Motor vehicle with automatic headlight control

Abstract

Motor vehicle with automatic headlight control, comprising a light sensor (LS) for detecting ambient brightness around the motor vehicle (KF) and a control unit (FL, AE) configured to automatically switch on a headlight of the motor vehicle (KF) when the detected ambient brightness meets a brightness criterion indicating a dark environment, wherein the control unit (FL, AE) is further configured to access data from a navigation system (NS) of the motor vehicle (KF) to determine, based on a digital map and a determined position of the motor vehicle (KF), when the motor vehicle (KF) is about to enter a dark area, and wherein, when the motor vehicle (KF) enters the dark area with automatic headlight control activated, the control unit (FL, AE) triggers the automatic switching on of the headlight of the motor vehicle (KF).characterized in that the motor vehicle (MV) is configured to receive a brightness criterion from a backend system (BS) and to use it in the motor vehicle as a brightness criterion for the ambient brightness detected by the light sensor (LS).

Description

The invention relates to a motor vehicle with automatic headlight control. Motor vehicles with automatic headlight control are known from the prior art, which automatically switches the low beam and the rear light on or off depending on the ambient light conditions without driver intervention. Motor vehicles with automatic headlight control usually include a light sensor that measures the light intensity in the vicinity of the vehicle, switching on the headlights if the light intensity is insufficient. Document DE 195 23 262 A1 describes a device for the automatic switching of lighting systems in motor vehicles, comprising a global sensor and a direction sensor. The global sensor detects changes in the general lighting conditions in the vehicle's surroundings, while the direction sensor detects tunnels or underpasses in the direction of travel ahead of the vehicle. The evaluation of the sensor signals from both the global and direction sensors triggers an automatic change in the switching state of the lighting system. German patent application DE 10 2007 000 144 A1 describes a front light control device for motor vehicles which, when automatic headlight control is activated, triggers the switching of the vehicle's headlights based on the readings from a speed sensor, a light sensor, a steering angle sensor, and a weather sensor. In this device, threshold values ​​for the sensor readings used to switch the headlights are learned during manual control operation without automatic headlight control. Document DE 197 58 667 B4 discloses a motor vehicle with automatic headlight control according to the preamble of claim 1. Motor vehicles with conventional automatic headlights often have the problem that the automatic headlight system reacts too slowly, or switches the headlights on too late or too early, or switches back and forth too frequently between the on and off states of the headlights. The object of the invention is to create a motor vehicle with an automatic headlight control system in which the times of the automatic switching of the headlights are better adapted to the ambient conditions. This problem is solved by the motor vehicle according to claim 1. Further developments of the invention are defined in the dependent claims. The motor vehicle according to the invention comprises a light sensor for detecting ambient brightness around the vehicle. The term "ambient brightness" is to be understood broadly and represents a measure of the brightness in the vicinity of the vehicle. The ambient brightness is based on sensor values ​​from one or more sensor elements of the light sensor, which measure the light intensity in the vicinity of the vehicle. For example, the ambient brightness can be the light intensity of a single sensor element or, optionally, an intensity value determined from several sensor elements, e.g., by arithmetic averaging. The motor vehicle further comprises a control unit configured such that, when the automatic headlight function is activated, it triggers the automatic switching on of a (previously switched off) headlight of the vehicle if the detected ambient brightness meets a brightness criterion indicating a dark environment.The brightness criterion can be appropriately predefined. In particular, the brightness criterion is met when the ambient brightness or a corresponding luminous intensity value is below a predefined threshold. The control unit of the motor vehicle according to the invention is further designed to access data from the vehicle's navigation system in order to determine, based on a digital map and the vehicle's determined position, when the vehicle is about to enter a dark area. The determined position is calculated within the vehicle. For this purpose, satellite-based positioning and / or network-based positioning (WLAN, WiFi, mobile network, etc.) can be used, for example. Alternatively or additionally, vehicle dynamics data can also be used for position determination. This data, in combination with the digital map, is used to predict the most probable position from the last known position in areas where there is no satellite / network reception (e.g., tunnel exits).When a vehicle enters a dark area with automatic headlights activated, the control