JP2009128014A - Beam irradiation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a beam irradiation apparatus capable of performing scanning operation in a target area, with high accuracy. <P>SOLUTION: A control processing unit 202 two-dimensionally drives a mirror actuator 100, in a region near a first reference position and a second reference position, and stores output values (coordinate data) of PSD 106, upon the detection of these reference positions. When the state of PSD changes from an initial state due to influences, such as, temperature change and changes due to aging, stored coordinate data (a first reference point R1' and a second reference point R2') deviates from the coordinate data (a first reference point R1 and a second reference point R2) set at the initial state, as shown in Fig. 8(b). The control processing unit 202 calibrates the data of a target value table 202a, based on deviations ΔP1 and ΔP2 of these two reference points, and deviations ΔQ1 and ΔQ2, and performs servo operation using the calibrated target value table. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a beam irradiation apparatus that irradiates a target area with laser light, and in particular, based on reflected light when the target area is irradiated with laser light, the presence or absence of an obstacle in the target area and the distance to the obstacle. It is suitable for use in a beam irradiation device mounted on a so-called laser laser.

  In recent years, in order to improve safety during traveling, a laser radar that irradiates laser light forward in the traveling direction and detects the presence or absence of an obstacle in the target area and the distance to the obstacle from the state of the reflected light, It is installed in home passenger cars. In general, a laser radar scans a laser beam within a target area, detects the presence or absence of an obstacle at each scan position from the presence or absence of reflected light at each scan position, and further determines from the irradiation timing of the laser light at each scan position. Based on the time required to receive the reflected light, the distance to the obstacle at the scan position is detected.

  Conventionally, as a laser beam scanning mechanism, a scanning mechanism using a polygon mirror and a lens driving type scanning mechanism for driving a scanning lens two-dimensionally (for example, see Patent Document 1 below) are known.

  As a new scanning mechanism different from these scanning mechanisms, the applicant has previously filed Japanese Patent Application No. 2006-121762 and has proposed a mirror rotation type scanning mechanism. In this scan mechanism, the mirror is supported so that it can be driven in two axes, and the mirror is rotated about each drive shaft by an electromagnetic drive force between the coil and the magnet. The laser light is incident on the mirror from an oblique direction, and the reflected light is irradiated toward the target area. The mirror is driven two-dimensionally around each drive axis, whereby the laser beam is scanned in a two-dimensional direction within the target area.

  In order to increase the detection accuracy of the laser radar, it is necessary to appropriately scan the laser beam within the target area. For this reason, in the beam irradiation apparatus, a servo operation is required to align the scan position of the laser beam along the intended trajectory. In the mirror rotation type scanning mechanism, the scan position of the laser beam in the target area corresponds one-to-one with the rotation position of the mirror. Therefore, the scan position of the laser beam can be detected by detecting the rotational position of the mirror. Here, the rotation position of the mirror can be detected, for example, by detecting the rotation position of another member that rotates with the mirror.

  FIG. 14 is a diagram illustrating a configuration example for detecting the rotational position of the mirror. FIG. 5A shows a configuration example when a parallel plate-shaped transparent body is used as another member, and FIG. 4B shows a configuration example when a mirror is used as another member.

  In FIG. 6A, reference numeral 601 denotes a semiconductor laser, 602 denotes a transparent body, and 603 denotes a photodetector (PSD: Position Sensing Device). Laser light (servo light) emitted from the semiconductor laser 601 is refracted by a transparent body 602 arranged to be inclined with respect to the laser optical axis, and is received by the photodetector 603. Here, when the transparent body 602 rotates as shown by an arrow, the optical path of the servo light changes as indicated by a dotted line in the figure, and the light receiving position of the servo light on the photodetector 603 changes. Therefore, the rotational position of the transparent body 602 can be detected from the light receiving position of the servo light detected by the photodetector 603.

  In FIG. 6B, 611 is a semiconductor laser, 612 is a mirror, and 613 is a photodetector (PSD). Laser light (servo light) emitted from the semiconductor laser 611 is reflected by a mirror 612 arranged to be inclined with respect to the laser optical axis, and received by the photodetector 613. Here, when the mirror 612 rotates as shown by an arrow, the optical path of the servo light changes as indicated by a dotted line in the figure, and the light receiving position of the servo light on the photodetector 613 changes. Therefore, the rotational position of the mirror 612 can be detected from the light receiving position of the servo light detected by the photodetector 613.

In addition, the detection of the scanning position of the laser beam in the target region may be performed by branching a part of the laser beam toward the target region by a beam splitter or the like and receiving the branched light (servo light) by a photodetector. It can also be done.
Japanese Patent Laid-Open No. 11-83988

  By the way, the output value from the photodetector (PSD) is affected by temperature change and secular change. That is, even if the servo light is irradiated to the same position on the PSD light receiving surface, the output value may vary due to the difference in the temperature of the photodetector. Moreover, there is a possibility that the output value will shift as the usage period of the device becomes longer. Thus, if the output values of the photodetector at the same irradiation position vary, there is a possibility that an accurate servo operation cannot be performed using these output values.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a beam irradiation apparatus capable of accurately performing a scanning operation in a target region using a laser beam.

  A beam irradiation apparatus according to a first aspect of the invention includes an actuator that scans a scanning laser beam in a two-dimensional direction, a drive control unit that drives and controls the actuator, and a servo light traveling direction that changes in accordance with the driving of the actuator. A servo light displacement unit to be received, a light receiving position detector that receives the servo light and outputs a signal corresponding to the light receiving position, and a light receiving position detector when the scanning laser light appropriately scans the target area A trajectory information storage unit that stores trajectory information related to the ideal trajectory of the servo light in the reference, and a reference relating to a reference light receiving position of the servo light on the light receiving position detector when the actuator is positioned at a preset specific position A reference position storage unit for storing information; a specific position detection unit for detecting that the actuator is at the specific position; Based on an output signal from the light receiving position detector when the specific position detecting unit detects that the actuator is at the specific position and the reference information stored in the reference position storage unit, A trajectory information calibrating unit that calibrates the scanning laser beam based on the output signal from the light receiving position detector and the trajectory information calibrated by the trajectory information calibrating unit. Controls the actuator to scan in the target area.

