DE102015005570A1 - Method for adjusting and / or calibrating an environmental sensor, environment sensor and motor vehicle - Google Patents

Abstract

Method for adjusting and / or calibrating an environmental sensor (4), which is installed in a motor vehicle (1) positioned in a first reference position (3) and has a sensor element (9) and an inertial sensor (10) coupled to it with respect to a desired value Alignment (5) with respect to the first reference ply (3), wherein the inertial sensor (10) is calibrated with respect to a second reference ply whose position relative to the first reference ply (3) is known, comprising the following steps:
- Detecting measured values by means of the inertial sensor (10) and determining an actual orientation of the sensor element (9) with respect to the first reference position (3) from the measured values; and
- Adjustment and / or calibration of the environmental sensor (4) to the desired orientation (5) in dependence on a deviation of the actual orientation of the target orientation (5).

Description

The invention relates to a method for adjusting and / or calibrating an environmental sensor. In addition, the invention relates to an environmental sensor and a motor vehicle.

Modern motor vehicles have one or more environmental sensors which serve to detect the surroundings of the motor vehicle and to evaluate the sensor data thus determined, for example in driver assistance systems. If a plurality of environmental sensors are provided in a motor vehicle, their sensor data are typically used to form an environmental model of the motor vehicle, which in turn can be accessed by different systems of the motor vehicle. For this purpose, an environmental sensor has a sensor element which is aligned with the environment of the motor vehicle to be detected. Such sensor elements may be, for example, cameras, laser, radar or ultrasonic sensors.

For proper operation of the environmental sensor its correct adjustment and / or calibration is of great importance. In this case, adjustment designates, in particular, a positioning and alignment of the environmental sensor subsequent to the mechanical installation, so that the sensor data acquired by it coincide as far as possible with a coordinate system on which the sensor data are processed further. On the other hand, calibration designates all further measures, in particular those of signal and / or data processing, which aim to match the acquired sensor data with this coordinate system. Typically, the environmental sensor is initially installed in the motor vehicle and adjusted and / or calibrated at the end of the production line. In the case of a later decalibration of the environmental sensor but also a new adjustment and / or calibration may be required as part of a customer service.

It is known to arrange reference objects or reference patterns (so-called targets) defined in the detection range of the sensor in the case of a defined motor vehicle and to perform the adjustment and / or calibration based on the detected sensor data of the target. For this purpose, however, care must be taken to an exact positioning of the motor vehicle to the target, which brings a lot of effort. In addition, in an adjustment and / or calibration in the context of customer service targets in different places, such as workshops, must be held, which creates additional logistical costs and ultimately high costs.

The invention is thus based on the object of specifying a method for adjusting and / or calibrating an environmental sensor, which is easier to perform and in particular dispenses with the use of any targets.

To achieve this object, according to the invention, a method for adjusting and / or calibrating an environmental sensor, which is installed in a motor vehicle positioned in a first reference position and has a sensor element and an inertial sensor coupled thereto, is provided with respect to a desired orientation with respect to the first reference position, wherein the inertial sensor is calibrated with respect to a second reference position whose position relative to the first reference position is known, comprising the following steps: acquiring measured values by means of the inertial sensor and determining an actual alignment of the sensor element with respect to the first reference position from the measured values; and adjusting and / or calibrating the environmental sensor to the desired orientation in response to a deviation of the actual orientation from the target orientation.

In the context of such a method, the environmental sensor has, in addition to its sensor element, an inertial sensor which is coupled with it in movement, in particular fixedly attached thereto. The inertial sensor is designed to detect its position in one or more spatial directions. Such inertial sensors are known per se from the prior art and in particular are so small in size and cost-effective that they can be position-coupled with the sensor element with little design effort. For example, in the context of the production of the environmental sensor while the inertial sensor is calibrated to a second reference position, which is known in the implementation of the method.

After installation of the environmental sensor in the motor vehicle, so a rather rough positioning with usually occurring deviations, the motor vehicle is brought into a predetermined first reference position, wherein a reference between the first reference position and he second reference position is given. Of course, the first reference position and the second reference position may also be identical. Appropriately, the horizontal is selected for the first reference position and / or the second reference position. Based on this initial configuration, the method steps according to the invention are then carried out.

First, measured values are recorded by means of the inertial sensor with respect to its second reference position. From these, the actual orientation of the sensor element with respect to the first reference position is then determined. For this purpose, alignment information represented by the measured values is transmitted via the inertial sensor, and thus also via the sensor element, evaluated by a computing device and set with known from the prior art geometric transformation methods in relation to the first reference position, ie that of the motor vehicle, so that the actual orientation of the sensor element is determined. This present in data form actual orientation can then be read by a technician, for example, the environment sensor or displayed in the car or on an external diagnostic device. In particular, a specific adjustment instruction can also be determined and output from the alignments. It is also conceivable that the actual orientation to an automatic adjustment device, such as a robot, passed and evaluated by this.

