JP7351076B2 - Electric vehicle control method and electric vehicle control device - Google Patents

Description

The present invention relates to a method for controlling an electric vehicle including an accelerator pedal whose operation range has a deceleration region and an acceleration region, and a control device for an electric vehicle.

In an electric vehicle that includes a motor as a drive source, a control method for an electric vehicle is known in which an acceleration region and a deceleration region are provided in the operation range of one accelerator pedal, and the acceleration and deceleration of the vehicle is controlled according to the operation amount of the pedal. (For example, Patent Document 1). According to this control method, by causing the motor to perform regenerative braking when the amount of operation of the accelerator pedal is small, acceleration and deceleration can be performed mainly using the accelerator pedal.

Japanese Patent Application Publication No. 2006-177442

In the control method for an electric vehicle disclosed in Patent Document 1, the response characteristic of the motor according to the operation amount of the accelerator pedal is higher than that in a control method that involves a general brake operation. Therefore, even if the driver intends to drive at a constant speed, unintended acceleration or deceleration may occur due to variations in the driver's accelerator pedal operation, which may cause the driver to feel uncomfortable. There is.

The present invention has been made with attention to such problems, and provides a control method for an electric vehicle that suppresses acceleration/deceleration that makes the driver feel uncomfortable in an electric vehicle that performs regenerative braking according to the amount of operation of the accelerator pedal. and to provide a control device for an electric vehicle.

The electric vehicle control method of the present invention provides a deceleration region and an acceleration region in the operation range of the accelerator pedal, and performs acceleration/deceleration control according to the operation amount of the accelerator pedal. The control method for an electric vehicle includes a command value calculation step of calculating a torque command value for the motor according to the amount of operation, and a step of calculating a torque command value for the motor according to the amount of operation when the electric vehicle is in a constant speed control state in which the electric vehicle runs at a constant speed. The present invention includes a correction step of correcting the torque command value so as to suppress a change in the speed of the electric vehicle, and a motor control step of controlling the motor based on the torque command value corrected in the correction step.

According to one aspect of the present invention, in an electric vehicle that performs regenerative braking in accordance with the amount of operation of an accelerator pedal, it is possible to suppress acceleration and deceleration that makes a driver feel uncomfortable.

FIG. 1 is a block diagram of a control system according to a first embodiment installed in an electric vehicle. FIG. 2 is a flowchart of constant velocity control. FIG. 3 is a timing chart when constant velocity control is performed. FIG. 4 is a flowchart of constant velocity control according to the second embodiment. FIG. 5 is a flowchart of constant velocity control according to the third embodiment. FIG. 6 is a flowchart of constant velocity control according to the fourth embodiment. FIG. 7 is a timing chart when constant velocity control is performed. FIG. 8 is a flowchart of constant velocity control according to the fifth embodiment. FIG. 9 is a flowchart of constant velocity control according to the sixth embodiment.

Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram for explaining a control system 10 of a first embodiment installed in an electric vehicle.

The control system 10 includes a forward vehicle detection section 1, a navigation device 4, an external communication device 5, a vehicle speed detection sensor 6, an accelerator operation amount detection sensor 7, a drive system 8, and a control section 9. , installed in electric vehicles.

This control system 10 controls the speed of the electric vehicle according to the operation amount A of the accelerator pedal 7A acquired by the accelerator operation amount detection sensor 7. That is, when the accelerator operation amount is in the deceleration region, the drive system 8 generates a regenerative braking force, and when the accelerator operation amount is in the acceleration region, the drive system 8 generates a driving force. The magnitude of the regenerative braking force is preset according to the accelerator operation amount, and is maximum when the accelerator operation amount is zero. Specifically, it corresponds to the operation amount threshold value A _thc for determining between power running and regenerative braking in the drive system 8 . When the operation amount A of the accelerator pedal 7A is larger than the operation amount threshold value A _thc , it is determined that the vehicle is in the acceleration region, power running is performed, and the vehicle speed V is accelerated. When the operation amount A of the accelerator pedal 7A is smaller than the operation amount threshold value A _thc , it is determined that the vehicle is in the deceleration region, and the vehicle speed V is decelerated by regenerative braking.

The forward vehicle detection section 1 is composed of a camera 2 and a radar 3. The camera 2 photographs an area in the direction in which the vehicle is traveling. The radar 3 irradiates the surroundings of the vehicle with, for example, a laser or millimeter wave, and receives the reflected waves. The radar 3 is placed, for example, at the four corners of the vehicle body and at the front of the vehicle body, and based on the received reflected waves, the radar 3 detects the distance to objects around the vehicle, the relative speed between the vehicle and the object, and the direction in which the object is located. Calculate etc. The control unit 9 detects objects (in particular, other vehicles) that are present in front of the vehicle, based on images taken by the camera 2 and positions of objects around the vehicle detected by the radar 3.

The navigation device 4 includes a GPS receiver (not shown) that receives signals from Global Positioning System (GPS) satellites, a storage unit (not shown) that stores map information, and a calculation unit (not shown). The navigation device 4 recognizes the driving position of the own vehicle based on the received GPS signal and map information. The navigation device 4 also sets a travel route to the input destination.

