JP5533759B2 - Laser radar equipment - Google Patents

Description

  The present invention relates to a laser radar device.

  As a technique for detecting an object using laser light, for example, an apparatus as disclosed in Patent Document 1 is provided. In the apparatus of Patent Document 1, an optical isolator that transmits laser light and reflects reflected light from a detection object toward the detection means is provided on the optical axis of the laser light from the laser light generation means. Furthermore, a concave mirror that rotates about the central axis in the optical axis direction is provided on the optical axis of the laser light that passes through the optical isolator. The concave mirror reflects the laser light toward the space and reflects it from the detection object. Reflecting light toward the optical isolator enables 360 ° horizontal scanning.

  In the technique of Patent Document 1, 360 ° horizontal scanning is possible by rotating the concave mirror, and the detection area (area where scanning with laser light is performed) is expanded to the entire periphery of the apparatus, but the detection area is flat. There is a problem of being limited. That is, since the laser beam reflected toward the space from the concave mirror is scanned within a predetermined plane (scanning plane), the region outside the scanning plane cannot be detected. Therefore, a detected object that deviates from the scanning plane cannot be detected, and even if the detected object exists in the scanning plane, the detected object cannot be grasped in three dimensions.

  As a technique that solves such a problem and enables three-dimensional scanning, a technique such as Patent Document 2 is provided. For example, in the three-dimensional distance measuring device of Patent Document 2, a two-dimensional distance measuring device (100) including a rotating body (8) that rotates about a predetermined rotation axis (P1), and the two-dimensional distance measuring device ( 100) is provided with a second rotation mechanism (20) that rotates around a second axis (P2) that obliquely intersects the first axis (P1). The second rotating mechanism 20 includes a first bracket (22) that swings and supports around a third axis (P3) orthogonal to the second axis (P2), and on the first axis (P1). A rotary arm (24) connected through a free joint mechanism (24) is provided at a predetermined position, and the rotary arm (24) is rotationally driven by a drive mechanism (28), whereby the first axis (P1). The roll angle (α) and the pitch angle (β) are changed, and thereby the two-dimensional distance measuring device (100) is swung to perform three-dimensional scanning.

Japanese Patent No. 2789741 JP 2008-134163 A

  If laser scanning is performed three-dimensionally by the technique as described in Patent Document 2, the laser scanning range limited in the horizontal direction can be expanded in the height direction, and the application and convenience can be greatly improved. . However, when the degree of freedom in scanning in the height direction is increased in this way, a new problem that has not been a problem in horizontal scanning as in Patent Document 1 occurs.

  For example, when an object is detected by placing a laser radar device outdoors or the like, in a horizontal scanning type like Patent Document 1, a position where reflected light is generated (that is, a position where the object is irradiated with laser light). Is limited to the horizontal scanning area, the visual field range in the external space (the range in which light can be received by the light receiving sensor) only needs to be such that reflected light generated on the horizontal scanning area can be detected. Therefore, in general, it is not necessary to set the field of view so wide, and the upper boundary of the field of view does not need to be set so high, so disturbance light (sunlight etc.) from the upper side is a problem. It was hard to become.

  On the other hand, when object detection is performed by three-dimensionally scanning laser light as in Patent Document 2, as the scanning range expands in the vertical direction, the field of view that can receive light is expanded accordingly. I must. However, if the field of view that can be received in this way is widened, disturbance light from the side deviating from the horizontal direction (for example, sunlight from the upper side) is easily received due to the expansion of the field of view. There is concern about becoming.

  For example, when a 3D scan is possible so that the laser beam can be scanned not only in the horizontal direction but also in a higher direction, not only the reflected light returning from the object during the horizontal scan but also the height Even if the scanning level of the direction is the maximum or minimum, the light receiving angle range at the light receiving sensor is set to be somewhat wide so that the reflected light returning from the object can be received, and the field of view range in the external space (light can be received by the light receiving sensor) It is necessary to widen the range. However, when widening the field of view in this way, during horizontal scanning, not only regular reflected light from an object corresponding to laser scanning, but also disturbance light from the upper side unrelated to laser scanning may be captured. , And there is a possibility that regular reflected light and disturbance light cannot be distinguished. In particular, when a laser radar device is placed outdoors and three-dimensional laser scanning is performed, even during horizontal scanning, sunlight that has a large amount of light and has a component with the same wavelength or approximate wavelength as the laser light enters as disturbance light. Thus, there is a greater possibility that accurate object detection is hindered.

  In addition, the above problems are not limited to the case where the laser radar device is placed outdoors, but there is an element that generates disturbance light on the upper side or the lower side that deviates from the horizontal direction (of the laser radar device). A similar problem may occur when there is an illumination light source or the like that can be disturbing light above the installation position.

  The present invention has been made to solve the above-described problems, and in a laser radar device capable of three-dimensional scanning that can irradiate laser light in a direction close to the horizontal direction and a direction deviating from the horizontal direction, An object of the present invention is to provide a configuration capable of effectively suppressing the influence of disturbance light from a direction deviating from the horizontal direction when scanning laser light in a near direction.

In order to achieve the above object, the invention of claim 1
Laser light generating means for generating laser light;
A deflection unit configured to be rotatable about a predetermined central axis; and a driving unit that rotationally drives the deflection unit, and the laser beam generated by the laser beam generation unit while rotating the deflection unit. Rotation deflecting means for deflecting toward the external space by the deflecting unit;
The direction of the laser beam irradiated to the external space through the deflection unit with respect to the horizontal direction is at least as compared with the first direction in which the laser beam is inclined with respect to the horizontal direction and the first direction. And an irradiation direction changing means for changing to a second direction having a small angle between the laser beam and the horizontal direction,
A configuration in which when the laser beam deflected toward the external space by the deflecting unit is reflected by an object existing in the external space, the reflected light from the object is guided along a guide path defined in the apparatus. And guiding means having a condensing part for condensing the reflected light in the middle of the guiding path;
A light receiving means for receiving the reflected light guided by the guiding means;
The external space that can receive light by the light receiving unit by moving at least one of the light collecting unit and the light receiving unit to change a path length from the light collecting unit to the light receiving unit in the guide path. Visual field range changing means for changing the visual field range at
With
The field-of-view range changing means sets the field-of-view range to the first range when the direction of the laser light is set to the first direction by the irradiation direction changing means, and the direction of the laser light is When set in the second direction, the visual field range is set to the second range, and the visual field range is narrower than the first range, so that the visual field range is narrower than the first range. The path length to the light receiving means is adjusted.

