Sensor Apparatus for a Vehicle, Vehicle, Method for Operating a Sensor Apparatus

Abstract

The disclosure relates to a sensor apparatus for a vehicle, in particular a motor vehicle, having at least one sensor for detecting operational values of the vehicle while driving on a roadway, having a checking device for monitoring the functional capability of the at least one sensor. There is provision that the checking device has at least one communication device which is designed to detect a reference means in the surroundings of the vehicle during driving, and a control unit which compares an output signal of the sensor with an expected setpoint output signal as a function of a detected reference means, in order to determine the functional capability of the sensor.

Claims

1. A sensor apparatus for a vehicle, the sensor apparatus comprising: at least one sensor configured to detect operational values of the vehicle while driving on a roadway; and a checking device configured to monitor a functional capability of the at least one sensor, the checking device including: at least one communication device configured to detect a reference in a surroundings of the vehicle during driving; and a control unit configured to determine the functional capability of the at least one sensor by comparing an output signal of the at least one sensor with an expected setpoint output signal as a function of the detected reference.

2. The sensor apparatus according to claim 1, the at least one communication device comprising: at least one camera device configured to optically detect at least one visual mark as the reference in the surroundings of the vehicle.

3. The sensor apparatus according to claim 1, the at least one communication device comprising: at least one radio module configured to wirelessly communicate with at least one stationary communication device as the reference in the surroundings of the vehicle.

4. The sensor apparatus according to claim 1, the at least one communication device comprising: at least one magnetosensitive sensor module configured to interact with at least one of (i) at least one magnetic marking and (ii) at least one electrical marking as the reference in the surroundings of the vehicle.

5. A vehicle comprising: a sensor apparatus comprising: at least one sensor configured to detect operational values of the vehicle while driving on a roadway; and a checking device configured to monitor a functional capability of the at least one sensor, the checking device including: at least one communication device configured to detect a reference in a surroundings of the vehicle during driving; and a control unit configured to determine the functional capability of the at least one sensor by comparing an output signal of the at least one sensor with an expected setpoint output signal as a function of the detected reference.

6. A method for operating a sensor apparatus for a vehicle, the method comprising: detecting, with at least one sensor of the sensor apparatus, operational values of the vehicle while driving on a roadway; and monitoring, with a checking device of the sensor apparatus, a functional capability of the at least one sensor, the monitoring comprising: detecting, with at least one communication device of the checking device, a reference in a surroundings of the vehicle during driving; and determining, with a control unit of the checking device, the functional capability of the at least one sensor by comparing an output signal of the at least one sensor with an expected setpoint output signal as a function of the detected reference.

7. The method according to claim 6, the detecting of the reference in the surroundings of the vehicle further comprising: detecting the reference with at least one of (i) at least one camera device of the at least one communication device, (ii) at least one radio module of the at least one communication device, and (iii) at least one magnetosensitive sensor module of the at least one communication device.

8. The method according to claim 6, the determining of the functional capability further comprising: starting the comparing of the output signal with the expected setpoint output signal in response to a first reference being detected; and ending the comparing of the output signal with the expected setpoint output signal in response to a subsequent second reference being detected.

9. The method according to claim 6, the determining of the functional capability further comprising: increasing a sensitivity of the at least one sensor during the comparing of the output signal with the expected setpoint output signal.

10. The method according to claim 6, the detecting of the reference in the surroundings of the vehicle further comprising: detecting as the reference at least one of (i) a visual mark, (ii) a stationary communication device; (iii) a magnetic marking; and (iv) electrical marking, the reference being at least one of on and next to the roadway.

11. The sensor apparatus according to claim 1, wherein the vehicle is a motor vehicle.

12. The vehicle according to claim 5, wherein the vehicle is a motor vehicle.

13. The method according to claim 6, wherein the vehicle is a motor vehicle.

14. The method according to claim 9, the increasing of the sensitivity of the at least one sensor further comprising: reducing a triggering threshold value as a function of the expected setpoint output signal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Further advantages and preferred features and combinations of features arise, in particular, from what has been described above. The disclosure will be explained in more detail below on the basis of the drawing, in which:

[0018] FIG. 1 shows a vehicle with an advantageous sensor apparatus on a roadway in a simplified illustration, and

[0019] FIG. 2 shows a diagram explaining a method for operating the sensor apparatus.