The external communication device 5 is an example of a communication unit, and is a wireless communication device that performs at least one of vehicle-to-vehicle communication and road-to-vehicle communication, and outputs received information to the control unit 9.

Vehicle speed detection sensor 6 measures vehicle speed V. Specifically, for example, the vehicle speed detection sensor 6 determines the vehicle speed V from the rotational speed of the motor included in the drive system 8 and outputs the vehicle speed V to the control unit 9 .

The accelerator operation amount detection sensor 7 detects the operation amount A of the accelerator pedal 7A, and transmits the detected operation amount A to the control unit 9.

The drive system 8 includes a motor as a drive source. Note that the drive system 8 may include a steering system that performs steering operations, a friction brake, and an engine as a drive source other than the motor. The drive system 8 drives the motor based on the torque command value T ^* calculated by the control unit 9, thereby controlling the running state of the vehicle.

The control unit 9 calculates the torque command value T ^* based on the operation amount A of the accelerator pedal 7A acquired by the accelerator operation amount detection sensor 7. In addition to information regarding the surroundings of the own vehicle obtained from the camera 2, the radar 3, the navigation device 4, and the external communication device 5 (hereinafter also simply referred to as "surrounding information"), the control unit 9 receives various types of information (not shown). Information from sensors (vehicle speed sensor, steering sensor, brake sensor, acceleration sensor, etc.) may be read and the torque command value T ^* may be calculated based on this information. In addition, when performing automatic driving, the control unit 9 may control the steering system and the friction brake in the drive system 8 based on the above information.

Note that the control unit 9 is composed of a microcomputer equipped with a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input/output interface (I/O interface). It is also possible to configure the control section 9 with a plurality of microcomputers. By executing the program stored in the control unit 9, the drive system 8 is controlled and the running of the electric vehicle is controlled.

FIG. 2 is a flowchart showing constant velocity control of this embodiment. Note that a method of controlling the vehicle when the driver intends to drive at a constant speed (also referred to as cruising) is referred to as constant speed control.

First, in step S1, the control unit 9 uses a pre-stored map or the like to determine the pre-correction torque command value T ^* according to the operation amount A of the accelerator pedal 7A detected by the accelerator operation amount detection sensor 7. ^* Calculate. Then, the control unit 9 next executes the process of step S2. Step S1 is an example of a command value calculation step.

In step S2, it is determined whether constant velocity control is necessary, and specifically, the processes of step S21 and step S22 are executed.

In step S21, the control unit 9 determines whether or not there is a deceleration factor, which is an event that can reduce the vehicle speed V, in front of the vehicle. If it is determined that there is no deceleration factor (S21: No), the control unit 9 performs the process of step S22. If it is determined that there is a deceleration factor (S22: Yes), the control unit 9 executes the process of S4. Step S21 is an example of a factor determination step.

In step S21, the following judgment is specifically made.

The control section 9 uses an input signal from the forward vehicle detection section 1 to detect whether or not another vehicle exists within a predetermined distance in front of the vehicle. When the control unit 9 detects that another vehicle is present within a predetermined distance, it determines that there is a deceleration factor. If no other vehicle is detected within a predetermined distance, the control unit 9 determines that there is no deceleration factor.

As another determination method, the control unit 9 uses surrounding information received from the navigation device 4 and the external communication device 5 to determine whether there are red lights, stop signs, railroad crossings, toll booths, curves, etc. in front of the vehicle. The presence or absence of a deceleration factor is determined based on the detection result. Further, the control unit 9 calculates the collision time using the current vehicle speed V, the distance to the vehicle in front, and its speed, and if the collision time exceeds the time to collision (TTC), It may be determined that there is no deceleration factor.

Next, in step S22, the control unit 9 determines whether the vehicle is in a constant speed control state in which the driver intends to travel at a constant speed. If it is determined that the vehicle is in a constant velocity control state (S22: Yes), the control unit 9 performs the process of step S3. If it is determined that the vehicle is not in the constant velocity control state (S22: No), the control unit 9 executes the process of step S4. Step S22 is an example of a constant velocity determination step.

In step S22, the following processing is specifically performed.

The control unit 9 determines whether the amount of change ΔA per unit time of the operation amount A of the accelerator pedal 7A input from the accelerator operation amount detection sensor 7 is equal to or less than a threshold value ΔA _th . Note that this amount of change ΔA is assumed to be a positive value regardless of increase or decrease. The threshold value ΔA _th is the maximum value of the amount of change caused by the fluctuation of the user's operation, and is determined experimentally and statistically. When the amount of change ΔA is less than or equal to the threshold value ΔA _th , the control unit 9 determines that the vehicle is in a constant speed control state in which the driver intends to travel at a constant vehicle speed V. Note that the control unit 9 may determine whether the amount of change ΔA per unit time is equal to or less than the threshold value ΔA _th for a longer period than a predetermined time T _A (for example, 10 seconds).

As another determination method, the control unit 9 determines whether the deviation between the vehicle speed V input from the vehicle speed detection sensor 6 and the average vehicle speed or limited vehicle speed is equal to or less than a threshold value V _th that is longer than a predetermined time T _v. do. If this deviation is less than or equal to the threshold value V _th , the control unit 9 determines that the vehicle is in a constant velocity control state. Further, the control unit 9 calculates the acceleration α by differentiating the vehicle speed V input from the vehicle speed detection sensor 6, and determines that the vehicle is in a constant velocity control state when the acceleration α is smaller than the threshold α _th . It's okay. The threshold value α _th is the maximum value of the amount of change caused by the fluctuation of the user's operation, and is determined experimentally and statistically.