  According to a second aspect of the present invention, in the beam irradiation apparatus according to the first aspect, the specific position detector detects the first specific position and the second specific position, and the first specific position and the second specific position are detected. The specific position is set so that the light receiving position of the servo laser light on the light receiving position detector when the actuator is at the specific position is substantially diagonal on the light receiving surface of the light receiving position detector. It is characterized by.

  According to a third aspect of the present invention, in the beam irradiation apparatus according to the second aspect, the specific position detection unit includes a position detection light source that emits position detection light, and the progress of the position detection light as the actuator is driven. A detection light displacing portion that changes a direction, a first light receiver that receives the position detection light when the actuator is at the first specific position, and a case where the actuator is at the second specific position. And a second light receiver for receiving the position detection light.

  Here, the specific position detection unit detects, for example, a position where the received light amount of the position detection light in the first and second light receivers is maximum as the specific position.

  According to a fourth aspect of the present invention, in the beam irradiation apparatus according to the third aspect, the light source that emits the scanning laser light is also used as the position detection light source, and light is provided before the first light receiver and the second light receiver. A filter for attenuating the strength is provided.

  According to a fifth aspect of the present invention, in the beam irradiation device according to any one of the first to fourth aspects, a temperature detection unit that detects a temperature of the light receiving position detector is provided, and the drive control unit is configured to detect the temperature. When the temperature detected by the unit reaches a preset temperature, the actuator is driven in the vicinity range of the specific position, and the trajectory information calibration unit is configured to drive the trajectory according to the driving of the actuator in the vicinity range. It is characterized by proofreading information.

  According to a sixth aspect of the present invention, in the beam irradiation apparatus according to any one of the first to fifth aspects, the drive control unit refers to speed information of a moving body on which the beam irradiation apparatus is mounted, and the moving body When the movable body is in a moving state, the actuator is controlled so that the scanning laser beam scans within the target area, and when the moving body is in a stopped state, the actuator is driven in the vicinity of the specific position, The trajectory information calibration unit calibrates the trajectory information in accordance with driving of the actuator in the vicinity range.

  According to the first aspect of the present invention, the trajectory information in the trajectory information storage unit is based on the output signal from the light receiving position detector when the actuator is at the specific position and the reference information stored in the reference position storage unit. Is calibrated to meet Here, the reference information is based on, for example, a signal output from the light receiving position detector when the actuator is positioned at a specific position under the condition equivalent to setting an ideal trajectory for servo light. . Therefore, this reference information is compared with the signal actually output from the light receiving position detector when the actuator is positioned at a specific position during actual operation, and the trajectory information in the trajectory information storage unit is adapted during actual operation. If the calibration is performed, the scanning laser light can be appropriately scanned in the target area by controlling the actuator using the orbit information after the calibration. Therefore, even if the output signal from the light receiving position detector changes from that at the time of setting the ideal orbit due to temperature change or aging, etc., highly accurate servo operation can be realized, and within the target area by scanning laser light Can be accurately performed.

  According to the second aspect of the present invention, since the change in the output signal can be detected at two light receiving positions that are substantially diagonal on the light receiving surface of the light receiving position detector, the number of points to be detected is reduced as much as possible. Thus, it is possible to calibrate the trajectory information in consideration of the variation in the output value due to the difference in the location on the light receiving surface while suppressing an increase in the number of components such as sensors.

  Furthermore, according to the invention of claim 3, position detection can be performed in a non-contact state with the actuator, and an extra load can be prevented from being applied to the actuator.

  Furthermore, according to the invention of claim 4, since the scanning light source can be used as the position detection light source, the configuration can be simplified.

  Further, according to the invention of claim 5, since the orbit information is calibrated when the temperature is such that the output signal from the light receiving position detector is affected, the deterioration of the servo operation accuracy due to the temperature change is prevented. it can. In addition, since the trajectory information is not calibrated unless the temperature is such that the output signal is affected, the scan operation within the target region is not frequently interrupted for the calibration of the trajectory information.

  Furthermore, the scanning operation in the target area is performed to detect an obstacle in the target area, and this obstacle is detected when the moving body on which the beam irradiation device is mounted is in a moving state. Especially needed. According to the invention of claim 6, since orbit information is calibrated when the moving body is stopped, the obstacle detection operation is not interrupted when the moving body is moving. Is secured.

  The effects and significance of the present invention will become more apparent from the following description of embodiments. However, the following embodiment is merely an example when the present invention is implemented, and the present invention is not limited to the following embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, the present invention is applied to a laser radar. In the present embodiment, laser light is incident on the mirror from the horizontal direction. By rotating the mirror in the horizontal direction and the vertical direction, the laser beam is scanned in a two-dimensional direction in the target area.

  FIG. 1 shows a configuration of a mirror actuator according to the present embodiment. FIG. 4A is an exploded perspective view of the actuator, and FIG. 4B is a perspective view of the actuator in an assembled state.

  In FIG. 1A, reference numeral 10 denotes a mirror holder. The mirror holder 10 is formed with support shafts 11 and 12 having stoppers at the ends. A flat mirror 13 is mounted on the front surface of the mirror holder 10, and a coil 14 is mounted on the back surface. The coil 14 is wound in a square shape. A plate-like mirror 15 is mounted on the support shaft 12 of the mirror holder 10 so that the reflecting surface is parallel to the reflecting surface of the mirror 13. The mirror 15 has a reflective surface 15a on the same side as the reflective surface of the mirror 13, and has a reflective surface 15b on the surface opposite to the reflective surface 15a.

