DE102018212251B4 - Method for tracking the adjustment of a radar sensor in a motor vehicle and motor vehicle - Google Patents

Abstract

Method for tracking the adjustment of a radar sensor (2, 3) in a motor vehicle (1), at least one position sensor (7) coupled to the radar sensor (2, 3) being used to determine a current position of the radar sensor (2, 3), by evaluating sensor data of the position sensor (7) to determine a deviation from a target installation position of the radar sensor (2, 3) and adjusting the adjustment based on this deviation, the radar sensor (2, 3) being provided with a mechanical, controllable adjusting device (8 ) of the motor vehicle (1), characterized in that when a first deviation criterion describing a lower deviation is met, only electronic adjustment of the adjustment by adapting the control of the radar sensor (2, 3) and / or evaluating radar data (15) the radar sensor (2, 3) is carried out and the ver Adjusting device (8) for mechanical adjustment of the adjustment is controlled, wherein if a mechanical limitation for the mechanical adjustment of the adjustment is reached, a further deviation is at least partially compensated for by electronic adjustment of the adjustment.

Description

The invention relates to a method for tracking the adjustment of a radar sensor in a motor vehicle, wherein at least one position sensor that is motion-coupled to the radar sensor is used to determine a current position of the radar sensor by evaluating sensor data of the position sensor to determine a deviation from a desired installation position of the radar sensor and the adjustment is carried out on the basis of this deviation, with the radar sensor being assigned a mechanical, controllable adjusting device of the motor vehicle. In addition, the invention relates to a motor vehicle.

Radar sensors are now standard equipment in motor vehicles and are mainly used to detect the surroundings of the motor vehicle. Radar data from the radar sensors can be used by various vehicle systems, in particular for functions of driver assistance systems such as parking aids, blind spot monitoring, pre-crash sensing and stop-and-go functions. Radar sensors have the advantage of also being concealed within the motor vehicle, for example in bumpers of the motor vehicle behind a plastic cover of the bumper and / or behind an external radome and / or an external emblem. So that the radar sensors have their intended detection range, they are installed in certain installation positions in certain installation positions. Measured radar data, in particular measured angles, relate accordingly to this predetermined target installation position. Radar sensors can, for example, be attached to a bumper and / or to a body part.

For example, the radar sensor can have a high-frequency and a low-frequency part. The high-frequency part generates high-frequency radar signals in the range of approx. 10 - 80 gigahertz. The radar signals are sent and received via antennas of an antenna arrangement of the radar sensor. The high-frequency received radar signals are converted and mixed down to a low frequency. The low-frequency radar signals are processed in the low-frequency section.

After the radar sensor has been installed in its installation position or installation position, the radar sensor is usually adjusted in this regard, so that evaluated radar data can be obtained in relation to a vehicle coordinate system, in particular with regard to the angles contained in the radar data at which an object is measured. Changes in the installation position, which can occur on the one hand due to signs of aging, e.g. material fatigue, and / or various types of damage to the motor vehicle, e.g. minor collisions, but also temporary effects, e.g. strong headwinds on a bumper, can lead to measured angles in particular are no longer sufficiently accurate in the radar data. This applies in particular to long-range radar sensors that can be installed, for example, in the front area of the motor vehicle. Especially in the case of objects detected at large distances, there may be significant deviations in the measured angles when the installation position of the radar sensor changes, so that the performance of the radar sensor is impaired. An angle measurement with the radar sensor would be incorrect since the installation position of the radar sensor has changed relative to the vehicle coordinate origin. Various approaches have already been proposed to counteract such misalignment effects.

It is already known in the prior art to use the radar data recorded by the radar sensors themselves in order to detect a misalignment of the radar sensor and to carry out an electronic adjustment of the adjustment, that is to say a recalibration. This misalignment detection, however, requires a relative movement of the motor vehicle to the environment, which must also have certain objects of a given structure. Suitable environmental objects for misalignment detection are, for example, crash barriers and / or other extensive environmental objects. The duration of such a readjustment process depends on many factors that can hardly be influenced within the motor vehicle, in particular on the nature of the surrounding objects (guardrail, tunnel, trees, peripheral buildings and the like). Other influencing factors are movement data of one's own motor vehicle, in particular speed, steering angle and the like. If the conditions for a detection of a misalignment and a corresponding adjustment of the adjustment are not optimal, this process, which can also be referred to as autocalibration, can take a very long time, for example a few minutes to hours. For automated driving functions and / or safety-relevant functions of vehicle systems, however, it is essential to maximize the availability of the radar sensors. Long-term auto calibration or detection of misalignment is not optimal for this.

