JP2008191099A - Light projection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light projection device for an optical radar capable of adjusting easily scanning amplitude and an optical axis of a projection optical axis, and acquiring high adjustment accuracy. <P>SOLUTION: A projection direction of a beam radiated from a laser diode 31 is set by a projection lens 37. The position of the projection lens 37 is detected by position detectors 43a, 43b. The projection direction of the beam is converted into a position of the projection lens 37 by a scanner control part 25. Driving of an actuator 40 is controlled by the scanner control part 25 based on a target position of the projection lens 37 acquired by the scanner control part 25 and on a detected position of the projection lens 37 detected by the position detectors 43a, 43b. A deviation of the projection direction of the light projection device in a specific target projection direction of the beam is stored as a correction value in a memory 53 in the scanner control part 25, corrected by the correction value, and converted into a position of the projection lens 37. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention generates a light beam from a light source such as a laser beam, receives reflected light from a target object, and detects the distance from the target object. The present invention relates to a direction control device and an optical axis adjustment method.

  In recent years, efforts have been made to develop technologies aimed at improving driver safety when driving a car. As one of the means, an apparatus for detecting position information of an object existing in front of a preceding vehicle and an automobile using a radar has been put into practical use. Specifically, based on the position detection information of the vehicle front object obtained by the radar device, safety support such as collision avoidance with the vehicle ahead is performed during traveling.

  Various radar systems have been proposed at present, and it is required that sufficient detection performance be obtained while suppressing apparatus costs. Among them, an optical radar device that scans a laser beam and detects an object has been put into practical use.

  For example, as a light radar projector, as disclosed in Patent Document 1 below, laser light is scanned at a predetermined angle and projected toward a front object, and reflected light generated by the object is detected by a light receiver. There has been proposed an apparatus for calculating the position of a front object by detecting a time difference from projection to detection of received light.

  FIG. 8 is a block diagram showing a configuration of a conventional optical radar device described in Patent Document 1 below.

  In FIG. 8, the object detection apparatus 1 includes a light projecting unit 2, a light receiving unit 3, an offset position storage circuit 5, and a CPU 4 to which a plurality of tilt sensors 6 are connected. Then, the light that is driven by the oscillation circuit 11 in the light projecting unit 2 and is emitted from the light emitting element 12 is moved in the horizontal or vertical direction by the lens 13, the actuator 14, and the actuator (ACT) driving circuit 15. Change the direction of the projected light.

The CPU 4 gives an instruction of an actuator driving amount necessary for moving the lens 13 to a position corresponding to the projection direction. The lens 13 is scanned by giving an instruction to the ACT driving circuit 15 to sequentially increase or decrease the driving amount of the actuator 14. During scanning of the projection lens 13, projection light is output from the light emitting element 12 via the oscillation circuit 11 from the CPU 4. The reflected light is detected by the light receiving lens 17, the light receiving element 18, and the detection circuit 19 to detect the object.
JP 2002-162470 A

  The above-described light projecting device of a radar apparatus is a method of continuously scanning an outgoing beam by continuously moving a projection lens to a position corresponding to a target projection direction, and emitting a light beam at regular intervals. It is. In the light projecting device in the radar device of Patent Document 1, the projection lens position and the corresponding emission beam angle are estimated from the actuator drive instruction. For this reason, it is impossible to detect and control the projection lens position that actually exists in real time and correct the projection lens position.

  In the case of the configuration of FIG. 8, when the temperature change and the change with time occur in the movement amount sensitivity characteristic of the actuator 14, the movement amount of the lens 13 with respect to the drive instruction amount changes. Since correction control is not performed, a deviation occurs between the projection direction instructed by the CPU 4 and the direction of light actually projected. Therefore, in the conventional light projecting device of the radar device, even if the optical axis of the projection light is adjusted, even if the adjustment deviation due to the temperature change of the actuator sensitivity or the change with time occurs, it cannot cope. It was.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light radar projection device that can easily adjust the scanning amplitude and optical axis of the projection optical axis and obtain high adjustment accuracy. Is to provide.

  That is, the invention described in claim 1 is an optical radar projector that detects an object by scanning a light beam emitted from a first light source and receiving reflected light from the object. An optical element that sets a projection direction of a light beam emitted by one light source, a position detector that detects a position of the optical element, a conversion unit that converts the projection direction of the light beam into a position of the optical element, and the optical An actuator for moving the element, a drive control means for controlling the drive of the actuator based on the target position of the optical element obtained by the conversion means and the detection position of the optical element detected by the position detector And an adjustment value storage means for storing an adjustment value for correcting a deviation of the direction in which the light is projected by the light projecting device with respect to a specific target projection direction of the light, and the conversion means includes a projection method. The corrected by the correction value and converting the position of the optical element.

  According to the first aspect of the present invention, it is possible to easily adjust the scanning center angle and the scanning amplitude by performing feedback control of the projection lens position and instructing an offset by position adjustment.

  According to a second aspect of the present invention, in the first aspect of the invention, the specific target direction of the light beam is an angle corresponding to an origin and a maximum swing width.

