WO2020039916A1

WO2020039916A1 - Distance measuring device, and mobile body

Info

Publication number: WO2020039916A1
Application number: PCT/JP2019/030986
Authority: WO
Inventors: 智浩江川; 和穂江川; 佐伯　哲夫; 岡本　修治; 石丸　裕; 裕多堀; 凡乃小川; 健吾井上
Original assignee: 日本電産株式会社
Priority date: 2018-08-24
Filing date: 2019-08-06
Publication date: 2020-02-27

Abstract

This distance measuring device comprises: a plurality of distance measuring units; a measuring unit; a scanning control unit; and a determination unit. The distance measuring units have a light radiating part for radiating a laser beam to outside, a light receiving part for receiving reflected light of the laser beam, and a scanning mechanism for scanning the laser beam in a rotational direction. The scanning control unit controls the driving of the scanning mechanism of each of the distance measuring units, and causes the laser beams of the respective distance measuring units to each be radiated in different directions. The measuring unit calculates a relative position of an external object on the basis of the radiation timings and the radiation directions of the laser beams, and the light receiving results of the light receiving parts. The determination unit determines whether the object is actually present at the relative position on the basis of results from comparing the relative positions calculated by the respective distance measuring units.

Description

Distance measuring device, moving body

The present disclosure relates to a distance measuring device and a moving object.

2. Description of the Related Art In recent years, mobile objects such as unmanned transport vehicles that transport goods have been introduced into factories and warehouses. The moving object is equipped with a distance measuring device that detects surrounding objects and identifies its own position.

As a prior art related to the present disclosure, Japanese Patent Laid-Open Publication No. 2007-2057775 teaches a photoelectric sensor in which light emitted from a light emitting element and reflected by a work is received by a photodiode. . The photoelectric sensor captures a light receiving signal at a timing synchronized with a light emitting timing of the light emitting element. Thus, when a plurality of photoelectric sensors are used side by side, the effect of light emitted from adjacent photoelectric sensors and entering as interference light is eliminated.

Japanese Unexamined Patent Publication: JP-A-2007-2057775

Here, when a plurality of moving objects as described above are present in the same place, the distance measuring device receives laser light emitted from another moving object, or receives laser light emitted from another moving object. It may receive reflected light. In such a case, the distance measuring device for the moving object may erroneously detect a non-existent object and its position.

An object of the present disclosure is to provide a distance measuring device and a moving object that can prevent erroneous detection of a non-existent object and its position.

An exemplary distance measurement device of the present disclosure includes a plurality of distance measurement units, a measurement unit, a scan control unit, and a determination unit. The distance measuring unit is a light irradiating unit that irradiates a laser beam to the outside of the distance measuring unit, a light receiving unit that receives reflected light of the laser beam, and scans the laser beam in a rotational direction about a rotation axis. Scanning mechanism. The scanning control unit controls the driving of the scanning mechanism of each of the distance measurement units, and irradiates the laser light emitted from the light irradiation unit of each of the distance measurement units in different directions. The measurement unit calculates a relative position of an object located outside the distance measurement unit with respect to a predetermined reference position based on the irradiation timing of the laser beam, the irradiation direction, and a light reception result of the light receiving unit. . The determination unit compares each of the relative positions calculated for each of the distance measurement units, and determines whether or not the object actually exists at the relative position based on a result of the comparison.

An exemplary moving object of the present disclosure is a moving object that travels on a road surface and includes the above-described distance measuring device.

According to the exemplary distance measurement device and the moving object of the present disclosure, it is possible to prevent a non-existent object and its position from being erroneously detected.

FIG. 1 is a perspective view illustrating a configuration example of the automatic guided vehicle according to the embodiment. FIG. 2 is a top view of the automatic guided vehicle according to the embodiment. FIG. 3A is a cross-sectional view illustrating a configuration example of a distance measuring unit of the distance measuring unit according to the embodiment. FIG. 3B is a block diagram illustrating a configuration example of a distance measurement unit and a measurement control unit of the distance measurement unit according to the embodiment. FIG. 4 is a diagram illustrating the difference in the irradiation direction of the laser light emitted from each of the two distance measurement units. FIG. 5 is a block diagram illustrating a configuration example of a control unit. FIG. 6 is a perspective view illustrating a case where a plurality of automatic guided vehicles are present. FIG. 7 is a flowchart illustrating a method for adjusting the irradiation direction of laser light in the embodiment. FIG. 8 is a top view illustrating another example of the arrangement of the distance measurement unit of the distance measurement unit. FIG. 9 is a top view of an automatic guided vehicle according to a modification. FIG. 10 is a cross-sectional view illustrating a configuration example of a distance measurement unit of a distance measurement unit according to a modification. FIG. 11 is a flowchart for explaining a method of adjusting the irradiation direction of laser light in the modification.

Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings.

In the present specification, in the vertical direction D1, a symbol “D1d” is given below vertically, and a symbol “D1t” is given above it vertically. In each component, the end in the vertically lower direction D1d is referred to as “lower end”, and the position of the lower end in the vertical direction D1 is referred to as “lower end”. Further, an end in the vertically upper direction D1t is referred to as an “upper end”, and a position of the upper end in the vertical direction D1 is referred to as an “upper end”. Further, in the end faces of the respective components, a surface facing vertically downward D1d is referred to as “lower surface”, and a surface facing vertically upward D1t is referred to as “upper surface”.

In the horizontal direction, the direction perpendicular to the vertically lower portion D1d and in which the unmanned transport vehicle 100 described later advances is referred to as “front D2f”, and the direction opposite to the front D2f is referred to as “rear D2b”. In each component, the end of the front D2f is referred to as “front end”, and the position of the front end of the front D2f is referred to as “front end”. Further, the end at the rear D2b is referred to as a "rear end", and the position of the rear end at the rear D2b is referred to as a "rear end". In addition, a surface facing the front D2f is referred to as a “front surface”, and a surface facing the rear D2b is referred to as a “back surface”.

In the horizontal direction, a direction that is perpendicular to both the vertically lower part D1d and the front part D2f is referred to as a “lateral direction D3”. In the left-right direction D3, a direction from a driving wheel 105R described later to a driving wheel 105L described later is referred to as “left D3L”, and a direction from the driving wheel 105L to the driving wheel 105R is referred to as “right D3R”. In each component, an end in the left side D3L is called a "left end", and a position of the left end in the left-right direction D3 is called a "left end". Further, an end in the right D3R is called a “right end”, and a position of the right end in the left / right direction D3 is called a “right end”. Further, in the side surfaces of the respective components, a surface facing the left D3L is called a "left surface", and a surface facing the right D3R is called a "right surface".

