SENSOR SYSTEM

Abstract

Sensor system (1) attached to a vehicle, comprising: a first sensor (2) designed to receive information in a first area (LA) outside the vehicle; a second sensor (3) designed to receive information in a second area (CA) that partially overlaps with the first area (LA) outside the vehicle; and a controller (4) configured to change the information acquisition rate of the first sensor (2) and the information acquisition rate of the second sensor (3), characterized in that The controller (4) increases the information acquisition rate of the other sensor so that it is higher than the predetermined value when the information acquisition rate of the first sensor (2) and the second sensor (3) falls below a predetermined value, wherein, if the other sensor is a LiDAR sensor, the information acquisition rate is increased by increasing the number of light sources emitting detection light or by increasing a scan frequency of detection light, or, if the other sensor is a camera, wherein the information acquisition rate is increased by increasing a frame rate.

Description

TECHNICAL AREA

[0001] The present disclosure relates to a sensor system attached to a vehicle. BACKGROUND

[0002] To implement a driver assistance system for a vehicle, it is necessary to attach a sensor to the vehicle body to detect information from outside the vehicle. Examples of such sensors include a LiDAR (light detection and ranging) sensor or a camera (see, for example, Japanese patent application no. 2010-185769). As the driver assistance system for a vehicle is further developed, the amount of information received per unit (information acquisition rate) tends to increase. With an increased information acquisition rate, the sensor's energy consumption cannot be ignored.

[0003] DE 10 2014 009 869 A1 discloses features that fall under the preamble of claim 1. US 2017 / 0 200 273 A1 is further prior art. PRESENTATION OF THE INVENTION

[0004] The present disclosure serves to keep a low drop in the information intake rate while keeping a low caloric value of the sensor system attached to a vehicle.

[0005] The invention is defined by claim 1.

[0006] One aspect of achieving the goal is a sensor system mounted on a vehicle, comprising: a first sensor designed to receive information in a first area outside the vehicle; a second sensor designed to receive information in a second area that partially overlaps the first area outside the vehicle; and a controller designed to change the information reception rate of the first sensor and the information reception rate of the second sensor, wherein, if the information reception rate of the first sensor and / or the second sensor falls below a predetermined value, the controller increases the information reception rate of the other sensor so that it is higher than the predetermined value.

[0007] One reason why the information acquisition rate of one of the sensor units might fall below a predetermined value is that a protective function is effectively keeping the sensor unit's caloric value low, or that an irregularity is occurring in the sensor's operation. In this case, the decrease in detection information acquisition capability occurs across both sensor units, particularly in an overlapping area where the first and second areas overlap. However, it is possible to compensate for the decrease in the information processing rate of one sensor and keep the decrease in information acquisition capability in the overlapping area low by increasing the information acquisition rate of the other sensor unit.Therefore, it is possible to keep the decrease in information absorption capacity low while keeping the caloric value of the sensor system attached to the vehicle low.

[0008] If the other sensor is a LiDAR sensor unit, the information acquisition rate can be increased by increasing the number of light sources emitting detection light or by increasing the scan frequency of the detection light.

[0009] If the other sensor is a camera, the information acquisition rate can be increased by increasing the frame rate.

[0010] The first or second sensor can be a LiDAR sensor or the camera.

[0011] In this specification, the "sensor unit" refers to a component part that has a required information detection function and is capable of being sold as a single unit.

[0012] In this specification, "driving assistance" refers to a control process that at least partially performs driving operations (steering, acceleration, and braking), monitors the operating environment, and ensures safe driving operations. This means that driving assistance encompasses everything from partial driving assistance, such as a collision damage mitigation braking function and a lane keeping assist function, to fully automated driving operation.

[0013] The preceding summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent with reference to the drawings and the following detailed description. SHORT FIGURE DESCRIPTION Fig. Figure 1 is a view that represents a functional configuration of a sensor system according to one embodiment. Fig. 2 is a view depicting a vehicle in which the sensor system of Fig. 1 is appropriate. Fig. 3 is a view that shows the operating sequence of the sensor system of Fig. 1 represents. DETAILED DESCRIPTION

[0014] The following detailed description refers to the accompanying drawings, which form part thereof. The illustrative embodiments described in the detailed description, the drawings, and the claims are not intended to be limiting. Other embodiments may be used, and other modifications may be made, without deviating from the basic concept or scope of the subject matter presented here.