DETAILED DESCRIPTION

[0020] FIG. 1 shows a simplified illustration of a vehicle 1 which is moving along a roadway 2. According to the present exemplary embodiment, the roadway 2 leads here into a tunnel 3.

[0021] The vehicle 1, which as a motor vehicle has an electrical drive device or a drive device in the form of an internal combustion engine is also provided with a plurality of sensors 4, 5 which during the ongoing driving mode of the vehicle 1 detect operational values which are evaluated or used to increase the comfort or the driving safety of the vehicle 1. In this way, for example the sensor 4 detects, as an acceleration sensor, lateral forces which act on the vehicle 1, in order to initiate safety braking when required, and the sensor 5 detects the brightness of the ambient light, as a function of which a headlight device and/or interior lighting of the vehicle 1 are/is actuated.

[0022] The output signals of the sensors 4, 5 are compared, in particular by means of a comparison with predefinable threshold values by one or more control units 6, in order to be able to decide about the control of the headlight device or, for example, a brake device when excessively high lateral forces occur. In particular, the output signals are evaluated by a central control unit 6, for example an ESP control unit. Alternatively it is possible to provide that at least some of the output signals are evaluated by control units of the sensors 4, 5 themselves. The sensors 4, 5 form in this respect, together with the control unit 6 a sensor apparatus 7 of the motor vehicle.

[0023] The sensor apparatus 7 also has a checking device 8 which is designed to monitor the functional capability of the sensors 4, 5, with the result that incorrect triggering or faulty failure to trigger can be avoided in that, for example, a system for which the respective sensor 4, 5 supplies a calculation value is switched to a safe state.

[0024] The checking device 8 has a communication device 9 which is designed to detect reference means in the surroundings of the vehicle. According to one exemplary embodiment there is provision that the communication device 9 is embodied as a camera device which monitors the surroundings visually for reference means.

[0025] According to the present exemplary embodiment there is provision that visual marks 10 are arranged spaced apart from one another in the direction of travel as reference means on the edge of the road in such a way that they can be detected visually by the camera device or the communication device 9. The marks 10 define or delimit a reference section along which the vehicle 1 moves during the further driving. As soon as the vehicle 1 passes the first reference means or the first mark 10, and the latter is detected by the camera device, a checking process for one or both of the sensors 4, 5 is started, during which process the output signals of the sensors 4 and/or 5 are compared with a respective setpoint output signal.

[0026] FIG. 2 shows in this respect the signal profile S1 of the output signal of the sensor 4 plotted against the time T in a diagram. During normal operation, the output signal of the sensor 4 is compared with the threshold value SW. If the output signal S1 exceeds the threshold value SW, a fault is identified. In order to be able to take into account, in particular, external influences during the threshold value comparison while driving, with the result that said influences do not immediately bring about a triggering result, if the threshold value SW is set to a correspondingly high value, in order to avoid detecting a fault whenever the output signal increases.

[0027] As soon as the vehicle 1 has detected the first mark 10 by means of the communication device 9, the threshold value SW is reduced to a lower checking threshold value SW.sub.P for the purpose of checking, as shown by a dashed line in FIG. 2. The sensor 4 has therefore been switched to a more sensitive setting for the checking process described below.

[0028] With the detection of the first mark 10, a comparison of the output signal S1 with a reference signal R1 starts, said reference signal R1 representing a setpoint output signal of the sensor 4 which should be generated when the reference section following the first mark 10 is travelled along by the sensor 4. The setpoint output signal is loaded here, for example, from a non-volatile memory of the sensor 4 or of the control unit 6 when the first mark 10 is detected. It is also conceivable that the setpoint output signal is selected as a function of the detected mark 10 or the detected reference means from a characteristic field, in order to obtain a setpoint output signal which is suitable for the application. During the comparison, the output signal S1 is compared with the reference signal R1 and checked for deviations. If the output signal S1 differs from the setpoint output signal over a predetermined value or range, it is identified that the sensor 4 has a fault or defect.

[0029] In the present case, the first mark 10 is followed by a straight roadway section, with the result that no lateral accelerations which could lead to a deflection of the output signal should act on the sensor 4. However, in the exemplary embodiment shown in FIG. 2 the output signal S1 has a sensor fault SF which cannot be caused by external influences owing to the straight section of road. The setpoint output signal corresponds to the expected output signal of the sensor during the straight-ahead travel. The comparison of the output signal S1 with the reference signal R1 is therefore informative with respect to the functional capability of the sensor 4 during the travel along the known reference section.