In the following, a plurality of distance measurement units including a first distance measurement unit 21 and a second distance measurement unit 22, which will be described later, are collectively referred to as a distance measurement unit 2. In addition, a laser beam emitted from each distance measuring unit 2 is generically referred to as a laser beam La. The generic name of the reflected light of the laser light La is referred to as reflected light Lb. The scanning range Rs1 of the laser beam L1a emitted from the first distance measurement unit 21 and the scanning range Rs2 of the laser beam L2a emitted from the second distance measurement unit 22 are collectively referred to as a scanning range Rs.

In the distance measurement unit 2, a direction parallel to the rotation axis J extending in the up-down direction is referred to as an “axial direction”. Among the axial directions, the direction from the light receiving element 324 described later to the LD 311 described later is referred to as “axially upper”, and the direction from the LD 311 to the light receiving element 324 is referred to as “axially lower”. The axial direction is parallel to the vertical direction D1 in the present embodiment, but is not limited to the example of the present embodiment, and may be a direction that intersects the vertical direction D1. The direction perpendicular to the rotation axis J is referred to as “radial direction”. Of the radial directions, the direction toward the rotation axis J is referred to as “radially inward”, and the direction away from the rotation axis J is referred to as “radially outward”. In addition, a circumferential direction around the rotation axis J is referred to as a “rotation direction”. In each component of the distance measuring unit 2, the lower end is referred to as “axial lower end”, and the position of the lower end is referred to as “axial lower end”. Further, the upper end is referred to as “axial upper end”, and the position of the upper end is referred to as “axial upper end”. Further, among the end faces of the respective components in the distance measuring unit 2, a face facing downward is referred to as a "lower face", and a face facing upward is referred to as an "upper face".

It should be noted that the names of the directions, ends, positions, surfaces, and the like described above do not indicate the positional relationship, the directions, and the like when incorporated in actual equipment.

<1. Embodiment> <1-1. Automatic guided vehicle> FIG. 1 is a perspective view showing a configuration example of an automatic guided vehicle 100 according to the embodiment. FIG. 2 is a top view of the automatic guided vehicle 100 according to the embodiment. FIG. 2 is a view of the automatic guided vehicle 100 as viewed from vertically above D1t. Since FIG. 2 illustrates the vicinity of the automatic guided vehicle 100, a part of the scanning ranges Rs1 and Rs2 of each distance measuring unit 2 is illustrated.

The automatic guided vehicle 100 is an example of a moving object that travels on a road surface G, and is generally called an AGV (Automatic Guided Vehicle). In the present embodiment, the automatic guided vehicle 100 autonomously travels on the road surface G by two-wheel drive and transports a load. However, the moving object exemplified by the automatic guided vehicle 100 is not limited to this example, and may be used for purposes other than the conveyance of luggage.

As shown in FIGS. 1 and 2, the automatic guided vehicle 100 includes a plurality of distance measurement units 2 including a first distance measurement unit 21 and a second distance measurement unit 22. The number of the distance measurement units 2 is two in the present embodiment, but is not limited to this example, and may be three or more. Each distance measuring unit 2 has a common configuration. The configuration of the distance measuring unit 2 will be described later.

As shown in FIGS. 1 and 2, the automatic guided vehicle 100 includes a vehicle body 101, a carrier 102,

support portions

103L and 103R, drive

motors

104L and 104R, drive

wheels

105L and 105R, and driven wheels 106F. , 106R, a battery 107, a communication unit 108, and a control unit 109.

The vehicle body 101 houses a battery 107, a communication unit 108, a control unit 109, and the like. A plate-shaped carrier 102 is fixed to the upper surface of the vehicle body 101. Luggage can be placed on the upper surface of the loading platform 102.

The

support portions

103L and 103R are fixed to the left end of the vehicle body 101, and support the

drive motors

104L and 104R. As the

drive motors

104L and 104R, for example, AC servomotors are used. Each of the

drive motors

104L and 104R has a built-in speed reducer (not shown). The

drive wheels

105L and 105R are attached to shafts (not shown) of the

drive motors

104L and 104R, respectively, and contact the road surface G. The

drive wheels

105L and 105R are rotatable together with the shafts by the drive of the

drive motors

104L and 104R.

The driven wheel 106F is rotatably attached to the front end of the vehicle body 101. The driven wheel 106R is rotatably mounted at the rear end of the vehicle body 101. The driven

wheels

106F and 106R come into contact with the road surface G and rotate passively according to the rotation of the

drive wheels

105L and 105R.

By driving and driving the

drive wheels

105L and 105R by the

drive motors

104L and 104R, the automatic guided vehicle 100 can be moved forward and backward on the road surface G. In addition, by controlling the rotational speeds of the

drive wheels

105L and 105R to provide a difference, the automatic guided vehicle 100 can be rotated clockwise or counterclockwise to change the direction.

The battery 107 is a power source of the automatic guided vehicle 100, and supplies power to, for example, the plurality of distance measurement units 2, the communication unit 108, the control unit 109, and the like. As the battery 107, for example, a lithium ion battery is used.

The communication unit 108 performs communication with a tablet terminal (not shown) outside the automatic guided vehicle 100, for example, in compliance with Bluetooth (registered trademark). Thus, the automatic guided vehicle 100 can be remotely controlled by an external information device such as a tablet terminal.

The control unit 109 is connected to the

drive motors

104L and 104R, the communication unit 108, and the like. The control unit 109 controls the drive of the

drive motors

104L and 104R. The control unit 109 is further connected to the distance measurement unit 2 and receives various signals from the distance measurement unit 2 to perform various controls. A more detailed configuration of the control unit 109 will be described later.

