Speed ​​reduction control device

Abstract

The present invention provides a deceleration control device that can reduce the possibility of the driver feeling uneasy about the deceleration control due to the deceleration control being initiated even though the driver has not recognized the object to be decelerated. [Solution] When a predetermined starting condition is met, the deceleration control device starts deceleration control to decelerate the vehicle so that the vehicle's deceleration matches a predetermined target deceleration. The deceleration control device sets a starting distance required for the vehicle speed to match a predetermined target vehicle speed when the vehicle is decelerated at the target deceleration, and considers the starting condition to be met when the distance between the vehicle and the object to be decelerated in the direction of travel of the vehicle becomes less than or equal to the starting distance, and starts deceleration control. When the object to be decelerated is not in the driver's field of view, the target deceleration is set to a larger value than when the object to be decelerated is in the field of view, thereby shortening the starting distance compared to when the object to be decelerated is in the field of view.

Description

Technical Field

[0001] The present invention relates to a deceleration control device that executes deceleration control to decelerate a vehicle so that the deceleration of the vehicle matches a target deceleration when a predetermined start condition is satisfied.

Background Art

[0002] Conventionally, a deceleration control device that executes deceleration control when a deceleration target object exists in the traveling direction of a vehicle is known. For example, the deceleration control device described in Patent Document 1 (hereinafter referred to as the "conventional device") starts deceleration control when the distance between the vehicle and the deceleration target object is less than or equal to a deceleration travel distance. The deceleration travel distance is the distance that the vehicle travels until the "vehicle speed representing the speed of the vehicle" decreases to the "target vehicle speed corresponding to the deceleration target object".

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The conventional device may start deceleration control even though the driver does not recognize the deceleration target object. In this case, since the driver cannot grasp the intention of starting the deceleration control, there is a high possibility that the driver will feel uncomfortable with the deceleration control.

[0005] The present invention has been made to address the above-described problems. That is, one object of the present invention is to provide a deceleration control device that can reduce the possibility that a driver feels uncomfortable with deceleration control.

[0006] When a predetermined start condition is satisfied (step 350 "Yes"), the deceleration control device of the present invention (hereinafter referred to as the "device of the present invention") starts deceleration control (step 410) to decelerate the vehicle so that the deceleration of the vehicle matches a predetermined target deceleration (step 355). The aforementioned deceleration control device is The starting distance required for the vehicle speed, which represents the speed of the vehicle when the vehicle decelerates at the aforementioned target deceleration, to match a predetermined target vehicle speed is set (steps 340 and 370). When the distance between the vehicle and the object to be decelerated in the direction of travel of the vehicle becomes less than or equal to the starting distance (step 350 "Yes"), the starting condition is deemed to have been met, and the deceleration control is started (step 355). If the object to be decelerated is not located within the driver's field of view of the vehicle (step 325 "No"), the target deceleration is set to a value greater than that when the object to be decelerated is within the field of view (step 360), thereby shortening the starting distance compared to when the object to be decelerated is within the field of view (step 370). It is structured in this way.

[0007] According to the present invention, when the object to be decelerated is not in the field of view, the starting distance is shorter than when the object to be decelerated is in the field of view, so the timing of the start of deceleration control is delayed. As a result, there is a higher probability that the object to be decelerated will be in the field of view when deceleration control starts. Therefore, the possibility of deceleration control starting even though the driver has not recognized the object to be decelerated is reduced, and thus the possibility of the driver feeling uncomfortable with the deceleration control can be reduced. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic system configuration diagram of a deceleration control device according to an embodiment of the present invention. [Figure 2] This figure illustrates the operation of a deceleration control device according to an embodiment of the present invention. [Figure 3] Figure 1 is a flowchart of the start determination routine executed by the CPU of the ECU. [Figure 4] Figure 1 is a flowchart of the deceleration control routine executed by the CPU of the ECU. [Modes for carrying out the invention]

[0009] A deceleration control device 10 (hereinafter also referred to as "the device 10") according to an embodiment of the present invention is applied to a vehicle VA and comprises the components shown in Figure 1. In this specification, "ECU 20" is an electronic control device mainly comprising a microcomputer. The ECU 20 is also referred to as a control unit, controller, and computer. The microcomputer includes a CPU (processor), ROM, RAM, and interface (I / F), etc. The functions realized by the ECU 20 may be realized by multiple ECUs.

