JP4887849B2 - Vehicle obstacle detection device, road obstacle detection method, and vehicle with road obstacle detection device - Google Patents

Description

  The present invention relates to a vehicle road obstacle detection device for detecting an obstacle on a road surface, a road obstacle detection method, and a vehicle with a road obstacle detection device.

As this type of technology, the technology described in Patent Document 1 is disclosed. In this publication, the laser beam on the line is scanned from the laser radar provided on the vehicle body to the left and right in the same plane, and the obstacle is determined based on the distance between the detected obstacle and the laser radar, the depression angle of the laser light, and the scan angle. What measures the height from the road surface is disclosed.
JP 2005-128722 A

  When an obstacle is detected and the vehicle is controlled according to the height of the obstacle, the control processing time and the actuator operation time are required, so the laser gaze distance of the laser radar is determined as the control processing time and the actuator operation time. Must be set to a distance that takes into account That is, when the vehicle speed is low, the front center point distance is set close, and when the vehicle speed is high, the front gaze distance is set far. However, when the laser radar irradiates the road surface with a depression angle, the projection spot of the laser light irradiated on the road surface becomes larger in the irradiation direction as the forward gazing point distance becomes longer. For this reason, the error of the distance between the measured obstacle and the laser radar becomes large, and the height of the measured obstacle from the road surface may be increased.

  The present invention has been made paying attention to the above-mentioned problem, and the object is to measure the height of the obstacle from the road surface more accurately even when the distance of the forward gaze point of the laser radar is long. An object of the present invention is to provide a vehicle road obstacle detection device.

  In order to achieve the above object, in the vehicle road obstacle detection device, road road obstacle detection method, and vehicle with road road obstacle detection device of the present invention, the depression angle of the laser beam provided on the vehicle and irradiating the road surface with respect to the vehicle is changed. The laser radar that changes the distance of the front gazing point, which is the distance between the position where the laser beam is irradiated on the road surface and the vehicle body, and the distance between the laser radar and the obstacle from the reflected wave reflected by the obstacle Distance detecting means for detecting the obstacle, first height calculating means for calculating the height of the obstacle from the road surface from the distance between the laser radar and the obstacle and the depression angle of the laser light irradiated on the road surface with respect to the vehicle, and a laser The height from the road surface of the obstacle is calculated from the length detection means for detecting the shadow length of the obstacle irradiated with light, and the depression length of the obstacle and the depression angle of the laser light irradiated to the road surface with respect to the vehicle. 2nd high to Calculation means, in response to the forward fixation point distance, and the switching means switches to the first height calculation means and the second height calculation means, the provided.

  Therefore, in the occupant posture apparatus of the present invention, the height of the obstacle from the road surface can be measured more accurately even when the forward gazing distance of the laser radar is long.

  Hereinafter, the best mode for realizing a vehicle road obstacle detection device of the present invention will be described based on a first embodiment.

  First, the configuration will be described.

  FIG. 1 is an overall system diagram of a vehicle equipped with a vehicle road obstacle detection device of the present invention.

  The vehicle road obstacle detection device includes, as input devices, a laser radar 1 that irradiates a road surface with laser light, a wheel speed sensor 2 that detects a wheel speed, a steering angle sensor 3 that detects a steering angle of a steering wheel, An inertial navigation device 4 for detecting the vehicle body posture is provided. Also, a controller 5 for inputting and calculating information of these input devices, an angle actuator 6 for changing the laser beam irradiation angle of the laser radar 1 as an output device controlled by the controller 5, and a brake actuator for operating a brake 7 and a steering actuator 8 for steering the steered wheels.

  FIG. 2 is a diagram showing how the road surface shape is acquired by the laser radar 1. The laser radar 1 is provided in the upper part of the vehicle body 9, and irradiates a laser beam on the road surface ahead of the vehicle as shown in FIG. 2, scans the laser beam left and right, and receives a reflected wave from the road surface.

  The wheel speed sensor 2 obtains the vehicle speed from the wheel rotation speed on the driven wheel side.

  The steering angle sensor 3 detects the steering amount input by the driver.

  The inertial navigation device 4 includes an acceleration sensor and a gyro inside, and calculates the vehicle body posture by calculating the angular velocity of the vehicle body.

  The depression actuator 6 is an actuator that adjusts the laser beam irradiation angle of the laser radar 1, and adjusts the laser beam irradiation position on the road surface by adjusting the laser beam irradiation angle.

  The brake actuator 7 independently activates the braking force on each wheel of the vehicle regardless of the driver's brake operation.

  The steering actuator 8 steers the steered wheels of the vehicle regardless of the driver's steering.

  FIG. 3 is a control block diagram of the vehicle road obstacle detection device of the present invention.

  The vehicle body behavior calculation unit 5a inputs the wheel speed information from the wheel speed sensor 2, the steering angle information from the steering angle sensor 3, and the vehicle body posture information from the inertial navigation device 4, and calculates the vehicle body behavior. Here, the vehicle body behavior indicates the speed of the vehicle, the posture of the vehicle body with respect to the road surface, and the like.

