JP2024034338A - distance measuring device - Google Patents

Abstract

[Problem] To provide a distance measuring device capable of ensuring a wide range of measurable distances. [Solution] This distance measuring device (100) is a distance measuring device that measures the distance to an object (200), and has an irradiation unit (120), a second lens (7) that transmits return light (R), which is light that is light (L2) from the irradiation unit reflected or scattered by the object, a light receiving unit (8) that outputs light reception information based on the return light (R) that has transmitted through the second lens, and an output unit that outputs distance information to the object based on the light reception information (S) from the light receiving unit, and a first lens (4) that determines the spread angle β of light (LO) from the light emitting unit (3) so that the diameter of the light (L2) irradiated by the irradiation unit (120) is minimized at a predetermined position of the object that is the maximum measurable distance away, and d/f of the second lens is smaller than beta, where f is the focal length of the second lens and d is the effective diameter of one of the light receiving units. [Selected Figure] Figure 4

Description

The present invention relates to a distance measuring device.

2. Description of the Related Art Distance measuring devices that measure distances to objects have been known in the past. Such distance measuring devices are mounted on moving bodies such as robots, automobiles, and flying bodies, and are used in applications such as recognizing objects existing around the moving body.

The distance measuring device includes a light emitting/receiving section, and a first deflection mechanism and a second deflection mechanism that scan the light projected from the light emitting/receiving section. A device has been disclosed that measures the distance between the object and the object based on the time difference between the time when the reflected light from the object is received (for example, see Patent Document 1).

JP2014-109686A

A distance measuring device is required to have a wide measurable distance range.

An object of the present invention is to provide a distance measuring device that can secure a wide range of measurable distances.

This distance measuring device (100) is a distance measuring device that measures the distance to an object (200), and includes a first lens (4) that transmits light (L0) from a light emitting section (3); An irradiation unit (120) that irradiates the object (200) with the light (L2) that has passed through the first lens (4), and the light (L2) from the irradiation unit (120) is reflected or scattered by the object (200). A second lens (7) that transmits the return light (R) that is light, a light receiver (8) that outputs light reception information based on the return light (R) that has passed through the second lens (7), and a light receiver. (8), and an output section (405) that outputs distance information (Dt) between the object (200) and the object (200) based on the light reception information (S) from the first lens (4). from the light emitting part (3) so that the diameter of the light (L2) irradiated by the irradiating part (120) is minimized at the position of the object (200) which is the maximum measurable distance (Lx) away from the object (200). If the spread angle β of the light (L0) is defined, the focal length of the second lens (7) is f, and the effective diameter of one of the light receiving parts is d, then the second lens (7) can be calculated using the following formula (1). satisfy.

Note that the reference numerals in parentheses above are added to facilitate understanding, are merely an example, and are not limited to the illustrated embodiments.

According to the present invention, it is possible to provide a distance measuring device that can ensure a wide range of measurable distances.

1 is a perspective view illustrating the overall configuration of a distance measuring device according to an embodiment. FIG. 2 is a perspective view illustrating the vicinity of a light emitting section and a light receiving section in the distance measuring device of FIG. 1. FIG. FIG. 2 is a perspective view illustrating an irradiation section in the distance measuring device of FIG. 1. FIG. FIG. 1 is a block diagram of a configuration example of a distance measuring device according to an embodiment. 5(a) is a side view of the light splitting member, FIG. 5(b) is a perspective view of the light splitting member, and FIG. 5(c) is a front view of the light splitting member. It is a diagram. It is a figure of the example of composition of the synchronization detection part of the range finder concerning an embodiment. FIG. 3 is a diagram illustrating an example of scanning light irradiation in the distance measuring device according to the embodiment. FIG. 7 is a diagram illustrating an example of the relationship between the distance to an object and the diameter of the returned light according to a comparative example. FIG. 6 is a diagram illustrating an example of the relationship between the distance to an object and the diameter of the returned light according to the embodiment. It is a figure which illustrates the space|interval between adjacent light receiving parts. FIG. 3 is a diagram illustrating a hardware configuration example of a control unit of a distance measuring device according to an embodiment. FIG. 2 is a block diagram of an example of a functional configuration of a control unit of a distance measuring device according to an embodiment. It is a flowchart of the example of a process by the control part of the distance measuring device based on embodiment.

Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In each drawing, the same components are designated by the same reference numerals, and redundant explanations will be omitted as appropriate.

The embodiments shown below illustrate distance measuring devices for embodying the technical idea of the present invention, and the present invention is not limited to the embodiments shown below. The dimensions, materials, shapes, relative positions, etc. of the components described below are not intended to limit the scope of the present invention, unless otherwise specified, but are intended to be illustrative. It is something. Further, the sizes, positional relationships, etc. of members shown in the drawings may be exaggerated for clarity of explanation.

In the figures shown below, directions may be indicated by the X-axis, Y-axis, and Z-axis, but the Z direction along the Z-axis refers to the second Indicates the direction along the axis. The X direction along the X axis indicates a direction intersecting the Z direction. The Y direction along the Y axis indicates a direction that intersects both the X axis and the Z axis.

In addition, the direction in which the arrow is pointing in the X direction is expressed as +X direction, the direction opposite to +X direction is expressed as -X direction, the direction in which the arrow is pointing in Y direction is expressed as +Y direction, and the direction opposite to +Y direction is expressed as -Y direction. The direction in which the arrow is pointing in the Z direction is written as +Z direction, and the direction opposite to +Z direction is written as -Z direction. However, these do not limit the direction in which the range finder is used, and the range finder can be placed in any direction.

[First embodiment]
Hereinafter, embodiments will be described using, as an example, a distance measuring device that is mounted on a service robot and measures the distance between the service robot and an object existing in the direction of movement of the service robot or around it using a TOF (Time of Flight) method.

A service robot is an autonomous mobile object that is mainly used for service purposes, such as transporting materials within a factory, transporting goods and providing guidance at a customer service facility, security within a facility, or cleaning. A moving object is an object that can be moved. A distance measuring device mounted on a service robot is used to detect objects existing in the direction of movement of the service robot or around it, and to create a map of the facility where the service robot operates.

<Example of configuration of distance measuring device 100>
(overall structure)
An example of the configuration of a distance measuring device 100 according to an embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view illustrating the overall configuration of a distance measuring device 100. FIG. 2 is a perspective view illustrating the vicinity of a light emitting section and a light receiving section in the distance measuring device 100. FIG. 3 is a perspective view illustrating the irradiation unit 120 in the distance measuring device 100.

The distance measuring device 100 measures the distance to an object. As shown in FIGS. 1 to 3, the distance measuring device 100 includes an irradiation section 120, a stand section 1, a holding section 2, a light emitting section 3, a first lens 4, a perforated mirror 6, and a second It has a lens 7, five light receiving sections 8, and a tombstone 9.

The irradiation unit 120 irradiates an object with scanned light. In this embodiment, the irradiation unit 120 includes a rotating reflector 5 and a rotating stage 10. The irradiation unit 120 irradiates the object with light scanned in a first direction and a second direction intersecting the first direction. In this embodiment, the first direction corresponds to the area around A1 (in the case of the arrangement of FIG. 1, the vertical direction). The first direction will be described separately in the explanation using FIG. 10. The second direction is a direction corresponding to the area around A2 (also in the horizontal direction in the case of the arrangement shown in FIG. 1).

The table part 1 is a flat member provided with a holding part 2 and a rotation stage 10. The base portion 1 fixes the holding portion 2 and the rotation stage 10 in mutually different areas on the −Z direction side surface. The rotation stage 10 is fixed to a region on the +Y direction side of the base portion 1 by screw members or the like. The holding part 2 is fixed to a region of the base part 1 on the −Y direction side of the rotation stage 10 via a coupling member 11 with a screw member or the like.