In the second step of the method according to the invention, an adjustment, that is to say a mechanical fine alignment of the environmental sensor to the desired orientation as a function of a deviation of the actual orientation from the desired orientation, takes place as far as necessary. It makes sense that the deviation is continuously minimized, possibly in several iteration steps. The adjustment can be done for example manually by a technician or automated by the adjustment device. Of course, in the context of the method according to the invention at any further time points, a current actual orientation can be determined.

Alternatively or in addition to adjusting the environmental sensor, it is calibrated, that is to say the sensor data detected by it are brought into agreement with the desired orientation, whereby the deviation of the actual orientation from the desired orientation is also compensated here. For this purpose, the person skilled in the art can make use of corresponding calibration methods known in the prior art.

The method according to the invention can be further developed in that the adjustment is deemed to have taken place if at least one measure of deviation describing the deviation of the actual orientation from the desired orientation falls below a predefined threshold value. Thus, a threshold value is provided which is determined such that, when falling below it, a further, in particular manual, fine adjustment is no longer expedient. In particular, below this threshold, it is possible to eliminate the deviation of the actual orientation from the target orientation by calibration. It is therefore particularly preferred if the environmental sensor is first adjusted until the deviation measure falls below the threshold value and, after the calibration has taken place, the ambient sensor is calibrated. There is thus a two-stage adjustment and calibration procedure. The deviation measure describing the deviation of the actual orientation from the target orientation is expediently selected such that it has the properties of a (mathematical) standard. However, it is of course also possible to provide at least one deviation variable with a positive and negative value range, the adjustment being deemed to have taken place if the at least one deviation variable lies within predefined intervals.

It is particularly preferred if the amount of an angular difference between the desired orientation and the actual orientation in at least one plane spanned by two spatial directions and / or the amount of the smallest angle enclosed by the desired orientation and the actual orientation is used as a deviation measure is used. Accordingly, it may be provided on the one hand to take into account the deviation of the actual orientation from the desired orientation with respect to one or more, but preferably all three, spatial directions during adjustment. On the other hand, however, the adjustment can also take place until the smallest angle between the desired orientation and the actual orientation in any direction falls below the threshold value. Advantageously, a suitable deviation measure can thus be selected with regard to the various technical properties of possible sensor elements. In this case, in particular the respective structural design of a used Justagemechanismus is taken into account.

It is particularly advantageous in the context of the method according to the invention if the motor vehicle has an inertial measuring unit and, after the adjustment and / or calibration, an orientation of the sensor element relative to the orientation of the inertial measuring unit is determined and stored. Since modern motor vehicles already have an inertial measurement unit, for example for an electronic stability program, the orientation of the sensor element, in particular in the form of its actual orientation in the first reference position, can be related to the orientation of the inertial measurement unit of the motor vehicle also positioned in the first reference position become. This relative orientation of the sensor element represented, for example, by a data record relating to the three spatial directions can subsequently be stored in a memory device of the motor vehicle or the environmental sensor and retrieved at later points in time.

In a further development of this method, it may further be advantageously provided that, in the event of a deviation of an orientation of the sensor element detected at a later time relative to the orientation of the inertial measuring unit, deviation information is generated, wherein the Environment sensor recalibrated taking into account the deviation information and / or decalibration information for the driver of the motor vehicle is output. Since the orientation of the sensor element is known and stored relative to the orientation of the inertial measurement unit, a review of the calibration of the environmental sensor can take place at any later time, advantageously independently of the respective position of the motor vehicle at this time. On the basis of the generated deviation information can be determined whether the detected deviation can be corrected directly by recalibration or if a Dekalibrierungsinformation, for example via a display device of the motor vehicle, is output to the driver of the motor vehicle, for example, to stop him to visit a workshop in the environment sensor is readjusted and / or calibrated. Advantageously, the method thus also allows the determination of a decalibration or performing a recalibration in situations in which the use of a target is completely unrealistic, for example, when the motor vehicle is parked on a parking space outside a workshop in the public traffic area.

In addition, the invention relates to an environmental sensor for a motor vehicle, comprising a sensor element for detecting the surroundings of the motor vehicle, wherein the environmental sensor has a bearing-coupled with the sensor element inertial sensor, which is calibrated with respect to a second reference position. All embodiments of the method according to the invention can be analogously transferred to the environment sensor according to the invention, so that even with this already mentioned advantages can be achieved.

