Method and device for calculating a changed impact time of an object or a person on a vehicle

Abstract

Method (300) for calculating a changed impact time (105) of an object or a person (107) on a vehicle (110), wherein the method (300) comprises the step - Receiving (305) at least one time stamp signal (120) which comprises at least one time (125) of outputting a calculated impact time (400) of the object or person (107) on the vehicle (110) to a control unit of the vehicle (110) and the calculated impact time (400); characterized in that the method additionally comprises the step - determining (310) the changed impact time (105) using at least the time stamp signal (120).

Description

[0001] To predict collisions between objects or people and vehicles, vehicle sensors calculate an estimated impact time until an object or person detected by the sensor is likely to hit the vehicle. This impact time is then sent to the vehicle's airbag control unit for further processing.

[0002] The approach is based on a device or method according to the class of the independent claims. The present approach also relates to a computer program.

[0003] From the document DE 10 2008 043 234 A1 a method is known for correcting a predicted collision speed between a vehicle and an object, based on a predicted collision time and an actual crash start.

[0004] From the document DE 10 2013 212 092 A1 a method is known in which a threshold value for deciding whether to trigger a pedestrian protection measure is changed depending on an impact time or an impact time window. Disclosure of the invention

[0005] Against this background, the approach presented here presents a method for calculating a changed impact time of an object or person on a vehicle, a device using this method, and finally a corresponding computer program according to the main claims. The measures listed in the dependent claims enable advantageous refinements and improvements of the device specified in the independent claim.

[0006] The advantages that can be achieved with the approach presented here are that the method presented here compensates for runtime differences in a calculated impact time and thus can provide a more precise changed impact time for a control unit, for example an airbag control unit of a vehicle.

[0007] A method for calculating a changed impact time of an object or person on a vehicle is presented. The method comprises at least one receiving step and one determining step. In the receiving step, at least one timestamp signal is received, which includes at least one time of outputting a calculated impact time of the object or person on the vehicle to a control unit of the vehicle and the calculated impact time. In the determining step, the changed impact time is determined using at least the timestamp signal.

[0008] The time to impact (TTI) described here is an estimated time of impact that is calculated by default in a sensor in the vehicle that detects the object or person and then output to the control unit. The sensor can be, for example, an environmental sensor such as a vehicle camera, a radar device and / or an ultrasound device and / or a lidar device in the vehicle. In the following, it is assumed, for example, that the sensor is a vehicle camera that detects the object or person in recorded frames, i.e. image recordings. The time represents a time at which the calculated time of impact is sent from the sensor to the control unit.The control unit may be an airbag control unit which, for example, calculates and / or triggers the deployment of a personal protection device such as an airbag using the calculated impact time or, in this case, the modified impact time.

[0009] However, a transmission time elapses between the standard output of the impact time and its reception in the control unit, so that the calculated impact time is already outdated by the time it is received in the control unit. Using the method presented here, this elapsed transmission time is advantageously compensated for by runtime compensation.

[0010] For this purpose, it is advantageous if the method further comprises a reading step in which at least one further time stamp signal, which comprises at least one further time of a further output of the or a further calculated impact time of the object or person on the vehicle and the calculated impact time or the further calculated impact time, is received. The further time stamp signal can be a further time stamp signal following the time stamp signal. In the determining step, the changed impact time can now be determined using at least the time stamp signal and the further time stamp signal.

[0011] The method may further comprise a calculation step in which a delta time is calculated by subtracting the time from the further time or the further time from the time. A delta time can be understood here as a time difference. If the time and the further time of two consecutive impact times are subtracted from each other, the changed impact time can then be determined in the determination step using the determined difference time.

[0012] In the case of an incremental impact time, the calculated delta time can now be added to the impact time in the determination step, or subtracted from the impact time in the case of a decremental impact time, to determine the changed impact time. This allows a modified and thus more precise impact time to be provided to the control unit, compensated for by the difference between the two times.