There is no particular restriction on the material of the base portion 1, but since the rotation stage 10 may be heavy, it is preferable to include a material with high rigidity such as a metal material. The platform section 1 is not limited to a flat plate-like member, and may be any other structure as long as the rotation stage 10 and the holding section 2 can be installed thereon. For example, when the holding part 2 and the rotation stage 10 are installed in the casing of a service robot, the casing of the service robot corresponds to the platform.

The holding part 2 is a member formed by combining a ceiling panel 21 and a back panel 22. The ceiling panel 21 and the back panel 22 are each flat members. There is no particular restriction on the material of the ceiling panel 21 and the back panel 22, and for example, a metal material or a resin material can be used.

A light emitting section 3, a first lens 4, and a perforated mirror 6 are provided on the surface of the ceiling panel 21 on the +Z direction side. A second lens 7 and five light receiving sections 8 are provided on the surface of the back panel 22 on the +Y direction side.

The light emitting section 3 emits light. For example, the light emitting unit 3 is an LD (Laser Diode). The light emitting unit 3 emits laser light L0, which is pulsed light, in the +Z direction. However, the light emitting section may be an LED (light emitting diode) or the like. The wavelength of the laser beam L0 is preferably a laser beam in an invisible wavelength region such as a near-infrared wavelength region, since distance measurement can be performed without the laser light being visually recognized by humans.

The first lens 4 is configured to include a glass material or a resin material. The first lens 4 substantially collimates (substantially parallelizes) the laser beam L0. The first lens 4 is not an essential component. However, by including the first lens 4, the distance measuring device 100 can suppress the spread of the laser light L0 emitted from the light emitting section 3, and can improve light utilization efficiency.

The laser beam L0 collimated by the first lens 4 enters the light splitting member 41. The light splitting member 41 splits the laser beam L0 from the light emitting section 3 into a plurality of parts. The light splitting member 41 is, for example, a diffraction grating. The light splitting member 41 splits the laser beam L0 into five divided beams L1. The five divided lights L1 enter the rotating reflector 5 after passing through the through hole 61 provided in the perforated mirror 6. The number of divided beams L1 can be appropriately selected depending on the required spatial resolution, etc., as long as it is plural. Note that details of the five divided lights L1 obtained by the light splitting member 41 will be described separately with reference to FIG. 5.

The rotating reflector 5 has six light reflecting surfaces 51. The rotating reflector 5 irradiates an object with five divided beams L1 that are scanned by changing the angle of the light reflecting surface 51 through rotation. The scanning light L2 in FIG. 1 is the reflected light of the divided light L1 by the light reflecting surface 51, and corresponds to the scanned light. In other words, the irradiation unit 120 can irradiate the object with five scanning lights L2, each of which is scanned by each of the five divided lights L1 split by the light splitting member 41.

In FIG. 1, in order to simplify the diagram, only one of the five divided beams L1 and only one of the five scanning beams L2 are shown. Further, in FIG. 1, one of the five scanning lights L2 is displayed as one laser beam that is irradiated in the +Y direction at an arbitrary timing.

The rotating reflector 5 is, for example, a polygon mirror. A polygon mirror is a rotating polygon mirror. The shape of the rotating reflector 5 when viewed from the direction along the first axis A1 is approximately a regular hexagon. The rotating reflector 5 has six light reflecting surfaces 51 on the outer peripheral surface corresponding to each side of a regular hexagon. The rotating reflector 5 can be manufactured by cutting or mirror polishing the outer peripheral surface of a substantially regular hexagonal columnar member made of a metal material such as aluminum. However, the rotating reflector 5 may be manufactured by mirror-depositing aluminum or the like on the outer peripheral surface of a rotating body made of a metal material, a resin material, or the like.

The number of light reflecting surfaces 51 is not limited to six, and may be one or more. The scanning angle range of light by the rotating reflector 5 differs depending on the number of light reflecting surfaces 51. For example, the greater the number of light reflecting surfaces 51, the narrower the scanning angle range, and the smaller the number of light reflecting surfaces 51, the wider the scanning angle range. The number of light reflecting surfaces 51 can be determined as appropriate depending on the required scanning angle range.

A first axis motor is attached to the rotary reflector 5 so that the central axis of the rotary reflector 5 and the rotation axis substantially coincide with each other. The rotating reflector 5 rotates around the first axis A1 using the first axis motor as a driving source. It can also be said that the five divided beams L1 are scanned in the circumferential direction of a circle centered on the first axis A1. The rotating direction of the rotating reflector 5 is constant. For example, the rotating reflector 5 continuously rotates along the first axis rotation direction A11 in FIG. However, the rotating reflector 5 may continuously rotate in a direction opposite to the first axis rotation direction A11.

In FIG. 1, when an object exists on the +Y direction side of the range finder 100 at a certain time, the five scanning lights L2 are reflected or scattered by the object and return light toward the range finder 100 in the -Y direction. be returned. The returned light enters the light reflecting surface 51 of the rotating reflector 5 again and is reflected by the light reflecting surface 51 in the -Z direction. Of the returned light reflected in the -Z direction, the returned light that is incident on the mirror surface of the perforated mirror 6 is reflected by this mirror surface in the -Y direction and reaches the five light receiving sections 8. In this embodiment, the light reflecting surface 51 on which the five divided lights L1 are reflected and the light reflecting surface 51 on which the return light is reflected are the same surface. Note that depending on the rotational position of the irradiation unit 120 around the A2 axis and the rotational position of the rotary reflector 5 around the A1 at a time different from the time in the state of FIG. Not limited to direction. However, the point at which the irradiated light is reflected by an object, returned toward the distance measuring device 100, enters the light reflecting surface 51, and is reflected in the -Z direction is at a different time from the time in the state of FIG. The same is true.

The perforated mirror 6 is a light deflection unit that deflects returned light that is the result of the scanning light L2 being reflected or scattered by an object. The perforated mirror 6 includes a through hole 61. The through hole 61 is an opening through which light emitted by the light emitting section 3 passes. The through hole 61 is formed in a part of the region of the perforated mirror 6 where the mirror surface is provided. Of the light that enters the perforated mirror 6, the light that enters the mirror surface is reflected, and the light that enters the through hole 61 passes through the through hole 61.

The perforated mirror 6 allows the laser beam L0 collimated by the first lens 4 to pass through the through hole 61. Further, the perforated mirror 6 reflects the returned light, which is the result of the scanning light L2 being reflected or scattered by an object, toward the five light receiving sections 8 using the mirror surface. The return light reflected by the mirror surface of the perforated mirror 6 is collected by the second lens 7 and enters the five light receiving sections 8 .

The opening of the light deflection section is not limited to a through hole, but may be a transparent region provided in a part of the mirror surface of the light deflection section. Furthermore, a beam splitter, a half mirror, or the like can also be used as the light deflection section.

The five light receiving units 8 output light reception information for each scanning angle of each of the five scanning lights L2 based on return light obtained by reflecting or scattering the five scanning lights L2 emitted from the irradiation unit 120 by an object. . "Every scanning angle" means "every angle at which the scanning light is scanned per unit time."

The five light receiving sections 8 include light receiving sections 81 to 85 that are paired with each of the five divided lights L1 divided by the light splitting member 41. Each of the light receiving units 81 to 85 detects the scanning angle of each of the five scanning lights L2 based on the return light that is reflected or scattered by the object, and the pair of scanning lights L2 of the five divided lights L1. Outputs light reception information.