According to the first aspect of the present invention, there is provided a visual field range changing means capable of changing the visual field range in the external space that can receive light by the light receiving means, and the visual field range changing means is a path from the light collecting unit to the light receiving means. When the viewing field range is changed by adjusting the length, and the direction of the laser beam is set to the first direction (the direction in which the angle formed with the horizontal direction becomes relatively large) by the irradiation direction changing means, When the visual field range is set to the first range and the direction of the laser beam is set to the second direction (the direction in which the angle formed with the horizontal direction becomes relatively small), the visual field range is narrower than the first range. The second range is set.
In this configuration, when the laser beam is irradiated obliquely upward or obliquely downward (first direction) with a relatively large inclination with respect to the horizontal direction, the viewing field range can be set relatively wide. It becomes easy to receive the regular detection light (reflected light reflected by the object of the irradiated laser beam) returned from the object. Therefore, it is possible to perform laser scanning not only in the vicinity of the horizontal direction but also obliquely upward or obliquely downward (first direction) away from the horizontal direction and object detection in that direction.
On the other hand, when the laser beam is irradiated near the horizontal direction (second direction) with a relatively small inclination with respect to the horizontal direction, the field of view range can be set relatively narrow, so that the laser beam is oriented in the direction near the horizontal direction. When the object is detected by irradiating the light, disturbance light from the upper side or the lower side far away from the irradiation direction of the laser light can be prevented from being received as much as possible. Since the influence of disturbance light can be reliably suppressed in this way, an object detection misjudgment caused by disturbance light (for example, when it is misjudged that an object detection was made due to the influence of disturbance light when no object exists) ) Or detection leakage due to disturbance light (for example, when regular reflected light is generated from an object but this reflected light is drowned out by disturbance light) can be more reliably prevented. The accuracy of object detection can be increased.

In the invention of claim 2, the rotational deflection means is configured as at least a part of the guiding means. Further, the deflecting unit is constituted by a concave mirror. The concave mirror deflects the laser light from the laser light generating means to the external space side and guides the reflected light from the detection object to the light receiving means side. It is configured as follows. The visual field range changing means is configured to change the visual field range in the external space by moving the light receiving means to change the path length from the concave mirror to the light receiving means.
In this way, if a concave mirror having a condensing function is used and the light receiving means is moved so that the path length from the concave mirror to the light receiving means can be changed, a dedicated collection is provided for the path from the concave mirror to the light receiving means. There is no need to provide the light means, or even if it is provided, the size and number can be reduced, the number of parts can be reduced, and the apparatus configuration can be simplified.

In the invention of claim 3, after the direction of the laser beam is switched to the first direction, the irradiation direction changing means maintains the first direction for at least one round of rotation of the deflecting unit and the second direction. After switching, the direction is controlled so as to maintain the deflecting unit in the second direction for at least one rotation. The field-of-view range changing means maintains the field-of-view range in the first range during the rotation in which the direction of the laser light is maintained in the first direction, and the field-of-view range in the rotation in which the direction of the laser light is maintained in the second direction. Is configured to perform path length switching control so as to be maintained in the second range.
In this configuration, after the direction of the laser beam is switched to the first direction, the direction of the field of view is maintained in the first range while the deflection unit is rotated one or more times. Similarly, after the direction of the laser beam is switched to the second direction, the deflection unit is maintained in that direction for one or more rotations, while the visual field range is maintained in the second range. Accordingly, the field-of-view range switching control (that is, the path length switching control) is not repeated many times during one round of the deflection unit, and the electrical and mechanical loads associated with the switching control can be reliably reduced. it can.
Further, according to the above configuration, it is easy to increase the speed of the deflection unit. For example, when the method of switching the field of view multiple times during one round of the deflection unit is used, it is necessary to switch the field of view by a fraction or tens of the period of the deflection unit, which is inexpensive driving Such a high-speed drive is difficult by means. In addition, although it is conceivable to switch the visual field range to a certain degree of speed, such a drive means is expensive, and even if such a drive means is used, the visual field range is switched multiple times during one round. In the method, since it is necessary to make the rotation period of the deflecting unit several times or several tens of times the switching range of the visual field range, it is difficult to increase the speed of the deflecting unit. On the other hand, in the above configuration, since the field-of-view range switching interval can be set longer than the rotation period of the deflecting unit, not only the field-of-view range can be switched at high speed, but also the switching interval is not so short. Even so, it becomes easier to cope with the higher speed of the deflection unit.

In the invention of claim 4, there is provided a setting means for setting a detection area, and the setting means uses a predetermined rotation angle range as a detection range within the entire rotation angle range of the deflecting unit, and is outside the predetermined rotation angle range. The detection area is set to be a non-detection range. The irradiation direction changing means maintains the first direction through the period in which the rotation angle of the deflecting unit is within the detection range after switching the direction of the laser light to the first direction, and after switching to the second direction, The rotation angle of the deflecting unit is maintained in the second direction throughout the period within the detection range. The visual field range changing unit is configured to change the path length from the light collecting unit to the light receiving unit at a timing when the rotation position of the deflecting unit is in the non-detection range.
In this configuration, the visual field range can be efficiently switched using a period in which the rotation angle of the deflection unit is in the non-detection range, and at the time of detection (when the rotation angle of the deflection unit is in the detection range) The direction of the laser beam can be stably maintained in the first direction or the second direction. In addition, since the visual field range is switched once in one or more laps, the electrical and mechanical loads associated with the switching control are reduced compared to the method of switching the visual field range multiple times during one lap. This makes it easy to increase the speed of the deflection unit.

