Vehicle speed limiter

Abstract

The present invention provides a speed limiting device that allows the driver to correct the upper speed limit with an operation that is unlikely to be bothersome, in the event that the speed limit is incorrectly recognized. [Solution] The vehicle speed limiting device performs vehicle speed limiting control to prevent the vehicle speed from exceeding the upper limit vehicle speed. When the vehicle speed limiting device recognizes a new speed limit on the road on which the vehicle is traveling, it changes the upper limit vehicle speed to the limit vehicle speed. If the driver's operation of the acceleration or deceleration control satisfies predetermined reset conditions during the reset period, which is from the time the upper limit vehicle speed was changed until a predetermined time has elapsed, 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 executes vehicle speed limiting control for limiting the vehicle speed so that the vehicle speed representing the speed of the vehicle does not exceed the upper limit vehicle speed. 【Background Art】 【0002】 Conventionally, a vehicle speed limiting device that executes vehicle speed limiting control for limiting the vehicle speed so that the vehicle does not exceed the speed limit of the road on which the vehicle is traveling is known. For example, the vehicle 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 vehicle speed to that speed limit. The conventional device makes the vehicle travel so that the vehicle speed does not exceed the upper limit vehicle speed and displays the upper limit vehicle speed and the speed limit. In the conventional device, when the driver determines that the speed limit has been erroneously detected, the driver can perform a correction operation on a switch for correcting the upper limit vehicle speed. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Unexamined Patent Application Publication No. 2018-58436 【Summary of the Invention】 【0004】 According to the conventional device, when the speed limit is erroneously recognized (detected), the driver needs to operate a switch. The driver may find such an operation of the switch troublesome. 【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 vehicle speed limiting device that can correct the upper limit vehicle speed by an operation that is less likely to trouble the driver when the speed limit is erroneously recognized. 【0006】 The vehicle speed limiting device of the present invention (hereinafter referred to as "the present invention device") performs vehicle speed limiting control to limit the vehicle speed, which represents the speed of the vehicle, so as not to exceed the upper limit vehicle speed. The aforementioned vehicle speed limiting device is If a new speed limit is recognized on the road on which the vehicle is traveling (step 310 "Yes"), the upper speed limit is changed to the speed limit (step 335), If, during the reset period from the time the upper limit speed was changed until a predetermined time has elapsed, the driver's operation of the acceleration or deceleration control satisfies the predetermined reset conditions (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). It is structured in this way. 【0007】 This allows the driver to set the upper speed limit back to the previous speed limit simply by operating the acceleration or deceleration controls if the speed limit is misrecognized. Therefore, the speed limit can be corrected with an operation that is less likely to be perceived as cumbersome by the driver. [Brief explanation of the drawing] 【0008】 [Figure 1] This is a schematic system configuration diagram of a vehicle speed limiting device according to an embodiment of the present invention. [Figure 2] This is a timing chart of vehicle speed, accelerator opening, and braking force to illustrate an example of operation of a vehicle speed limiting device according to an embodiment of the present invention. [Figure 3] Figure 1 is a flowchart of the upper limit vehicle speed setting routine executed by the ECU's CPU. [Figure 4] Figure 1 is a flowchart of the reset condition determination subroutine executed by the ECU's CPU. [Modes for carrying out the invention] 【0009】 A vehicle speed limiting 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 photographing the scenery in front of the vehicle VA. ECU 20 acquires the image data from camera 22 and recognizes the speed limit Vlmt of the road on which the vehicle VA is traveling based on the image data. 