One pedal control device and one pedal control program

Abstract

To provide a one pedal control device and a one pedal control program which reduce frequency correcting brake distance by an operator correcting to step an accelerator pedal during period from accelerator-off to stopping.SOLUTION: A one pedal control device 10 comprises a speed detection part 11 which detects travel speed of a vehicle at accelerator-off time in traveling with prescribed threshold value speed or less, a brake distance calculation part 12 which calculates brake distance from accelerator-off to stopping at target stop position, a deceleration speed setting part 13 which sets target deceleration at accelerator-off time on the basis of travel speed and brake distance and an acceleration and deceleration adjustment part 14 which adjusts acceleration and deceleration on the basis of the target deceleration.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control technique for one-pedal drive, which allows the acceleration and deceleration of a vehicle to be adjusted using only an accelerator pedal. [Background technology]

[0002] Electric vehicles (EVs) are equipped with a one-pedal drive function that allows the vehicle to accelerate and decelerate using only the accelerator pedal. When the vehicle is in one-pedal mode using the one-pedal drive function, if the driver takes his or her foot off the accelerator pedal, the vehicle will decelerate and stop as if the brakes were applied. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-94542 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional technology, if the deceleration during free running after the accelerator is released is stronger than the driver intends, the vehicle will stop before the intended stopping position before depressing the brake pedal. Also, in order to prevent the vehicle from stopping before the intended stopping position when the deceleration is too strong, the driver must adjust the speed by pressing the accelerator pedal and the brake pedal again during deceleration.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a one-pedal control device and a one-pedal control program that reduces the frequency with which a driver must re-press the accelerator pedal to correct the braking distance between releasing the accelerator and stopping the vehicle. [Means for solving the problem]

[0006] The one-pedal control device of this embodiment includes a speed detection unit that detects the vehicle's traveling speed when the accelerator is released while the vehicle is traveling at or below a predetermined threshold speed, a braking distance calculation unit that calculates the braking distance from when the accelerator is released to when the vehicle is stopped at a target stopping position, a deceleration setting unit that sets a target deceleration when the accelerator is released based on the traveling speed and the braking distance, and an acceleration / deceleration adjustment unit that adjusts acceleration / deceleration based on the target deceleration.

[0007] The one-pedal control program of this embodiment causes a computer to execute the steps of detecting the vehicle's traveling speed when the accelerator is released while the vehicle is traveling at or below a predetermined threshold speed, calculating the braking distance from when the accelerator is released until the vehicle stops at a target stopping position, setting a target deceleration when the accelerator is released based on the traveling speed and the braking distance, and adjusting acceleration / deceleration based on the target deceleration. Effect of the Invention

[0008] The present invention provides a one-pedal control device and a one-pedal control program that reduce the frequency with which a driver corrects the braking distance by depressing the accelerator pedal again between releasing the accelerator and stopping the vehicle. [Brief description of the drawings]

[0009] [Figure 1] 1 is a configuration diagram of a vehicle equipped with a one-pedal control device according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a diagram showing the relationship between the travel distance and the travel speed when controlled by the one-pedal control device according to the embodiment of the present invention. [Diagram 3] 4 is a flowchart showing the operation of the one-pedal control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0011] Fig. 1 is a configuration diagram of a vehicle 50 equipped with a one-pedal control device 10 according to an embodiment of the present invention. Fig. 2 is a diagram showing the relationship between the travel distance and the travel speed when controlled by the one-pedal control device 10. In this embodiment, releasing the foot from the accelerator pedal 18a that has been depressed as described above is referred to as "accelerator off."

[0012] As shown in FIG. 1, a one-pedal control device 10 according to the embodiment includes a speed detection unit 11, a braking distance calculation unit 12, a deceleration setting unit 13, and an acceleration / deceleration adjustment unit 14. The functions of the components 11 to 14 of the one-pedal control device 10 are realized, for example, as the functions of an accelerator ECU (Electronic Control Unit) 15 that electronically controls an accelerator system 18.

[0013] Moreover, the one-pedal control device 10 preferably includes a learning unit 16 and a timer 17. The one-pedal control device 10 is connected to an accelerator system 18, a brake pedal 19, a display unit 20, a driving motor 21, and various sensors 22 to 24 via an in-vehicle network 25 of the vehicle 50. The in-vehicle network 25 is configured, for example, by a CAN-FD (Controller Area Network with Flexible Data Rate) bus.