In another approach it strikes DE 199 34 197 A1 an automatic adjustment device for a sensor attached to a vehicle, in particular for a radar sensor. A measuring device and an adjusting device are assigned to the sensor, wherein the measuring device detects and realizes the actual orientation of the sensor a deviation from a predetermined target orientation of the sensor outputs a control signal to the adjusting device, whereby the sensor is adjusted in the target orientation, the sensor being pivotable in relation to a horizontal plane and in relation to a vertical plane. The measuring device comprises a position sensor for detecting the orientation of the position-dependent sensor, the position sensor being rigidly connected to the position-dependent sensor.

Such designs also have several disadvantages. On the one hand, the wear of the adjusting device is significantly increased through frequent use. On the other hand, the in DE 199 34 197 A1 Given the self-contained procedure, neither the radar sensor itself nor other vehicle systems are aware that the adjustment has been made or to what extent this has been done, which can lead to problems in particular if complete mechanical tracking to restore the desired installation position is no longer possible is.

DE 10 2015 005 570 A1 relates to a method for adjusting and / or calibrating an environmental sensor. It is proposed to use an inertial sensor coupled to a sensor element in order to determine an actual orientation of the sensor element and to adjust and / or calibrate the environmental sensor to a target orientation, depending on a deviation of the actual orientation from the Target alignment. This involves the basic calibration immediately after installation, for which reference objects or reference patterns (so-called targets) have been used so far, which are now to be dispensed with. Essentially two alternative options with equal rights are named, namely adjustment and / or calibration. Adjustment can include issuing adjustment instructions as well as using a robot.

DE 10 2016 207 213 A1 discloses a radar system, specifically a mobile radar system for a vehicle, in which a transceiver arrangement defines a transceiver area. A position sensor unit is arranged in a stationary and rotationally fixed manner with respect to the transceiver area and provides one or more signals representative of the position, the position and / or the orientation of the transceiver area of the transceiver arrangement. In this way, a misalignment can be automatically recognized, evaluated and corrected. The automatic correction can be effected by adapting the transmission characteristic and / or the reception characteristic, but also by using an alignment unit for aligning the transceiver area.

GB 2 396 500 B relates to a method of correcting radar misalignment. There, sensor data of the radar sensor itself are to be used to determine a misalignment angle of the radar beam, this misalignment angle then being able to be compared with a threshold value, it being only determined when this threshold value is exceeded that the radar sensor requires physical adjustment of the adjustment. If this is the case, a corresponding message is output so that manual adjustments can be made in a workshop.

The invention is therefore based on the object of allowing an improved tracking of an adjustment of a radar sensor.

To achieve this object, a method of the type mentioned at the outset provides that, when a first deviation criterion describing a lower deviation is met, only an electronic adjustment of the adjustment is carried out by adapting the control of the radar sensor and / or evaluating radar data of the radar sensor and Only when a second deviation criterion describing a higher deviation is met is the adjustment device for mechanical tracking of the adjustment actuated, wherein if a mechanical limitation for the mechanical tracking of the adjustment is reached, any deviation beyond that is at least partially compensated for by electronic tracking of the adjustment.

It is proposed to maximize the availability of radar sensors by using position sensors, which are preferably rigidly connected to the radar sensors. By using position sensors, a position adjustment of the radar sensor, for example triggered by a collision-related deformation and / or a modification, can be recognized very quickly. If a deviation from the target installation position of the radar sensor is detected, the adjustment can be tracked, which, however, is advantageously not possible in the present case solely by mechanical adjustment by means of the adjustment device, but first in the case of minor deviations in the form of electronic tracking, in particular electronic correction by means of a correction angle. If such an electronic adjustment of the adjustment is no longer possible or is no longer sufficient, ie if a second deviation criterion describing a higher deviation is met, an electromechanical adjustment of the radar sensor and thus a mechanical adjustment of the adjustment can also be provided. The adjustment device can in particular comprise a controllable motor and / or the adjustment device can be arranged on a holding device of the radar sensor.

