Vehicle control device

Abstract

To enable a vehicle to immediately start in accordance with the intention of a driver even during collision-response braking control of the vehicle.SOLUTION: When it is determined that there is a possibility of an object colliding with a vehicle 1 from the rear while the vehicle 1 is stopped, collision-response braking control is executed to apply to the vehicle 1 a braking force necessary to suppress forward movement of the vehicle 1 caused by the collision of the object. During the collision-response braking control, it is determined whether a rearward acceleration induced in the vehicle by the collision of the object has occurred. When such rearward acceleration occurs during the collision-response braking control, if an accelerator pedal depression operation is performed, the collision-response braking control is continued and the accelerator pedal depression operation is regarded as not having been performed.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] When a vehicle collides with another vehicle while traveling, a post-collision braking control is performed to apply a braking force to the vehicle to decelerate it, thereby preventing a secondary collision involving another nearby vehicle. In this case, the post-collision braking control is typically released by depressing the accelerator pedal, allowing the vehicle to start moving. However, this is undesirable because the post-collision braking control is released and the vehicle starts moving even if the accelerator pedal is depressed against the driver's will due to sudden deceleration during a collision. Therefore, a vehicle control device is known that releases the post-collision braking control and allows the vehicle to start moving when the driver depresses the accelerator pedal twice to a predetermined depth, allowing the vehicle to start moving at the driver's will (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-78475 Summary of the Invention [Problem to be solved by the invention]

[0004] However, as in the above-mentioned known vehicle control device, the requirement that the driver depress the accelerator pedal twice to a predetermined depth before the vehicle can start is not only cumbersome for the driver, but also poses the problem that if the driver is configured to be unable to start the vehicle unless the accelerator pedal is depressed twice, the vehicle cannot be started immediately when the driver wishes to start the vehicle. Note that the above-mentioned known vehicle control device is intended for when the host vehicle collides with another vehicle while traveling, and is fundamentally different from the present invention, which is intended for when there is a possibility that the vehicle will be hit by an object from behind while it is stopped. [Means for solving the problem]

[0005] In order to solve such problems, according to the present invention, there is provided a vehicle driving force adjusting accelerator pedal, an acceleration sensor capable of detecting acceleration in the front-rear direction of the vehicle, a detection sensor capable of detecting an object approaching the vehicle from behind, a braking device that applies braking force to the vehicle, and a processor, The processor When it is determined based on the detection result of the detection sensor that there is a possibility that an object will collide with the vehicle from behind while the vehicle is stopped, the braking device is caused to perform collision response braking control that applies to the vehicle a braking force necessary to suppress forward movement of the vehicle due to the collision of the object, During the collision braking control, it is determined whether or not rearward acceleration caused by a collision with an object is occurring in the vehicle; During collision response braking control, if the accelerator pedal is depressed while rearward acceleration is occurring, the collision response braking control continues and the accelerator pedal is treated as not being depressed, To provide a vehicle control device which, when an accelerator pedal is depressed while no rearward acceleration is occurring during collision countermeasure braking control, cancels the collision countermeasure braking control and adjusts the driving force of the vehicle in response to the accelerator pedal depression operation. [Effects of the Invention]

[0006] Even during collision response braking control of the vehicle, the vehicle can be started immediately in response to the driver's intention. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing the functional configuration of a vehicle. [Figure 2] FIG. 2 is a time chart showing the changes in relevant parameters when an object collides with a stopped vehicle from behind. [Figure 3] FIG. 3 is a flowchart for executing braking control. [Figure 4] FIG. 4 is a flowchart for executing the control execution continuation flag process shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] FIG. 1 shows the functional configuration of vehicle 1. Vehicle 1 can be driven either manually or automatically. Referring to FIG. 1, reference numeral 10 denotes a vehicle drive unit for applying drive force to the drive wheels of vehicle 1, 11 denotes a braking device for braking vehicle 1, 12 denotes a steering device for steering vehicle 1, and 13 denotes an electronic control unit mounted in vehicle 1. As shown in FIG. 1, electronic control unit 13 is a digital computer and includes a CPU (processor) 15, memory 16 consisting of ROM and RAM, and input / output ports 17, all connected to each other by a bidirectional bus 14.