In step S3, the control unit 9 sets a gain G by which the pre-correction torque command value T ^** calculated in step S1 is multiplied. The gain G is set so that the torque deviation ΔT between the pre-correction torque command value T ^** and the ideal torque command value _Tid , which is the torque command value in an ideal constant velocity control state, is small. The ideal torque command value T _id only needs to have a suppressed amount of change, and may be a constant value, for example, or may be a moving average of the pre-correction torque command value T ^** over the past 30 seconds.

When the pre-correction torque command value T ^** is larger than the ideal torque command value _Tid , a gain G smaller than 1 is set. If the pre-correction torque command value T ^** is smaller than the ideal torque command value _Tid , a gain G larger than 1 is set. By doing so, the pre-correction torque command value T ^** approaches the ideal torque command value T _id , its fluctuation is suppressed, and the torque deviation ΔT becomes small. Note that details of this operation will be explained later with reference to FIG. 3.

On the other hand, in step S4, the control unit 9 sets the gain G to 1.

In step S5, the control unit 9 calculates the torque command value T ^* indicating the required driving force by multiplying the pre-correction torque command value T ^** by the gain G. If there is an event that changes the vehicle speed V (S21: Yes) or if the driver does not intend to drive at a constant speed (S22: No), the gain G is set to 1 in step S4. The torque command value T ^* matches the pre-correction torque command value T ^** . Note that the processing in steps S3 and S5 is an example of a correction step.

In step S6, the control unit 9 drives the motor of the drive system 8 based on the torque command value T ^* calculated in step S5. Note that step S6 is an example of a motor control step.

FIG. 3 is a timing chart of the state of the vehicle when the constant velocity control of this embodiment is performed. 3(A) shows the vehicle speed V, FIG. 3(B) shows the torque command value T ^* , and FIG. 3(C) shows the operation amount A of the accelerator pedal 7A. FIG. 3(D) shows the determination result in determining whether the driver intends to perform constant velocity control (S2). In addition, in FIG. 3(D), when it is determined that there is an intention to perform constant velocity control, the level is high, and when it is determined that there is no intention, the level is low.

Moreover, in these figures, the ideal value of each parameter is shown by the broken line, and the value in this embodiment is shown by the solid line. A comparative example in which the constant velocity control of this embodiment is not performed is shown by a dashed line.

As shown in FIG. 3(D), it is at a high level from time t0 to t5, and it is determined that the intention is to perform constant velocity control.

In FIG. 3C, as shown by the dashed line, the operation amount A of the accelerator pedal 7A repeats slight increases and decreases between times t0 and t5 due to variations in the driver's operations. Furthermore, the dashed line indicates the ideal operation amount A _id of the accelerator pedal 7A, which is ideally a constant value. Here, when regenerative braking is performed according to the operation amount A of the accelerator pedal 7A, since the sensitivity of the pre-correction torque command value T ^** to the operation amount A is high, fluctuations may occur in the operation amount A. There is a possibility that the vehicle speed V changes significantly.

In FIG. 3(B), an ideal torque command value T _id , which is a torque command value at which ideal constant velocity control is performed, is shown by a broken line. Furthermore, the dashed line indicates the pre-correction torque command value T ^** , which is the torque command value corresponding to the manipulated variable A in FIG. 3(C) and is calculated in step S1.

At times t0 to t1, t2 to t3, and t4 to t5, the pre-correction torque command value T ^** is larger than the ideal torque command value T _id . Therefore, in step S3, the control unit 9 sets the gain G to a value smaller than 1. Therefore, the torque command value T ^* calculated by multiplying by the gain G becomes smaller than the pre-correction torque command value T ^** .

During times t1 to t2 and t3 to t4, the pre-correction torque command value T ^** is smaller than the ideal torque command value T _id . Therefore, in step S3, the control unit 9 sets the gain G to a value larger than 1. Therefore, the torque command value T ^* becomes larger than the pre-correction torque command value T ^** .

In FIG. 3(A), the ideal vehicle speed V _id , which is ideally constant, is shown by a broken line. Further, a dashed line indicates a pre-correction vehicle speed V ^** corresponding to the pre-correction torque command value T ^** in FIG. 3(B).

Furthermore, the solid line indicates the corrected torque command value T ^* and the corresponding vehicle speed V. Fluctuations in this vehicle speed V are suppressed when compared with the pre-correction vehicle speed V ^** corresponding to the pre-correction torque command value T ^** .

According to the first embodiment configured in this way, the following effects can be obtained.

According to the vehicle control method of the first embodiment, in the constant velocity determination step of step S22, the control unit 9 determines whether the vehicle is in a constant velocity control state where the driver intends to control the vehicle at a constant speed. Determine. If it is determined in the constant velocity determination step of step S22 that the vehicle is in the constant velocity control state (S22: Yes), the control unit 9 controls the vehicle speed V so that the change in vehicle speed V is suppressed in steps S3 and S5. The corrected torque command value T ^* is obtained, and the drive system 8 is controlled using the torque command value T ^* in the motor control step of step S6.