【0011】 The vehicle speed sensor 24 measures the vehicle speed Vs, which represents the speed of the vehicle VA. The acceleration sensor 26 measures the longitudinal acceleration G of the vehicle VA. The accelerator pedal position sensor 28 measures the accelerator pedal position AP, which represents the amount of depression (operation) of the accelerator pedal (acceleration operator) 28a. Note that accelerator pedal position AP is sometimes referred to as "acceleration operation amount". The brake operation amount sensor 30 measures the brake operation amount BP, which represents the amount of depression (operation) of the brake pedal (deceleration operator) 30a. Brake operation amount BP is sometimes referred to as "deceleration operation amount". The ECU 20 acquires the measured values ​​from these sensors 26 to 32. 【0012】 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. 【0013】 <Vehicle speed limit control> The ECU20 performs speed limit control to restrict the vehicle speed Vs so that it does not exceed the upper limit vehicle speed Vup. Based on image data, the ECU20 detects speed limit signs and road markings, etc., and recognizes the speed limit Vlmt indicated by the speed limit signs and road markings, etc. The ECU20 sets the recognized speed limit Vlmt as the upper limit vehicle speed Vup. 【0014】 The ECU20 obtains the limiting acceleration Gtgt to match the vehicle speed Vs with the upper limit vehicle speed Vup. The ECU20 also obtains the limiting braking force Flmt required for the acceleration G to match the limiting acceleration Gtgt. The ECU20 then obtains the smaller of the following two braking forces as the target braking force Ftgt: "driver-requested braking force Freq according to accelerator opening AP or brake operation amount BP" and the limiting braking force Flmt. 【0015】 The target braking force Ftgt can be a positive or negative value. If the target braking force Ftgt is a positive value, the ECU 20 applies a driving force to the vehicle VA. Specifically, the ECU 20 controls the powertrain actuator 32 so that the driving force matches the positive target braking force Ftgt. On the other hand, if the target braking force Ftgt is a negative value, the ECU 20 applies a braking force to the vehicle VA. Specifically, the ECU 20 controls the powertrain actuator 32 and the brake actuator 34 so that the braking force matches the negative target braking force Ftgt. 【0016】 When the driver depresses the accelerator pedal 28a, the driver-requested driving force Freq becomes a positive value. The larger the accelerator pedal opening AP, the larger the driver-requested driving force Freq becomes. When the driver depresses the brake pedal 30a, the driver-requested driving force Freq becomes a negative value. The larger the brake operation amount BP, the smaller the driver-requested driving force Freq becomes. 【0017】 (Summary of operation) When the ECU 20 newly recognizes the restricted vehicle speed Vlmt, it changes the upper limit vehicle speed Vup to the "newly recognized restricted vehicle speed Vlmt". When the operation of the accelerator pedal 28a or the brake pedal 30a satisfies the reset condition during the reset period from the time point of changing the upper limit vehicle speed Vup (refer to t4 in Fig. 2) to the time point when the reset time Tres has elapsed since the change time point, the ECU 20 resets the upper limit vehicle speed Vup to the restricted vehicle speed Vlmt (previous vehicle speed Vold) before the change. 【0018】 When the upper limit vehicle speed Vup is set to the "misrecognized restricted vehicle speed Vlmt", the driver can return the upper limit vehicle speed Vup to its original state by operating the accelerator pedal 28a or the brake pedal 30a. It is less likely that the driver will find the operation of the accelerator pedal 28a or the brake pedal 30a troublesome. Therefore, when the upper limit vehicle speed Vup is changed to the "misrecognized restricted vehicle speed Vlmt", the upper limit vehicle speed Vup can be corrected by an operation that is less likely to trouble the driver. 【0019】 Furthermore, when the upper limit vehicle speed Vup is changed so as to be lower than the previous vehicle speed Vold, when the operation of the accelerator pedal 28a is an "acceleration intention operation indicating the driver's intention to accelerate", the ECU 20 resets the upper limit vehicle speed Vup to the previous vehicle speed Vold. 