DE102012207328A1 - System for acquisition of track profile for vehicle, has control device connected with light-time cameras and determining spacing and dimensions of uneven portion of track profile based on components of vehicle - Google Patents

Abstract

The system has light-time cameras (210, 220) i.e. PMD sensor, arranged at a front side of a vehicle and made to detect a lane of a wheel in a remote area. A control device (300) is connected with the light-time cameras, and determines spacing and dimensions of uneven portion (400) of a track profile (450) based on components i.e. control system (310) of the vehicle. The control device is engaged with the control system of an active suspension (320) under consideration of the recognized track profile and/or the recognized uneven portion. An independent claim is also included for a method for operating a system for acquisition of a track profile.

Description

The invention relates to a system and a method for detecting the road surface with a light time camera.

From the DE 100 50 569 A1 For example, a vehicle is known on the front side of which a measuring device for detecting a vertical lift of a section of a road at a predetermined distance is arranged. As a measuring device, for example, a video camera is proposed, which recognizes potholes or bumps on the basis of the color or gray shades of Fahrahnoberfläche. Alternatively, a laser system is proposed that uses a triangulation technique to determine the height of the measured surface section. Furthermore, it is provided to control the suspension system of the vehicle according to the acquired data. For example, spring rate, degree of damping, flow rate, pressure, vessel volume, height, etc. of the suspension system can be controlled to ensure smooth and stable ride.

From the DE 41 19 494 A1 A suspension control system is known in which an unspecified look-ahead sensor detects the road surface in front of a motor vehicle. The sensor is designed so that an output signal is generated according to the height of the detected bumps. Uneven road sections generate vibrations on the wheel, which are also transmitted to the motor vehicle via the suspension. In particular, large bumps cause strong and pulsed vibrations on the wheel and chassis. With a simple adaptive adjustment of the shock absorbers there is a risk that the damping is set too low, so that the shock absorbers tend to strike through. It is proposed to allow flexible, adaptive damping control only when the bumps are within predetermined thresholds.

The DE 10 2006 039 353 A1 discloses an apparatus and a method for influencing the spring force characteristic of an active chassis of a motor vehicle, in which two laser scanners for detecting a height profile ahead in the direction of travel of the motor vehicle are arranged in the front region of the motor vehicle. In this case, it is provided that the spring force characteristic of the wheel suspension can be adapted in advance to the course of the detected height profile. Furthermore, a control device is provided which calculates state variables on the basis of a comparison of temporally successively detected height profiles.

As depth image cameras, in particular, it is proposed to use time-of-flight cameras, with the time of flight camera not only comprising systems which determine distances directly from the light transit time, but in particular all the time of flight or 3D TOF camera systems which obtain transit time information from the phase shift of an emitted and received radiation , In particular, PMD cameras with photonic mixer detectors (PMD) are suitable as the light transit time or 3D TOF cameras, as described, inter alia, in the applications EP 1 777 747 . US Pat. No. 6,587,186 and also DE 197 04 496 described and, for example, by the company, ifm electronic gmbh 'as O3D camera relate. In particular, the PMD camera allows a flexible arrangement of the light source and the detector, which can be arranged both in a housing and separately.

The object of the invention is to improve a system for detecting a roadway profiling.

The object is achieved in an advantageous manner by the system according to the invention and a method for detecting a roadway profile by arranging at least one light cycle camera on a front side of a vehicle. A control device connected to the time of flight camera is further designed in such a way that, based on the data of the time of flight camera, a roadway profile and / or distances and dimensions of unevenness are determined and components of the vehicle are driven on this basis.

The use of a light runtime camera has the advantage that not only a dimension of an object or unevenness on the roadway can be detected, but at the same time a distance and by taking successive images and a speed of the object. It is thus possible to identify disturbing unevenness on the basis of information from the light-time camera alone without further sensors.

In further embodiments, it is provided to provide two or optionally also four light duration cameras in the front region of the vehicle, which each detect in pairs a lane of a wheel in a forward-looking manner. In the variant with four time of flight cameras, a first and second far-field time of flight camera in their assigned traffic lane detect a far-end area and a third and fourth near-field time of day camera capture a correspondingly assigned proximity area.

This procedure has the particular advantage that a prediction of possible driving disturbances can be made by the objects or unevennesses detected in the far field. The detection of the lane at close range immediately in front of the wheels allows the pre-calculated Unevenness is actually effective for the chassis.