[0010] Camera 22 acquires image data by capturing the shooting area PA (see Figure 2) in front of the vehicle VA. ECU 20 acquires the image data from camera 22. GNSS (Global Navigation Satellite System) receiver 24 receives signals from multiple satellites and determines the current position (latitude and longitude) of the vehicle VA based on the received signals. ECU 20 acquires the current position of the vehicle VA from GNSS receiver 24. Acceleration sensor 26 measures the acceleration G in the longitudinal direction of the vehicle VA. Vehicle speed sensor 28 measures the vehicle speed Vs, which represents the speed of the vehicle VA. CPU acquires the measured values ​​from sensors 26 and 28. Storage device 30 has a map data storage unit 30a. Map data related to the position (latitude and longitude) of the deceleration target object DO, described later, is stored in the map data storage unit 30a.

[0011] The powertrain actuator 32 modifies the driving force generated by the vehicle VA's drive system (e.g., internal combustion engine and / or electric motor). The brake actuator 34 modifies the braking force applied to the vehicle VA.

[0012] <Deceleration control> The ECU 20 of this device 10 executes deceleration control when the start conditions described later are met. In deceleration control, the ECU 20 controls the powertrain actuator 32 and the brake actuator 34 so that the acceleration G of the vehicle VA matches the target deceleration Gtgt. Deceleration refers to a negative acceleration G. Deceleration control is performed so that the vehicle speed Vs (hereinafter referred to as "reached vehicle speed Vs") when the vehicle VA reaches the deceleration target DO (see Figure 2) matches the "target vehicle speed Vtgt determined according to the deceleration target DO". For example, the deceleration target DO is a curved road, a roundabout, a YIELD sign, a pedestrian crossing, a stop sign (or stop line), etc. For example, the target vehicle speed Vtgt decreases in the order of curved road, roundabout, YIELD sign, pedestrian crossing, and stop sign (or stop line). The ECU 20 detects the deceleration target DO in the direction of travel of the vehicle VA by referring to map data. Deceleration control is a type of automated driving to assist the driver.

[0013] The ECU20 determines that the start condition has been met and starts deceleration control when the distance D (see Figure 2) between the vehicle VA and the object DO to be decelerated becomes less than or equal to "the starting distance Dst required for the vehicle speed Vs to match the target vehicle speed Vtgt when the vehicle VA is decelerated at the target deceleration Gtgt." The target deceleration Gtgt is predetermined according to the type of object DO to be decelerated. For example, the target deceleration Gtgt is predetermined based on the average value of the deceleration degree of multiple drivers for each type of object DO to be decelerated. Furthermore, the distance D is obtained based on the position of the object DO to be decelerated on the map data and the current position of the vehicle VA.

[0014] (Summary of operation) The ECU20 determines whether the object to be decelerated, DO, is located within the field of view SA (see Figure 2). The field of view SA is the area in which the driver can perceive an object. As shown in Figure 2, the field of view SA is set as a sector-shaped area centered on a predetermined reference point of the vehicle VA. The sector that constitutes the field of view SA has a central angle θ and a radius R.

[0015] If the object to be decelerated DO is not in the field of view SA, there is a high probability that the driver is not aware of that object DO. If deceleration control is initiated when the driver is not aware of the object DO, the driver is unlikely to understand the intention behind initiating the deceleration control, and is therefore likely to feel that the deceleration control is inconsistent.

[0016] Therefore, the ECU20 delays the start of deceleration control if the object DO to be decelerated is not in the field of view SA, compared to when the object DO is in the field of view SA. By delaying the start of deceleration control, the likelihood of the object DO coming into the field of view SA increases. When the object DO comes into the field of view SA, the likelihood of the driver recognizing the object DO increases. Consequently, the possibility of deceleration control being started even though the driver has not recognized the object DO is reduced, thus reducing the likelihood of the driver feeling something is wrong with the deceleration control.