unit triggers the automatic switching on of the (previously switched-off) headlights. In other words, based on the determination that the vehicle is about to enter a dark area, the automatic switching on of the headlights is initiated upon the actual entry of the vehicle. The term "entering" the dark area is to be interpreted broadly and can include not only the moment the vehicle actually enters the dark area but also times shortly before this entry. The dark area can be defined differently depending on the design of the automatic headlight system. Preferably, a dark area exists when the data from the digital map and the vehicle's position indicate that the vehicle is about to enter a tunnel. Besides a tunnel, other dark areas may also be present.A garage, and in particular a parking garage, can also constitute a dark area within the meaning of the invention. The vehicle according to the invention is further configured to receive a brightness criterion, and in particular a brightness criterion learned across multiple vehicles, from a backend system and to use it in the vehicle as a brightness criterion for the ambient brightness detected by the light sensor. Preferably, this variant of the invention is combined with the embodiment described above. In other words, brightness criteria are both transmitted to and received from the backend system. In the vehicle according to the invention, data from a navigation system is used for the first time to control an automatic headlight system. This allows for a significantly more responsive activation of the headlights in areas with built-up lanes. In vehicles with conventional automatic headlight systems, built-up lanes and especially tunnels are often detected too late. In a preferred embodiment of the vehicle according to the invention, the control unit is configured to further access sensor data from a camera-based weather sensor of the vehicle and trigger the activation of the (previously deactivated) headlights when the sensor data meets a bad weather criterion indicating adverse weather conditions. Such camera-based weather sensors and corresponding bad weather criteria are known from the prior art and are therefore not described in detail. Bad weather criteria include, in particular, snow, fog, spray, heavy rain, and the like. The additional use of a weather sensor further improves the automatic headlight control system. In a further, particularly preferred embodiment, the control unit of the motor vehicle according to the invention is designed such that, when the automatic headlight control is activated, it triggers a switch-off of the (previously switched on) headlights if at least the following two conditions are met: - the brightness criterion is not met; - the motor vehicle is not in a dark area according to the digital map and the determined position of the motor vehicle. If necessary, a further condition for switching off the headlights may be that the bad weather criterion, according to the sensor data of the weather sensor mentioned above, is not met, i.e., that no bad weather conditions exist. With the embodiment of the invention described above, a suitable plausibility check for switching off the headlights is implemented, which prevents the headlights from being switched off despite poor lighting conditions. In a further embodiment of the vehicle according to the invention, the control unit is designed such that, when the automatic headlight function is deactivated, the ambient brightness detected by the light sensor at times when the headlights are manually switched on and / or off by the driver is stored, and the brightness criterion is learned based on at least some of this stored information. This allows the vehicle user's preferences to be incorporated into the automatic headlight function. In a preferred embodiment, the learning of the brightness criterion consists of learning a corresponding threshold value for ambient brightness, below which the headlights are switched on. Specifically, the learning process involves averaging the ambient brightness values ​​detected at the respective times, with this average value corresponding to the learned threshold value. In a preferred embodiment of the above-described design, only the distinction between day and night is considered when learning the brightness criterion. This is achieved by considering only information on times of manual activation and / or deactivation when learning the brightness criterion, provided that the vehicle, according to the digital map and the determined position of the vehicle, is not in a dark area and is not entering or exiting one. When using a weather sensor, preferably only those times are considered when, in addition, no adverse weather conditions exist according to the adverse weather criterion. The learning described above can be vehicle-specific, meaning that corresponding ambient light levels at the times defined above are processed regardless of which driver is operating the vehicle. However, the above learning can also be driver-specific, in which case only information captured while the vehicle is being driven by the same driver is processed jointly. Determining which driver is currently operating the vehicle is achieved, in particular, by reading an identification transponder carried by the driver. In a further embodiment of the vehicle according to the