Method and control unit for monitoring at least one blind spot of a vehicle

Abstract

The present invention relates to a method for monitoring at least one blind spot (108) of a vehicle (100), wherein rear sensor data (118) from at least one rear sensor (102) of the vehicle (102) detecting a rear part (114) of the blind spot (108) and side sensor data (122) from at least one side sensor (104) of the vehicle (100) detecting a front part (116) of the blind spot (108) are evaluated in order to detect target vehicles (120) in the blind spot (108), wherein a warning (124) is issued to a driver (110) of the vehicle (100) when a target vehicle (120) is detected in the blind spot (108).

Description

Field of the InventionThe invention relates to a method for monitoring at least one blind spot of a vehicle, to a corresponding control device, and to a corresponding computer program product.Prior ArtA blind spot of a vehicle may be referred to as a region of a surroundings of the vehicle that is located neither in a direct field of view of a driver of the vehicle nor in an indirect field of view of the driver. The direct field of view can be viewed by the driver, without a greater rotation of his head from the direction of travel, by direct visual connection forwards and sideways. The indirect field of view may be viewed by the driver through indirect visual communication via mirrors or cameras of the vehicle. The blind spot exists on both sides of the vehicle and extends from a rear or lateral boundary of the direct field of view to an outer or lateral boundary of the indirect field of view.A rear sensor disposed at a rear of the vehicle may detect target vehicles located behind the vehicle, approaching the vehicle from behind, or departing from the vehicle. In this case, the rear sensor can also detect rear regions of the blind spot lying within its detection range. Since the detection range of the rear sensor is limited by a field of view of the sensor and / or a body of the vehicle, the target vehicles can only become approximately up to the height of the rear or behind the vehicle. Laterally next to the vehicle, target vehicles may be only restricted or not detected. Front portions of the blind spot laterally of the vehicle are outside the detection range and cannot be detected by the rear sensor.In order to be able to output a blind spot warning or lane change warning for these front regions as well, movements of the target vehicles within the detection range of the rear sensor can be detected movements of the target vehicles and predictions can be made for the movements in the front regions of the blind spot on the basis of the detected movements and the assumption that the movements are continued.Disclosure of the InventionAgainst this background, the approach presented here presents a method for monitoring at least one blind spot of a vehicle, a corresponding control device, and a corresponding computer program product according to the independent claims. Advantageous refinements and improvements of the approach presented here are evident from the description and are described in the dependent claims.Advantages of the InventionIn the approach presented here, additional sensors are used for monitoring the blind spot. At least two sensors are used for monitoring a side of the vehicle. At least one of the sensors is oriented rearward and at least one of the sensors is oriented aside. The rearward facing sensor is referred to as a rear sensor. The sensor oriented to the side is referred to as a side sensor. The rear facing sensor senses target vehicles behind the vehicle and laterally behind the vehicle until the target vehicles exit the sensing range of the rear sensor forward. The side-facing sensor senses target vehicles adjacent to the vehicle once they are within the sensing range of the side sensor. The side sensor may also sense target vehicles travelling laterally in front of and / or laterally behind the vehicle. The detection ranges of the rear sensor and the side sensor may overlap. When monitoring blind spot on both sides of the vehicle, at least three sensors are used, with at least one of the sensors being oriented rearward and at least two sensors being oriented toward the opposite sides, respectively. A plurality of sensors can also be oriented toward the rear. Likewise, a plurality of sensors can be aligned with one side.The signals from the rear and side facing sensors are evaluated together to detect target vehicles in blind spots.The approach presented here complements the detection ranges of the differently oriented sensors and target vehicles laterally next to the vehicle can be detected in an improved manner. Predictions of movements of the target vehicles based on measurements of the one sensor may be supported by measurements of the other sensor. Changes in the movements can thus be detected