[0017] In detail, the ECU20 sets the target deceleration Gtgt when the object DO to be decelerated is not in the field of view SA to a larger value than the target deceleration Gtgt when the object DO to be decelerated is in the field of view SA. As a result, the starting distance Dst when the object DO to be decelerated is not in the field of view SA is shorter than the starting distance Dst when the object DO to be decelerated is in the field of view SA. Therefore, when the object DO to be decelerated is not in the field of view SA, the start timing of deceleration control is delayed compared to when the object DO to be decelerated is in the field of view SA.

[0018] More specifically, if the object to be decelerated DO is not in the field of view SA, the ECU20 sets the target deceleration Gtgt to the maximum allowable deceleration Gdmax. The maximum allowable deceleration Gdmax is the maximum deceleration permitted by the deceleration control. The starting distance Dst obtained based on the maximum allowable deceleration Gdmax is referred to as the "limit starting distance Dlmt".

[0019] On the one hand, when the deceleration target object DO exists in the visual field area SA, the ECU 20 sets the target deceleration Gtgt to the normal deceleration Gd. The normal deceleration Gd is set according to the type of the deceleration target object DO and is smaller than the maximum allowable deceleration Gdmax. The starting distance Dst obtained based on the normal deceleration Gd is referred to as the "normal starting distance Dnor".

[0020] Since the maximum allowable deceleration Gdmax is larger than the normal deceleration Gd, as shown in Figure 2, the limit starting distance Dlmt is shorter than the normal starting distance Dnor. As a result, when the deceleration target object DO does not exist in the visual field area SA, the start timing of the deceleration control is delayed compared to the case where the deceleration target object DO exists in the visual field area SA. Note that even when the deceleration target object DO does not exist in the visual field area SA, when the distance D becomes less than or equal to the limit starting distance Dlmt, the vehicle VA decelerates at the maximum allowable deceleration Gdmax, so the arrival vehicle speed Vs can be made to match the target vehicle speed Vtgt.

[0021] (Specific operation) The CPU of the ECU 20 executes the routine shown by the flowchart in Figures 3 and 4 every time a predetermined time elapses.

[0022] <Start determination routine> When an appropriate time point arrives, the CPU starts processing from step 300 in Figure 3. In step 305, the CPU determines whether the execution flag Xexe is "0". The execution flag Xexe is set to "1" when the deceleration control is executed and is set to "0" when the deceleration control is not executed. The execution flag Xexe is set to "0" in the initialization routine. The initialization routine is executed by the CPU when an ignition key switch (not shown) of the vehicle VA is changed from the off position to the on position.

[0023] If the execution flag Xexe is "0", the CPU determines "Yes" in step 305, and the process proceeds to step 310. In step 310, the CPU determines whether the setting flag Xset is "0". The setting flag Xset is set to "1" if the starting distance Dst is set, and to "0" if the starting distance Dst is not set. The setting flag Xset is set to "0" in the initialization routine.

[0024] If the setting flag Xset is "0", the CPU determines "Yes" in step 310, and the process proceeds to step 315. In step 315, the CPU refers to the map data and determines whether or not there is a deceleration target object DO within a predetermined distance in the direction of travel of vehicle VA from the vehicle VA's current position.

[0025] If there is no object DO to be decelerated, deceleration control will not be started. In this case, the CPU determines "No" in step 315, and the process proceeds to step 395. In step 395, the CPU terminates this routine.

[0026] If there is an object DO to be decelerated, the CPU determines "Yes" in step 315 and executes steps 320 and 325.