[0013] If the method further comprises a provision step in which, using the modified impact time, a control signal for controlling or operating at least one personal protection device, such as an airbag of the vehicle, is provided, this can result in the personal protection device being able to be triggered, for example, at a more precise required time. For this purpose, the control signal can be output in the provision step, which causes a change in a triggering parameter, such as a triggering time of the personal protection device.

[0014] In the receiving step, the timestamp signal can be received from data transmitted over a standardized data bus. According to one embodiment of the approach described here, the timestamp signal can be received that was transmitted in one of a plurality of data packets of the data bus.

[0015] The method may also include a further receiving step in which at least one read-in time signal is received, which comprises at least one read-in time prevailing when the object or person is read by the vehicle's sensor. The read-in time may then be received, for example, in the receiving step together with the time stamp signal.

[0016] This method can be implemented, for example, in software or hardware or in a mixed form of software and hardware, for example in a control unit.

[0017] The approach presented here further provides a device configured to perform, control, or implement the steps of a variant of a method presented here in corresponding devices. The device can be implemented or implementable, for example, in a control unit of the vehicle, such as an airbag control unit of the vehicle. This embodiment of the approach in the form of a device also allows the problem underlying the approach to be solved quickly and efficiently.

[0018] For this purpose, the device can have at least one computing unit for processing signals or data, at least one memory unit for storing signals or data, at least one interface to a sensor or actuator for reading sensor signals from the sensor or for outputting data or control signals to the actuator, and / or at least one communication interface for reading or outputting data embedded in a communication protocol. The computing unit can be, for example, a signal processor, a microcontroller, or the like, wherein the memory unit can be a flash memory, an EPROM, or a magnetic storage unit.The communication interface can be designed to read in or output data wirelessly and / or via a wired connection, wherein a communication interface that can read in or output wired data can read this data, for example, electrically or optically from a corresponding data transmission line or output it to a corresponding data transmission line.

[0019] In this case, a device can be understood as an electrical device that processes sensor signals and outputs control and / or data signals depending on them. The device can have an interface that can be implemented in hardware and / or software. In a hardware implementation, the interfaces can, for example, be part of a so-called system ASIC, which contains a wide variety of functions of the device. However, it is also possible for the interfaces to be separate integrated circuits or to consist at least partially of discrete components. In a software implementation, the interfaces can be software modules that are present, for example, on a microcontroller alongside other software modules.

[0020] In an advantageous embodiment, the device controls a control signal. For this purpose, the device can access, for example, sensor signals such as a time stamp signal and another time stamp signal. Control is performed via actuators such as a receiving device, a detection device, and a provision device.

[0021] Also advantageous is a computer program product or computer program with program code that 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 to carry out, implement and / or control the steps of the method according to one of the embodiments described above, in particular when the program product or program is executed on a computer or a device.

[0022] Examples of the approach presented here are shown in the drawings and explained in more detail in the following description. It shows: Fig. 1 is a schematic representation of a device for calculating a changed impact time of an object or a person on a vehicle according to an embodiment; Fig. 2 shows a schematic representation of a device for calculating a changed impact time of an object or a person on a vehicle according to an embodiment; Fig. 3 is a flowchart of a method for calculating a changed impact time of an object or a person on a vehicle according to an embodiment; and Fig. 4 a diagram for schematically illustrating an evaluation of a changed impact time in an airbag algorithm according to an embodiment.

[0023] In the following description of advantageous embodiments of the present approach, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, whereby a repeated description of these elements is omitted.

[0024] Fig. 1 shows a schematic representation of a device 100 for calculating a changed impact time 105 of an object or a person 107 on a vehicle 110 according to an embodiment.

[0025] According to this exemplary embodiment, the device 100 presented here calculates the changed impact time 105 of the person 107 on the vehicle 110. To this end, the device 100 receives a timestamp signal 120, which includes at least a time 125 for outputting a calculated impact time of the person 107 on the vehicle 110 to a control unit of the vehicle 110 and the calculated impact time. The device 100 subsequently determines the changed impact time 105 using at least the timestamp signal 120.