Here, when the motor of the drive system 8 performs regenerative braking in response to the operation amount A of the accelerator pedal 7A, the responsiveness of the torque command value T ^* to the operation amount A is high. Therefore, the torque command value T ^* may increase or decrease due to variations in the operation of the accelerator pedal 7A by the driver, and there is a possibility that acceleration/deceleration that is not intended by the driver may occur. In this embodiment, by providing a correction step for the gain G that suppresses changes in the speed of the vehicle, unintended acceleration and deceleration is suppressed. It is possible to improve performance and fuel efficiency.

According to the vehicle control method of the first embodiment, in step S22, it is determined whether the amount of change ΔA per unit time of the operation amount A of the accelerator pedal 7A is equal to or less than the threshold value ΔA _th . If the amount of change ΔA is less than or equal to the threshold value ΔA _th , the control unit 9 determines that the vehicle is in a constant velocity control state.

Even if the driver attempts to control the vehicle at a constant speed, the operation amount A changes due to variations in the operation of the accelerator pedal 7A. Therefore, if the amount of change ΔA for a predetermined time is less than or equal to the threshold value ΔA _th , the control unit 9 determines that the change in the operation amount A is caused by variations in driver operation, and determines that the state is a constant velocity control state. . In this way, it is possible to determine whether or not the vehicle is in the constant speed control state using the operation amount A of the accelerator pedal 7A, so that in the constant speed control state, variations in vehicle speed V can be suppressed and the occurrence of discomfort for the driver can be suppressed. I can do it.

According to the vehicle control method of the first embodiment, further, in step S21, which is a factor determination step, the control unit 9 determines whether or not there is a deceleration factor in front of the vehicle that can be a factor for deceleration control. . Then, if there is no deceleration factor (S21: No) and the vehicle is in a constant velocity state (S22: Yes), the control unit 9 performs a correction step (S3, S5).

Even if it can be determined from the operation amount A of the accelerator pedal 7A that the vehicle is in a constant velocity control state, if there is a deceleration factor ahead in the direction of travel of the vehicle, the driver must prepare for future deceleration. There may be no intention to maintain a constant velocity control state. Therefore, if a deceleration factor exists (S21: Yes), the process of step S4 is performed, and the correction steps (S3, S5) are not performed. By doing so, the vehicle speed V is set according to the operation amount A of the accelerator pedal 7A by the driver, so that it is possible to suppress the occurrence of a sense of discomfort for the driver.

According to the vehicle control method of the first embodiment, in step S21, for example, it is detected from the map information stored in advance in the navigation device 4 that a railroad crossing, toll booth, curve, etc. are present in the vehicle travel route. In this case, the surrounding information of the vehicle received via the external communication device 5 indicates that the traffic light ahead is red, and the forward vehicle detection unit 1 detects that there is another vehicle ahead. If so, it is determined that there is a deceleration factor. By making this determination, it is possible to prevent the driver from feeling uncomfortable by not making any corrections in preparation for future driver operations.

According to the vehicle control method of the first embodiment, as shown in FIG. 3(A), the corrected torque command value T ^* is compared with the pre-correction torque command value T ^** , and the ideal torque command value is The difference from T _id is corrected to become smaller. By doing so, the torque command value T ^* changes according to the operation amount A while suppressing the change in the vehicle speed V. If the vehicle speed V does not change at all in accordance with the operation amount A of the accelerator pedal 7A, the driver's operation feeling (driveability) will deteriorate. By changing the torque command value T ^* according to the operation amount A, deterioration of drivability can be suppressed.

(First modification)
In the first embodiment, an example has been described in which the gain G is set so that the pre-correction torque command value T ^** approaches the ideal torque command value T _id . In the first modification, there are cases where the pre-correction torque command value T ^** is larger than the ideal torque command value _Tid , and cases where the pre-correction torque command value T ^** is smaller than the ideal torque command value _Tid . An example in which the degree of approach to the ideal torque command value T _id differs will be explained.

In this modification, processing equivalent to the constant velocity control of the first embodiment shown in FIG. 2 is performed, but the detailed setting method of the gain G in step S3 is different.

In step S3, if the pre-correction torque command value T ^** is larger than the ideal torque command value _Tid , the control unit 9 controls the torque command value T ^* to become smaller and closer to the ideal torque command value _Tid . Set a gain G smaller than 1. Here, the torque command value T ^* is set to, for example, 0.8 so as to be closer to the ideal torque command value _Tid .

On the other hand, if the pre-correction torque command value T ^** is smaller than the ideal torque command value _Tid , the control unit 9 controls the torque command value T ^* to increase and approach the ideal torque command value _Tid . , 1 is set. In this modification, the gain G is set to, for example, 1.1. With this setting, if the pre-correction torque command value T ^** is smaller than the ideal torque command value _Tid , the torque command value T ^* approaches the ideal torque command value _Tid , but before correction When compared with the case where the torque command value T ^** is larger than the ideal torque command value T _id , the value is not closer to the ideal torque command value T _id .

That is, when the pre-correction torque command value T ^** is larger than the ideal torque command value _Tid , the difference between the gain G and "1" when it matches the ideal torque command value _Tid is 0.2. be. On the other hand, when the pre-correction torque command value T ^** is smaller than the ideal torque command value _Tid , the difference from the gain G of "1" is 0.1.