FIG. 1 is a schematic cross-sectional view of a laser radar device according to a first embodiment of the present invention. FIG. 2 is a flowchart illustrating the flow of visual field range switching processing in the laser radar apparatus of FIG. 3A is an explanatory diagram conceptually illustrating the visual field range when the direction of laser light irradiation is set to the first direction in the laser radar apparatus of FIG. 1, and FIG. These are explanatory drawings for conceptually explaining the visual field range when the direction of laser light irradiation is set in the second direction. FIG. 4 is an explanatory diagram for explaining the variable amount of the distance between the light receiving means and the light collecting unit. FIG. 5 is an explanatory diagram for explaining the relationship between the visual field range switched in the external space and the disturbance light generating element. FIG. 6A is a waveform diagram schematically showing an example of a received light waveform when object detection is performed with the first range without switching the visual field range, and FIG. It is a wave form diagram showing roughly an example of a light reception waveform when it switches to 2 ranges and performs object detection. FIG. 7 is a schematic cross-sectional view of a laser radar device according to the second embodiment of the present invention. FIG. 8 is a schematic cross-sectional view schematically showing a configuration in which the laser radar device of FIG. 7 is cut in a direction orthogonal to the central axis. FIG. 9 is an explanatory diagram showing a state after the visual field range is switched from the state of FIG.

[First embodiment]
Hereinafter, a first embodiment embodying the present invention will be described with reference to the drawings.
(Whole structure of laser radar device)
First, the overall configuration of the laser radar apparatus according to the first embodiment will be outlined with reference to FIG. FIG. 1 is a schematic cross-sectional view of the laser radar device according to the first embodiment of the present invention.
As shown in FIG. 1, the laser radar device 1 includes a laser diode 10 and a photodiode 20 that receives reflected light L2 from a detection object, and is configured as a device that detects the distance and direction to the detection object. Yes.

  The laser diode 10 corresponds to an example of “laser light generating means”, and is configured by, for example, a known laser diode. The laser diode 10 is supplied with a pulse current from a drive circuit (not shown) and intermittently projects a pulse laser beam (laser beam L1) at predetermined intervals according to the pulse current.

  The photodiode 20 is formed of a known photodiode such as an avalanche photodiode, for example. When the laser light L1 is generated from the laser diode 10, the reflection of the laser light L1 reflected by an object existing in the external space. The light L2 is received and converted into an electrical signal. In addition, about the reflected light L2 from a detection object, the thing of the visual field range set with the optical system mentioned later is taken in, and the laser beam L1 passes the path | route shown with a continuous line in the example of FIG. In this case, for example, reflected light passing through a region between two lines indicated by reference numeral L2 is captured.

  The photodiode 10 corresponds to an example of a “light receiving unit” and functions to receive reflected light guided by a guiding unit described later. Further, in the present embodiment, the photodiode 20 is further configured to be movable, and such a characteristic configuration will be described in detail later.

  A lens 60 is provided on the optical axis of the laser light L1 emitted from the laser diode 10. The lens 60 is configured as a collimating lens and has a function of converting the laser light L1 from the laser diode 10 into substantially parallel light.

  On the optical path of the laser beam L1 that has passed through the lens 60, the oscillating mirror 31 is disposed. The oscillating mirror 31 is configured to reflect the laser beam L1 from the laser diode 10 toward the rotary deflecting device 40, and is configured to be oscillated. The oscillating mirror 31 changes the direction of reflection from the deflecting unit 41 by relatively changing the incident direction of the laser beam with respect to the deflecting unit 41, and the laser beam L <b> 1 irradiated to the space and the horizontal plane (vertical direction) It functions so as to change the angle formed by a virtual plane orthogonal to the horizontal plane.

  In addition, a mirror driving unit that drives the oscillating mirror 31 with multiple degrees of freedom is provided. Since the technique for driving the mirror with multiple degrees of freedom is well known in the field of galvano mirrors and the like, details thereof will be omitted, but for the mirror driving unit, for example, the oscillating mirror 31 is supported by a gimbal, a pivot bearing or the like. Thereby, it can be set as the structure made to rotationally move to two directions.

  In the example of FIG. 1, the emission direction of the laser light L1 from the laser diode 10 is the X-axis direction, the direction of the central axis 42a of the rotation changing mechanism 40 is the Y-axis direction, and is orthogonal to the X-axis direction and the Y-axis direction. The direction is described as the Z-axis direction. In such a definition, when the angle between the reflecting surface 31a and the XY plane is α, the angle between the reflecting surface 31a and the YZ plane is β, and the angle between the reflecting surface 31a and the XZ plane is γ, the actuator 36 Are configured so that these α, β, and γ can be changed, and the control unit 70 that will be described later controls the actuator 36 to adjust the values of α, β, and γ. The direction of the laser beam L1 and the incident direction when the laser beam L1 is incident on the deflecting unit 41 are determined, whereby the angle formed between the laser beam L1 irradiated into the space and the horizontal plane (virtual plane orthogonal to the vertical direction) Is to be decided.

  In the present embodiment, the control unit 70, the oscillating mirror 31, and the actuator 36 correspond to an example of “irradiation direction changing means”, and the horizontal direction of the laser light L1 irradiated to the external space via the deflection unit 41. At least in the first direction in which the laser beam L1 is inclined with respect to the horizontal direction (for example, the direction of the broken line L1 ′ in FIG. 1) and the laser beam L1 and the horizontal direction than in the first direction. It functions so as to change to the second direction (for example, the direction of the solid line L1 ″ in FIG. 1) with a small angle.

