JP2023059723A - Driving support device - Google Patents

Abstract

To provide a driving support device capable of reducing a sense of discomfort upon switching between control by a user's operation and ACC control.SOLUTION: A driving support device includes: first control means which performs control to accelerate and decelerate an own vehicle mounted with a drive motor for generating power for traveling, with first request torque requested for maintaining an inter-vehicle distance between the own vehicle and a preceding vehicle ahead thereof at a target value, and to allow the own vehicle to travel while following the preceding vehicle; second control means which performs control to accelerate and decelerate the own vehicle with second request torque requested in response to operation performed by a user of the own vehicle; and restriction means which restricts the variation per unit time of torque for driving a wheel when the first request torque is greater than the second request torque upon the start of the control by the first control means.SELECTED DRAWING: Figure 3

Description

The present invention relates to a driving assistance device.

Recent vehicles are equipped with a function that allows the vehicle to follow a preceding vehicle, that is, a so-called adaptive cruise control (ACC) function. During control by the ACC function (ACC control), a target inter-vehicle distance between the vehicle and the preceding vehicle is set based on the vehicle speed of the vehicle. -target inter-vehicle distance) is obtained. Also, the relative speed between the own vehicle and the preceding vehicle is obtained. Then, a target acceleration/deceleration is set according to the inter-vehicle distance deviation and the relative speed, and the driving torque of the vehicle is controlled so that the vehicle accelerates/decelerates at the target acceleration/deceleration.

Further, for example, a series hybrid system includes an engine, a generator motor that generates power using the power of the engine, a drive motor that generates drive power for running, and a battery that stores the power supplied to the drive motor. be In a vehicle equipped with the hybrid system, when the output required of the drive motor is smaller than the output of the battery, the drive motor is driven by electric power from the battery, and driving force is transmitted from the drive motor to the drive wheels. On the other hand, when the output required of the drive motor exceeds the output of the battery, the power of the engine is converted into electric power by the generator motor, and the drive motor is driven by the electric power from the generator motor. is transmitted. When the vehicle decelerates, the drive motor is regeneratively operated, so that power transmitted from the drive wheels to the drive motor is converted into electric power. At this time, the drive motor acts as resistance to the traveling drive system, and the resistance acts as torque (regenerative torque) for braking the vehicle. Electric power generated by the drive motor is stored in a battery and used to drive the drive motor (see Patent Document 1, for example).

The system as described above sets a target value (required torque) when controlling the drive torque. The required torque includes an ACC required torque calculated and set by ACC control and a user required torque set according to the user's pedal operation. Some such systems employ the greater of the ACC requested torque and the user requested torque during ACC control.

JP 2015-098307 A

In the system as described above, for example, when the changeover switch is operated during control by the user's pedal operation and ACC control is started, the required torque adopted as the target value is changed from the user required torque to the ACC required torque. switch to As a result, the user's sensation of acceleration/deceleration suddenly changes, which may cause discomfort or anxiety. This phenomenon tends to appear remarkably in a series hybrid system in which regenerative torque tends to act strongly. More specifically, for example, when ACC control is started while the vehicle is approaching a preceding vehicle during inertial deceleration in normal running, brake control is performed immediately after ACC control is started. At that time, the required torque is switched from the user-requested torque to the ACC-required torque, so the drive torque suddenly increases. In this case, the user feels that the deceleration G is missing even though he/she wants to decelerate.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a driving support device that can reduce discomfort when switching between user-operated control and ACC control.

In order to solve the above-described problems and achieve the object, a driving support system according to the present invention is a vehicle equipped with a drive motor that generates power for running, and the following distance between a vehicle and a preceding vehicle in front of the vehicle is provided. A first control means for controlling the vehicle to run following the preceding vehicle by accelerating and decelerating the own vehicle with the first required torque required to maintain the target value, and an operation performed by the user of the own vehicle second control means for controlling acceleration and deceleration of the own vehicle with a second demand torque requested in response; and when the control by the first control means is started, the first demand torque is greater than the second demand torque. and limiting means for limiting the amount of change per unit time of the torque for driving the wheels.