According to such a first modification, the following effects can be obtained.

In the correction steps of steps S3 and S5, if the pre-correction torque command value T ^** is larger than the ideal torque command value _Tid , the gain G becomes 0.8, and the pre-correction torque command value T ^** becomes the ideal torque command. If it is smaller than the value T _id , the gain G is 1.1. In other words, when the pre-correction torque command value T ^** is smaller than the ideal torque command value _Tid , the pre-correction torque command value T ^** is a value closer to 1 than when it is larger than the ideal torque command value _Tid . Become.

Therefore ^, when the pre-correction torque command value T ^** is larger than the ideal torque command value _{Tid ,} the ideal torque command value It is corrected to a value closer to T _id . By doing so, when the pre-correction torque command value T ^** is larger than the ideal torque command value T _id , the torque command value T ^* becomes smaller and the vehicle speed V becomes slower. It is possible to reduce power consumption in the motor.

(Second modification)
In the second modification, another method of setting the gain G will be explained.

In this modification, processing similar to the constant velocity control of the first embodiment shown in FIG. 2 is performed, but the detailed setting method of the gain G in step S3 is different.

In step S3, the control unit 9 calculates the gain G in the same manner as in the first embodiment, and then changes the gain G in accordance with the vehicle speed V. Specifically, when the vehicle speed V is larger than a threshold value, which is the average vehicle speed limit in urban areas, the control unit 9 does not change the gain G to the value calculated in step S3, and when the vehicle speed V is lower than the threshold value. If G is also small, the gain G is changed to approach 1.

According to such a second modification, the following effects can be obtained.

Even if there is no deceleration factor in step S21 and it is determined in step S22 that the vehicle is in a constant speed control state, if the vehicle speed V is smaller than the threshold value which is the average vehicle speed limit in urban areas and is relatively slow, Since you are driving in a city area, there is a high possibility that speed changes will occur. Therefore, the control unit 9 sets the gain G to a value close to 1 so that the torque command value T ^* is not close to the ideal torque command value T _id but close to the pre-correction torque command value T ^** .

On the other hand, if the vehicle speed V is larger than the threshold value, the control unit 9 changes the gain G set in step S3 because the vehicle is traveling on a highway or the like and there is a low possibility that a speed change will occur. do not have. By doing this, the gain G is corrected by further determining the cause of the speed change, so that it is possible to suppress the driver from feeling uncomfortable.

(Third modification)
In the third modification, still another method of setting the gain G will be described.

In this modification, processing equivalent to the constant velocity control of the first embodiment shown in FIG. 2 is performed, but the detailed setting method of the gain G in step S3 is different.

In step S3, the control unit 9 calculates the gain G in the same manner as in the first embodiment, and then causes the navigation device 4 to change the gain G based on the road condition.

Even if there is no deceleration factor in step S21 and it is determined in step S22 that the vehicle is in a constant speed control state, it is determined that there is a high possibility that a speed change will occur if the vehicle is traveling in a city area or the like. Therefore, the control unit 9 further determines the possibility that a speed change will occur based on the road condition, and the higher the possibility, the closer the torque command value T ^* is to the pre-correction torque command value T ^** . , set the gain G to a value close to 1. On the other hand, if the possibility is low, the control unit 9 does not change the gain G set in step S3.

According to such a third modification, the following effects can be obtained.

Compared to the second modification, the control unit 9 determines the possibility of a speed change using the road condition obtained from the navigation device 4 instead of the vehicle speed V, and the higher the possibility, the more the gain G is set to 1. Change to a similar value. By doing so, it is possible to suppress the driver from feeling uncomfortable due to speed changes.

(Second embodiment)
In the first embodiment, an example has been described in which the constant velocity control state in step S2 is determined based on predetermined conditions. In the second embodiment, an example will be described in which the conditions for determining the constant velocity control state in step S2 are learned.

FIG. 4 is a flowchart showing constant velocity control according to the second embodiment. Compared to the constant velocity control of the first embodiment shown in FIG. 2, the process of step S7 is provided after the process of step S6.

In step S7, the control unit 9 changes the criteria for determining the constant velocity control state through a learning process. Specifically, the control unit 9 determines whether or not the determination of the constant velocity control state is appropriate based on whether the brake pedal is operated or not, and changes the determination criteria. In this way, the determination of the constant velocity control state can be optimized. Note that step S7 is an example of a threshold value correction step.

For example, the control unit 9 determines that there is no deceleration factor when the distance to the vehicle ahead is equal to or greater than a predetermined distance L _th (S21: No), and determines that the constant speed control state is in place (S22: Yes), It is assumed that the gain G is set (S3) and the drive system 8 is controlled using the set gain G. Thereafter, while the drive system 8 is being controlled by the corrected torque command value T ^* , if the operation amount A exceeds the threshold value ΔAth or if the brake pedal is operated to decelerate, the control unit 9 determines that the deceleration factor is not appropriate and changes the predetermined distance L _th to a longer value.

