JP2015116945A - On-vehicle control device and on-vehicle control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle control device capable of performing accurate and profitable data back-up, when using a non-volatile memory requiring a comparatively long time for deletion and writing including a flash memory, for back-up application of information of a learned value related to the state upon collision or a vehicle, when vehicle collision or collision unexecution occurs; and to provide an on-vehicle control system.SOLUTION: Deletion of data back-up target is started by using as a trigger, information of existence of collision probability acquired from means for detecting probability of vehicle collision, and data are written by using determination of collision inevitability as a trigger.

Description

  The present invention relates to a vehicle-mounted control device and a vehicle-mounted control system that use nonvolatile storage devices to store information immediately before a vehicle collision or during an emergency stop before a vehicle collision as backup data.

  When a vehicle collision occurs, information on the vehicle before the collision occurs is stored in the nonvolatile storage device of the on-board electronic control unit (Electric Control Unit), so that the vehicle speed, accelerator, and brake operation before the collision can be controlled. You can know the state of the vehicle before the collision, such as the situation. This information is used for the next development in the field of automobile development, and there is hope for its use as evidence of traffic accidents by improving the reliability of the system in the future.

  Usually, in the use of information storage at the time of a vehicle collision, an airbag ECU having a gyro sensor (hereinafter referred to as a gyro) is used as a component, and data acquisition is generally performed using a gyro impact detection as a trigger. . At this time, a non-volatile storage device mounted on the airbag ECU is used as a storage destination of information before and after the collision. Among them, a flash memory having a property that is inexpensive but relatively slow to erase and write is used. There is a case. Since it is necessary to start writing immediately after detecting an impact, a method of deleting an area of a certain capacity in advance as in Patent Document 1 has been proposed.

  If the memory area of the data backup destination is erased in advance, if the power supply to the volatile storage device that holds the data to be written is cut off without writing being completed, the data to be written cannot be backed up. In some cases, the previous value written before erasing cannot be referred to.

  On the other hand, if erasing and writing are performed using the collision information from the gyro as a trigger without performing prior erasing, it may take time to erase or writing may be limited.

JP 2010-113580 A

  It is an object of the present invention to provide a nonvolatile memory that requires a relatively long time for erasing and writing including a flash memory in order to back up information on a situation at the time of a collision and a learning value related to a vehicle when a vehicle collision or an attempted collision occurs. It is an object of the present invention to provide an in-vehicle control device and an in-vehicle control system capable of accurate and useful data backup when using a memory.

  The in-vehicle control device includes a non-volatile storage device that needs to be erased before writing, an erasing unit of data stored in the non-volatile storage device, a data writing unit to the erasing surface, and the non-volatile storage device. In the vehicle-mounted control device comprising control means for executing the erasing means and the writing means, and vehicle behavior predicting means comprising data to be written to the nonvolatile storage device and capable of acquiring information relating to a vehicle collision. When the control means collates the event information A from the vehicle behavior predicting means and matches the erasure condition, the data is deleted by operating the erasing means, and the event information B generated after the event information A is The nonvolatile storage device is operated by the operation of the writing means by using the case where the control means collates and the write conditions are matched as a trigger. And to store the.

  According to the present invention, when a vehicle collision or a collision attempt occurs, a nonvolatile memory that requires a relatively long time for erasing and writing, including a flash memory, is used for backup of situation information at the time of the collision and information on learning values related to the vehicle. It is possible to provide an in-vehicle control device and an in-vehicle control system that can perform accurate and useful data backup when using a memory.

1 is a system configuration diagram of an engine ECU and a driving support device to which the present invention is applied. Operation | movement explanatory drawing of the vehicle-mounted control apparatus of this invention when a collision event generate | occur | produces. The conceptual diagram of the area | region division utilization of flash memory. Change in writable time. Erasure priority. 6 is an erasing / writing flowchart before collision in an embodiment of the present invention. The flowchart of the erasing / writing before collision when the erasing unit is subdivided.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  This embodiment is a data backup system that uses an engine ECU as an in-vehicle control device, has a function of recognizing the outside world by a camera as vehicle behavior prediction means, and can measure the distance and relative speed with the vehicle ahead. Figure 1 shows a schematic diagram of the system.

  The engine ECU 10 and the external environment recognition device 20 are provided, and both are connected by CAN (Controller Area Network) communication, and can transmit and receive event information and vehicle information to and from each other.