[0009] 1, the vehicle 1 is equipped with an accelerator pedal depression amount sensor (hereinafter referred to as accelerator position sensor) 18 that generates an output signal corresponding to the depression amount of the accelerator pedal, a brake pedal sensor 19 that generates an output signal corresponding to the depression pressure of the brake pedal, a vehicle speed sensor 20 that detects the speed of the vehicle 1, a longitudinal acceleration sensor 21 that can detect the longitudinal acceleration of the vehicle 1, and a rear object detection sensor 22 that can detect the approach of an object behind the vehicle 1, such as a car or a motorcycle. The rear object detection sensor 22 may be a medium-range millimeter-wave radar attached to the rear of the vehicle 1 that emits millimeter waves toward the rear of the vehicle 1, or a clearance sonar attached to the rear of the vehicle 1 that emits ultrasonic waves toward the rear of the vehicle 1. Output signals from the accelerator position sensor 18, brake pedal sensor 19, vehicle speed sensor 20, longitudinal acceleration sensor 21, and rear object detection sensor 22 are input to the electronic control unit 13. The electronic control unit 13 is connected to a communication device 23 for communicating with the outside.

[0010] 1, the vehicle drive unit 10 of the vehicle 1 is configured with an electric motor driven by a secondary battery or an electric motor driven by a fuel cell. When the accelerator pedal is depressed, an output signal corresponding to the amount of depression of the accelerator pedal is input from an accelerator position sensor 18 to an electronic control unit 13. At this time, an electric motor drive signal corresponding to the amount of depression of the accelerator pedal is output from the electronic control unit 13, and the drive wheels are driven and controlled by the electric motor in accordance with this electric motor drive signal.

[0011] Each wheel of the vehicle 1 is equipped with a hydraulically operated brake device, such as a disc brake, and the braking device 11 includes a hydraulic control unit for controlling the brake hydraulic pressure supplied to these brake devices. When the brake pedal is depressed, an output signal corresponding to the brake pedal depression force is input from a brake pedal sensor 19 to an electronic control unit 13. At this time, a brake hydraulic pressure signal corresponding to the brake pedal depression force is output from the electronic control unit 13, and this brake hydraulic pressure signal is input to the hydraulic control unit of the braking device 11 to control the braking action of each brake device. In the example shown in FIG. 1 , the hydraulic control unit also has a function of controlling the brake hydraulic pressure to a preset value higher than the brake hydraulic pressure corresponding to the brake pedal depression force. Meanwhile, the steering device 12 has a power steering function that assists the rotation of the steering wheel in response to the operation of the steering wheel.

[0012] Now, the present invention is such that, when it is determined that there is a possibility that an object, for example, a car or a motorcycle, will collide with the vehicle 1 from behind while the vehicle 1 is stopped, collision response braking control is performed to apply to the vehicle 1 a braking force required to suppress the forward movement of the vehicle 1 due to the collision of the object, and the vehicle 1 can be started immediately in accordance with the driver's intention even while such collision response braking control is being performed on the vehicle 1. Therefore, first, the problem that the present invention aims to solve and the means for solving the problem will be described with reference to Fig. 2 which shows a time chart of changes in related parameters when an object collides with the stopped vehicle 1 from behind.

[0013] 2, from top to bottom, there are shown changes in accelerator pedal depression amount, changes in brake pedal depression amount, changes in vehicle speed, changes in the distance between vehicle 1 and an object (e.g., a vehicle or motorcycle) traveling following vehicle 1, an indication of whether collision response braking control that automatically applies braking force to vehicle 1 is not being performed (OFF) or is being performed (ON), changes in forward acceleration G of vehicle 1, and an indication of whether a control execution continuation flag indicating that execution of collision response braking control should be continued is reset or set. Note that Fig. 2 shows a case where the accelerator pedal depression amount is zero, the brake pedal is depressed, the vehicle speed is zero, and vehicle 1 is stopped.