In addition, in step S22, the control unit 9 determines that the constant velocity control state is present when the amount of change ΔA of the operation amount A of the accelerator pedal 7A per unit time is less than or equal to the threshold value ΔAth (S22: Yes). . Thereafter, while the drive system 8 is being controlled by the corrected torque command value T ^* , if the operation amount A exceeds the threshold value ΔAth or if the brake pedal is operated to decelerate, the control unit 9 determines that the constant velocity control state is not appropriate and changes the threshold value ΔAth significantly. In this way, the determination of the constant velocity control state can be optimized.

Note that, as described above, the control unit 9 not only changes the condition for determining the constant speed state when the operation amount A exceeds the threshold value ΔAth or when the brake pedal is operated, but also changes the driving history for a predetermined time. The judgment conditions may be changed using .

According to the second embodiment, the following effects can be obtained.

According to the vehicle control method of the second embodiment, the torque command value T ^* is determined by correction in the correction steps in steps S3 to S5, and the drive system 8 is driven using the torque command value T ^* . Thereafter, if an operation that does not result in a constant velocity control state is received, such as when the operation amount A exceeds the threshold value ΔAth or when a deceleration operation is performed using the brake pedal, the control unit 9 performs step S2. It is determined that the determination of the constant velocity control state was not appropriate, and the conditions used for the determination are changed. By doing so, it is possible to improve the accuracy of determining the constant velocity control state, so that driving control can be performed in accordance with the driver's intention.

(Third embodiment)
In the second embodiment, an example has been described in which the conditions for determining the constant velocity control state in step S22 are changed by learning. In the third embodiment, an example will be described in which the method for setting the gain G is changed by learning.

FIG. 5 is a flowchart showing constant velocity control according to the third embodiment. Compared to the constant velocity control of the first embodiment shown in FIG. 2, the process of step S8 is provided after the process of step S6.

In step S8, the control unit 9 determines whether the correction method is appropriate through a learning process. Specifically, the control unit 9 determines whether the set value of the gain G is appropriate based on whether the brake pedal is operated or not, and corrects the method for setting the gain G. Note that step S8 is an example of a gain calculation method correction step.

For example, in step S22, the control unit 9 determines that the constant velocity control state is in the case where the change amount ΔA of the operation amount A of the accelerator pedal 7A per unit time is less than or equal to the threshold value ΔAth (S22: Yes), and then, Assume that while the drive system 8 is being controlled by the corrected torque command value T ^* , the operation amount A exceeds the threshold value ΔAth, or the brake pedal is operated to decelerate. In such a case, the control unit 9 determines that the driver feels a loss of operational feel, and modifies the setting method to set the gain G to a value close to 1. By doing so, the torque command value T ^* becomes a value close to the pre-correction torque command value T ^** , so that constant velocity control can be performed in accordance with the driver's intention.

According to the third embodiment, the following effects can be obtained.

According to the vehicle control method of the third embodiment, the torque command value T ^* is obtained through correction in the correction steps in steps S3 to S5, and the drive system 8 is driven using the torque command value T ^* . Thereafter, if an operation that does not result in a constant velocity control state is received, such as when the operation amount A exceeds the threshold value ΔAth or when a deceleration operation is performed using the brake pedal, the control unit 9 performs step S3. It is determined that the set value of gain G is not appropriate, and the setting method is changed so that gain G is set to a value closer to 1. By doing so, the setting value of the gain G can be set more appropriately, so that driving control can be performed in accordance with the driver's intention.

(Fourth embodiment)
In the first embodiment, an example has been described in which the torque command value T ^* is set using the gain G when the constant velocity control state is determined. In the fourth embodiment, an example will be described in which the torque command value T ^* is set by another method.

FIG. 6 is a flowchart of constant velocity control according to the fourth embodiment. In this embodiment, when compared with the constant velocity control of the first embodiment shown in FIG. 2, the process of step S1A is performed instead of step S1, and the process of step S3A is performed instead of step S3. Also, step S4 is deleted.

In step S1A, the control unit 9 calculates a torque command value T ^* according to the operation amount A of the accelerator pedal 7A. Note that this calculation method is the same calculation method as the pre-correction torque command value T ^** in step S1 in the first embodiment.

In step S3A, the control unit 9 calculates, based on the current vehicle speed V, a torque command value T ^* required to maintain the vehicle speed V. At this time, the torque command value T ^* calculated in step S1A is overwritten by the torque command value T ^* calculated in step S3A.

In step S6, the control unit 9 drives the motor of the drive system 8 using the torque command value T ^* calculated in step S1A or step S3A. Note that if there is an event that changes the vehicle speed V (S21: Yes) or if the driver does not intend to drive at a constant speed (S22: No), the control unit 9 performs the calculation in step S1A. The motor of the drive system 8 is driven using the torque command value T ^* thus obtained.

FIG. 7 is a timing chart of the state of the vehicle when the constant velocity control of this embodiment is performed.

As shown in FIG. 7(C), there is fluctuation in the operation amount A of the accelerator pedal 7A. However, as shown in FIG. 7(B), the torque command value T ^* required to maintain the current vehicle speed V is calculated. Note that the torque command value T ^* is assumed to match the ideal torque command value _Tid . Therefore, as shown in FIG. 7(A), the vehicle speed V can be set to a constant ideal vehicle speed V _id .

According to the fourth embodiment, the following effects can be obtained.