[0014] The speed detection unit 11 acquires information on the wheel speed from, for example, a wheel speed sensor 22, and detects a predetermined threshold speed V 0 The vehicle speed when the accelerator is released during the following driving is detected. Here, the threshold speed V 0 The threshold speed V is a low speed at which the vehicle 50 may stop, for example, about 30 km / h. Hereinafter, the threshold speed V in the one-pedal mode in which the vehicle 50 runs using the one-pedal drive function will be referred to as the threshold speed V. 0 The following driving state is referred to as a “low speed driving state.” The deceleration of the vehicle 50 is detected by, for example, the G sensor 23. Also, whether the accelerator is released is detected by using the accelerator position sensor 24 which detects the position of the accelerator pedal 18a.

[0015] The braking distance calculation unit 12 calculates the braking distance D from when the accelerator is released in a low-speed driving state until the vehicle stops at the target stopping position M. The braking distance D is calculated based on the driving speed at the time the accelerator is released and the time until the vehicle stops. At the time of shipment, the target stopping position M and the braking distance D are set to provisional initial values. As the number of driving sessions increases, machine learning (hereinafter simply referred to as "learning") by the learning unit 16 progresses, and the target stopping position M and the braking distance D are adjusted to the optimum values ​​preferred by the driver.

[0016] The learning unit 16 is equipped with, for example, artificial intelligence, and learns by linking the driving speed when the accelerator is released in a low-speed driving state with the braking distance D, as shown in Fig. 2. By having the learning unit 16 learn only when the vehicle is in a low-speed driving state, the variation in the braking distance D becomes smaller than when learning is performed from a high driving speed range, and the accuracy of the learning can be improved. Specifically, each time the accelerator is released in a low-speed driving state, the actual braking distance D after the accelerator is released is obtained for each driving speed immediately before the accelerator is released.

[0017] For example, 11 reference speeds are set from 10 to 30 km / h in 2 km / h increments. If the driving speed when the accelerator is released is between "reference speed - 1 km / h" or more and less than "reference speed + 1 km / h", the braking distance D for that reference speed is recorded. For each reference speed, the average value of the most recent 50 braking distances D is recorded as the target braking distance D. 1 The purpose of taking the average in this way is to prevent accidents caused by sudden changes in deceleration and braking distance D. The target braking distance D is determined from these average values, and the target braking distance D is set as follows: 1 will change slowly.

[0018] In addition, until 50 data sets are obtained, the initial provisional value is set as the target braking distance D 1 In order to improve the accuracy of the stopping position, the target braking distance D 1 The target braking distance D for the upper and lower reference travel speeds close to that travel speed1 It is preferable to calculate it by linear interpolation.

[0019] In addition, before 50 data sets at the target reference speed are obtained, the target braking distance D is calculated by averaging 50 data sets at a reference speed lower than the target reference speed. 1 is the provisional target braking distance D for the target reference driving speed. 1 In this case, the target braking distance D 1 The target braking distance D for a reference speed lower than the provisional value is 1 This is because, from the viewpoint of preventing accidents, it is desirable to set the braking distance D to a short value until the driver has fully learned the optimal braking distance D.

[0020] Returning to FIG. 1, the description of the configuration of the one-pedal control device 10 will continue. The deceleration setting unit 13 sets a target deceleration at the time of releasing the accelerator for each traveling speed based on the traveling speed and the braking distance D at the time of releasing the accelerator in a low-speed traveling state. 1 Immediately after the vehicle 50 is shipped, an initial provisional value is used for the braking distance D to set the target deceleration. After the learning by the learning unit 16 has progressed sufficiently, the target braking distance D learned by the learning unit 16 is set to a value that satisfies the following formula: 1 The target deceleration is set based on the above.

[0021] The acceleration / deceleration adjustment unit 14 adjusts the acceleration / deceleration of the vehicle 50 by controlling the travel motor 21 based on the target deceleration set by the deceleration setting unit 13. The acceleration / deceleration adjustment unit 14 adjusts the acceleration / deceleration so that the vehicle stops at the braking distance D learned by the learning unit 16 without operating the accelerator pedal 18a and the brake pedal 19 when the accelerator is released. In particular, as the learning by the learning unit 16 progresses, it becomes possible to stop the vehicle at the stopping position intended by the driver without the driver performing any operation. This makes it possible to prevent the driver from feeling annoyed.

[0022] In addition, because the control by the acceleration / deceleration adjustment unit 14 is limited to a low-speed driving state, the speed variation at the start of the control can be made smaller than when decelerating from a medium or high speed driving state. Also, if the driving speed is set to zero as the timing when the acceleration / deceleration adjustment unit 14 ends the control, the variation in the speed used in the learning can be further reduced compared to when the control ends when the brake is applied. Therefore, the variation in the braking distance D can be reduced.