  The forward gazing point distance calculation unit 5b receives the vehicle behavior information from the vehicle body behavior calculation unit 5a, and calculates a forward gazing point distance, which is a distance from the laser radar 1 to a position where the road surface is irradiated with laser light. The forward gazing distance is adjusted according to the vehicle speed. When the vehicle speed is slow, the forward gazing distance is set close, and when the vehicle speed is high, the forward gazing distance is set far.

  The depression actuator control unit 5c inputs the forward gazing point distance information calculated by the forward gazing point distance calculation unit 5b, and controls the depression angle actuator 6 so as to irradiate the laser beam on the road surface at the gazing point distance. This depression angle actuator control section 5c controls the depression angle actuator 6 so that the laser beam can irradiate the road surface at the forward gazing distance according to the vehicle speed, regardless of the posture of the vehicle body on acceleration / deceleration or uphill / downhill roads.

  The height calculation unit 5d includes a switching unit 5e, a first height calculation unit 5f, and a second height calculation unit 5g. Based on the reflected wave information of the laser beam received by the laser radar 1, a road surface height ( (Height with respect to the current vehicle contact position) is calculated.

  When the forward gazing point distance calculated by the forward gazing point distance calculation unit 5b is less than the set value, the switching unit (switching unit) 5d calculates the road surface height by the first height calculation unit 5f described later, When the gazing point distance is equal to or larger than the set value, the road surface height is calculated by a second height calculation unit 5f described later. The setting value of the forward gazing point distance is set by an error according to the forward gazing point distance of the first height calculation unit 5e and the second height calculation unit 5f, and will be described in detail later.

  The first height calculation unit 5e calculates the distance between the laser radar 1 and the region irradiated with the laser light from the laser light irradiated by the laser radar 1, and calculates the road surface height from this distance. The first height calculator 5e corresponds to the distance calculation means and the first height calculation means of the present invention.

  The second height calculator 5d acquires road surface height data from the laser light emitted by the radar radar 1, and calculates the road surface height from an area (shadows such as obstacles) where the road surface height data could not be acquired. To do. The second height calculator 5d corresponds to the length detection means and the second height calculation means of the present invention.

  The road shape / obstacle calculation unit 5h inputs the road surface height information calculated by the height calculation unit 5h, and calculates the road shape and the height and position of the obstacle.

  The route calculation unit 5i calculates a route suitable for vehicle travel based on information on the road shape and the height and position of the obstacle calculated by the road shape / obstacle calculation unit 5h.

  The braking / steering actuator control unit 5j outputs a control signal to the brake actuator 7 and the steering actuator 8 based on the road shape calculated by the route calculation unit 5i and the height and position information of the obstacle.

  Next, the operation will be described.

[Road obstacle detection processing]
FIG. 4 is a flowchart showing the flow of processing performed in the controller 5.

  In step S1, the vehicle body behavior calculation unit 5a calculates the vehicle body behavior from the wheel speed information, the steering angle information, and the vehicle posture information, and the process proceeds to step S2.

  In step S2, the front gaze distance calculation unit 5b calculates the front gaze distance at which the laser radar 1 irradiates laser light from the vehicle body behavior information calculated in step S1, and the process proceeds to step S3.

  In step S3, the control signal of the depression actuator 6 is calculated from the forward gaze distance information calculated in step S2, the calculated control signal is output to the depression actuator 6, and the process proceeds to step S4.

  In step S4, if the forward gaze distance calculated in step S2 is less than the set value in the switching unit 5e, the process proceeds to step S5, and if the forward gaze distance is greater than or equal to the set value, the process proceeds to step S6. To do. Since the forward gazing point distance is controlled to be variable according to the vehicle speed, it may be determined by setting a set value for the vehicle speed.

  In step S5, the first height calculator 5f obtains the distance between the laser radar 1 and the region irradiated with the laser light, calculates the road surface height from this distance, and proceeds to step S7.

  In step S6, the second height calculator 5g acquires road surface height data from the laser light emitted by the radar radar 1, and the road surface from an area (shadows such as obstacles) where the road surface height data could not be acquired. The height is calculated and the process proceeds to step S7.

  In step S7, the road shape / obstacle calculation unit 5h calculates the road shape and the height and position of the obstacle from the road surface height information calculated in step S5 or step S6, and the process proceeds to step S8.

  In step S8, the route calculation unit 5i calculates a route suitable for vehicle travel based on the road shape and obstacle height and position information calculated in step S7, and the process proceeds to step S9.

  In step S9, the brake / steering actuator controller 5j controls the brake actuator 7 and the steering actuator 8 based on the path information calculated in step S8.

[Road obstacle detection operation]
When the forward gazing point distance is less than the set value, the process proceeds in the order of step S1, step S2, step S3, step S4, step S5, step S7, step S8, step S9, and END.

  On the other hand, if the forward gaze distance is greater than or equal to the set value, the process proceeds in the order of step S1, step S2, step S3, step S4, step S6, step S7, step S8, step S9, and END.