According to the vehicle control method of the fourth embodiment, the torque command value T ^* required to maintain the current vehicle speed V is calculated, and the vehicle speed V becomes constant as shown in FIG. 7(A). . This calculation of the torque command value T ^* has a simpler configuration than the setting method using the gain G in the first embodiment, so the configuration of the control unit 9 can be simplified.

(Fifth embodiment)
In the fourth embodiment, an example has been described in which a torque command value T ^* that keeps the vehicle speed V constant is calculated, and the motor is controlled using the torque command value T ^* . In the fifth embodiment, an example will be described in which after setting the torque command value T ^* such that the vehicle speed V is constant, a correction is made to improve drivability and change it according to the operation amount A of the accelerator pedal 7A. do.

FIG. 8 is a flowchart showing constant velocity control of this embodiment. In comparison with the constant velocity control ^of the fourth embodiment shown in FIG. A process of step S5A is provided to perform additional correction according to. Step S5A is an example of an additional correction step. According to the fifth embodiment, the following effects can be obtained.

In step S5A, which is an additional correction step, the control unit 9 corrects the torque command value T ^* , which is the constant velocity torque command value, according to the operation amount A of the accelerator pedal 7A. Specifically, when the amount of change ΔA of the manipulated variable A is large, the control unit 9 performs additional correction such that the torque command value T ^* is not constant but changes to a value that corresponds to the manipulated variable A. When the amount of change ΔA is small, the control unit 9 does not additionally correct the torque command value T ^* and keeps the torque command value T ^* at a constant value. By doing so, when the driver intentionally changes the operation amount A of the accelerator pedal 7A, the driver can easily feel the change in speed caused by the change in the operation amount A of the accelerator pedal 7A, which improves drivability. You can improve your performance.

(Sixth embodiment)
In the sixth embodiment, an example of suppressing unintended regenerative braking will be described.

The operation amount A of the accelerator pedal 7A has an acceleration region and a deceleration region. The boundary value between the acceleration region and the deceleration region corresponds to the operation amount threshold value A _thc for determining power running operation and regenerative braking in the drive system 8. When the operation amount A of the accelerator pedal 7A is larger than the operation amount threshold value A _thc , it is determined that the vehicle is in the acceleration region, power running is performed, and the vehicle speed V is accelerated. When the operation amount A of the accelerator pedal 7A is smaller than the operation amount threshold value A _thc , it is determined that the vehicle is in the deceleration region, and the vehicle speed V is decelerated by regenerative braking.

FIG. 9 is a flowchart showing constant velocity control of this embodiment. Compared to the constant velocity control of the first embodiment shown in FIG. 2, the process of step S9 is provided after the process of step S3 and after the process of step S6.

Note that in step S1, if the operation amount A of the accelerator pedal 7A is larger than the operation amount threshold A _thc , it is determined that the accelerator is in the acceleration region, a positive pre-correction torque command value T ^** is set, and the accelerator pedal is When the operation amount A of the pedal 7A is smaller than the operation amount threshold A _thc , it is determined that the vehicle is in the deceleration region, and a negative pre-correction torque command value T ^** is set.

In step S9, a lower limit value is set for the operation amount A of the accelerator pedal 7A. In step S1, if the operation amount A of the accelerator pedal 7A enters the deceleration region due to variations in pedal operation, a negative pre-correction torque command value T ^** is set. However, if negative torque is generated when the driver intends to perform constant velocity control, unintended regenerative braking will be performed. Therefore, in order to suppress unintended regenerative braking, a lower limit value that is larger than the operation amount threshold A _thc is set for the operation amount A of the accelerator pedal 7A, so that the operation amount A does not fall below the operation amount threshold A _thc . Do it like this. By doing so, it is possible to suppress the occurrence of unnecessary braking. The process in step S9 is an example of a lower limit value setting step.

Such processing in step S9 is particularly effective when the vehicle is running at low speed, when the vehicle speed V is slow. During low-speed driving, the operation amount A of the accelerator pedal 7A tends to change near the operation amount threshold A _thc , which is the threshold between the acceleration region and the deceleration region, so the operation amount A of the accelerator pedal 7A falls below the operation amount threshold A _thc . There are many things. Therefore, by providing a lower limit value for the operation amount A of the accelerator pedal 7A that is larger than the operation amount threshold value A _thc , it is possible to suppress the occurrence of unnecessary braking. Note that the operation amount A of the accelerator pedal 7A may be prevented from falling below the operation amount threshold A _thc by correcting the operation amount threshold A _thc to a small value to change the acceleration region and the deceleration region.

According to the sixth embodiment, the following effects can be obtained.

In a vehicle control method that performs regenerative braking according to the operation amount A of the accelerator pedal 7A, in the command value calculation step of step S1, if the operation amount A is in the acceleration region, power running is performed, and the accelerator pedal 7A is When the manipulated variable A is in the deceleration region, regenerative braking is performed. However, especially when the vehicle speed V is slow and the vehicle is running at low speed, if the operation amount A enters the deceleration region unintentionally by the driver due to fluctuations in pedal operation, it may be difficult for the driver to perform regenerative braking. Unintended deceleration occurs.