[0023] However, even if the accelerator is released during low-speed driving, this may not be a deceleration operation intended to stop the vehicle. In this case, the vehicle 50 does not stop even after a predetermined time has passed since the accelerator was released. If data obtained about such an accelerator release is used for learning by the learning unit 16, the accuracy of the learning will actually decrease. Therefore, it is desirable to use the timer 17 to measure the elapsed time after the accelerator is released. Then, the predetermined limit time T after the accelerator is released is set to 0. 0 If the vehicle 50 has not stopped even after the time limit T has elapsed, it is preferable that the learning unit 16 excludes the data of the traveling speed and the braking distance D obtained when the accelerator is released from the learning data. 0 For example, the time limit T 0 The learning unit 16 sets a time limit T 0 By not learning from data regarding accelerator release when the vehicle 50 does not stop within the designated time, the vehicle 50 can be stopped in a more comfortable and less cumbersome manner for the driver.

[0024] In addition, the learning unit 16 detects a predetermined exclusion time T 1If the accelerator pedal 18a is depressed again within 10 seconds, it is preferable not to perform learning related to the second and subsequent accelerator releases. In other words, in this case, it is preferable to exclude from the learning data the data on the relationship between the driving speed and the braking distance D obtained from the second and subsequent accelerator releases. This is because the second and subsequent accelerator releases are highly likely to be braking correction operations by the driver, and using such data for learning by the learning unit 16 may reduce the accuracy of the learning. In this way, by excluding data related to the second and subsequent accelerator releases from the learning data, the accuracy of the learning can be improved, and the vehicle 50 can be stopped in a more comfortable and less cumbersome manner for the driver. Note that the exclusion time T after the accelerator is released is set to 0.5 seconds. 1 For example, this is 2 seconds.

[0025] Next, the control for suppressing a sudden deceleration sensation will be described. When the vehicle 50 suddenly decelerates and stops, passengers including the driver may feel uneasy. Research on the sudden deceleration of the vehicle 50 and the uneasiness felt by passengers has shown that when the vehicle is traveling at a speed of 30 km / h, the driver feels uneasy when the deceleration is about 2.25 m / s 2 The results showed that many people felt uneasy when the deceleration was about 1.25 m / s 2 The results showed that many people feel safe when the speed is about 1.75 m / s. 2 In this way, passengers feel uneasy when driving due to the balance between the driving speed and deceleration.

[0026] Therefore, in order to reduce the feeling of sudden stopping when the vehicle is stopped, it is desirable for the deceleration setting unit 13 and the acceleration / deceleration adjustment unit 14 to perform control to suppress the feeling of sudden deceleration. A sudden stop occurs when the braking distance D is short compared to the traveling speed when the accelerator is released. As a control method for this, for example, the following two patterns, Control 1 and Control 2, are considered.

[0027] [Control 1. Focus on deceleration] In the control 1 pattern, attention is paid to the deceleration from when the accelerator is released until the vehicle stops. If this deceleration exceeds a predetermined deceleration B, this deceleration is changed to the predetermined deceleration B. Specifically, the predetermined deceleration B is set to 1.75 m / s 2 To explain it this way, the deceleration from when you release the accelerator to when you stop is 1.75m / s 2 If it exceeds this limit, the deceleration is increased to 1.75 m / s 2 This means changing it to.

[0028] In this case, simply releasing the accelerator will cause the vehicle to pass the target stopping position M intended by the driver. Therefore, in this case, the driver is made to operate the brake pedal 19 to stop the vehicle, thereby reducing the anxiety felt by the driver due to sudden deceleration. This is because the driver does not feel anxious even if the deceleration is strong if the driver applies the brakes himself. For example, an alert encouraging braking can be displayed on the display unit 20 to encourage the driver to apply the brakes. In this way, the deceleration and stopping by the acceleration / deceleration adjustment unit 14 are made gradual, thereby reducing the anxiety felt by the driver due to sudden deceleration and stopping.

[0029] [Control 2. Focus on driving speed] In the control pattern 2, the deceleration from the time the accelerator is released until the vehicle stops is constant, and the stopping time T 2 (Hereinafter referred to as “Reference time T 2 The reference time T 2 The running speed in front is a given speed V 1 (Hereinafter referred to as “Reference speed V 1 If it is predicted that the time from the accelerator release to the stop is longer than the reference time T 2 The running speed in front is a given speed V 1 In this manner, the deceleration setting unit 13 changes the deceleration so that the reference time T 2 Before the reference speed V 1 The target deceleration is adjusted and set so that the reference time for stopping T 2 After reaching the target deceleration, the predetermined target deceleration is reset.