  According to the second aspect of the invention, the offset adjustment value in the two-dimensional projection direction and the amplitude adjustment value are held in the storage unit, so that the direction of the scanning origin and the amplitude of the projection angle are always set. Can be held constant.

  According to a third aspect of the present invention, in the first aspect of the invention, the position detecting means includes a second light source, a position detecting element, and a slit that moves in conjunction with the optical element. The detection output of the optical element position is obtained.

  According to the third aspect of the present invention, by constantly detecting the actual position of the projection optical element, the projection optical element can be controlled to follow the position corresponding to the target projection direction. Without receiving it, the adjustment accuracy of the projection angle can be improved.

  According to a fourth aspect of the present invention, there is provided a first light source that emits a predetermined light beam, a movable optical element for setting a projection direction of the light beam emitted from the first light source, and the optical element. An actuator that moves two-dimensionally in a direction perpendicular to the optical axis direction of the first light source, position detection means for detecting the position of the optical element, and the optical element based on the projection direction of the light beam Calculating means for calculating a target position to move the optical element, and a deviation of a projection direction of the light beam emitted from the first light source with respect to a specific target projection direction of the light beam, the optical element calculated by the calculation unit Drive control means for controlling the drive of the actuator to correct based on the target position and the detected position of the optical element detected by the position detector.

  According to the fourth aspect of the present invention, it is possible to easily adjust the scanning center angle and the scanning amplitude by performing feedback control of the position of the projection optical element and giving an offset instruction by position adjustment.

  According to a fifth aspect of the present invention, in the fourth aspect of the present invention, a deviation of a projection direction of a light beam emitted from the first light source with respect to a specific target projection direction of the light beam is stored as an adjustment value. Adjustment value storage means, and the drive control means includes a target position of the optical element calculated by the calculation means, a detection position of the optical element detected by the position detector, and the adjustment value. The driving of the actuator is controlled based on the adjustment value stored in the storage means.

  According to the fifth aspect of the present invention, by holding the offset adjustment value and the amplitude adjustment value in the two-dimensional projection direction in the storage unit, the direction of the scanning origin and the amplitude of the projection angle are always set. Can be held constant.

  According to a sixth aspect of the present invention, in the fourth aspect of the present invention, the specific target direction of the light beam is an angle corresponding to an origin and a maximum swing width.

  According to the sixth aspect of the invention, by holding the offset adjustment value and the amplitude adjustment value in the two-dimensional projection direction in the storage means, the direction of the scanning origin and the amplitude of the projection angle are always set. Can be held constant.

  According to a seventh aspect of the present invention, in the invention according to the fourth aspect, the position detecting means includes a second light source that emits a light beam different from the first light source, a position detecting element, and the A slit that moves in conjunction with the movement of the optical element; and a position detection element that receives the light beam emitted from the second light source through the slit and detects the position of the optical element. And

  According to the seventh aspect of the invention, since the projection lens can be controlled to follow the position corresponding to the target projection direction by always detecting the actual position of the projection optical element, it is affected by the change in the actuator sensitivity characteristic. Therefore, the adjustment accuracy of the projection angle can be improved.

  According to the present invention, it is possible to provide an optical radar projector that can easily adjust the scanning amplitude and optical axis of the projection optical axis and obtain high adjustment accuracy.

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

  FIG. 1 shows an embodiment of the present invention, and is a block diagram showing the overall structure of a laser radar to which the light projecting device of the present invention is applied.

  In FIG. 1, this laser radar forms a light output of a laser control unit 21 that controls the operation of the entire laser radar and a laser diode 31 that is a light emitting element into a beam, and lenses 32 and 33 that are optical elements. And 37, the scanner unit 24 that projects the beam at an arbitrary angle, the output of the position detector of the scanner unit 24 and the target angle indicated by the laser control unit 21 are compared to control the amount of movement of the lens. The scanner control unit 25, a light receiving unit 27 that detects reflected light from the target object 62, and a laser light emitting device 23 that controls the light emitting operation of the laser diode 31 are configured.

  The laser control device 21 instructs to emit light to the laser light emitting device 23, detects reflected light from the target object 62 in the light receiving unit 27, instructs the target angle of the beam projection direction to the scanner control unit 25, and angle offset. An instruction signal is output and a movement completion signal of the scanner unit 24 is input.

  The scanner unit 24 supports a laser diode 31 and relay lenses 32 and 33 fixed in the lens holder 30 and a projection lens 37 for scanning light projected from the laser diode 31 as a first light source. A member 36, a plurality of wire springs 35 connecting the lens holder 30 and the support member 36, and driven members 38 a and 38 b on both sides of the support member 36 for moving the projection lens 37 together with the support member 36. An actuator 40 that directly moves the driven members 38a and 38b, and light sources 41a and 41b and position detectors 43a and 43b, which are second light sources for detecting the positions of the driven members 38a and 38b. Composed.