[0014] Now, taking as an example a case where a mid-range millimeter-wave radar is used as the rear object detection sensor 22 capable of detecting the approach of an object (e.g., a car or a motorcycle) behind the vehicle 1, the inter-vehicle distance is calculated from the time between the emission of millimeter waves and the reception of the millimeter waves reflected by the object, and the speed of the object is calculated from the change in the inter-vehicle distance over time. In an embodiment according to the present invention, the electronic control unit 13 determines whether or not the object is likely to collide with the vehicle 1 based on the calculated inter-vehicle distance and the calculated speed of the object. FIG. 2 shows a case where it is determined at time t1 that an object is likely to collide with the vehicle 1. When it is determined at time t1 that an object is likely to collide with the vehicle 1, as shown in FIG. 2, collision response braking control is initiated. Once collision response braking control is initiated, this collision response braking control continues for a predetermined period of time, unless collision response braking control is canceled midway.

[0015] 2, the brake pedal is depressed before the start of collision response braking control, and therefore, at this time, the brake hydraulic pressure of the brake device of each wheel is controlled to a hydraulic pressure corresponding to the brake pedal depression force by the hydraulic control unit of the braking device 11. Next, when collision response braking control is started, the brake hydraulic pressure of the brake device of each wheel is increased by the hydraulic control unit, and the brake hydraulic pressure of the brake device of each wheel is controlled to a preset hydraulic pressure higher than the hydraulic pressure corresponding to the brake pedal depression force.

[0016] On the other hand, the example shown by the solid line in Figure 2 shows a case where the inter-vehicle distance gradually decreases over time, and at time t2 the inter-vehicle distance becomes zero and an object collides with vehicle 1. When an object collides with vehicle 1, vehicle 1 is thrust forward by the colliding object, and as shown in Figure 2, the forward acceleration G of vehicle 1 increases suddenly, and even if collision braking control is being performed, vehicle 1 moves forward and the vehicle speed temporarily becomes positive, as shown in Figure 2. When vehicle 1 is thrust forward, the driver's body is pressed against the seat back, so the driver's foot comes off the brake pedal and the brake pedal pressure temporarily becomes zero, as shown in Figure 2.

[0017] When the brake pedal pressure temporarily becomes zero, the driver tries to depress the brake pedal to prevent the forward movement of vehicle 1. At this time, the driver is panicked and may mistake the accelerator pedal for the brake pedal, as shown in FIG. 2. Meanwhile, if an object collides with vehicle 1 and the forward acceleration G of vehicle 1 increases suddenly, and the tires of each wheel deform due to the sudden forward movement of vehicle 1, the reaction force of the deformation causes the vehicle body to swing backward, and the backward acceleration of vehicle 1 increases suddenly. In this case, the time t3 at which the backward acceleration starts to increase almost coincides with the time at which the driver starts to depress the brake pedal or the accelerator pedal, and after a while, at time t4, the backward acceleration swings back to the forward acceleration G.

[0018] As shown in Figure 2, after an object collides with vehicle 1, the accelerator pedal is depressed between time t3 and time t4 while rearward acceleration is occurring. In actual experiments, it was found that after an object collides with vehicle 1, the accelerator pedal is depressed between time t3 and time t4 while rearward acceleration is occurring.

[0019] Incidentally, even while collision response braking control is being performed on the vehicle 1, it is preferable to be able to immediately start the vehicle 1 when the driver intentionally depresses the accelerator pedal to start the vehicle 1. Therefore, in an embodiment of the present invention, even while collision response braking control is being performed, if the driver intentionally depresses the accelerator pedal, the collision response braking control is released and the driving force of the vehicle 1 can be adjusted in accordance with the accelerator pedal depression. On the other hand, if there is a high possibility that the accelerator pedal has been depressed involuntarily by the driver, the collision response braking control is continued and the accelerator pedal depression is treated as if it had not occurred.