  Reference numeral 20 denotes a movable frame that supports the mirror holder 10 so as to be rotatable about the support shafts 11 and 12. An opening 21 for accommodating the mirror holder 10 is formed in the movable frame 20, and grooves 22 and 23 that engage with the support shafts 11 and 12 of the mirror holder 10 are formed. Further, support shafts 24 and 25 having stoppers at the ends are formed on the side surface of the movable frame 20, and a coil 26 is mounted on the back surface. The coil 26 is wound in a square shape.

  Reference numeral 30 denotes a fixed frame that rotatably supports the movable frame 20 around the support shafts 24 and 25. The fixed frame 30 has a recess 31 for accommodating the movable frame 20, and grooves 32 and 33 that engage with the support shafts 24 and 25 of the movable frame 20. Further, a magnet 34 for applying a magnetic field to the coil 14 and a magnet 35 for applying a magnetic field to the coil 26 are mounted on the inner surface of the fixed frame 30. Each of the grooves 32 and 33 extends from the front surface of the fixed frame 30 to the gap between the upper and lower two magnets 35.

  Reference numeral 40 denotes a pressing plate that presses the support shafts 24 and 25 from the front so that the support shafts 24 and 25 of the movable frame 20 do not fall out of the grooves 32 and 33. Note that a holding plate that restricts the support shafts 11 and 12 of the mirror holder 10 from dropping from the grooves 22 and 23 of the movable frame 20 is not shown.

  When assembling the actuator, the support shafts 11 and 12 of the mirror holder 10 are engaged with the grooves 22 and 23 of the movable frame 20, and the front surfaces of the support shafts 11 and 12 are further pressed so as to hold the pressing plate (see FIG. (Not shown) is mounted on the front surface of the movable frame 20. Thereby, the mirror holder 10 is rotatably supported by the movable frame 20.

  After mounting the mirror holder 10 to the movable frame 20 in this way, the support shafts 24 and 25 of the movable frame 20 are engaged with the grooves 32 and 33 of the fixed frame 30 and the front surfaces of the support shafts 32 and 33 are further pressed. In this manner, the holding plate 40 is attached to the front surface of the magnet 35. Thereby, the movable frame 20 is rotatably attached to the fixed frame 30, and the assembly of the actuator is completed.

  When the mirror holder 10 is rotated about the support shafts 11 and 12 with respect to the movable frame 20, the mirrors 13 and 15 are rotated accordingly. Further, when the movable frame 20 rotates about the support shafts 24 and 25 with respect to the fixed frame 30, the mirror holder 10 rotates accordingly, and the mirrors 13 and 15 rotate integrally with the mirror holder 10. . As described above, the mirror holder 10 is supported by the support shafts 11 and 12 and the support shafts 24 and 25 orthogonal to each other so as to be rotatable in a two-dimensional direction. As the mirror holder 10 rotates, the mirrors 13 and 15 are supported. Rotates in a two-dimensional direction.

  In the assembled state shown in FIG. 5B, the two magnets 34 are arranged and polarized so that when a current is applied to the coil 14, a rotational force about the support shafts 11 and 12 is generated in the mirror holder 10. Has been adjusted. Therefore, when a current is applied to the coil 14, the mirror holder 10 rotates about the support shafts 11 and 12 by the electromagnetic driving force generated in the coil 14.

  Further, in the assembled state shown in FIG. 5B, the two magnets 35 are arranged and polarized so that when the current is applied to the coil 26, the movable frame 20 generates rotational power about the support shafts 24 and 25. Has been adjusted. Therefore, when a current is applied to the coil 26, the movable frame 20 rotates about the support shafts 24 and 25 by the electromagnetic driving force generated in the coil 26.

  Thus, by applying an electric current to the coil 14 and the coil 26, the mirror holder 10 and the movable frame 20 rotate around the support shafts 11 and 12 and the support shafts 24 and 25, respectively. Thereby, the mirrors 13 and 15 are united with the mirror holder 10 and rotated in a two-dimensional direction.

  FIG. 2 shows the configuration of the laser radar according to the present embodiment. In the figure, a configuration (described later) for data calibration of the target value table 202a is omitted.

  As illustrated, the laser radar includes a beam irradiation head 201, a control processing unit 202, an actuator driving unit 203, and a laser driving unit 204.

  The beam irradiation head 201 scans the laser beam in the scanning region set in the front space. As shown in the figure, in addition to the mirror actuator 100, the beam irradiation head 201 includes a semiconductor laser 101, a collimating lens 102, an aberration plate 103, a semiconductor laser 104, a condensing lens 105, a PSD 106, and a light receiving lens 107. PD (Photo Detector) 108 is provided.

  The semiconductor laser 101 for scanning emits laser light (hereinafter referred to as “scanning laser light”) in the X-axis direction of FIG. The emitted scanning laser light is converted into parallel light by the collimator lens 102, further optically adjusted by the aberration plate 103, and then incident on the flat mirror 13 supported by the mirror actuator 100.

  The scanning laser light incident on the mirror 13 is reflected by the mirror 13 and travels toward the target area. When the mirror 13 is driven two-dimensionally by the mirror actuator 100, the scanning laser light is scanned in the two-dimensional direction (the XY plane direction in FIG. 2) within the target region. The aberration plate 103 is for adjusting the shape of the scanning laser beam in the target area. Instead of the aberration plate 103, a combination of two cylindrical lenses may be provided.