Particularly advantageously, the control unit of the system is designed so that it can be intervened in the control system of an active suspension or an active chassis depending on the recognized roadway profile and / or the detected bumps. Advantageously, at least one property, for example the damping, of an active suspension is set by the control unit.

A pre-adjustment of the active suspension is particularly advantageously carried out by an unevenness detected in the far range, a final adjustment of the active suspension taking place as soon as the recognized unevenness is also detected in the near field.

The invention will be explained in more detail by means of embodiments with reference to the drawings.

Show it:

1 schematically the basic principle of photomix detection,

2 a vehicle with two light-time cameras in the front area of a vehicle,

3 a far-field detection of a bump,

4a . 4b FIG. 2 schematically shows an image of a roughness on a light transit time sensor and a corresponding signal course on the transit time sensor; FIG.

5 an embodiment with four light transit time cameras in the front region of a motor vehicle,

6 schematically a detection of bumps in a distance and close range,

7 an arrangement with two light time cameras and a common lighting.

In the following description of the preferred embodiments, like reference characters designate like or similar components.

1 shows a measurement situation for an optical distance measurement with a light time camera, as for example from the DE 197 04 496 is known.

The light transit time camera system 1 includes a transmitting unit or a lighting 10 . 100 with a light source 12 and associated beam shaping optics 15 as well as a receiving unit or light runtime camera 20 with a receiving optics 25 and a light time photo sensor 22 , The light time photo sensor 22 or light transit time sensor 22 has at least one pixel, but preferably a pixel array, and is designed in particular as a PMD sensor. The receiving optics 25 typically consists of improving the imaging characteristics of multiple optical elements. The beam shaping optics 15 the transmitting unit 10 is preferably formed as a reflector.

The measurement principle of this arrangement is essentially based on the fact that, based on the phase shift of the emitted and received light, the transit time and thus the distance covered by the received light can be determined. For this purpose, the light source 12 and the light time photo sensor 22 via a modulator 30 applied together with a certain modulation frequency M (p1) with a first phase position p1. The light source sends according to the modulation frequency 12 an amplitude modulated signal S (p1) with the first phase position p1. This signal or the electromagnetic radiation is in the illustrated case of an object 40 Reflected and due to the distance covered coincident with a second phase position p2 as a received signal S (p2) on the light transit time photo sensor 22 , In the time of flight sensor 22 the modulation signal M (p1) is mixed with the received signal S (p2), wherein the phase shift or the object distance d is determined from the resulting signal.

2 shows a front side of a motor vehicle, in which in each of the peripheral areas a first and second light time camera 210 . 220 are arranged. In the example shown, the time of day cameras are arranged below the vehicle headlights. The illumination of the first and second detection areas can be realized on the one hand via an integrated into the first and second light time camera lighting as well as a separate external lighting or possibly also be achieved by modulation of the illumination in the vehicle headlight. Likewise, the light runtime camera can also be accommodated in the installation space of the vehicle headlight. The detection areas E1, E2 are selected so that the expected lane of the vehicle is expected to lead through this monitored area.

3 shows a side view of this arrangement with a roadway 450 and a rub 400 in the detection range of at least one light time camera 210 . 220 , It is according to the invention provided that a control unit 300 based on the data of the time of day cameras 210 . 220 assessed the quality of road conditions and in a control system 310 an active suspension 320 intervenes. On the one hand, the roadway profile can be determined as such, for example, whether it is a smooth, rough or designed as cobblestone pavement, so as for example a basic setting of the chassis or the active suspension 320 make. On the other hand, the arrangement also allows detection of larger bumps 400 or possibly other disturbing objects on the roadway.

In the 3 shown rub 400 represents in their dimensions a significant impairment of the driving behavior and comfort behavior of the vehicle to which the arrangement according to the invention should react in a suitable manner by regulating the suspension. Through the light runtime camera 210 . 220 Both the distance and height and possibly volume of unevenness are determined. By taking several successive depth images, it is still possible, the dimension of the unevenness or of the object 400 and also to estimate the speed of the object in the direction of the vehicle and to determine a possible point of impact with a wheel or the vehicle. If the object exceeds a dangerous dimension, so that a collision of the vehicle with the object is to be feared, it is also provided according to the invention, for example, to alert the driver or, if necessary, intervene in safety functions of the vehicle. Otherwise, it is sufficient to make appropriate settings on the chassis or an active suspension without alarm. Based on the determined dimensions of the object or the unevenness 400 For example, the damping factors of the chassis can be adjusted so that occupants in the vehicle have to suffer little loss of comfort, and in any case should always be ensured that the wheels maintain sufficient contact with the ground and on the other hand, no overloading or puncture of the chassis is to be feared , As an additional measure, if necessary, the chassis can be adjusted in height, so that for particularly high bumps sufficient spring travel is available.