According to this configuration, when the torque for driving the wheels is changed to increase, the amount of change per unit time is limited, so that a sense of incongruity when switching between the control by the second control means and the control by the first control means is avoided. For example, it is possible to suppress the occurrence of inconvenience such as feeling as if the deceleration G suddenly disappeared or as if the acceleration started suddenly.

Further, in the driving assistance device according to the present invention, when the torque reaches a predetermined threshold value while the amount of change in the torque for driving the wheels is being limited, the limiting means suppresses the limitation of the amount of change, A change is made to raise the torque for driving the wheels to the first required torque.

According to this configuration, it is possible to appropriately round up the redundant change amount limitation, and it is possible to suppress the deterioration of the acceleration/deceleration response due to the change amount limitation.

Further, in the driving support device according to the present invention, the limiting means limits the amount of change in the torque for driving the wheels, and the control for decelerating the own vehicle is activated when the control by the first control means is started. If you do, do it.

According to this configuration, it is possible to make it difficult for the user to feel a sense of incongruity by taking measures against the feeling that the deceleration G is suddenly lost in the conventional control.

Further, in the driving support device according to the present invention, the limiting means controls the amount of change in the torque driving the wheels when the control by the first control means changes from decelerating the own vehicle to accelerating the own vehicle. suppress the restrictions on

According to this configuration, rapid acceleration can be achieved.

ADVANTAGE OF THE INVENTION The driving assistance device concerning this invention is effective in the ability to reduce the discomfort at the time of switching of control by a user operation, and ACC control.

FIG. 1 is a block diagram showing the configuration of a hybrid vehicle according to the first embodiment. 2 is a diagram illustrating an example of a functional configuration of a control unit according to the embodiment; FIG. FIG. 3 is a graph showing an example of transition of torque according to the embodiment. FIG. 4 is a graph showing an example of transition of torque according to the embodiment. 5 is a flowchart illustrating an example of the flow of processing executed by the control unit according to the embodiment; FIG.

An example of the driving assistance device according to the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a hybrid vehicle 1 according to the first embodiment. The hybrid vehicle 1 is an example of a vehicle, and includes a drive motor that acts as a resistance in the drive system. In addition, the hybrid vehicle 1 is equipped with a series hybrid system 2 . The hybrid system 2 includes an engine 11 , a generator motor 12 , a drive motor 13 , a battery 14 and a PCU (Power Control Unit) 15 .

The engine 11 is, for example, a gasoline engine, and includes a throttle body, a fuel injector for injecting fuel into intake air, and the like. The throttle body is a part that takes in fuel and air and sends it to the fuel chamber of the engine 11. It includes an electronic throttle valve for adjusting the intake air amount to the combustion chamber of the engine 11, and a throttle for detecting the opening of the electronic throttle valve. It is equipped with a position sensor and a control valve for adjusting the intake air volume during idling such as when the vehicle is stopped. The engine 11 is also provided with a starter for starting the engine.

The generator motor 12 generates power with the power of the engine 11, and is composed of, for example, a permanent magnet synchronous motor. The rotating shaft of the generator motor 12 is mechanically connected to the crankshaft of the engine 11 via gears (not shown). For example, an engine output gear is supported non-rotatably on the crankshaft of the engine 11, and a motor gear is supported non-rotatably on the rotating shaft of the generator motor 12, and the engine output gear and the motor gear are in mesh.

The drive motor 13 generates power for running, and is composed of, for example, a permanent magnet synchronous motor larger than the generator motor 12 . A rotating shaft of the drive motor 13 is connected to a drive system 16 of the hybrid vehicle 1 . The drive system 16 includes a differential gear, and the power of the drive motor 13 is transmitted to the differential gear, and is distributed from the differential gear to the drive wheels 17 consisting of left and right front wheels or rear wheels. As a result, the left and right drive wheels 17 rotate, and the hybrid vehicle 1 moves forward or backward.