  The engine ECU 10 includes a flash memory 11 that is a non-volatile storage device, a CPU 12 that issues an erase / write command to the flash memory 11 depending on conditions, a RAM 13 that is a volatile storage device, and a communication unit between the external recognition device 20 The CAN driver 14 is provided. These are obtained by extracting a portion related to the present invention from the configuration of the engine ECU. The flash memory 11 may be a flash memory built in a microcomputer (hereinafter referred to as a microcomputer) mounted on the engine ECU. In this case, the engine ECU 10 can be replaced with a microcomputer mounted on the engine ECU.

  The external environment recognition device 20 includes a stereo camera 20a that continuously captures the outside of the vehicle with two cameras, a calculation unit 20c that calculates the position and relative speed of the front vehicle from the images of the stereo camera, and an engine ECU 10. A CAN driver 20b as a communication means is provided.

  The flash memory 11 stores the previous value of the vehicle learning value saved at the previous key-off. The vehicle learning value is information such as vehicle diagnosis information and a counter value for monitoring aging, and the current vehicle learning value 13a stored in the RAM 13 at the time of engine key-off is backed up and stored in the flash memory storage surface 11a. In addition to when the key is off, data is also written when there is a possibility that data cannot be written due to a vehicle collision.

  The CPU 12 determines information from the external recognition device, and sends an instruction to delete and write the block unit of the flash memory storage surface 11a to the FPU 11b.

  The RAM 13 holds the above-described vehicle learning value 13a and the current vehicle information 13b such as the engine speed and the brake / accelerator input status.

  The CAN driver 14 reads information on the vehicle collision transmitted by the external recognition device and transmits it to the CPU. When the vehicle information and vehicle information 13b when a vehicle collision attempt has occurred are fed back to the external recognition device, the CAN driver 14 performs transmission.

  In the data backup system having the above configuration, an operation when data is actually backed up to the flash memory storage surface 11a will be described.

The trigger of data erasure and writing largely depends on the form of the external recognition device, and the timing and amount of data erasure and writing, and how to set the priority order largely depend on the form of the flash memory storage surface. In the present embodiment, the external environment recognition device recognizes the vehicle ahead, calculates the distance / relative speed / relative acceleration with the host vehicle, digitizes the possibility of collision, and transmits it with the CAN driver 20b. Fig. 2 shows the operation timing of the external recognition device. When the distance to the preceding vehicle is less than or equal to X _a [m] (which changes according to the vehicle speed) that causes the possibility of a collision, and the relative speed calculated by the calculation unit 20c is a forward direction, The external environment recognition apparatus 20 performs a collision possibility determination 201 and transmits the collision possibility as a collision prediction time to the ECU 10 via the CAN driver 20b. At this time, the collision prediction time T _p [sec] is calculated by the equation (1) using the inter-vehicle distance x [m] (x <X _a ) and the relative speed V _r [m / sec].
T _p = x / V _r [sec] (1)

The CPU 12 of the engine ECU 10 starts erasing the flash memory storage area 11a because the T _p sent by CAN is safe for the rewriting required time T _c [sec] calculated by the engine ECU, as shown in equation (2). This is the case when the value is smaller than the margin value multiplied by the rate K.
T _c × K> T _p (2)

Moreover, while starting to transmit T _p from Equation (1), the relative acceleration a _p is monitored by calculating the change in relative speed with the preceding vehicle, and a _p is greater than the default acceleration a _max (changes with speed). When it becomes larger, the deletion starts regardless of the equation (2).

Further, the external world recognizing unit 20 obtains the braking distance X _b in the relative velocity V _r from a predetermined braking distance map, if satisfying equation (3), and sends a collision unavoidable determination 202 in FIG. 2 to the engine ECU.
X _b > V _r × T _p (3)

  As for the form of the flash memory storage surface, the memory area is divided into four blocks in FIG. The number of blocks may conform to the specifications of the flash memory, and may be two blocks. However, if priority is given to erasing and writing in units of blocks, it is necessary to use three or more blocks. In the block group in FIG. 3, reference numeral 101a denotes a storage destination block for vehicle information 13b (information on a collision) such as the engine speed and brake / accelerator input status. 101b and 101c are storage destination blocks for the learning value 13a of the vehicle. Among them, 101b is a block for storing data that must be written after erasure, and 101c is stored in another storage device even if it cannot be written. This is a data storage block that can use an initial value.

The engine ECU 10 that has received the predicted collision time T _p periodically performs the calculation of Expression (2). As shown in FIG. 4, there is a possibility that the value of the required writing time _Tc cannot be secured due to a sudden stop of the vehicle ahead. The target to be erased is selected according to the writable time that varies depending on the situation. In this embodiment, the deletion priority order of the blocks in FIG. 3 is determined as shown in FIG. By changing the order of erasing according to the remaining writing time, the risk when data rewriting by erasing and writing does not end normally is reduced. As for the priority of writing, referring to the table of variables with high priority created based on the unit of writing in the division for each block, writing is performed according to the table.

