JP5488223B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device that starts control by suppressing at least one of driving force applied to a tire and increasing braking force when a sudden decrease in running resistance is detected.

  Conventionally, it is determined that the vehicle has finished climbing the level difference from the fact that the vehicle acceleration is greater than a predetermined value or that the moving average of the wheel angular acceleration is greater than a predetermined value, and the driving force applied to the tire is suppressed. 2. Description of the Related Art A driving force control apparatus for starting over a step that starts control by at least one of an increase in braking force is known (see, for example, Patent Document 1).

JP 2007-45230 A

  However, in the conventional driving force control device for overcoming a step, the detection timing of the sudden decrease in running resistance is delayed, and from the time when the sudden decrease in running resistance is detected until the point at which the step ends and the vehicle acceleration becomes maximum. The time interval becomes shorter. For this reason, the vehicle acceleration (change rate of vehicle acceleration) changes suddenly so that the vehicle accelerates until the driving force suppression control is started, and suddenly decelerates when the driving force suppression control is started. There was a problem of giving.

  In other words, the vehicle acceleration depends on the vehicle driving force and the vehicle speed, and the higher the vehicle driving force and the vehicle speed, the larger the vehicle acceleration, and the required time from the point of detection of a sudden decrease in running resistance to the step end point (maximum vehicle acceleration point). Time is shortened.

  The present invention has been made paying attention to the above-mentioned problem, and it is possible to prevent the delay of the control start timing of the control for suppressing the driving force by detecting the rapid decrease in the running resistance with high accuracy at an early timing. An object is to provide an apparatus.

In order to achieve the above object, the vehicle control apparatus of the present invention is a means provided with a running resistance equivalent value detecting means, a running resistance rapid drop detecting means, and a vehicle driving force control means.
The running resistance equivalent value detecting means detects a running resistance equivalent value due to a disturbance while the vehicle is running.
The traveling resistance rapid decrease detecting means detects a rapid decrease in traveling resistance during traveling of the vehicle based on an integral element of the time change rate of the traveling resistance equivalent value and the vehicle acceleration.
The vehicle driving force control means starts control by at least one of suppression of driving force applied to the tire and increase of braking force when the sudden decrease in running resistance is detected by the running resistance sudden drop detection means.

While the vehicle is running, the running resistance sudden drop detection means detects the sudden drop in running resistance based on the “time change rate of the running resistance equivalent value” and the “integral element of vehicle acceleration” due to disturbance. When a sudden decrease in running resistance is detected, the vehicle driving force control means starts control by suppressing at least one of driving force applied to the tire and increasing braking force.
As described above, when detecting the sudden decrease in the running resistance, the “time change rate of the running resistance equivalent value” and the “integral element of the vehicle acceleration” are used. The “time change rate of the running resistance equivalent value” is information for monitoring a running resistance change such as a sudden drop in running resistance as it is. However, for example, even if the height of the step (disturbance) is the same, the higher the vehicle driving force and the vehicle speed, the greater the negative gradient (time change rate of the running resistance equivalent value) after overcoming the step. Depends on driving force and vehicle speed. Therefore, by combining the “time change rate of the running resistance equivalent value” with the “vehicle acceleration integral element” which is information for monitoring the vehicle driving force and the vehicle speed, the influence on the vehicle driving force and the vehicle speed is eliminated, Increase detection accuracy and enable early detection timing.
In this way, a control that suppresses the driving force by using a combination of “time change rate of running resistance equivalent value” and “integrating element of vehicle acceleration” and detecting a rapid drop in running resistance with high accuracy at an early timing. It is possible to prevent a delay in control start timing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall system diagram illustrating an electric vehicle (an example of a vehicle) on which a control device according to a first embodiment is mounted. It is a control block diagram which shows the whole control logic of the control apparatus of Example 1. FIG. FIG. 3 is a block diagram illustrating a detailed configuration of a control start / end determination unit in the control logic of the control device according to the first embodiment. It is a flowchart which shows the flow of the control start process performed with the electronic control unit 5 of the control apparatus of Example 1. FIG. It is a flowchart which shows the flow of the driving force suppression control process performed by the electronic control unit 5 of the control apparatus of Example 1, and a control end process. It is a flowchart which shows the flow of the driving | running | working resistance rapid fall determination processing performed with the electronic control unit 5 of the control apparatus of Example 1. FIG. It is a time chart which shows the difference in the running resistance sudden fall characteristic by the magnitude | size of the vehicle drive force in a comparative example, and a running resistance sudden fall detection timing. FIG. 6 is a characteristic diagram showing a time change rate of disturbance indicating that jerk varies depending on the vehicle speed even at the same step. FIG. 6 is a characteristic diagram showing a change in disturbance with respect to a moving distance indicating that a disturbance change rate is constant depending on a step height and does not depend on a vehicle speed. FIG. 6 is a characteristic diagram showing a change in travel resistance with respect to a travel distance indicating that a sudden decrease in travel resistance can be detected at the moment when the vehicle starts moving on a step. 5 is a time chart showing characteristics of vehicle driving force, traveling resistance, vehicle acceleration, and moving distance representing an action of detecting a rapid decrease in traveling resistance of Example 1 due to a difference in vehicle driving force when riding on a step. It is a block diagram which shows the detailed structure of the control start / end judgment part in the control logic of the control apparatus of Example 2. It is a flowchart which shows the flow of the driving | running | working resistance rapid fall judgment processing performed with the electronic control unit 5 of the control apparatus of Example 2. FIG. It is a figure which shows the map which determines the regulation value (Set_dFD) of change rate ((DELTA) FD / (DELTA) T) of driving resistance estimated value (FD) with vehicle speed. 7 is a time chart showing characteristics of a vehicle driving force, a driving resistance, a vehicle acceleration, and a driving resistance differential value representing an action of detecting a sudden decrease in driving resistance according to a second embodiment due to a difference in vehicle driving force when riding on a step.

