Vehicle speed limiting device

Abstract

The present application provides a vehicle speed limiting device which can correct an upper limit vehicle speed with a low possibility that the driver feels troublesome in the case where the upper limit vehicle speed is erroneously recognized. The vehicle speed limiting device performs vehicle speed limiting control to limit the vehicle speed so that the vehicle speed representing the speed of the vehicle does not exceed the upper limit vehicle speed. In the vehicle speed limiting device, in the case where the limit vehicle speed of the road on which the vehicle travels is newly recognized, the upper limit vehicle speed is changed to the limit vehicle speed, and in the case where the operation of the acceleration operation member or the deceleration operation member of the driver satisfies a prescribed reset condition during a reset period from the change point of time at which the upper limit vehicle speed is changed until the prescribed time elapses, the upper limit vehicle speed is reset to the upper limit vehicle speed before the change.

Description

Technical Field

[0001] The present invention relates to a vehicle speed limiting device that performs vehicle speed limiting control to limit the vehicle speed so that the vehicle speed representing the vehicle speed does not exceed the upper limit speed. Background Technology

[0002] Conventional speed limiting devices are known to perform speed limiting control to restrict vehicle speed so that it does not exceed the speed limit of the road on which the vehicle is traveling. For example, the speed limiting device described in Patent Document 1 (hereinafter referred to as the "conventional device") acquires the speed limit of the road on which the vehicle is traveling in real time and sets the upper limit speed as the upper limit speed. The conventional device ensures that the vehicle travels at a speed not exceeding the upper limit speed and displays the upper limit speed and the speed limit. In the conventional device, if the driver determines that the speed limit has been erroneously detected, the driver can perform a correction operation on the switch used to correct the upper limit speed.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-58436 Summary of the Invention

[0004] In previous systems, if the speed limit was incorrectly identified (detected), the driver needed to operate a switch. Drivers might find this operation cumbersome.

[0005] This invention was made to solve the aforementioned problems. Specifically, one of the objectives of this invention is to provide a vehicle speed limiting device that can correct the upper speed limit with an operation that is unlikely to be cumbersome for the driver, in the event that the vehicle speed limit is incorrectly identified.

[0006] The vehicle speed limiting device of the present invention (hereinafter referred to as "the device of the present invention") performs vehicle speed limiting control to limit the vehicle speed so that the vehicle speed, which represents the speed of the vehicle, does not exceed the upper limit vehicle speed.

[0007] The vehicle speed limiting device is configured as follows:

[0008] If the speed limit of the road on which the vehicle is traveling is re-identified (step 310 "Yes"), the upper speed limit is changed to the speed limit (step 335).

[0009] If the driver's acceleration or deceleration operation meets the prescribed reset conditions during the reset period from the time when the upper limit speed was changed until the specified time has elapsed (step 410 "Yes", step 425 "Yes", step 345 "Yes"), the upper limit speed is reset to the upper limit speed before the change (step 360).

[0010] Therefore, if the speed limit is incorrectly identified, the driver can simply operate the acceleration or deceleration control to set the upper speed limit back to the original speed limit. Thus, the speed limit can be corrected with an operation that is unlikely to be cumbersome for the driver. Attached Figure Description

[0011] Figure 1 This is a schematic system structure diagram of the vehicle speed limiting device according to an embodiment of the present invention.

[0012] Figure 2 This is a timing diagram illustrating the vehicle speed, throttle opening, and braking force of an example of the operation of the vehicle speed limiting device according to an embodiment of the present invention.

[0013] Figure 3 yes Figure 1 The flowchart shown is a process executed by the CPU of the ECU to set the upper limit vehicle speed.

