. The moving body according to claim 6, wherein the light emission control unit increases the output level in the range in which the output level is high as the moving speed of the moving body is higher. The movable body according to claim 7, wherein the light emission control unit narrows the range in which the output level is high as the moving speed of the movable body is higher. The distance measurement apparatus according to any one of claims 1 to 5, further comprising: a measurement distance data output unit that outputs measurement distance data based on a distance measurement result by the distance measurement unit; map information; and the measurement distance And a position identification unit that performs self-position identification based on collation with data. The mobile unit according to any one of claims 6 to 8, which is a carrier. The mobile unit according to claim 9, which is a carrier.

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