  Hereinafter, the best mode for realizing a vehicle control device of the present invention will be described based on Example 1 and Example 2 shown in the drawings.

First, the configuration will be described.
FIG. 1 is an overall system diagram illustrating an electric vehicle (an example of a vehicle) on which the control device according to the first embodiment is mounted. The overall system configuration will be described below with reference to FIG.

  As shown in FIG. 1, the electric vehicle 1 according to the first embodiment includes a drive motor 2, a braking device 3, a left front wheel tire 4FL (tire), a right front wheel tire 4FR (tire), and a left / right driving system. A rear wheel tire 4RL (tire) and a right rear wheel tire 4RR (tire) are provided.

  The electric vehicle 1 is a front-wheel drive vehicle, and transmits a driving force from a driving motor 2 that is a driving source for generating a driving force of the vehicle to the traveling road surface via the left and right front wheels 4FL and 4FR. Further, the braking force from the braking device 3 that generates the braking force of the vehicle is transmitted to the traveling road surface via the left and right front wheels 4FL and 4FR and the left and right rear wheels 4RL and 4RR.

  As shown in FIG. 1, the electric vehicle 1 according to the first embodiment includes an electronic control unit 5 (vehicle driving force control means), a TCS / ABS controller 6, an accelerator opening sensor 7, and a brake operation as an electronic control system. A quantity sensor 8, a sensor unit 9, and a vehicle speed sensor 10 are provided.

  The electronic control unit (abbreviation: ECU) 5 gives a braking / driving force command to the drive motor 2 and the braking device 3. The electronic control unit 5 inputs information from the TCS / ABS controller 6, the accelerator opening sensor 7, the brake operation amount sensor 8, and the sensor unit 9.

  When the TCS / ABS controller 6 is in an acceleration slip state (including an acceleration slip prediction state) due to excessive driving force to the drive wheels (left and right front wheels 4FL, 4FR) during traveling, Driving force control (TCS control) for reducing the driving force from the driving motor 2 is performed. In addition, when at least one of the four wheels (the left and right front wheels 4FL and 4FR and the left and right rear wheels 4RL and 4RR) is in a braking lock state (including a predicted brake lock state) due to excessive braking force during braking, the brake is locked. The braking force control (ABS control) for controlling (decreasing / holding / increasing) the braking force from the braking device 3 is performed so as to suppress the braking force.

  The accelerator opening sensor 7 detects the accelerator opening based on the driver's accelerator operation. The brake operation amount sensor 8 detects a brake operation amount based on a driver's brake operation.

  The sensor unit 9 inputs vehicle speed information (= vehicle speed information) detected by the vehicle speed sensor 10, calculates necessary information such as vehicle acceleration, vehicle speed, and travel distance as a vehicle state quantity, and an electronic control unit Output to 5.

  FIG. 2 is a control block diagram illustrating the entire control logic of the control device according to the first embodiment. The overall control logic configuration will be described below with reference to FIG.

  As shown in FIG. 2, the electronic control unit 5 includes, as control blocks, a driver requested driving force requested braking force calculating unit 11, a running resistance calculating unit 12, a target driving force generating unit 13, and a control start / end. A determination unit 14 and a target driving force switching unit 15 are provided.

  The driver request driving force request braking force calculation unit 11 calculates the driver request control / drive force FA from the accelerator opening and the brake operation amount by the driver operation, and outputs them.

The running resistance calculation unit 12 calculates a running resistance estimation value FD from a braking / driving target value given to the electric vehicle 1 and a vehicle state quantity captured by the sensor unit 9.
This running resistance estimated value FD is
Estimated running resistance FD = actual driving force-(vehicle weight x vehicle acceleration)
In this equation, the actual driving force is estimated from the driving current to the driving motor 2. Alternatively, it is obtained by substituting the braking / driving target value into the actual driving force value based on the estimation that the actual driving force matches the braking / driving target value.

  The target driving force generation unit 13 is a braking / driving force target value FC generated by the main control from the outputs of the sensor unit 9, the driver required driving force request braking force calculation unit 11, and the running resistance calculation unit 12 to the electric vehicle 1. Is calculated. The target driving force generation unit 13 includes a target driving force calculation unit 13a and an asymptotic characteristic calculation unit 13b.

  The control start / end determination unit 14 determines the driving force control start in the first embodiment from the outputs of the sensor unit 9, the driver required driving force required braking force calculation unit 11, the running resistance calculation unit 12, and the target driving force generation unit 13. Judgment of end of driving force control and switching on / off of Flag. The control start / end determination unit 14 includes a travel resistance rapid decrease determination unit 14a, a control start determination unit 14b, and a control end determination unit 14c.