[0015] One embodiment is described in detail below with reference to the accompanying drawings. The scale in the drawings used in the following description is appropriately adjusted to ensure that the size of each element is clearly recognizable.

[0016] Fig. Figure 1 is a view that illustrates a functional configuration of a sensor system 1 according to one embodiment. The sensor system 1 is mounted on a vehicle.

[0017] The sensor system 1 includes a LiDAR sensor unit 2. The LiDAR sensor unit 2 has a configuration for emitting invisible light and a configuration for detecting reflected light resulting from the reflection of the invisible light by at least one object located outside the vehicle. The LiDAR sensor unit 2 can have a scanning mechanism that changes the emission direction (i.e., the detection direction) and scans the invisible light as necessary. For example, infrared light with a wavelength of 905 nm can be used as the invisible light.

[0018] The LiDAR sensor unit 2 can record the distance to the object related to the reflected light, for example, based on the time elapsed from the moment the invisible light is emitted in a specific direction until the reflected light is detected. Furthermore, by accumulating such distance data in conjunction with the detection position, information about the object's shape related to the reflected light can be recorded. Additionally, or alternatively, information about properties such as the object's material related to the reflected light can be recorded based on the difference between the wavelengths of the emitted and reflected light.

[0019] The sensor system 1 includes a camera unit 3. The camera unit 3 is a device for capturing an image as information from outside the vehicle. The image can be a still or moving scene. The camera unit 3 can be a camera sensitive to visible light or a camera sensitive to infrared light.

[0020] The LiDAR sensor unit 2 and the camera unit 3 can be housed in a common casing, thus forming a single sensor module, and they can be installed in a suitable location in the vehicle (e.g., a left front corner position LF of the in Fig. 2 of the vehicle shown). Alternatively, the LiDAR sensor unit 2 and the camera unit 3 can form part of two independent sensor modules. The two sensor modules can be mounted in the vehicle at two separate locations (e.g., the left front corner position LF and a right front position RF, or the left front corner position LF and a left rear corner position LB of the vehicle shown). Fig. 2 vehicles shown).

[0021] As in Fig. As shown in Figure 1, a detectable area LA of the LiDAR sensor unit 2 and a detectable area CA of the camera unit 3 can partially overlap (overlapped area OA). The LiDAR sensor unit 2 is an example of the first sensor. The camera unit 3 is an example of the second sensor. The detectable area LA of the LiDAR sensor unit 2 is an example of the first area. The detectable area CA of the camera unit 3 is an example of the second area.

[0022] The LiDAR sensor unit 2 acquires information in the detectable area LA at a predefined information acquisition rate and outputs a detection signal LS1 corresponding to the information. The camera unit 3 acquires information in the detectable area CA at a predefined information acquisition rate and outputs a detection signal CS1 corresponding to the information. In this specification, the "information acquisition rate" refers to the amount of information acquired per unit of time.

[0023] The sensor system 1 has a controller 4. The controller 4 has an input interface 41, a processor 42, an output interface 43, and a communication bus 44. The input interface 41, the processor 42, and the output interface 43 are designed to exchange signals and data via the communication bus 44.

[0024] The detection signal LS1 output by the LiDAR sensor unit 2 and the detection signal CS1 output by the camera unit 3 are entered into the input interface 41.

[0025] The processor 42 is designed to receive the detection signals LS1 and CS1, which are input to the input interface 41, and to execute a predefined information process. The expression "receive a detection signal" refers to putting the detection signal input to the input interface 41 into a state in which a predefined information process is possible via a suitable line configuration.

[0026] The processor 42 is designed to transmit a control signal LS2 to the LiDAR sensor unit 2 via the output interface 43. The control signal LS2 is a signal for controlling the operation of the LiDAR sensor unit 2 and has the function of controlling at least the information acquisition rate of the LiDAR sensor unit 2.

[0027] Similarly, the processor 42 is configured to transmit a control signal CS2 to the camera unit 3 via the output interface 43. The control signal CS2 is a signal for controlling the operation of the camera unit 3 and has the function of controlling at least the information acquisition rate of the camera unit 3.