<1-1-1. Distance measurement unit>
Next, the distance measuring unit 2 will be described. The distance measurement unit 2 is a so-called LRF (Laser Range Finder), and detects an object OJ located outside the automatic guided vehicle 100. As shown in FIGS. 3A and 3B, the distance measurement unit 2 includes a distance measurement unit 3A and a measurement control unit 3B that controls the distance measurement unit 3A. FIG. 3A is a cross-sectional view illustrating a configuration example of a distance measuring unit 3A of the distance measuring unit 2 according to the embodiment. FIG. 3B is a block diagram illustrating a configuration example of the distance measurement unit 3A and the measurement control unit 3B of the distance measurement unit 2 according to the embodiment. FIG. 3A shows a cross-sectional structure when the distance measurement unit 3A is virtually cut along a plane including the rotation axis J.

<1-1-1-1. Distance measuring unit> The distance measuring unit 3A includes a housing 30, a light irradiation unit 31, a light receiving unit 32, a rotating housing 33, and a motor 34, as shown in FIG. 3A.

The housing 30 has a hollow cylindrical shape extending in the axial direction. The housing 30 houses the light irradiation unit 31, the light receiving unit 32, the rotating housing 33, and the motor 34 in an internal space. Further, the housing 30 has a light transmitting portion 301. The light-transmitting portion 301 is provided on the radial side surface of the housing 30 using a material such as a light-transmitting resin or glass in the middle of the housing 30 in the axial direction. The light transmitting portion 301 is provided in an annular shape around the rotation axis J. More specifically, the light transmitting portions 301 are continuously connected over the entire circumference in the rotation direction about the rotation axis J as shown in FIG. 3A. Alternatively, without being limited to the example shown in FIG. 3A, the light transmitting portion 301 may have an arc shape extending along the rotation direction.

As described above, the distance measurement unit 3A includes the light irradiation unit 31. The light irradiation unit 31 irradiates the laser beam La to the outside of the distance measurement unit 3A. The laser light La is light in the infrared band in the present embodiment, but is not limited to this example, and may be light in a wavelength band other than the infrared band.

As shown in FIG. 3A, the light irradiation unit 31 includes an LD (Laser @ Diode) 311, a substrate 312, a collimating lens 313, and a light projecting mirror 314. The LD 311 is an example of a light source that emits laser light La. The substrate 312 mounts an LD driver 311a (see FIG. 3B) that controls light emission of the LD 311. In this embodiment, the LD 311 and the substrate 312 are fixed to the lower end surface of the upper end of the housing 30. The collimating lens 313 is arranged below the LD 311. The light projecting mirror 314 is arranged below the collimating lens 313 and is fixed to the upper end surface of the upper end of the rotating housing 33.

The LD 311 emits the laser light La downward. The laser light La emitted from the LD 311 is collimated by the collimator lens 313. The laser light La emitted downward from the collimating lens 313 is reflected by the light projecting mirror 314, passes through the light transmitting unit 301, and is emitted to the outside of the housing 30.

Next, as described above, the distance measuring unit 3A includes the light receiving unit 32. The light receiving unit 32 receives the incident light, and in particular, receives the reflected light Lb of the laser light La reflected by the object OJ located outside the automatic guided vehicle 100, for example. When the intensity of the incident light received by the light receiving unit 32 is lower than a predetermined threshold level, the detection result of the incident light is invalidated.

The light receiving unit 32 includes a light receiving lens 321, a light receiving mirror 322, a wavelength filter 323, and a light receiving element 324, as shown in FIG. 3A. The light receiving lens 321 is fitted and fixed in an opening 33 a provided on a radial side surface of the rotating housing 33. The light receiving mirror 322 is fixed to the lower end surface of the upper end of the rotating housing 33. The wavelength filter 323 is arranged below the light receiving mirror 322. The light receiving element 324 is arranged below the wavelength filter 323 and is fixed to the upper end surface of the lower end of the rotating housing 33.

The laser light La emitted from the distance measurement unit 2 is reflected by an object OJ outside the distance measurement unit 2 to become diffused light. Part of the diffused light passes through the light transmitting portion 301 and enters the light receiving portion 32 as reflected light Lb. The reflected light Lb first enters the light receiving lens 321. The reflected light Lb transmitted through the light receiving lens 321 is reflected downward by the light receiving mirror 322 and transmitted through the wavelength filter 323. At this time, the wavelength filter 323 transmits, for example, only light in the same wavelength band as the laser light La. Thereafter, the reflected light Lb is received by the light receiving element 324. The light receiving element 324 photoelectrically converts the received reflected light Lb into an electric signal and outputs the electric signal.

The light receiving section 32 receives the reflected light Lb incident from a direction parallel to the irradiation direction of the laser light La scanned in the rotation direction by the motor 34 when viewed from the direction in which the rotation axis J extends (see FIG. 2). . In this case, in each of the distance measurement units 2, the incident direction of the reflected light Lb received by the light receiving unit 32 changes according to the change in the irradiation direction of the laser light La scanned by the motor. Therefore, it is possible to suppress or prevent the light other than the reflected light Lb of the laser light La emitted from the light emitting unit 31 from being received.

Further, the light receiving section 32 further includes a comparator 325 as shown in FIG. 3B. The comparator 325 is mounted on, for example, a substrate (not shown) in the housing 30 and compares the level of an electric signal output from the light receiving element 324 with a predetermined threshold level. The electric signal indicates a result of light reception by the light receiving element 324. The comparator 325 outputs a high-level or low-level measurement pulse Pm according to the above-described comparison result. For example, when the level of the electric signal is lower than the predetermined threshold level, the comparator 325 invalidates the detection result of the incident light on the light receiving element 324 and outputs a low-level measurement pulse Pm. When the level of the electric signal is equal to or higher than the predetermined threshold level, the comparator 325 validates the detection result of the incident light by the light receiving element 324 and outputs a high-level measurement pulse Pm.

The rotating housing 33 has a hollow cylindrical shape extending in the vertical direction, and accommodates a light receiving mirror 322, a wavelength filter 323, and a light receiving element 324 in an internal space. The rotating housing 33 is fixed to a shaft 34 a of a motor 34 and can be driven to rotate by the motor 34. Due to the rotation of the rotating housing 33, the light projecting mirror 314 is also driven to rotate about the rotation axis J. Therefore, the irradiation direction of the laser beam La reflected by the light projecting mirror 314 rotates around the rotation axis J. In other words, the laser beam La is irradiated to the outside of the housing 30 while changing the irradiation direction within a range of 360 ° around the rotation axis J. Therefore, the laser beam La emitted from the light emitting unit 31 is scanned in the rotation direction about the rotation axis J in accordance with the rotation of the motor 34.