  On the optical axis of the laser beam L1 reflected by the oscillating mirror 31, a rotary deflection device 40 is provided. The rotation deflection device 40 corresponds to an example of a “rotation deflection unit”, and includes a deflection unit 41 configured to be rotatable about a central axis 42a, and a motor that rotationally drives the deflection unit 41. The laser beam L1 generated by the laser diode 10 is deflected toward the external space by the deflection unit 41 while rotating the deflection unit 41.

  The rotation deflection means 40 is mainly composed of a deflection section 41, a support base 43, a shaft section 42, a motor 50, and a rotation angle sensor 52. The deflecting unit 41 is configured as a mirror having a flat reflecting surface 41a, and is arranged so that the reflecting surface 41a faces obliquely upward and the reflecting surface 41a is inclined with respect to the incident laser beam L1. . The support base 43 is configured as a pedestal that supports the deflection unit 41, and is integrally attached to the shaft part 42 rotated by the motor 50. The shaft portion 42 is configured to rotate by receiving the driving force of the motor 50 while being rotatably supported by a bearing (not shown).

  In the laser radar device 1 according to the present embodiment, the deflection region (the region of the reflection surface 41a in the deflection unit 41) that deflects the reflected light in the deflection unit 41 is the deflection region (the region of the reflection surface 41a in the deflection unit 41) that deflects the laser light. It is configured to be sufficiently larger than the area of the reflecting surface 31a in the oscillating mirror 31).

  The motor 50 corresponds to an example of “driving means”, and is constituted by, for example, a known DC motor or a known AC motor. When a drive instruction is issued from the control unit 70, a drive state (for example, rotation timing and rotation speed) is controlled by a motor driver (not shown), and at this time, a predetermined constant is set. It is designed to rotate at a constant rotation speed.

  In this motor, the rotation drive shaft is configured integrally with the shaft portion 42, and the shaft portion 42 and the deflecting portion 41 are configured to normally rotate about the center shaft 42a. The deflection unit 41 is arranged such that an angle θ formed by the deflection surface (reflection surface 41a) and the central axis 42a is a constant angle (for example, 45 °), and this angle when receiving the driving force of the motor 50. It rotates while maintaining θ at a constant angle.

  In the present embodiment, as shown in FIG. 1, a rotation angle sensor 52 that detects the rotation angle position of the shaft portion 42 of the motor 50 (that is, the rotation angle position of the deflection portion 41) is provided. Various types of rotation angle sensors 52 can be used as long as they can detect the rotation angle position of the shaft portion 42, such as a rotary encoder.

  A condensing lens 62 that condenses the reflected light toward the photodiode 20 is provided on the optical path of the reflected light from the rotary deflecting device 40 to the photodiode 20, and the condensing lens 62 and the photodiode are provided. 20 is provided with a filter 64. The condensing lens 62 functions to collect the reflected light from the deflecting unit 41 and guide it to the photodiode 20. The filter 64 functions to transmit the reflected light and remove light other than the reflected light on the optical path of the reflected light from the rotary deflecting device 40 to the photodiode 20. For example, it can be configured by a wavelength selection filter that transmits only light having a specific wavelength corresponding to the reflected light L2 (for example, light having a wavelength in a certain region) and blocks other light.

  In the present embodiment, the rotary deflection device 40 and the condenser lens 62 correspond to an example of “guidance means”, and the laser beam L1 deflected toward the external space by the deflection unit 41 exists in the external space. It functions to guide the reflected light L2 from the object along the guide path defined in the device when reflected by the object. The condenser lens 62 corresponds to an example of “guidance means” and functions to collect the reflected light L2 in the middle of the guidance path.

  The control unit 70 includes one or a plurality of control circuits such as a microcomputer provided with a CPU. The light projecting operation of the laser diode 10 described above, the rotation operation of the motor 50, and the driving operation of the sensor moving unit 22 described later. Is configured to control. Moreover, it is connected to the photodiode 20 and the rotation angle sensor 52, and is configured to be able to acquire signals from these. In addition, a memory (not shown) such as a ROM, a RAM, and a nonvolatile memory is connected to the control unit 70, and the control unit 70 can read and write information in the memory.

  In the present embodiment, the laser diode 10, the photodiode 20, the laser beam deflecting unit 30, the lens 60, the rotation deflecting device 40, the motor 50, and the like are housed in the case 3, and dust and shock protection are achieved. Around the deflection unit 41 in the case 3, a light guide unit 4 that allows the laser light L <b> 1 and the reflected light L <b> 2 to pass is formed so as to surround the deflection unit 41. The light guide 4 is formed in an annular shape centering on the optical axis of the laser beam L1 incident on the deflecting unit 41 and is substantially 360 °, and the glass plate is closed in the form of closing the light guide 4. A laser light transmission plate 5 made of a material such as the like is arranged to prevent dust.

  Furthermore, the laser radar device 1 of the present embodiment is provided with a sensor moving unit 22 that can change the position of the photodiode 20. The sensor moving unit 22 is configured by, for example, a linear actuator, and is configured to operate according to a signal output from the control unit 70, and the photodiode 20 to be moved is moved closer to the condenser lens 62. It is configured to reciprocate between a position (first position) and a position (second position) farther from the condensing lens 62 than at the first position. Specifically, the photodiode 20 is configured to move in the direction of the light receiving optical axis (the optical axis Lr of the condensing lens 62), and even when it is close to the condensing lens 62 (first position), Even at a position far away from the condenser lens 62 (second position), the center of the light receiving surface of the photodiode 20 is displaced so as to be positioned on the optical axis Lr. Various known types of linear actuators can be used, and well-known linear motors, linear vibration actuators, linear electromagnetic solenoids, and the like can be suitably used.