The battery 14 is an assembled battery in which a plurality of secondary batteries are combined, and stores electric power. A secondary battery is, for example, a lithium ion battery. The battery 14 outputs DC power of about 200 to 350 V (volt), for example.

The PCU 15 is a unit for controlling the driving of the generator motor 12 and the drive motor 13 and includes a first inverter 21 , a second inverter 22 and a converter 23 .

When the engine 11 is started, the DC power output from the battery 14 is boosted by the converter 23, the boosted DC power is converted into AC power by the first inverter 21, and the AC power is supplied to the generator motor 12. As a result, the generator motor 12 is powered and the engine 11 is motored (cranked) by the generator motor 12 . The engine 11 is started when the ignition plug of the engine 11 is sparked in a state where the rotation speed of the crankshaft of the engine 11 is increased to the rotation speed required for starting by motoring.

When the hybrid vehicle 1 is running, the drive motor 13 is power-running, and the drive motor 13 generates power.

When the output required of the drive motor 13 is smaller than the output of the battery 14, the hybrid vehicle 1 runs in EV mode. That is, the engine 11 is stopped and the generator motor 12 does not generate power, and the drive motor 13 is driven by the power supplied from the battery 14 to the drive motor 13 .

On the other hand, when the output required of the drive motor 13 exceeds the output of the battery 14, the hybrid vehicle 1 runs in HV mode. That is, the power of the engine 11 is converted into AC power by the generator motor 12 by the engine 11 being put into operation and the generator motor 12 being operated to generate electricity (regenerative operation). Then, the AC power from the generator motor 12 is converted into DC power by the first inverter 21, the DC power output from the first inverter 21 is converted into AC power by the second inverter 22, and the AC power is supplied to the drive motor. 13 drives the drive motor 13 .

Further, when the remaining capacity of the battery 14 falls below a predetermined level, the generator motor 12 is operated to generate power while the engine 11 is operating regardless of whether the drive motor 13 is driven or stopped. At this time, the AC power from the generator motor 12 is converted into DC power by the first inverter 21, the DC power output from the first inverter 21 is stepped down by the converter 23, and the stepped-down DC power is supplied to the battery 14. As a result, the battery 14 is charged.

During deceleration of the hybrid vehicle 1, the drive motor 13 is regeneratively operated, and the power transmitted from the drive wheels 17 to the drive motor 13 is converted into AC power. At this time, the drive motor 13 acts as a resistance of the traveling drive system, and the resistance acts as a braking force (regenerative braking force) for braking the hybrid vehicle 1 . At this time, in the PCU 15 , the AC power supplied from the drive motor 13 to the second inverter 22 is converted into DC power by the second inverter 22 , and the DC power output from the second inverter 22 is stepped down by the converter 23 . Then, the battery 14 is charged by supplying the stepped-down DC power to the battery 14 .

The hybrid vehicle 1 is equipped with a plurality of ECUs (Electronic Control Units). Each ECU has a microcomputer (microcontroller unit), and the microcomputer contains, for example, a CPU, nonvolatile memory such as flash memory, and volatile memory such as DRAM (Dynamic Random Access Memory). A plurality of ECUs are connected so as to be capable of two-way communication using CAN (Controller Area Network) communication protocol. Various sensors necessary for control are connected to each ECU, and detection signals of the connected sensors are input. In addition to detection signals input from various sensors, information necessary for control is input to each ECU from other ECUs.

FIG. 1 shows an ECU 31 that controls the hybrid system 2 among the plurality of ECUs. The ECU 31 is an example of a driving support device. The ECU 31 is connected with an accelerator sensor 32 , a vehicle speed sensor 33 , a forward recognition camera 34 (external world recognition means for recognizing the external world around the vehicle), and an ACC changeover switch 35 .