【0020】 When the restricted vehicle speed Vlmt is misrecognized to be lower than the true restricted vehicle speed Vlmt, the upper limit vehicle speed Vup becomes lower than the previous vehicle speed Vold. In this case, the vehicle VA decelerates so that the vehicle speed Vs matches the "misrecognized restricted vehicle speed Vlmt". Therefore, the driver operates the accelerator pedal 28a to accelerate the vehicle VA so that the vehicle speed Vs matches the true restricted vehicle speed Vlmt (with an intention to accelerate). Therefore, as described above, when the operation of the accelerator pedal 28a is an acceleration intention operation, the upper limit vehicle speed Vup is reset to the previous vehicle speed Vold, so it is possible to reduce the likelihood that the driver will find the operation for correcting the upper limit vehicle speed Vup troublesome. 【0021】 Furthermore, when the upper limit vehicle speed Vup is changed to be higher than the previous vehicle speed Vold, if the operation of the accelerator pedal 28a or the brake pedal 30a is a "deceleration intention operation representing the driver's deceleration intention", the ECU 20 resets the upper limit vehicle speed Vup to the previous vehicle speed Vold. 【0022】 When the restricted vehicle speed Vlmt is erroneously recognized to be higher than the true restricted vehicle speed Vlmt, the upper limit vehicle speed Vup becomes higher than the previous vehicle speed Vold. In this case, the vehicle VA accelerates so that the vehicle speed Vs matches the "erroneously recognized restricted vehicle speed Vlmt". Therefore, the driver operates the accelerator pedal 28a or the brake pedal 30a (with the intention of decelerating) to decelerate the vehicle VA so that the vehicle speed Vs matches the true restricted vehicle speed Vlmt. Accordingly, when the upper limit vehicle speed Vup is reset to the previous vehicle speed Vold when the operation of the accelerator pedal 28a or the brake pedal 30a is a deceleration intention operation as described above, the driver is less likely to feel bothered by the operation for correcting the upper limit vehicle speed Vup. 【0023】 (Operation example) Referring to FIG. 2, an operation example of the present device 10 will be described. At time t1, the driver depresses the accelerator pedal 28a until the accelerator opening AP becomes "70%". Therefore, the driver required driving force Freq increases. At time t1, the upper limit vehicle speed Vup is set to "50 km / h" and the vehicle speed Vs is sufficiently lower than the upper limit vehicle speed Vup. Therefore, the restricted driving force Flmt is greater than the driver required driving force Freq. Thus, the target driving force Ftgt is set to the driver required driving force Freq, and after time t1, the vehicle speed Vs increases. 【0024】 After that, when the vehicle speed Vs approaches the upper limit vehicle speed Vup, the restricted driving force Flmt becomes smaller than the driver required driving force Freq. At time t2, the vehicle speed Vs matches the upper limit vehicle speed Vup ("50 km / h"). After time t2, although the driver depresses the accelerator pedal 28a, the vehicle VA travels while maintaining the vehicle speed Vs at "50 km / h". 【0025】 At time t3, the speed limit Vlmt ("70km / h") is newly recognized, and the upper speed limit Vup is set to "70km / h". The speed limit Flmt increases and eventually matches the driver-requested speed Freq. The vehicle speed Vs increases from "50km / h" and eventually matches "70km / h". From the point when the vehicle speed Vs matches "70km / h", the vehicle VA travels at "70km / h". 【0026】 Subsequently, at time t4, a new speed limit Vlmt ("30km / h") is recognized, and the upper speed limit Vup is set to "30km / h". In other words, the upper speed limit Vup is changed to be less than the pre-change speed Vold (70km / h). In this case, the limiting driving force Flmt becomes a negative value, and the vehicle VA begins to decelerate. However, this speed limit Vlmt ("30km / h") is incorrectly recognized. Therefore, the driver presses the accelerator pedal 28a in an attempt to accelerate the vehicle VA. At time t5, this operation of the accelerator pedal 28a is determined to be an intended acceleration operation, and the upper speed limit Vup is changed back to the pre-change speed Vold (70km / h). Note that time t5 falls within the period from the time of the change in upper speed limit Vup (t4) to time t6, after the reset time Tres has elapsed. 【0027】 Furthermore, if either of the following first acceleration intention condition AC1 or second acceleration intention condition AC2 is met, the operation of the accelerator pedal 28a is determined to be an operation with the intention of acceleration. 