(Object detection operation)
Next, the basic operation of the object detection process (monitoring process) performed by the laser radar device 1 will be described.
In the laser radar apparatus 1 shown in FIG. 1, the deflection unit 41 is rotated at a constant speed by the driving force from the motor 50, and a pulse current is supplied to the laser diode 10 during such rotation. Then, a pulse laser beam (laser beam L1) at a time interval corresponding to the timing and pulse width of the pulse current is output from the laser diode 10. The laser light L1 is projected as diffused light having a certain spread angle, and is converted into parallel light by passing through the lens 60. The laser beam L1 that has passed through the lens 60 is reflected by the oscillating mirror 31, and then is further reflected by the deflecting unit 41 and irradiated toward the space.

  When the laser light L1 emitted from the deflecting unit 41 hits an object (detected object) existing in the external space, a part of the reflected light (reflected) reflected by the detected object and returned to the apparatus side. The light L2) enters the case through the laser light transmission plate 5 and enters the deflecting unit 41. The deflecting unit 41 guides (reflects) the reflected light L2 toward the photodiode 20, and the guided reflected light L2 is collected by the condenser lens 62, passes through the filter 64, and enters the photodiode 20. To do. When the photodiode 20 receives such reflected light L2, the photodiode 20 outputs an electrical signal corresponding to the intensity of the received reflected light L2 (for example, a voltage value corresponding to the received reflected light L2).

  Based on the transmission timing of the pulse signal to the laser diode 10 and the timing at which the light reception signal from the photodiode 20 is output, the controller 70 projects the time T from the light emission of the laser light L1 to the light reception (that is, the laser diode 10). The time from when the pulse laser beam L1 is output until the photodiode 20 receives the reflected light L2 corresponding to the pulse laser beam), the control unit 70 further measures the time T The distance L from the reference position (for example, position P1) in the apparatus to the detected object is calculated based on the light speed C.

  Further, since the control unit 70 controls the amount of displacement of the actuator 36, the displacement of the oscillating mirror 31 when the pulse laser beam L1 is irradiated (the reflection surface 31a of the oscillating mirror 31 and the XY plane The angle α formed, the angle β formed between the reflecting surface 31a and the YZ plane, and the angle γ formed between the reflecting surface 31a and the XZ plane, and from the rotation angle sensor 52 when the pulse laser beam L1 is irradiated. The output value (that is, the rotational displacement θ from the reference angle of the deflection unit 41 at the timing of irradiation with the pulsed laser light L1) can also be grasped. Thus, the angle α formed between the reflecting surface 31a of the oscillating mirror 31 and the XY plane, the angle β formed between the reflecting surface 31a and the YZ plane, and the angle γ formed between the reflecting surface 31a and the XZ plane are determined, and the deflecting unit 41 When the rotational displacement θ is determined, the direction in which the laser beam L1 travels from the deflecting unit 41 is determined in one direction, and thus the control unit 70 outputs these values (α, β, γ, θ) when the pulsed laser beam L1 is output. And the calculated distance L, the orientation of the detected object can be accurately detected.

(View range control)
Next, control of the visual field range will be described.
FIG. 2 is a flowchart illustrating the flow of visual field range switching processing in the laser radar apparatus of FIG. 3A is an explanatory diagram conceptually illustrating the visual field range when the direction of laser light irradiation is set to the first direction in the laser radar apparatus of FIG. 1, and FIG. These are explanatory drawings for conceptually explaining the visual field range when the direction of laser light irradiation is set in the second direction. FIG. 4 is an explanatory diagram for explaining the variable amount of the distance between the light receiving means and the light collecting unit. FIG. 5 is an explanatory diagram for explaining the relationship between the visual field range switched in the external space and the disturbance light generating element. FIG. 6A is a waveform diagram schematically showing an example of a received light waveform when object detection is performed with the first range without switching the visual field range, and FIG. It is a wave form diagram showing roughly an example of a light reception waveform when it switches to 2 ranges and performs object detection. In FIGS. 3 and 4, the light receiving path bent by the reflection by the deflecting unit 41 is conceptually described by linearly representing.

  As shown in FIG. 2, the laser radar device 1 performs a process of switching the inclination angle of the laser light L1 with respect to the horizontal plane with the start of the detection process (S1). In the process of S1 performed immediately after the start process of FIG. 2, the inclination angle of the laser beam L1 with respect to the horizontal plane is set to, for example, a default angle (such as θ1 shown in FIG. 1).

  After the process of S1, a process of switching to the visual field range corresponding to the tilt angle set in S1 is performed (S2). For example, when the direction of the laser beam is set to the first direction (the direction indicated by the symbol L1 ′ in FIG. 1), the visual field range at the photodiode 20 is set to the first range AR1 as shown in FIG. Set to. Further, when the laser beam direction is set to the second direction (the direction of L1 ″ in FIG. 1) in S1, the field-of-view range at the photodiode 20 is set to the second direction as shown in FIG. In this embodiment, the vertical extent centered on the optical axis C is narrower in the second range AR2 than in the first range AR1, and in the first range AR1, Compared to the second range AR2, the upper side and the lower side are configured to be a light receiving range.

  In the present embodiment, the control unit 70 and the sensor driving unit 22 correspond to an example of a “field-of-view range switching unit”, and the distance (path length) from the condenser lens 62 to the photodiode 20 in the guiding path by moving the photodiode 20. The function of changing the field of view in the external space that can be received by the photodiode 20 is changed.

  After the processing of S1 and S2, detection processing is performed with the tilt angle and field of view range set in these processing (S3). In this example, detection processing of a certain angle range is performed in the tilt angle and field of view range set in S1 and S2, and when the predetermined start timing comes after the switching of S2, or the deflection unit Laser scanning is performed within the detection area until the deflection unit 41 is displaced within a certain angular range (for example, one round (an angular range of 360 °)), for example, when 41 is at a predetermined angle (rotation starting point). When the photodiode 20 receives reflected light from the object in the detection area while this detection process is being performed, the object is The position and height are calculated (S3).

  Such a detection process continues after the process of S2 until the deflection unit 41 rotates by a certain angle, and proceeds to No in S4 when the deflection unit 41 does not rotate by a certain angle range from the rotation starting point. Therefore, the detection process of S3 is repeated. On the other hand, when the deflection unit 41 has performed rotation for a certain angle range from the rotation starting point, the process proceeds to Yes in S4, and returns to S1 and S2 to perform the tilt angle setting process and the visual field range switching process.