[0026] According to this embodiment, the device 100 is arranged in the vehicle 110. The time stamp signal 120 is provided by a sensor 130 of the vehicle 110, which is designed as a vehicle camera. The impact time is calculated by default by the sensor 130 for each recorded frame 135 (ie, data packet).

[0027] In the following, details of the presented device 100 are explained in more detail: Sensors installed in a vehicle bumper are used to detect pedestrian collisions. Sensor systems based on two or more acceleration sensors are widely used for this purpose. So-called pressure tube sensors (PTS) have also become available recently. Many vehicles today use additional acceleration-based sensors (upfront sensors, UFS) for frontal crash detection. In addition, acceleration sensors in the airbag control unit itself are used for frontal crash detection. Either pressure or acceleration sensors are used to detect side crashes. The acceleration sensors are located on a B-, C-, or D-pillar of the vehicle. The pressure sensors, in turn, are located in a vehicle door.

[0028] In both acceleration- and pressure-based systems, an impact of an object or person in a relevant area of ​​the vehicle leads to a signal increase within the detecting sensors. The amplitude of the detected signals depends, among other things, on the mass and speed of the impacting object or person. The signals emitted by the sensors are further processed by algorithms within the airbag control unit. If the algorithm detects that a crash or pedestrian impact has occurred, active or activatable restraint devices, such as an airbag, are activated in the vehicle depending on this triggering decision in order to cushion the impact of the pedestrian on the front of the vehicle or to protect vehicle occupants in the event of a crash.

[0029] To perform the necessary classification within the algorithm, the processed signals, e.g., raw signals, window integrals, integrals, derivatives, etc., are compared against thresholds. If one or more relevant signals exceed their thresholds, the corresponding restraint devices in the vehicle are triggered.

[0030] In practice, however, it can happen that, despite highly developed algorithms, certain non-triggering objects are classified as triggering objects by the algorithm, resulting in the active restraint systems firing incorrectly. In this case, the signal thresholds in the algorithm are exceeded, for example, because the impact object has a similar mass and / or stiffness to a pedestrian. To counteract such problems, there are already developments in practice that detect a pedestrian or frontal crash as such, for example with the help of camera- or radar-based systems and / or ultrasound devices and / or laser devices, and then initiate automatic emergency braking of the vehicle before the object or person comes into contact with the vehicle or a crash occurs, in order to minimize damage to the person or the vehicle.However, even here, it may happen that the braking distance is insufficient to bring the vehicle to a standstill before the person or object comes into contact with the vehicle's bumper. Therefore, it is absolutely essential that a pedestrian protection algorithm or the frontal crash algorithm works reliably even in these cases.

[0031] Recent efforts also aim to use sensors already installed in the vehicle, such as environmental sensors (radar, camera, ultrasound, etc.), to classify objects located in front of a vehicle, e.g., as pedestrians or non-pedestrian objects. Furthermore, the environmental sensors provide an estimated time-to-impact (TTI) until the detected object or pedestrian is expected to impact the vehicle.

[0032] Using these parameters, algorithm thresholds can already be set sensitively or robustly, depending on whether a pedestrian (sensitive) or a non-pedestrian object (more robust) or a vehicle crash (tbd) was detected by the environmental sensors. This occurs within a defined time window.

[0033] One task of the device 100 presented here is to make an impact time evaluation in the airbag algorithm, e.g., a pedestrian algorithm, front crash algorithm, side crash algorithm, etc., more precise by calculating the changed impact time 105. For this purpose, according to this exemplary embodiment, the recorded frame 135 of the sensor 130 installed in the vehicle 110 is provided with a time stamp in the form of the time 125; here, the frame 135 represents an image recorded by the sensor 130 embodied as a vehicle camera. According to an alternative exemplary embodiment, the sensor 130 is not embodied as the vehicle camera, but as another environmental sensor, for example, a radar device, an ultrasound device, or a lidar device, which reads in and provides a corresponding frame. The impact time is then calculated in the sensor 130.In the next step, the calculated impact time together with other calculated variables of the sensor 130, e.g., an object class, is sent via CAN or Flexray, among others, to the device 100, which may be part of an airbag control unit of the vehicle 110, and received there for further processing within the algorithm.