The accelerator sensor 32 outputs a detection signal corresponding to the amount of operation of an accelerator pedal that is stepped on by a driver. The vehicle speed sensor 33 outputs, as a detection signal, a pulse signal synchronized with the rotation of the rotating body that rotates as the hybrid vehicle 1 travels. The ECU 31 obtains the accelerator opening, which is the ratio of the current operation amount to the maximum operation amount of the accelerator pedal, from the detection signal of the accelerator sensor 32 . Further, the ECU 31 obtains the frequency of the detection signal (pulse signal) from the detection signal of the vehicle speed sensor 33, and converts the frequency to the vehicle speed.

The forward recognition camera 34 is, for example, a stereo camera. A stereo camera is a camera capable of continuously photographing still images at a predetermined frame rate, and is capable of detecting the distance to the position of a target in the photographed images from parallax information. The stereo camera is installed, for example, on the windshield behind the rearview mirror at the front center of the vehicle interior so as to be able to capture a wide-angle image of the front of the hybrid vehicle 1 . In addition to the stereo camera, the hybrid vehicle 1 may be provided with a radar as a unit for recognizing the outside world. The radar is installed in the front part of the hybrid vehicle 1 and is a sensor for detecting the situation in a predetermined search range in front of the hybrid vehicle 1 . The radar irradiates a search range with radar waves (millimeter waves, laser), receives reflected waves from objects existing within the search range, and outputs detection signals corresponding to the reflected waves.

The output of the front recognition camera 34 is output to ECU31. Based on the image captured by the front recognition camera 34, the ECU 31 determines the relative speed between a target such as a preceding vehicle and the hybrid vehicle 1, the target inter-vehicle distance from the preceding vehicle, and the target adjustment when following the preceding vehicle. It implements a functional unit (a vehicle-to-vehicle distance calculation unit 301, a relative vehicle speed calculation unit 302, and a target acceleration calculation unit 305, which will be described later) that calculates data necessary for operating the ACC function, such as speed.

Further, the ECU 31 transmits a control signal to the engine 11 when the inter-vehicle distance between the preceding vehicle and the hybrid vehicle 1 becomes larger than the target inter-vehicle distance and acceleration (or contraction and deceleration) becomes necessary. When the engine 11 receives the control signal, the engine 11 transmits a throttle control signal to the throttle body, controls the throttle opening, and transmits a fuel injection control signal to the fuel injector in order to realize acceleration based on the signal, Controls the injection amount of fuel.

The ECU 31 adjusts the throttle opening/closing degree of the engine so that the drive torque corresponding to the accelerator operation amount (accelerator opening) detected by an accelerator sensor (not shown) is normally output (in a state in which the ACC function is not operated). and control the amount of fuel injected by the fuel injector. On the other hand, when the ACC function is operating, as described above, the throttle opening and the fuel injection amount are controlled based on the control signal so that the acceleration corresponding to the signal is obtained regardless of the accelerator operation amount. do.

The ACC function is a follow-up running function that causes the hybrid vehicle 1 to follow and run a preceding vehicle, which is another vehicle ahead of the hybrid vehicle 1 . For example, the steering wheel is provided with an ACC selector switch 35 that accepts an operation for switching ON/OFF of control by the ACC function. When the ACC changeover switch 35 is operated, the ECU 31 starts or ends control by the ACC function. In ACC control (follow-up control), in which the hybrid vehicle 1 is caused to follow a preceding vehicle in front of the hybrid vehicle 1, the following driving to the preceding vehicle and constant-speed driving at a predetermined vehicle speed are automatically performed depending on the presence or absence of the preceding vehicle. switchable. During follow-up running, the hybrid vehicle 1 is accelerated or decelerated so that the inter-vehicle distance between the hybrid vehicle 1 and the preceding vehicle ahead thereof is maintained at the target inter-vehicle distance.