  When the process proceeds to Yes in S4 and returns to S1 and S2, the inclination angle of the laser light L1 with respect to the horizontal plane is switched from the angle set in the latest process of S3. In the present embodiment, the above-mentioned “irradiation direction changing means” changes the direction of the laser light L1 in the first direction (direction in which the inclination angle with respect to the horizontal plane is θ1) and the second direction (direction in which the inclination angle with respect to the horizontal plane is 0). When the inclination angle of the laser beam L1 with respect to the horizontal plane is set to θ1 in the most recent processing of S3 before performing S1, the laser beam with respect to the horizontal plane is set in this processing of S1. The inclination angle of L1 is switched from θ1 to 0 °. In this case, in the latest processing of S3, the field of view range (the first range AR1 shown in FIG. 3A) corresponding to the tilt angle θ1 was set, but in the processing of S2 immediately after that, switching was performed. The visual field range (second range AR2 shown in FIG. 3B) corresponding to the tilt angle (0 °) is switched. After switching the visual field range in this way, the object detection process is performed again within a certain angle range (S3, S4).

  As a method for determining whether or not laser scanning has been performed in a certain angle range in S3, for example, determination is made based on whether or not a predetermined number of pulse outputs have been performed from the start starting point after S2. The method can be used. Alternatively, when scanning is started in S1, the rotation position (rotation angle with respect to the reference angle) of the deflection unit 41 at the start is recorded in a memory (not shown), and the deflection unit 41 is fixed based on the recorded contents. It may be determined whether or not the range has been rotated.

  The above-mentioned “irradiation direction changing means” is the first direction during which the deflection unit 41 rotates at least one round after the direction of the laser beam L1 is switched to the first direction (the direction of the inclination angle θ1 with the horizontal plane). In the second direction while the deflecting unit 41 rotates at least one round after the direction of the laser beam L1 is switched to the second direction (the direction at an inclination angle of 0 ° with respect to the horizontal plane). The direction is controlled so that The above-described “field-of-view range changing means” maintains the field-of-view range in the relatively wide first range AR1 and the direction of the laser light L1 is the first in the circulation in which the direction of the laser light L1 is maintained in the first direction. In the circulation maintained in two directions, the switching control of the path length b (FIG. 4) is performed so that the visual field range is maintained in the relatively narrow second range AR2.

  Further, the maximum distance b of the distance (path length) between the light receiving sensor 20 and the condensing lens 62 can be set by, for example, an expression as shown in FIG. In this equation, L is the maximum detection distance from the laser radar device 1, D is the lens effective field diameter, and f is the lens focal length. S is the laser spot diameter at the maximum detection distance, and θ is the vertical scan angle (inclination angle with respect to the horizontal plane). As described above, if the angle θ (inclination angle θ1 in the first direction) in the direction of the boundary position (front and upper boundary position) where the object is to be detected, the maximum detection distance L, the characteristics of the light receiving lens, and the like are determined, 4 (A), the distance b between the light receiving sensor 20 and the condenser lens 62 can be set, and this boundary position can be included in the detection range.

(Main effects of the first embodiment)
As described above, in the present embodiment, “field-of-view range changing means” capable of changing the field-of-view range in the external space that can be received by the photodiode 20 is provided. The visual field range is changed by adjusting the path length from the optical lens 62 to the photodiode 20. And, as indicated by reference numeral L1 ′ in FIG. 1, when the direction of the laser light L1 is set to the first direction (the direction in which the tilt angle with respect to the horizontal plane becomes relatively large) by the “irradiation direction changing unit”, As shown in FIG. 3A, the distance between the condenser lens 62 and the light receiving surface 20a of the photodiode 20 is set to be relatively short, and the visual field range that can be received by the photodiode 20 is set to the first range AR1. Yes. As described above, when the laser beam is irradiated obliquely upward (first direction) having a relatively large inclination with respect to the horizontal direction, the field of view range can be set relatively wide. It is easy to receive regular detection light (reflected light reflected by an object of the irradiated laser light L1 ′). Therefore, it is possible to perform laser scanning obliquely upward (first direction) away from the horizontal direction and object detection in this direction.

  On the other hand, when the direction of the laser beam L1 is set to the second direction (the direction in which the inclination angle with respect to the horizontal plane becomes relatively small) as indicated by the symbol L1 ″ in FIG. In addition, the visual field range is set to the second range AR2 which is narrower than the first range AR1, so that when the laser light L1 is irradiated near the horizontal direction (second direction), the visual field range is relatively narrow. Therefore, when performing object detection by irradiating the laser beam L1 in the direction near the horizontal direction, disturbance light from the upper side or the lower side far away from the irradiation direction of the laser beam L1 is used as much as possible. It is possible to prevent light from being received.

  As described above, since the influence of disturbance light can be reliably suppressed, it is possible to effectively prevent erroneous detection of object detection caused by disturbance light. For example, when an object is to be detected outdoors as shown in FIG. 5, the laser beam is irradiated in the second direction (near the horizontal direction) while the field-of-view range is set to the first range (see symbol AR1 ′ in FIG. 5). Then, when the reflected light from the objects Wa and Wb is received, not only the regular reflected light from the objects Wa and Wb but also sunlight having high energy is received, as shown in FIG. In particular, reflected light with a small amount of light from a long-distance object is drowned out by sunlight. However, in the present embodiment, when laser light is irradiated in the second direction (near the horizontal direction), the upper side where such sunlight is likely to enter is not set as the visual field range as much as possible, but is limited to the vicinity of the horizontal direction necessary for detection. Since the visual field range (second range) can be set, light reception such as sunlight can be suppressed, and erroneous detection due to such disturbance light can be effectively prevented.