  The on-road obstacle detection device for a vehicle according to the present embodiment is used in a system that controls a vehicle according to a road shape or an obstacle on a road surface. In order to control the vehicle, control processing time and actuator operation time are required. Therefore, in this embodiment, in step S2, the forward gazing point distance is calculated from the vehicle speed and the set time in consideration of the control processing time and the actuator operation time, and the forward gazing point is set in proportion to the vehicle speed. . For example, if the forward gazing distance is 20 [m] at 40 [km / h], the forward gazing distance is set to 40 [m] at 80 [km / h].

  Further, as the vehicle speed increases and the forward gazing point distance increases, the error in calculating the distance between the laser radar 1 and the region irradiated with the laser light increases. Therefore, in this embodiment, when the front gazing point distance is less than the set value, the distance between the laser radar 1 and the region irradiated with the laser light is obtained in step S5, and the road surface height is calculated from this distance. If the forward gazing point distance is greater than or equal to the set value, in step S6, the road surface height data is acquired from the laser light emitted by the radar radar 1 and the road surface height data cannot be acquired (obstacles). The road surface height is calculated from the shadows.

[Road obstacle detection]
(First height calculation)
Next, a method for obtaining the distance between the laser radar 1 and the region irradiated with the laser light and calculating the road surface height from this distance will be described. In this embodiment, measurement by this method is referred to as first height calculation.

  FIGS. 5A and 5B are diagrams for explaining the first height calculation. FIG. 5A shows a state seen from the side, and FIG. 5B shows a state seen from above.

  As shown in FIG. 5A, laser light 20 is emitted from the laser radar 1 provided at the height H above the vehicle body 9 with a depression angle η with respect to the road surface 11. At this time, the distance is N, and the laser beam is irradiated onto the road surface 11 (front gaze point 12) at a position away from the laser radar 1 by the front gaze point distance N. Further, as shown in FIG. 5B, the laser beam 20 is emitted from the laser radar 1 so as to scan the road surface 11 left and right. Therefore, the front gazing point 12 of the laser beam irradiated on the road surface draws an arcuate locus.

  For example, it is assumed that there is an obstacle 10 on the road surface in a direction shifted to the left by an angle θ with respect to the center axis in the front-rear direction of the vehicle. In this case, when the laser radar 1 scans the laser beam 20 in the scanning angle θ direction, the laser beam 20 is irradiated to the irradiation point 13 on the side surface of the obstacle 10 without being irradiated to the front gazing point 12 on the road surface.

  FIG. 6 is a schematic diagram for explaining a method for calculating the position of the irradiation point 13 where the obstacle 10 is irradiated with the laser beam. The x-axis indicates the vehicle longitudinal direction, the y-axis indicates the vehicle width direction, the z-axis indicates the vehicle vertical direction, and indicates the same direction as each axial direction shown in FIG.

From the time (time of flight) from when the laser radar 1 irradiates the laser beam 20 until the laser beam 20 is reflected at the irradiation point 13 of the obstacle 10 and received by the laser radar 1, A distance L between the laser radar 1 and the irradiation point 13 of the obstacle 10 is calculated. The distance from the laser radar 1 to the irradiation point 13 of the obstacle 10 when the time until the laser beam 20 is reflected at the irradiation point 13 of the obstacle 10 and the reflected wave is received by the laser radar 1 is t and the speed of light is c. L is represented by the following formula.
L = c · t (1)
The laser radar 1 is provided at a height H from the road surface. Therefore, the height Z from the road surface of the irradiation point 13 is obtained by the following equation.
Z = HL ・ cosθ ・ sinη

  If the depression angle η at which the laser radar 1 irradiates laser light is also constant, the irradiation point 13 of the obstacle 10 will rise as the vehicle travels. Therefore, the height of the uppermost part of the obstacle 10 can be measured by scanning the road surface with the laser beam while the vehicle is moving.

(Second height calculation)
Next, a method for obtaining road surface height data from the laser light emitted by the radar radar 1 and calculating the road surface height from an area where the road surface height data could not be obtained (shadows such as obstacles) will be described. In this embodiment, this method is referred to as a second height calculation.

  FIGS. 7A and 7B are diagrams for explaining the second height calculation. FIG. 7A shows a state viewed from the side, and FIG. 7B shows a state viewed from above. 7 also shows the position of the laser radar 1 from time ta to time tg and the forward gazing point 12 of the laser light 20 for each time in order to show the passage of time.

  At time ta and time tb, the laser beam 20 is not applied to the obstacle 10 and is applied to the road surface 11. On the other hand, since the laser beam 20 is irradiated on the obstacle 10 from the time tc to the time te, a part of the laser beam 20 irradiated from the time tc to the time te is not irradiated on the road surface 11. Further, at time tf and time tg after a lapse of time, the laser beam 20 passes over the obstacle 10 and irradiates the road surface 11, so that the obstacle 10 is not irradiated.

  Since the laser beam 20 irradiated on the obstacle 10 is reflected on the surface of the obstacle 10, an area where the road surface height information on the rear side cannot be obtained is formed on the obstacle 10. This region corresponds to the hatched portion in FIGS. 7A and 7B, and is called a shadow 14 in this embodiment. In this embodiment, the length Ls of the shadow 14 is obtained by data processing.