  The target driving force switching unit 15 determines the braking / driving force target value FC to be given to the electric vehicle 1 based on the flag from the control start / end determination unit 14 and the driver required driving force request braking force calculation unit 11 and target driving force generation. The output is switched to one of the outputs of the unit 13.

  FIG. 3 is a block diagram illustrating a detailed configuration of a control start / end determination unit in the control logic of the control device according to the first embodiment. The configuration of the control start / end determination unit 14 will be described below with reference to FIG.

  As shown in FIG. 3, the control start / end determination unit 14 includes a travel resistance rapid decrease determination unit 14a, a control start determination unit 14b, and a control end determination unit 14c.

The travel resistance rapid decrease determination unit 14a includes a change rate calculation unit 14d that calculates a travel resistance change rate α from the output of the travel distance L and the travel resistance estimated value FD, and a travel resistance sudden rate that is set with the travel resistance change rate α. And a change rate comparison unit 14e that compares with a predetermined value Set_ΔFD that is a decrease determination threshold. Here, the running resistance change rate α is calculated by the equation of ΔFD / ΔL when the moving distance change amount ΔL is between the running resistance estimated value change amount ΔFD. That is, the running resistance change rate α represents a change gradient of the running resistance estimated value FD with respect to the movement distance L.
Hereinafter, the specific content of this control is demonstrated using a flowchart.

  FIG. 4 is a flowchart illustrating the flow of the control start process executed by the electronic control unit 5 of the control device according to the first embodiment. Hereinafter, each step of FIG. 4 will be described.

In step S101, the travel resistance rapid decrease determination unit 14a of the control start / end determination unit 14 determines whether the travel resistance is rapidly decreased. If YES (travel resistance sudden decrease ant), the process proceeds to step S102. In case of NO (no drop in running resistance), go to the end.
Here, “determination of a sudden decrease in running resistance” indicated by an arrow A in FIG. 4 is made according to a flowchart of FIG. 6 described later.

  In step S102, following the determination that the running resistance suddenly decreases in step S101, it is determined whether or not the Flag state is Flag = OFF. If YES (Flag = OFF), the process proceeds to step S103. If NO (Flag = ON), go to end.

  In step S103, following the determination that Flag = OFF in step S102, the driver requested braking / driving force FA, which is the output of the driver requested driving force requested braking force calculation unit 11, and the magnitude of the running resistance estimated value FD are output. It is determined whether or not this control is to be started. If YES (control start), the process proceeds to step S104. If NO (control start is not started), the process proceeds to end.

  In step S104, following the control start determination in step S103, Flag is updated from Flag = OFF to Flag = ON, and the process ends.

  FIG. 5 is a flowchart illustrating the flow of the driving force suppression control process and the control end process executed by the electronic control unit 5 of the control device according to the first embodiment. Hereinafter, each step of FIG. 5 will be described.

In step S201, it is determined whether or not TCS control or ABS control is not operating based on information obtained from the TCS / ABS controller 6. If YES (TCS / ABS control is not operating), step S202 is performed. If NO (TCS / ABS control is operating), the process proceeds to step S206.
As a result, when a highly urgent command value such as TCS control or ABS control occurs, it can be given priority.

  In step S202, following the determination in step S201 that the TCS / ABS control is not operating, it is determined whether or not Flag, which is the output of the control start / end determination unit 14, is Flag = ON, and YES (Flag = If ON, the process proceeds to step S203, and if NO (Flag = OFF), the process proceeds to the end.

In step S203, following the determination that Flag = ON in step S202, the driving force suppression control is executed based on the braking / driving force target value FC generated by the target driving force generator 13, and the process proceeds to step S204. .
Here, the vehicle driving force suppression control employed in the first embodiment aims to realize vehicle behavior in accordance with the driver's request while suppressing the rapid acceleration of the vehicle even when the step is over. For this reason, control is performed to suppress the driving force when a sudden decrease in the driving resistance is detected using the braking / driving force target value FC obtained from the sum of the running resistance estimated value FD and the monotonically increasing variable as the target vehicle driving force.

  In step S204, following the driving force suppression control based on the braking / driving force target value FC in step S203, the driver requested braking / driving force FA, which is the output of the driver requested driving force requested braking force calculation unit 11, and the target driving force. The braking / driving force target value FC generated by the generation unit 13 is acquired, and the process proceeds to step S205.

  In step S205, following the acquisition of the driver required braking / driving force FA and the braking / driving force target value FC in step S204, it is determined whether or not the driver required braking / driving force FA is less than or equal to the braking / driving force target value FC. If YES (FA ≦ FC), the process proceeds to step S206. If NO (FA> FC), the process proceeds to the end.

  In step S206, following the determination that FA ≦ FC in step S205 or the determination that TCS / ABS control is operating in step S201, the flag is updated to Flag = OFF, and the process proceeds to the end. End the flow. If FA> FC, this control is continued with Flag = ON. With this configuration, the driving force does not change suddenly when the vehicle driving force is switched from the output of the target driving force generator 13 to the output of the driver required driving force required braking force calculator 11.