[0014] Figure 4 yes Figure 1 The flowchart shown is of the reset condition determination subroutine executed by the CPU of the ECU. Detailed Implementation

[0015] The vehicle speed limiting device 10 (hereinafter also referred to as "this device 10") according to the embodiments of the present invention is applicable to vehicle VA and has the following features: Figure 1 The components are shown below. In this specification, "ECU20" is an electronic control device with a microcomputer as its main component. ECU20 is also referred to as a control unit, controller, and computer. The microcomputer includes a CPU (processor), ROM, RAM, and interfaces (I / F), etc. The functions performed by ECU20 can be implemented by multiple ECUs.

[0016] Camera 22 acquires image data by photographing the scenery in front of vehicle VA. ECU 20 acquires the image data from camera 22 and identifies the speed limit Vlmt of the road on which vehicle VA is traveling based on the image data.

[0017] Vehicle speed sensor 24 measures vehicle speed Vs, representing the speed of vehicle VA. Acceleration sensor 26 measures the longitudinal acceleration G of vehicle VA. Throttle opening sensor 28 measures throttle opening AP, representing the amount of pressure applied to the accelerator pedal (acceleration control) 28a. Throttle opening AP is sometimes also referred to as "acceleration operation amount". Brake operation amount sensor 30 measures brake operation amount BP, representing the amount of pressure applied to the brake pedal (deceleration control) 30a. Brake operation amount BP is sometimes also referred to as "deceleration operation amount". ECU 20 acquires the measurements from these sensors 26 to 32.

[0018] The powertrain actuator 32 alters the driving force generated by the drive unit (e.g., internal combustion engine and / or electric motor) of the vehicle VA. The brake actuator 34 alters the braking force applied to the vehicle VA.

[0019] <Speed ​​Limit Control>

[0020] ECU20 performs speed limit control to restrict vehicle speed Vs so that Vs does not exceed the upper speed limit Vup. ECU20 detects speed signs and road markings based on image data and identifies the speed limit Vlmt represented by these features. ECU20 sets the identified speed limit Vlmt as the upper speed limit Vup.

[0021] ECU20 acquires the limiting acceleration Gtgt used to make the vehicle speed Vs match the upper limit vehicle speed Vup. ECU20 also acquires the limiting braking force Flmt required to make the acceleration G match the limiting acceleration Gtgt. Regarding this limiting braking force Flmt, ECU20 acquires the smaller of the "driver-required braking force Freq corresponding to the throttle opening AP or brake operation amount BP" and the limiting braking force Flmt as the target braking force Ftgt.

[0022] The target braking force Ftgt can be positive or negative. When the target braking force Ftgt is positive, ECU 20 applies driving force to vehicle VA. Specifically, ECU 20 controls powertrain actuator 32 to make the driving force consistent with the positive target braking force Ftgt. On the other hand, when the target braking force Ftgt is negative, ECU 20 applies braking force to vehicle VA. Specifically, ECU 20 controls powertrain actuator 32 and brake actuator 34 to make the braking force consistent with the negative target braking force Ftgt.

[0023] Furthermore, when the driver depresses the accelerator pedal at 28a, the driver's required braking force Freq is positive. The larger the accelerator pedal opening AP, the larger the driver's required braking force Freq. When the driver depresses the brake pedal at 30a, the driver's required braking force Freq is negative. The larger the brake application amount BP, the smaller the driver's required braking force Freq.

[0024] (Action Summary)

[0025] Upon re-identifying the speed limit Vlmt, ECU20 changes the upper speed limit Vup to "the re-identified speed limit Vlmt". The point at which the upper speed limit Vup is changed (refer to...) Figure 2If the operation of the accelerator pedal 28a or brake pedal 30a meets the reset conditions during the reset period from the time of change to the time of reset Tres, the ECU20 will reset the upper limit speed Vup to the limit speed Vlmt (the speed Vold before the change).

[0026] When the maximum vehicle speed Vup is set to "the incorrectly recognized speed limit Vlmt", the driver can restore the maximum vehicle speed Vup to its original state by operating the accelerator pedal 28a or the brake pedal 30a. The driver is unlikely to find operating the accelerator pedal 28a or the brake pedal 30a cumbersome. Therefore, when the maximum vehicle speed Vup is changed to "the incorrectly recognized speed limit Vlmt", the maximum vehicle speed Vup can be corrected with an operation that is unlikely to be cumbersome for the driver.