Each of the light receiving sections 81 to 85 is, for example, an APD (Avalanche Photodiode). APD is a type of photodiode that uses a phenomenon called avalanche multiplication to improve light receiving sensitivity. However, each of the light receiving sections 81 to 85 may be a photodiode, a photomultiplier tube, or the like.

The tombstone 9 is a member including a bent portion. The tombstone 9 supports the rotating reflector 5. The surface of the tombstone 9 on the −Z direction side contacts the mounting surface 101 of the rotation stage 10, and is fixed onto the mounting surface 101 by screw members or the like. The tombstone 9 supports the rotating reflector 5 on a surface on the +X direction side intersecting the bottom surface with a substrate 91 interposed therebetween. There is no particular restriction on the material of the tombstone 9, but in order to ensure high rigidity, it is preferable to include a highly rigid material such as metal.

The rotation stage 10 is rotatable while supporting the rotation reflector 5. The rotation stage 10 rotates the rotary reflector 5 around the second axis A2 by rotating the tombstone 9 around the second axis A2. The five scanning lights L2 by the rotating reflector 5 are scanned in the second direction by the rotation of the rotating stage 10. It can also be said that the five scanning lights L2 are scanned in the circumferential direction of a circle centered on the second axis A2.

The rotation stage 10 is provided on the platform 1 in a different area from the area where the holding part 2 is provided. Therefore, even if the rotary stage 10 rotates, the holding section 2 and the light emitting section 3 and the five light receiving sections 8 held by the holding section 2 remain immovable and remain fixed to the base section 1.

As shown in FIG. 3, the rotation stage 10 includes a mounting surface 101, a bearing 102, a magnet 103, and a motor core 104.

The mounting surface 101 is a surface that is substantially perpendicular to the second axis A2 and rotatable around the second axis A2. The tombstone 9 is placed on the placement surface 101. The bearing 102 is a member that makes rotation of the mounting surface 101 smooth. A ball bearing, a cross roller bearing, or the like may be applied to the bearing 102.

Magnet 103 is made of a permanent magnet. The motor core 104 is a member corresponding to the iron core of the stator that constitutes the motor. A motor includes a magnet 103 and a motor core 104. As the magnet 103 rotates in response to the current, the mounting surface 101 rotates via the bearing 102.

The rotation direction of the rotation stage 10 is constant, and corresponds to the second axis rotation direction A21 in FIG. 1, for example. However, the rotation stage 10 may continuously rotate in a direction opposite to the second axis rotation direction A21.

The distance measuring device 100 is configured such that the optical axis of the laser beam L0 and the second axis A2 are coaxial. The optical axis of the laser beam L0 means an axis passing through the center of the laser beam L0 along the propagation direction of the laser beam L0. Moreover, coaxial means that a plurality of axes substantially coincide with each other.

The scanning light L2 is scanned in a direction intersecting the first axis A1 by the rotation of the rotary reflector 5, and is scanned in a direction intersecting the second axis A2 by the rotation of the rotary stage 10. The direction intersecting the second axis A2 is, for example, a horizontal direction substantially perpendicular to the direction of gravity. The first axis A1 may be arranged at an angle with respect to the second axis A2.

The distance measuring device 100 may include an exterior cover for covering part or all of the components such as the light emitting unit 3, the rotating reflector 5, the five light receiving units 8, or the rotating stage 10. Providing the exterior cover prevents dirt, dust, etc. from entering the inside of the distance measuring device 100, and prevents dirt, dust, etc. from adhering to the rotary reflector 5 and the like. Furthermore, when the rotary reflector 5 or the rotary stage 10 rotates at high speed, wind noise accompanying the rotation may become louder. By providing an exterior cover, it is possible to suppress the transmission of sound to the surroundings. Metal or resin material can be used as the material of the exterior cover.

On the other hand, when the exterior cover is provided, the scanning light L2 is blocked by a portion of the exterior cover other than the exit window from which the scanning light L2 is emitted, so the scanning angle range is limited, and the range of detection of the object 200 by the distance measuring device 100 or distance measurement is limited. Range may be limited. If the exterior cover is made of a transparent resin material that is transparent to the wavelength of the scanning light L2, such restrictions on the scanning angle range can be relaxed.

FIG. 4 is a block diagram illustrating the configuration of the distance measuring device 100. Note that the solid line arrows in FIG. 4 indicate the flow of light, and the broken line arrows indicate the flow of electrical signals. As shown in FIG. 4, the distance measuring device 100 includes a light receiving/emitting section 110, an irradiation section 120, an emission window 130, and a control section 140.

The irradiation unit 120 includes a rotating reflector 5, a rotating stage 10, and a drive control unit 150. The irradiation unit 120 irradiates the object 200 with five scanning lights L2 by controlling the rotations of the rotary reflector 5 and the rotary stage 10 using the drive control unit 150.

The drive control section 150 includes a first axis motor 151, a second axis motor 152, a synchronization detection section 153, a rotation control section 402, and a power supply section 155. The drive control unit 150 controls the rotation by the second axis motor 152 using the rotation control unit 402 based on the synchronization signal Sn corresponding to the rotation period of the rotary reflector 5 output from the synchronization detection unit 153.

The synchronization detection section 153 includes a first axis encoder 531, a periodic light emitting section 532, and a periodic light receiving section 533. The synchronization detection section 153 causes the periodic light emitting section 532 to emit light based on the first angle detection signal En1 output from the first axis encoder 531, and causes the periodic light receiving section 533 that receives the light from the periodic light emitting section 532 to emit light. A synchronization signal Sn is output. The first angle detection signal En1 is a detection signal of the rotation angle of the rotary reflector 5.

The periodic light emitting unit 532 is configured to include, for example, an LED, and emits pulsed light at the timing when, for example, the first axis encoder 531 detects an angle corresponding to the rotation origin of the rotary reflector 5 based on the first angle detection signal En1. Emit Op.

The periodic light receiving section 533 is configured to include a photo diode, etc., and outputs a synchronizing signal Sn via the second axis driver board 173 at the timing of receiving the pulsed light Op generated by the periodic light emitting section 532. is output to the rotation control section 402.

The power feeding unit 155 includes a power generation coil 551 and a power feeding coil 552. The power supply unit 155 supplies power to the first axis motor 151 and the like in a non-contact manner by electromagnetic induction. Note that power supply refers to supplying electric power.

The power generating coil 551 is a coil that generates a back electromotive force by electromagnetic induction and can supply power to each of the first axis motor 151, the first axis encoder 531, and the first axis driver board 163. The power supply coil 552 is a coil that is arranged to face the power generation coil 551 and causes the power generation coil 551 to generate a back electromotive force by electromagnetic induction in response to the current flowing from the second axis driver board 173. When a current is passed through the power supply coil 552, a back electromotive force is generated in the power generation coil 551 without contact due to electromagnetic induction.

Although this embodiment exemplifies a configuration in which the power feeding unit 155 performs non-contact power feeding by electromagnetic induction, the present invention is not limited to this. For example, the power feeding unit 155 can also be powered by a rotating contact. A rotating contact is a structure that is electrically connected to a rotating body via a metal ring and a brush placed on the rotating body. Power can also be supplied to the first axis motor 151 and the like from the outside using such a rotating contact.

The substrate 91 is provided with a rotating reflector 5, a first axis motor 151, a first axis encoder 531, a first axis driver board 163, a periodic light emitting section 532, a power generation coil 551, and the like. The rotation stage 10 is provided with a second axis motor 152, a second axis encoder 172, a second axis driver board 173, a periodic light receiving section 533, a power feeding coil 552, and the like.

The first axis motor 151 rotates the rotary reflector 5 around the first axis A1. A DC (Direct Current) motor, an AC (Alternating Current) motor, or the like can be applied to the first axis motor 151.