Here, the scanning range Rs1 in the rotation direction of the laser beam L1a is a measurement range in which the first distance measurement unit 21 can measure the distance to the external object OJ (see FIG. 2). The scanning range Rs1 is formed by the rotation of the laser beam L1a around the rotation axis J. Note that the scanning range Rs1 changes according to the output level of the laser light L1a. The scanning range Rs2 in the rotation direction of the laser light L2a is a measurement range in which the second distance measurement unit 22 can measure a distance to an external object. The scanning range Rs2 is formed by the rotation of the laser beam L2a around the rotation axis J. Note that the scanning range Rs2 changes according to the output level of the laser light L2a. For example, as shown in FIG. 2, when the laser light L1a irradiated within the measurement range is reflected by the object OJ located within the scanning range Rs1, the reflected light L1b passes through the light transmitting portion 301 of the first distance measurement unit 21. The light passes through and enters the light receiving lens 321. Similarly, when the laser light L2a irradiated within the measurement range is reflected by an object located within the scanning range Rs2, the reflected light of the laser light L2a transmits through the light transmission part 301 of the second distance measurement unit 22. The light enters the light receiving lens 321.

The motor 34 has a shaft 34a and a position detector 34b. The motor 34 rotates the rotating housing 33 at a predetermined rotation speed by rotating the shaft 34a. The rotation of the motor 34 causes the laser beam La to scan in the rotation direction. That is, the motor 34 is a scanning mechanism that scans the laser beam La in the rotation direction about the rotation axis J. The distance measuring unit 3A has the scanning mechanism.

Further, in the present embodiment, the motors 34 of the respective distance measurement units 2 rotate the rotary housing 33 in the same rotation direction and at the same rotation speed. Therefore, the scanning direction and the scanning speed of the laser beam La emitted from each distance measuring unit 2 are the same. For example, the scanning direction and scanning speed of the laser light L1a emitted from the first distance measurement unit 21 and the laser light L2a emitted from the second distance measurement unit 22 are the same in the present embodiment.

In this case, the laser beam La emitted from each of the distance measurement units 2 is scanned in a state where the respective irradiation directions maintain a predetermined angular width θ in the rotation direction. For example, as shown in FIG. 4, the first irradiation direction of the laser light L1a irradiated from the first distance measurement unit 21 and the second irradiation direction of the laser light L2a irradiated from the second distance measurement unit 22 are predetermined. At different angular widths θ. Each of the laser beams L1a and L2a is scanned while maintaining the angular width θ. Therefore, each distance measurement unit 2 can always irradiate the laser beam La in a different direction so that the irradiation directions are not parallel.

However, the present invention is not limited to this example, and the motors 34 of some of the distance measurement units 2 may rotate the rotating housing 33 in a rotation direction opposite to that of the motors of the remaining some of the distance measurement units 2. . That is, the scanning direction of the laser beam La emitted from some of the distance measurement units 2 may be opposite to the scanning direction of the laser beam La emitted from the remaining one of the distance measurement units 2. For example, the scanning direction of the laser light L1a emitted from the first distance measuring unit 21 may be opposite to the scanning direction of the laser light L2a emitted from the second distance measuring unit 22.

The angle width θ formed by the first irradiation direction and the second irradiation direction may be 0 ° <θ ≦ 180 °, preferably 0 ° <θ <180 °. The angle width θ is more preferably 90 °. That is, when viewed from the axial direction, the first irradiation direction of the laser light L1a irradiated from the first distance measurement unit 21 is more preferably the second irradiation direction of the laser light L2a irradiated from the second distance measurement unit 22. And orthogonal. In this way, the laser beam La emitted from one of the first distance measuring unit 21 and the second distance measuring unit 22 is not affected by the spread of the irradiation angle of the laser beams L1a and L2a. Direct reception of light by the light receiving section 32 of the other distance measuring unit 2 can be reliably prevented.

The position detection unit 34b detects the rotation angle position of the rotor of the motor 34. As described above, the motor 34 has the position detection unit 34b. The position detection unit 34b detects the rotation angle position of the laser beam La scanned in the rotation direction by the motor 34 by detecting the rotation angle position of the rotor of the motor 34. As the position detector 34b, for example, a Hall element, an encoder, or the like can be used.

<1-1-1-2. Measurement Control Unit> Next, the measurement control unit 3B of the distance measurement unit 2 will be described with reference to FIG. 3B. As shown in FIG. 3B, the measurement control unit 3B includes a measurement unit 35, an arithmetic processing unit 36, a motor driver 37, and a communication I / F 38. In the present embodiment, the measuring unit 35 and the arithmetic processing unit 36 are functional components of one or a plurality of microcomputers (not shown) provided in the measurement control unit 3B. However, the present invention is not limited to this example, and at least one of the measuring unit 35 and the arithmetic processing unit 36 may be a physical component realized by an electric circuit, an element, an electric device, or the like.

The arithmetic processing unit 36 outputs a laser emission pulse Pe to the light irradiation unit 31. At this time, the light irradiation unit 31 causes the LD 311 to emit pulsed laser light La using the laser emission pulse Pe as a trigger. When outputting the laser emission pulse Pe, the arithmetic processing unit 36 outputs the reference pulse Ps to the measuring unit 35.

The measuring unit 35 calculates the relative position of the object OJ located outside the distance measuring unit 3A with respect to the predetermined reference position based on the irradiation timing and irradiation direction of the laser beam La and the light receiving result of the light receiving unit 32. . More specifically, the measurement pulse Pm output from the comparator 325 and the reference pulse Ps output from the arithmetic processing unit 36 are input to the measurement unit 35. The measurement unit 35 acquires the distance to the object OJ by measuring the elapsed time from the rising timing of the reference pulse Ps to the rising timing of the measurement pulse Pm. That is, the measuring unit 35 measures the distance by a so-called TOF (Time @ of @ Flight) method. The measurement unit 35 outputs the measurement result to the arithmetic processing unit 36 as measurement data Dm.