4a schematically shows an optical image of a bump 400 via a lens or a lens system 25 on the light transit time sensor 22 the light runtime camera 200 and 4b one of the optical image corresponding signal or distance profile at the light transit time sensor 22 , Over the surface of the light transit time sensor 22 Forms between the points u and v initially a flat roadway 450 from. In the distance diagram according to 4b the road level turns 450 as increasing distance d dar. The unevenness 400 , which spans between the points v and w, represents an interruption in the steadily increasing distance of the roadway profile. In the distance diagram, the distance d only increases insignificantly in the area of unevenness. At the height edge w of the unevenness 400 on the other hand, the road becomes the road again 450 behind the rub 400 and the distance jumps to a higher distance value d in order to rise steadily thereafter until the end of the detection range. bumps 400 can thus be recognized as a first approximation by means of discontinuities in the distance image.

5 shows a further variant in the front of the vehicle four Lichtlaufzeitkameras 210 . 220 . 230 . 240 are arranged. The first and second time of flight camera 210 . 220 detects each a long range in the extended lane of the vehicle and the third and fourth time of flight camera 230 . 240 each a short-range E3, E4 immediately in front of the wheels of the vehicle.

6 shows a side view of the arrangement according to 5 , In the case shown becomes in the long-range of a light time camera 210 . 220 a rub 400 detected. At a later date, this bumpiness has 400 the close range of the third or fourth light runtime camera 230 . 240 reached. For example, the dimensions, in particular the height and volume of the unevenness, can be determined anew by the second recognition in the near range, and the landing gear can be adapted further if necessary.

7 shows another embodiment with a global time of flight camera 200 which detects not only a lane area ahead, but a larger distance area. Further, a second time of flight camera 210 provided that detects a close range over the entire vehicle width. At least the lighting for the long-range is in a separate modulated lighting 100 If necessary, the lighting for the close range can also be used in the light-time camera 210 be integrated. As in the above examples, both the lane profile and unevenness in the long range can preferably be detected in ahead lane area, moreover, far-field detection also offers the possibility to detect vehicles or obstacles ahead. The close range of the first light runtime camera 210 is detected is divided into three areas in the illustrated area wherein a first and second area respectively detects the lane ahead of the vehicle and a third area detects a central area in front of the vehicle. The first and second areas are used to verify the unevenness, as shown in the examples above. The third area Primarily used to detect bumps or objects that pose a collision hazard.

In a further preferred embodiment, the system for detecting a roadway profile can also be integrated in a safety system of the vehicle. For example, about the global light-time camera 200 a far field and with the second or possibly further light time cameras 210 . 220 a near field in front of the vehicle to be monitored. Such a system is preferably designed such that an evaluation unit only triggers safety-relevant functions in the vehicle when a dangerous object is detected by the far-field light-time camera as well as subsequently in time by the near-field time of flight camera in a safety-relevant manner.

If necessary, the near field detection can be limited to a few light-propagation time pixels for faster data processing and / or output only distance information. For example, a possible collision time can be determined via the far-field light-time camera, wherein the near-field time of flight camera is only monitored as to whether the predicted collision object actually appears in the near field of the vehicle.

According to the invention, it is provided that a safety device of the motor vehicle is only released when the remote and the near field time of flight camera independently recognize a dangerous situation and output a safety signal.

8th shows an example of a possible linkage of the individual elements of the security system. The light runtime camera 200 is with a first evaluation unit 700 and the control sensor 210 with a second evaluation unit 710 connected.

The first evaluation unit 700 is preferably designed to detect objects in the monitored area E _F. For example, the size, position, speed and / or acceleration of the detected objects can be determined as data. If the trajectories of an object and of the vehicle have a collision intersection point, pre-warning signals with different weightings can be transmitted to the driver and / or subsequent safety systems. If, for example, a collision inevitably appears due to the distance and / or the speed, the evaluation unit sends 700 a trigger signal for subsequent safety devices 600 out. For example, as safety devices 600 automatic braking systems, airbags, belt tensioners and the like are activated, in particular to delay the vehicle and to reduce the consequences of a collision.