  In the scanner unit 24, relay lenses 32 and 33 are used to shape the light output from the laser diode 31 into a beam suitable for a laser radar having an appropriate divergence angle. The laser diode 31 emits light by driving the laser light emitting device 23 in accordance with a laser light emission command from the laser control unit 21. The beam projected from the laser diode 31 through the relay lenses 32 and 33 is further projected to the outside of the laser radar through the projection lens 37 mounted on the support member 36.

  The support member 36 is moved in the two-dimensional direction of the horizontal direction (X direction) and the vertical direction (Y direction) together with the driven members 38a and 38b by the actuator 40. Thereby, since the projection lens 37 mounted on the support member 36 is moved in the two-dimensional direction, the beam refracted by the projection lens 37 can be scanned two-dimensionally.

  The driven members 38a and 38b are formed with two slits 39a and 39b extending in the X direction and the Y direction, respectively. Light sources 41a and 41b and position detectors 43a and 43b are disposed on both sides of the driven members 38a and 38b with the slits 39a and 39b interposed therebetween. Although not shown, the position detectors 43a and 43b are composed of photoelectric conversion elements such as PSD (Position Sensing Device) and divided photodiodes.

  The movement of the support member 36 by the actuator 40 is detected by two position detectors provided independently, a position detector 43a that detects movement in the X direction and a position detector 43b that detects movement in the Y direction. And sent to the scanner control unit 25. In this embodiment, since optical position detectors, such as PSD, are used, the light sources 41a and 41b which irradiate each position detector 43a and 43b are arrange | positioned. The light sources 41a and 41b generally use light emitting diodes (LEDs) or laser diodes.

  As shown in FIG. 2, the projection lens 37 and the support member 36 can move in the vertical direction (Y direction) and the horizontal direction (X direction) in a plane perpendicular to the optical axis, and the actuator 40. However, when the projection lens 37 is driven in the direction of moving from the neutral position, a restoring force is applied in the direction opposite to the moving direction by the wire spring 35. The projection lens 37 is held at a position where the driving force of the actuator 40 and the restoring force of the wire spring 35 are balanced.

  The projection lens 37 has a characteristic of emitting with a refraction angle proportional to the amount of deviation of the incident position of the light beam with respect to the lens center. Although not shown, the actuator 40 is composed of an electromagnetic actuator such as a boil coil motor, and the driving force is applied in the horizontal and vertical directions by the attraction and repulsion action of the magnetic field generated by the current supplied to the electromagnetic coil and the magnetic field by the permanent magnet. Arise.

  On both side surfaces of the support member 36 of the projection lens 37, the driven members 38a and 38b are disposed as described above, and slit-shaped light guide members (slits) 39a and 39b are formed, respectively. The 2nd light sources 41a and 41b are arrange | positioned in the position used as the front of each slit 39a and 39b. Light rays emitted from the second light sources 41a and 41b enter the slits 39a and 39b, and the transmitted light rays 42a and 42b enter the position detectors 43a and 43b, respectively.

  As the projection lens 37 moves, the center positions of the transmitted lights 42a and 42b of the slits 39a and 39b change, and the incident spot positions on the position detectors 43a and 43b change. The position detectors 43 a and 43 b receive the incident spot light to convert the movement amount of the projection lens 37 into an electrical signal, and output a detection position signal corresponding to the position of the projection lens 37 to the scanner control unit 25. To do.

  The scanner control unit 25, which is a direction control unit, receives a target angle instruction value and an angle offset instruction from the laser control unit 21 and converts them into a movement position of the projection lens 37, and a lens position instruction calculation unit 45 as conversion means (calculation means). A position sensor calculation unit 51 that calculates a movement amount of the projection lens 37 from detection signals of the position detectors 43a and 43b, a position deviation detection unit 46 that detects a shift between the position indication value and the position detection result, and a position shift amount A determination unit 47 for comparing and determining, a linear motor driver 50 that supplies drive power to the actuator 40, a control calculation unit 48 that is a drive control means for giving a drive instruction to the linear motor driver 50 from the amount of positional deviation, and an adjustment value storage It is comprised with the memory 53 which is a means.

  The determination unit 47 is for determining whether or not the positional deviation of the projection lens 37 is within a predetermined range, and outputs the determination result to the laser control unit 21.

  The laser light emitting device 23 turns on and off the laser diode 31 with a predetermined pulse time width according to an instruction from the laser control unit 21. The light beam L1 emitted from the laser diode 31 is transmitted through the relay lenses 32 and 33 to obtain a parallel light beam L2. The parallel light beam L <b> 2 is incident on the projection lens 37, and the projection light 61 that passes through the projection lens 37 is irradiated toward the target object 62. The projection light 61 is a light beam in which the light beam is refracted in the direction of arrow A in FIG. 1 due to the relationship between the optical axis center of the parallel light beam L2 and the incident position of the projection lens 37. By moving in the vertical direction (Y direction), the projection direction of the emitted light is scanned two-dimensionally in the horizontal direction (Ax direction shown in FIG. 2) and the vertical direction (Ay direction shown in FIG. 2).