It is therefore essentially proposed to combine mechanical and electronic options for tracking the adjustment. With a readjustment that is controlled solely by a motor, for example after an accident when the adjustment device is damaged, it is no longer possible to guarantee that the radar sensor functions correctly after the radar sensor itself has received no information that it is misaligned. If an adjustment device fails, the electronic adjustment of the adjustment can also serve as a fallback level. In particular, it is advantageous within the scope of the invention that ultimately only one area of high deviations, in particular an extreme area, is corrected by the electromechanics of the adjusting device, while otherwise an electronic adjustment of the adjustment is used without stressing the adjusting device, so that wear of the Adjustment device is significantly reduced.

Specifically, the electronic adjustment of the adjustment can be carried out by beamforming and / or correcting an error in the radar data of the radar sensor caused by the deviation. For example, the detection range of the radar sensor can be adaptable on the basis of a corresponding configuration and / or activation of the antenna arrangement of the radar sensor, whereby other types of beamforming can also be used, for example to “tilt” the detection range, so to speak, when the radar sensor is tilted. Additionally or alternatively, an electronic misalignment correction can also be carried out on the radar data, for example measured angles in the radar data can be corrected by a correction angle, which can be described by the deviation.

The first deviation criterion can be designed in such a way that it defines a deviation range in which a purely electronic correction of a misalignment takes place. For example, the first deviation criterion can define at least one angular range, which can have a lower limit in the range of, for example, 0.2-0.7 ° and / or an upper limit in the range of 4-6 °. Embodiments are conceivable in which both the first and the second deviation criterion are fulfilled at the same time, whereupon a control unit performing the method can determine a corresponding combined electronic and mechanical adjustment of the adjustment. If, for example, larger misalignment angles, described by the deviation, occur, for example in the range of more than 5 °, in particular 8 °, the second deviation criterion can be fulfilled by way of example.

It is particularly advantageous, however, that mechanical adjustment of the adjustment is only carried out when electronic adjustment of the adjustment is no longer necessary, so that the second deviation criterion can preferably monitor exactly this. In a particularly expedient embodiment of the present invention, it can be provided that the second deviation criterion is met if, according to the described deviation, a minimum detection area of the radar sensor is no longer contained in a detection area of the radar sensor that is currently possible through electronic adjustment of the adjustment. This means that a minimum detection range of the radar sensor is defined, which is necessary for sufficient performance of the radar sensor with regard to the detection of the surroundings of the motor vehicle. If it now turns out that this minimum detection range is no longer completely contained in the detection ranges currently possible by adapting operating parameters and / or evaluation parameters of the radar sensor, a limit of the possibilities of the electronic adjustment of the adjustment has thus been reached. It is then expedient to restore the possibility of scanning the minimum detection area by mechanically adjusting the adjustment. In this case, a mechanical correction can be provided when the radar sensor cover is no longer sufficient.

In an expedient embodiment of the invention, it can be provided that the determined deviations and / or the tracking measures, in particular in a memory of the radar sensor, are logged. In particular, it can also be provided that during a mechanical adjustment of the adjustment, a new target installation position is defined as the installation position existing after the mechanical adjustment, in particular if the original target installation position can no longer be completely achieved. Through the logging, for example when servicing and / or repairing the motor vehicle, it is easy to understand whether and which corrective measures have been carried out due to misalignment. In particular, it is also useful if it is known within the radar sensor itself that such a readjustment has been carried out, since this can possibly have an influence on an own assessment of the quality of the own radar data. The proposed logging therefore provides a better information base within the motor vehicle which can be used in different ways.