  FIG. 6 shows a flowchart of operations until data backup is performed in this embodiment.

  FIG. 7 shows a flowchart of the data backup operation in the case where the number of divided blocks is larger than that in the embodiment divided into the four blocks described above.

  According to the present invention, the engine ECU receives the possibility of collision of the vehicle and the expected collision time from an external device, or can easily calculate from the received data. Therefore, it is possible to erase the data area to be erased on the flash memory after the possibility of the collision and to secure time for writing data in the area to be written. As a result, data of a type that is not desired to be erased until immediately before writing can be written to the flash memory at the time of collision.

  In addition, storing the collision information in the engine ECU has the following advantages despite the fact that the driving support system is installed.

  The driving support system can also acquire vehicle speed, brake, and accelerator information through communication with the engine ECU, but doing so increases the computation load on the main CPU and is not preferable. If you write to the flash memory built into the microcomputer in the engine ECU, the dedicated processor processes it, so there is no load on the main microcomputer. Furthermore, the data held by the engine ECU that is provided to the driving support system via communication is a part of the data that is effective for analyzing the collision held by the engine ECU, and is stored in the flash memory as it is owned by the engine ECU. By doing so, you can simulate from the backup data saved later and reproduce the situation before the collision more precisely.

10 Engine ECU
11 Flash memory
12 CPU
12a Erasing means
12b Writing means
13 RAM
13a Vehicle learning value
13b Vehicle information
14 CAN driver
20 External recognition device
20a stereo camera
20b CAN driver
20c arithmetic unit
201 Judgment of possible collision
202 Collision unavoidable judgment
203 Collision event occurred
101a Vehicle information data
101b 1 learning data group
101c Learning value data 2 groups
401 Collision prediction at constant speed
402 Collision prediction during acceleration

Claims (7)

Non-volatile storage device that needs to be erased before writing, erasing means for data stored in the non-volatile storage device, data writing means for the erasing surface, erasing means for the non-volatile storage device, and In a vehicle-mounted control device comprising a control means for performing the writing means and data to be written to the non-volatile storage device, and a vehicle behavior prediction means capable of acquiring information related to a vehicle collision.
Using the event information A from the vehicle behavior prediction means as a trigger when the control means matches and matches the erasure condition, the deletion means is operated to delete the data,
Further, the event data B generated after the event information A is stored in the nonvolatile storage device by the action of the writing means, triggered by the case where the control means matches the writing condition with the control means. In-vehicle control device. A nonvolatile storage device that needs to be erased before writing, a storage data erasing unit of the nonvolatile storage device, a data writing unit to the erasing surface, the erasing unit with respect to the nonvolatile storage device, and the In a vehicle-mounted control device that includes a control unit that implements a writing unit and can communicate with a vehicle behavior prediction unit that can acquire information on a vehicle collision,
Using the event information A from the vehicle behavior prediction means as a trigger when the control means matches and matches the erasure condition, the deletion means is operated to delete the data,
Further, the vehicle information is stored in the nonvolatile storage device by the action of the writing means, triggered by the case where the control means collates the event information B generated after the event information A and matches the write condition. Control device.   3. The memory area of the non-volatile storage device according to claim 1, wherein the memory area of the nonvolatile memory device is divided into a plurality of blocks, the write target data is divided into groups of the number of divisions of the blocks, and erase or write is performed in block units according to priority. A vehicle-mounted control device characterized by performing.   In Claim 1, the on-board control device calculates grace time information that can be used for erasing and writing while starting erasing, and changing the amount of data to be erased and the amount of data to be written according to the grace time. A vehicle-mounted control device.   3. The information on the grace time that can be used for erasing and writing is received and calculated from the vehicle behavior predicting means according to claim 2, and the amount of data to be erased and the amount of data to be written are determined according to the grace time. An in-vehicle control device characterized by being changed.   6. The on-vehicle control device according to claim 4, wherein the control means determines the priority order of erasing or writing based on the grace time.   In the in-vehicle control system provided with an independent vehicle behavior prediction device as the vehicle behavior prediction means according to claim 2, if a vehicle collision does not occur, the writing is completed even in the middle of erasure and writing, A vehicle-mounted control system, wherein data relating to a vehicle stored by a vehicle-mounted control device is sent to the vehicle behavior prediction device.