[0034] By the time the impact time is received by the airbag control unit's evaluation algorithm, a certain amount of time has already passed. This means that the impact time received by the airbag control unit is already out of date. To compensate for this time difference between frame 135 and the reception of the impact time in the airbag control unit, device 100 comes into play: In a first step, the recorded frame 135 of sensor 130 has already been provided with the time stamp. Unlike known devices, the device 100 presented here receives the time 125 of the time stamp in the form of the time stamp signal 120 together with the impact time calculated from this frame 135. In a second step, device 100 calculates the changed impact time 105 using the time stamp signal 120. This process is described in Fig. 2 describe in more detail.

[0035] Fig. Figure 2 shows a schematic representation of a device 100 for calculating a changed impact time 105 of an object or a person on a vehicle according to an embodiment. This can be the time determined based on Fig. 1 described device 100.

[0036] According to this exemplary embodiment, the device 100 comprises a receiving device 200, a determining device 205, and optionally a providing device 210. The receiving device 200 receives the time stamp signal 120 and, according to this exemplary embodiment, optionally a further time stamp signal 215, which comprises at least one further time 220 of a further output of the or a further calculated time of impact of the person or object on the vehicle and the calculated time of impact or the further calculated time of impact.

[0037] The determination device now determines the changed impact time 105 using the time stamp signal 120 and, according to this exemplary embodiment, also using the further time stamp signal 215. To this end, the determination device 205 calculates a delta time according to this exemplary embodiment by calculating a difference between the time 125 and the further time 220. The calculated delta time is then subtracted from the impact time according to this exemplary embodiment in order to determine the changed impact time 105, since the impact time is counted down according to this exemplary embodiment. In the case of an incrementing impact time, the delta time is added to the impact time according to an alternative exemplary embodiment in order to determine the changed impact time 105.

[0038] According to this exemplary embodiment, the provision device 210 provides a control signal 230 for the airbag control unit of the vehicle using the modified impact time 105. The control signal 230 is configured to operate at least one passenger protection device of the vehicle. According to this exemplary embodiment, the control signal 230 is configured to effect a change in at least one triggering parameter of the passenger protection device.

[0039] In the following, details of the presented device 100 are explained in more detail: The device 100 presented here calculates the time that has elapsed between the recording of the frames and the reception of the impact times in the airbag control unit algorithm by subtracting the time stamps, i.e., the times 125, 220, of two consecutive impact times. The result of the calculation is the delta time, which can also be referred to as Δt time, which has elapsed between the recording of the frame and its reception in the airbag control unit algorithm. In a next step, the received impact times are compensated by adding the delta time to the received impact time for an incrementing impact time or subtracting it from the received impact time for a decrementing impact time. In this way, any runtime difference between the recording time of the frame and the processing in the airbag control unit algorithm is compensated.

[0040] By compensating for the differences in the time of impact, the algorithm can evaluate the expected time of impact between the person and the vehicle much more accurately. This allows for even more precise determination of whether the person or object detected by the vehicle matches the person or object detected by the sensor.

[0041] Fig. 3 shows a flowchart of a method 300 for calculating a changed impact time of an object or a person on a vehicle according to an embodiment. This can be a method 300 that is implemented by one of the methods based on one of the Fig. 1 to 2. The method 300 presented here can also be referred to as a method for compensating for runtime differences in the impact time calculation in a predictive airbag algorithm for more precise temporal evaluation of an impact object.

[0042] The method 300 comprises at least one receiving step 305 and one determining step 310. In receiving step 305, at least one timestamp signal is received, which includes at least a time of outputting a calculated impact time of an object or person on the vehicle to a control unit of the vehicle and the calculated impact time. In determining step 310, a changed impact time is determined using at least the timestamp signal.