  The servo semiconductor laser 104 emits laser light (hereinafter referred to as “servo laser light”) in the X-axis direction in FIG. 2 and in the direction opposite to the scanning laser light. The emitted servo laser light is reflected by the reflecting surface 15 b of the mirror 15 and then condensed on the light receiving surface of the PSD 106 by the condenser lens 105. The condensing lens 107 condenses the reflected light from the target area on the PD 108. The PD 108 outputs a signal corresponding to the received light intensity to the control processing unit 202.

  FIG. 3A is a diagram (side sectional view) showing the configuration of the PSD 106, and FIG. 3B is a diagram showing the light receiving surface of the PSD 106.

  As shown in FIG. 3A, the PSD 106 has a structure in which a P-type resistance layer serving as a light-receiving surface and a resistance layer is formed on the surface of an N-type high-resistance silicon substrate. On the surface of the resistance layer, electrodes X1 and X2 for outputting a photocurrent in the horizontal direction of FIG. 2B and electrodes Y1 and Y2 for outputting a photocurrent in the vertical direction (shown in FIG. 1A). (Omitted) is formed. A common electrode is formed on the back side.

  When the servo laser beam is irradiated onto the light receiving surface, an electric charge proportional to the amount of light is generated at the irradiation position. This electric charge reaches the resistance layer as a photocurrent, is divided in inverse proportion to the distance to each electrode, and is output from the electrodes X1, X2, Y1, and Y2. Here, the current output from the electrodes X1, X2, Y1, and Y2 has a magnitude divided in inverse proportion to the distance from the irradiation position of the servo laser beam to each electrode. Therefore, based on the current values output from the electrodes X1, X2, Y1, and Y2, the light irradiation position on the light receiving surface can be detected two-dimensionally.

  The irradiation position of the servo laser light on the PSD 106 is displaced according to the tilt state of the mirror 15. On the other hand, since the mirror 15 rotates integrally with the mirror 13, the rotation position of the mirror 13 and the rotation position of the mirror 15 correspond one-to-one. Therefore, the irradiation position on the PSD 106 light receiving surface of the servo laser light reflected by the mirror 15 corresponds to the rotation position of the mirror 15, that is, the scanning position of the scanning laser light in the target area.

  4A is a diagram schematically illustrating a scanning state of the scanning laser light in the target region, and FIG. 4B is a diagram schematically illustrating a scanning state of the servo laser light on the PSD light receiving surface. is there.

  As shown in FIG. 4A, the scanning laser beam is first scanned in the horizontal direction (X-axis direction) along the uppermost line (scanning line 1) in the target region. When the scanning of this line is completed, the line (scanning line 2) one step below in the vertical direction (in the Y-axis direction) is scanned in the horizontal direction. This scanning operation is repeated over a plurality of preset stages (five stages in the figure). When the scanning of the lowermost line (scanning line 5) is completed, the process returns to the uppermost stage (scanning line 1) and the same scanning is repeated.

  When the scanning laser beam is scanned in this manner, the servo laser beam scans on the light receiving surface of the PSD 106 accordingly. That is, as shown in FIG. 4B, the servo laser light draws a scan trajectory corresponding to the scan trajectory of the scanning laser light on the light receiving surface of the PSD 106. In the figure, the dotted line arrows indicate the scan trajectory of the servo laser beam corresponding to each scan line in FIG.

  Returning to FIG. 2, the current signal related to the scan position of the scanning laser beam is input from the PSD 106 to the control processing unit 202. Based on the current signal from the PSD 106, the control processing unit 202 drives and controls the mirror actuator 100 so that the scanning laser passes through an appropriate scan trajectory (see FIG. 4A) within the target region. In order to use for this control, a target value table 202 a is provided in the control processing unit 202.

  The target value table 202a includes data (on the PSD light receiving surface) based on the output value of the PSD 106 when the servo laser light is positioned at a predetermined position (sample point) on the ideal trajectory shown in FIG. Is stored). FIG. 5 is a diagram schematically showing the relationship between the scanning locus of servo laser light and sample points. In the figure, the solid line arrow indicates the ideal trajectory of the servo laser light on the light receiving surface of the PSD 106 when the scanning laser light appropriately scans the target area (see FIG. 4A). These coordinate data serve as target values when the scanning laser beam is scanned within the target area, and are acquired by performing verification or the like in advance.

  During the scanning operation by the scanning laser beam, the control processing unit 202 makes the scan trajectory on the PSD light-receiving surface into a trajectory defined by the coordinate data (target value) in the target value table 202a based on the current signal from the PSD 106. A control signal is output to the actuator driving unit 203 so as to be pulled. The actuator driving unit 203 drives the mirror actuator 100 based on this control signal. By such servo operation, the scanning laser beam is scanned in an appropriate trajectory within the target area.

  In addition, the control processing unit 202 outputs a control signal for driving the semiconductor lasers 101 and 104 to the laser driving unit 204. The laser driving unit 204 drives the semiconductor lasers 101 and 104 based on this control signal.

  The control processing unit 202 monitors the convergence position of the servo laser light on the PSD light-receiving surface during the scanning operation of the scanning laser light. When this convergence position reaches a position set in advance as a position for detecting obstacles and detecting distance (hereinafter referred to as “ranging position”), the output of the semiconductor laser 101 is output for a certain period at this timing. A control signal for increasing the power only to the laser drive unit 204 is output. As a result, pulsed high-power laser light (hereinafter referred to as “pulse laser light”) is emitted from the semiconductor laser 101 at each distance measurement position.

  When this pulsed laser beam is reflected by an obstacle and received by the PD 108, an electric signal based on this is input to the control processing unit 202. Thereby, the control processing unit 202 detects the presence of an obstacle. Further, the control processing unit 202 measures the distance to the obstacle based on the emission timing of the pulse laser beam and the light reception timing by the PD 108.