A particularly advantageous embodiment of the present invention provides that the adjustment is carried out by a control unit of the radar sensor implemented in particular in semiconductor technology. In this way, the adjusting device, the at least one position sensor and the radar sensor with the control unit carrying out the method according to the invention create a self-adjusting radar system which, in particular, directly implements the electronic adjustment of the adjustment and also, if provided, particularly easy to implement logging enabled in the radar sensor.

In the context of the present invention, configurations are also conceivable in which at least the electronic adjustment of the adjustment takes place at least essentially in real time. A temporary change in the installation position of the radar sensor, for example due to the wind, can also be sensed by the at least one position sensor, in particular in the form of an acceleration sensor. The correction can then be carried out at least essentially in real time, preferably electronically, but possibly also mechanically.

In an expedient development of the method according to the invention, it can be provided that, when determining the deviation, in addition to the sensor data of the position sensors, radar data relating to an evaluation criterion are also evaluated in a supplementary and / or plausible manner. This means that the evaluation of radar data relating to certain surrounding objects, for example guard rails or the like, already described at the beginning of the prior art, can be used as a supplement and / or to make the plausibility check in order to increase the overall quality of the adjustment adjustment. While such a procedure, as shown, basically appears to be rather slow and thus unsuitable for maximum availability of the radar sensors, it can nevertheless have an improving influence on tracking options that act more quickly.

According to the invention, when a mechanical limitation for the mechanical adjustment of the adjustment is reached, a deviation going beyond this is at least partially compensated for by electronic adjustment of the adjustment. For example, a mechanical change in the installation position of the radar sensor can be structurally limited, so that a deviation can possibly only be compensated to a certain extent by the adjustment device. Here, it is also particularly advantageous to use two variants of the compensation of the misalignment, after these can also be used to complement one another, in order to thus expand the overall range in which the misalignments can be compensated or corrected.

In an expedient development, at least one acceleration sensor, in particular measuring relative to gravitational acceleration, is used as the position sensor. Such acceleration sensors are already known in principle, for example from inertial platforms in motor vehicles, and can also be used expediently within the scope of the present invention. In particular, if corrections are to be made essentially in real time, for example in the event of strong winds, such acceleration sensors can deliver highly accurate position data. At this point, it should also be generally noted that other current operating data of the motor vehicle, which may have an influence on a measurement of the at least one position sensor, may be used and taken into account when evaluating the sensor data, for example if one measures relative to the acceleration due to gravity Inclination of the mobile surface and / or the mobile body. In particular, a reference can be made to other position sensors fixed to the motor vehicle or their sensor data.

Of course, however, it is also conceivable to use position sensors, for example, which relate directly to the position relative to a body component of the motor vehicle or the like.

In addition to the method, the invention also relates to a motor vehicle having a radar sensor, at least one position sensor that is motion-coupled, in particular rigidly connected, to the radar sensor, a mechanical adjustment device assigned to the radar sensor, and a control unit designed to carry out the method according to the invention. The control unit can in particular be part of the radar sensor. The radar sensor is preferably designed in semiconductor technology, in particular CMOS technology, which means that the radar sensor can have a semiconductor chip, in particular a CMOS chip, which realizes the radar transceiver. The control unit of the radar sensor and / or a digital signal processing component of the radar sensor can also be realized by the semiconductor chip. The semiconductor chip can be present in a package with an antenna arrangement of the radar sensor.

All statements regarding the method according to the invention can be transferred analogously to the motor vehicle according to the invention and vice versa, so that the above-mentioned advantages can be obtained with both objects.

• 1 eine Prinzipskizze eines erfindungsgemäßen Kraftfahrzeugs,
• 2 eine Prinzipskizze zur Radarsignalverarbeitung mit einer elektronischen Nachführung der Justage,
• 3 ein Zusammenhangsdiagramm zur mechanischen Nachführung der Justage,
• 4 eine Explosionszeichnung einer möglichen Ausführung eines Radarsystems mit Verstelleinrichtung, und
• 5 eine Skizze zur Erläuterung des erfindungsgemäßen Verfahrens.

Further advantages and details of the present invention result from the exemplary embodiments described below and from the drawing. Show:

• 1 a schematic diagram of a motor vehicle according to the invention,
• 2nd a schematic diagram for radar signal processing with an electronic adjustment of the adjustment,
• 3rd a relationship diagram for the mechanical adjustment of the adjustment,
• 4th an exploded view of a possible embodiment of a radar system with adjusting device, and
• 5 a sketch to explain the method according to the invention.