Specifically, a target inter-vehicle distance between the hybrid vehicle 1 and the preceding vehicle is set based on the vehicle speed of the hybrid vehicle 1, and the ECU 31 controls the inter-vehicle distance deviation (=actual inter-vehicle distance) between the target inter-vehicle distance and the actual inter-vehicle distance. -target inter-vehicle distance) is obtained. Also, the ECU 31 obtains the relative speed between the hybrid vehicle 1 and the preceding vehicle. Then, the target acceleration/deceleration of the hybrid vehicle 1 is set by the ECU 31 according to the inter-vehicle distance deviation and the relative speed. A non-volatile memory incorporated in the microcomputer of the ECU 31 stores the characteristics (relationship) of the target acceleration/deceleration with respect to the inter-vehicle distance deviation and the relative speed in the form of a map as a target acceleration/deceleration map. When the target acceleration/deceleration is set, the output of the engine is controlled (automatic acceleration/deceleration) so that the hybrid vehicle 1 accelerates/decelerates at the target acceleration/deceleration.

FIG. 2 is a diagram showing an example of the functional configuration of the control unit 300 according to this embodiment. ECU31 implement|achieves the control part 300 when CPU runs the various programs memorize|stored in memory. The control unit 300 includes a vehicle-to-vehicle distance calculation unit 301, a relative vehicle speed calculation unit 302, a user request torque calculation unit 303, an ACC control unit 304, a target acceleration calculation unit 305, a request non-attainment determination unit 306, a limit cancellation determination unit 307, and a variation limit. It functions as the unit 308 and the like.

In the hybrid system 2 according to the present embodiment, the CPU executes various programs stored in the memory to realize the above-described various functional units, but the present invention is not limited to this, and can be implemented by hardware. It is also possible to realize each functional unit.

The inter-vehicle distance calculation unit 301 calculates a target inter-vehicle distance from the preceding vehicle based on the output of the forward recognition camera 34 . Relative vehicle speed calculation unit 302 calculates the relative speed between a target such as a preceding vehicle and hybrid vehicle 1 based on the output of forward recognition camera 34 .

The user-required torque calculation unit 303 calculates a required torque for driving the wheels according to the accelerator opening (described above) obtained based on the output of the accelerator sensor 32 . The required torque is the target value of the driving torque. Note that the control unit 300 uses the output of the user-requested torque calculation unit 303 to perform control for accelerating and decelerating the hybrid vehicle 1 with the user-requested torque (second demanded torque) requested according to the user's operation (second control example of means).

The ACC control unit 304 is an example of first control means, and controls the own vehicle with the ACC required torque (first required torque) required to maintain the inter-vehicle distance between the own vehicle and the preceding vehicle at a target value. is accelerated or decelerated to follow the preceding vehicle. When the ACC control is turned on by the ACC switch 35, the ACC control unit 304 performs ACC control using the outputs of the inter-vehicle distance calculation unit 301, the relative vehicle speed calculation unit 302, and the user requested torque calculation unit 303. Execute. Also, when the ACC control is turned off by a predetermined behavior of the user, the ACC control unit 304 terminates the ACC control. Here, the user's predetermined behavior is, for example, an operation of switching off the ACC control by the ACC switch 35 or an operation of depressing the brake pedal.

The target acceleration calculation unit 305 calculates a target acceleration/deceleration when following the preceding vehicle based on the output of the forward recognition camera 34 during ACC control. Using the target acceleration/deceleration output from the target acceleration calculation section 305, the ACC control section 304 calculates the ACC required torque, which is the target value of the drive torque during ACC control.

Here, when the control by the user's accelerator pedal operation is switched to the ACC control, and the ACC required torque is larger than the user required torque, the control unit 300 limits the change amount of the required torque per unit time. The request non-arrival determination unit 306, the restriction cancellation determination unit 307, and the change amount restriction unit 308 are used when limiting the amount of change described above.

In other words, request non-attainment determination unit 306 determines whether or not the required torque that has been smaller than the ACC required torque has not reached the ACC required torque since the ACC control being executed was started. .
The change amount limiting unit 308 is an example of limiting means for limiting the amount of change described above. Control is performed to change the required torque by the same amount.
In addition, restriction release determination section 307 determines whether or not the required torque has reached a predetermined threshold value. This threshold value is set so that when the required torque reaches the threshold value, the restriction on the amount of change in the torque that has been performed up to that point is released (finished).

