Sensor system for a vehicle

Abstract

A sensor system for a motor vehicle is provided in which measurement signals from a large number of sensors (23-26) are evaluated exclusively in a central unit (20).

Description

[0001] The present invention relates to sensor systems for vehicles, in particular motor vehicles, vehicles equipped with such sensor systems and corresponding methods.

[0002] Modern vehicles usually have a large number of sensors installed which, for example, collect information about the vehicle's surroundings. Depending on the information collected by the sensors, messages can then be issued to a driver of the vehicle and / or the vehicle's driving behavior can be directly influenced.

[0003] For example, distance sensors, in particular ultrasonic sensors or microwave sensors, are used in parking aids to measure the distance of the vehicle equipped with the sensors to other vehicles or fixed obstacles in the vicinity of the vehicle and, depending on this, to inform the driver, for example in the form of a distance warning, or even to carry out a parking process fully or partially automatically.

[0004] Such a system is known, for example, from DE 10 343 175 A1. Here, distance measurement is carried out using several sensors coupled to an evaluation unit. The evaluation unit, in turn, is connected to an on-board computer, for example, via a vehicle's CAN bus.

[0005] A similar system is also known from EP 1293381 A2.

[0006] Another distance measurement system is known from US 2003 / 0128137 A1. Here, separate signal lines for each sensor used lead from an evaluation unit to a distributor, and from the distributor, the signal lines then run to the individual sensors. The individual sensors have a control system.

[0007] WO 2009 / 040155 A1 discloses a system in which a plurality of sensors are connected via a bus, which can synchronize with each other via the bus without a control unit.

[0008] DE 10 2008 024 963 A1 discloses a system in which a plurality of sensors are connected to an ASIC (Application Specific Integrated Circuit) interface unit, which can be integrated in a control unit.

[0009] Another sensor system for a vehicle with multiple sensors is known from EP 2 182 697 A1. Here, sensors communicate with a control system via a bus system, with the sensors themselves having control units.

[0010] US 2009 / 0 254 260 A1 discloses an adaptive vehicle guidance system. This system uses various sensors to detect an area in front of the vehicle during a moving journey.

[0011] Furthermore, EO 2 182 697 A1 discloses a method for controlling sensors, in particular for ultrasound-based environment detection systems, in a vehicle.

[0012] Furthermore, EP 1 293 381 A2 discloses a system for detecting and displaying the distance of vehicles to obstacles.

[0013] Another conventional sensor system for a vehicle is in Fig. 1. As an example, the sensor system of the Fig. 1 four sensors 13-16, for example ultrasonic sensors or microwave sensors for distance measurement, for example for a parking aid.

[0014] In addition, the sensor system of the Fig. 1 a control unit 10, which can be a general control unit of a corresponding vehicle or a control unit specifically configured for the sensor system. The control unit 10 comprises a microcontroller 12 and a transmitting / receiving unit 11 for communicating with the sensors 13-16 via lines 112-115. The sensors 13-16 also comprise a transmitting / receiving unit 17 for this purpose. In addition, the system of Fig. 1 Power supply lines 110, 111, via which the control unit 10 and the sensors 13-16 are supplied with power.

[0015] In addition, each of the sensors 13-16 comprises an application-specific integrated circuit (ASIC) 18, which, as shown in FIG. 1 for example for the sensor 16, can contain, in particular, a digital signal processor 19. This digital signal processor 19 can be used to evaluate measurement signals detected by the respective sensor. In the case of distance sensors, for example ultrasonic sensors or microwave sensors, echoes, i.e., reflections, can be detected as measurement signals using the digital sensor 19, and the signal processor 19 can then be used to calculate the travel times of the signals from the sensor to an object and back.

[0016] The running times thus recorded are then transmitted via lines 112-115 to the control unit 10, in which, for example, the microcontroller 12 then takes appropriate measures on the basis of the running times, for example by warning a driver about an obstacle and / or intervening in the driving behavior, for example by means of automatic steering, for example in order to carry out a parking maneuver.

[0017] The sensor system of the Fig. 1, the individual sensors 13-16 are constructed in a relatively complex manner, particularly due to the presence of the user-specific integrated circuit with a digital signal processor 19.

[0018] Accordingly, such sensors are relatively complex to manufacture. In addition, the system Fig. 1 a relatively complex cabling with the individual lines 112-115 is necessary.

[0019] It is therefore an object of the present invention to provide a sensor system for a vehicle and a corresponding method for operating such a sensor system, in which more cost-effective sensors can be used.

[0020] This object is achieved by a sensor system according to claim 1 and a method according to claim 8. The subclaims define further embodiments.

[0021] According to the invention, a sensor system for a vehicle is provided, comprising: a variety of sensors, and a central unit coupled to the plurality of sensors, wherein the sensor system is designed such that an evaluation of measurement signals from the plurality of sensors takes place exclusively in the central unit, wherein the sensors comprise a signal conditioning unit for adapting the measurement signals for transmission to the central unit, and the signal conditioning unit comprises a user-specific integrated circuit.