【0028】 The first acceleration intention condition AC1 is met when both of the following conditions AC1a and AC1b are satisfied. Condition AC1a: The accelerator opening (AP) has increased by a predetermined percentage (e.g., 20%) or more since the time of the change. Condition AC1b: The rate of change of the accelerator pedal position AP during the period from the time of change until it increases by a predetermined percentage or more is greater than or equal to a predetermined threshold rate of change. The rate of change represents the amount of change in the accelerator opening (AP) per given unit time. 【0029】 The second acceleration intention condition AC2 is met when both of the following conditions AC2a and AC2b are satisfied. Condition AC2a: The accelerator opening degree AP at the time of the change is less than the threshold opening degree APth (e.g., 90%), and the accelerator opening degree AP becomes equal to or greater than the threshold opening degree APth within a predetermined time from the time of the change. Condition AC2b: The rate of change of the accelerator opening AP during the period from the time of change until it reaches or exceeds the threshold opening APth is greater than or equal to a predetermined threshold rate of change. 【0030】 As shown in Figure 2, the second acceleration intention condition is met at time t5. This means that if the upper limit vehicle speed Vup is changed to be less than the pre-change vehicle speed Vold (70 km / h), the upper limit vehicle speed Vup will be changed back to the pre-change vehicle speed Vold based on the operation of the accelerator pedal 28a. Therefore, the likelihood of the driver finding the operation required to change the upper limit vehicle speed Vup cumbersome can be reduced. 【0031】 (Specific operation) <Upper Speed ​​Limit Setting Routine> The CPU of ECU20 executes the upper limit vehicle speed setting routine, as shown in the flowchart in Figure 3, at predetermined intervals. When the appropriate time arrives, the CPU executes steps 300 and 310 in Figure 3. 【0032】 Step 305: The CPU acquires image data from camera 22. Step 310: The CPU determines whether or not it has newly recognized a speed limit Vlmt. 【0033】 If no new speed limit Vlmt is recognized, the CPU determines "No" in step 310, and the process proceeds to step 315. In step 315, the CPU determines whether the reset flag Xres is "1". The reset flag Xres is set to "1" if it is the reset period, and to "0" if it is not the reset period. The execution flag Xexe is set to "0" in the initialization routine. The initialization routine is executed by the CPU when the ignition key switch (not shown) of the vehicle VA is changed from the off position to the on position. 【0034】 If the reset flag Xres is "0", the CPU determines "No" in step 315, and the process proceeds to step 395. In step 395, the CPU terminates this routine. 【0035】 If a new speed limit Vlmt is recognized when the process proceeds to step 310, the CPU determines "Yes" in step 310, and the process proceeds to step 320. In step 320, the CPU determines whether the upper speed limit Vup is the same as the newly recognized speed limit Vlmt. In other words, the CPU determines whether the newly recognized speed limit Vlmt is the same as the previously recognized speed limit Vlmt. 【0036】 If the upper limit vehicle speed Vup is different from the newly recognized limit vehicle speed Vlmt, the CPU determines "No" in step 320 and executes steps 325 to 345. Step 325: The CPU sets the reset flag Xres to "1" and Timer T to "0". Timer T is a timer used to count the elapsed time since the change in the upper speed limit Vup. Step 330: The CPU sets the pre-change vehicle speed Vold to the current upper limit vehicle speed Vup. Step 335: The CPU sets the upper speed limit Vup to the newly recognized speed limit Vlmt. In other words, the CPU overwrites the upper speed limit Vup with the newly recognized speed limit Vlmt. Step 340: The CPU executes a reset condition determination subroutine to determine whether the reset conditions have been met. Details of the reset condition determination subroutine will be described later. Step 345: The CPU determines whether the reset conditions have been met. 【0037】 If the reset conditions are not met, the CPU determines "No" in step 345, and the process proceeds to step 395. 【0038】 If the reset flag Xres is "1" when the process proceeds to step 315, the CPU determines "Yes" in step 315 and executes steps 350 and 355. 【0039】 Step 350: The CPU adds "1" to Timer T. Step 355: The CPU determines whether Timer T is equal to or greater than a predetermined threshold Tth. When Timer T reaches the threshold Tth, the threshold Tth is set so that a reset time Tres elapses from the time the upper limit vehicle speed Vup is changed. 