[0030] Specifically, the reference time T 2 for 1.5 seconds, and the reference speed V 1 If the deceleration is 1.5 seconds before stopping, and the speed is predicted to exceed 7km / h, the deceleration is changed from when the accelerator is released until 1.5 seconds before stopping so that the speed 1.5 seconds before stopping is 7km / h. And if the deceleration 1.5 seconds before stopping is 1.3m / s 2 The control is performed so that

[0031] Deceleration from when the accelerator is released until 1.5 seconds before the vehicle stops is 1.75 m / s 2 According to the above-mentioned research results, if the deceleration exceeds 1.75 m / s, it is expected that some passengers will feel uneasy while driving. 2 If the deceleration setting unit 13 and the acceleration / deceleration adjustment unit 14 exceed the threshold value, the deceleration setting unit 13 and the acceleration / deceleration adjustment unit 14 perform control by giving priority to the mode of control 1. In other words, the deceleration from the time the accelerator is released until the vehicle is stopped is set to 1.75 m / s without controlling the traveling speed to 7 km / h 1.5 seconds before the vehicle is stopped. 2 The control is based on the priority of becoming.

[0032] In this case, similar to the pattern of control 1, simply releasing the accelerator will cause the vehicle to pass the target stopping position M intended by the driver. Therefore, in this case as well, the driver is required to operate the brake pedal 19 to stop the vehicle, thereby reducing the anxiety felt by the driver due to sudden deceleration.

[0033] An example of braking the vehicle 50 is an Advanced Emergency Braking System (AEBS) that is activated on behalf of the driver when it is determined that a rear-end collision or collision with a preceding vehicle or an obstacle ahead is unavoidable. It is preferable to give priority to braking by the AEBS over braking by the one-pedal control device 10. By giving priority to braking by the AEBS over braking by the one-pedal control device 10, driving safety is improved. In addition, the target braking distance D is calculated by using map information, road gradient information, etc.1 By additionally correcting the target deceleration, the accuracy of the target stopping position M can be further improved.

[0034] Each component of the one-pedal control device 10 can be configured as a computer having a processor such as a CPU, and a storage device such as a Read Only Memory (ROM), a Random Access Memory (RAM), or a Hard Disk Drive (HD). Moreover, instead of such software processing, it can also be realized by hardware such as an ASIC (Application Specific Integration Circuit) or an FPGA (Field-Programmable Gate Array).

[0035] Next, the operation of the one-pedal control device 10 will be described with reference to the flow chart of Fig. 3. In the following, step S10 will be abbreviated to "S10." Similarly, steps S11 and after will also be abbreviated.

[0036] First, the one-pedal control of the vehicle 50 by the one-pedal control device 10 is not executed unless the one-pedal mode is on (if NO in S10, proceed to S11 and END). This is because the one-pedal control of the vehicle 50 is executed during the one-pedal mode.

[0037] If the one-pedal mode is on, the operation further branches depending on whether the vehicle 50 is in a low-speed traveling state (if YES in S10, proceed to S12). If the vehicle 50 is not in a low-speed traveling state, the one-pedal control by the one-pedal control device 10 is not performed (if NO in S12, proceed to S11 and END). The one-pedal control of the vehicle 50 is a control for stopping the vehicle 50, so performing the one-pedal control even when the vehicle is traveling at a medium or high speed and there is no intention to stop the vehicle 50 would be a hindrance to driving.

[0038] When the vehicle 50 is traveling at a low speed, the operation branches depending on whether or not it is detected that the driver has released the accelerator (if YES in S12, proceed to S13). If accelerator release is not detected, one-pedal control of the vehicle 50 is not performed by the one-pedal control device 10 (if NO in S13, proceed to S11 and END). When the accelerator is released, the time elapsed from the previous accelerator release to the current accelerator release is the time limit T 0 The operation branches depending on whether it is equal to or greater than this (if YES in S13, proceed to S14).

[0039] The time elapsed from the last accelerator release to the current accelerator release is the time limit T 0 If it is greater than the limit time T 0 If it is smaller, the data of the driving speed and the braking distance D obtained from the current accelerator release are not included in the learning data by the learning unit 16 (if NO in S14, proceed to S16). 0 This is because if the accelerator is released two or more times within a certain period, the second or subsequent release of the accelerator is likely to be a braking correction operation by the driver.