The first axis encoder 531 outputs a first angle detection signal En1. The first axis encoder 531 is, for example, a rotary encoder.

The first axis driver board 163 is a board that includes an electric circuit that supplies a drive signal to the first axis motor 151, and the like. The first axis driver board 163 can control the rotating reflector 5 to rotate at a predetermined first frequency (rotation speed) based on the first angle detection signal En1. Note that since the first frequency is controlled by the first axis driver board 163, it is not controlled by the rotation control unit 402.

The first axis driver board 163 causes the first axis motor 151 to start rotating the rotary reflector 5 when power supply by the power supply unit 155 is started, and when the power supply by the power supply unit 155 is stopped, the first axis The rotation of the rotary reflector 5 is stopped by the shaft motor 151.

The second axis motor 152 can be configured with various motors such as a DC motor, an AC motor, or a stepping motor. The second axis encoder 172 is composed of a rotary encoder or the like, and detects the rotation angle of the rotation stage 10.

The second axis driver board 173 is a mounting board that includes an electric circuit that supplies a drive signal to the second axis motor 152, and the like. The second axis driver board 173 rotates the rotation stage 10 based on the second axis control signal Dr2 from the rotation control section 402. Further, the second axis driver board 173 outputs the second angle detection signal En2 of the rotation stage 10 detected by the second axis encoder 172 to the rotation control unit 402.

The rotation control unit 402 controls the rotation of the rotation stage 10 based on the second angle detection signal En2. Here, the second frequency, which is the number of rotations of the rotation stage 10, is controlled by the rotation control unit 402.

The light receiving/emitting section 110 includes a light emitting section substrate 111 , a light emitting block 112 , a perforated mirror 6 , a perforated mirror holder 62 , a light receiving block 113 , and a light receiving section substrate 114 .

The light emitting unit substrate 111 is a mounting board that includes an electric circuit that causes the light emitting unit 3 to emit light in response to a light emission control signal Dr1 from the control unit 140.

The light emitting block 112 includes a light emitting section 3, a light emitting section holder 31, a first lens 4, and a first lens holder 40. The light emitting unit holder 31 is a member that holds the light emitting unit 3. The first lens holder 40 is a member that holds the first lens 4. The perforated mirror holder 62 is a member that holds the perforated mirror 6.

The light receiving block 113 includes a second lens 7 , a second lens holder 71 , five light receiving sections 8 , and a light receiving section holder 80 . The second lens holder 71 is a member that holds the second lens 7. The light receiving unit holder 80 is a member that holds five light receiving units 8.

The light receiving unit board 114 is a mounting board that includes an electric circuit that outputs the light receiving information S to the control unit 140. The light reception information S is, for example, an electrical signal according to the intensity of light received by the light receiving section 8. The light receiving unit board 114 includes a transimpedance amplifier, an operational amplifier, and the like. The light receiving unit board 114 can amplify the received light information S using a transimpedance amplifier, an operational amplifier, or the like, so that the received light information S can be put into a state in which data processing by the control unit 140 at the subsequent stage is possible.

The control unit 140 includes a control circuit board having an electric circuit or an electronic circuit. The control unit 140 is installed, for example, on the back panel 22 or the like. This control circuit board does not move even if the rotating reflector 5 and the rotating stage 10 rotate.

The control unit 140 is electrically connected to each of the light receiving/emitting unit 110 and the irradiating unit 120, and is capable of mutually transmitting and receiving signals and data. Further, the control unit 140 is communicably connected to an external device 300 that can control the service robot. In this embodiment, the rotation control unit 402 is provided within the control unit 140, but may be provided outside the control unit 140.

The control unit 140 outputs a light emission control signal Dr1 in response to a ranging control signal Ct from the external device 300, for example, and causes the light emission unit 3 to emit light via the light emission unit substrate 111. The five scanning lights L2, each of which is scanned by the five divided lights L1, pass through the exit window 130 and are irradiated outward from the distance measuring device 100.

The exit window 130 is configured to include a glass material or a resin material that is transparent to the wavelength of the laser beam L0. The exit window 130 functions as a window that transmits and outputs the scanning light L2 when the distance measuring device 100 includes an opaque exterior cover that covers the entire device.

Five return lights R obtained by reflecting or scattering the scanning light L2 by the object 200 pass through the exit window 130 and enter the light reflecting surface 51 of the rotary reflector 5. The five returned lights R are reflected by the light reflecting surface 51 and reflected by the mirror surface of the perforated mirror 6 toward the five light receiving sections 8 .

The five returned lights R enter each of the five light receiving sections 8 while being focused by the second lens 7 . The five light receiving sections 8 output light reception information S for each scanning angle of the five scanning lights L2 based on the five return lights R. The five pieces of light reception information S corresponding to the five scanning lights L2 are output to the control unit 140 via the light reception unit board 114.

The control unit 140 calculates distance information Dt indicating the distance to the object 200 based on the light reception information S. Control unit 140 outputs distance information Dt to external device 300.

The distance measuring device 100 is driven by, for example, electric power supplied from a battery mounted on a service robot. However, the distance measuring device 100 may be supplied with power from a battery mounted on the distance measuring device 100 itself. Furthermore, in cases where the service robot has a limited range of motion, power may be supplied from a commercial power source using a cable.

(Example of light division by light division member 41)
FIG. 5 is a diagram showing an example of light division by the light division member 41. 5(a) is a side view of the light splitting member 41, FIG. 5(b) is a perspective view of the light splitting member 41 seen from the -Z direction side, and FIG. 5(c) is a side view of the light splitting member 41 seen from the +Z direction side. FIG.

The light splitting member 41 is a flat member that has a substantially circular shape in plan view and is transparent to the wavelength of the laser beam L0. A periodic structure is formed on the -Z direction side surface of the light splitting member 41, the +Z direction side surface, or both. The light splitting member 41 splits the incident laser beam L0 into a plurality of light beams by diffracting it using a periodic structure.

The light dividing member 41 divides the laser beam L0 into five divided beams L1 including divided beams L11 to L15. The split light L11 is zero-order light (transmitted light) of the light splitting member 41. The divided lights L12 to L15 are first-order diffracted lights.

The divided lights L11 to L15 are parallel light beams with mutually different propagation directions. The divided lights L11 to L15 are scanned by the irradiation unit 120. The five scanning lights L2 that form pairs with each of the split lights L11 to L15 are irradiated to different positions in the irradiation area, respectively.

The division angle information θL by the light division member 41 shown in FIG. 5(a) may be 2.1 degrees or more. The division angle information θL refers to the angle formed by the center axes of each of the five divided lights L1 divided by the light division member 41 along the propagation direction. When a diffraction grating is used as the light splitting member 41, the splitting angle information θL corresponds to a diffraction angle that is an angle between central axes of light diffracted by the diffraction grating along the propagation direction.

Here, the standard IEC60825-1 defines safety against laser light based on the light intensity detected by a sensor having a light-receiving surface of 7 mm in diameter at a position 100 mm away from a device that emits laser light. When the division angle information θL is 2.1 degrees or more, three or less of the five divided lights L1 divided by the light splitting member 41 enter the light-receiving surface with a diameter of 7 mm located 100 mm away from the distance measuring device 100. be in a state of doing so. This makes it easier for the distance measuring device 100 to comply with the regulations of IEC60825-1.