FIG. 8 is a schematic diagram illustrating a method for calculating the height Zh of the obstacle 10 from the road surface. Since the depression angle at which the laser radar 1 irradiates the laser beam 20 is an angle η, when the length of the shadow 14 is Ls, the height Zh of the obstacle is obtained by the following equation.
Zh = Ls ・ tanη

  By the way, in the calculation of the road surface height by the first height calculation and the second height calculation, an error may occur. Although there are various causes of errors, the following describes specific causes for the first height calculation and the second height calculation.

(Error in the first height calculation)
In the first height calculation, an error occurs when a shape in a different height direction is included in a region irradiated with the laser beam 20 of the laser radar 1 (hereinafter, this region is referred to as a spot 15). Since the spot 15 becomes larger as the depression angle η at which the laser radar 1 irradiates the laser light 20 becomes smaller, there is a high possibility that the spot 15 includes different height shapes. In other words, in the present embodiment, the depression angle η is reduced in order to set the front gazing distance farther as the vehicle speed increases, so the error in the height calculation by the first height calculation increases as the vehicle speed increases.

  Hereinafter, the error of the height calculation by the first height calculation will be described with reference to FIGS. 9 and 10.

  5 and 7, the laser beam 20 is irradiated in parallel to the optical axis 21 for easy illustration and explanation, and the obstacle 10 and the road surface 11 irradiated with the laser beam 20 are dotted. It was described as being. However, actually, the laser light 20 emitted from the laser radar 1 has a slight spread with respect to the optical axis 21. Therefore, the portions where the obstacle 10 and the road surface 11 are irradiated with the laser light 20 are planar. For this reason, the smaller the irradiation depression angle η of the laser light 20, the circular shape extending in the front-rear direction.

  Consider each reflected wave when the irradiation angle of the laser beam 20 is η1, η2 (η1> η2).

  FIG. 9 is a diagram when the road surface 11 is irradiated with the laser beam 20 from the laser radar 1. FIG. 9A shows the case where the irradiation depression angle of the laser beam 20 is η1, and FIG. 9B shows the case where the irradiation depression angle is η2. FIG. 9C shows an irradiation waveform 23 when the laser radar 1 irradiates the laser beam 20, and waveforms of reflected waves 24 and 25 from the road surface 11 in the case of irradiation depression angles η1 and η2. In FIG. 9C, the horizontal axis is taken as the time when the laser beam 20 is transmitted from the laser radar 1, but it is aligned with the reflection position in FIGS. 9A and 9B. For the purpose of description, the exact time relationship is not shown.

  The peaks of the reflected wave 24 and the reflected wave 25 in FIG. 9C exist on the time t1 axis and the time t2 axis. The time t1 and the time t2 are times necessary for the laser light 20 to reciprocate between the laser radar 1 and the forward gazing point 12, respectively. That is, when the spot 15 is irradiated only on the road surface 11 as shown in FIG. 9, the time position of the peak of the reflected wave is detected, and the above-described equation (1) is used to detect the laser radar 1 and the road surface 11. A distance from the forward gazing point 12 is calculated.

  When the spot 15 is irradiated only to the road surface 11, the shape of the spot 15 becomes a shape extended in the front-back direction, so that the irradiation depression angle (eta) of the laser beam 20 becomes small. By the way, the intensity of the irradiated laser beam 20 is the largest in the vicinity of the front gazing point 12 regardless of the irradiation depression angle η, and decreases as the distance from the front gazing point 12 increases. Therefore, when the spot 15 is irradiated only on the road surface 11, the peak of the reflected wave is the distance between the laser radar 1 and the front gazing point 12 regardless of the irradiation depression angle η of the laser light 20. It exists on the time required to make a round trip.

  That is, when irradiating the road surface 11 having the same shape in the height direction in the spot 15 (the obstacle 10 may be used if the shape in the height direction is the same), regardless of the irradiation depression angle η of the laser light 20. The time from when the laser radar 1 transmits the laser light 20 until it receives the reflected wave can be accurately obtained. Therefore, since the distance between the laser radar 1 and the road surface 11 (or the obstacle 10) can be accurately obtained, the height of the road surface 11 (or the obstacle 10) can be accurately obtained from this distance.

  FIG. 10 is a diagram when the obstacle 10 is irradiated with the laser beam 20 from the laser radar 1. 10A shows a case where the irradiation depression angle of the laser beam 20 is η1, and FIG. 10B shows a case where the irradiation depression angle is η2. FIG. 10C shows an irradiation waveform 23 when the laser radar 1 irradiates the laser beam 20, and waveforms of reflected waves 24 and 25 from the obstacle 10 in the case of the irradiation depression angles η1 and η2. In FIG. 10C, the horizontal axis is taken as the time when the laser beam 20 is transmitted from the laser radar 1, but it is aligned with the reflection position in FIGS. 10A and 10B. For the purpose of description, the exact time relationship is not shown.