Further, in the present embodiment, the “irradiation direction changing unit” is configured so that, after the direction of the laser beam is switched to the first direction (direction in which the inclination angle θ1 is set), the deflection unit 41 is rotated at least one turn. After maintaining in the first direction and switching to the second direction (direction in which the tilt angle is 0 °), the direction control is performed so that the deflection unit 41 is maintained in the second direction for at least one turn. Is going. Then, the “field-of-view range changing unit” maintains the field-of-view range in the first range AR1 in the circulation in which the direction of the laser light is maintained in the first direction, and in the circuit in which the direction of the laser light is maintained in the second direction. The path length (distance between the light receiving surface 20a and the condensing lens 62) is controlled so as to maintain the visual field range in the second range AR2.
In this configuration, after the direction of the laser beam is switched to the first direction, the deflection unit 41 is maintained in that direction for one or more rotations, while the visual field range is maintained in the first range AR1. Similarly, after the direction of the laser beam is switched to the second direction, the deflection unit 41 is maintained in that direction for one or more rotations, while the visual field range is maintained in the second range AR2. Therefore, the field-of-view range switching control (that is, the path length switching control) is not repeated many times during one round of the deflection unit 41, and the electrical and mechanical loads associated with the switching control are reliably reduced. Can do.
Moreover, according to the said structure, it becomes easy to increase the speed of the deflection | deviation part 41. FIG. For example, when the method of switching the visual field range a plurality of times during one round of the deflection unit is used, it is necessary to switch the visual field range by a fraction or tens of the period of the deflection unit 41, which is inexpensive. Such a high-speed drive is difficult with the drive means. In addition, although it is conceivable to switch the visual field range to a certain degree of speed, such a drive means is expensive, and even if such a drive means is used, the visual field range is switched multiple times during one round. According to the method, since the rotation period of the deflecting unit needs to be several times or several tens of times the switching range of the visual field range, it is difficult to increase the speed of the deflecting unit 41. On the other hand, in the above configuration, since the field-of-view range switching interval can be set longer than the rotation period of the deflecting unit 41, the field-of-view range can be switched at high speed, and the switching interval is not so short. Even in this case, it becomes easy to cope with the speeding up of the deflection unit.

[Second Embodiment]
Next, a second embodiment will be described.
FIG. 7 is a schematic cross-sectional view of a laser radar device according to the second embodiment of the present invention. FIG. 8 is a schematic cross-sectional view schematically showing a configuration in which the laser radar device of FIG. 7 is cut in a direction orthogonal to the central axis. FIG. 9 is an explanatory diagram showing a state after the visual field range is switched from the state of FIG.

  The second embodiment is different from the first embodiment in that a concave mirror 41 is used as a light collecting unit. In the present embodiment, the rotary deflection device 40 is configured as “guidance means”, and the “deflection unit” is configured by a concave mirror. The concave mirror 41 is configured to deflect the laser light from the laser diode 10 to the external space side and to guide the reflected light from the detection object to the light receiving means side while collecting the reflected light. Also in this embodiment, as in the first embodiment, the “field-of-view range changing means” is configured by the control circuit 70 and the sensor moving unit 22, and the light receiving sensor 20 is moved to move from the concave mirror 41 to the light receiving sensor 20. The visual field range in the external space is changed by changing the path length. Even in this configuration, the field-of-view range can be switched in the same manner as in the first embodiment, and when laser light is irradiated in the first direction (see symbol L1 ′ shown in FIG. 7), it is the same as in FIG. When the laser beam is irradiated in the second direction (see symbol L1 ″ shown in FIG. 9), the visual field range can be set as in FIG. 3B. 7 can be set to a relatively narrow second range AR2.In Fig. 7, the state of the reflected light L2 when the laser beam is irradiated in the first direction (see the symbol L1 'shown in Fig. 7) is denoted by the symbol L2'. In FIG. 9, the state of the reflected light L2 when the laser beam is irradiated in the second direction (see the symbol L1 ″ shown in FIG. 9) is conceptually indicated by the symbol L2 ″. ing.

  Further, in the present embodiment, a “setting unit” for setting a detection area is provided. The “setting unit” sets a predetermined rotation angle range as a “detection range” in the entire rotation angle range of the deflection unit 41, and The detection area is set so that the non-detection range is outside the predetermined rotation angle range. For example, the laser is moved forward from the rotation position of the deflection unit 41 when the laser beam is irradiated to the line F1 shown in FIG. 8 to the rotation position of the deflection unit 41 when the laser beam is irradiated to the line F2. The rotation angle range when the light is irradiated is set as a detection range, and the other angle range (angle range in which the laser beams are irradiated to the walls 5e, 5d, and 5f) is set as the “non-detection range”.

  In this embodiment, for example, an actuator that integrally swings the laser diode 10 and the lens 60 is used, and the actuator is driven and controlled by the control circuit 70 to change the irradiation direction of the laser light, thereby changing the laser from the concave mirror 41. The light irradiation direction can be changed. In this case, the control circuit 70 corresponding to the “irradiation direction changing means” and the actuator (not shown) change the rotation angle of the concave mirror 41 after the direction of the laser light L1 is switched to the first direction (see FIG. 7). The “field-of-view range changing means” changes the path length from the concave mirror 41 to the photodiode 20 at the timing when the rotational position of the concave mirror 41 is in the non-detection range. Configured to do. Similarly, after the direction of the laser beam L1 is switched to the second direction (see FIG. 9), the rotation angle of the concave mirror 41 is maintained in the second direction throughout the period within the detection range. The “field-of-view range changing means” is configured to change the path length from the concave mirror 41 to the photodiode 20 at the timing when the rotational position of the concave mirror 41 is in the non-detection range.

(Main effects of the second embodiment)
The laser radar device 200 according to the second embodiment can achieve the same effects as those of the first embodiment.
In the present embodiment, the concave mirror 41 having a condensing function is used, and the photodiode 20 is moved to change the path length from the concave mirror 41 to the photodiode 20. In this configuration, it is not necessary to provide a dedicated condensing means on the path from the concave mirror 41 to the photodiode 20, or even if provided, the size and number can be reduced, the number of parts can be reduced, and the device configuration Can be simplified.