[0028] This means that the controller 4 is able to change the information acquisition rate of the LiDAR sensor unit 2 and the information acquisition rate of the camera unit 3.

[0029] The LiDAR sensor unit 2 can have a protective function to prevent thermal failure by autonomously reducing the information acquisition rate when the operating temperature exceeds a predefined value. For example, the LiDAR sensor unit 2 can have a configuration for monitoring the detectable area LA with multiple detection light beams emitted by multiple light sources, and a configuration for detecting information by scanning the detectable area LA with at least one detection light emitted by at least one light source. In the first case, the information acquisition rate is reduced by decreasing the number of light sources emitting a detection light beam. In the latter case, the information acquisition rate is reduced by lowering the scan frequency of the detection light beam.Since this protective function is itself well known, detailed descriptions of its features are omitted.

[0030] Camera unit 3 can have a protective function to prevent thermal failure by autonomously reducing the information acquisition rate when the operating temperature exceeds a predefined value. For example, the information acquisition rate of camera unit 3 is reduced by lowering a frame rate corresponding to the number of images captured per unit of time within the detectable area CA. Since this protective function is well-known, detailed descriptions of its implementation are omitted.

[0031] In the sensor system 1 configured as described above, the processor 42 of the controller 4 is designed such that it is able to Fig. to execute the 3 processes shown.

[0032] First, the processor 42 determines the information acquisition rate of the LiDAR sensor unit 2 based on the amount of data contained in the detection signal LS1 input into the input interface 41 (STEP 1).

[0033] The processor 42 then determines the information acquisition rate of the camera unit 3 based on the amount of data contained in the detection signal CS1 input into the input interface 41 (STEP 2).

[0034] The order of STEP 1 and STEP 2 can be reversed, or STEP 1 and STEP 2 can be performed simultaneously.

[0035] The processor 42 then determines whether the information acquisition rate of the LiDAR sensor unit 2 and / or the information acquisition rate of the camera unit 3, which are fixed, is less than a predetermined value (STEP 3).

[0036] If it is determined that the information intake rate of one of the sensor units is lower than the specified value (Y in STEP 3), the processor 42 performs a process that increases the information intake rate of the other sensor unit (STEP 4).

[0037] For example, if the information acquisition rate of the LiDAR sensor unit 2, as determined in STEP 1, is lower than the specified value, the processor 42 generates the control signal CS2 to increase the information acquisition rate of the camera unit 3, as determined in STEP 2, and transmits the control signal CS2 to the camera unit 3 via the output interface 43. In particular, an operation that increases the frame rate of the camera unit 3 is carried out by the control signal CS2.

[0038] One possible reason for the information acquisition rate of LiDAR sensor unit 2, as specified in STEP 1, being lower than the predetermined value is that the protective function for keeping the caloric value of LiDAR sensor unit 2 low is effective, or that an irregularity occurs in the operation of LiDAR sensor unit 2. In this case, a decrease in the information acquisition capability of the detection by both sensor units occurs, particularly in the overlapping area OA, where the detectable area LA of LiDAR sensor unit 2 and the detectable area CA of camera unit 3 overlap. However, it is possible to compensate for the decrease in the information processing rate of LiDAR sensor unit 2 and to keep the decrease in information acquisition capability in the overlapping area OA low by increasing the information acquisition rate of camera unit 3.

[0039] Similarly, if the information acquisition rate of the camera unit 3, as determined in STEP 2, is lower than the specified value, the processor 42 generates the control signal LS2 to increase the information acquisition rate of the LiDAR sensor unit 2, as determined in STEP 1, and transmits the control signal LS2 to the LiDAR sensor unit 2 via the output interface 43. Specifically, the process that increases the number of light sources emitting the detection light beams and / or the process that increases the scan frequency of the detection light beam is carried out according to the control signal LS2.

[0040] One possible reason for the lower information acquisition rate of camera unit 3, as specified in STEP 2, is that the protective function for keeping the caloric value of camera unit 3 low is effective, or that an irregularity occurs during the operation of camera unit 3. In this case, the information acquisition capability of both sensor units decreases, particularly in the overlapping area OA, where the detectable area LA of LiDAR sensor unit 2 and the detectable area CA of camera unit 3 overlap. However, it is possible to compensate for the decrease in the information processing rate of camera unit 3 and keep the decrease in information acquisition capability in the overlapping area OA low by increasing the information acquisition rate of LiDAR sensor unit 2.