At this time, preferably, in each of the distance measurement units 2, if the light receiving intensity of the light incident on the light receiving unit 32 is equal to or less than the upper limit, the measuring unit 35 sets the relative position according to the light receiving result of the light receiving unit 32. calculate. In other words, when the light receiving intensity of the light incident on the light receiving unit 32 exceeds the upper limit in the light receiving unit 32 of each distance measuring unit 2, the measuring unit 35 determines the relative position according to the light receiving result of the light receiving unit 32. Do not calculate. The upper limit is, for example, set to a value equal to or less than the light receiving intensity when the laser beam La is directly processed and received, and larger than the light receiving intensity of the reflected light Lb. Accordingly, when the distance measuring unit 2 directly receives the laser beam La emitted from, for example, another distance measuring unit or the distance measuring unit mounted on another automatic guided vehicle 100a, the distance measuring unit 2 measures the received light. The unit 35 does not calculate the relative position according to the light receiving result of the light receiving unit 32 (see FIG. 6 described later). Therefore, erroneous detection of a non-existent object and its relative position can be prevented.

The motor driver 37 controls driving of the motor 34 of the distance measuring unit 3A. The motor 34 is driven to rotate at a predetermined rotation speed by a motor driver 37. At this time, the arithmetic processing unit 36 outputs a laser emission pulse Pe every time the motor 34 rotates by a predetermined unit angle. Thus, each time the rotating housing 33 and the light projecting mirror 314 rotate by a predetermined unit angle, the light irradiation unit 31 emits the laser beam La.

The arithmetic processing unit 36 uses the distance measurement unit 2 as a reference based on the rotation angle position of the motor 34 at the timing when the laser emission pulse Pe is output and the measurement data Dm obtained corresponding to the laser emission pulse Pe. Generate position information on a rectangular coordinate system. That is, the relative position of the object OJ is obtained based on the rotation angle position of the light projecting mirror 314 and the measured distance. The position information acquired in this way is output from the arithmetic processing unit 36 as measured distance data Dd. Thus, the position information of the object OJ is obtained by the scanning of the laser beam La within the rotation scanning angle range.

The communication I / F 38 transmits the measured distance data Dd output from the arithmetic processing unit 36 to the automatic guided vehicle 100 (see FIG. 5 described later).

<1-1-2. Control Unit> Next, the configuration of the control unit 109 of the automatic guided vehicle 100 will be described. FIG. 5 is a block diagram illustrating a configuration example of the control unit 109. The control unit 109 includes the control unit 4 and the storage unit 5, as shown in FIG.

The control unit 4 communicates with an information device (not shown) such as a tablet terminal via the communication unit 108. For example, control unit 4 receives, via communication unit 108, an operation signal indicating the content of the operation input on the information device. In the present embodiment, one or more CPUs (illustration omitted) are used for the control unit 4. However, the present invention is not limited to this example, and at least a part of the control unit 4 may be an electric circuit, an element, an electronic device, or the like other than the CPU.

Further, as shown in FIG. 5, the control unit 4 includes a drive control unit 41, a scan control unit 42, a determination unit 43, a map creation unit 44, and a position identification unit 45. Note that the drive control unit 41, the scan control unit 42, the determination unit 43, the map creation unit 44, and the position identification unit 45 are functional components of the above-described CPU in the present embodiment. However, the present invention is not limited to this example, and at least one of the drive control unit 41, the scan control unit 42, the determination unit 43, the map creation unit 44, and the position identification unit 45 is an electric circuit, an element, an electric device, or the like. It may be a realized physical component.

The drive control unit 41 controls the rotational drive of the

drive motors

104L and 104R, and controls the rotational speed and the rotational direction of the

drive wheels

105L and 105R, for example.

The scanning control unit 42 controls the driving of the motor 34 of each distance measuring unit 3A, and adjusts the irradiation direction of the laser beam La emitted from each distance measuring unit 3A. More specifically, the scanning control unit 42 irradiates the laser beams La emitted from the light irradiation units 31 of the respective distance measurement units 2 in different directions. For example, the scanning control unit 42 of the first distance measurement unit 21 irradiates the laser light L1a emitted from the first distance measurement unit 21 in a direction different from the laser light L2a emitted from the second distance measurement unit 22. . In this case, since each of the distance measurement units 2 irradiates the laser beam La in a different direction, the incident direction of the incident light that can be received by the light receiving unit 32 of each of the distance measurement units 2 is also different. Therefore, for example, the reflected light Lb of the laser beam La emitted from the light irradiation unit 31 of one of the first distance measuring unit 21 and the second distance measuring unit 22 is changed to the other distance measuring unit 2 (See FIG. 2). Further, the distance measurement unit 2 can prevent the reflected light L3b of the laser light L3a emitted from the distance measurement unit mounted on another automatic guided vehicle 100a from being received by the light receiving unit 32 (see FIG. 6). ). Therefore, erroneous detection of a non-existent object and its relative position due to the reception of the reflected light Lb as described above can be prevented. The method of adjusting the irradiation direction of the laser beam La will be described later.

The determination unit 43 performs various types of determination. In addition, the determination unit 43 compares the relative positions calculated for each distance measurement unit 3A of the distance measurement unit 2. Here, the relative position refers to the relative position of the object OJ located outside the distance measuring unit 3A with respect to the predetermined reference position, as described above. The determining unit 43 determines whether or not an object is actually present at the relative position based on the result of the comparison. That is, unless a plurality of the same relative positions are calculated between the respective distance measurement units 2, the determination unit 43 determines that the object does not exist at the relative positions. For example, when the relative position calculated based on the measurement data Dm in the first distance measurement unit 21 is not calculated in the second distance measurement unit 22, the determination unit 43 determines that the object does not exist at the relative position.

In this way, the respective relative positions calculated based on the measured distance data Dd of the respective distance measuring units 2 are compared. Then, based on the result of the comparison, it is determined whether or not the object OJ exists at each relative position. For example, when there are a plurality of automatic guided vehicles 100 as shown in FIG. 6, a laser beam L4a emitted from another automatic guided vehicle 100a and a laser beam L3a emitted from another automatic guided vehicle 100a are external objects. Even if the reflected light L3b reflected by the OJ is received by one of the first distance measuring unit 21 and the second distance measuring unit 22, it is not received by the other distance measuring unit 2. In such a case, the relative position of the non-existent object is calculated by one of the distance measurement units 2, but is not calculated by the other distance measurement unit 2. Therefore, the determination unit 43 determines that the object does not exist at the relative position. Therefore, erroneous detection of a non-existent object and its position can be prevented.