  The projection light 61 is applied to the target object 62, and the reflected light 63 reflected here is incident on the light receiving lens 55 in the light receiving unit 27, and the light receiving sensor 56, which is a light detection element, changes the reflected light intensity with time. Is detected. Then, the detected light reception detection signal is output to the laser control unit 21.

  Next, the relationship between the moving direction of the projection lens 37 and the direction of the projection light 61 will be described with reference to FIG.

  When the projection lens 37 is translated in the left-right direction (arrow B direction in the figure), the projection direction in the horizontal direction (Ay direction in FIG. 2) can be changed according to the amount of movement. Similarly, when the projection lens 37 is translated in the vertical direction (arrow C direction in the figure), the projection direction in the vertical direction (Ay direction in the figure) can be changed according to the amount of movement.

  The amount of change in projection angle is proportional to the amount of movement of the projection lens 37 left and right and up and down. The target movement amount of the projection lens 37 is calculated from the target projection direction, the projection lens 37 is driven by the actuator 40, and the movement is controlled so as to coincide with the target position, thereby controlling the projection direction.

  The scanning angle in the horizontal and vertical directions is controlled so as to scan within the irradiation range 65 shown in FIG.

  Next, the control timing of the projection lens moving operation and light source emission will be described with reference to the timing chart of FIG.

  FIG. 3 is a timing chart for explaining the projection lens movement control operation and the light source emission control timing of the laser radar in this embodiment.

  In FIG. 3A, the horizontal axis represents time, the vertical axis represents the projection lens position and the corresponding projection angle, and the position control instruction curve E and control during the position control operation of the projection lens 37 of the scanner control unit 25 are controlled. The time change of the position response curve F is shown. FIG. 3A shows the control target position and control position response when the projection lens position is moved to the target lens position 1 and stopped and then moved from the target lens position 1 to the target lens position 2 and stopped. ing.

  The graph of FIG. 3B shows the timing of the movement trigger signal, movement completion signal, projection light emission, and reception signal transmitted and received by the scanner control apparatus. Moreover, the graph of FIG.3 (c) is a graph which expanded and showed a part of graph of FIG.3 (b). The movement trigger signal is a logic signal that is output from the laser control unit 21 to the scanner control unit 25, and starts when the logic of the signal is switched from the “L” level to the “H” level. The position instruction is changed to the target position, and the projection lens 37 is moved to the target position. As for the movement completion signal, the scanner control unit 25 detects the position of the projection lens 37 and sets the “H” level when the deviation from the target position is within a predetermined range, and the “L” level when the deviation is outside the range. The logic signal is output to the laser controller 21.

  When the movement completion signal outputs “H” level, the laser control unit 25 changes the movement trigger signal logic from “H” level to “L” level, assuming that the projection lens position has reached the target position.

  Then, laser pulse emission is performed at the timing shown in FIG. As the light reception signal, a pulse-like signal is detected after a detection time Td from the timing of the laser pulse emission until the reflected light is detected. The detection of laser pulse emission and reflected light is repeated a predetermined number of times. After the light emission and detection are performed a predetermined number of times, the laser control unit 21 instructs the target position of the next projection lens 37 to the lens position 2 (in FIG. 3) to the scanner control unit 25, and a movement trigger signal Is output from the “L” level to the “H” level. Upon receiving the signal, the scanner control unit 25 starts to move from the lens position 1 to the lens position 2.

  When an angle offset instruction is transmitted from the laser control unit 21 to the scanner control unit 25, the position of the projection lens 37 is controlled using a value obtained by adding the angle offset instruction value to the target projection angle instruction as a target instruction. By the above operation, the position control of the projection lens 37 is performed in a state where the optical axis of the outgoing beam is offset by the designated angle.

  In the light projecting device having the above-described configuration, the angle indication value and the actual value are determined by the output offset of the position detectors 43a and 43b, the positional deviation, the optical axis deviation of the laser light source, and the physical angular deviation when the entire apparatus is attached to the automobile. There may be a deviation between the optical axis projected on the screen. However, if the optical axis deviation amount is set in the angle offset instruction value, the center of the scanning angle can be changed, so that the outgoing optical axis deviation can be corrected. Further, by holding the angle offset instruction value in the memory 53, the outgoing optical axis can be controlled in the correct direction when the apparatus is activated.

  Next, a processing operation in which the laser radar of the present embodiment configured as described above scans the projection optical axis will be described with reference to the flowchart of FIG.

  In FIG. 4, the left side is an operation flow of the laser control unit 21, and the right side is an operation flow of the scanner control unit 25. The processes of the laser control unit 21 and the scanner control unit 25 are performed in parallel.

  First, in step S <b> 11, the scanner control unit 25 reads from the memory 53 the origin position correction value and the amplitude correction value of the projection lens 37 corresponding to the correction amount of the outgoing optical axis center deviation. Next, in step S12, a subroutine “projection lens position tracking control” is executed. In this process, an additional value control routine (steps S31 to S35 in the flowchart of FIG. 5), which will be described later, is always performed at regular intervals.