  By the way, the output value from the PSD 106 is easily affected by temperature change and secular change. That is, even if the servo laser beam converges at the same position on the PSD light receiving surface, the output value may vary due to the temperature of the PSD 106 being different. Further, when the usage period of the device becomes long, the output value from the PSD 106 may deviate from the value at the initial operation even under the same temperature condition. Due to these factors, it can be assumed that the output value of the PSD 106 at the same convergence position is different between when the coordinate data of the target value table 202a is acquired and during the actual scanning operation. However, in this case, the servo operation using the output value of the PSD 106 and the coordinate data of the target value table 202a is not properly performed.

  Therefore, in the present embodiment, when there is a possibility that the output value of the PSD 106 is shifted due to a temperature change, a secular change, or the like, the coordinate data in the target value table 202a is calibrated to the current state, and the target after calibration is corrected. Servo operation is performed using the value table 202a.

  FIG. 6 is a diagram showing a configuration for performing data calibration of the target value table 202a in the laser radar. In the figure, the configuration for scanning the target area is omitted.

  In addition to the configuration described above, the beam irradiation head 201 includes a temperature detector 109, a semiconductor laser 110 for calibration, a first light receiver 111, and a second light receiver 112.

  The temperature detector 109 is disposed in the vicinity of the PSD 106. By detecting the ambient temperature of the PSD 106 by the temperature detector 109, the temperature of the PSD 106, particularly the light receiving surface thereof, is indirectly detected. A detection signal from the temperature detector 109 is input to the control processing unit 202.

  The first and second light receivers 111 and 112 are for detecting two reference positions (first reference position and second reference position) for calibrating coordinate data set in the mirror actuator 100, respectively. is there. The first and second light receivers 111 and 112 are arranged with a predetermined distance in the Z-axis direction of FIG. 6 with respect to the reflecting surface 15a of the mirror 15. Further, as shown in FIG. 7, the first and second light receivers 111 and 112 are arranged at diagonal positions with the mirror 15 in between when the mirror actuator 100 is viewed from the Z-axis direction of FIG. ing. The first and second light receivers 111 and 112 are screwed to the housing (not shown) of the beam irradiation head 201 or the like by UV bonding so that the first and second light receivers 111 and 112 do not easily move due to vibrations during traveling of the passenger car. It is firmly fixed. The first and second light receivers 111 and 112 output an electrical signal corresponding to the intensity of light received by the light receiving surface. This electrical signal is input to the control processing unit 202.

  When the actuator 100 is driven to the first reference position under the state at the time of setting the target value table 202a (hereinafter referred to as “initial state”), the servo laser beam is the first shown in FIG. When the position of the reference point R1 is irradiated and the actuator 100 is driven to the second reference position, the servo laser light is irradiated to the position of the second reference point R2 shown in FIG. The first reference point R1 and the second reference point R2 are substantially diagonal with respect to the substantially rectangular scan area on the light receiving surface of the PSD 106. In the target value table 202a, coordinate data corresponding to the first reference point R1 and the second reference point R2 is stored in addition to the coordinate data for the scan control.

  Returning to FIG. 6, the semiconductor laser 110 is driven by the laser driving unit 204. Laser light (hereinafter referred to as “position detection laser light”) is emitted from the semiconductor laser 110 in the Z-axis direction in FIG. 6 and in the direction opposite to the emission direction of the servo laser light. The emitted laser beam for position detection is reflected by the reflecting surface 15 a of the mirror 15.

  When the mirror actuator 100 comes to the first reference position, the position detection laser light reflected by the reflecting surface 15a enters the first light receiver 111, and the amount of light received by the first light receiver 111 is maximized. When the mirror actuator 100 comes to the second reference position, the position detection laser beam reflected by the reflecting surface 15a enters the second light receiver 112, and the amount of light received by the second light receiver 112 is maximum. Become. That is, the first reference position and the second reference position of the mirror actuator 100 (mirror 13 and mirror 15) are detected by detecting that the amount of light received by the first and second position detectors 111 and 112 is maximum. Detected.

  When the coordinate data is calibrated, the control processing unit 202 drives the semiconductor lasers 104 and 110 and drives the mirror actuator 100 two-dimensionally in the vicinity of the first reference position. As a result, the servo laser light is scanned on the light receiving surface of the PSD 106 in the vicinity of the first reference point R1. The control processing unit 202 stores the output value (coordinate data) of the PSD 106 when the amount of light received by the first light receiver 111 becomes maximum during the scanning operation.

  Next, the control processing unit 202 drives the mirror actuator 100 in the vicinity of the second reference position, and similarly scans the servo laser light in the vicinity of the second reference point R2. Then, during this scanning operation, the output value (coordinate data) of the PSD 106 when the amount of light received by the second light receiver 112 becomes maximum is stored.

  If the state of the PSD 106 in the actual operation is the same as the initial state, the two coordinate data stored in the calibration operation in this way are equal to the coordinate data of the first reference point R1 and the second reference point R2. Therefore, in this case, the control processing unit 202 does not calibrate the coordinate data in the target value table 202a.

  On the other hand, when the state of the PSD 106 changes from the initial state due to the influence of temperature change, secular change, etc., the two coordinate data stored at the time of the calibration operation are the first reference point R1 and the second reference point. This is different from the coordinate data of R2. That is, assuming that the coordinate points corresponding to the two coordinate data stored at the time of calibration are the first reference point R1 ′ and the second reference point R2 ′, respectively, as shown in FIG. R1 ′ and the second reference point R2 ′ are shifted from the first reference point R1 and the second reference point R2. In this case, the control processing unit 202 calibrates the target value table 202a by performing processing equivalent to the following, and performs a servo operation using the calibrated target value table.