  FIG. 6 is a flowchart illustrating a flow of a travel resistance rapid decrease determination process (part A in FIG. 4) executed by the electronic control unit 5 of the control device according to the first embodiment. Hereinafter, each step of FIG. 6 will be described.

  In step S501, the running resistance estimated value change amount ΔFD is calculated from the running resistance estimated value FD from the running resistance calculating unit 12, and the process proceeds to step S502.

  In step S502, following the calculation of the travel resistance estimated value change amount ΔFD in step S501, the travel distance change amount ΔL corresponding to the travel resistance estimated value change amount ΔFD is calculated from the travel distance L from the sensor unit 9, and step S503 is performed. Proceed to

  In step S503, following the calculation of the travel distance change amount ΔL in step S502, a travel resistance change rate α (= ΔFD / ΔL) is calculated, and the process proceeds to step S504.

  In step S504, following the calculation of the running resistance change rate α (= ΔFD / ΔL) in step S503, the running resistance change rate α (= ΔFD / ΔL) exceeds a predetermined value Set_ΔFD which is a running resistance sudden decrease determination threshold value. If YES (ΔFD / ΔL> Set_ΔFD), the process proceeds to step S505. If NO (ΔFD / ΔL ≦ Set_ΔFD), the process proceeds to step S506.

  In step S505, following the determination that ΔFD / ΔL> Set_ΔFD in step S504, “YES” is output based on the determination that the running resistance suddenly decreases.

  In step S506, following the determination that ΔFD / ΔL ≦ Set_ΔFD in step S504, “NO” is output based on the determination that the running resistance suddenly decreases.

Next, the operation will be described.
First, the “problem of detecting a rapid decrease in running resistance in the comparative example” will be described. The operation of the control device for the electric vehicle 1 according to the first embodiment will be described by dividing it into “the concept of detecting a sudden decrease in running resistance” and “the action of detecting a sudden decrease in running resistance”.

[Problem of detecting sudden decrease in running resistance in comparative example]
FIG. 7 is a time chart showing a difference in travel resistance rapid decrease characteristic depending on the magnitude of the vehicle driving force and a travel resistance rapid decrease detection timing in the comparative example. Hereinafter, based on FIG. 7, the problem of detection of a sudden decrease in running resistance in the comparative example will be described.

  First, a comparative example will be described in which the detection of a sudden decrease in running resistance when overcoming a step is taken when the vehicle acceleration exceeds a threshold value. In the case of this comparative example, when the vehicle driving force at the time of overcoming the step is the solid line characteristic B in FIG. 7, the running resistance reduction characteristic is the solid line characteristic C in FIG. However, when the vehicle driving force is the dotted line characteristic B ′ in FIG. 7 which is lower than the solid line characteristic B in FIG. 7, the running resistance reduction characteristic is the dotted line characteristic C ′ in FIG. 7. Further, when the vehicle driving force is the dotted line characteristic B ″ in FIG. 7 which is higher than the solid line characteristic B in FIG. 7, the running resistance lowering characteristic is the dotted line characteristic C ″ in FIG.

  Since the vehicle acceleration has a relationship of increasing as the running resistance decreases, when the vehicle driving force at the time of stepping over the step is the solid line characteristic B of FIG. 7, the vehicle acceleration increase characteristic is the solid line characteristic D of FIG. It becomes. However, when the vehicle driving force is the dotted line characteristic B ′ in FIG. 7 lower than the solid line characteristic B in FIG. 7, the vehicle acceleration increasing characteristic is the dotted line characteristic D ′ in FIG. 7. Further, when the vehicle driving force is the dotted line characteristic B ″ in FIG. 7 higher than the solid line characteristic B in FIG. 7, the vehicle acceleration increasing characteristic is the dotted line characteristic D ″ in FIG. 7.

  The relationship of this vehicle driving force is the same for the vehicle speed. As shown in the vehicle acceleration characteristic of FIG. 7, on the side where the vehicle speed is fast, the increase characteristic of the vehicle acceleration is the dotted line characteristic D ″ side of FIG. On the slow side, the vehicle acceleration increasing characteristic is on the dotted line characteristic D ′ side in FIG.

  Thus, when the vehicle driving force and the vehicle speed are high, the rising gradient of the vehicle acceleration increases. For this reason, as in the comparative example, if the vehicle acceleration exceeds the threshold when detecting the sudden decrease in running resistance when overcoming a step, the vehicle driving force when overcoming the step is normal at time tn1. A sudden decrease in running resistance is detected, and the end of the step is reached at time tn2. Further, when the vehicle driving force at the time of overcoming the step is high, a sudden decrease in running resistance is detected at time th1, and the end of the step is reached at time th2. The required time from the detection of sudden decrease in running resistance to the end of the step when the vehicle driving force is normal is ΔTn, whereas the required time ΔTh from detection of sudden decrease in running resistance to the end of the step when the vehicle driving force is high is The required time ΔTn in a normal case is shorter.

As described above, when the vehicle driving force and the vehicle speed are high, the required time ΔTh from the detection of the sudden decrease in running resistance to the end of the step is shortened, and thus the vehicle is allowed to accelerate rapidly when the driving force suppression control is performed. A sudden change in vehicle jerk gives the driver a feeling of strangeness.
That is, in order to suppress sudden acceleration after overcoming a step, a rapid decrease in running resistance is detected with high accuracy at an early timing. As a result, it is important to secure a long required time from detection of a sudden decrease in running resistance to the end of the step, and to control driving force suppression or braking force increase during this required time.