invention, the control unit is configured such that, if the learned brightness criterion is met with the automatic headlight function deactivated and the headlights switched off, it triggers an output on an output unit in the vehicle. This output recommends that the driver switch on the headlights. Alternatively or additionally, the control unit is configured such that, if the learned brightness criterion is not met with the automatic headlight function deactivated and the headlights switched on, it triggers an output on an output unit in the vehicle, recommending that the driver switch off the headlights. In this way, the learned brightness criterion can also be used when the automatic headlight function is deactivated. In a preferred embodiment of the above-described design, the control unit is configured such that, if the driver switches the headlights on and / or off a predetermined number of times, particularly twice or more, in response to the output unit, it presets the activation of the automatic headlight function in the vehicle. This embodiment assumes that the driver is satisfied with the learned brightness criterion and therefore agrees to the preset "automatic headlight function activated." The output unit preferably represents a visual output unit in the form of a display, but may additionally or alternatively include acoustic or haptic output means. In a further embodiment of the motor vehicle according to the invention, the control unit is configured such that it triggers the transmission of the learned brightness criterion, for example via a mobile communication interface, to a backend system, wherein geoinformation concerning the geographical location of the motor vehicle is preferably also transmitted along with the learned brightness criterion. The geographical location of the motor vehicle is to be understood as covering a region in which the motor vehicle mainly operates. The geographical location can be of a different size and, for example, encompass a country or a part of a country. The variant of the invention described above makes it possible to further process the learned brightness criterion in a suitable manner in the backend system, e.g.The learning of the brightness criterion is to be continued across multiple vehicles, each of which has transmitted its brightness criteria to the backend system. Preferably, only vehicles with the same geographical location are considered in this learning process. In a further preferred embodiment, the vehicle includes a user interface through which the driver can adjust the sensitivity of the automatic headlight control, whereby a higher sensitivity alters the brightness criterion such that the control unit switches on the headlights when the ambient brightness detected by the light sensor is lower, provided the automatic headlight control is activated. This embodiment of the invention allows the driver to manually readjust the automatic headlight control. An embodiment of the invention is described in detail below with reference to the accompanying Fig. 1. This figure schematically shows the components relevant to the invention in an embodiment of a motor vehicle according to the invention. In Fig. 1, a motor vehicle, preferably a passenger car, is represented by the dashed outline KF. In other words, all components contained within the dashed outline are parts of the motor vehicle. Generally, in Fig. 1, the components shown are represented by thick solid lines, while the process steps performed by the components are represented by dashed rectangles and the text blocks contained within them. The interaction between the different process steps is indicated by corresponding arrows. The motor vehicle KF includes, in a manner known per se, a light sensor LS, which serves to determine the ambient brightness around the motor vehicle. In the embodiment described here, a sensor element for rain detection is also integrated into the light sensor. The light sensor is installed, for example, behind the rearview mirror on the windshield of the motor vehicle. Typically, such a light sensor includes a global sensor to detect daytime-related lighting conditions and a direction sensor that detects the light distribution in the direction of travel of the vehicle. These sensors determine the ambient brightness, whereby, when using multiple sensors, the ambient brightness is, for example, the average of the light intensities of the individual sensors. This average can, if necessary, weight the light intensity of the different sensors differently. The vehicle KF has an automatic headlight system which, when activated, automatically switches the vehicle's headlights (i.e., the low beams and taillights) on or off under predetermined conditions. The automatic headlight system is controlled by a lighting function logic (FL) and an analysis unit (AE), these two components forming a control unit as defined in the claims. These components are typically integrated into a single control unit and implemented using hardware and software. Conventionally, the automatic headlight system only considers the ambient brightness determined by the light sensor (LS). If this ambient brightness falls below or exceeds a certain threshold, the headlights are automatically switched on or off.In the embodiment of the invention described here, however, in addition to the light sensor LS, a camera-based