and improved lane change warnings or blind spot warnings can be output.A method for monitoring at least one blind spot of a vehicle is proposed, wherein rear sensor data from at least one rear sensor of the vehicle detecting a rear subregion of the blind spot and side sensor data from at least one side sensor of the vehicle detecting a front subregion of the blind spot are evaluated in order to detect target vehicles in the blind spot, wherein a warning is output to a driver of the vehicle if a target vehicle is detected in the blind spot.Ideas regarding embodiments of the present invention can be considered, among other things, to be based on the ideas and findings described below.A blind spot may extend laterally and laterally behind a vehicle. A blind angle can extend on each side of the vehicle. Vehicles in the blind spot cannot be seen directly by a driver of the vehicle or via rear-view mirrors and side mirrors of the vehicle. When a vehicle is in blind spot, it cannot be perceived by a driver of the vehicle without substantial rotation of the head from the direction of travel or shoulder gaze. In the case of a steering movement towards the vehicle in the blind spot, the risk of an accident may arise.A rear portion of the blind spot may extend laterally behind the vehicle. A front portion may extend substantially laterally of the vehicle. The lateral sub-region can also extend laterally behind the vehicle.A rear sensor may be oriented substantially rearward. A side sensor may be substantially aligned to the side. The rear sensor may provide rear sensor data in which detected objects are represented in a detection range of the rear sensor. The side sensor may provide side sensor data in which detected objects are represented in a detection range of the side sensor.The side sensor and the rear sensor can have different measurement principles. In particular, the rear sensor can have a higher measurement accuracy than the side sensor. Based on the rear sensor data, trajectories of the target vehicles may be calculated. The trajectories can be predicted in the future. The predictions may be supported or offset by the side sensor data.The tail sensor data and the side sensor data may be merged into merged sensor data. The fused sensor data may be evaluated to identify the target vehicles in the blind spot. In particular, in the case of different measurement principles of the rear sensor and the side sensor, the rear sensor data and the side sensor data can be merged in order to obtain uniform merged sensor data. This allows target vehicles to be tracked safely over boundaries of the detection ranges.Lateral sensor data from two lateral sensors detecting the front sub-region can be evaluated. The front portion may be larger than the sensing range of a single sensor. Then, a plurality of sensors may be used for detecting the front portion. In addition, two sensors can observe a detection range from different angles, so that their sensor data can be evaluated using triangulation and thus supplementary location information about objects or vehicles within the detection range can be determined.Sensor data from side sensors with overlapping detection ranges can be evaluated. The front sub-region can be detected redundantly. The side sensors may be simple sensors. By covering the front partial region several times, a detection probability can be increased.Target vehicles in the front sub-region can be detected at least two-dimensionally. In the case of overlapping detection regions of the side sensors, direction information or position information can also be determined with the simple sensors. The side sensors can each provide distance information without directional information. A position of the side sensors on the vehicle is known. By triangulation using a base width between the side sensors, a direction to a target vehicle detected by both side sensors or a position of the target vehicle can be determined using the individual distance information.As at least one of the side sensors, an ultrasonic sensor may be used. An ultrasonic sensor may provide range information without directional information. The ultrasonic sensor may be a simple sensor. The ultrasonic sensor can be cost-effective and robust. The ultrasonic sensor may be small. The ultrasonic sensor can be easily integrated on the vehicle.The vehicle may be a motorcycle, i.e., a two-wheeled motor vehicle. On the one hand, for motor bicycles, the use of laterally oriented sensors has been unusual up to now. On the other hand, it can be particularly important for driving safety especially in the case of motor bicycles to be able to monitor the blind spot as well as possible.As the side sensor, a sensor disposed at or near a handlebar of the motorcycle may be used. The sensor can have an unobstructed detection range at or near the handlebar. "Near the handlebar" can