【0040】 If timer T is less than the threshold Tth, the CPU determines "No" in step 355, and the process proceeds to step 340. 【0041】 If the reset condition is met when the process proceeds to step 345, the CPU determines "Yes" in step 345 and executes steps 360 and 365. Step 360: The CPU changes the upper limit vehicle speed Vup to the previous vehicle speed Vold. Step 365: The CPU sets the reset flag Xres to "0" and sets Timer T to "0". The process then proceeds to step 395. 【0042】 On the other hand, if the timer T is greater than or equal to the threshold Tth when the process proceeds to step 355, the CPU determines "Yes" in step 355, and the process proceeds to step 365. 【0043】 <Subroutine for determining reset conditions> When the process proceeds to step 340, the CPU starts processing from step 400 as shown in Figure 4, and the process proceeds to step 405. In step 405, the CPU determines whether the upper limit vehicle speed Vup is less than the pre-change vehicle speed Vold. 【0044】 If the upper limit vehicle speed Vup is less than the pre-change vehicle speed Vold, the CPU determines "Yes" in step 405, and the process proceeds to step 410. In step 410, the CPU determines whether the driver performed an acceleration intention operation. If either of the first acceleration intention condition AC1 or the second acceleration intention condition AC2 is met, the CPU determines that the driver performed an acceleration intention operation. 【0045】 If the driver intends to accelerate, the CPU determines "Yes" in step 410, and the process proceeds to step 415. In step 415, the CPU determines that the reset condition has been met. The process then proceeds to step 495, and the CPU terminates this subroutine. The process then proceeds to step 345 as shown in Figure 3. 【0046】 If the driver does not intend to accelerate, the CPU determines "No" in step 410 as shown in Figure 4, and the process proceeds to step 420. In step 420, the CPU determines that the reset condition is not met. The process then proceeds to step 495. 【0047】 If, when the process proceeds to step 405, the upper limit vehicle speed Vup is not less than the pre-change vehicle speed Vold (i.e., the upper limit vehicle speed Vup is greater than the pre-change vehicle speed Vold), the CPU determines "No" in step 405, and the process proceeds to step 425. In step 425, the CPU determines whether the driver performed an action with the intention of decelerating. 【0048】 If either of the following first deceleration intention conditions DC1 or second deceleration intention conditions DC2 is met, it is determined that the driver performed an operation with the intention of decelerating. First deceleration intention condition DC1: The accelerator opening AP decreases by a predetermined percentage (e.g., 20%) or more from the time of the change. Second acceleration intention condition AC2: The brake operation amount BP becomes equal to or greater than the threshold operation amount BPth. 【0049】 If the driver intends to decelerate, the CPU determines "Yes" in step 425, and the process proceeds to step 415. If the driver does not intend to decelerate, the CPU determines "No" in step 425, and the process proceeds to step 420. 【0050】 As explained above, when the upper limit speed Vup is changed, if the driver operates the accelerator pedal 28a or brake pedal 30a and the reset conditions are met, the upper limit speed Vup will be reset to the previous speed Vold. This allows the upper limit speed Vup to be corrected with an operation that is less likely to be bothersome to the driver if it has been changed to the "mistakenly recognized upper limit speed Vlmt". 【0051】 (First variation) The CPU may determine that the acceleration intention condition has been met if at least one of the following conditions is met: the accelerator opening degree AP is greater than or equal to the threshold opening degree APth, and the rate of change of the accelerator opening degree AP is greater than or equal to the threshold rate of change. The threshold opening degree APth is sometimes referred to as the threshold acceleration operation amount. 【0052】 The CPU may determine that the deceleration intention condition has been met if at least one of the following conditions is met: the brake operation amount BP is equal to or greater than the threshold operation amount BPth, and the rate of change representing the amount of change in the brake operation amount BP per predetermined unit time is equal to or greater than a predetermined threshold rate of change. Note that the threshold operation amount BPth may be referred to as the threshold deceleration operation amount. 