  In the additional value control routine, as shown in the flowchart of FIG. 5, first, in step S31, the current projection lens position is detected, and then in step S32, the amount of deviation from the target position is calculated. In step S33, it is determined whether or not the projection lens position is within a predetermined range. In step S34, the operation amount of the actuator 40 is calculated by the control calculation unit 48 from the calculation result of step S32. Next, in step S35, an instruction is given to the linear motor driver 50 from the result of step S34, and drive output is performed to the actuator 40. As a result, the position of the projection lens 37 is controlled to follow the position instruction value.

  As described above, the subroutine “follow-up control” is executed when the interval interrupt is started in step S1 in the flowchart of FIG. 4 and returns to the original routine when the interval interrupt is released.

  Next, in step S1, a movement angle instruction to be the target projection direction is set, and in step S2, a movement start command (Sig. 1) is transmitted from the laser control unit 21 to the scanner control unit 25. When the command from the laser control unit 21 is received in step S13, the scanner control unit 25 calculates and sets the movement target position instruction from the movement angle instruction in the lens position instruction calculation unit 45 in subsequent step S14. The

  In step S15, a movement amount with respect to the current designated position of the projection lens 37 is calculated from the movement target position instruction, and a movement profile of the movement position instruction value is calculated according to the movement amount. In step S16, the processing result of step S11 is output by the lens position instruction calculation unit 45 as an offset position instruction amount. Next, in step S17, the scanner control unit 25 outputs a position indication value for each fixed time period in accordance with the movement profile calculation result. Then, when the position instruction value coincides with the movement target position in step S18, the process proceeds to step S19 and the position instruction value is fixed to the movement target position.

  In parallel with the processing of steps S17, S18, and S19, the tracking control routine described above (steps S31 to S35 in the flowchart of FIG. 5) is always performed at regular intervals. The position of the projection lens 37 is moved following.

  In step S19, the projection lens 37 is moved to the target position based on the result processed in step S33 (of the flowchart of FIG. 5), and in the subsequent step S20, the position detected by the position sensor calculation unit 51 and the movement are moved. The target position is compared. Then, when the deviation between the two is within the predetermined range, the process proceeds to step S21, and the movement completion signal (Sig. 2) is notified to the laser control unit 21.

  During the process, the laser control unit 21 is in a state of waiting for the movement completion signal (Sig. 2) in step S3. Then, after the movement completion signal is received, the process proceeds to step S4, where the laser diode 31 emits light and the projection light 61 is irradiated. When the projection light 61 is irradiated onto the target object 62, the reflected light 63 enters the light receiving lens 55 of the light receiving unit 27. In step S <b> 5, the light incident on the light receiving lens 55 is detected by the light receiving sensor 56 as an electric signal corresponding to the light intensity.

  On the other hand, in the scanner control unit 25, after the movement completion notification in step S21, the process proceeds to step S22, and the position of the projection lens 37 is controlled to be held at the target position. While this holding control is being performed, the processing result of step S33 described above is confirmed at regular intervals. As a result, in step S23, when the lens position deviation amount is within the predetermined range, the process proceeds to step S24, and a movement completion notification (Sig. 4) is constantly output from the scanner control unit 25 to the laser control unit 21. Is done.

  If it is detected from step S33 that the lens position deviation amount exceeds the predetermined range in step S23, the process proceeds to step S25, and the scanner control unit 25 moves to the laser control unit 21. The lens position deviation instruction (Sig. 5) is notified.

  In step S6, the laser control unit 21 proceeds to step S7 and stops laser emission when the lens position deviation instruction (Sig. 5) is received. Thereafter, the process proceeds to step S3 and waits until a movement completion notification (Sig. 4) is received from the scanner control unit 25 again. On the other hand, in the scanner control unit 25, the processing operations in steps S22 to S26 described above are repeatedly performed until the next movement command is received from the laser control unit 21 in step S26. If the next movement command is received, the process proceeds to step S13, and the subsequent processing operations are repeated.

  Thereafter, in step S6, the laser control unit 21 determines the reception state of the movement completion notification (Sig. 3) or the lens position deviation notification (Sig. 5) from the scanner control unit 25. In a state where the lens position deviation amount is within a predetermined range, a movement completion notification (Sig. 4) is constantly output from the scanner control unit 25 to the laser control unit 21, and the process proceeds to step S8 to emit light from the laser diode 31 described above. It is determined whether or not the light receiving processing operation has been performed a predetermined number of times. Then, the processes in steps S4 to S8 are repeated until the predetermined number of times is reached.

  If the processing operation has been performed a predetermined number of times in step S8, the process proceeds to step S9, and the reflected light reception timing from the laser emission start timing is determined based on the electrical signal detected in step S5. Is detected, and the distance from the target object 62 is calculated from the time difference result.

  In the laser control unit 21, after the processing operation up to step S9 described above is completed, the process proceeds to step S1, the subsequent processing operation is performed, and the scanner control unit 25 is instructed for the next projection angle position. . By moving the projection lens 37 in the horizontal and vertical directions and repeating the same operation, the beam angle is scanned in the horizontal and vertical directions.

  As described above, the projection lens 37 is repeatedly moved and stopped a predetermined number of times, then moved to the initial position of the beam scanning angle, and scanning is performed again.