  The peaks of the reflected wave 26 and the reflected wave 27 in FIG. 10C exist on the time t3 axis and the time t5 axis. Time t3 is a time required for the laser beam 20 to reciprocate the distance between the laser radar 1 and the irradiation point 13. However, the time t5 is shorter than the time t4 required for the laser beam 20 to reciprocate the distance between the laser radar 1 and the irradiation point 13. That is, in the case of FIG. 10A, the position of the reflected wave peak at time t3 is detected, and the distance between the laser radar 1 and the irradiation point 13 on the obstacle 10 is determined by using the above-described equation (1). Calculated. On the other hand, in the case of FIG. 10B, the position of the reflected wave peak at time t5 is detected, and the distance between the laser radar 1 and the irradiation point 13 on the obstacle 10 using the above-described equation (1). Is not calculated.

  The above reason will be described separately for the case shown in FIG. 10A and the case shown in FIG.

  As shown in FIG. 10A, when the irradiation angle η of the laser beam 20 is large and the spot 15 is small with respect to the obstacle 10, the laser beam 20 is irradiated only on the side surface of the obstacle 10. In this case, although the spot 15 irradiates a shape in a different height direction, the intensity of the laser beam 20 irradiated on the side surface of the obstacle 10 is the highest near the irradiation point 13 and decreases as the distance from the irradiation point 13 increases. Therefore, the intensity of the reflected wave from the irradiation point 13 is the highest.

  Therefore, the peak of the reflected wave 26 exists on the time t3 axis necessary for the laser beam 20 to reciprocate the distance between the laser radar 1 and the irradiation point 13.

  On the other hand, as shown in FIG. 10B, when the irradiation depression angle η of the laser beam 20 is small and the spot 15 is large with respect to the obstacle 10, the laser beam 20 is applied to the side surface of the obstacle 10 and the road surface 11. Will be irradiated. Since the side surface of the obstacle 10 stands at an angle with respect to the road surface 11, the spot 15 on the side surface of the obstacle 10 is the same as the case where the road surface 11 is irradiated with the irradiation depression angle η 2 from the irradiation depression angle η 2 of the laser beam 20. It becomes such a shape. That is, the spot 15 on the side surface of the obstacle 10 has a smaller area than the spot 15 on the road surface 11.

  The reflected wave 27 can be decomposed into a reflected wave 27a from the obstacle 10 and a reflected wave 27b from the road surface 11, as indicated by a dotted line in FIG. Since the spot 15 on the side surface of the obstacle 10 has a smaller area than the spot 15 on the road surface 11, the reflected wave 27 is affected by the reflected wave 27 b from the road surface 11, and the laser radar 1 and the irradiation point 13 are affected. There is a peak on the time t5 axis, which is a time before the time t4 required for the laser beam 20 to reciprocate the distance.

From the above, as the front gazing point distance is set farther as the vehicle speed increases, the spot 15 becomes a shape extending in the front-rear direction and the area increases. Therefore, the error in the road surface height calculation by the first height calculation is growing.
(Error in second height calculation)

  The resolution of the height calculation by the second height calculation is determined by the height scanning interval D that is the height interval of the adjacent laser beams 20. For example, if the height calculation result when the height scanning interval D is 1 [cm] is 10 [cm], the actual height is between 9 [cm] and 11 [cm]. become. That is, the error is ± 1 [cm].

  The height scanning interval D is generated by the scanning interval G of the laser beam 20 in the vehicle traveling direction and the irradiation depression angle η.

  First, the generation of an error due to the scanning interval of the laser beam 20 will be described with reference to FIG.

  11 (a) and 11 (b), the irradiation depression angle η of the laser beam 20 is the same, but the vehicle speed is different, for example, 40 [km / h] in FIG. 11 (a), and in FIG. 11 (b). 80 [km / h]. If the scan rate (time from scanning to the next scanning) is constant and the scanning interval of the laser beam 20 is G when it is 40 [km / h], if it is 80 [km / h] 2G.

Further, the height scanning interval D between the laser beams 20 is expressed by the following equation, where D1 is 40 [km / h] and D2 is 80 [km / h].
D1 = G ・ tanη
D2 = 2G ・ tanη
However, 0 <η ≦ 90 °
Therefore, D1 <D2.

  Therefore, it can be seen that if the irradiation angle η of the laser beam 20 is constant, the error increases as the vehicle speed increases.

  Next, generation of errors due to depression angles will be described with reference to FIG.

  12 (a) and 12 (b), the vehicle speed is equal to 40 [km / h] and the scanning interval of the laser beam 20 is also equal to G, but the irradiation angle η of the laser beam 20 is different, and FIG. The irradiation depression angle η1 of the laser beam 20 in a) is set to be larger than the irradiation depression angle η2 in FIG.

Further, the height scanning interval D between the laser beams 20 is expressed by the following equation, where D3 is the irradiation depression angle η1 of the laser beam 20 and D4 is the irradiation depression angle η2.
D3 = G ・ tanη1
D4 = G ・ tanη2
However, 0 <η2 <η1 ≦ 90 °
Therefore, D3> D4.