weather sensor WS and data from the navigation system NS of the motor vehicle are also used to control the automatic headlight system. The weather sensor WS contains a camera, which is preferably also installed in the area of ​​the vehicle's windshield. Using suitable image processing methods, it is determined, in a manner known per se, whether adverse weather conditions such as snow, fog, spray, etc., are present. These image processing methods include, for example, optical flow analysis and / or the evaluation of a disparity map in the case of stereo cameras and / or color analysis and / or feature recognition (pattern recognition) within images and / or the observation of the size change of recognized features across multiple images, etc. The criterion for when the images captured by the camera-based weather sensor represent adverse weather conditions is determined by a suitable threshold criterion.Both the ambient brightness detected by the light sensor LS and the information from the weather sensor WS are fed into the functional logic FL. Furthermore, the FL function logic accesses the vehicle's NS navigation system. Specifically, it uses the navigation system's digital map in combination with the vehicle's current position, which is determined via satellite-based positioning, possibly in combination with network-based positioning and / or the evaluation of vehicle dynamics data. Using this information, the FL function logic calculates an "electrical horizon" that indicates which objects the vehicle is currently approaching. The FL function logic then uses the digital map, in combination with the vehicle's current position, to determine the vehicle's entry point into a tunnel or garage. Based on information from the light sensor (LS), the weather sensor (WS), and the navigation system (NS), the function logic (FL) determines a target state for the headlights, indicating whether they should be switched on or off. The data from the light sensor, the weather sensor, and the navigation system are used independently to determine the target state of "headlights on." Accordingly, the target state of the headlights is set to "headlights on" when the light sensor (LS) detects ambient brightness below a predetermined threshold, when the weather sensor (WS) indicates adverse weather conditions, or when the navigation system indicates that the vehicle is entering a tunnel or garage. After determining the target state of the headlights, which occurs at regular intervals, the current headlight state is determined in the FL function logic. This means it determines whether the headlights are switched on or off and whether the automatic headlight function is activated or deactivated. This information comes from the vehicle's headlight switch (SW). Depending on this information and the target headlight state, the headlights are controlled to switch the headlight state as required by the SW switch. In other words, the headlights are automatically switched on when the automatic headlight function is activated and the target headlight state is "headlights on," provided the headlights are currently switched off. Likewise, the headlights are automatically switched off when the automatic headlight function is activated and the target headlight state is "headlights off," provided the headlights are currently switched on. Unlike the determination of the target state "headlights on," in the embodiment shown in Fig. 1, the target state "headlights off" is determined using the combined data from the light sensor LS, the weather sensor WS, and the navigation system NS. In other words, the system only switches from the target state "headlights on" to the target state "headlights off" if, firstly, the light sensor LS detects ambient brightness above the corresponding threshold, and secondly, the weather sensor WS does not detect adverse weather conditions, and additionally, no tunnel or garage is detected for the current vehicle position via the navigation system NS data. This process validates the sensor data to prevent the headlights from being unintentionally switched off when the automatic headlight function is activated, even though the vehicle's surroundings are dark. According to the embodiment shown in Fig. 1, improved automatic headlight control is achieved because, in addition to the data from a light sensor LS, data from a weather sensor WS and a navigation system NS are also used to detect a dark environment. This information is also used in the control unit of Fig. 1 by an evaluation unit AE to learn the driver's switching behavior with regard to turning the headlights on and off and to consider this as a learned threshold for the ambient brightness detected by the light sensor LS. To learn the driver's switching behavior, an evaluation unit (AE) first records all events in which the driver manually switches the headlights on or off with the automatic headlight function deactivated. The ambient brightness detected by the light sensor (LS) at the time of each manual switch is stored. From this data, switching operations are extracted where, according to the weather sensor (WS), no adverse weather conditions were present, and where, according to the navigation system (NS), the vehicle (KF) was not driving in, nor entering or exiting a tunnel or garage. In other words, only switching operations where the driver activates