[0022] By centralizing the evaluation of the measurement signals in the central unit, the individual sensors can be manufactured more easily and therefore more cost-effectively.

[0023] To evaluate the measurement signals, the central unit can, for example, include a digital signal processor.

[0024] The sensors can include a signal conditioning device, for example, in the form of an application-specific integrated circuit, to convert the measurement signals acquired by the sensors into a form that can be sent to the central unit. Such signal conditioning can include, for example, filtering or analog-to-digital conversion.

[0025] Such signal conditioning devices are significantly less complex than devices required to evaluate individual measurement signals.

[0026] The coupling of the plurality of sensors with the central unit can be carried out in particular via a bus, for example a CAN bus, which simplifies the wiring.

[0027] In one embodiment, the sensors are distance sensors, for example for a parking aid.

[0028] According to the invention, a method for operating such a sensor system is further provided, comprising: Acquisition of measurement signals using a variety of sensors, Transmitting the measurement signals to a central unit, and Evaluation of the measurement signals exclusively in the central unit.

[0029] If the sensors are distance sensors, the evaluation of the measurement signals may in particular include identifying reflections in the measurement signals and calculating travel times.

[0030] The invention is explained in more detail below using exemplary embodiments with reference to the accompanying drawings. They show: Fig. 1 a sensor system according to the state of the art, Fig. 2 a sensor system according to an embodiment of the present invention, Fig. 3 a vehicle equipped with a sensor system according to an embodiment, and Fig. 4 a flowchart illustrating a method according to an embodiment of the invention.

[0031] In the following, exemplary embodiments of the present invention are explained in detail with reference to the accompanying drawings. The described exemplary embodiments serve merely to illustrate the invention and are not to be construed as limiting the scope of the invention.

[0032] Features of different embodiments may be combined with one another unless otherwise stated. On the other hand, a description of an embodiment with a plurality of features should not be interpreted as meaning that all of these features are necessary for practicing the present invention, since other embodiments may have fewer features and / or alternative features.

[0033] In Fig. 2 shows a sensor system according to an embodiment of the invention. The sensor system of Fig. 2 comprises four sensors 23, 24, 25, and 26. The sensors 23-26 can be, for example, distance sensors such as ultrasonic sensors or microwave sensors, which can be used, for example, in a parking aid. In other embodiments, other types of sensors can be used, for example, acceleration sensors, ambient temperature sensors, or sensors for monitoring road conditions. The number of four sensors 23-26 is also to be understood merely as an example, and more or fewer sensors can also be present.

[0034] In the embodiment of the Fig. 2, all sensors 23-26 are essentially constructed in the same way and comprise a transmitting / receiving unit 27 and an application-specific integrated circuit (ASIC) 28.

[0035] The transmitting / receiving unit 27 transmits signals via a bus 214, 215 and receives signals from the bus 214, 215. In particular, in the embodiment of the Fig. 2 Measuring signals, ie measured values, of the sensors 23-26 are transmitted via the bus 214, 215 to a central unit 20, for example a general control unit of the vehicle or a central unit provided specifically for the sensor system.

[0036] The bus 214, 215 can, for example, be a CAN bus of a motor vehicle equipped with the sensor system. For communication via the bus, the central unit 20 also has a transmitting / receiving unit 21.

[0037] Furthermore, the central unit 20 in the embodiment of the Fig. 2 includes a digital signal processor 22 for evaluating the measurement signals. In the illustrated embodiment, the measurement signals are evaluated exclusively in the central unit 20 and not in the individual sensors 23-26. In particular, in the case of distance sensors, echoes (i.e., reflections) in the measurement signals are identified in the central unit 20, the travel times of corresponding reflected signals are determined, and from this, for example, a distance to an obstacle is derived.

[0038] By contrast, the user-specific integrated circuits 28 of the sensors 23-26 merely perform signal conditioning, i.e., the measured values ​​acquired by the respective sensor in the form of measurement signals are converted into a form suitable for transmission via the bus 214, 215. For such signal conditioning, the user-specific integrated circuits 28 can, for example, comprise a mixer 213, filter 212, and an analog-to-digital converter 29, as shown by way of example for the sensor 26. The measurement signal is preferably conditioned such that the sampling theorem is not violated, even with the available bandwidth of the bus 214, 215. The analog-to-digital converter 29 converts the data into digital data and then transmits it in digital form via the bus 214, 215 to the central unit 20.

[0039] In the central unit 20, all recorded measurement signals of the current measurement cycle and, if applicable, previous measurement cycles are available and can be evaluated centrally.

[0040] Evaluation of the measurement signals refers, in particular, to obtaining information from the measurement signals, for example, obtaining travel times including identifying reflections. In contrast, the above-mentioned signal conditioning does not extract any information from the measurement signals, i.e., the raw data; rather, it merely adapts them to enable transmission to the central unit.

[0041] Thus, in the embodiment of the Fig. 2 compared with the sensor system according to the state of the art of Fig. 1, which was described in the introduction, requires fewer complex sensors, which significantly reduces the costs for the sensors. Although a correspondingly powerful processing unit, such as the digital signal processor 22, must be provided in the central unit 20, this is only required once in the central unit, thus enabling overall cost savings.