It is particularly useful in an environment sensor according to the invention, when the inertial sensor is an acceleration sensor. Such an acceleration sensor can be designed so that it detects the detection of the position of the sensor element in at least one, preferably in all three spatial directions.

It is also particularly advantageous if the sensor element is a camera, a radar sensor or a laser sensor. Such sensor elements have been used for a long time for environmental sensors in motor vehicles, so that an environmental sensor according to the invention with such a sensor element builds on a robust technological basis.

In addition, it is particularly preferred if the environmental sensor has a control device designed to carry out the method according to the invention. This can be realized, for example, by a microcontroller or an application-specific integrated circuit (ASIC). In particular, the computing device and / or calibration device and / or memory device mentioned in connection with the method can be realized by such a control device.

Finally, the invention also relates to a motor vehicle, which has at least one environment sensor according to the invention. For this purpose, both identical environmental sensors according to the invention and differently designed environmental sensors according to the invention can be used; in particular, different environmental sensors according to the invention can each have differently designed sensor elements.

Moreover, it is also conceivable that the motor vehicle according to the invention has a control device designed for carrying out the method according to the invention. In particular, the computer device and / or calibration device and / or memory device described in connection with the method according to the invention can be part of the motor vehicle-side control device. Moreover, it is also conceivable that at least one environmental sensor installed in the motor vehicle has a control device and the motor vehicle has a control device, wherein the tasks of the control device can be distributed to the control device on the environment sensor side and the control device on the motor vehicle side.

Incidentally, all statements on the method according to the invention and on the environmental sensor according to the invention can be analogously transferred to the motor vehicle according to the invention, so that the advantages already mentioned can also be achieved therewith.

Further advantages and details of the invention will become apparent from the embodiments described below and from the drawing. The drawings are schematic representations and show:

1 an embodiment of a motor vehicle according to the invention, comprising an environment sensor, and

2 a flowchart of an embodiment of a method according to the invention.

1 is a schematic diagram of an embodiment of a motor vehicle 1 which is on a surface 2 in a first reference position 3 is positioned. In the vehicle is on the rear side designed as a camera environment sensor 4 installed, which in a target orientation 5 regarding the first reference position 3 adjusted and calibrated. The motor vehicle also has a with the environmental sensor 4 connected control device 6 on, with which also an inertial measuring unit 7 and one in the passenger compartment of the motor vehicle 1 arranged display device 8th connected is.

The environmental sensor 4 is designed as a rear view camera and rear side in the vehicle 1 installed. It comprises a sensor element 9 in the form of a camera, with which an inertial sensor 10 is motion coupled by a fixed connection. The inertial sensor 10 comprises an acceleration sensor (not shown) which detects the position of the inertial sensor 10 capture and output represented by measured values. Due to the positional coupling of the inertial sensor 10 with the sensor element 9 these measurements describe the position of the sensor element 9 , The inertial sensor 10 is the manufacturer, so before installation in the vehicle 1 , are calibrated for a second reference position.

The control device 6 includes a computing device 12 , a calibration device 13 and a storage device fourteen whose function is described in more detail in the description of the method.

Alternatively, the controller 6 as a whole or partially within the environmental sensor 4 be educated.

2 shows a flowchart of an embodiment of a method for adjustment and / or calibration of the environmental sensor 4 , It starts in a step S1.

In a subsequent step S2 of the method, the inertial sensor detects 10 Measurement data of its position relative to the second reference position, to which it is calibrated, and passes them to the control device 6 further. Within these are the readings by the computing device 12 taking into account a known positional difference between the first reference position 3 and the second reference layer in an actual orientation (not shown) with respect to the first reference position 3 transformed. The computing device 12 further determines a deviation measure of the actual orientation from the target orientation 5 and gives this over the interface 15 to a to the controller 6 connected external diagnostic device (not shown) off. The deviation measure describes the deviation of the actual orientation from the target orientation 5 in the three spatial directions of the first reference position 3 in terms of amount.

In a following step S3, the environment sensor is adjusted by a technician with the aim of reducing the deviation measure. Alternatively, the adjustment can also take place by means of an automatic adjustment device or a robot.

In a step S4 it is checked whether the deviation measure, ie the deviations with respect to the three spatial directions of the first reference position 3 a threshold of 0.5 ° for each spatial direction. If this is not the case, then a return to step S2 takes place and a new actual orientation and a new deviation measure are determined. The steps S2 and S3 are iterated by the query in step S4 until the threshold is undershot and the adjustment is considered as done.

The process then proceeds to a step S5. In this step, the calibration device calibrates 13 the environmental sensor 4 depending on the deviation of the last detected actual orientation from the target orientation 5 , This will be the means of the environment sensor 4 recorded sensor data with a designated coordinate system in accordance.