  In the above-described embodiment, the time change, the movement amount, and the trajectory of the target lens position instruction at the time of the movement instruction are constant in each scan, but sequentially, according to the projection range at the time of movement, The time change, the movement amount, and the trajectory of the movement instruction may be changed.

  Next, a method of adjusting the projection beam optical axis in the present embodiment will be described with reference to FIGS.

  FIG. 6 is a diagram showing the relationship between the beam projection optical axis of the light projecting device and the distance detection between the target objects, and FIG. 7 is a flowchart for explaining the flow of optical axis adjustment and scanning width adjustment.

  As shown in FIG. 6A, the reflection plane 70 is installed at a position where the predetermined distance L is in front of the light projecting device 20. First, in step S41, the laser control unit 21 instructs the scanner control unit 25 so that the angle offset instruction is 0 degree. Next, in step S42, the laser control unit 21 issues an angle instruction to the scanner control unit 25 so that the beam projection direction is the scanning angle center, that is, the scanning origin direction. Then, in step S43, the lens position target is set according to the beam angle instruction by the scanner control unit 25, and the projection lens 37 is controlled by feedback control so that the detection position of the projection lens 37 matches the target position. The position is moved. After the projection lens 37 has been moved to the target position, a completion signal is reported to the laser controller 21.

  Thus, when the laser control unit 21 receives the movement completion signal from the scanner control unit 25, the pulsed light beam (L1) is output from the laser diode 31 in step S44, and the projection light is projected to the reflection plane 70 through the projection lens 37. 61 is projected. The reflected light (light beam) 63 reflected by the target object 62 is incident on the light receiving unit 27.

  Next, in step S <b> 45, the light beam incident on the light receiving unit 27 is detected by the light receiving sensor 56 through the light receiving lens 55. In step S46, the time difference td from when the laser diode 31 emits light until the reflected light 63 is detected is measured, and the distance L to the reflection plane 70 is detected.

When the projection optical axis is correctly adjusted, the time difference td from when the laser diode 31 emits light until the light receiving unit 27 detects the reflected light 63 is given by the following (inter-object distance L and luminous flux moving speed Vp) ( 1) Calculated by the equation.
td = 2L / Vp (1)
Therefore, the inter-object distance L is calculated by detecting the time difference td.

If the angle of the projection optical axis deviation is δ, the optical path length obtained by adding the projection light 61 and the reflected light 63 is 2 L / cos δ. Assuming that the time difference at this time is td ′, the time difference is extended to (1 / cos δ) times the above td. As a result, when the object distance is measured, it is detected (1 / cos δ) times the theoretical value. When the distance measurement result at this time is L ′, the following equation (2) is established.
tan ² δ = 1 + (L ′ / L) (2)
Accordingly, in step S47, the projection optical axis deviation amount δ is calculated from the deviation between the actual measurement value (distance measurement result) L ′ of the detection distance and the theoretical value L.

  Next, in order to detect the direction of the projection optical axis deviation amount δ, the following processing is performed. That is, in step S48, the scanning angle is instructed from the laser control unit 21 to the scanner control unit 25 so that the projection angle becomes θ1. Next, in step S49, the position of the projection lens 37 is moved in accordance with the projection angle instruction. In step S50, the laser diode 31 emits light, and a light beam is projected onto the reflection plane 70 as shown in FIG. 6B. In step S <b> 51, the light reflected from the reflection plane 70 is detected by the light receiving unit 27.

  In step S52, the time difference from when the laser diode 31 emits light until it is detected by the light receiving unit 27 is measured, and the distance is detected. The distance detected here is L1.

Here, when the distance between the objects is L and the light flux moving speed is vp, the detection time is expressed by the following equation (3).
td = 2L / (vp · cos θ1) (3)
The detection distance L1 is detected as L1 = L / cos θ1 from the detection time.

The relationship between the detection distance L1 and the projection direction θ1 is expressed by the following equation (4). Thereby, a projection direction is calculated in step S53.
cos θ1 = L / L1 (4)
When the angle instruction is θ1, the actually detected angle is θ1 ′.

  Similarly, θ1 has the same absolute value with respect to the center of the optical axis and is given an angle instruction θ2 in which the direction is opposite, the distance L2 is detected, and the actual projection angle θ2 ′ is detected from the detected distance. The These are performed by the processing operations of steps S54 to S59, but are the same as steps S48 to S53 described above except that θ2, θ2 ′, and L2 are replaced with θ1, θ1 ′, and L1, respectively. As a reference, the description is omitted here.

  In step S60, the actual projection angles θ1 ′ and θ2 ′ calculated by the above-described processing are compared. In step S61, the direction of the angle instruction with the larger absolute value of θ1 ′ and θ2 ′ is detected, and in the subsequent step S62, the direction of the optical axis deviation δ is calculated as an offset adjustment value instruction. The adjustment value (offset adjustment value) is held in the memory 53.