1 shows a schematic diagram of a motor vehicle according to the invention 1 . There are three radar sensors in the present case 2nd , 3rd shown, the motor vehicle 1 can of course also have further radar sensors in which the adjustment described below is given. The radar sensor 2nd is hidden behind a front bumper 4th installed in an installation position in an installation position. The radar sensors are corresponding 3rd hidden behind a rear bumper 5 installed. With the radar sensor 2nd is a long-range radar sensor 2nd while the radar sensors 3rd are designed as medium-range radar sensors. The radar sensors 2nd , 3rd are implemented in CMOS technology and each have a package in which an antenna arrangement of the respective radar sensor 2nd , 3rd and a semiconductor chip are included. The semiconductor chip realizes the radar transceiver, a digital signal processing component and an in 1 also shown control unit 6 of the respective radar sensor 2nd , 3rd .

The radar data of the radar sensors 2nd , 3rd can from different, only roughly indicated vehicle systems 7 can be used for different functions.

Over time, various effects can change the installation position of the radar sensors 2nd , 3rd inside the motor vehicle 1 come, so that in particular angle measurements with respect to the generally used coordinate system of the motor vehicle 1 can be faulty. This applies in particular to the long-range and medium-range radar sensors shown here 2nd , 3rd , since even small angle adjustments can lead to clearly noticeable deviations.

Causes of such a change in the installation position can be, for example, aging effects, temperature influences and / or collisions of various degrees.

To ensure the performance of the radar sensors despite such changes in the installation position 2nd , 3rd The control units are to be maintained as far as possible 6 also trained to carry out the method according to the invention. This is done with each of the radar sensors 2nd , 3rd a position sensor designed as an acceleration sensor 7 rigid, i.e. motion-coupled, connected. This delivers its sensor data to the control unit 6 in order to derive a deviation from the target installation position from them. Furthermore, each of the radar sensors 6 an adjustment device 8th associated with a motor by the control unit 6 is controllable and for tilting the respective radar sensor 2nd , 3rd , in particular in two levels.

According to the method according to the invention, if there is a discrepancy from the target installation position, there are two possibilities for carrying out the adjustment, and therefore continue to be able to deliver high-quality radar data that is compensated for the change in the installation position. On the one hand, an electronic correction, that is to say adjustment of the adjustment, can be carried out by beamforming and / or correction in the radar data itself 2nd explained in more detail in an exemplary embodiment.

The process of pre-processing in the radar sensors 2nd , 3rd , indicated by the box 9 , broken down in more detail. From the radar front end 10th the measured radar signals are obtained and in various preprocessing measures, indicated by the boxes 11 and 12th , pre-processed. Such preprocessing steps include, for example, basic signal processing steps, Fourier transforms (FFT) and the like. A step shown separately here is the so-called angle estimation, see box 13 , in which angles are to be determined as precisely as possible for detected objects.

These angles are most influenced by the change in the installation position, so that from the sensor data of the position sensors 7 and consequently the deviation that can be derived from this on the part of the control unit 6 an angle correction 14 can be determined and applied to the corresponding estimated angles. The radar data is then generated together with this correction 15 which, for example, postprocessing steps 16 and / or their evaluation in the vehicle systems 17th can be supplied.

At this point it should be noted that the radar data 15 can also go into the determination of the deviation from the target installation position in a supplementary and plausible manner by, for example, observing the chronological sequence of certain surrounding objects that fulfill an evaluation criterion when the motor vehicle is moving.

3rd illustrates the essential procedure for a mechanical adjustment of the readjustment. Again, in the control unit 6 the sensor data of the position sensors 7 evaluated for a deviation, from which an adjustment instruction for the motor of the adjustment device 8th Can be derived as control data from the control unit 6 to the adjustment device 8th is directed.

4th shows a possible concrete implementation of the bracket of a radar sensor 2nd , 3rd more accurate. The radar sensor can 2nd , 3rd in a holding device 18th to be included over the the engine 19th having adjustment device 8th can be attached to the motor vehicle, for example to a body part or a bumper part.