[0027] Furthermore, when the upper limit speed Vup is changed to be lower than the previous speed Vold, when the operation of the accelerator pedal 28a is "acceleration intention operation indicating the driver's acceleration intention", the ECU 20 resets the upper limit speed Vup to the previous speed Vold.

[0028] If the speed limit Vlmt is incorrectly identified as being less than the actual speed limit Vlmt, the upper speed limit Vup will be less than the original speed Vold. In this case, the vehicle VA decelerates to bring the speed Vs to match the "incorrectly identified speed limit Vlmt". Therefore, the driver accelerates the vehicle VA (with acceleration intention) to bring the speed Vs to match the actual speed limit Vlmt, and operates the accelerator pedal 28a. Thus, as described above, when the operation of the accelerator pedal 28a is an acceleration intention operation, the upper speed limit Vup is reset to the original speed Vold, thereby reducing the likelihood that the driver will find the operation of correcting the upper speed limit Vup cumbersome.

[0029] Furthermore, when the upper limit speed Vup is changed to be greater than the previous speed Vold, when the operation of the accelerator pedal 28a or the brake pedal 30a is "a deceleration intention operation indicating the driver's intention to decelerate", the ECU 20 will reset the upper limit speed Vup to the previous speed Vold.

[0030] If the speed limit Vlmt is incorrectly identified as being greater than the actual speed limit Vlmt, the upper speed limit Vup will be greater than the previous speed Vold. In this case, the vehicle VA accelerates to bring the speed Vs to match the incorrectly identified speed limit Vlmt. Therefore, the driver decelerates the vehicle VA (with the intention to decelerate) to bring the speed Vs to match the actual speed limit Vlmt, by operating the accelerator pedal 28a or the brake pedal 30a. Therefore, as described above, when the operation of the accelerator pedal 28a or the brake pedal 30a is an operation with the intention to decelerate, and the upper speed limit Vup is reset to the previous speed Vold, the driver is less likely to find the operation for correcting the upper speed limit Vup cumbersome.

[0031] (Example of action)

[0032] refer to Figure 2 The operation of this device 10 will be explained using examples.

[0033] At time t1, the driver depresses the accelerator pedal 28a until the accelerator opening AP reaches 70%. Therefore, the driver requests an increase in the braking force Freq. Additionally, at time t1, the maximum vehicle speed Vup is set to 50 km / h, and the vehicle speed Vs is sufficiently lower than the maximum speed Vup. Therefore, the limiting braking force Flmt is greater than the driver's requested braking force Freq. Therefore, the target braking force Ftgt is set to the driver's requested braking force Freq, and thus, after time t1, the vehicle speed Vs increases.

[0034] Then, if the vehicle speed Vs approaches the maximum vehicle speed Vup, the limiting braking force Flmt is less than the driver's required braking force Freq. At time t2, the vehicle speed Vs is consistent with the maximum vehicle speed Vup ("50 km / h"). After time t2, even if the driver depresses the accelerator pedal 28a, the vehicle VA maintains the vehicle speed Vs at "50 km / h" and continues to travel.

[0035] At time t3, the speed limit Vlmt (“70km / h”) is re-identified, and the upper speed limit Vup is set to “70km / h”. The braking force Flmt is increased until it matches the driver's required braking force Freq. The vehicle speed Vs increases from “50km / h” until it matches “70km / h”. After the point where the vehicle speed Vs matches “70km / h”, the vehicle VA travels at “70km / h”.