[0027] Step 320: The CPU sets the field of view SA at the current location of the vehicle VA on the map data. In detail, the CPU determines, based on the image data, whether or not there is an obstruction BL (see Figure 2) of a predetermined height that obstructs the driver's view around the vehicle VA. If no obstruction BL exists, the CPU sets the above-mentioned fan-shaped region as the field of view SA. On the other hand, if an obstruction BL exists, the CPU identifies the region within the above-mentioned fan-shaped region where a line passing through the reference point of the vehicle VA intersects with the obstruction BL (i.e., the region where the view is obstructed by the obstruction BL). The CPU excludes that region from the field of view SA. In the example shown in Figure 2, the lightly blacked-out region is excluded from the field of view SA.

[0028] Step 325: The CPU determines whether the object to be decelerated DO is located in the field of view SA.

[0029] If the object to be decelerated DO is in the field of view SA, the CPU determines "Yes" in step 325 and executes steps 330 to 350. Step 330: The CPU sets the target deceleration Gtgt to the deceleration Gd corresponding to the object DO being decelerated. Step 335: The CPU obtains the normal starting distance Dnor based on the current vehicle speed Vs, the target vehicle speed Vtgt corresponding to the deceleration object DO, and the deceleration Gd. The normal starting distance Dnor is the distance a vehicle VA travels when decelerating at a deceleration rate Gd until its current speed Vs matches the target speed Vtgt. Step 340: The CPU sets the starting distance Dst to the normal starting distance Dnor. Step 345: The CPU sets the configuration flag Xset to "1". Step 350: The CPU determines whether distance D is less than or equal to the starting distance Dst.

[0030] If distance D is longer than the starting distance Dst, the CPU determines that the starting condition is not met. In this case, the CPU determines "No" in step 350, and the process proceeds to step 395.

[0031] On the other hand, if distance D is less than or equal to the starting distance Dst, the CPU determines that the starting condition is met. In this case, the CPU determines "Yes" in step 350, and the process proceeds to step 355. In step 355, the CPU sets the execution flag Xexe to "1". After that, the process proceeds to step 395.

[0032] If the deceleration target DO is not within the field of view SA when the process proceeds to step 325, the CPU determines "No" in step 325 and executes steps 360 to 370.

[0033] Step 360: The CPU sets the target deceleration Gtgt to the maximum allowable deceleration Gdmax. Step 365: The CPU obtains the limit starting distance Dlmt based on the current vehicle speed Vs, the target vehicle speed Vtgt corresponding to the deceleration object DO, and the maximum allowable deceleration Gdmax. The limit starting distance Dlmt is the distance that vehicle VA travels when decelerating at the maximum allowable deceleration Gdmax, until the current vehicle speed Vs matches the target vehicle speed Vtgt. Step 370: The CPU sets the starting distance Dst to the limit starting distance Dlmt. The process then proceeds to step 345.

[0034] If the setting flag Xset is "1" when the process proceeds to step 310, the CPU determines "No" in step 310, and the process proceeds to step 375. In step 375, the CPU determines whether the starting distance Dst is set to the limit starting distance Dlmt.

[0035] If the starting distance Dst is set to the limit starting distance Dlmt, that is, if the object to be decelerated DO was not within the field of view SA when the starting distance Dst was set, the CPU determines "Yes" in step 375 and proceeds to step 380. In step 380, the CPU determines whether or not the object to be decelerated DO is now within the field of view SA. Even if the object to be decelerated DO was not within the field of view SA when the starting distance Dst was set, it is possible that the object to be decelerated DO may come into the field of view SA as the vehicle VA travels thereafter.

[0036] If the object DO to be decelerated is now within the field of view SA, the CPU determines "Yes" in step 380, and the process proceeds to step 385. In step 385, the CPU determines whether the distance D is less than or equal to the normal starting distance Dnor.

[0037] If distance D is longer than the normal starting distance Dnor, the CPU determines "No" in step 385, and processing proceeds to step 330 and beyond. The CPU sets the target deceleration Gtgt to deceleration Gd and the starting distance Dst to the normal starting distance Dnor.