5 now explains the use of both electronic tracking and mechanical tracking of the adjustment provided according to the invention. There is one step 20th checks whether a first and / or a second deviation criterion, which evaluates the deviation, is fulfilled. The first deviation criterion is already met with a smaller deviation than the second deviation criterion. The definition can be made, for example, via the deviation angle, so that, for example, the first deviation criterion is always met when the deviation angle is more than a first limit value, for example a limit value in the range of 0.2-0.7 °. A higher deviation angle of the installation position may then be required for the second deviation criterion, for example greater than 5 °. It is particularly preferred, however, to use the second deviation criterion to specifically focus on changes in the installation position that can still be compensated electronically, so that the second deviation criterion can preferably be used to check whether a minimum detection range of the radar sensor is present in the current mechanical installation position 2nd , 3rd can still be guaranteed. If this is not the case, the second deviation criterion is fulfilled.

If only the first deviation criterion is met, this is done in one step 21 even an electronic adjustment of the adjustment. Only if the second deviation criterion is also fulfilled is the adjustment made mechanically in one step 22 , which can also be supplemented by an additional electronic adjustment, especially if the high-quality operation of the radar sensor can only be achieved by combining the two correction options 2nd , 3rd can be ensured. If tracking is no longer possible at least within a certain range, the corresponding radar sensor can 2nd , 3rd can also be deactivated and a corresponding error message issued.

In the present case, each readjustment process is also carried out in a memory of the control unit 6 logged and can therefore be tracked.

Claims (9)

Method for tracking the adjustment of a radar sensor (2, 3) in a motor vehicle (1), at least one position sensor (7) coupled to the radar sensor (2, 3) being used to determine a current position of the radar sensor (2, 3), by evaluating sensor data of the position sensor (7) to determine a deviation from a target installation position of the radar sensor (2, 3) and adjusting the adjustment on the basis of this deviation, the radar sensor (2, 3) having a mechanical, controllable adjusting device (8 ) of the motor vehicle (1), characterized in that when a first deviation criterion describing a lower deviation is met, only electronic adjustment of the adjustment by adapting the control of the radar sensor (2, 3) and / or evaluating radar data (15) the radar sensor (2, 3) is carried out and the Ve only when a second deviation criterion describing a higher deviation is met adjusting device (8) for mechanical adjustment of the adjustment is actuated, wherein if a mechanical limitation for the mechanical adjustment of the adjustment is reached, any further deviation is at least partially compensated for by electronic adjustment of the adjustment. Procedure according to Claim 1 , characterized in that the electronic adjustment of the adjustment is carried out by beamforming and / or correcting an error in the radar data (15) of the radar sensor (2, 3) caused by the deviation. Procedure according to Claim 1 or 2nd , characterized in that the second deviation criterion is met if, according to the described deviation, a minimum detection area of the radar sensor (2, 3) is no longer contained in a detection area of the radar sensor (2, 3) that is currently possible through electronic adjustment of the adjustment. Method according to one of the preceding claims, characterized in that the determined deviations and / or the tracking measures, in particular in a memory of the radar sensor (2, 3), are logged. Method according to one of the preceding claims, characterized in that the calibration is carried out by a control unit (6) of the radar sensor (2, 3), which is implemented in particular in semiconductor technology. Method according to one of the preceding claims, characterized in that at least the electronic adjustment of the adjustment takes place at least substantially in real time. Method according to one of the preceding claims, characterized in that, in determining the deviation, in addition to the sensor data of the position sensors, radar data (15) relating to an object fulfilling an evaluation criterion are also supplemented and / or checked for plausibility. Method according to one of the preceding claims, characterized in that at least one acceleration sensor, in particular measuring relative to gravitational acceleration, is used as the position sensor (7). Motor vehicle (1), comprising a radar sensor (2, 3), at least one position sensor (7) coupled to the radar sensor (2, 3), a mechanical adjustment device (8) assigned to the radar sensor (2, 3) and one for carrying out a method Control unit (6) designed according to one of the preceding claims.

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