mean here that the side sensor is arranged closer to a front wheel steered by the handlebar than to a rear wheel of the vehicle, in particular in front of the geometric center of the vehicle, preferably in a front-most quarter of the vehicle.As the second side sensor, a sensor disposed at a rear of the motorcycle may be used. The rear side sensor may be directed slightly forward. The sensor arranged on or near the steering arm can be directed slightly rearward. As a result, the detection regions can overlap greatly and two-dimensional measurements can be carried out there.A radar sensor, a lidar sensor or a camera can be used as the rear sensor. In particular, a radar sensor may provide range information and direction information. The radar sensor may have a long range. The radar sensor may have high accuracy. The radar sensor may have high robustness. Lidar sensors or cameras may also provide similar information. Measurements of the side sensor may be used to ascertain estimates of the trajectory of a target vehicle based on the measurements of the rear sensor.The method is preferably computer-implemented and can be implemented, for example, in software or hardware or in a mixed form of software and hardware, for example, in a driver assistance system.The approach presented here furthermore creates a control device, wherein the control device is designed to carry out, actuate or implement the steps of a variant of the method presented here in corresponding devices.The control device can be an electrical device having at least one arithmetic unit for processing signals or data, at least one memory unit for storing signals or data, and at least one interface and / or one communication interface for reading in or outputting data embedded in a communication protocol. The computing unit can be, for example, a signal processor, a so-called system ASIC or a microcontroller for processing sensor signals and outputting data signals depending on the sensor signals. The memory unit may be, for example, a flash memory, an EPROM, or a magnetic memory unit. The interface can be designed as a sensor interface for reading in the sensor signals from a sensor and / or as an actuator interface for outputting the data signals and / or control signals to an actuator. The communication interface can be designed to read in or output the data wirelessly and / or in a wired manner. The interfaces can also be software modules which are present, for example, on a microcontroller, in addition to other software modules.A computer program product or computer program with program code which can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and is used for carrying out, implementing and / or controlling the steps of the method according to one of the embodiments described above is also advantageous, in particular if the program product or program is executed on a computer, in a control device or a device.It is to be understood that some of the possible features and advantages of the invention are described herein with reference to various embodiments. A person skilled in the art recognizes that the features of the control unit and of the method can be combined, adapted or exchanged in a suitable manner in order to arrive at further embodiments of the invention.Brief Description of the DrawingsEmbodiments of the invention are described below with reference to the attached drawings, wherein neither the drawings nor the description should be interpreted as restricting the invention. FIGS. 1 to 3 show representations of a vehicle having a rear sensor, side sensors and a control device according to exemplary embodiments.The figures are schematic only and not to scale. Identical reference numerals designate identical or identically acting features.Embodiments of the InventionFIGS. 1 to 3 show representations of a motorcycle 100 having a rear sensor 102, side sensors 104 and a control device 106. A method for monitoring blind spots 108 of the motorcycle 100 according to an exemplary embodiment is carried out on the control device 106. The blind spots 108 extend between a direct field of view of a driver 110 of the motorcycle 100 and an indirect field of view of the driver 110 via mirrors of the motorcycle 100.The rear sensor 102 is disposed at a rear of the motorcycle 100 and oriented rearward toward a traveling direction of the motorcycle 100. The rear sensor 102 has a substantially circular sector-shaped detection region 112 which encloses rear partial regions 114 of the blind spots 108. The detection range 112 here corresponds substantially to a maximum field of view of the rear sensor of 150°. The sensing area 112 is not limited here by parts of a body of the motorcycle 100.The side sensors 104 are arranged on a handlebar of the motorcycle 100 and oriented laterally transversely to the direction of travel. One side sensor 104 is oriented