FIG. 3 is a graph showing an example of transition of torque according to the present embodiment. In this figure, the vertical axis of the graph is the torque value (unit: Nm (Newton meter)) and the horizontal axis is time (unit: s (second)). Also, this figure shows transitions of three types of torque, ie, the user requested torque, the ACC requested torque, and the requested torque. This figure also shows the on/off timings of the ACC control and the brake control by the ACC function.

In this example, ACC control is started in a state in which the vehicle is approaching the preceding vehicle during inertial deceleration in normal driving (that is, during acceleration/deceleration control by the user's pedal operation and the accelerator pedal is released). . In this case, brake control is performed immediately after the start of ACC control (that is, along with the start of ACC control). In this example, the user requested torque is constant at -50 (Nm), and the ACC requested torque is constant at -30 (Nm).

In the example shown in FIG. 3, the ACC changeover switch 35 is operated at the timing of 0.9 (s) on the graph during control by the user's accelerator pedal operation (that is, not during ACC control), and 1 (s) on the graph is operated. ), the ACC control is started. As a result, the ACC brake control is also switched from off to on at the timing of 0.9 (s) to 1 (s) on the graph.

In this case, in the conventional system, the required torque (indicated by the thick line), which is the target value of the driving torque, is instantaneously switched as shown by the two-dot chain arrow C, and accordingly, the required torque is changed. The drive torque that is changed by the change is also rapidly increased (increased). In this case, the user feels that the deceleration G is missing even though he/she wants to decelerate, which is a source of discomfort and anxiety for the user.

In contrast, in the present embodiment, when switching the required torque, the amount of change per unit time is limited. Specifically, a value (e.g., 187.5 (Nm/s) or less) is adopted as the amount of change per unit time that does not cause discomfort to the user. conduct. By controlling in this way, the required torque (and drive torque), which conventionally was instantaneously increased by 30 (Nm), is gradually increased over about 2 (s) in the example of FIG. be. This makes it difficult for the user to feel uncomfortable or uneasy.

FIG. 4 is a graph showing an example of transition of torque according to the present embodiment. In this figure, the vertical axis of the graph is the torque value (unit: Nm) and the horizontal axis is the time (unit: s (seconds)). Also, this figure shows transitions of three types of torque, ie, the user requested torque, the ACC requested torque, and the requested torque. This figure also shows the on/off timings of the ACC control and the brake control by the ACC function.

In this example, ACC control is started in a state in which the vehicle is approaching the preceding vehicle during inertial deceleration in normal driving (that is, during acceleration/deceleration control by the user's pedal operation and the accelerator pedal is released). . In this example, the user requested torque is constant at -50 (Nm), and the ACC requested torque is constant at -30 (Nm).

This example differs from the example in FIG. 3 in that the ACC required torque increases from the timing of 1 (s) due to the relationship between the relative speed and the inter-vehicle distance with the preceding vehicle. Note that there is no change in the user-requested torque during this period, that is, the user does not operate the accelerator pedal.

Also, in this example, the ACC required torque changes from a negative value to a positive value at a timing around 1.5 (s). That is, the hybrid vehicle 1 of this example changes from a deceleration state to an acceleration state by ACC control.

In the example shown in FIG. 4, the ACC changeover switch 35 is operated at a timing of 0.9 (s) on the graph during control by user's accelerator pedal operation (that is, not during ACC control), and 1 (s) on the graph is operated. ), the ACC control is started.

In this example, too, in the case of the conventional system, the required torque (indicated by the thick line), which is the target value of the driving torque, is instantaneously switched from the user required torque to the ACC required torque, similar to the above explanation. Along with this, the drive torque also rises sharply.
However, in this embodiment, as in the example of FIG. 3, the amount of change per unit time is limited when switching the required torque. Specifically, a value (for example, 187.5 (Nm/s) or less) that does not give the user a sense of discomfort is adopted as the amount of change per unit time, and the required torque is switched by repeating the change at this value.