[0036] Then, at time t4, the speed limit Vlmt ("30 km / h") is re-identified, and the upper speed limit Vup is set to "30 km / h". In other words, the upper speed limit Vup is changed to be less than the previous speed Vold (70 km / h). In this case, the braking force Flmt becomes negative, and the vehicle VA begins to decelerate. However, the speed limit Vlmt ("30 km / h") is incorrectly identified. Therefore, the driver presses the accelerator pedal 28a to accelerate the vehicle VA. At time t5, the operation of the accelerator pedal 28a is determined to be an acceleration intention operation, and the upper speed limit Vup is changed back to the previous speed Vold (70 km / h). In addition, time t5 is the period from the time of the change of the upper speed limit Vup (t4) until time t6 of the reset time Tres.

[0037] Furthermore, if either the first acceleration intention condition AC1 or the second acceleration intention condition AC2 is met, the operation of the accelerator pedal 28a is determined to be an acceleration intention operation.

[0038] The first acceleration intention condition AC1 is valid if both conditions AC1a and AC1b are true.

[0039] Condition AC1a: Throttle opening AP has increased by a specified percentage (e.g., 20%) or more since the time of the change.

[0040] Condition AC1b: The rate of change of throttle opening AP during the period from the time of change until the throttle opening AP increases by a specified percentage or more is greater than the specified threshold rate of change.

[0041] In addition, the rate of change represents the amount of change in throttle opening AP per specified unit of time.

[0042] The second acceleration intention condition AC2 is valid if both conditions AC2a and AC2b are true.

[0043] Condition AC2a: The throttle opening AP at the time of change is less than the threshold opening APth (e.g., 90%), and the throttle opening AP becomes greater than or equal to the threshold opening APth within a specified time from the time of change.

[0044] Condition AC2b: The rate of change of throttle opening AP during the period from the time of change to the time when the throttle opening AP becomes a threshold opening APth or higher is greater than the specified threshold rate of change.

[0045] exist Figure 2At time t5, the second acceleration intention condition is met. Therefore, when the maximum speed Vup is changed to be less than the previous speed Vold (70 km / h), the maximum speed Vup is changed back to the previous speed Vold based on the operation of the accelerator pedal 28a. This reduces the likelihood that the driver will find the operation for changing the maximum speed Vup cumbersome.

[0046] (Specific actions)

[0047] <Upper Speed ​​Setting Program>

[0048] The CPU of ECU20 executes the command every time a specified time has elapsed. Figure 3 The flowchart illustrates the procedure for setting the upper speed limit. If the appropriate time arrives, the CPU executes... Figure 3 Steps 300 and 310.

[0049] Step 305: The CPU acquires image data from camera 22.

[0050] Step 310: The CPU determines whether the speed limit Vlmt has been re-identified.

[0051] If the vehicle speed limit Vlmt is not re-identified, the CPU determines "No" in step 310 and proceeds to step 315. In step 315, the CPU determines whether the reset flag Xres is "1". If it is within the reset period, the reset flag Xres is set to "1"; otherwise, it is set to "0". The execution flag Xexe is set to "0" in the initialization procedure. The initialization procedure is executed by the CPU when the ignition key switch (not shown) on the vehicle VA changes from the off position to the on position.

[0052] If the flag Xres is reset to "0", the CPU determines "No" in step 315 and proceeds to step 395. In step 395, the CPU temporarily terminates the current program.

[0053] If the speed limit Vlmt is re-identified when proceeding to step 310, the CPU determines "yes" in step 310 and proceeds to step 320. In step 320, the CPU determines whether the upper speed limit Vup is the same as the re-identified speed limit Vlmt. In other words, the CPU determines whether the re-identified speed limit Vlmt is the same as the previously identified speed limit Vlmt.

[0054] If the upper limit speed Vup is different from the re-identified limit speed Vlmt, the CPU determines "no" in step 320 and executes steps 325 to 345.

[0055] Step 325: The CPU sets the reset flag Xres to "1" and the timer T to "0". Timer T is a timer used to count the time elapsed since the change of the upper limit speed Vup.

[0056] Step 330: The CPU sets the previous vehicle speed Vold to the current upper limit vehicle speed Vup.