  That is, the horizontal shift amount ΔP1 and the vertical shift amount ΔQ1 between the first reference point R1 ′ and the first reference point R1 are calculated, and the second reference point R2 ′ and the first reference point R2 are calculated. A horizontal shift amount ΔP2 and a vertical shift amount ΔQ2 are calculated. Next, an average value of the deviation amount in the horizontal direction (ΔP1 + ΔP2) / 2 and an average value of the deviation amount in the vertical direction (ΔQ1 + ΔQ2) / 2 are obtained, and these are added as correction values to each coordinate data of the target value table 202a. A new target value table 202a is generated. Then, the servo operation is performed using the generated target value table 202a.

  As described above, the coordinate data in the target value table 202a is calibrated in accordance with the temperature change, aging change, etc., and the calibrated target value table is used for the servo operation. High servo operation can be performed.

  In the present embodiment, the calibration operation of the target value table 202a can be performed according to the flowchart shown in FIG. The following operation is performed under process control in the control processing unit 202.

  When the obstacle detection operation is started in the laser radar, first, data correction of the target value table 202a is performed as described with reference to FIG. 8B (S1). When such data calibration is completed, the scanning operation of the scanning laser beam in the target area is started (S2). This scanning operation is performed using the target value table calibrated in S1.

  During the scanning operation, the temperature of the PSD 106 is monitored based on the detection signal from the temperature detector 109. That is, it is determined whether the temperature detected by the temperature detector 109 exceeds a preset temperature T (for example, 50 ° C., 60 ° C., 70 ° C.,...) From the temperature at the start of the scanning operation. (S3). If the detected temperature does not exceed the set temperature T (S3: NO), the scan operation is continued unless the scan operation is terminated due to other factors (power off, etc.) (S5: NO).

  On the other hand, if it is determined that the temperature detected by the temperature detector 109 exceeds the set temperature T (for example, 50 ° C.) (S3: YES), the scanning operation is stopped (S4), and the target value table data calibration is performed again. (S1). When the data calibration is completed, the scanning operation is resumed based on the target value table after calibration (S2).

  Thereafter, the temperature of the PSD 106 is continuously monitored. Then, it is determined whether or not the temperature detected by the temperature detector 109 exceeds the next set temperature T (for example, 60 ° C.) (S3). If it is determined that the detected temperature has exceeded the next set temperature T (S3: YES), the scan operation is stopped (S4), the target value table data calibration is performed (S1), and the calibration is performed. The scanning operation is resumed based on the target value table (S2).

  If another factor for ending the scan operation occurs during the scan operation (S5: YES), the scan operation is stopped and the obstacle detection operation is ended.

  As described above, in the above-described embodiment, when the output value of the PSD 106 changes due to temperature change or aging change, the coordinate data of the target value table 202a used for the servo operation of the mirror actuator 100 is converted into the PSD 106. Since the calibration is performed in accordance with the change in the output value, a highly accurate servo operation can be performed. Thereby, the scanning operation within the target region by the scanning laser beam can be performed with high accuracy.

  Further, since the first reference position and the second reference position of the mirror actuator 100 are detected using the semiconductor laser 110 (semiconductor laser 101) and the first and second light receivers 111 and 112, the mirror actuator The detection can be performed in a non-contact state with 100, and an extra load can be prevented from being applied to the mirror actuator 100.

  Furthermore, in this embodiment, data calibration is performed each time an obstacle detection operation is started, so that it is possible to further prevent deterioration in accuracy of the scanning operation due to secular change.

  Furthermore, in the present embodiment, since the data calibration is performed when the temperature detected by the temperature detector 109 is such that the output value of the SD 106 is affected, the data calibration is performed at an appropriate timing. be able to. Therefore, it is possible to prevent the scan operation performed for detecting the obstacle from being frequently interrupted for data calibration while preventing the deterioration of the accuracy of the scan operation due to the temperature change, thereby ensuring safety.

  Note that output fluctuations in the PSD 106 are not uniform at all positions on the light receiving surface, and there is a high possibility that the way of fluctuation is usually different for each position. Therefore, in the calibration of the target value table 202a, in consideration of such fluctuation variation, as many reference points as possible are set on the light receiving surface, and fluctuation values at each reference point (ΔP1, ΔQ1, and ΔP2 in FIG. 8B) are set. , ΔQ2) may be desirable based on the average value. However, when a large number of reference points are set on the light receiving surface, the reference position of the actuator 100 increases accordingly, and as a result, the number of photodetectors for detecting each reference point also increases. For this reason, if too many reference points are set on the light receiving surface, the number of parts increases, resulting in a complicated configuration and an increase in cost.

  In contrast, in the present embodiment, the first reference point R1 and the second reference point R2 are set at two diagonal positions on the light receiving surface of the PSD 106, and a change in the output value is detected at these reference points. As a result, it is possible to perform a calibration process that takes into account variations in the output value depending on the position on the light receiving surface while suppressing the increase in the number of parts such as photodetectors by reducing the number of detection points as much as possible.

  In addition, the laser radar of this Embodiment can be mounted in moving bodies, such as a passenger car, for example.

  FIG. 10 is a diagram showing a configuration when a laser radar is mounted on a passenger car. Detection signals are input to the control processing unit 202 from a key position detector 301 and a speed detector 302 provided on the passenger car side. The key position detector 301 detects whether or not an ignition key for starting the engine is at a position for starting the engine. If the ignition key comes to the position for starting the engine, it can be determined that the engine has started. The speed detector 302 detects the speed of the passenger car.

  FIG. 11 is a flowchart showing an example of the calibration operation when the laser radar is mounted on a passenger car. The following operation is performed under process control in the control processing unit 202.

  Based on the input from the key position detector 301, it is determined whether or not the engine of the passenger car has been started (S11). When it is determined that the engine has started, an obstacle detection operation is started.