  That is, it can be seen that the error increases as the irradiation depression angle η of the laser light 20 increases.

  By the way, in this embodiment, when the vehicle speed is low, the front center point distance is set close, and when the vehicle speed is high, the front gazing point distance is set far. That is, in this embodiment, the scanning interval G of the laser beam 20 in the vehicle traveling direction and the irradiation depression angle η are changed according to the vehicle speed.

  Next, generation of errors due to the scanning interval G of the laser beam 20 in the vehicle traveling direction and the irradiation depression angle η will be described with reference to FIG.

  In FIG. 13A, the vehicle speed is 40 [km / h], the scanning interval of the laser light 20 is G, and the irradiation depression angle is η1. In FIG. 13B, the vehicle speed is 80 [km / h], the scanning interval of the laser beam 20 is 2 G, and the irradiation depression angle is η2.

At this time, the height scanning interval D of the laser beam 20 is expressed by the following equation when D3 is when the vehicle speed is 40 [km / h] and D4 when the vehicle speed is 80 [km / h].
D5 = G ・ tanη1
D6 = 2G ・ tanη2
However, 0 <η2 <η1 ≦ 90 °

  By the way, the forward gazing distance when the vehicle speed is 80 [km / h] is twice that when it is 40 [km / h], so that 2 · tanη1 = tanη2. Therefore, D5 = D6.

  That is, when the scanning interval of the laser beam 20 and the irradiation depression angle η of the laser beam 20 are changed according to the vehicle speed as in this embodiment, the error is constant.

(Switching the calculation method according to the forward gaze distance)
In the first height calculation, the error increases as the forward gazing point distance increases, that is, as the vehicle speed increases. On the other hand, in the second height calculation, an error occurs constantly regardless of the forward gaze distance. FIG. 14 shows the result of measuring the magnitude of the error by the first height calculation and the second height calculation according to the forward gaze distance by simulation.

  If the forward gaze distance is short, the error in the first height calculation is smaller than the error in the second height calculation. As the forward gazing point distance increases, the error in the first height calculation increases, but the error in the second height calculation becomes constant. Therefore, when the forward gazing point distance is N1, the error in the first height calculation is larger than the error in the second height calculation.

  Therefore, in the present embodiment, the switching unit 5e of the controller 5 causes the road surface height to be calculated by the first height calculation when the forward gazing distance is less than N1, as shown in FIG. When the distance is N1 or more, the road surface height is calculated by the second height calculation.

  FIG. 16 is a diagram illustrating processing performed in each device in the present embodiment. 16A shows the relationship between time and vehicle speed, FIG. 16B shows the relationship between vehicle speed and front gazing distance, FIG. 16C shows the relationship between the irradiation depression angle of the laser light 20 and the front gazing distance, and FIG. (D) shows the relationship between the forward gaze distance and the calculation result of the road surface height by the first height calculation and the second height calculation.

  As the vehicle speed increases as shown in FIG. 16 (a), the forward gazing distance is set farther as shown in FIG. 16 (b), and the forward gazing distance as shown in FIG. 16 (c). Is set farther away, the irradiation depression angle of the laser light 20 is reduced.

  The thin solid line in FIG. 16 (d) indicates the road height calculation result by the first height calculation, the dotted line indicates the road height calculation by the second height calculation, the alternate long and short dash line indicates the true height value, A thick line indicates an output value of a calculation result obtained by switching the first height calculation and the second height calculation by the switching unit 5e. The calculation results of the first height calculation and the second height calculation indicate the upper and lower limits of the error range.

  As shown in FIG. 16D, since the first height calculation and the second height calculation are switched according to the forward gazing distance, the calculation error of the road surface height can be reduced.

  Next, the effect of the present embodiment will be described.

  A laser radar 1 provided on the vehicle, which changes the depression angle of the laser beam applied to the road surface with respect to the vehicle so that the front gaze distance, which is the distance between the position where the laser beam is applied to the road surface and the vehicle body, is variable; Detecting means for detecting the distance between the laser radar and the obstacle from the reflected wave of the reflected laser light reflected by the obstacle, and the distance between the laser radar and the obstacle, and the depression angle of the laser light irradiated on the road surface with respect to the vehicle The first height calculator 5f as a first height calculator for calculating the height of the obstacle from the road surface, and length detection for detecting the shadow length of the obstacle irradiated with the laser beam And second height calculating means as second height calculating means for calculating the height of the obstacle from the road surface from the shadow length of the obstacle and the depression angle of the laser light applied to the road surface with respect to the vehicle And depending on the distance of the forward gazing point, Provided switching portion 5e of the switching means switching the high computation object into a first height calculation unit 5f and the second height calculation unit 5g.

  Therefore, the first height calculation unit 5f or the second height calculation unit 5g is switched according to the forward gazing point distance, and the obstacle height calculation of the first height calculation unit 5f or the second height calculation unit 5g is performed. It is possible to calculate the obstacle height with a smaller error. Therefore, the height calculation can be performed more accurately.