Next, in step S63, the ratio of the actual scanning amplitude to the scanning width instruction is calculated from the above θ1, θ2, θ1 ′, θ2 ′ according to the following equation (5).
Scanning amplitude deviation ratio k = (θ1′−θ2 ′) / (θ1−θ2) (5)
The scanner control unit 25 can perform adjustment so that the actual projection angle amplitude matches the scan indication angle amplitude by multiplying the target indication angle by a factor of 1 / k. In step S64, the scanning width ratio k calculated in this way is held in the memory 53 as a scanning head width adjustment value.

  Then, the projection direction of the projection light 61 is corrected based on the offset adjustment value and the scan deflection width adjustment value held in the memory 53, so that the projection direction of the laser diode 31 is always adjusted to a desired direction. Is possible.

  As described above, according to the present embodiment, in the state in which the projector is mounted without disassembling the projection optical axis, the swing width of the outgoing optical axis, the optical axis adjustment is easy, the temperature change of the actuator sensitivity characteristic, and the time It is possible to provide a light projecting device that can obtain high adjustment accuracy without being affected by adjustment deviation due to change.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  Further, the above-described embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the column of the effect of the invention Can be extracted as an invention.

  In addition, according to the said embodiment of this invention, the following structures can be obtained.

That is,
(1) a light source;
Means for controlling the amount of light emitted from the light source;
An optical element movable up and down, left and right;
Means for driving the optical element;
Position detecting means for detecting the position of the optical element;
Means for setting the amount of movement of the optical element;
Means for feedback controlling the position of the optical element from the detection result of the position detection means;
Means for adjusting and correcting the position of the optical element;
Storage means for moving position adjustment values;
A light projecting device comprising:

  (2) By setting an angle offset instruction value from the movement angle setting means, a value obtained by adding a movement amount corresponding to the angle offset amount to the movement amount setting value of the optical element is set, and scanning of the projection optical axis is performed. It is possible to adjust the scanning angle center of the projection angle by offsetting the angle center, and the amount of movement of the optical element with respect to the deviation of the scanning angle width due to the indication of the moving angle swing width and the deviation of the actual projection beam angle The projection device according to (1), wherein the projection beam angle range in the horizontal and vertical directions can be adjusted by correction, and the respective adjustment results are held.

  (3) As a means for detecting the position of the optical element corresponding to the projection optical axis, the position of the light spot transmitted from the light beam emitted from the first light source through the light guide element (slit) linked to the optical element is detected by the position detection element. The light projecting device according to (1) above, wherein the position of the optical element can always be detected by detecting.

  In the light projecting device of the above (1), the direction of the projection optical axis is changed depending on the movement position of the optical element, the movement amount is moved to a target position, and stop control is performed. Change the projection angle to an angle. By instructing the set amount of movement of the optical element position in the up / down / left / right directions at regular intervals and stopping at the target position instruction, by emitting a beam from the light source and detecting reflected light The projection light can be scanned at an arbitrary angle.

  In the above projector, the position of the optical element to be controlled and the target position indication value are shifted due to the output offset and detection sensitivity error of the position detection means. As a result, the projection angle instruction and the actual projection are actually projected. Although a deviation in the direction of the light beam may occur, it is possible to detect a projection angle instruction and a deviation in the actual projection direction, calculate a correction amount from the deviation amount, and hold the correction amount in the storage unit. Further, when controlling the position of the optical element, by referring to the correction amount from the storage means and correcting the control instruction value, the deviation between the projection angle instruction and the actual projection angle can be eliminated.

  In the above projector, the light beam generated from the light source enters the optical element and projects the transmitted light toward the target object as projection light. The optical element refracts incident light in accordance with the center position of the incident light and the amount of positional deviation between the center positions of the optical elements and projects it as reflected light. The projected light is projected in a direction shifted by the refraction angle with respect to the traveling direction of the incident light of the optical element. The refraction angle increases as the amount of positional deviation between the center position of incident light and the center position of the optical element increases. By moving the optical element in the vertical direction and the horizontal direction, the traveling direction of the projection light can be directed to the target direction in both the horizontal direction and the vertical direction.

  The movement position detection unit causes the light beam from the first light source to enter the light guide element that is linked to the optical element, detects the spot center position of the transmitted light by the position detection element, and obtains the movement amount of the optical element. The control means performs feedback control so as to move the optical element in the direction of correcting the deviation with respect to the deviation between the detected position and the target movement value. When the deviation from the target position falls within a predetermined range, the control means notifies the optical radar control unit of the completion of movement while operating to hold the optical element position. Upon receiving the above notification, the optical radar control unit detects the distance to the object by emitting the beam light toward the target object, detecting the reflected light from the object, and measuring the time difference from the projection to the light reception.

  Next, a method for adjusting the projection beam optical axis will be described.

  There are two causes of the optical axis deviation: an offset error that generates a quantitative deviation regardless of the angle, and an amplitude-dependent error that increases (decreases) substantially in proportion to the angle instruction value.