At this time, if a plurality of the same relative positions are calculated between the respective distance measurement units 2, the determination unit 43 may determine that the object OJ actually exists at the relative positions. In this way, for example, if the relative positions corresponding to the results of receiving the reflected lights Lb at at least two distance measurement units 2 are the same, it is determined that the object OJ exists at the relative positions. Therefore, whether or not the object OJ actually exists at the relative position can be determined according to whether or not the same relative position is calculated between the respective distance measurement units 2.

Alternatively, the determination unit 43 compares the received light intensity of the reflected light Lb corresponding to the same relative position for each distance measurement unit 2. Then, the determination unit 43 may determine that the object OJ actually exists at the relative position if the difference in the received light intensity between the respective distance measurement units 2 is equal to or smaller than a predetermined value. On the other hand, if the difference between the received light intensities is larger than a predetermined value, the determination unit 43 may determine that the object does not exist at the relative position. In this way, for example, even if the relative position corresponding to the result of receiving the reflected light Lb at each distance measuring unit 2 is calculated, the measurement is performed based on the difference in the received light intensity between each distance measuring unit 2. Whether or not the object OJ actually exists at the relative position calculated by the unit 35 can be further determined. Therefore, it is possible to more reliably prevent a non-existent object and its position from being erroneously detected.

The map creation unit 44 creates map information based on the measured distance data Dd output from the distance measurement unit 2 and stores the map information in the storage unit 5. Note that the map information is position information of the object OJ arranged at a place where the automatic guided vehicle 100 travels, and indicates a relative position of each object OJ located outside the distance measurement unit 2 with respect to a predetermined reference position. Show. For example, when the automatic guided vehicle 100 travels in a warehouse, it is a wall of the warehouse, shelves arranged in the warehouse, luggage loaded on a road surface G in the warehouse, and the like.

The map creating unit 44 excludes the relative position of the object determined not to exist by the determining unit 43 without including the relative position in the map information.

The position identification unit 45 compares the measured distance data Dd output from the distance measurement unit 2 with the map information stored in the storage unit 5, and specifies the position of the automatic guided vehicle 100 itself based on the comparison result. Self-position identification. By performing the self-position identification, the control unit 4 can control the autonomous traveling of the automatic guided vehicle 100 along a predetermined route.

The storage unit 5 is a non-transitory storage medium that can retain storage even when power supply is stopped. The storage unit 5 stores programs and information used by the control unit 109 or the control unit 4.

<1-1-3. Method of Adjusting Irradiation Direction> Next, a method of adjusting the irradiation direction of the laser beam La emitted from each distance measurement unit 2 by the scanning control unit 42 will be described. FIG. 7 is a flowchart for explaining a method of adjusting the irradiation direction of the laser beam La in the embodiment.

When the operation of each distance measurement unit 2 is started (step S101), the rotation angle position of the rotor of the motor 34 is detected by the position detection unit 34b in each distance measurement unit 2 (step S102). That is, the irradiation direction of the laser beam La emitted from each distance measurement unit 2 is detected.

The scanning control unit 42 calculates the angular width θ between the irradiation directions of the respective laser beams La by calculating the difference between the rotation angle positions of the rotors in the respective distance measurement units 2. If the angle width θ is not the predetermined constant value θc (NO in step S103), the scanning control unit 42 controls the motor 34 in at least one distance measuring unit 2 so that the angle width θ becomes the constant value θc. Is adjusted (step S104). Thereafter, the scanning control unit 42 returns the processing to Step S102. Alternatively, without being limited to this example, the scanning control unit 42 may end the processing in FIG.

On the other hand, if the angle width θ is the predetermined constant value θc (YES in step S103), the scanning control unit 42 ends the processing in FIG.

Note that the predetermined constant value θc is, for example, 90 °, but is not limited to this example, and may be a predetermined value within a predetermined range. That is, the scanning control unit 42 may adjust the angle width θ to a predetermined value within a predetermined range. The predetermined range is, for example, 0 ° <θ ≦ 180 °, preferably 0 ° <θ <180 °.

As described above, the scanning control unit 42 adjusts the scanning speed of the at least one distance measuring unit 3A in the irradiation direction of the laser beam La based on the detection result of the position detecting unit 34b. With this adjustment, the scanning control unit 42 sets the difference between the rotation angle positions of the irradiation directions of the laser light La in the respective distance measurement units 3A to a predetermined constant value. This makes it possible to maintain a constant angular width θ (see FIG. 4) between the irradiation directions of the laser beam La in each of the distance measurement units 3A.

<1-2. Distance measuring device> The automatic guided vehicle 100 includes the distance measuring device 1. The distance measuring device 1 detects an object OJ located outside the automatic guided vehicle 100, and detects a distance to the object OJ and an azimuth where the object OJ is located with respect to the position of the automatic guided vehicle 100. Thereby, the automatic guided vehicle 100 can create map information around itself and identify its own position.

The distance measurement device 1 includes a plurality of distance measurement units 2 including a first distance measurement unit 21 and a second distance measurement unit 22, and a part of the control unit 109 (see FIG. 5). More specifically, in the present embodiment, the distance measurement device 1 includes a plurality of distance measurement units 3A, a measurement unit 35, a scan control unit 42, a determination unit 43, a map creation unit 44, a position identification unit 45.

The plurality of distance measurement units 3A included in the distance measurement device 1 include a distance measurement unit of the first distance measurement unit 21 and a distance measurement unit of the second distance measurement unit 22. In the present embodiment (see FIG. 2), the distance measuring unit of the first distance measuring unit 21 is disposed on the right D3R side at the front end of the automatic guided vehicle 100. The distance measuring unit of the second distance measuring unit 22 is disposed on the left D3L side at the front end of the automatic guided vehicle 100. Here, the “right D3R side” and the “left D3L side” are respectively examples of one side and the other side in a horizontal direction intersecting with the direction D1f in which the automatic guided vehicle 100 moves forward.

In this case, at the front end of the automatic guided vehicle 100, the distance measuring unit of the first distance measuring unit 21 and the distance measuring unit of the second distance measuring unit 22 can be arranged apart in the left-right direction D3. Therefore, the object OJ located outside the distance measuring device 1 and its relative position can be detected in a wider range. In addition, the laser beam La emitted from the distance measuring device mounted on the other automatic guided vehicle 100a and / or the reflected light Lb derived from the distance measuring device mounted on the other automatic guided vehicle 100a is the first distance. It is difficult for both the distance measurement unit of the measurement unit 21 and the distance measurement unit of the second distance measurement unit 22 to receive light. It becomes easier to prevent erroneous detection of a non-existent object and its position.