Therefore, in the lower limit setting step of step S9, if the operation amount A of the accelerator pedal 7A enters the deceleration region when it is determined that the constant velocity control state is in effect, the operation amount A of the accelerator pedal 7A is set to the operation amount threshold. Set a lower limit higher than A _THC . By doing so, it is possible to prevent unintended deceleration from occurring due to the manipulated variable A entering the deceleration region in the constant velocity control state.

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. do not have.

1 Front vehicle detection unit 4 Navigation device 5 External communication device 7 Accelerator operation amount detection sensor 8 Drive system 9 Control unit 10 Control system

Claims (14)

A control method for an electric vehicle, wherein a deceleration region and an acceleration region are provided in an operation range of an accelerator pedal, and acceleration/deceleration control is executed according to the operation amount of the accelerator pedal, the method comprising:
a command value calculation step of calculating a torque command value for the motor according to the operation amount;
When the electric vehicle is in a constant speed control state where the electric vehicle is controlled to run at a constant speed, the torque command value is corrected so that a change in the speed of the electric vehicle according to the operation amount is suppressed. a correction step to
A method for controlling an electric vehicle, comprising: a motor control step of controlling the motor based on the torque command value corrected in the correction step. A method for controlling an electric vehicle according to claim 1,
a constant velocity determination step in which the constant velocity control state is determined when the amount of change in the manipulated variable per unit time is less than a threshold value that is the maximum value of the manipulated variable due to fluctuations in the driver's operation; A method for controlling an electric vehicle further comprising: A method for controlling an electric vehicle according to claim 2, comprising:
If it is determined that the amount of change in the manipulated variable per unit time exceeds the threshold value after the constant speed control state is determined based on the driving history, the threshold value is corrected to be larger. A method for controlling an electric vehicle, further comprising a threshold value correction step. A method for controlling an electric vehicle according to claim 2 or 3,
further comprising a factor determination step of determining the presence or absence of a deceleration factor that is a factor for deceleration control using road conditions;
Control of the electric vehicle, wherein the correction step is executed when it is determined that the constant speed control state is in the constant speed control state in the constant speed determining step, and when it is determined that there is no deceleration factor in the factor determining step. Method. The method for controlling an electric vehicle according to claim 4,
The factor determining step includes map information stored in advance, surrounding information received from outside the electric vehicle via a communication unit, and other information in front of the electric vehicle detected by a forward vehicle detection unit. A method for controlling an electric vehicle, wherein the presence or absence of the deceleration factor is determined based on at least one piece of information indicating the presence or absence of a vehicle. A method for controlling an electric vehicle according to any one of claims 2 to 5,
In the correction step,
A gain for the torque command value calculated in the command value calculation step, which reduces the deviation between the torque command value and an ideal torque command value for maintaining the vehicle speed in the constant velocity control state. Calculate,
A method of controlling an electric vehicle, wherein the torque command value is multiplied by the gain. The method for controlling an electric vehicle according to claim 6,
If it is determined that the amount of change in the manipulated variable per unit time exceeds the threshold value after the constant speed control state is determined based on the driving history, the gain closer to 1 is calculated. A method for controlling an electric vehicle, further comprising a gain calculation method modification step of modifying a gain calculation method so that the gain calculation method is The method for controlling an electric vehicle according to claim 6,
In the correction step, the gain is calculated to be a value closer to 1 when the torque command value is smaller than the ideal torque command value than when the torque command value is larger than the ideal torque command value. A method for controlling electric vehicles. The method for controlling an electric vehicle according to claim 6,
In the method for controlling an electric vehicle, in the correction step, the gain is calculated to have a value closer to 1 as the speed of the electric vehicle is slower. The method for controlling an electric vehicle according to claim 6,
Furthermore, it determines the possibility of speed changes based on map information,
In the correction step, the gain is calculated to have a value closer to 1 as the possibility of the determined speed change is higher. A method for controlling an electric vehicle according to any one of claims 2 to 5,
In the correction step,
Calculate a constant velocity torque command value that makes the speed of the electric vehicle constant,
In the motor control step, the motor is controlled based on the constant velocity torque command value. The method for controlling an electric vehicle according to claim 11,
After the correction step, the greater the amount of change per unit time in the manipulated variable, the further correction is made to the constant velocity torque command value so that it approaches the torque command value calculated in the command value calculation step. A method for controlling an electric vehicle, further comprising an additional correction step. A method for controlling an electric vehicle according to any one of claims 2 to 12,
When it is determined that the constant velocity control state is in the constant velocity control state in the constant velocity determination step, and the manipulated variable falls within the acceleration region, the manipulated variable is less than the boundary value between the deceleration region and the acceleration region. A method for controlling an electric vehicle, further comprising a lower limit setting step in which the lower limit value is set so that the lower limit value does not fall below a lower limit value, which is a large value. an operation amount detection sensor that detects the amount of operation of the accelerator pedal;
motor and
A control device for an electric vehicle, comprising: a control unit that provides a deceleration region and an acceleration region in the operation range of the accelerator pedal and executes acceleration/deceleration control according to the operation amount,
The control unit includes:
calculating a torque command value for the motor according to the operation amount;
A control device for an electric vehicle that corrects the torque command value so that a change in speed of the electric vehicle is suppressed when the electric vehicle is in a constant speed control state in which the electric vehicle runs at a constant speed.

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