[0030] The comparison is preferably carried out with the detection of the first mark 10 for a predetermined time or a predetermined distance. As an alternative the comparison is ended when a second mark 10 is detected by means of the communication device 9. The reference section is therefore defined by the reference means or the marks 10 themselves.

[0031] As an alternative to the detection of visual marks 10 at the edge of the roadway it is, for example, also possible to detect a visual mark 11 such as is provided at the input of the tunnel 3. Therefore, for example the output signal of the sensor 5 can, for the purpose of detecting the ambient brightness, be compared with a setpoint output signal which should be waited for when traveling through a tunnel.

[0032] Furthermore, it is conceivable for the communication device 9 to have a radio module which can communicate with a stationary communication device 12 when travelling past, for example by WLAN or some other close-range radio technology. By means of the communication between the radio module and the stationary communication device 12 it is possible for data to be transmitted both from the vehicle 1 to the communication device 12 and vice versa. As a result, it can for example be ensured that the communication device 9 detects the communication device 12 and interrogates one or more setpoint output signals for the subsequent reference section, which is then sent by the communication module 12 to the communication device 9, where they are used for the following comparison. Alternatively, the communication serves merely for starting and ending the comparison or for characterizing the start and/or end of the reference section.

[0033] It is also possible to provide that magnetic or else electromagnetic markings 13, over which the vehicle 1 is moved when traveling straight ahead, are inserted into the roadway. The communication device 9 correspondingly has a magnetosensitive module for detecting the markings 13. The first marking 13 defines the start and the second marking 13 defines the end of the reference section. During the comparison of the output signal with the setpoint output signal the procedure here is as described above.

[0034] The checking of the sensor 5 is expediently performed in a corresponding way by the checking device 8.

[0035] By means of the advantageous method and the advantageous checking apparatus it is ensured that the vehicle is informed that it is on a section of road which is defined as a reference section or can be used as a reference section. These are, in particular, parts of a section of a freeway without damage or other road works or incidents. An example would also be travel through a tunnel or straight-ahead travel, as described above. Basically, the communication with the surroundings can be carried out visually by means of the detection of a specific code or mark 10 at the edge of the road and/or in the center of the roadway or next to the roadway 2 by means of the camera device or the radio module or the magnetosensitive module. The sensors on the reference section must each generate an output signal which lies within predefinable limits or within a predefinable threshold value SW with respect to a setpoint output signal. Therefore, for the comparison the threshold value SW which is used during normal operation is reduced to the checking threshold value SW.sub.P as already described, said checking threshold value SW.sub.P being dependent on the setpoint output signal, with the result that it is not exceeded by the setpoint output signal. If the actual output signal S1 then exceeds the checking threshold value SW.sub.P, a fault of the respective sensor 4, 5 is inferred. The knowledge about the reference section which, by means of the communication device which ultimately constitutes a vehicle-to-X interface, permits it to switch the fault detection limits to a more sensitive setting while driving along the reference section, such as, for example, by adapting the threshold value SW to the checking threshold value SW.sub.P. When the comparison ends, the checking threshold value SW.sub.P is switched back to the normal value SW and the sensor is therefore switched to a robust setting as soon as the reference section has been passed through.

[0036] The core of the method is therefore the detection of sensor faults by reprogramming or adapting a fault detection function by means of the control unit 6, or alternatively in the sensors 4,5 themselves, during travel on the reference section, which is detected by the communication device 9. This approach permits a relatively large class of faults to be detected in a short time by virtue of the fact that a current driving state is taken into account during the checking of a sensor. By virtue of the communication device 12, the detection takes place during driving, with the result that checking can be carried out regularly or when necessary. The start or the end of a reference section is preferably communicated to all the control units of the vehicle for example via a BUS, with the result that said control units can always adapt their checking strategies.

[0037] If a sensor fault is detected during the checking, the sensor 4, 5 or a system which uses the sensor is preferably deactivated or switched to a safe state. Additionally or alternatively, an entry is made in a control unit 6 so that at the next visit to a workshop the control unit 6 and/or the sensor 4, 5 can be checked more precisely. A warning lamp for the driver of the vehicle 1 can also be actuated as a result of the fault detection.