[0020] In this case, it is highly likely that the accelerator pedal was depressed without the driver's consent between time t3 and time t4, when rearward acceleration is occurring, after the object collides with the vehicle 1. Therefore, in this embodiment of the present invention, a control execution continuation flag is set, indicating that execution of collision response braking control should be continued, between time t3 and time t4, when rearward acceleration is occurring, and if the accelerator pedal is also depressed while the control execution continuation flag is set, collision response braking control continues and the accelerator pedal depression is treated as not having occurred.

[0021] It is also possible to cancel the collision braking control and adjust the driving force of the vehicle 1 in accordance with the depression of the accelerator pedal if the rearward acceleration generated after an object collides with the vehicle 1 is weak. Therefore, in an embodiment of the present invention, only if the rearward acceleration generated after an object collides with the vehicle 1 is rearward acceleration of a predetermined magnitude or greater, the collision braking control is continued and the depression of the accelerator pedal is ignored. In this case, in an embodiment of the present invention, when the forward acceleration G caused to the vehicle 1 by the collision of the object exceeds the threshold value X, it is determined that the subsequent rearward acceleration is rearward acceleration of a predetermined magnitude or greater.

[0022] 3 shows a routine for executing the collision braking control according to the present invention. This routine is repeatedly executed in the electronic control unit 13 of the vehicle 1.

[0023] 3, first, in step 30, it is determined whether a braking control execution flag, which is set when collision braking control should be executed, is set. If it is determined that the braking control execution flag is not set, the process proceeds to step 31, where it is determined whether the vehicle 1 is stopped based on the output signal of the vehicle speed sensor 20. If it is determined that the vehicle 1 is not stopped, the processing cycle ends. On the other hand, if it is determined that the vehicle 1 is stopped, the process proceeds to step 32, where it is determined whether there is a possibility that an object will collide with the vehicle 1 from behind based on the output signal of the rear object detection sensor 22.

[0024] If it is determined in step 32 that there is no possibility that an object will collide with vehicle 1 from behind, the processing cycle is terminated. On the other hand, if it is determined that there is a possibility that an object will collide with vehicle 1 from behind, the processing proceeds to step 33, where a braking control execution flag is set. That is, when vehicle 1 is stopped and there is a possibility that an object will collide with vehicle 1 from behind, the braking control execution flag is set, and then the processing proceeds to step 34. If the braking control execution flag is set, in the next processing cycle, the processing jumps from step 30 to step 34. In step 34, it is determined whether a preset time t has elapsed since the braking control execution flag was set. If it is determined that the preset time t has not elapsed since the braking control execution flag was set, the processing proceeds to step 35, where a control execution continuation flag processing is executed, which indicates that the execution of collision-responsive braking control should be continued.

[0025] This control execution continuation flag processing is shown in Figure 4, and therefore, the control execution continuation flag processing shown in Figure 4 will be described first. Referring to Figure 4, in step 50, it is determined whether or not a control execution continuation flag, which indicates that the execution of collision braking control should be continued, is set. If it is determined that the control execution continuation flag is not set, it is determined whether or not a large acceleration flag, which indicates that rearward acceleration of a predetermined magnitude or greater has occurred, is set. If it is determined that the large acceleration flag is not set, the process proceeds to step 52, where it is determined whether or not the generated forward acceleration G has exceeded a threshold value X (Figure 2). If it is determined that the generated forward acceleration G has not exceeded the threshold value X, the process proceeds to step 36 in Figure 3.

[0026] On the other hand, if it is determined in step 52 that the generated forward acceleration G exceeds the threshold value X, the process proceeds to step 53, where a large acceleration flag is set, and then the process proceeds to step 54. That is, in this embodiment according to the present invention, when the forward acceleration G caused in the vehicle 1 due to a collision with an object exceeds the threshold value X, the subsequently generated rearward acceleration is determined to be a rearward acceleration of a predetermined magnitude or more, and when the forward acceleration G exceeds the threshold value X, the large acceleration flag is set. If the large acceleration flag is set, the process jumps from step 51 to step 54 in the next processing cycle.