the headlights due to the transition between day and night are considered.This takes into account that the primary purpose of the ambient brightness detected by the light sensor LS is to distinguish between day and night, whereas the weather sensor WS detects darkening due to bad weather conditions and the data from the navigation system NS detects darkening due to tunnels and garages. In the embodiment described here, the driver's switching behavior is learned by calculating an average value from the ambient brightness levels of the extracted switching operations. Depending on a predetermined termination criterion, this average value is classified as the learned brightness threshold. The termination criterion could, for example, be that the average has been calculated over a specific number of ambient brightness levels. The learned threshold is then stored in the function logic FL, which uses this value to determine, based on the ambient brightness levels detected by the light sensor LS, whether the headlights should be switched on or off. In other words, if the detected ambient brightness falls below or exceeds the learned threshold, the headlights are switched on or off, respectively. In the embodiment shown in Fig. 1, the learned ambient brightness threshold is further used to issue a switching recommendation to the driver of the vehicle KF via a display DI when the automatic headlight function is deactivated. In other words, when the automatic headlight function is not activated and the headlights are switched off or on, the driver is notified via the display that the headlights should be switched on or off when the ambient brightness determined by the light sensor LS is below or above the learned threshold. If the driver actually switches the headlights on several times (e.g., three times) after receiving such a switching recommendation, the activation of the automatic headlight function is preset in the embodiment described here, even if the driver has currently deactivated the automatic headlight function.This takes into account the fact that, due to the repeated execution of the shift recommendation, the driver is apparently satisfied with the learned threshold and will therefore be happy with the default setting "automatic headlights activated". Nevertheless, the driver still has the option to change this default setting via a corresponding menu or, if necessary, to deactivate the automatic headlights again. In the embodiment shown in Fig. 1, a user interface (BS) is also provided, which the driver can use to adjust the sensitivity of the automatic headlight control. In other words, the driver can influence the ambient brightness threshold used to determine the desired state. This threshold can also be changed, if necessary, when the system is learning the driver's switching behavior via the sensitivity setting. In the embodiment shown in Fig. 1, the learned ambient brightness threshold is further transmitted to a backend system BS outside the vehicle, preferably using a mobile communication interface. Along with the learned threshold, geoinformation is transmitted indicating the geographical area (e.g., which state or region within a state) in which the vehicle primarily operates. This information is used in the backend system to learn the shifting behavior of a fleet of vehicles from the same geographical region, with all these vehicles transmitting their learned threshold to the backend system, analogous to the vehicle KF in Fig. 1. This takes into account that the shifting behavior of drivers in different regions with varying durations of daylight differs.Learning the shifting behavior of the fleet can be done analogously to learning the shifting behavior of a single vehicle based on averaging the threshold values, except that the values ​​of a large number of vehicles are used for this averaging. The threshold value learned in the backend system BS can then be transferred back to the vehicle KF and used in that vehicle instead of the threshold value learned there. According to the invention, the backend system BS can also serve as a "virtual driving light sensor" for vehicles that do not have an onboard automatic driving light system. In this case, the vehicles in a corresponding fleet continuously transmit their currently detected ambient light levels to the backend system BS, which determines when a large proportion of these vehicles change their driving light state. This event can be detected via a percentage threshold, whereby the event is then recorded when the number of vehicles switching from "off" to "on" or vice versa exceeds the percentage threshold.In this case, a corresponding command is transmitted from the backend system to vehicles without automatic headlights, which are thereby instructed to switch on the headlights when the majority of vehicles change the headlight state from "off" to "on", and which are thereby instructed to switch off the headlights when the majority of vehicles change the headlight state from "on" to "off". The embodiment of the invention described above offers several advantages. In particular, the integration of data from a navigation system and a weather sensor enables improved automatic headlight control in a motor vehicle. The system can also learn the driver's personal preferences, resulting in better functionality of the automatic headlight control and thus greater road safety. Optionally, information from other vehicles stored in a backend system can also be incorporated into the automatic headlight control to improve its responsiveness. Furthermore, the activation of the automatic headlight control in the motor vehicle can be preset if it is observed that a driver repeatedly accepts corresponding switching recommendations when the automatic headlight control is deactivated. Reference symbol list KF Motor vehicle LS Light sensor WS Weather sensor NS Navigation system BS Backend system FL Light function logic AE Evaluation unit SW Light switch DI Display BS User interface