[0042] It should be noted that the central unit 20 may also contain components other than a digital signal processor for signal processing, for example, a general, appropriately programmed microprocessor. If necessary, other signal conditioning units may also be provided in the sensors 23-26, for example, user-specific integrated circuits comprising components other than components 29, 212, 213, or even circuits other than user-specific circuits.

[0043] In Fig. 3 shows a vehicle 35 which is equipped with a sensor system according to an embodiment of the present invention, wherein the sensor system can be configured, for example, as described with reference to Fig. 2 can be implemented. The sensor system of the Fig. 3 serves as a parking aid. For this purpose, the sensor system of the Fig. 3 four distance sensors 31A-31D (hereinafter collectively referred to as distance sensors 31), which are arranged, for example, in a front bumper 30, and four distance sensors 32A-32D (hereinafter collectively referred to as distance sensors 32), which are arranged, for example, in a rear bumper of the vehicle 35. The sensors 31 and 32 can comprise, for example, ultrasonic sensors and / or microwave sensors, but also optical sensors.

[0044] The number of four sensors 31 and four sensors 32 is chosen merely as an example, and any suitable number of sensors can be used. Furthermore, the number of sensors 31 does not have to match the number of sensors 32. The positioning of the sensors is also to be understood merely as an example. For example, the sensors 32 can also be arranged entirely or partially in a tailgate of the vehicle 35.

[0045] The sensors 31, 32 are coupled to a central unit 30 via a bus 33.

[0046] Power supply lines 210, 211 supply power to the sensors 23-26 and the central unit 20.

[0047] In particular, only signal conditioning, i.e., adaptation of the detected measurement signals for transmission via the bus 33 to the central unit 30, can take place in the sensors 31, 32, while evaluation of the measurement signals then takes place exclusively in the central unit 30. Depending on the evaluation of the measurement signals, for example, the detection of an object close to the vehicle 35, corresponding information can then be output to a driver of the vehicle 35 via an output device 34, for example, a display or an acoustic output.

[0048] It should be noted that in the examples of implementation of the Fig. 2 and Fig. 3 a transmission of the measuring signals to the respective central unit 20 or 30 can also take place via individual lines instead of via a bus in other embodiments.

[0049] In Fig. 4 shows a flow chart to illustrate a method according to the invention, which is particularly suitable for operating the sensor systems of the Fig. 2 and Fig. 3, but can also be used independently in other sensor systems.

[0050] In step 40, measurement signals are acquired by multiple sensors. In step 41, the measurement signals are sent to a central unit, for example, via a bus or individual lines, whereby the measurement signals can be conditioned for this purpose. The measurement signals are then evaluated in step 42 exclusively in the central unit. Depending on the evaluation, information can then be output to a driver of the vehicle in step 43, for example. In other exemplary embodiments, in addition to or as an alternative to the output of information, the driving behavior of the vehicle can also be influenced, for example, through automatic steering in the case of a parking aid.

[0051] The above embodiments are to be understood as examples only, and the invention may also be implemented differently than shown.

Claims

[1] Sensor system for a vehicle (35), comprising: a variety of sensors (23-26; 31A-31D, 32A-32D), and a central unit (20; 30) coupled to the plurality of sensors (23-26; 31A-31D, 32A-32D), wherein the sensor system is designed such that an evaluation of measurement signals from the plurality of sensors (23-26; 31A-31D, 32A-32D) takes place exclusively in the central unit (20; 30), wherein the sensors (23-26; 31A-31D, 32A-32D) comprise a signal conditioning unit for adapting the measurement signals for transmission to the central unit (20; 30), and the signal conditioning unit comprises a user-specific integrated circuit (28) [2] Sensor system according to claim 1, wherein the central unit (20; 30) comprises a digital signal processor (22) for carrying out the evaluation. [3] Sensor system according to claim 1 or 2, characterized bythat the plurality of sensors (23-26; 31A-31D, 32A-32D) are coupled to the central unit (20; 30) via a bus system (214, 215; 33). [4] Sensor system according to one of the preceding claims, characterized by that the signal conditioning unit (28) comprises an analog-digital converter (29), a filter (212) and / or a mixer (213). [5] Sensor system according to one of claims 1 to 4, characterized by that the sensors (23-26; 31A-31D, 32A-32D) comprise distance sensors. [6] Sensor system according to claim 5, wherein the central unit (20; 30) is designed to determine a transit time based on the measurement signals of the plurality of sensors (23-26; 31A-31D, 32A-32D). [7] Vehicle (35) comprising a sensor system according to one of claims 1 to 6. [8] A method for operating a sensor system according to any one of claims 1 to 6, comprising: Acquiring measurement signals in the plurality of sensors (23-26; 31A-31D, 32A-32D), sending the measurement signals to the central unit (20; 30) and Evaluation of the measurement signals exclusively in the central unit (20;30).

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