to the right and left. The side sensors 104 also have substantially circular sector-shaped detection regions 112 which enclose front partial regions 116 of the blind spots 108. Also in the side sensors 104, the detection ranges 112 substantially correspond to maximum fields of view of the side sensors 104. Due to the arrangement on the steering arm, the detection areas 112 are not restricted by parts of the body or the driver 110.The rear sensor 102 provides rear sensor data 118 to the controller 106. Measurements of target vehicles 120 within the sensing range 112 of the rear sensor 102 are represented in the rear sensor data 118. The rear sensor 102 provides at least two-dimensional measured values to the target vehicles 120. For example, the rear sensor 102 provides a distance indication and a direction indication or position coordinates for the detected target vehicles 120.The side sensors 104 provide side sensor data 122 to the controller 106. Measurements of target vehicles 120 within the detection ranges 112 of the side sensors 104 are represented in the side sensor data 122. The side sensors 104 provide at least one-dimensional measured values to the target vehicles 120. For example, the side sensors 104 provide a distance indication for the detected target vehicles 120.Here, one of the side sensors 104 as the target vehicle 120 respectively detects another motorcycle 120 in the front partial region 116 of the blind spot 108 covered by its detection region 112. FIGS. 1 to 3 show different warning situations for a warning 124, i.e. a lane change warning or blind spot warning.In FIGS. 1 and 2, the other motorcycle 120 travels faster than the motorcycle 100 and was first detected by the rear sensor 102 during a rear approach. A right lane change warning 124 was output by the control device 106 to the driver 110 via a human-machine interface 126 of the motorcycle 100 when the other motorcycle 120 has entered the right rear partial region 114 of the blind spot 108. The other motorcycle 120 thus passes over the right side of the motorcycle 100. Due to the greater speed of the other motorcycle 120, it moves out of the detection range 112 of the rear sensor 102 via a lateral delimitation of the detection range 112 and can no longer be detected by the rear sensor 102.During or after leaving the sensing area 112 of the rear sensor 102, the other motorcycle 120 enters the sensing area 112 of the right side sensor 104. The right side sensor 104 sends the detection of the other motorcycle 120 in the side sensor data 122 to the controller 106.In FIG. 1, the other motorcycle 120 moves away from the motorcycle 100 to the right, thereby leaving the blind spot 108. The movement of the other motorcycle 120 away from the motorcycle 100 is detected by the side sensor 102 and mapped into the side sensor data 122. If the other motorcycle 120 has left the blind spot 108, the lane change warning 124 is ended by the control device 106.In FIG. 2, the other motorcycle 120 decelerates next to the motorcycle 100 and remains invisible to the rider 110 at a short distance from the motorcycle 100 in the blind spot 108. The side sensor 104 senses the other motorcycle 120 and maps the short distance in the side sensor data 122. Because the other motorcycle 120 remains in the blind spot 108, the lane change warning 124 is maintained by the controller 106.In FIG. 3, the other motorcycle 120 approaches the motorcycle 100 from behind outside the sensing range 112 of the rear sensor 102. Since it is not detected in this case, the control device 106 also does not emit a warning. Obliquely behind the motorcycle 100, the other motorcycle 120 travels toward the motorcycle 100 and thereby enters the front portion 116 of the blind spot 108. In this case, the other motorcycle 120 is detected by the side sensor 104. When entering blind spot 108, lane change warning 124 is triggered by the control device.In one embodiment, the motorcycle includes a front side sensor 104 and a rear side sensor 104 per side. The front side sensor 104 is arranged in the region of the steering arm. The rear side sensor 104 is disposed behind a bench seat of the motorcycle 100. Both side sensors 104 are oriented transversely to the direction of travel, the front side sensor 104 being oriented slightly rearward and the rear side sensor 104 being oriented slightly forward. As a result, the side sensors 104 have overlapping detection regions 112. Using the side sensor signals 122 from both side sensors 104 of one side, the controller 106 may determine a position of the other motorcycle 120 adjacent to the motorcycle 100 at least two-dimensionally.In one embodiment, the rear sensor 102 is a radar sensor and the side sensors 104 are ultrasonic sensors. The radar sensor has a substantially longer range than the ultrasonic sensors. The shorter range of the ultrasonic sensors is