[0027] In step 54, it is determined whether the generated forward acceleration G has become negative, i.e., whether backward acceleration has occurred. If it is determined that backward acceleration has not occurred, the process proceeds to step 36 in FIG. 3. On the other hand, if it is determined that backward acceleration has occurred, the process proceeds to step 55, where a control execution continuation flag is set, and then proceeds to step 36 in FIG. 3. If the control execution continuation flag is set, in the next processing cycle, the process proceeds from step 50 to step 56, where it is determined whether the forward acceleration G has become positive, i.e., whether the generation of backward acceleration has ended. If it is determined that the generation of backward acceleration has not ended, the process proceeds to step 36 in FIG. 3. On the other hand, if it is determined that the generation of backward acceleration has ended, the process proceeds to step 57, where the control execution continuation flag is reset, and then proceeds to step 36 in FIG. 3. Therefore, as long as backward acceleration of a predetermined magnitude or greater is occurring, the control execution continuation flag remains set unless it is reset.

[0028] Returning to FIG. 3 again, in step 36, it is determined from the output signal of the accelerator position sensor 18 whether the accelerator pedal has been depressed. If it is determined that the accelerator pedal has not been depressed, the process proceeds to step 37, where collision response braking control is executed. Then, the processing cycle is ended. On the other hand, if it is determined in step 36 that the accelerator pedal has been depressed, the process proceeds to step 38, where it is determined whether a control execution continuation flag, which is set while rearward acceleration of a predetermined magnitude or greater is occurring, has been set. If it is determined that the control execution continuation flag has been set, the process proceeds to step 39, where the accelerator pedal depression is invalidated. That is, it is determined that the accelerator pedal has not been depressed. Then, the process proceeds to step 37, where collision response braking control is executed.

[0029] On the other hand, if it is determined in step 38 that the control execution continuation flag is not set, the process proceeds to step 40, where the collision braking control is stopped. At this time, the driving force of the vehicle 1 is adjusted in response to the depression of the accelerator pedal, and the vehicle 1 is caused to immediately start moving. Next, in step 41, the braking control execution flag is reset. Then, the processing cycle is ended. On the other hand, if it is determined in step 34 that a preset time t has elapsed after the braking control execution flag was set, the process proceeds to step 40, where the collision braking control is stopped, and then, in step 41, the braking control execution flag is reset.

[0030] As described above, the vehicle control device according to the present invention includes an accelerator pedal for adjusting the driving force of the vehicle 1, an acceleration sensor 21 capable of detecting the acceleration of the vehicle 1 in the longitudinal direction, a detection sensor 22 capable of detecting an object approaching the vehicle 1 from behind, a braking device 11 that applies braking force to the vehicle, and a processor 15. When the processor 15 determines, based on the detection result of the detection sensor 22, that there is a possibility that an object will collide with the vehicle 1 from behind while the vehicle 1 is stopped, it causes the braking device 11 to perform collision response braking control that applies to the vehicle a braking force required to suppress forward movement of the vehicle due to the collision of the object. Furthermore, the processor 15 determines whether or not rearward acceleration is occurring in the vehicle due to the collision of an object during the collision braking control, and if the accelerator pedal is depressed when rearward acceleration is occurring during the collision braking control, the processor 15 continues the collision braking control and treats the accelerator pedal as not being depressed, and if the accelerator pedal is depressed when no rearward acceleration is occurring during the collision braking control, the processor 15 cancels the collision braking control and adjusts the driving force of the vehicle in accordance with the accelerator pedal depression. Note that in this case, the rearward acceleration is the rearward acceleration that occurs first in the vehicle 1 after the frontward acceleration occurs in the vehicle 1 due to the collision of an object.

[0031] Therefore, the vehicle control device according to the present invention makes it possible to immediately start the vehicle 1 in accordance with the driver's intention even during the collision response braking control of the vehicle 1. In this case, in the embodiment according to the present invention, when it is determined based on the detection result of the detection sensor 22 that there is a possibility that an object will collide with the vehicle 1 from behind while the vehicle 1 is stopped, the collision response braking control is performed by the brake device 11 for a predetermined fixed time unless the collision response braking control is canceled.