[Concept of detection of sudden drop in running resistance]
Hereinafter, based on FIG. 8 to FIG. 10, the concept of detection of travel resistance rapid drop will be described.
First, even with the same level difference, the time change rate of disturbance (running resistance) varies depending on the vehicle speed as shown in FIG. In other words, if only the “time rate of change in running resistance” is sensed in order to suppress sudden acceleration after overcoming a step, the determination is erroneous based on the vehicle speed. That is, as the vehicle speed increases, it is necessary to determine that the driving resistance is rapidly decreasing even if the “time rate of change in driving resistance” is low.

  Therefore, when detecting a sudden decrease in running resistance, the “time change rate of running resistance” and “integral factor of vehicle acceleration (= vehicle speed)” are used. The “time change rate of running resistance” is information for monitoring a running resistance change such as a sudden drop in running resistance. However, for example, even if the height of the step (disturbance) is the same, the higher the vehicle driving force and the vehicle speed, the larger the negative gradient (time change rate of running resistance) after overcoming the step, so that the vehicle driving force It depends on the vehicle speed. Therefore, the dependence on vehicle driving force and vehicle speed is eliminated by combining “time change rate of running resistance” with “vehicle acceleration integral element (= vehicle speed)” which is information for monitoring vehicle driving force and vehicle speed. In addition, the detection accuracy is improved and the detection timing can be accelerated.

An example of this combination is
(Time change rate of running resistance) / (Vehicle speed)
= (Running resistance estimated value FD / unit time) / (travel distance / unit time)
= (Running resistance estimated value FD) / (Movement distance)
Thus, this is an example in which a sudden decrease in running resistance is detected based on the magnitude of (running resistance estimated value FD) / (movement distance) and a threshold value given by a constant value (Example 1).

  In the detection method of the first embodiment, when the time change rate of the disturbance with respect to the moving distance is seen, the change rate of the disturbance is constant depending on the height of the step and does not depend on the vehicle speed, as shown in FIG. It can be seen that the dependence on vehicle speed can be eliminated. Then, when looking at the time change rate of the running resistance with respect to the moving distance, as shown in FIG. 10, it is possible to detect a sudden drop in the running resistance at the moment when the vehicle starts moving on the step (E portion in FIG. 10). Is shown.

And other combination examples are
(Rate change rate of running resistance) = (Estimated running resistance FD) / (Unit time)
(Embodiment 2) This is an example of detecting a sudden decrease in running resistance based on the magnitude of (running resistance estimated value FD) / (unit time) and a threshold given by a lower value as (vehicle speed) is higher (Example 2). .

  In this way, the control of the control that suppresses the driving force by detecting the rapid decrease of the running resistance with high accuracy at an early timing using a combination of the “time change rate of the running resistance” and the “integral factor of the vehicle acceleration”. Delay in start timing can be prevented.

[Detection of sudden decrease in running resistance]
FIG. 11 is a time chart showing the characteristics of vehicle driving force, traveling resistance, vehicle acceleration, and moving distance representing the action of detecting a rapid decrease in running resistance according to the first embodiment due to the difference in vehicle driving force when stepping on a step. Hereinafter, the traveling resistance rapid decrease detection operation will be described with reference to FIGS. 4 to 6 and FIG. 11.

  Time t0 in FIG. 11 is a point in time when driving force application is started by stepping on the accelerator with respect to a step disturbance with high running resistance. Then, the vehicle driving force is increased by the accelerator depressing operation at time t0, and when the running resistance due to the step disturbance is exceeded at time t1, the electric vehicle 1 starts to move over the step.

  Then, overstepping of the step is started, and while the running resistance change rate α (= ΔFD / ΔL) is equal to or less than a predetermined value Set_ΔFD that is a running resistance sudden decrease determination threshold, in the flowchart of FIG. 6, step S501 → step S502 → The process proceeds from step S503 to step S504 to step S506 (running resistance rapid decrease determination NO). Then, when the running resistance change rate α (= ΔFD / ΔL) exceeds a predetermined value Set_ΔFD that is a threshold value for judging a sudden decrease in running resistance, in step S501 → step S502 → step S503 → step S504 in the flowchart of FIG. → Proceed to step S505 (YES in travel resistance rapid decrease determination).

  Then, in the flowchart of FIG. 4, the process proceeds from step S101 to step S102 to step S103 to step S104. That is, based on the establishment of the travel resistance rapid decrease condition (step S101) and the establishment of the control start condition (step S103), in step S104, the flag is rewritten from OFF to ON, and the driving force suppression control is started.

  Then, from the start time t2 of the driving force suppression control, the execution of the driving force suppression control is maintained while the TCS / ABS stop condition and the Flag = ON condition are satisfied. That is, in the flowchart of FIG. 5, the process of step S201 → step S202 → step S203 → step S204 → step S205 → end is repeated. Then, after overcoming the step, when the time when the braking / driving force target value FC coincides with the driver requested braking / driving force FA is reached, in the flowchart of FIG. 5, step S201 → step S202 → step S203 → step S204 → step S205 → Proceeding to step S206, flag is rewritten from ON to OFF in step S206, and the driving force suppression control is terminated.