[0057] Step 335: The CPU sets the upper limit speed Vup to the re-identified vehicle speed limit Vlmt. In other words, the CPU overwrites the upper limit speed Vup with the re-identified vehicle speed limit Vlmt.

[0058] Step 340: The CPU executes the reset condition determination subroutine to determine whether the reset condition is true. Details of the reset condition determination subroutine will be described later.

[0059] Step 345: The CPU determines whether the reset conditions are met.

[0060] If the reset condition is not met, the CPU determines "no" in step 345 and proceeds to step 395.

[0061] If the flag Xres is reset to "1" when entering step 315, the CPU determines "yes" in step 315 and executes steps 350 and 355.

[0062] Step 350: The CPU performs an addition operation of "1" on timer T.

[0063] Step 355: The CPU determines whether timer T is above the specified threshold Tth. If timer T is above the threshold Tth, the threshold Tth is set by elapsed time Tres from the change point of the upper limit vehicle speed Vup.

[0064] If the timer T is less than the threshold Tth, the CPU determines "no" in step 355 and proceeds to step 340.

[0065] If the reset condition is met when entering step 345, the CPU determines "yes" in step 345 and executes steps 360 and 365.

[0066] Step 360: The CPU sets the upper limit vehicle speed Vup to the original vehicle speed Vold.

[0067] Step 365: The CPU sets the reset flag Xres to "0" and the timer T to "0".

[0068] Next, the process proceeds to step 395.

[0069] On the other hand, if timer T is above threshold Tth when processing enters step 355, the CPU determines "yes" in step 355 and processes to enter step 365.

[0070] <Reset Condition Determination Subroutine>

[0071] If the process proceeds to step 340, the CPU will then... Figure 4 The process begins at step 400 and proceeds to step 405. In step 405, the CPU determines whether the upper limit vehicle speed Vup is less than the vehicle speed Vold before the change.

[0072] If the maximum vehicle speed Vup is less than the vehicle speed Vold before the change, the CPU determines "yes" in step 405 and proceeds to step 410. In step 410, the CPU determines whether the driver has performed an acceleration intention operation. In addition, if either the first acceleration intention condition AC1 or the second acceleration intention condition AC2 is met, the CPU determines that the driver has performed an acceleration intention operation.

[0073] If the driver intends to accelerate, the CPU determines "yes" in step 410 and proceeds to step 415. In step 415, the CPU determines that the reset condition is met. Then, the process proceeds to step 495, and the CPU terminates this subroutine. Afterwards, the process continues... Figure 3 Step 345 is shown.

[0074] If the driver does not intend to accelerate, the CPU... Figure 4 If the condition in step 410 is "No", the process proceeds to step 420. In step 420, the CPU determines that the reset condition is not met. Then, the process proceeds to step 495.

[0075] If the upper limit speed Vup is not less than the previous speed Vold when entering step 405 (i.e., the upper limit speed Vup is greater than the previous speed Vold), the CPU determines "No" in step 405 and proceeds to step 425. In step 425, the CPU determines whether the driver has attempted to decelerate.

[0076] If either the first deceleration intention condition DC1 or the second deceleration intention condition DC2 is met, it is determined that the driver has performed a deceleration intention operation.

[0077] First deceleration intention condition DC1: Throttle opening AP is reduced by a specified percentage (e.g., 20%) or more from the time of change.

[0078] The second deceleration intention condition DC2: the braking operation amount BP becomes the threshold operation amount BPth or higher.

[0079] If the driver intends to decelerate, the CPU determines "yes" in step 425 and proceeds to step 415. If the driver does not intend to decelerate, the CPU determines "no" in step 425 and proceeds to step 420.

[0080] As explained above, when the upper speed limit Vup is changed, if the driver's operation of the accelerator pedal 28a or brake pedal 30a meets the reset conditions, the upper speed limit Vup is reset to the original speed Volt. Therefore, when the upper speed limit Vup is changed to "the incorrectly identified speed limit Vlmt", the upper speed limit Vup can be corrected with an operation that is less likely to be cumbersome for the driver.