[0038] If the distance D is less than or equal to the normal starting distance Dnor, the CPU determines that the starting condition is met. In this case, the CPU determines "Yes" in step 385, and the process proceeds to step 390. In step 390, the CPU sets the target deceleration Gtgt to the required deceleration Gd'. The required deceleration Gd' is the deceleration required for the vehicle VA to reach the current vehicle speed Vs and the target vehicle speed Vtgt while traveling a distance D. The required deceleration Gd' is obtained based on the current vehicle speed Vs, the target vehicle speed Vtgt, and the distance D.

[0039] After step 390 is executed, the process proceeds to step 355, where the execution flag Xexe is set to "1". Then the process proceeds to step 395.

[0040] If the object to be decelerated DO is not within the field of view SA when the starting distance Dst is set, and the object to be decelerated DO comes into the field of view SA when the distance D is less than or equal to the normal starting distance Dnor, the CPU will perform deceleration control with the required deceleration Gd' such that when the vehicle VA reaches the object to be decelerated DO, the vehicle speed Vs matches the target vehicle speed Vtgt. This reduces the possibility that the driver may feel uneasy due to the driver recognizing the object to be decelerated DO but no deceleration control being performed.

[0041] If the deceleration target DO is not within the field of view SA when the process proceeds to step 380, the CPU determines "No" in step 380. In this case, the process proceeds to step 350, where the CPU determines whether the distance D is less than or equal to the starting distance (i.e., the limit starting distance Dlmt).

[0042] If the starting distance Dst is set to the normal starting distance Dnor when the process proceeds to step 375 (i.e., if the object DO to be decelerated is within the field of view SA when the starting distance Dst is set), the CPU determines "No" in step 375 and the process proceeds to step 350.

[0043] If the execution flag Xexe is "1" when the process proceeds to step 305, the CPU determines "No" in step 305, and the process proceeds to step 395.

[0044] <Deceleration control routine> When the appropriate time arrives, the CPU starts processing from step 400 in Figure 4, and in step 405, the CPU determines whether the execution flag Xexe is "1".

[0045] If the execution flag Xexe is "0", the CPU determines "No" in step 405, and the process proceeds to step 495. In step 495, the CPU terminates this routine.

[0046] If the execution flag Xexe is "1", the CPU determines "Yes" in step 405 and executes steps 410 and 415.

[0047] Step 410: The CPU controls the powertrain actuator 32 and the brake actuator 34 so that the acceleration G of the vehicle VA matches the target deceleration Gtgt. Step 415: The CPU determines whether the vehicle VA has reached the point of the deceleration target DO.

[0048] If vehicle VA has not reached the location of the deceleration target DO, the CPU determines "No" in step 415, and the process proceeds to step 495. On the other hand, if vehicle VA has reached the location of the deceleration target DO, the CPU determines "Yes" in step 415, and the process proceeds to step 420. In step 420, the CPU sets the execution flag Xexe and the setting flag Xset to "0". After that, the process proceeds to step 495.

[0049] As explained above, when the object to be decelerated DO is not in the field of view SA, the starting distance Dst is shorter than when the object to be decelerated DO is in the field of view SA. This allows the start timing of deceleration control to be delayed, increasing the likelihood that the object to be decelerated DO will be in the field of view SA when deceleration control begins. Therefore, the possibility of deceleration control starting even though the driver has not recognized the object to be decelerated DO is reduced, thus reducing the possibility of the driver feeling that the deceleration control is unnatural.

[0050] Furthermore, if the object DO to be decelerated is not present in the field of view SA, and the starting distance Dst is initially set to the limit starting distance Dlmt, but then the object DO comes into the field of view SA when the distance D becomes less than or equal to the normal starting distance Dnor, deceleration control will be executed using the required deceleration Gd'. This reduces the possibility that the driver may feel uneasy due to the driver recognizing the object DO to be decelerated but not receiving deceleration control.

[0051] (modified version) In the above embodiment, when the starting distance Dst is set to the limit starting distance Dlmt, and then the distance D becomes less than or equal to the normal starting distance Dnor and the object DO to be decelerated is located in the field of view SA, the ECU 20 considers that the starting conditions have been met and sets the target deceleration Gtgt to the required deceleration Gd' to start deceleration control. However, the ECU 20 is not limited to this. That is, even if the starting distance Dst is set to the limit starting distance Dlmt and then the object DO to be decelerated is located in the field of view SA, the ECU 20 does not need to start deceleration control until the distance D becomes less than or equal to the limit starting distance Dlmt.