To avoid faulty activation of the safety devices 600 is the safety device 600 a triggering device 500 upstream. The triggering device 500 activates the safety device 600 preferably only if a second triggering signal at the triggering device 500 is applied.

This second triggering signal is transmitted via the at least one near field time of flight camera 210 . 220 . 230 and the subsequent second evaluation unit 710 made available. The second evaluation unit 710 preferably captures only object distances and derived quantities, such as an object speed. If a collision is to be expected on the basis of the recorded data, the second evaluation unit sends 710 a second trigger signal.

This procedure avoids false alarms with high safety, so that this system can also achieve high safety standards such as ASIL-D or SiA4.

9 shows a further embodiment in which both the first and the second evaluation unit 700 . 710 on the data of the far-field and near-field light-time camera 200 . 210 To fall back on. This allows, for example, that one evaluation unit can monitor the other evaluation unit, for example as a so-called watchdog.

For example, both evaluation units can also be designed such that each evaluation unit 700 . 710 the data of the far and near field time of flight camera 200 . 210 with respect to a collision and only outputs a trigger signal if both data make a collision unavoidable.

The evaluation units are preferably constructed with different hardware and / or use different programs or algorithms for evaluating the data.

By doing so, it is particularly advantageous to avoid random hardware and software errors.

Thus, a safety system for a vehicle with a far-field light-time camera is advantageous 200 having an array of receiving pixels and monitoring a surrounding area, with illumination for emitting a modulated light into the surrounding area to be monitored,
comprising a modulator for generating a modulation signal associated with the far-field time of flight camera and the illumination, and a first one Evaluation unit in which the data of the far-field light-time camera are evaluated and
when a detected danger situation, a first trigger signal is output, wherein the vehicle at least one near field time of flight camera is arranged, which preferably has a lower angular resolution than the far-field light-time camera and in particular detects at least a part of the environmental area to be monitored, and that a second evaluation is provided which evaluates data of the near-field time of flight camera and outputs a second triggering signal in the case of a dangerous situation detected by the second evaluation unit,
and that by a triggering device provided on the vehicle safety device is triggered only when both evaluation output a trigger signal.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10050569 A1 [0002]
• DE 4119494 A1 [0003]
• DE 102006039353 A1 [0004]
• EP 1777747 [0005]
• US 6587186 [0005]
• DE 19704496 [0005, 0023]

Claims (7)

A system for detecting a lane profile, in which at least one light runtime camera ( 200 . 210 . 220 . 230 . 240 ), with a control unit connected to the light-time camera ( 200 . 210 . 220 . 230 . 240 ) and a roadway profile ( 450 ) and / or distance and dimensions of bumps ( 400 ) and on this basis components ( 310 . 320 ) of the vehicle. System according to claim 1 with two light cycle cameras ( 210 . 220 ), each detecting a lane of a wheel ahead. System according to claim 1 with four light cycle cameras ( 210 . 220 . 230 . 240 A first and second far-field light-propagating time camera, each of which proactively detects a lane of a wheel in a distant area, and a third and fourth near-field time of flight camera (FIG. 230 . 240 ), which each proactively detect a lane of the wheel in a near field. System according to one of the preceding claims, in which the control unit ( 300 ) into a control system ( 310 ) of an active suspension ( 320 ) intervening in consideration of the recognized roadway profile and / or the detected bumps. Method for operating an aforementioned system for detecting a roadway profile, in which a roadway profile and the distance and dimensions of unevenness ( 400 ) and on this basis components ( 310 . 320 ) of the vehicle are controlled. Method according to Claim 5, in which, depending on a recognized roadway profile and / or depending on the distance and dimension of a unevenness ( 400 ), at least one characteristic of an active suspension ( 320 ) is set. Method according to one of the preceding method claims, in which, for each traffic lane, a long-range and a short-range area are provided with a time-of-flight camera ( 210 . 220 . 230 . 240 ) and in the case of a roughness ( 400 ) a presetting of the active suspension ( 320 ) and a final adjustment of the active suspension ( 320 ) takes place as soon as the detected unevenness ( 400 ) is detected in the near field.

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