[0043] Optionally, the method 300 according to this embodiment further comprises a step 315 of further receiving, a step 320 of reading in, a step 325 of calculating and a step 330 of providing.

[0044] In step 315 of further receiving, at least one read-in time signal is received, which comprises at least one read-in time prevailing when the object or person is read by a sensor of the vehicle.

[0045] In step 320 of reading in, at least one further time stamp signal is read in, which comprises at least one further time of a further output of the or a further calculated time of impact of the object or person on the vehicle and the calculated time of impact or the further calculated time of impact, wherein in step 310 of determining the changed time of impact is determined using at least the time stamp signal and the further time stamp signal.

[0046] In step 325 of calculating, a delta time is calculated by subtracting the time from the further time or the further time from the time, in particular wherein in step 310 of determining, the changed impact time is determined using the calculated delta time.

[0047] In step 310 of determining, according to this embodiment, the calculated delta time is then added to the impact time or subtracted from the impact time in order to determine the changed impact time.

[0048] In step 330 of providing, a control signal for operating at least one passenger protection device of the vehicle is provided to an airbag control unit of the vehicle using the modified impact time. According to this exemplary embodiment, in step 330 of providing, the control signal is output, which causes a change in at least one triggering parameter of the passenger protection device.

[0049] According to this embodiment, in step 305 of receiving, the time stamp signal is received from a standardized data bus, wherein the time stamp signal is received which is received in one of a plurality of data packets of the data bus.

[0050] The procedural steps presented here can be repeated and carried out in a different order than described.

[0051] Fig. 4 shows a diagram 400 for schematically illustrating an evaluation of a changed impact time 105 in an airbag algorithm according to an embodiment. This may be a diagram 400 that illustrates the evaluation of a change in the impact time 105 determined by means of the Fig. 1 to 2 described device or by means of the device described in Fig. 3 described method, represents the changed impact time 105.

[0052] Links in Fig. Figure 4 shows how multiple impact times 400 are received by the airbag control unit. An arrow indicates that a new object has been detected by the environment sensor, or that a new impact time 405 has been received. Since the impact time 400 was counted down within the algorithm before the new impact time 405 was received, a certain jump occurs when the new impact time 405 is received. A signal propagation time 408 elapses between the reception of the impact time 400 and the new impact time 405. Subsequently, the new impact time 405 is counted down again in the algorithm until another new impact time 409 is received. At this point, the Fig. 3, whereby the received new impact time 405 is time-of-flight compensated, as described in the previous figures. Only after the time-of-flight compensation of the new impact time 405 is it incremented as the changed impact time 105 within the airbag control unit until another new impact time 409 is received.

[0053] In Fig. 4 also shows a freeze region 410. This freeze region 410 is used to freeze the object or person with its impact time. The freeze region 410 is typically located (in time) just outside a blind zone of the corresponding environment sensor. The freeze region 410 is necessary to avoid losing the already detected object before it enters the blind zone of the environment sensor.

[0054] In addition, an acceptance range area 415 is shown. This acceptance range area 415 is required to determine whether the object or person detected by the environment sensor matches the object or person in terms of the impact time or can be assigned to this object or person that actually impacts the vehicle. According to this exemplary embodiment, a contact line 420, a positive acceptance range area 425 arranged above the contact line 420, and a negative acceptance range area 430 arranged below the contact line 420 are arranged in the acceptance range area 415. An algorithm reset point / algorithm active point 435 is also arranged on the contact line 420. The contact line 420 represents the time at which the contact or the beginning of the impact of the object or person on the vehicle occurs.