sufficient since a warning range 128 for the lane change warning 124 or blind spot warning 124 has a smaller extent than the range of the ultrasonic sensors. The controller initiates the lane change warning 124 when the target vehicle 120 is in the warning area 128.Possible embodiments of the invention are summarized again below or presented with a slightly different word selection.An extension and adjustment of blind spot monitoring with laterally mounted ultrasonic sensors is presented.Rear mounted blind spot monitoring and lane change assist (BSD / LCA) sensors (e.g., corner radars, cameras, lidars) may not fully cover the blind spot monitoring and lane change assist (BSD / LCA) warning area on a vehicle according to ISO 17387 due to the limited field of view.A predicted trajectory outside the field of view (FOV) of the sensor may not well match the actual trajectory when the target vehicle is small and has complex motion characteristics (e.g., a motorcycle that enters and exits the adjacent lane), which may result in an early warning decline (i.e., the target vehicle brakes after leaving the blind spot monitoring sensor field of view (FOV) and lane change assist (BSD / LCA)), or an extended warning (i.e., the target vehicle leaves the field of view (FOV) at a low relative speed and then accelerates).By adding lateral ultrasonic sensors to the system, the entire blind spot monitoring warning area and lane change assist (BSD / LCA) can be covered. FIG. 1 shows the field of view (FOV) of the radar, where the radar blindness gap is compensated by a single laterally mounted 90-degree ultrasonic sensor (USS) on each side. The measurements of the ultrasonic sensors can be used to optimize the existing algorithms for predicting the object trajectory in the high-performance sensors in order to eliminate the above-mentioned disadvantages.The approach presented requires four major technical features at the hardware level. A main sensor unit (i.e. rear radar, rear cameras, lidar) on the relevant vehicle is the most important high-performance and high-resolution sensor unit for detecting relevant following vehicles and for forwarding measurement data which are processed by a decision unit. Lateral ultrasonic sensors provide measurements in the lateral warning range of the vehicle for monitoring blind spot and lane change assist (BSD / LCA) that is not detected by the main sensor unit at the rear and forward the information to the decision unit. In motor bicycles, they should be mounted at an angle of 90 degrees near the front handlebar. The decision unit (i.e., the electronic processing unit (ECU) of the rear radar) determines whether the target vehicles are within the blind spot monitoring warning range and the lane change assist (BSD / LCA) defined in the ISO standard 17387, and gives a warning message to the human-machine interface (HMI). It may also process the measurement data of the lateral ultrasonic sensors to assist in predicting the trajectory of the target vehicle leaving the field of view (FOV) of the rear main sensing unit. The human-machine interface (HMI) (i.e., a head unit display, the driver helmet, a smartphone and / or warning indicators connected to the motorcycle) displays a warning to the driver of blind spot monitoring and lane change assist (BSD / LCA).For the approach presented, a technical function can also be implemented at the software level, which can be considered, however, as part of the component of the decision unit. In the decision unit, sensor fusion software may be implemented to fuse the measurements of the rear main sensing unit and the lateral ultrasonic sensors and project the trajectory information (distance, speed, acceleration, etc.) of the target vehicles in the blind spot monitoring area and lane change assist (BSD / LCA).The rear main sensor measures and recognizes objects in its field of view behind the vehicle that are in the blind spot monitoring and lane change assist (BSD / LCA) warning area, and forwards the measurement information to the decision unit.Typical examples of the most important rear sensor units are radars, lidars and cameras. Starting from a single rear-mounted radar with a 150 degree field of view (FOV), a trapezoidal blind area in the blind spot monitoring warning zone and lane change assist (BSD / LCA) may be derived. This minimum blindness zone is based on the use of a radar with an optimum field of view (FOV) of 150 degrees. The detection range of 0.5 m to 3 m in the lateral direction (dy) is also a minimum requirement of ISO 17387.The lateral ultrasonic sensors are mounted on the side of the vehicle at an angle of about 90 degrees outward to measure lateral object information in the blind spot warning area (BSD) that is not detected by the main sensor unit. This information is also passed to the decision unit.A single ultrasonic sensor can only provide