  The switching unit 5e has a long forward gazing distance, and an obstacle height error calculated by the first height calculation unit 5f is calculated by the second height calculation unit 5g. The obstacle height calculation is switched from the first height calculation unit 5f to the second height calculation unit 5g at the forward gazing distance that is larger than the height error from the first point.

  Therefore, regardless of the forward gazing distance, the height of the obstacle is determined by a method with a small height error calculated from the height of the obstacle in the first height calculator 5f and the second height calculator 5g. It becomes possible to calculate. Therefore, the height calculation can be performed more accurately.

  The second height calculation unit 5g calculates the height of the obstacle by multiplying the length of the shadow of the obstacle by the cosine of the depression angle of the laser light applied to the road surface with respect to the vehicle.

  Therefore, it is possible to calculate the height of the obstacle by processing the reflected wave data acquired by the laser radar 1. Therefore, an obstacle height calculation error can be obtained even when the forward gaze distance is long, without adding a new device to the device necessary for calculating the height of the obstacle by the first height calculator 5f. Can be reduced.

  In the laser radar 1, the depression angle of the laser beam 20 is made variable by the depression actuator 6, so that the forward gazing distance is increased in proportion to the vehicle speed.

  Therefore, regardless of the vehicle speed, the depression angle can be controlled so that the arrival time until the vehicle reaches the front gazing point is longer than the control processing time and the actuator operation time. Therefore, even when there is an obstacle to be avoided by the vehicle at the position of the forward gazing point distance, the actuator can be reliably operated and the obstacle can be avoided.

  A first height that calculates the height of the obstacle from the road surface from the distance between the laser radar 1 and the obstacle according to the front gazing distance, which is the distance between the position where the laser light 20 is applied to the road surface and the vehicle body. The means for performing the height calculation and the means for performing the second height calculation for calculating from the length of the shadow of the obstacle irradiated with the laser light are switched.

  Therefore, the first height calculation or the second height calculation is switched according to the forward gaze distance, and the obstacle height is determined by the smaller of the obstacle height calculation errors in the first height calculation or the second height calculation. Can be calculated. Therefore, the height calculation can be performed more accurately.

  A procedure for changing the angle of depression of the laser beam irradiated to the road surface from the laser radar 1 with respect to the vehicle so that the front gaze distance, which is the distance between the position where the laser beam is irradiated on the road surface and the vehicle body, is variable, and the front gaze distance Accordingly, as a means for calculating the height of the obstacle from the road surface, a first height calculation calculated from the distance between the laser radar 1 and the obstacle and the depression angle of the laser beam 20 irradiated on the road surface with respect to the vehicle is performed. A procedure for selecting a means to perform, a means for performing a second height calculation based on the length of the shadow of the obstacle and the depression angle of the laser beam 20 irradiated on the road surface with respect to the vehicle, and the obstacle by the selected means The obstacle on the road was detected from the procedure to calculate the height from the road surface.

  Therefore, the first height calculation or the second height calculation is switched according to the forward gaze distance, and the obstacle height is determined by the smaller of the obstacle height calculation errors in the first height calculation or the second height calculation. Can be calculated. Therefore, the height calculation can be performed more accurately.

  ・ Laser radar that changes the forward gaze distance, which is the distance between the position where the laser beam is irradiated on the road surface and the vehicle body, by changing the depression angle of the laser beam irradiated on the road surface with respect to the vehicle on the vehicle with the obstacle detection device on the road 1 and distance detecting means for detecting the distance between the laser radar and the obstacle from the reflected wave reflected by the obstacle on the irradiated laser beam, and the distance between the laser radar and the obstacle, and the laser beam applied to the road surface From the depression angle with respect to the vehicle, a first height calculation unit 5f as a first height calculation means for calculating the height of the obstacle from the road surface, and the length of the shadow of the obstacle irradiated with the laser light are detected. A second height calculating means for calculating the height of the obstacle from the road surface from the length of the obstacle detecting means, and the shadow length of the obstacle and the depression angle of the laser light applied to the road surface with respect to the vehicle. Height calculation means and forward gaze distance Depending on, providing the switching portion 5e of the switching means switching the height calculation obstacle into a first height calculation unit 5f and the second height calculation unit 5g.

  Therefore, the first height calculation unit 5f or the second height calculation unit 5g is switched according to the forward gazing point distance, and the obstacle height calculation of the first height calculation unit 5f or the second height calculation unit 5g is performed. It is possible to calculate the obstacle height with a smaller error. Therefore, the height calculation can be performed more accurately.

(Other examples)
The best mode for carrying out the present invention has been described based on the first embodiment. However, the specific configuration of the present invention is not limited to the first embodiment and does not depart from the gist of the present invention. Any change in the design of the range is included in the present invention.