Based on the pupil diameter and focal length of the human eye, the angle at which three of the five divided lights L1 aligned on the same straight line can enter the human eye in parallel is an angle smaller than ±2.0 degrees. It is. In this embodiment, by setting the division angle information θL by the light splitting member 41 to 2.1 degrees or more, three or more of the five divided lights L1 on the same straight line enter the human eye in parallel. It is possible to realize eye-safety, which means safety for human eyes. Further, in this embodiment, by making the division angle information θL as small as possible at 2.1 degrees or more, it is possible to improve the spatial resolution of distance measurement while realizing eye safety.

In this embodiment, the shape of the light splitting member 41 in plan view is not limited to a circular shape, but may be a rectangular shape, an elliptical shape, a polygonal shape, or the like. In addition, although the configuration in which the divided light L15 is obtained from the divided light L11 that passes through the center of the light splitting member 41 and the divided light L12 that is divided into four diagonal directions is illustrated, the direction in which the laser beam L0 is divided is It is not limited to the diagonal direction, and can be selected as appropriate.

(Example of configuration of synchronization detection unit 153)
FIG. 6 is a diagram illustrating the configuration of the synchronization detection section 153. FIG. 6 schematically shows the rotary stage 10 cut along the YZ plane.

As shown in FIG. 6, the rotation stage 10 includes a rotatable rotating part 10a and a non-rotating fixed part 10b. The periodic light emitting section 532 is mounted on a light emitting substrate 532a provided on the mounting surface 101 of the rotating section 10a. The periodic light receiving section 533 is mounted on a light receiving board 533a provided on the fixed section 10b.

The periodic light emitting section 532 emits pulsed light Op toward the periodic light receiving section 533 disposed opposite to the periodic light emitting section 532 in accordance with the first angle detection signal En1 input to the light emitting board 532a. The light reception signal of the pulsed light Op by the periodic light receiver 533 is converted into a binary signal by the light receiver board 533a, and is output to the rotation controller 402 as a synchronization signal Sn.

(Effects of first lens 4 and second lens 7)
In the distance measuring device 100, the amount of light that returns within the effective diameter of the second lens, out of the return light R of the scanning light L2 from the object 200, is determined according to the spread angle of the scanning light L2 by the first lens 4 shown in FIG. (hereinafter referred to as the amount of returned light) and the amount of light that can be received by the light receiving section 8 (hereinafter referred to as the amount of received light) change. In addition, depending on the specifications of the second lens 7 shown in FIG. The amount of light reaching the target changes, and the amount of returned light and the amount of received light change. In addition, compared to the amount of return light R and the amount of received light from the object 200 that is close to the distance measuring device 100, the object 200 is far away from the distance measuring device 100, for example, at a predetermined maximum measurable distance. The amount of returned light R from the object 200 located at a distance Lx (hereinafter referred to as maximum distance Lx) and the amount of received light are smaller.

In this embodiment, the action of the first lens 4 and the second lens 7 widens the distance range of the object 200 that can ensure a high amount of received light relative to the amount of returned light R. Thereby, in this embodiment, it is possible to ensure a wide range of distances that can be measured by the distance measuring device 100.

First, the function of the first lens 4 will be explained. FIG. 7 is a diagram illustrating the irradiation of the scanning light L2 in the distance measuring device 100.

As shown in FIG. 7, in this embodiment, the spread angle β by the first lens 4 in the distance measuring device 100 is defined so that the diameter Dx of the scanning light L2 becomes small at a position separated by the maximum measurable distance Lx. do. The spread angle β caused by the first lens 4 can be defined, for example, by selecting the focal length of the first lens 4.

Since there is a limit to the distance between the object 200 and the object 200 that can be measured by the distance measuring device 100, the maximum measurable distance Lx is determined in advance according to, for example, the specifications or uses of the distance measuring device 100. The maximum distance Lx is, for example, 30 m.

In this embodiment, by defining the spread angle β of the scanning light L2 by the first lens 4, it is possible to increase the amount of return light R from the object 200 located at a maximum distance Lx away.

Next, the action of the second lens 7 will be explained.

First, the action of the second lens according to the comparative example will be explained. FIG. 8 is a diagram illustrating the relationship between the distance to an object and the diameter of the returned light at the position of the light receiving unit according to a comparative example. In the comparative example, the specifications and focus adjustment state of the second lens are determined so that the diameter of the return light R from the object located at the maximum distance Lx is minimized on the light receiving section 8X. Note that the light receiving section 8X has the same function as the light receiving section 8 according to the embodiment.

The horizontal axis shown in the upper part of FIG. 8 represents the distance from the distance measuring device. On the horizontal axis, the farther you go in the direction of the arrow, the longer the distance becomes. Distance 0 is the distance corresponding to the position of the distance measuring device. The maximum distance Lx is the longest distance that can be measured by the distance measuring device.

The diagram shown in the lower part of FIG. 8 shows five return lights R corresponding to each of the five light receiving sections 8X. Return light Rx is return light from an object located at the maximum distance Lx. Return light R2 is return light from an object located at distance L2X. Return light R1 is return light from an object located at distance L1X. Return light R0 is return light from an object located at a distance of 0. The length relationship between each distance is Lx>L2>L1>0. Further, the relationship between the amount of returned light is Rx<R2<R1<R0.

The focus of the second lens is adjusted so that the diameter of the return light Rx is the smallest compared to the diameters of the other return light R2, return light R1, and return light R0. In other words, the returned light Rx is most focused at the position of the light receiving section 8X compared to other returned lights. Since the diameter of one returned light Rx is smaller than the diameter of one light receiving section 8X, one light receiving section 8X can receive almost the entire amount of one returned light Rx. As a result, a larger proportion of the amount of the returned light Rx can be captured in the light receiving section 8 compared to the amounts of the other returned light R2, returned light R1, and returned light R0.

At the position of the distance L2X, one return light R2 spreads out more than the return light Rx as the distance decreases. However, since the diameter of one returned light R2 is approximately the same as the diameter of one light receiving section 8X, one light receiving section 8X can receive almost all of the amount of one returned light R2. As a result, the rate of reception of the return light R2 becomes as large as the rate of reception of the return light Rx.

At the position of the distance L1X, one returning light R1 spreads out more than the returning light R2 as the distance decreases. The diameter of one returned light R1 is larger than the diameter of one light receiving section 8X. Therefore, one light receiving section 8X can receive the returning light R1 that has reached the light receiving surface of the light receiving section 8X out of one returning light R1, and can receive the returning light R1 that has not reached the light receiving surface of the light receiving section 8X. Return light R1 that protrudes from portion 8X cannot be received. As a result, the rate of reception of the return light R1 becomes smaller than the rate of reception of each of the return light Rx and the return light R2.

At the position where the distance is 0, one returning light R0 spreads out more than the returning light R1 as the distance decreases. The diameter of one return light R0 is larger than the diameter of one return light R1. As a result, the rate of reception of the return light R0 becomes smaller than the rate of reception of the return light R1.

At the position of distance 0, the return light R0 corresponding to the adjacent light receiving section 8X reaches one light receiving section 8X. This causes crosstalk, which is a phenomenon in which a plurality of returned lights R0 are received by one light receiving section 8X. In FIG. 8, a plurality of crosstalk regions Cr represent regions where a plurality of return lights R0 overlap on one light receiving section 8X due to crosstalk. Crosstalk reduces the accuracy of distance measurement by a distance measuring device.

In the range QX3 indicated by the white arrow in the upper part of FIG. 8, almost all of one return light R can be received by one light receiving section 8X, so that it is possible to ensure high distance measurement accuracy by the distance measuring device.

In range QX2, as the proportion of return light R received by one light receiving section 8X decreases, the proportion of light received by the distance measuring device decreases compared to range QX3. However, since the distance is short compared to range QX3, the absolute amount of return light R is large, so the effect of decrease in distance measurement accuracy is small, and in range QX2, crosstalk does not occur, so There is no reduction in distance measurement accuracy due to talk.