  The method for determining the offset error correction value is as follows. When an instruction is given to the projection beam control means so that the projection direction of the projection beam is the optical axis center, the amount of deviation between the actual projection beam projection direction and the optical axis center is measured. The offset of the optical element is adjusted so that there is no deviation. This offset adjustment value is recorded in the storage means as an offset error correction value.

  The method for determining the correction value for the amplitude-dependent error is as follows. The actual projection beam projection angle is detected when the angle at the beginning of the scanning range of the projection beam is given to the control means as the projection angle instruction. Similarly, the projection angle of the actual projection beam when the angle at the end of the scanning range of the projection beam is given to the control means as the projection angle instruction is detected. Thus, the angle width of the beam scanning range given to the control means and the actual projection beam projection angle width are detected from the beginning to the end of the scanning range of the projection beam. The swing width of the optical element is adjusted so that the angular widths match. This amplitude adjustment value is recorded in the storage means as an amplitude-dependent error correction value. By supplying the offset error correction value and the amplitude-dependent error correction value to the control unit and correcting the projection direction of the projection beam, the projection direction of the projection beam can always be adjusted to a desired direction.

1, showing an embodiment of the present invention, is a block configuration diagram showing an overall configuration of a laser radar to which a light projecting device of the present invention is applied. It is a figure explaining the relationship between the moving direction of the projection lens 37, and the direction of the projection light 61. FIG. It is a timing chart for demonstrating the projection lens movement control operation | movement of a laser radar and light source light emission control timing in one Embodiment of this invention. It is a flowchart for demonstrating the processing operation which the laser radar of one Embodiment of this invention scans a projection optical axis. 6 is a flowchart for explaining an operation of a subroutine “follow-up control” in step S12 in the flowchart of FIG. 4. It is the figure which showed the relationship between the beam projection optical axis of a light projector, and the distance detection of a target object. It is a flowchart for demonstrating the flow of optical axis adjustment and scanning width adjustment. It is the block diagram which showed the structure of the optical radar apparatus of a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 21 ... Laser control part, 23 ... Laser light-emitting device, 24 ... Scanner part, 25 ... Scanner control part, 27 ... Light-receiving part, 30 ... Lens holder, 31 ... Laser diode, 32, 33 ... Relay lens, 35 ... Wire spring, 36 ... support member, 37 ... projection lens, 38a, 38b ... driven member, 39a, 39b ... slit, 40 ... actuator, 41a, 41b ... light source, 43a, 43b ... position detector (PSD), 45 ... lens position indication calculation unit , 46 ... Position deviation detection unit, 47 ... Determination unit, 48 ... Control calculation unit, 50 ... Linear motor driver, 51 ... Position sensor calculation unit, 53 ... Memory, 61 ... Projected light, 62 ... Target object, 63 ... Reflected light .

Claims (7)

In an optical radar projector that detects an object by scanning a light beam emitted from a first light source and receiving reflected light from the object,
An optical element for setting a projection direction of a light beam emitted by the first light source;
A position detector for detecting the position of the optical element;
Conversion means for converting the projection direction of the light beam into the position of the optical element;
An actuator for moving the optical element;
Drive control means for controlling the drive of the actuator based on the target position of the optical element obtained by the conversion means and the detection position of the optical element detected by the position detector;
Adjustment value storage means for storing an adjustment value for correcting a deviation of the direction in which the light is projected by the light projecting device with respect to the specific target projection direction of the light;
Comprising
The light-projecting device, wherein the converting means corrects the projection direction with the correction value and converts it into the position of the optical element.   The light projecting device according to claim 1, wherein the specific target direction of the light beam is an angle corresponding to an origin and a maximum swing width.   2. The position detection means includes a second light source, a position detection element, and a slit that moves in conjunction with the optical element, and obtains a detection output of the optical element position. The light projector described. A first light source that emits a predetermined light beam;
A movable optical element for setting a projection direction of a light beam emitted from the first light source;
An actuator for two-dimensionally moving the optical element in a direction perpendicular to the optical axis direction of the first light source;
Position detecting means for detecting the position of the optical element;
Calculating means for calculating a target position to move the optical element based on the projection direction of the light beam;
The deviation of the projection direction of the light beam emitted from the first light source with respect to the specific target projection direction of the light beam is detected by the target position of the optical element calculated by the calculation means and the position detector. Drive control means for controlling the drive of the actuator to correct based on the detection position of the optical element;
A light projection device comprising: Adjustment value storage means for storing, as an adjustment value, a shift in the radiation direction of the light beam emitted from the first light source with respect to a specific target projection direction of the light beam;
The drive control means is based on the target position of the optical element calculated by the calculation means, the detection position of the optical element detected by the position detector, and the adjustment value stored in the adjustment value storage means. The projector according to claim 4, wherein driving of the actuator is controlled.   The light projection device according to claim 4, wherein the specific target projection direction of the light beam is an angle corresponding to an origin of scanning and a maximum swing width.   The position detection means includes a second light source that emits a light beam different from the first light source, a position detection element, a slit that moves in conjunction with the movement of the optical element, and radiation from the second light source. The light projecting device according to claim 4, further comprising: a position detection element that receives the received light beam through the slit and detects a position of the optical element.

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