[0040] Then, braking control is started (S16). If there are 50 or more pieces of braking distance data, the target braking distance D is calculated from the most recent 50 pieces of braking distance D data. 1 (If YES in S17, proceed to S18). 1 is the target braking distance D at the reference driving speed 1 The target braking distance D 1 A target deceleration is set based on the running speed when the accelerator is released (S19). If there are less than 50 braking distance data, the target braking distance D 1(If NO in S17, proceed to S20). Then, the target braking distance D 1 The target deceleration is set based on the initial provisional value set as above and the running speed when the accelerator is released (S19). 1 is the target braking distance D at the reference driving speed 1 It is calculated by linear interpolation.

[0041] If a sudden stop is not predicted, the target deceleration is set normally (if NO in S21, proceed to S22). On the other hand, if a sudden stop is predicted, the deceleration setting unit 13 resets the target deceleration according to, for example, the above-mentioned control 1 or control 2 pattern (if YES in S21, proceed to S23).

[0042] Time limit T from accelerator release 0 If the time has elapsed, the one-pedal control of the vehicle 50 by the one-pedal control device 10 is not performed (if YES in S24, proceed to S11 and END). On the other hand, the time limit T 0 If the time has not elapsed, the braking distance is accumulated for each reference vehicle speed and the operation is terminated (if NO in S24, the process proceeds to S25 and ends).

[0043] As described above, according to the one-pedal control device 10 of the embodiment, in a low-speed driving state, the braking distance D from when the accelerator pedal is released until the vehicle is stopped approaches the driver's intention, and the effort required for the driver to correct the braking distance D by re-depressing the accelerator pedal 18a and the brake 19 is reduced.

[0044] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0045] 10...One-pedal control device, 11...Speed ​​detection unit, 12...Braking distance calculation unit, 13...Deceleration setting unit, 14...Acceleration / deceleration adjustment unit, 15...Accelerator ECU, 16...Learning unit, 17...Timer, 18...Accelerator system, 18a...Accelerator pedal, 19...Brake pedal, 20...Display unit, 21...Travel motor, 22...Wheel speed sensor, 23...G sensor, 24...Accelerator position sensor, 25...In-vehicle network, 50...Vehicle, B...Predetermined deceleration, D...Braking distance, D 1 …Target braking distance D 1 , M...Target stopping position, T 0 …Time limit, T 1 …Exclusion time, T 2 …Reference time (fixed time), V 0 …threshold velocity, V 1 ...Reference speed (predetermined speed).

Claims

1. a speed detection unit that detects a vehicle traveling speed at or below a predetermined threshold speed when the accelerator is released; a braking distance calculation unit that calculates a braking distance from when the accelerator is released until the vehicle stops at a target stopping position; a deceleration setting unit that sets a target deceleration at the time of accelerator release based on the traveling speed and the braking distance; and an acceleration / deceleration adjustment unit that adjusts acceleration / deceleration based on the target deceleration.

2. a learning unit that learns the traveling speed and the braking distance when the accelerator is released in association with each other, 2. The one-pedal control device according to claim 1, wherein the acceleration / deceleration adjustment unit adjusts acceleration / deceleration so that the vehicle stops within the learned braking distance without operating an accelerator pedal and a brake pedal when the accelerator is released.

3. 3. The one-pedal control device according to claim 2, wherein the learning unit does not perform the learning regarding the second or subsequent accelerator releases when the accelerator pedal is depressed again within a predetermined exclusion time after the accelerator release.

4. The one-pedal control device according to claim 2 , wherein the learning unit does not perform the learning if the vehicle has not stopped even after a predetermined time limit has elapsed after the accelerator is released.

5. 3. The one-pedal control device according to claim 2, wherein the deceleration setting unit adjusts and sets the target deceleration so that the vehicle will reach the predetermined speed a certain time before the vehicle reaches the target stopping position when the vehicle's traveling speed is predicted to be equal to or higher than a predetermined speed a certain time before the vehicle reaches the target stopping position, and resets the predetermined target deceleration after the certain time has passed.

6. 3. The one-pedal control device according to claim 2, wherein the deceleration setting unit changes the deceleration to the predetermined deceleration when the driving speed is predicted to be equal to or greater than a predetermined speed a certain time before the target stopping position is reached and the deceleration from the time the accelerator is released until the vehicle stops exceeds the predetermined deceleration.

7. On the computer, Detecting a vehicle speed when the accelerator is released while the vehicle is traveling at or below a predetermined threshold speed; A step of calculating a braking distance from when the accelerator is released until the vehicle stops at a target stopping position; setting a target deceleration at the time of accelerator release based on the traveling speed and the braking distance; A one-pedal control program that executes a step of adjusting acceleration / deceleration based on the target deceleration.

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