[0052] In the above embodiment, in steps 415 and 420 shown in Figure 4, the ECU 20 terminates deceleration control when the vehicle VA reaches the point corresponding to the object DO to be decelerated, but it is not limited to this. For example, the ECU 20 may terminate deceleration control when the vehicle speed Vs matches the target vehicle speed Vtgt.

[0053] In the above embodiment, the deceleration Gd was obtained according to the object DO being decelerated, but a constant deceleration Gd may be obtained regardless of the object DO being decelerated.

[0054] In the above embodiment, map data was referenced to determine whether or not a deceleration target object DO exists, but this is not limited to that. For example, the presence or absence of a deceleration target object DO may be determined based on image data, or based on environmental data around the vehicle VA obtained by communicating with an external device. Furthermore, the distance D was obtained based on the position of the deceleration target object DO on the map data and the current position of the vehicle VA, but this is not limited to that. For example, the distance D may be obtained based on image data or the environmental data mentioned above. Moreover, the field of view SA is not limited to a fan shape.

[0055] This device 10 is applicable to vehicles such as engine-powered vehicles, hybrid vehicles, plug-in hybrid vehicles, fuel cell vehicles, and electric vehicles. [Explanation of Symbols]

[0056] 10... Deceleration control device, 20... ECU, 26... Acceleration sensor, 30a... Map data storage unit, 32... Powertrain actuator, 34... Brake actuator.

Claims

1. In a speed control device that initiates deceleration control to decelerate the vehicle so that the vehicle's deceleration matches a predetermined target deceleration when predetermined starting conditions are met, The aforementioned deceleration control device is When the vehicle decelerates at the aforementioned target deceleration rate, a starting distance is set that is necessary for the vehicle speed, which represents the speed of the vehicle, to match a predetermined target vehicle speed. When the distance between the vehicle and the object to be decelerated in the direction of travel of the vehicle becomes less than or equal to the starting distance, the starting condition is deemed to have been met, and the deceleration control is started. When the object to be decelerated is not located within the driver's field of view of the vehicle, the target deceleration is set to a value greater than that when the object to be decelerated is within the field of view, thereby shortening the starting distance compared to when the object to be decelerated is within the field of view. A deceleration control device configured as follows.

2. In the deceleration control device according to claim 1, The aforementioned deceleration control device is In the deceleration control described above, the vehicle is decelerated so as not to exceed a predetermined maximum allowable deceleration. If the object to be decelerated is not present in the field of view, the starting distance is set to the limit starting distance at which the vehicle travels until the vehicle speed matches the target vehicle speed when the vehicle is decelerated at the maximum allowable deceleration, the target deceleration is set to the maximum allowable deceleration, and the deceleration control is executed. If the object to be decelerated is present in the field of view, the starting distance is set to the normal starting distance at which the vehicle travels until the vehicle speed matches the target vehicle speed when the vehicle is decelerated at a predetermined deceleration less than the maximum allowable deceleration, the target deceleration is set to the predetermined deceleration, and the deceleration control is executed. A deceleration control device configured as follows.

3. In the deceleration control device according to claim 2, The aforementioned deceleration control device is After setting the starting distance to the limit starting distance, if the distance becomes less than or equal to the normal starting distance and the object to be decelerated is located within the field of view, the target deceleration is set to the necessary deceleration required for the vehicle speed to match the target vehicle speed while the vehicle travels the distance, and the deceleration control is executed. A deceleration control device configured as follows.

4. In the deceleration control device according to claim 1, The aforementioned deceleration control device is Based on the map data in which the location of the object to be decelerated is registered, the location of the object to be decelerated is identified. Based on the image data obtained by photographing the area in the direction of travel of the vehicle, if an obstruction exists, the field of view is set excluding the area obstructed by the obstruction. A deceleration control device configured as follows.

Images