  First, as described with reference to FIG. 8B, data correction of the target value table 202a is performed (S12). When the data calibration is completed, a scanning operation is started (S13). This scanning operation is performed using the target value table calibrated in S12.

  Next, it is determined whether or not the temperature detected by the temperature detector 109 exceeds a preset temperature T (for example, 50 ° C., 60 ° C., 70 ° C.,...) From the temperature at the start of the scanning operation. (S14). When it is determined that the detected temperature has exceeded the set temperature T (for example, 50 ° C.) (S14: YES), it is determined whether or not the speed of the passenger vehicle has stopped based on the input from the speed detector 302. (S15). If the passenger car is traveling (S15: NO), the data calibration of the target value table 202a is not performed and the apparatus is on standby.

  When the passenger car stops, for example, temporarily stops waiting for a signal (S15: YES), the scanning operation is stopped (S16), and data calibration of the target value table 202a is performed again (S12). When the data calibration is completed, the scanning operation is restarted based on the target value table after calibration (S13).

  Thereafter, the temperature of the PSD 106 is continuously monitored. When it is determined that the temperature detected by the temperature detector 109 has exceeded the next set temperature T (for example, 60 ° C.) (S14: YES), in the same manner as described above, a speed stop (S15: YES) is waited. The scanning operation is stopped (S16), and data calibration is performed (S12).

  During the scanning operation, it is determined whether or not the engine is stopped based on the input from the key position detector 301 (S17). If it is determined that the engine has stopped (S17: YES), the scanning operation is stopped and the obstacle detection operation is ended.

  As described above, in the flowchart of FIG. 11, since the data calibration of the target value table is performed every time the engine is started, that is, every time the obstacle detection operation is started, it is possible to prevent deterioration in the accuracy of the servo operation due to secular change. .

  In the flowchart of FIG. 11, data calibration is performed at a temperature at which the output value of the PSD 106 is affected. Therefore, it is possible to prevent deterioration in accuracy of the servo operation due to a temperature change.

  Further, in the flowchart of FIG. 11, since the data calibration is not performed unless the speed is stopped, the scanning operation for detecting the obstacle is not interrupted by the calibration operation while the passenger car is running, and the safety is ensured. Sex is secured.

  Next, a modified example of the beam irradiation head 201 will be described with reference to FIG. In this modified example, as shown in FIG. 12A, in the mirror actuator 100, a refractive element 50 is provided instead of the mirror 15. The refractive element 50 is made of, for example, acrylic or glass. The condensing lens 105 and the PSD 106 are disposed on the opposite side of the semiconductor laser 104 with the refractive element 50 interposed therebetween.

  The servo laser light emitted from the semiconductor laser 104 is incident on the refraction element 50 and receives the refraction action of the refraction element 50 as shown in FIG. Thereafter, the servo laser light that has passed through the refractive element 50 is received by the PSD 106 via the condenser lens 105. At this time, when the refraction element 50 rotates, the irradiation position on the PSD 106 is displaced by the refraction action.

  In this modified example, as shown in FIG. 5B, the scanning semiconductor laser 101 is also used as the calibration semiconductor laser. In this case, as shown in FIG. 13, the first light receiver 111 and the second light receiver 112 are paired with the mirror 13 interposed when the mirror actuator 100 is viewed from the Z-axis direction in FIG. Arranged at the corner position. Here, the first light receiver 111 and the second light receiver 112 are arranged at positions that do not block the scanning laser light even if the scanning laser light is scanned within the target area when the obstacle is detected. Has been.

  The semiconductor laser 101 has a considerably higher emission power than the calibration semiconductor laser 110 in FIG. If such high-power laser light is directly incident on the first and second light receivers 111 and 112, the first and second light receivers 111 and 112 may be damaged. Therefore, filters 113 and 114 for attenuating the laser light are disposed in front of the light receiving surfaces of the first and second light receivers 111 and 112, respectively. Thus, in the calibration operation, the laser beam from the semiconductor laser 101 is used as the position detection laser beam. Of course, it is desirable that the emission power of the semiconductor laser 101 during the calibration operation is kept as low as possible with respect to the emission power when scanning the target area.

  In this way, if the scanning semiconductor laser 101 can be used as the calibration semiconductor laser 110, the configuration can be simplified.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the embodiments of the present invention can be variously modified in addition to the above.

  For example, in the above embodiment, the first reference point R1 and the second reference point R2 used for data calibration of the target value table 202a are set as the servo laser light during the obstacle detection operation as shown in FIG. However, these reference points may be set within the orbital region of the servo laser beam. However, in the modified example shown in FIG. 12, it is necessary to arrange the first and second light receivers 111 and 112 at positions that do not block the scanning laser beam when detecting an obstacle. It is necessary to set a reference point on the PSD light receiving surface. For this reason, in this modified example, the first reference point R1 and the second reference point R2 are inevitably set outside the trajectory region of the servo laser light.

  In the above-described embodiment, the first reference position and the second reference position of the mirror actuator 100 are set so that the semiconductor laser 110 for calibration (or the semiconductor laser 101 is also used) and the first and second light receivers 111 and 112. However, the reference position may be detected by another detector such as a non-contact detection switch using a micro switch.

  Furthermore, in the configuration example of FIG. 11 described above, the engine start is determined based on the signal from the key position detector 301, and the speed stop is determined based on the signal from the speed detector 302. It is good also as a structure which receives the information of engine starting, and the information of speed stop from the control part.

  Further, in the configuration example of FIG. 11 described above, the data calibration is performed by detecting the start of the passenger car engine. However, the calibration may be performed so that the data calibration is performed at the timing of starting the detection operation. It is also possible to adopt a configuration in which data calibration is performed at the timing when the power is turned on.