[0055] Using the approach presented here, it is possible to determine even more precisely when an object or person is located in the freeze range 410 or acceptance range 415 due to the modified impact time 105, which can also be referred to as a runtime-compensated impact time. This is essential because a runtime of just 40 milliseconds between an image capture and the reception of an impact time in the airbag control unit algorithm leads to the following distance misestimations at the following speeds: For example, if the vehicle is traveling at a speed of 20 km / h, this corresponds to 5.55 m / s. A distance misestimation for an impact travel time difference of 40 ms is 0.22 m.

[0056] For example, if the vehicle is traveling at a speed of 50 km / h, this corresponds to 13.9 m / s. A distance misestimation with an impact travel time difference of 40 ms is 0.55 m.

[0057] This means that due to a non-time-compensated impact time, the detected object or person may not chronologically match the object or person that hits the vehicle. As a result, thresholds in the algorithm may not be set robustly or more sensitively, because the object or person is temporally adjacent to the acceptance range 415.

[0058] By calculating the changed impact time 105 according to this approach, the received new impact time 405 is advantageously compensated by adding the calculated delta time to the received impact time 405 in the case of an incrementing impact time, or, as in the case of the decrementing impact time here, subtracting it from the received impact time 405 before further processing in the airbag algorithm takes place. In this way, the runtime difference between the frame recording time and the processing in the airbag control unit algorithm is compensated.

[0059] An important prerequisite for implementing this approach is forwarding the time points corresponding to the impact time 405 from the frames of the environment sensors to the airbag control unit. This can be implemented with reasonable effort.

[0060] If an embodiment includes an “and / or” link between a first feature and a second feature, this should be read as meaning that the embodiment according to one embodiment includes both the first feature and the second feature and according to another embodiment includes either only the first feature or only the second feature.

Claims

[1] Method (300) for calculating a changed impact time (105) of an object or a person (107) on a vehicle (110), wherein the method (300) comprises the step - receiving (305) at least one time stamp signal (120) comprising at least one time (125) of outputting a calculated impact time (400) of the object or person (107) on the vehicle (110) to a control unit of the vehicle (110) and the calculated impact time (400); characterized by that the procedure additionally includes the step - determining (310) the changed impact time (105) using at least the time stamp signal (120). [2] Method (300) according to claim 1, comprising a step (320) of reading in at least one further time stamp signal (215), which comprises at least one further time (220) of a further output of the impact time (400) or a further calculated impact time of the object or the person (107) on the vehicle (110) and the calculated impact time (400) or the further calculated impact time, wherein in the step (310) of determining the changed impact time (105) is determined using at least the time stamp signal (120) and the further time stamp signal (215). [3] Method (300) according to claim 2, comprising a step (325) of calculating a delta time by subtracting the time (125) from the further time (220) or the further time (220) from the time (125), in particular wherein in the step (310) of determining the changed impact time (105) is determined using the calculated delta time. [4] Method (300) according to claim 3, wherein in the step (310) of determining, the calculated delta time is added to the impact time (400) or subtracted from the impact time (400) in order to determine the changed impact time (105). [5] Method (300) according to one of the preceding claims, comprising a step (330) of providing, in which a control signal (230) for controlling at least one personal protection means of the vehicle (110) is provided using the changed impact time (105). [6] Method (300) according to claim 5, wherein in the step (330) of providing the control signal (230) is output, which causes a change in at least one triggering parameter of the personal protection means. [7] Method (300) according to one of the preceding claims, wherein in the receiving step (205) the time stamp signal (120) is received from data transmitted via a standardized data bus. [8] Method (300) according to claim 7, characterized by that the time stamp signal (120) is received which was transmitted in one of a plurality of data packets of the data bus. [9] Method (300) according to one of the preceding claims, comprising a step (215) of further receiving at least one read-in time signal which comprises at least one read-in time prevailing when the object or person (107) is read by a sensor (130) of the vehicle (110). [10] Device (100) which is configured to execute and / or control steps of the method (300) according to one of the preceding claims in corresponding units (200; 205; 210). [11] Computer program configured to carry out the method (300) according to any one of claims 1 to 9. [12] A machine-readable storage medium on which the computer program according to claim 11 is stored.

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