  In the detection of this sudden decrease in running resistance, the step ends at time t3 in FIG. 11 when the vehicle driving force is the first driving force FA1. That is, the required time ΔT from the traveling resistance rapid decrease detection time t2 to the step end time t3: FA1 is the required time ΔT from the traveling resistance rapid decrease detection time t2 ′ to the step end time t3 in the comparative example using the vehicle acceleration. ': Longer than FA1.

  Further, in the detection of the sudden decrease in running resistance, the step ends at time t4 in FIG. 11 in the case of the second driving force FA2 where the vehicle driving force is low. That is, the required time ΔT from the running resistance rapid decrease detection time t2 to the step end time t4: FA2 is the required time ΔT from the traveling resistance rapid decrease detection time t3 ′ to the step end time t4 in the comparative example using vehicle acceleration. ': Longer than FA2.

In the first embodiment, a configuration is adopted in which a sudden decrease in running resistance is detected when the running resistance change rate α (= ΔFD / ΔL) exceeds a predetermined value Set_ΔFD that is a running resistance sudden drop determination threshold value.
For this reason, regardless of the level of vehicle driving force (or vehicle speed), a rapid decrease in running resistance is detected with high accuracy at an early timing (time t2), and the required time ΔT: FA1 , ΔT: FA2 is secured for a long time. Then, during the required time ΔT: FA1, ΔT: FA2, by controlling the driving force (or increasing the braking force), it is possible to effectively suppress the rapid acceleration after overcoming the step.

Next, the effect will be described.
In the control device for the electric vehicle 1 according to the first embodiment, the following effects can be obtained.

(1) A running resistance equivalent value detecting means (running resistance calculation unit 12) for detecting a running resistance equivalent value (running resistance estimated value FD) due to a disturbance while the vehicle is running;
Based on a time change rate of the running resistance equivalent value (running resistance estimated value FD) and an integral element (vehicle speed or driving force) of vehicle acceleration, a running resistance sudden drop detection is performed to detect a sudden drop in running resistance while the vehicle is running. Means (running resistance rapid decrease determination unit 14a),
Vehicle driving force control means for starting control by at least one of suppression of driving force applied to tire and increase of braking force when the sudden decrease in traveling resistance is detected by the traveling resistance rapid decrease detection means (travel resistance rapid decrease determination unit 14a). (Electronic control unit 5);
Equipped with.
For this reason, the delay of the control start timing of the control which suppresses a driving force can be prevented by detecting the rapid fall of driving resistance with high precision by an early timing.

(2) The travel resistance rapid decrease detection means (travel resistance rapid decrease determination unit 14a) has a change rate (ΔFD / ΔL) of a travel resistance equivalent value (travel resistance estimation value FD) with respect to the travel distance L exceeding a predetermined value set_ΔFD. At this time, it is detected that the running resistance is rapidly decreasing (step S504 → step S505 in FIG. 6).
For this reason, in addition to the effect of (1), by using detection based on the moving distance L determined by the vehicle driving force and the vehicle speed, a rapid decrease in the running resistance can be detected at an early timing regardless of the level of the vehicle driving force and the vehicle speed. Can be detected with high accuracy.

  The second embodiment is an example in which a rapid decrease in running resistance is detected based on a time change rate of running resistance and a threshold given by a lower value as the vehicle speed is higher.

First, the configuration will be described.
FIG. 12 is a block diagram illustrating a detailed configuration of a control start / end determination unit in the control logic of the control device according to the second embodiment. Hereinafter, the configuration of the control start / end determination unit 14 will be described with reference to FIG.

  As shown in FIG. 12, the control start / end determination unit 14 includes a travel resistance rapid decrease determination unit 14a, a control start determination unit 14b, and a control end determination unit 14c.

  The travel resistance rapid decrease determination unit 14a includes a change rate calculation unit 14f that calculates a travel resistance time change rate α ′ from the output of the time and the travel resistance estimation value FD, and a specified value Set_dFD that is a travel resistance rapid decrease determination threshold value from the vehicle speed. And a change rate comparison unit 14g that compares the travel resistance time change rate α ′ with the calculated value. Here, the running resistance time change rate α ′ is calculated by an equation of ΔFD / Δt, which is a ratio of the running resistance estimated value change amount ΔFD and the time Δt required for the change. That is, the running resistance time change rate α ′ represents a time change gradient of the running resistance estimated value FD.

  FIG. 13 is a flowchart illustrating the flow of the travel resistance rapid decrease determination process (part A in FIG. 4) executed by the electronic control unit 5 of the control device according to the second embodiment. Hereinafter, each step of FIG. 13 will be described.

  In step S601, the running resistance estimated value change amount ΔFD is calculated from the running resistance estimated value FD from the running resistance calculation unit 12, and the process proceeds to step S602.

  In step S602, following the calculation of the running resistance estimated value change amount ΔFD in step S601, a time Δt corresponding to the running resistance estimated value change amount ΔFD is calculated by time measurement from the sensor unit 9, and the process proceeds to step S603.