The arrangement of the distance measuring units 3A of the first distance measuring unit 21 and the second distance measuring unit 22 is not limited to the example of the present embodiment. FIG. 8 is a top view illustrating another arrangement example of the distance measuring unit 3A of the distance measuring unit 2. As illustrated in FIG. 8, the distance measuring unit of the second distance measuring unit 22 may be disposed on the left D3L side at the rear end of the automatic guided vehicle 100. Here, the “right D3R side” and the “left D3L side” are respectively examples of one side and the other side in a horizontal direction intersecting with the direction D1f in which the automatic guided vehicle 100 moves forward.

In this case, the distance measurement unit of the first distance measurement unit 21 and the distance measurement unit of the second distance measurement unit 22 can be arranged apart from each other in the diagonal direction of the automatic guided vehicle 100 across the front D1f. Therefore, the distance between the distance measuring unit of the first distance measuring unit 21 and the distance measuring unit of the second distance measuring unit 22 is further increased. Therefore, the object OJ located outside the distance measuring device 1 and its relative position can be detected in a wider range.

In addition, the laser beam La emitted from the distance measuring device mounted on the other automatic guided vehicle 100a and / or the reflected light Lb derived from the distance measuring device mounted on the other automatic guided vehicle 100a is the first distance. It is difficult for both the distance measurement unit of the measurement unit 21 and the distance measurement unit of the second distance measurement unit 22 to receive light. Therefore, it becomes easier to prevent erroneous detection of a non-existent object and its position.

Note that the distance measuring unit of the first distance measuring unit 21 is not limited to the example illustrated in FIG. 8 and may be disposed on the right D3R side at the rear end of the automatic guided vehicle 100. Further, the distance measuring unit of the second distance measuring unit 22 may be disposed on the right D3R side at the front end of the automatic guided vehicle 100.

As described above, the automatic guided vehicle 100 includes the distance measuring device 1. Thereby, the distance measuring device 1 that can prevent the object OJ located outside the distance measuring device 1 and its position from being erroneously detected can be mounted on the automatic guided vehicle 100.

<2. Modified Example> Next, a modified example of the embodiment will be described, which is different from the above-described embodiment. FIG. 9 is a top view of the automatic guided vehicle 100 according to the modification. FIG. 10 is a cross-sectional view illustrating a configuration example of a distance measuring unit 3A of a distance measuring unit 2 according to a modification. Since FIG. 9 illustrates the vicinity of the automatic guided vehicle 100, a part of the scanning ranges Rs1 and Rs2 of each distance measuring unit 2 is illustrated. In the following, the same components as those in the above-described embodiment are denoted by the same reference numerals, and description thereof may be omitted.

In a modified example, in each distance measurement unit 2, the housing 30 of the distance measurement unit 3A shields light between the light irradiation unit 31 and the light reception unit 32 and the distance measurement unit of another distance measurement unit. Therefore, the light transmitting portion 301 has an arc shape extending along the rotation direction. As shown in FIG. 9, by the light shielding of the housing 30, as shown in FIG. And the laser beam La can be more reliably prevented from entering.

Further, in each of the distance measurement units 2, as shown in FIG. 10, the distance measurement unit 3A further includes a light reflecting member 39. The light reflecting member 39 is provided on the inner side surface of the housing 30 radially outward of the rotating housing 33. The light reflecting member 39 is fixed at a predetermined rotation angle position, and reflects the pulsed laser light La emitted from the light emitting unit 31 toward the light receiving unit 32. The light receiving unit 32 detects the reflected light Lp incident from the light reflecting member 39. Note that the reflected light Lp is a pulse light in which the pulsed laser light La is reflected by the light reflecting member 39.

Next, a description will be given of a method in which the scanning control unit 42 adjusts the irradiation direction of the laser beam La emitted from each of the distance measurement units 2 in a modified example. FIG. 11 is a flowchart for explaining a method of adjusting the irradiation direction of laser light in the modification.

When the measuring operation of each distance measuring unit 2 is started (Step S201), the measuring unit 35 of each distance measuring unit 3A measures the light receiving timing of the reflected light Lp (Step S202).

The scanning control unit 42 calculates the difference ΔT between the light receiving timings of the reflected light Lp in each distance measuring unit 3A. If the difference ΔT between the light receiving timings is not the predetermined constant value ΔTc (NO in step S203), the scanning control unit 42 controls the at least one distance measuring unit 2 so that the difference ΔT between the light receiving timings becomes the constant value ΔTc. The rotation speed of the motor 34 is adjusted (step S204). Thereafter, the scanning control unit 42 returns the processing to Step S202. Alternatively, without being limited to this example, the scanning control unit 42 may end the processing in FIG.

On the other hand, if the difference ΔT between the light receiving timings is a predetermined constant value θc (YES in step S203), the scanning control unit 42 ends the processing in FIG.

In step 204 of FIG. 11, the scanning control unit 42 adjusts the scanning speed of the laser beam La by the motor 34 in the distance measuring unit 3A of at least one distance measuring unit 2 so that the pulse shape in each distance measuring unit 3A is adjusted. Of the light receiving timing of the reflected light Lp is set to a predetermined constant value ΔTc. In this case, the difference between the light receiving timings of the pulse-like reflected light Lp reflected by the light reflecting member 39 in each of the distance measuring units 3A is set to a predetermined constant value, so that the laser in each of the distance measuring units 3A is changed. The scanning speed of the light and the angular width θ in the irradiation direction of the laser light between the respective distance measuring units 3A can be kept constant.

The scanning control unit 42 is not limited to the example illustrated in FIG. 11, and may perform adjustment in steps S <b> 203 and S <b> 204 so that the difference ΔT between the light receiving timings is within a predetermined constant value ΔTc.

<3. Others> The exemplary embodiments of the present disclosure have been described above. Note that the scope of the present invention is not limited to the above disclosure. The present disclosure can be implemented with various modifications without departing from the spirit of the invention. In addition, matters described in the present disclosure can be arbitrarily combined as appropriate without causing contradiction.