  Further, in the above embodiment, the temperature of the PSD 106 is indirectly detected by detecting the ambient temperature of the PSD 106 by the temperature detector 109. This is because in the above embodiment, it is difficult to directly detect the temperature by directly attaching the temperature detector 109 to the PSD 106. However, if possible, the temperature detector 109 may be directly attached to the PSD 106 to directly detect the temperature, or the temperature is directly detected using a contact-type temperature detector. You may do it. Various other methods can be used as a method of detecting the temperature of the PSD 106.

  Furthermore, although the above-described embodiment is an application of the present invention to an in-vehicle laser radar, the present invention can also be applied to a laser radar for other uses, for example, for measuring aerosol in the atmosphere. Is possible. In the above embodiment, a semiconductor laser is used as a light source for emitting laser light used for servo and data calibration. However, other light sources such as an LED (Light Emitting Diode) may be used instead.

  In addition, the embodiment of the present invention can be variously modified as appropriate within the scope of the technical idea shown in the claims.

The figure which shows the structure of the mirror actuator which concerns on embodiment The figure which shows the structure of the laser radar which concerns on embodiment The figure which shows the structure of PSD which concerns on embodiment The laser radar which concerns on embodiment WHEREIN: The figure which shows the scanning state of the scanning laser beam in a target area | region, and the scanning state of the servo laser beam on a PSD light-receiving surface The figure which shows typically the relationship between the scanning miracle of a servo laser beam, and a sample point in the laser radar which concerns on embodiment. The figure which shows the structure for performing the data calibration of the target value table in the laser radar which concerns on embodiment The figure which shows arrangement | positioning of the 1st, 2nd light receiver which concerns on embodiment The figure for demonstrating the data calibration of the target value table which concerns on embodiment The flowchart which shows an example of the timing of the calibration operation | movement of the target value table in the laser radar which concerns on embodiment The figure which shows the structure relevant to the laser radar in case the laser radar which concerns on embodiment is mounted in a passenger car The flowchart which shows an example of the timing of calibration operation in case the laser radar which concerns on embodiment is mounted in a passenger car The figure which shows the modification of the beam irradiation head which concerns on embodiment The figure which shows arrangement | positioning of the 1st, 2nd light receiver in the modification of the beam irradiation head which concerns on embodiment. The figure explaining the position detection method using a photorefractive element and a mirror

Explanation of symbols

13 Mirror (Detection light displacement part)
15 Mirror (servo light displacement part, detection light displacement part)
50 Refraction element (servo light displacement part)
100 mirror actuator (actuator)
101 Semiconductor laser (light source)
106 PSD (light receiving position detector)
109 Temperature detector (temperature detector)
110 Semiconductor laser (position detection light source)
DESCRIPTION OF SYMBOLS 111 1st light receiver 112 2nd light receiver 113 Filter 114 Filter 202 Control processing part (drive control part, orbit information calibration part)
202a Target value table (trajectory information storage unit, reference position storage)

Claims (6)

An actuator for scanning a scanning laser beam in a two-dimensional direction;
A drive control unit for driving and controlling the actuator;
A servo light displacement unit that changes a traveling direction of the servo light in accordance with driving of the actuator;
A light receiving position detector that receives the servo light and outputs a signal corresponding to the light receiving position;
A trajectory information storage unit that stores trajectory information related to the ideal trajectory of the servo light on the light receiving position detector when the scanning laser light appropriately scans the target area;
A reference position storage unit that stores reference information related to a reference light receiving position of the servo light on the light receiving position detector when the actuator is positioned at a predetermined specific position;
A specific position detector for detecting that the actuator is at the specific position;
Based on an output signal from the light receiving position detector when the specific position detecting unit detects that the actuator is at the specific position and the reference information stored in the reference position storage unit, the trajectory information is obtained. It has a track information calibration section that calibrates it to the current situation,
The drive control unit controls the actuator so that the scanning laser beam scans the target area based on an output signal from the light receiving position detector and the trajectory information calibrated by the trajectory information calibration unit. ,
A beam irradiation apparatus characterized by that. The beam irradiation apparatus according to claim 1,
The specific position detector detects a first specific position and a second specific position;
The first specific position and the second specific position are such that the light receiving position of the servo laser beam on the light receiving position detector when the actuator is at the specific position is on the light receiving surface of the light receiving position detector. Set to be almost diagonal,
A beam irradiation apparatus characterized by that. The beam irradiation apparatus according to claim 2, wherein
The specific position detector is
A position detection light source that emits position detection light;
A detection light displacement section that changes a traveling direction of the position detection light in accordance with driving of the actuator;
A first light receiver for receiving the position detection light when the actuator is at the first specific position;
A second light receiver that receives the position detection light when the actuator is in the second specific position;
A beam irradiation apparatus characterized by that. In the beam irradiation apparatus of Claim 3,
A light source that emits the scanning laser light is also used as the position detection light source, and a filter that attenuates light intensity is disposed in front of the first light receiver and the second light receiver.
A beam irradiation apparatus characterized by that. In the beam irradiation apparatus of any one of Claim 1 to 4,
A temperature detector for detecting the temperature of the light receiving position detector;
The drive control unit drives the actuator in the vicinity of the specific position when the temperature detected by the temperature detection unit reaches a preset temperature,
The trajectory information calibration unit calibrates the trajectory information according to the driving of the actuator in the vicinity range.
A beam irradiation apparatus characterized by that. In the beam irradiation apparatus of any one of Claim 1 to 5,
The drive control unit refers to speed information of a moving body on which the beam irradiation device is mounted, and controls the actuator so that the scanning laser beam scans the target area when the moving body is in a moving state. Driving the actuator in the vicinity of the specific position when the moving body is in a stopped state;
The trajectory information calibration unit calibrates the trajectory information according to the driving of the actuator in the vicinity range.
A beam irradiation apparatus characterized by that.

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