  In step S603, following the calculation of time Δt in step S602, a running resistance time change rate α ′ (= ΔFD / Δt) is calculated, and the process proceeds to step S604.

  In step S604, following the calculation of the travel resistance time change rate α ′ in step S603, the vehicle speed is detected from the sensor unit 9 based on the vehicle speed sensor value, and the process proceeds to step S605.

In step S605, following the detection of the vehicle speed in step S604, a specified value Set_dFD that is a threshold value for determining a rapid decrease in running resistance is calculated using the detected vehicle speed and the map shown in FIG. 14, and the process proceeds to step S606.
Here, the map shown in FIG. 14 is based on a large number of experimental data and the like, when the vehicle speed is low, the specified value Set_dFD is increased, and as the vehicle speed becomes higher, the specified value Set_dFD is gradually decreased. Is set as follows.

  In step S606, following the calculation of the prescribed value Set_dFD in step S605, it is determined whether or not the running resistance time change rate α ′ (= ΔFD / Δt) exceeds the prescribed value Set_dFD that is a running resistance sudden decrease determination threshold value. If YES (ΔFD / Δt> Set_dFD), the process proceeds to step S607. If NO (ΔFD / Δt ≦ Set_dFD), the process proceeds to step S608.

  In step S607, “YES” is output based on the determination that the driving resistance suddenly decreases ant following the determination that ΔFD / Δt> Set_dFD in step S606.

In step S608, following the determination that ΔFD / Δt ≦ Set_dFD in step S606, “NO” is output based on the determination that the running resistance has rapidly decreased.
Other configurations are the same as those of the first embodiment shown in FIG. 1, FIG. 2, FIG. 4, and FIG.

Next, the action of detecting a rapid decrease in running resistance in the second embodiment will be described.
FIG. 15 is a time chart showing characteristics of a vehicle driving force, a driving resistance / vehicle acceleration / a driving resistance differential value representing an action of detecting a rapid decrease in driving resistance according to the second embodiment due to a difference in vehicle driving force when stepping on a step. . Hereinafter, the traveling resistance rapid decrease detection operation will be described with reference to FIGS. 4 to 6 and FIG. 15.

  Time t0 in FIG. 15 is a time point at which application of driving force is started by stepping on the accelerator with respect to a step disturbance having a high running resistance. Then, the vehicle driving force is increased by the accelerator depressing operation at time t0, and when the running resistance due to the step disturbance is exceeded at time t1, the electric vehicle 1 starts to move over the step.

  Then, overstepping of the step is started, and while the running resistance time change rate α ′ (= ΔFD / Δt) is equal to or less than the prescribed value Set_dFD that is the running resistance rapid decrease determination threshold, step S501 → step in the flowchart of FIG. It progresses to S502-> step S503-> step S504-> step S506 (running resistance rapid decrease judgment NO). Then, when the running resistance time change rate α ′ (= ΔFD / Δt) reaches a time t2 or a time t4 that exceeds a specified value Set_ΔFD that is a threshold value for judging a sudden decrease in running resistance, in the flowchart of FIG. 6, step S501 → step S502 → The process proceeds from step S503 to step S504 to step S505 (YES in traveling resistance rapid decrease determination).

  Then, in the flowchart of FIG. 4, the process proceeds from step S101 to step S102 to step S103 to step S104. That is, based on the establishment of the travel resistance rapid decrease condition (step S101) and the establishment of the control start condition (step S103), in step S104, the flag is rewritten from OFF to ON, and the driving force suppression control is started.

  Then, from the start time t2 or the start time t4 of the driving force suppression control, the driving force suppression control is maintained while the TCS / ABS stop condition and the Flag = ON condition are satisfied. That is, in the flowchart of FIG. 5, the process of step S201 → step S202 → step S203 → step S204 → step S205 → end is repeated. Then, after overcoming the step, when the time when the braking / driving force target value FC coincides with the driver requested braking / driving force FA is reached, in the flowchart of FIG. 5, step S201 → step S202 → step S203 → step S204 → step S205 → Proceeding to step S206, flag is rewritten from ON to OFF in step S206, and the driving force suppression control is terminated.

  In the detection of this sudden decrease in running resistance, the step ends at time t3 in FIG. 15 when the vehicle driving force is the first driving force FA1. That is, the required time ΔT from the traveling resistance rapid decrease detection time t2 to the step end time t3: FA1 is the required time ΔT from the traveling resistance rapid decrease detection time t2 ′ to the step end time t3 in the comparative example using the vehicle acceleration. ': Longer than FA1.

  Further, in the detection of the sudden decrease in running resistance, the step ends at time t5 in FIG. 15 when the second driving force FA2 has a low vehicle driving force. That is, the required time ΔT from the running resistance rapid decrease detection time t4 to the step end time t5: FA2 is the required time ΔT from the traveling resistance rapid decrease detection time t4 ′ to the step end time t5 in the comparative example using vehicle acceleration. ': Longer than FA2.