1 is an overall system diagram of a vehicle on which a vehicle road obstacle detection device according to a first embodiment is mounted. It is a figure which shows a mode that the shape of the road surface is acquired by the laser radar based on Example 1. FIG. 1 is a control block diagram of a vehicle road obstacle detection device according to Embodiment 1. FIG. 3 is a flowchart illustrating a flow of processing performed in the controller according to the first embodiment. It is a figure explaining the 1st height calculation based on Example 1. FIG. It is a schematic diagram explaining the method which calculates the position of the irradiation point which irradiated the laser beam to the obstacle based on Example 1. FIG. It is a figure explaining the 2nd height calculation based on Example 1. FIG. It is a schematic diagram explaining the method to calculate height Zh from the road surface of an obstruction based on Example 1. FIG. It is a figure when the road surface is irradiated with the laser beam from the laser radar according to the first embodiment. It is a figure when the laser beam 20 is irradiated to the obstacle 10 from the laser radar 1 according to the first embodiment. It is a figure explaining generation | occurrence | production of the error by the scanning interval of a laser beam based on Example 1. FIG. It is a figure explaining the generation | occurrence | production of the error by the irradiation depression angle of the laser beam based on Example 1. FIG. It is a figure explaining the generation | occurrence | production of the error by the scanning interval and irradiation depression angle of the laser beam based on Example 1. FIG. It is a graph which shows the result of having measured the magnitude | size of the error by the 1st height calculation according to Example 1, and the 2nd height calculation according to the front gaze distance. It is a figure explaining switching in the switching part which concerns on Example 1 between the 1st height calculation and the 2nd height calculation. It is a figure which shows the process performed in each apparatus based on Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser radar 2 Wheel speed sensor 5 Controller 5a Vehicle behavior calculating part 5b Forward gaze distance calculating part 5d Height calculating part 5e Switching part 5f 1st height calculating part 5g 2nd height calculating part

Claims (7)

A laser radar which is provided in a vehicle and changes a depression angle of the laser beam applied to the vehicle with respect to the vehicle so as to vary a front gazing distance which is a distance between a position where the laser beam is applied to the vehicle and a vehicle body;
Distance detecting means for detecting the distance between the laser radar and the obstacle from the reflected wave of the irradiated laser beam reflected by the obstacle;
First height calculation means for calculating the height of the obstacle from the road surface from the distance between the laser radar and the obstacle and the depression angle of the laser light applied to the road surface with respect to the vehicle;
A length detecting means for detecting the length of the shadow of the obstacle irradiated with the laser beam;
Second height calculating means for calculating the height of the obstacle from the road surface from the length of the shadow of the obstacle and the depression angle of the laser light applied to the road surface with respect to the vehicle;
Switching means for switching between the first height calculating means and the second height calculating means according to a forward gaze distance;
An on-road obstacle detection device for a vehicle characterized by comprising: The vehicle road obstacle detection device according to claim 1,
The switching means has the obstacle in which the distance from the road surface of the obstacle calculated by the first height calculating means is calculated by the second height calculating means because the distance from the forward gazing point becomes long. A vehicle road obstacle characterized in that the vehicle is a means for switching between the first height calculating means and the second height calculating means at a forward gazing distance that is larger than an error in height from the road surface. Detection device. In the vehicle road obstacle detection device according to claim 1 or 2,
The second height calculating means is a means for calculating by multiplying the shadow length of the obstacle by the cosine of the depression angle of the laser beam applied to the road surface with respect to the vehicle. Object detection device. The vehicle road obstacle detection device according to any one of claims 1 to 3,
The on-road obstacle detection device for a vehicle, wherein the laser radar increases the distance of the forward gazing point in proportion to a vehicle speed. A means for calculating the height of the obstacle from the road surface from the distance between the laser radar and the obstacle and the laser light are applied according to the distance from the front gazing point, which is the distance between the position where the laser light is applied to the road surface and the vehicle body. A vehicle road obstacle detection device for switching between means for calculating from the length of the shadow of the obstacle. A procedure for changing the forward gazing distance, which is the distance between the position of the laser beam irradiated on the road surface and the vehicle body, by changing the depression angle of the laser beam irradiated on the road surface from the laser radar;
Means for calculating the height of the obstacle from the road surface in accordance with the forward gazing distance, and calculating from the distance between the laser radar and the obstacle and the depression angle of the laser light applied to the road surface with respect to the vehicle; A procedure for selecting a means for calculating from the shadow length of the obstacle and the depression angle of the laser light applied to the road surface with respect to the vehicle;
A road obstacle detection method comprising: calculating a height of the obstacle from the road surface by selected means. A laser radar that varies a forward gazing distance that is a distance between a vehicle body and a position where the laser beam irradiated to the road surface changes a depression angle with respect to the vehicle to irradiate the laser beam to the road surface;
Distance detecting means for detecting the distance between the laser radar and the obstacle from the reflected wave of the irradiated laser beam reflected by the obstacle;
First height calculation means for calculating the height of the obstacle from the road surface from the distance between the laser radar and the obstacle and the depression angle of the laser light applied to the road surface with respect to the vehicle;
A length detecting means for detecting the length of the shadow of the obstacle irradiated with the laser beam;
Second height calculating means for calculating the height of the obstacle from the road surface from the shadow length of the obstacle and the depression angle of the laser light applied to the road surface with respect to the vehicle;
Switching means for switching between the first height calculation means and the second height calculation means in accordance with the forward gaze distance;
A vehicle with a road obstacle detection device.

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