For example, in the above-described embodiment and its modifications, the measurement control unit 3B that controls the distance measurement unit 3A is provided for each distance measurement unit 2. However, the present invention is not limited to this example, and the measurement control unit 3B may be provided separately from each of the distance measurement units 2 and control a plurality of distance measurement units 3A. Further, at least a part of the measurement control unit 3B may be provided in the control unit 4. For example, the measurement unit 35 may be provided in the control unit 4.

The present disclosure is useful for an apparatus having a plurality of distance measurement units.

100, 100a: automatic guided vehicle, 101: body, 102: carrier, 103L, 103R: support, 104L, 104R: drive motor, 105L, 105R: drive wheel, 106F , 106R: driven wheel, 107: battery, 108: communication unit, 109: control unit, 1 ... distance measuring device, 2 ... distance measuring unit, 21 ... first Distance measuring unit, 22: second distance measuring unit, 3A: distance measuring unit, 3B: measuring control unit, 30: housing, 301: translucent unit, 31: light Irradiating unit 311 LD, 311a LD driver, 312 substrate, 313 collimating lens, 314 projecting mirror, 32 light receiving unit, 321 light receiving lens 322: light receiving mirror, 23 ... wavelength filter, 324 ... light receiving element, 325 ... comparator, 33 ... rotary housing, 33a ... opening, 34 ... motor, 34a ... shaft, 34b ... Position detecting section, 35 measuring section, 36 processing section, 37 motor driver, 38 communication I / F, 39 light reflecting member, 4 control section, 41: drive control unit, 42: scan control unit, 43: determination unit, 44: map creation unit, 45: position identification unit, 5: storage unit, rotation Axes, La, L1a, L2a: laser light, Lb, L1b, L3b, Lp: reflected light, G: road surface, OJ: object, θ: angular width, θc: constant Value, ΔT: difference in light receiving timing, ΔTc: constant value, Rs, Rs1, Rs2: scanning range, D1 ·・・ Vertical direction, D1d ・・・ Vertical downward, D1t ・・・ Vertical upward, D2f ・・・ Front, D2r ・・・ Backward, D3 ・・・ Left and right direction, D3L ・・・ Left, D3R ・・・ Right One

Claims

A plurality of distance measuring units, a measuring unit, a scanning control unit, and a determining unit, wherein the distance measuring unit is: a light irradiating unit that irradiates a laser beam outside the distance measuring unit; A light receiving unit that receives the reflected light; and a scanning mechanism that scans the laser light in a rotational direction about a rotation axis, and the scanning control unit drives the scanning mechanism of each of the distance measuring units. Controlling the laser light emitted from the light irradiating unit of each of the distance measuring units in different directions, the measuring unit, the irradiation timing of the laser light and the irradiation direction and the light receiving unit Based on the light receiving result, a relative position of an object located outside the distance measurement unit with respect to a predetermined reference position is calculated, and the determination unit calculates each of the relative positions calculated for each of the distance measurement units. And compare the It said object on the relative position based on the result of the compare and determines whether the actual distance measuring device.
2. The light receiving unit according to claim 1, wherein the light receiving unit receives the reflected light incident from a direction parallel to an irradiation direction of the laser light scanned in the rotation direction by the scanning mechanism when viewed from a direction in which the rotation axis extends. 3. Distance measuring device.
3. The distance measuring device according to claim 1, wherein the determining unit determines that the object is actually present at the relative position if a plurality of the same relative positions are calculated between the distance measuring units. 4.
The determination unit compares the received light intensity of the reflected light corresponding to the same relative position for each of the distance measuring units, and if the difference in the received light intensity between each of the distance measuring units is equal to or less than a predetermined value, The distance measuring device according to claim 1, wherein it is determined that the object exists at a relative position.
The said measurement part calculates the said relative position according to the light-receiving result of this light-receiving part, if the light-receiving intensity of the light which injects into the said light-receiving part is less than an upper limit in each said distance measurement part. The distance measuring device according to any one of claims 1 to 4.
The distance measuring device according to any one of claims 1 to 5, wherein a scanning direction and a scanning speed of the laser light emitted from each of the distance measuring units are the same.
The plurality of distance measurement units include a first distance measurement unit and a second distance measurement unit, and when viewed from the -axis direction, the first irradiation direction of the laser light emitted from the first distance measurement unit is 7. The distance measuring device according to claim 6, wherein the laser beam emitted from the second distance measuring unit is orthogonal to a second irradiation direction.
The scanning mechanism has a position detection unit that detects a rotation angle position in an irradiation direction of the laser light that is scanned in a rotation direction by the scanning mechanism. By adjusting the scanning speed in the irradiation direction of the laser light based on the detection result of the position detection unit, the difference between the rotation angle positions in the irradiation direction of the laser light in each of the distance measurement units is a predetermined constant value. The distance measuring device according to any one of claims 1 to 7, wherein:
The distance measurement unit further includes a housing that houses the light irradiation unit and the light receiving unit, and the housing shields light between the light irradiation unit and the light reception unit and another distance measurement unit. The distance measuring device according to any one of claims 1 to 8.
The distance measuring unit further includes a light reflecting member fixed at a predetermined rotation angle position and reflecting the pulse light emitted from the light emitting unit toward the light receiving unit, and the scanning control unit includes: Adjusting a scanning speed of the laser beam by the scanning mechanism in at least one of the distance measurement units to make a difference between light reception timings of the pulse light in each of the distance measurement units a predetermined constant value. The distance measuring device according to any one of claims 1 to 9.
A moving object that travels on a road surface, and is provided with the distance measuring device according to any one of claims 1 to 10.
The plurality of distance measuring units included in the distance measuring device include a first distance measuring unit and a second distance measuring unit, and the first distance measuring unit is configured such that the moving body moves forward at a front end of the moving body. The moving body according to claim 11, wherein the moving body is arranged on one side in a horizontal direction intersecting with the moving direction, and the second distance measuring unit is arranged on the other side in the horizontal direction at a front end of the moving body.
The plurality of distance measuring units included in the distance measuring device include a first distance measuring unit and a second distance measuring unit, and the first distance measuring unit includes a moving body at a front end of the moving body. The movement according to claim 11, wherein the second distance measurement unit is disposed on one side in a horizontal direction intersecting with the forward direction, and the second distance measurement unit is disposed on the other end in the horizontal direction at a rear end of the moving body. body.