  In the present embodiment, the visual field range can be efficiently switched using a period in which the rotation angle of the concave mirror 41 is in the non-detection range, and at the time of detection (when the rotation angle of the deflection unit is in the detection range). The laser beam direction can be stably maintained in the first direction or the second direction. In addition, since the visual field range is switched once in one or more laps, the electrical and mechanical loads associated with the switching control are reduced compared to the method of switching the visual field range multiple times during one lap. This makes it easy to increase the speed of the concave mirror 41.

[Other Embodiments]
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  In the first embodiment, laser beam scanning and object detection are performed in an angle range of 360 ° (that is, a range in which the deflecting unit makes one rotation) with the laser beam set in the first direction and the visual field range set to the first range. For example, while the laser beam is set in the first direction and the visual field range is set in the first range, the laser beam scanning and the object detection may be performed while the deflection unit rotates a plurality of times. Good. Similarly, scanning of the laser beam and object detection may be performed while the deflection unit rotates a plurality of times with the laser beam set in the second direction and the visual field range set in the second range.

  In the above-described embodiment, the configuration in which the irradiation angle of the laser beam with respect to the horizontal plane can be switched in two stages is exemplified. However, the tilt angle of the laser beam with respect to the horizontal plane may be switched in three or more stages. In this case, for example, a linear actuator whose position can be linearly adjusted is used so that the distance between the light receiving surface 20a of the photodiode 20 and the condenser lens 62 can be set in multiple stages, and the inclination angle of the laser light is large. It is preferable that the visual field range can be set in multiple stages so that the visual field range becomes wider.

  In the above embodiment, the laser radar device capable of three-dimensionally scanning the laser light has been exemplified. However, the method of three-dimensional scanning is not limited to the above example. For example, the method of displacing the deflection unit or the entire case Various publicly known methods such as a method of displacing can be used.

DESCRIPTION OF SYMBOLS 1 ... Laser radar apparatus 10 ... Laser diode (laser beam generation means)
20 ... Photodiode (light receiving means)
22 ... Sensor moving part (field-of-view range changing means)
31 ... Oscillating mirror (irradiation direction changing means)
36 ... Actuator (irradiation direction changing means)
40 ... Rotational deflection device (rotational deflection means, guidance means)
DESCRIPTION OF SYMBOLS 41 ... Deflection part 42a ... Center axis 50 ... Motor (drive means)
62 ... Condensing lens (condensing part, guiding means)
70: Control unit (irradiation direction changing means, visual field range changing means, setting means)
240 ... Rotational deflection device (guidance means)
241 ... Concave mirror (deflection part)

Claims (4)

Laser light generating means for generating laser light;
A deflection unit configured to be rotatable about a predetermined central axis; and a driving unit that rotationally drives the deflection unit, and the laser beam generated by the laser beam generation unit while rotating the deflection unit. Rotation deflecting means for deflecting toward the external space by the deflecting unit;
The direction of the laser beam irradiated to the external space through the deflection unit with respect to the horizontal direction is at least as compared with the first direction in which the laser beam is inclined with respect to the horizontal direction and the first direction. And an irradiation direction changing means for changing to a second direction having a small angle between the laser beam and the horizontal direction,
A configuration in which when the laser beam deflected toward the external space by the deflecting unit is reflected by an object existing in the external space, the reflected light from the object is guided along a guide path defined in the apparatus. And guiding means having a condensing part for condensing the reflected light in the middle of the guiding path;
A light receiving means for receiving the reflected light guided by the guiding means;
The external space that can receive light by the light receiving unit by moving at least one of the light collecting unit and the light receiving unit to change a path length from the light collecting unit to the light receiving unit in the guide path. Visual field range changing means for changing the visual field range at
With
The field-of-view range changing means sets the field-of-view range to the first range when the direction of the laser light is set to the first direction by the irradiation direction changing means, and the direction of the laser light is When set in the second direction, the visual field range is set to the second range, and the visual field range is narrower than the first range, so that the visual field range is narrower than the first range. A laser radar device characterized by adjusting the length of the path to the light receiving means. The rotational deflection means is configured as at least a part of the guiding means,
The deflecting unit is configured by a concave mirror that deflects the laser light from the laser light generating means to the external space side and guides the reflected light from the detection object to the light receiving means side while condensing the reflected light. And
2. The field-of-view range changing unit changes the field-of-view range in the external space by moving the light-receiving unit to change the path length from the concave mirror to the light-receiving unit. The laser radar device described in 1. After the direction of the laser beam is switched to the first direction, the irradiation direction changing unit maintains the first direction for at least one turn and switches to the second direction. Later, while the deflection unit rotates at least one round or more, the direction is controlled so as to be maintained in the second direction,
The field-of-view range changing unit maintains the field-of-view range in the first range and the direction of the laser light is maintained in the second direction in a round in which the direction of the laser light is maintained in the first direction. 3. The laser radar device according to claim 1, wherein the path length switching control is performed so as to maintain the field-of-view range in the second range in a round. A setting means for setting a detection area so that a predetermined rotation angle range is set as a detection range and an outside of the predetermined rotation angle range is set as a non-detection range in the entire rotation angle range of the deflection unit;
The irradiation direction changing means maintains the rotation direction of the deflection unit in the first direction throughout the period in which the rotation angle of the deflection unit is within the detection range after switching the direction of the laser light to the first direction, and in the second direction. After switching, the rotation angle of the deflecting unit is maintained in the second direction throughout a period in which the detection unit is within the detection range,
2. The visual field range changing unit performs an operation of changing the path length from the light collecting unit to the light receiving unit at a timing when the rotation position of the deflecting unit is in the non-detection range. Alternatively, the laser radar device according to claim 2.

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