In range QX1, as the amount of return light R received by one light receiving unit 8X decreases, the proportion of light received by the distance measuring device decreases compared to range QX2. However, since the distance is short compared to range QX2, the absolute amount of returned light R is large, so the effect of decrease in ranging accuracy is small; however, in range QX1, crosstalk occurs, so the Distance measurement accuracy due to talk decreases.

In the comparative example, the measurement range in which the distance measurement accuracy of the distance measuring device can be ensured at a high level by ensuring a high reception ratio of the returned light R corresponds to the range QX3.

In the comparative example, the measurement range that can ensure high distance measurement accuracy by the distance measuring device by suppressing crosstalk between the plurality of return lights R corresponds to the sum of the range QX3 and the range QX2.

Next, the action of the second lens 7 according to this embodiment will be explained. In this embodiment, when the focal length of the second lens 7 is f and the effective diameter of one light receiving section 8 is d, the second lens 7 satisfies the following formula (1).

Furthermore, in the present embodiment, when the effective diameter of the second lens 7 is φ, the image formed by the second lens 7 is located at a first distance La expressed by the following equations (2) and (3). The object is in focus. Here, the object located at the first distance La means an object whose portion of the object closest to the distance measuring device is located at the first distance La.

FIG. 9 is a diagram illustrating the relationship between the distance to an object and the diameter of the return light R at the position of the light receiving section 8 according to the present embodiment.

The horizontal axis shown in the upper part of FIG. 9 represents the distance from the distance measuring device. On the horizontal axis, the farther you go in the direction of the arrow, the longer the distance becomes. Distance 0 is a distance corresponding to the position of the distance measuring device. The maximum distance Lx is the longest distance that can be measured by the distance measuring device.

The diagram shown in the lower part of FIG. 9 shows five return lights R corresponding to the five light receiving sections 8, respectively. Return light Rx is return light from an object located at the maximum distance Lx. Return light Ra is return light from an object located at a first distance La. Return light Rb is return light from an object located at the second distance Lb. Return light Rc is return light from an object located at the third distance Lc. Return light R0 is return light from an object located at a distance of 0. The length relationship between each distance is Lx>La>Lb>Lc>0. Further, the relationship between the amount of returned light is Rx<Ra<Rb<Rc<R0.

The diameter of one returned light Rx is approximately the same as the diameter of one light receiving section 8. One light receiving section 8 is capable of receiving almost the entire amount of one return light Rx. As a result, a larger proportion of the received light amount of one returned light Rx is captured in the light receiving unit 8 than that of the other returned light Rb, returned light Rc, and returned light R0.

At the position of the first distance La, one returning light Ra is more focused than one returning light Rx as the distance is shortened. The diameter of one return light Ra is the smallest compared to the diameters of the other return light Rx, return light Rb, return light Rc, and return light R0. In other words, the returned light Ra is most focused at the position of the light receiving section 8 compared to other returned lights. Since the diameter of one returned light Ra is smaller than the diameter of one light receiving section 8, one light receiving section 8 can receive almost the entire amount of one returned light Ra. As a result, the amount of received return light Ra becomes as large as the amount of received return light Rx.

At the position of the second distance Lb, one return light Rb spreads out more than the return light Ra as the distance decreases. The diameter of one returned light Rb is approximately the same as the diameter of the light receiving section 8. One light receiving section 8 is capable of receiving almost the entire amount of one return light Rb. As a result, the rate of reception of the return light Rb becomes as large as the rate of reception of the return light Ra.

At the position of the third distance Lc, one returning light Rc spreads out more than the returning light Rb as the distance decreases. The diameter of one returned light Rc is larger than the diameter of one light receiving section 8. Therefore, one light receiving section 8 can receive the returning light Rc that has reached the light receiving surface of the light receiving section 8 out of one returning light Rc, and can receive the returning light Rc that has not reached the light receiving surface of the light receiving section 8. The return light Rc protruding from the portion 8 cannot be received. As a result, the rate of reception of the return light Rc becomes smaller compared to the rate of reception of each of the other return light Rx, return light Ra, and return light Rb.

At the position where the distance is 0, one returning light R0 spreads out more than the returning light Rc as the distance decreases. The diameter of one return light R0 is larger than the diameter of one return light Rc. As a result, the rate of reception of the return light R0 becomes smaller than the rate of reception of the return light Rc.

At the position of distance 0, the return light R0 corresponding to the adjacent light receiving section 8 reaches one light receiving section 8, and crosstalk occurs. A plurality of crosstalk regions Cr in FIG. 9 represent regions where a plurality of return lights R0 overlap on one light receiving section 8 due to crosstalk.

In the present embodiment, the measurement range in which distance measurement accuracy can be ensured by ensuring a high amount of received return light R corresponds to range Q3. Range Q3 is wider than range QX3 according to the comparative example.

In this embodiment, the measurement range in which high distance measurement accuracy can be ensured by suppressing crosstalk between the plurality of return lights R corresponds to the sum of the range Q3 and the range Q2. The sum of range Q3 and range Q2 is wider than the sum of range QX3 and range QX2 according to the comparative example.

For example, if the maximum distance Lx is set to 30 m and the focus distance, which means the distance to the object that is to be brought into focus during imaging by the second lens 7, is 5 m, then the range Q3 is from 30 m to 1. The range can be up to 5m. Moreover, the range Q2 can be set to a range from 1.5 m to 0.6 m.

In a distance measuring device, it is impossible to ensure a high reception ratio of returned light and to prevent crosstalk in all ranges from long distances to short distances to objects. Even if an object located at a predetermined distance is focused in imaging by the second lens, if the distance between the object and the object deviates from the predetermined distance, the returned light will spread and the proportion of returned light received will decrease. This is because crosstalk also occurs.

In this embodiment, the first lens 4 defines the spread angle β of the scanning light L2, thereby increasing the amount of return light R from an object located at a maximum distance Lx away. As a result, it is possible to increase the amount of return light R and the amount of received light from an object located at a maximum distance Lx away. It is possible to ensure the accuracy of distance measurement of an object at a certain position. In order to enable a distance measuring device to measure distances to objects with low reflectance, it is important to ensure the amount of light received at long distances.

In the present embodiment, the second lens 7 satisfies the above formula (1), thereby widening the range Q3 in which the light receiving portion 8 can receive a large proportion of light, thereby ensuring a wide measurable distance range. be able to. Furthermore, in the present embodiment, by satisfying the above equation (1) and narrowing the range Q1 in which crosstalk occurs, it is possible to ensure a wide range of measurable distances.

In this embodiment, in the image formation by the second lens 7, the object located at the first distance La expressed by the above equations (2) and (3) is focused. As a result, it is possible to widen the range Q3 in which the amount of light received by the light receiving unit 8 can be ensured, and also to suppress crosstalk between the plurality of return lights R, and to ensure a wide range of measurable distances. .

Further, in the present embodiment, in the image formation by the second lens 7, the second distance Lb expressed by the following equation (4) is such that the diameter of the return light Rb shown in FIG. 9 is approximately equal to the diameter of the light receiving part 8. The distance becomes

Furthermore, in this embodiment, when the interval between adjacent light receiving parts 8 among the plurality of light receiving parts 8 is p, and the diffraction angle by the light splitting member 41 is γ, the following equation ( 5), the third distance Lc expressed by equations (6) and (7) is the distance at which crosstalk does not occur as shown in FIG.

Note that FIG. 10 is a diagram illustrating the distance p between adjacent light receiving sections 8. In FIG. The interval p is the interval between the centers of adjacent light receiving sections 8. The distance p is the closest distance between adjacent light receiving sections 8. The plurality of light receiving sections 8 may be arranged in any desired arrangement.