[0081] (Example 1)

[0082] If at least one of the following conditions is met: the throttle opening AP is greater than or equal to the threshold opening APth, or the rate of change of the throttle opening AP is greater than or equal to the threshold rate of change, the CPU can determine that the acceleration intention condition is met. Additionally, the threshold opening APth is sometimes referred to as the threshold acceleration operation amount.

[0083] The CPU can determine that the deceleration intention condition is met if at least one of the following conditions is met: the braking operation amount BP is greater than or equal to the threshold operation amount BPth; or the rate of change of the braking operation amount BP per specified unit time is greater than or equal to the specified threshold rate of change. Additionally, the threshold operation amount BPth is sometimes referred to as the threshold deceleration operation amount.

[0084] (Second variation)

[0085] In the above embodiments, the speed limit Vlmt is identified based on image data, but it is not limited to this. For example, the CPU can refer to map data that records the speed limits Vlmt for roads to identify the speed limit Vlmt for the current position of vehicle VA.

[0086] (3rd variation)

[0087] Speed ​​limit control can be used to maintain the vehicle speed Vs at the upper limit speed Vup so that the vehicle VA can travel. Even with this type of speed limit control, the vehicle speed Vs can be limited so that it does not exceed the upper limit speed Vup.

[0088] This device 10 is applicable to vehicles such as gasoline vehicles, hybrid vehicles, plug-in hybrid vehicles, fuel cell vehicles, and electric vehicles, and can also be used in autonomous vehicles.

[0089] Symbol Explanation

[0090] 10-Speed ​​limiting device, 28-Throttle opening sensor, 28a-Throttle pedal, 30-Brake operation amount sensor, 30a-Brake pedal, 32-Powertrain actuator, 34-Brake actuator.

Claims

1. A vehicle speed limiting device that performs vehicle speed limiting control to limit the vehicle speed so that the vehicle speed, representing the speed of the vehicle, does not exceed a maximum vehicle speed, characterized in that, The vehicle speed limiting device is configured as follows: If the speed limit of the road on which the vehicle is traveling is re-identified, the upper speed limit will be changed to the speed limit. If, during a specified reset period from the point when the upper limit speed was changed, the driver's operation of the acceleration or deceleration control meets the specified reset conditions, the upper limit speed is reset to the upper limit speed before the change.

2. The vehicle speed limiting device according to claim 1, characterized in that, The vehicle speed limiting device is configured as follows: If the maximum vehicle speed is changed to a lower maximum vehicle speed than before the change, it is determined whether the driver has performed an acceleration intention operation based on the operation of the acceleration control component. If the driver performs the acceleration intention operation, the upper limit speed is reset to the upper limit speed before the change.

3. The vehicle speed limiting device according to claim 2, characterized in that, The vehicle speed limiting device is configured as follows: If at least one of the following conditions is met: the acceleration operation amount representing the amount of operation of the acceleration operation is above a threshold acceleration operation amount, and the rate of change of the amount of operation amount representing the change per specified unit time is above a threshold rate of change, it is determined that the driver has performed the acceleration intention operation.

4. The vehicle speed limiting device according to claim 1, characterized in that, The vehicle speed limiting device is configured as follows: If the maximum vehicle speed is changed to a higher maximum vehicle speed than before the change, it is determined whether the driver has performed a deceleration intention operation based on the operation of the acceleration or deceleration control. If the driver performs the deceleration intention operation, the upper limit speed is reset to the previous upper limit speed.

5. The vehicle speed limiting device according to claim 4, characterized in that, The vehicle speed limiting device is configured as follows: If at least one of the following conditions is met: the deceleration operation amount representing the amount of operation of the deceleration control is greater than or equal to a threshold deceleration operation amount, and the rate of change of the amount of operation amount representing the change per specified unit time is greater than or equal to a threshold rate of change, it is determined that the driver has performed the deceleration intention operation.

Images