[0041] Therefore, it is possible to keep the decrease in information absorption capacity low while keeping the caloric value of the sensor system 1 attached to the vehicle low.

[0042] If it is determined that the information acquisition rate of one of the sensor units is equal to or greater than a predetermined value (N in STEP 3), the processor 42 terminates the process.

[0043] The function of processor 42, as described, can be implemented by a general-purpose microprocessor working in conjunction with memory. Examples of the general-purpose microprocessor include a CPU, an MPU, and a GPU. The general-purpose microprocessor can have multiple processing cores. Examples of memory include a ROM and a RAM. A program executing a process described later can be stored in a ROM. This program can include artificial intelligence. Examples of artificial intelligence programs include a deep learning-based neural network. The general-purpose microprocessor can access at least some of the programs stored in the ROM, execute them in RAM, and perform the above process in conjunction with the RAM.Alternatively, the function of the processor 42 described above can be implemented by a dedicated integrated circuit such as a microcontroller, an FPGA and an ASIC.

[0044] The control unit can be located in a selectable position within the vehicle. For example, the control unit 4 can be a main ECU responsible for a central control process in the vehicle, or a sub-ECU inserted between the main ECU and each sensor unit.

[0045] The LiDAR sensor unit in the above embodiment, as an example of the first sensor, can be replaced by a camera unit or a millimeter wave sensor unit.

[0046] The millimeter wave sensor can have a configuration for transmitting a millimeter wave and a configuration for receiving a wave reflected as a result of the millimeter wave being reflected by an object located outside the vehicle. Examples of millimeter wave frequencies include 24 GHz, 26 GHz, 76 GHz, and 79 GHz. The millimeter wave sensor can detect the distance to the object relative to the reflected light, for example, based on the time from when the millimeter wave is transmitted in a specific direction until the reflected light is received. Furthermore, information about the object's movement relative to the reflected wave can be acquired by accumulating such distance data together with the detection position.

[0047] The camera unit, as an example of the second sensor in the above embodiment, can be replaced with a LiDAR sensor unit or a millimeter wave sensor unit.

[0048] In the embodiment described above, the LiDAR sensor unit 2 has a protective function for autonomously maintaining a low temperature. However, the LiDAR sensor unit 2 can be configured to output an irregularity signal if the operating temperature exceeds a predetermined value. In this case, the irregularity signal is input to the input interface 41 of the controller 4. In response to the input of the irregularity signal, the processor 42 generates the control signal LS2 to reduce the information acquisition rate of the LiDAR sensor unit 2 and transmits the control signal LS2 to the LiDAR sensor unit 2 via the output interface 43.

[0049] In the embodiment described above, the camera unit 3 has a protective function for autonomously maintaining a low temperature. However, the camera unit 3 can be configured to output an irregularity signal if the operating temperature exceeds a predetermined value. In this case, the irregularity signal is input to the input interface 41 of the controller 4. In response to the input of the irregularity signal, the processor 42 generates the control signal CS2 to reduce the information acquisition rate of the camera unit 3 and transmits the control signal CS2 to the camera unit 3 via the output interface 43.

Claims

[1] Sensor system (1) attached to a vehicle, comprising: a first sensor (2) designed to receive information in a first area (LA) outside the vehicle; a second sensor (3) designed to receive information in a second area (CA) that partially overlaps with the first area (LA) outside the vehicle; and a controller (4) designed to change the information acquisition rate of the first sensor (2) and the information acquisition rate of the second sensor (3), characterized by , that The controller (4) increases the information acquisition rate of the other sensor so that it is higher than the predetermined value when the information acquisition rate of the first sensor (2) and the second sensor (3) falls below a predetermined value, wherein, if the other sensor is a LiDAR sensor, the information acquisition rate is increased by increasing the number of light sources emitting detection light or by increasing a scan frequency of detection light, or, if the other sensor is a camera, wherein the information acquisition rate is increased by increasing a frame rate. [2] Sensor system according to claim 1, wherein one of the first sensor and the second sensor is a LiDAR sensor or a camera. [3] Sensor system according to claim 1, wherein one of the first sensor (2) and of the second sensor (3) is a LiDAR sensor or a camera.

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