In the second embodiment, a configuration is adopted in which a rapid decrease in running resistance is detected when the running resistance time change rate α ′ (= ΔFD / Δt) exceeds a specified value Set_dFD set to a lower value as the vehicle speed increases.
Therefore, regardless of the level of vehicle driving force (or vehicle speed), a rapid decrease in running resistance is detected with high accuracy at an early timing (time t2, t4), and the required time ΔT from the detection of the sudden drop in running resistance to the end of the step. : FA1, ΔT: FA2 is secured for a long time. Then, during the required time ΔT: FA1, ΔT: FA2, by controlling the driving force (or increasing the braking force), it is possible to effectively suppress the rapid acceleration after overcoming the step.
Since other operations are the same as those of the first embodiment, description thereof is omitted.

Next, the effect will be described.
In the control device for the electric vehicle 1 according to the second embodiment, the following effects can be obtained.

(3) The traveling resistance rapid decrease detection means (traveling resistance rapid decrease determination unit 14a) sets the specified value Set_dFD to a lower value as the vehicle speed increases (FIG. 14), and the traveling resistance equivalent value (estimated traveling resistance value FD) When the time change rate (ΔFD / Δt) exceeds the set value Set_dFD, it is detected that the running resistance is rapidly decreasing (step S606 → step S607 in FIG. 13).
For this reason, in addition to the effect of (1) of the first embodiment, the detection of setting the specified value Set_dFD corresponding to the vehicle speed is detected with high accuracy at an early timing regardless of the vehicle speed. can do.

  As mentioned above, although the vehicle control apparatus of the present invention has been described based on the first embodiment and the second embodiment, the specific configuration is not limited to these embodiments, and each claim of the claims Design changes and additions are permitted without departing from the spirit of the invention.

  In the first embodiment, an example in which a sudden decrease in traveling resistance is detected based on a moving distance change rate of the traveling resistance and a threshold value given as a constant value is shown. In the second embodiment, an example is shown in which a rapid decrease in running resistance is detected based on a threshold value given by a lower value as the vehicle speed increases and the time change rate of the running resistance increases. However, it may be an example in which a rapid decrease in travel resistance is detected based on a threshold value given by a lower value as the vehicle driving force is higher as the vehicle driving force is higher. Also, an example of detecting a sudden decrease in running resistance may be detected by using a running resistance time change rate correction value obtained by correcting the time change rate of running resistance by vehicle speed or vehicle driving force and a threshold value given by a constant value.

  In Example 1, the example of control at the time of driving | running | working resistance fall after climbing a level | step difference was shown. However, the control of the present invention can be applied in various ways such as a sudden drop in running resistance when traveling down a steep downhill, a sudden drop in running resistance when receiving a gust of wind from the rear of the vehicle, etc. Even a simple example is included.

  In the first embodiment, an example in which control for converging the actual vehicle driving force to the target vehicle driving force by suppressing the driving force applied to the tire is shown. However, control for converging the actual vehicle driving force to the target vehicle driving force by increasing the braking force applied to the tire may be performed. Further, the control of converging the actual vehicle driving force to the target vehicle driving force may be performed by a combination of suppressing the driving force applied to the tire and increasing the braking force.

  In the first embodiment, the travel resistance calculation unit 12 that calculates the travel resistance estimated value FD is used as the travel resistance equivalent value detection unit. However, as the running resistance equivalent value, for example, if the driving force is considered to be constant, the running resistance may be replaced with the vehicle acceleration.

  In the first embodiment, an example of application to an electric vehicle (EV) has been shown, but also to a hybrid vehicle (HEV), a fuel cell vehicle (FCV), and an internal combustion engine vehicle (gasoline engine vehicle, diesel engine vehicle, etc.). Can be applied.

1 Electric vehicle (an example of a vehicle)
2 Drive motor 3 Braking device 4FL Left front wheel tire (tire)
4FR Right front wheel tire
4RL Left rear wheel tire (tire)
4RR Right rear wheel tire (tire)
5 Electronic control unit (vehicle driving force control means)
6 TCS / ABS controller 7 Accelerator opening sensor 8 Brake operation amount sensor 9 Sensor unit 10 Vehicle speed sensor 11 Driver required driving force required braking force calculation unit 12 Travel resistance calculation unit 13 Target driving force generation unit 14 Control start / end determination unit 14a Traveling resistance rapid decrease determination unit (traveling resistance rapid decrease detection means)
15 Target driving force switching part

Claims (3)

Running resistance equivalent value detecting means for detecting a running resistance equivalent value due to disturbance during vehicle running;
Based on the time change rate of the running resistance equivalent value and the integral element of the vehicle acceleration, a running resistance sudden drop detecting means for detecting a sudden drop in running resistance during vehicle running;
Vehicle driving force control means for starting control by at least one of driving force suppression and braking force increase applied to the tire when a sudden decrease in traveling resistance is detected by the traveling resistance rapid decrease detection means;
A vehicle control device comprising: The vehicle control device according to claim 1,
The vehicle resistance control device is characterized in that when the rate of change of the running resistance equivalent value with respect to the moving distance exceeds a predetermined value, the running resistance rapid drop detection means detects that the running resistance is suddenly reduced. The vehicle control device according to claim 1,
The traveling resistance rapid decrease detecting means sets a specified value to a lower value as the vehicle speed is higher, and detects that the traveling resistance is rapidly decreased when a time change rate of the traveling resistance equivalent value exceeds a specified value. A control apparatus for a vehicle.