In a step S6, the inertial measurement unit detects 7 the location of the first reference location 3 positioned motor vehicle 1 , wherein the computing device 12 the orientation of the sensor element 9 , ie the last detected actual orientation, relative to the orientation of the inertial measuring unit 7 determined and in the storage device fourteen stores.

In a following step S7, the actual orientation of the environmental sensor 4 determined again according to the step S2, wherein the motor vehicle 1 at this time no longer in the first reference position 3 must be located. Further, in step S7, the orientation of the inertial measurement unit 7 detected and the orientation of the sensor element 9 relative to the orientation of the inertial measurement unit 7 determined. The deviation of this determined relative orientation is compared with the relative orientation stored in step S6. In the presence of a deviation above a threshold of, for example, 0.1 ° in a spatial direction, deviation information is generated.

In a subsequent step S8, it is evaluated whether there is deviation information. If this is not the case, there is a return to step S7, so that regularly the orientation of the sensor element 9 relative to the orientation of the inertial measurement unit 7 is monitored. If, on the other hand, a deviation information is present, it is checked in step S8 whether this indicates a deviation caused by a recalibration of the sensor element 9 can be corrected or if it is so large that a readjustment by a technician must be made.

In the former case, a recalibration is carried out in a step S9 analogous to the procedure in step S5 and a subsequent return to step S7, so that the orientation of the environmental sensor 4 continues to be monitored. However, if the evaluation of the deviation information indicates that this deviation is too great for a recalibration, the method branches off after step S8 into a step S10 in which the control device 6 a decalibration information is generated, which via the display device 8th is issued and should cause the driver to visit a workshop.

The method then ends in a step S11.

Claims (11)

Method for adjusting and / or calibrating an environmental sensor ( 4 ), which in one in a first reference position ( 3 ) positioned motor vehicle ( 1 ) is installed and a sensor element ( 9 ) as well as an inertial sensor ( 10 ), with respect to a target orientation ( 5 ) with regard to the first reference position ( 3 ), wherein the inertial sensor ( 10 ) with respect to a second reference position whose position relative to the first reference position ( 3 ) is calibrated, comprising the following steps: - acquisition of measured values by means of the inertial sensor ( 10 ) and determining an actual orientation of the sensor element ( 9 ) with regard to the first reference position ( 3 ) from the measured values; and - adjusting and / or calibrating the environmental sensor ( 4 ) to the target orientation ( 5 ) as a function of a deviation of the actual orientation from the desired orientation ( 5 ). A method according to claim 1, characterized in that the adjustment is considered to have taken place if at least one of the deviation of the actual orientation of the target orientation ( 5 ) deviation below a predefined threshold. Method according to Claim 2, characterized in that the amount of deviation of an angle difference between the desired orientation ( 5 ) and the actual orientation in at least one plane spanned by two spatial directions and / or the amount of the smallest angle included by the target orientation and the actual orientation is used. Method according to one of the preceding claims, characterized in that the motor vehicle an inertial measuring unit ( 7 ) and after alignment and / or calibration an alignment of the sensor element ( 9 ) relative to the orientation of the inertial measurement unit ( 7 ) is determined and stored. A method according to claim 4, characterized in that in case of a deviation of a detected at a later time alignment of the sensor element ( 9 ) relative to the orientation of the inertial measurement unit ( 7 ) a deviation information is generated, wherein the environmental sensor ( 4 ) is recalibrated taking into account the deviation information and / or a decalibration information for a driver of the motor vehicle ( 1 ) is output. Environment sensor ( 4 ) for a motor vehicle ( 1 ) comprising a sensor element ( 9 ) for detecting the environment of the motor vehicle ( 1 ), characterized in that the environmental sensor ( 4 ) one with the sensor element ( 9 ) position-coupled inertial sensor ( 10 ) which is calibrated with respect to a second reference position. Environment sensor ( 4 ) according to claim 6, characterized in that the inertial sensor ( 10 ) is an acceleration sensor. Environment sensor ( 4 ) according to claim 6 or 7, characterized in that the sensor element ( 9 ) is a camera, a radar sensor or a laser. Environment sensor ( 4 ) according to one of claims 6 to 8, characterized in that it comprises a control device (11) for carrying out a method according to any one of claims 1 to 7 ( 6 ) having. Motor vehicle ( 1 ), characterized in that it comprises at least one environment sensor ( 4 ) according to one of claims 6 to 9. Motor vehicle ( 1 ) according to claim 10, characterized in that it comprises a control device (11) for carrying out a method according to any one of claims 1 to 7 ( 6 ) having.

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