Also, in this example, the ACC required torque gradually increases from the timing of 1 (s). For this reason, in the example of FIG. 3, the required torque reaches the ACC required torque around 2 (s), but in the example of FIG. It takes time.

Further, the ACC required torque changes from a negative value to a positive value at a timing (indicated by symbol D) around 1.5 (s). That is, the hybrid vehicle 1 of this example changes from a deceleration state to an acceleration state by ACC control. The required torque, which changes following the ACC required torque, also changes from deceleration to acceleration at a timing (indicated by symbol E) after 2.5 (s). In this embodiment, at this timing, that is, at the timing when the required torque becomes 0 (Nm), the control section 300 performs control so as to immediately fill the difference between the ACC required torque and the required torque.

In the present embodiment, the threshold 0 (Nm) is used as a trigger to control the required torque to match the ACC required torque as described above. I don't mind.

Also, the example shown in FIG. 4 is an example of starting ACC control during inertia deceleration, but the application of the restriction on the amount of change in the required torque per unit time described with reference to FIG. may be subject. For example, even when the user presses the ACC changeover switch 35 while stepping on the accelerator pedal, the change amount limitation illustrated in FIG. 4 may be applied.

FIG. 5 is a flowchart showing an example of the flow of processing executed by the control unit 300 according to this embodiment. This processing implements the ACC control shown in FIGS.

3 and 4 show dots adjacent to each other at intervals of about 0.1 (s). Described as a loop. However, in implementation, the control unit 300 may loop the process at intervals different from those of the present embodiment, for example, loop at intervals of about 8 (ms (milliseconds)).

The control unit 300 first determines whether ACC control is being performed (step S1). If the ACC control is being performed in step S1 (Yes in step S1), the control unit 300 compares the ACC requested torque and the user requested torque (step S2).

If the ACC requested torque exceeds the user requested torque in step S2 (Yes in step S2), the control unit 300 determines that the requested torque that is smaller than the ACC requested torque after the current ACC control is started becomes the ACC requested torque. is not reached (step S3).

If it is determined in step S3 that the required torque has not reached the ACC required torque (Yes in step S3), the control unit 300 determines whether the previous value of the required torque (previous required torque) is less than a predetermined threshold value A. (step S4). Here, the threshold A is, for example, 0 (Nm).

If the previous required torque is less than the threshold A in step S4 (Yes in step S4), the control unit 300 determines whether the difference between the ACC required torque and the previous required torque is greater than a predetermined value (constant B) ( step S5).

If the difference between the ACC required torque and the previous required torque is greater than the constant B in step S5 (Yes in step S5), the control unit 300 performs control to change the required torque to a value obtained by adding the constant B to the previous required torque. (step S6). The amount of change in the required torque is limited to the constant B by this process. After step S6, control unit 300 returns the process to step S1.

If it is determined in step S3 that the required torque has reached the ACC required torque (No in step S3), the control unit 300 advances the process to step S7, matches the required torque to the ACC required torque, and then proceeds to step S7. Return to S1. As a result, the requested torque is maintained in a state of matching the ACC requested torque during the execution of the current ACC control.

If it is determined in step S4 that the previous required torque is equal to or greater than the threshold value A (No in step S4), the control unit 300 advances the process to step S7, adjusts the required torque to the ACC required torque, and then executes the process. is returned to step S1. As a result, when the required torque becomes equal to or greater than the threshold value A while the required torque applied to the current ACC control is gradually increasing, the restriction on the amount of change in the required torque is lifted, and the difference between the required torque and the ACC required torque is eliminated at once. be.

Note that if ACC control is not being performed in step S1 (No in step S1) and if the ACC required torque is equal to or less than the user required torque in step S2 (No in step S2), the control unit 300 proceeds to step S1. Proceed to S8. In step S8, the control unit 300 adopts the user-requested torque determined by the user's pedal operation as the requested torque, matches the requested torque with the user-requested torque, and returns the process to step S1.