range measurements of any target object in its field of view (FOV). Multiple ultrasonic sensors on the same side may provide additional information about the position of the target object using triangulation techniques.The decision unit processes the measurements of both the rear main sensor unit and the lateral ultrasonic sensors to generate projected trajectories of relevant target vehicles for blind spot monitoring and lane change assist (BSD / LCA). When a relevant target object is detected as a valid target object for blind spot monitoring and lane change assist (BSD / LCA), a warning message is sent to the human-machine interface (HMI). The sensor fusion software is implemented to optimize tracking of the target object near and outside the detection limit of the main detection unit.For example, if a target vehicle has been lost from the radar in its blind zone, ultrasonic measurements are used to verify whether the target vehicle is leaving the warning zone (e.g., lane change or acceleration). The system minimizes the cases where the warning aborts prematurely or false positive warnings are issued for a longer period of time.The human machine interface (HMI) receives the warning request from the decision unit and passes the warnings to the driver. This can be done in the form of visual displays on the display of the head unit, the helmet of the driver and / or the rear-view mirrors.The vehicle is equipped with lateral ultrasonic sensors as well as a rear sensor unit for monitoring the blind spot and for detecting the lane change assist (BSD / LCA). Blind spot monitoring and lane change warning (BSD / LCA) are thereby improved for small target vehicles (e.g., two-wheeled scooters). The blind spot monitoring warning (BSD) may be ended with appropriate timing when the rear bumper of the target vehicle is just passing the rear bumper of the vehicle and the target vehicle is immediately making a lane change. The blind spot monitoring warning (BSD) remains active when the rear bumper of the target vehicle passes the rear bumper of the vehicle and rapidly decelerates to remain in the blind spot monitoring warning range (BSD). The blind spot monitoring (BSD) alert may be triggered at an appropriate time when a target vehicle in front of the vehicle bumper switches the lane to the adjacent lane.Finally, it should be noted that terms such as "having", "comprising", etc. do not exclude other elements or steps and terms such as "a" or "an" do not exclude a plurality. Reference signs in the claims should not be regarded as limiting.

Claims

Method for monitoring at least one blind spot (108) of a vehicle (100), wherein rear sensor data (118) from at least one rear sensor (102) of the vehicle (102) detecting a rear subregion (114) of the blind spot (108) and side sensor data (122) from at least one side sensor (104) of the vehicle (100) detecting a front subregion (116) of the blind spot (108) are evaluated in order to detect target vehicles (120) in the blind spot (108), wherein a warning (124) is output to a driver (110) of the vehicle (100) if a target vehicle (120) is detected in the blind spot (108).The method of claim 1, wherein the rear sensor data (118) and the side sensor data (122) are merged into merged sensor data, wherein the merged sensor data is evaluated to detect the target vehicles (120) in the blind spot (108).Method according to one of the preceding claims, in which side sensor data (122) are evaluated by two side sensors (104) which record the front sub-region (116).Method according to Claim 3, in which side sensor data (122) are evaluated by side sensors (104) having overlapping detection regions (112), target vehicles (120) being detected at least two-dimensionally in the front subregion (116).Method according to one of the preceding claims, in which an ultrasonic sensor is used as at least one side sensor (104).Method according to one of the preceding claims, in which the vehicle (100) is a motorcycle (100) and a sensor arranged on or close to a handlebar of the motorcycle (100) is used as the side sensor (104).Method according to Claims 3 and 6, in which a sensor arranged at a rear of the motorcycle (100) is used as the second side sensor (104).Method according to one of the preceding claims, in which a radar sensor, a lidar sensor or a camera is used as the rear sensor (102).Control device (106), wherein the control device (106) is designed to execute, implement and / or actuate the method according to one of the preceding claims in corresponding devices.A computer program product configured to direct a processor, when executing the computer program product, to execute, implement and / or drive the method according to any one of claims 1 to 8.A machine readable storage medium having stored thereon the computer program product of claim 10.

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