Claims

Motor vehicle with automatic headlight control, comprising a light sensor (LS) for detecting ambient brightness around the motor vehicle (KF) and a control unit (FL, AE) configured to automatically switch on a headlight of the motor vehicle (KF) when the detected ambient brightness meets a brightness criterion indicating a dark environment, wherein the control unit (FL, AE) is further configured to access data from a navigation system (NS) of the motor vehicle (KF) to determine, based on a digital map and a determined position of the motor vehicle (KF), when the motor vehicle (KF) is about to enter a dark area, and wherein, when the motor vehicle (KF) enters the dark area with automatic headlight control activated, the control unit (FL, AE) triggers the automatic switching on of the headlight of the motor vehicle (KF).characterized in that the motor vehicle (MV) is configured to receive a brightness criterion from a backend system (BS) and to use it in the motor vehicle as a brightness criterion for the ambient brightness detected by the light sensor (LS). Motor vehicle according to claim 1, characterized in that the control unit (FL, AE) is designed in such a way that it further accesses sensor data of a camera-based weather sensor (WS) of the motor vehicle (KF) and triggers an automatic switching on of the driving light of the motor vehicle (KF) when the automatic driving light system is activated, if the sensor data meet a bad weather criterion according to which bad weather conditions are present. Motor vehicle according to claim 1 or 2, characterized in that the control unit (FL, AE) is designed such that, when automatic headlight control is activated, it triggers the headlights to be switched off if at least the following two conditions are met: - the brightness criterion is not met; - the motor vehicle is not in a dark area according to the digital map and the determined position of the motor vehicle (KF). Motor vehicle according to one of the preceding claims, characterized in that the control unit (FL, AE) is designed such that, when the automatic headlight function is deactivated, the ambient brightness detected by the light sensor (LS) is stored at times when the headlights are manually switched on and / or off by the driver, and the brightness criterion is learned based on at least part of this stored information. Motor vehicle according to claim 4, characterized in that when learning the brightness criterion, only information on times of manual switching on and / or switching off is taken into account if the vehicle is not in a dark area according to the digital map and the determined position of the motor vehicle (KF) and does not enter or exit the dark area. Motor vehicle according to claim 5, characterized in that the learning is specific to the motor vehicle (MV) or specific to the respective drivers. Motor vehicle according to one of claims 4 to 6, characterized in that the control unit (FL, AE) is designed such that, in the event that the learned brightness criterion is met with the automatic headlight control deactivated and the headlights switched off, it triggers an output on an output unit (DI) in the motor vehicle which recommends to the driver that the headlights be switched on, and / or that, in the event that the learned brightness criterion is not met with the automatic headlight control deactivated and the headlights switched on, it triggers an output on an output unit (DI) in the motor vehicle which recommends to the driver that the headlights be switched off. Motor vehicle according to claim 7, characterized in that the control unit (FL, AE) is designed such that, in the event that the driver switches the headlights on and / or off a predetermined number of times in response to the output on the output unit (DI), it presets the activation of the automatic headlight system in the motor vehicle. Motor vehicle according to one of claims 4 to 8, characterized in that the control unit (FL, AE) is designed such that it triggers the transmission of the learned brightness criterion to a backend system (BS), wherein the learned brightness criterion preferably also transmits geoinformation relating to the geographical location of the motor vehicle (KF). Motor vehicle according to one of the preceding claims, characterized in that the motor vehicle (KF) comprises a user interface (BS) via which the driver can adjust the sensitivity of the automatic headlight control, wherein a higher sensitivity changes the brightness criterion in such a way that the control unit (FL, AE) switches on the headlights when the automatic headlight control is activated at a lower ambient brightness detected by the light sensor (LS).

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