【0053】 (Second variation) In the above embodiment, the speed limit Vlmt was recognized based on image data, but this is not limited to that. For example, the CPU may refer to map data in which the speed limits Vlmt of roads are registered and recognize the speed limit Vlmt of the vehicle VA at its current location. 【0054】 (Third variation) The vehicle speed limit control may also be a control that maintains the vehicle speed Vs at the upper limit vehicle speed Vup while driving the vehicle VA. Even with such a vehicle speed limit control, it is possible to limit the vehicle speed Vs so that it does not exceed the upper limit vehicle speed Vup. 【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, and is also applicable to autonomous vehicles. [Explanation of symbols] 【0056】 10...Vehicle speed limiter, 28...Accelerator position sensor, 28a...Accelerator pedal, 30...Brake operation amount sensor, 30a...Brake pedal, 32...Powertrain actuator, 34...Brake actuator.

Claims

[Claim 1] In a vehicle speed limiting device that performs vehicle speed limiting control so that the vehicle speed, which represents the speed of the vehicle, does not exceed the upper limit vehicle speed, The aforementioned vehicle speed limiting device is If the vehicle recognizes a new speed limit on the road it is traveling on, the upper speed limit is changed to the speed limit. If, during the reset period from the time the aforementioned upper speed limit was changed until a predetermined time has elapsed, the driver's operation of the acceleration or deceleration control satisfies the predetermined reset conditions, the aforementioned upper speed limit shall be reset to the upper speed limit before the change. A vehicle speed limiting device configured in such a way. [Claim 2] In the vehicle speed limiting device according to claim 1, The aforementioned vehicle speed limiting device is When the upper limit of vehicle speed is changed to be lower than the upper limit of vehicle speed before the change, it is determined whether the driver performed an acceleration intention operation that indicates an intention to accelerate, based on the operation of the acceleration control device. If the driver performs the acceleration operation, the upper limit of the vehicle speed is reset to the upper limit of the vehicle speed before the change. A vehicle speed limiting device configured in such a way. [Claim 3] In the vehicle speed limiting device according to claim 2, The aforementioned vehicle speed limiting device is The conditions are that the acceleration control amount representing the amount of the acceleration control device is greater than or equal to the threshold acceleration control amount, and The condition is that the rate of change representing the amount of change in the acceleration operation per predetermined unit time is greater than or equal to a threshold rate of change, If at least one of the following is true, The system is configured to determine that the driver performed the acceleration intent operation. Vehicle speed limiter. [Claim 4] In the vehicle speed limiting device according to claim 1, The aforementioned vehicle speed limiting device is When the upper limit of vehicle speed is changed to be greater than the upper limit of vehicle speed before the change, it is determined whether the driver performed a deceleration operation indicating an intention to decelerate, based on the operation of the acceleration control or the deceleration control. If the driver performs the aforementioned deceleration operation, the upper limit of the vehicle speed shall be reset to the upper limit of the vehicle speed before the change. A vehicle speed limiting device configured in such a way. [Claim 5] In the vehicle speed limiting device according to claim 4, The aforementioned vehicle speed limiting device is The conditions are that the amount of deceleration operation representing the amount of operation of the deceleration control unit is equal to or greater than the threshold deceleration operation amount, and This represents the amount of change in the deceleration operation amount per predetermined unit time, provided that it is greater than or equal to a threshold rate of change. If at least one of the following is true, The system is configured to determine that the driver performed the deceleration operation. Vehicle speed limiter.

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