(Example of hardware configuration of control unit 140)
FIG. 11 is a block diagram illustrating the hardware configuration of the control unit 140. The control unit 140 is constructed by a computer, and includes a CPU (Central Processing Unit) 141, a ROM (Read Only Memory) 142, a RAM (Random Access Memory) 143, an FPGA (Field Programmable Gate Array) 144, and an HDD. /SSD (Hard Disk Drive/Solid State Drive) 145, device connection I/F (Interface) 146, and communication I/F 147. These are connected to each other via a system bus A so that they can communicate with each other.

The CPU 141 and the FPGA 144 execute control processing including arithmetic processing. The ROM 142 stores programs used to drive the CPU 141, such as IPL (Initial Program Loader). RAM 143 is used as a work area for CPU 141. The HDD/SSD 145 stores various information such as programs and setting information of the distance measuring device 100.

The device connection I/F 146 is an interface for connecting the control unit 140 to devices. The devices here include a light emitting unit board 111, a light receiving unit board 114, a synchronization detection unit 153, a power supply unit 155, a second axis encoder 172, a second axis driver board 173, and the like.

The communication I/F 147 is an interface for communicating data with the external device 300, a communication network, and the like. As the communication I/F 147, an Ethernet interface or the like can be applied. The control unit 140 can also connect to the Internet via the communication I/F 147 and communicate with the external device 300 via the Internet.

(Example of functional configuration of control unit 140)
FIG. 12 is a block diagram illustrating an example of the functional configuration of the control unit 140. The control section 140 includes a variable section 401, a rotation control section 402, a light emission control section 403, a distance information acquisition section 404, and an output section 405. The rotation control section 402 includes a first axis rotation control section 421, a second axis rotation control section 422, and a stop control section 423.

The control unit 140 can realize each function of the variable unit 401, the rotation control unit 402, the light emission control unit 403, and the distance information acquisition unit 404 by using the FPGA 144 or the like, and can also realize at least a part of each of the above functions by the CPU 141. . Further, the control unit 140 can implement the functions of the output unit 405 using the communication I/F 147 or the like.

Each function realized by the FPGA 144 or the like may be realized by a plurality of circuits or a plurality of software. Further, a part of each function realized by the FPGA 144 etc. may be realized by a component other than the control unit 140 such as the external device 300, or distributed processing between the control unit 140 and a component other than the control unit 140. It may be realized by

The variable unit 401 changes the second frequency fh of the rotation stage 10 by changing the constant α in the following equations (1) and (2).
fh=M×fv/(N+α)...(1)
0<|α|<1...(2)
In Equation (1), N represents the number of scanning lines formed by the five scanning lights L2 scanned in a direction intersecting the first axis A1 during one rotation of the rotation stage 10. fv represents the first frequency. M represents the number of scanning lines formed by the five scanning lights L2 scanned in the first direction during one rotation period of the rotating reflector 5. In the case of an m-plane rotating reflector 5, M=m. When a swinging mirror (reciprocating mirror) is used instead of the rotating reflector 5, M=2.

The variable unit 401 can change the constant α in accordance with setting input information Se from the outside, such as an operation unit provided in the distance measuring device 100.

The first axis rotation control unit 421 outputs a power supply control signal St to the power supply unit 155 and causes the power supply unit 155 to start supplying power to the first axis motor 151, thereby causing the first axis motor 151 to start rotating. Further, the first axis rotation control unit 421 outputs a power supply control signal St to the power supply unit 155 and stops the power supply from the power supply unit 155 to the first axis motor 151, thereby causing the first axis motor 151 to stop rotating. . The first axis rotation control unit 421 controls only the start and stop of rotation of the first axis motor 151, and does not control the rotation speed of the first axis motor 151.

The second axis rotation control unit 422 controls the rotation stage 10 using the second axis driver board 173 based on the synchronization signal Sn from the synchronization detection unit 153 and the second angle detection signal En2 from the second axis encoder 172. control the rotation of

The stop control unit 423 stops the rotation of the rotary stage 10 by the second axis motor 152 when the synchronization signal Sn is not output from the synchronization detection unit 153 for a predetermined period.

The light emission control section 403 controls the light emission of the light emitting section 3 by outputting a light emission control signal Dr1 to the light emitting section 3 using the light emitting section substrate 111. Further, the light emission control unit 403 outputs light emission time information t1 corresponding to the time when the light emission unit 3 emits light to the distance information acquisition unit 404.

The distance information acquisition unit 404 calculates distance information Dt between the object 200 and the object 200 based on the five return lights R received by the five light receivers 8 after the scanning light L2 is reflected or scattered by the object 200. Obtained by The distance information acquisition unit 404 inputs light emission time information t1 at which the laser beam L0 was emitted by the light emitting unit 3 from the light emission control unit 403. Further, the distance information acquisition unit 404 inputs five light reception information S corresponding to the five light reception units 8 from the five light reception units 8 via the light reception unit board 114, and receives five light reception information S corresponding to the five light reception units 8 based on the five light reception information S. Obtain time information t2. The distance information acquisition unit 404 can acquire the distance information Dt by calculating the following equation (3) based on the principle of TOF.
Dtn=c×Δtn/2 (3)

In formula (3), n is a natural number corresponding to each of the divided lights L11 to L15. For example, Dt1 is distance information obtained based on divided light L11, Dt2 is distance information obtained based on divided light L12, Dt3 is distance information obtained based on divided light L13, Dt4 is distance information obtained based on divided light L14, Dt5 is distance information obtained based on the divided light L15. c represents the speed of light (approximately 3×10 ⁸ m/s). The distance information Dt is a generic notation for a plurality of distance information Dtn. Δt is the time difference between the light emission time and light reception time of each of the divided lights L11 to L15.

Since the divided lights L11 to L15 are obtained by dividing the laser beam L0 emitted simultaneously from the light emitting section 3, the light emission times are the same. On the other hand, the reception times of the five return lights R based on the split lights L11 to L15 are different. The distance information acquisition unit 404 acquires distance information Dtn based on each of the divided lights L11 to L15 in parallel by calculation.

The output unit 405 outputs to the external device 300 five pieces of distance information Dt to the object acquired based on the five pieces of light reception information S by the five light receivers 8 .

The distance measuring method used by the distance measuring device 100 is not limited to the TOF method. For example, the distance measuring device 100 uses a phase difference detection method that irradiates an object with amplitude-modulated laser light and obtains distance information based on the phase difference between the returned light reflected or scattered by the object and the irradiated laser light. May be used.

<Example of processing by control unit 140>
FIG. 13 is a flowchart illustrating an example of processing by the control unit 140. The control unit 140 starts the process shown in FIG. 13 at the timing when the distance measuring device 100 is powered on and the distance measuring device 100 is activated.

First, in step S141, the control unit 140 determines whether the variable unit 401 changes the scanning line interval or the refresh rate. For example, the variable unit 401 can determine whether to change the scan line interval or the refresh rate based on a setting input by the operator of the distance measurement device 100 using the operation unit of the distance measurement device 100.

If it is determined in step S141 that there is no change (step S141, NO), the control unit 140 moves the process to step S144. On the other hand, if it is determined to change (step S141, YES), the control unit 140 receives the setting input information Se through the variable unit 401 in step S142.

Subsequently, in step S143, the control unit 140 changes the constant α using the variable unit 401 according to the setting input information Se. As a result, the second frequency fh changes according to the above equation (1), and the scanning line interval and refresh rate are changed.