The control illustrated in FIGS. 3 and 4 can be implemented by the processing described above. That is, according to the present embodiment, when there is concern about a sudden change in the required torque, by limiting the amount of change, it is possible to reduce discomfort when switching between the control by the user's operation and the ACC control.

Further, according to the present embodiment, the restriction on the amount of change in the required torque can be canceled (finished) when the predetermined condition is cleared.

In the above embodiment, the amount of change per unit time is a fixed value (constant B), but in practice, the amount of change per unit time may be determined by calculation instead of being a constant. For example, the amount of change per unit time may be calculated by fixing the time required for the change. Specifically, if it is desired to finish changing the required torque in 2 (s), the amount of change per unit time can be calculated by the following formula.
Amount of change per unit time = (ACC required torque - current required torque) / (2 (s) / unit time (s))

Also, it is preferable to increase the amount of change in the required torque per unit time as the vehicle speed increases. Further, it is preferable to increase the amount of change in the required torque per unit time as the difference between the ACC required torque and the current required torque increases.

Although several embodiments of the invention have been described above, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, changes, and combinations can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

For example, the present invention is not limited to series hybrid vehicles, and may be applied to parallel hybrid vehicles, electric vehicles, and fuel cell vehicles.

In addition, in the above embodiment, a hybrid vehicle equipped with an engine, a generator motor that generates power using the power of the engine, and a battery that stores electric power has been described as an example, but the implementation is not limited to this. For example, the present invention may be applied to an engine-less electric vehicle or a fuel cell vehicle that includes a drive motor that acts as a resistance in the drive system.

Further, in the above-described embodiment, when the requested torque reaches a predetermined threshold value while the amount of change in the requested torque is limited, the limitation on the amount of change in the torque that has been performed up to that point is canceled (finished). , but not limited to this. For example, rather than ending the limit on the amount of change in torque, it may be weakened. That is, the amount of change per unit time may be changed to a larger value after reaching the threshold than before reaching the threshold.

1... hybrid vehicle (an example of a vehicle), 2... hybrid system,
DESCRIPTION OF SYMBOLS 11... Engine, 12... Generating motor, 13... Drive motor, 14... Battery,
15...PCU, 16...drive system, 17...driving wheel,
21... First inverter, 22... Second inverter, 23... Converter,
31 ... ECU, 32 ... accelerator sensor, 33 ... vehicle speed sensor,
34... Forward recognition camera, 35... ACC changeover switch,
300... control unit,
301 ... distance calculation unit, 302 ... relative vehicle speed calculation unit, 303 ... user required torque calculation unit 304 ... ACC control unit, 305 ... target acceleration calculation unit,
306 -- Request non-fulfillment determination unit, 307 -- Limit release determination unit, 308 -- Change amount restriction unit.

Claims (4)

Accelerates and decelerates the own vehicle with a first required torque required to maintain the inter-vehicle distance between the own vehicle, which is a vehicle equipped with a drive motor that generates driving power, and a preceding vehicle in front of the own vehicle at a target value. a first control means for performing control to follow and run the preceding vehicle;
second control means for controlling acceleration and deceleration of the own vehicle with a second required torque requested according to an operation performed by the user of the own vehicle;
limiting means for limiting the amount of change per unit time of the torque for driving the wheels when the first required torque is larger than the second required torque at the start of the control by the first control means;
A driving support device. When the torque reaches a predetermined threshold value while the amount of change in the torque for driving the wheels is limited, the limiting means suppresses the limitation of the amount of change, and reduces the torque for driving the wheels to the first required torque. The driving assistance device according to claim 1, wherein the change is made to raise the 3. The method according to claim 1, wherein the limiting means limits the amount of change in the torque that drives the wheels when control for decelerating the own vehicle is activated with the start of control by the first control means. The driving assistance device described. The limiting means, when the control by the first control means shifts from decelerating control to accelerating control of the own vehicle, limits the amount of change in the torque that drives the wheels. The driving assistance device according to any one of the items.

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