[0032] Furthermore, in an embodiment according to the present invention, processor 15 determines whether or not rearward acceleration of a predetermined magnitude or greater is occurring in the vehicle due to the collision of an object during collision braking control. If the accelerator pedal is depressed when rearward acceleration of a predetermined magnitude or greater is occurring during collision braking control, processor 15 continues collision braking control and treats the accelerator pedal as not being depressed. If the accelerator pedal is depressed when rearward acceleration of a predetermined magnitude or greater is not occurring during collision braking control, processor 15 cancels collision braking control and adjusts the vehicle's driving force in accordance with the accelerator pedal depression.

[0033] In reality, for example, a motorcycle may approach vehicle 1 from behind and then pass by the side of vehicle 1 without colliding. The change in inter-vehicle distance indicated by the dashed line in FIG. 2 illustrates such a case. In the example indicated by the dashed line in FIG. 2, the rear object detection sensor 22 determines that there is a possibility that the motorcycle will collide with vehicle 1, and collision response braking control is initiated. However, because the motorcycle does not collide with vehicle 1, rearward acceleration of vehicle 1 is not induced. Therefore, if the accelerator pedal is depressed while collision response braking control is being performed, collision response braking control is released and the vehicle can be started in response to depression of the accelerator pedal. In this way, even if collision response braking control is initiated due to the possibility that an object may collide with vehicle 1, if the object does not collide with vehicle 1, there is an advantage in that the vehicle can be started immediately in response to depression of the accelerator pedal. [Explanation of symbols]

[0034] 1. Your vehicle 11 Braking device 15 processors 18 Accelerator opening sensor 19 Brake pedal sensor 20 Vehicle speed sensor 21 Forward / backward acceleration sensor 22 Rear object detection sensor

Claims

1. The vehicle driving force adjusting system includes an accelerator pedal for adjusting the driving force of the vehicle, an acceleration sensor capable of detecting acceleration in the front-rear direction of the vehicle, a detection sensor capable of detecting an object approaching the vehicle from behind, a braking device for applying a braking force to the vehicle, and a processor, The processor When it is determined based on the detection result of the detection sensor that there is a possibility that an object will collide with the vehicle from behind while the vehicle is stopped, the braking device is caused to perform collision response braking control that applies to the vehicle a braking force necessary to suppress forward movement of the vehicle due to the collision of the object, During the collision braking control, it is determined whether or not rearward acceleration is occurring in the vehicle due to the collision of the object; During the collision response braking control, if the accelerator pedal is depressed while the rearward acceleration is occurring, the collision response braking control is continued and the accelerator pedal is not depressed, If the accelerator pedal is depressed when the rearward acceleration is not occurring during the collision response braking control, the vehicle control device cancels the collision response braking control and adjusts the driving force of the vehicle in accordance with the accelerator pedal depression.

2. 2. The vehicle control device according to claim 1, wherein when the processor determines based on the detection result of the detection sensor that there is a possibility that an object will collide with the vehicle from behind while the vehicle is stopped, the processor causes the braking device to perform the collision response braking control for a predetermined fixed time unless the collision response braking control is released.

3. 2. The vehicle control device according to claim 1, wherein the processor determines whether or not a rearward acceleration of a predetermined magnitude or greater is occurring in the vehicle due to the collision of the object during the collision response braking control, and if the accelerator pedal is depressed when rearward acceleration of the predetermined magnitude or greater is occurring during the collision response braking control, the processor continues the collision response braking control and treats the accelerator pedal as not being depressed, and if the accelerator pedal is depressed when rearward acceleration of the predetermined magnitude or greater is not occurring during the collision response braking control, the processor cancels the collision response braking control and adjusts the driving force of the vehicle in accordance with the accelerator pedal depression.

4. 2. The vehicle control device according to claim 1, wherein the rearward acceleration is the first rearward acceleration that occurs in the vehicle after a forward acceleration occurs in the vehicle due to a collision with the object.

Images