Subsequently, in step S144, the control unit 140 causes the first axis rotation control unit 421 to start feeding power from the power supply unit 155 to the first axis motor 151. The first axis motor 151 starts rotating in response to the start of power feeding by the power feeding section 155, thereby starting the rotation of the rotary reflector 5.

Subsequently, in step S145, the control unit 140 causes the second axis rotation control unit 422 to, based on the synchronization signal Sn from the synchronization detection unit 153 and the second angle detection signal En2 from the second axis encoder 172, Rotation of the rotation stage 10 is started. Thereafter, the rotation stage 10 continues to rotate under the control of the second axis rotation control section 422.

Subsequently, in step S146, the control unit 140 causes the light emitting unit 3 to emit the laser beam L0 by outputting the light emission control signal Dr1 to the light emitting unit 3 using the light emission control unit 403. The light emission control unit 403 also outputs light emission time information t1 of the light emission unit 3 to the distance information acquisition unit 404.

Subsequently, in step S147, the control unit 140 inputs five light reception information S output from the five light receiving units 8 based on the return light R derived from the five scanning lights L2.

Subsequently, in step S148, the control unit 140 causes the distance information acquisition unit 404 to obtain distance information Dt based on the light reception time information t2 of the return light R based on the light reception information S and the light emission time information t1 of the light emission unit 3. is obtained by calculation.

Subsequently, in step S149, the control unit 140 outputs the distance information Dt to the external device 300 using the output unit 405.

Subsequently, in step S140, the control unit 140 uses the stop control unit 423 to determine whether the period during which the synchronization signal Sn from the synchronization detection unit 153 is not output is equal to or less than a predetermined period threshold.

If it is determined in step S140 that the period is not equal to or less than the period threshold (step S140, NO), the control unit 140 moves the process to step S142. On the other hand, if it is determined that the period is equal to or less than the period threshold (step S140, YES), the control unit 140 determines in step S141 whether to end distance measurement by the distance measurement device 100. For example, the control unit 140 can determine whether to end distance measurement based on an operation input by an operator using the operation unit of the distance measurement device 100.

If it is determined in step S141 that the process does not end (step S141, NO), the control unit 140 performs the processes from step S146 onwards again. On the other hand, if it is determined to end (step S141, YES), in step S142, the control unit 140 causes the second axis rotation control unit 422 to stop the rotation of the rotation stage 10, and causes the light emission control unit 403 to stop the rotation of the rotation stage 10, and causes the light emission control unit 403 to Stop the light emission of step 3.

Subsequently, in step S143, the control unit 140 causes the first axis rotation control unit 421 to stop the power supply from the power supply unit 155 to the first axis motor 151, thereby causing the first axis motor 151 to stop rotating. The first axis motor 151 stops rotating in response to the stop of power supply by the power supply unit 155, and stops the rotation of the rotating reflector 5.

As described above, the control unit 140 can control the distance measuring operation by the distance measuring device 100.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to these embodiments, and various modifications or variations can be made within the scope of the gist of the present invention as described in the claims. Changes are possible.

All numbers such as ordinal numbers and quantities used in the description of the embodiments are exemplified to concretely explain the technology of the present invention, and the present invention is not limited to the illustrated numbers. Further, the connection relationships between the constituent elements are provided as examples to specifically explain the technology of the present invention, and the connection relationships for realizing the functions of the present invention are not limited to these.

The distance measuring device and the ranging system according to the embodiments are mounted on not only service robots but also moving bodies such as automobiles and flying bodies, and can be used in applications such as recognizing objects existing around the moving body.

DESCRIPTION OF SYMBOLS 1... Stand part, 2... Holding part, 3... Light emitting part, 4... First lens, 5... Rotating reflector, 6... Hole mirror, 7... Second lens, 8... Five light receiving parts, 81, 82, 83, 84, 85... Light receiving part, 9... Tombstone, 10... Rotating stage, 10a... Rotating part, 10b... Fixing part, 11... Coupling member, 21... Ceiling panel, 22... Back panel, 31... Light emitting part holder, 40 ...First lens holder, 41...Light dividing member, 51...Light reflecting surface, 61...Through hole, 62...Perforated mirror holder, 71...Second lens holder, 90...First direction, 91...Substrate, 100...Measurement Distance device, 101... Placement surface, 102... Bearing, 103... Magnet, 104... Motor core, 110... Light receiving/emitting section, 112... Light emitting block, 113... Light receiving block, 114... Light receiving section substrate, 120... Irradiating section, 130... Output window, 140... Control section, 401... Variable section, 402... Rotation control section, 403... Light emission control section, 404... Distance information acquisition section, 405... Output section, 421... First axis rotation control section, 422... Second Axis rotation control unit, 423... Stop control unit, 150... Drive control unit, 151... First axis motor, 152... Second axis motor, 153... Synchronization detection unit, 155... Power supply unit, 163... First axis driver board, 172... Second axis encoder, 173... Second axis driver board, 200... Object, 300... External device, 531... First axis encoder, 532... Periodic light emitting section, 532a... Light emitting board, 533... Periodic light receiving section, 533a... Light receiving board, 551... Power generation coil, 552... Power feeding coil, A1... First axis, A11... First axis rotation direction, A2... Second axis, A21... Second axis rotation direction, L0... Laser light, L1, L11, L12, L13, L14, L15...Split light, L2...Scanning light, R, Rx, Ra, Rb, Rc, R0...Return light, Dr1...Light emission control signal, Dr2...Second axis control signal, Ct...Measurement Distance control signal, Dt...Distance information, S...Light reception information, Sn...Synchronization signal, St...Power supply control signal, En1...First angle detection signal, En2...Second angle detection signal, Op...Pulsed light, Lx...Maximum distance , Dx...diameter, β...spread angle, La...first distance, Lb...second distance, Lc...third distance, Cr...crosstalk area, p...interval

Claims (5)

A distance measuring device that measures the distance to an object,
a first lens that transmits light from the light emitting section;
an irradiation unit that irradiates the object with the light that has passed through the first lens;
a second lens that transmits return light that is light from the irradiation unit that is reflected or scattered by the object;
a light receiving unit that outputs received light information based on the returned light that has passed through the second lens;
an output unit that outputs distance information to the object based on the light reception information from the light reception unit,
The first lens adjusts the spread angle of the light from the light emitting section so that the diameter of the light irradiated by the irradiation section is minimized at a position of the object that is a predetermined maximum measurable distance away. Define β,
In the distance measuring device, the second lens satisfies the following formula (1), where f is the focal length of the second lens and d is the effective diameter of one of the light receiving sections.

When the effective diameter of the second lens is φ, in imaging by the second lens, the focus is on the object located at a first distance La expressed by the following equations (2) and (3). The distance measuring device according to claim 1, which matches the distance measuring device.

a light splitting member that splits the light transmitted through the first lens into a plurality of parts;
The irradiation unit irradiates the object with a plurality of lights divided by the light splitting member,
The light receiving section includes a plurality of light receiving sections that are paired with each of the plurality of lights split by the light splitting member, and based on the plurality of return lights that have passed through the second lens, each of the plurality of light receiving sections The distance measuring device according to claim 2, wherein the distance measuring device outputs the light reception information according to the method. The light splitting member is a diffraction grating,
Assuming that the interval between adjacent light receiving parts among the plurality of light receiving parts is p, and the diffraction angle by the diffraction grating is γ, in image formation by the second lens, the following equations (5), (6), and 3. The calculation process of the distance information for the object located further away than the third distance Lc expressed by equation (7) is different from the calculation process of the distance information for the object located at a short distance. The distance measuring device described in .

The distance measuring device according to claim 1 or 2, wherein the irradiation unit irradiates the object with light scanned in at least one direction.

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