JP6225563B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device that controls the braking force of each wheel so as to keep the vehicle body speed low.

  Conventionally, there has been proposed a vehicle control device that performs control to keep the vehicle body speed at a low speed by controlling the braking force of each wheel (see, for example, Patent Document 1). For example, to control vehicle speed at a low speed, the vehicle speed on road surfaces that require speed adjustment, such as off-road such as sand, dirt, rocky roads, snowy roads, and steep slopes, is called crawl control. Control for maintaining the vehicle speed at a constant speed, and control for maintaining the vehicle body speed at a constant speed on a downhill road called DAC (Downhill Assist Control). For example, in crawl control and downhill assist control, the vehicle body speed is kept low by feedback controlling the braking force of each wheel based on the deviation between the target speed and the vehicle body speed.

Japanese Patent Laid-Open No. 2004-90679

  Like crawl control and downhill assist control, high responsiveness is required in the low-speed region, so it is necessary to quickly increase the wheel cylinder (hereinafter referred to as W / C) pressure. For example, when traveling off-road, the W / C pressure can be increased more quickly because frequent occurrence of a sudden change in the slope or road surface of the vehicle and a sudden change in the vehicle's driving state occurs. It is desirable.

  However, in the conventional method in which the braking force of each wheel is feedback-controlled based on the deviation between the target speed and the vehicle body speed, the target braking force cannot be changed in accordance with the change in the running state of the vehicle. The driver may not be able to respond sufficiently and may make the driver feel uncomfortable. In particular, when a brake system having a high boosting capability such as a hydro booster is used, the W / C pressure can be quickly boosted. However, when a system with a low boosting capability is used, the W It is difficult to increase the / C pressure. For this reason, generating a delay in boosting the W / C pressure gives the driver a sense of incongruity due to a delay in applying the brake, and the braking force varies due to a delay in boosting the W / C pressure or a delay in removing the W / C pressure. Thus, speed hunting in which the vehicle body speed fluctuates around the target speed may occur.

  The present invention has been made in view of the above points, and it is an object of the present invention to provide a vehicle control device that can alleviate a driver's uncomfortable feeling when performing control to maintain the vehicle body speed at a low speed by controlling the braking force of each wheel. And

  In order to achieve the above object, according to the first aspect of the present invention, the feedback braking force is calculated based on the deviation between the vehicle body speed and the target speed every predetermined control period, and the feedback braking force is generated to generate the vehicle body. When it is determined to be an overspeed state, a feedback control unit that performs feedback control to bring the speed close to the target speed, an overspeed state determination unit that determines whether the vehicle body speed exceeds the target speed, or an overspeed state determination unit Correction means for correcting the feedback braking force so that the feedback braking force rises faster with respect to the deviation between the vehicle body speed and the target speed than in a normal driving state that is not determined as the overspeed state. It is characterized by that.

  As described above, when it is determined that the vehicle is in the overspeed state, the feedback braking force increases with respect to the deviation between the vehicle body speed and the target speed in comparison with the normal driving state that is not determined to be the overspeed state. The feedback braking force is corrected. That is, the feedback braking force is corrected in a feedforward manner. For this reason, the vehicle body speed can be made to follow the target speed, and the deviation between the vehicle body speed and the target speed can be reduced. Therefore, it is possible to obtain high responsiveness, and it is possible to further alleviate the driver's uncomfortable feeling when performing control to keep the vehicle body speed low.

According to the first aspect of the present invention, the target acceleration / deceleration is calculated based on the deviation between the vehicle body speed and the target speed, and the target deceleration force that is a braking force necessary to generate the target acceleration / deceleration is calculated. A target deceleration force calculation means, and the correction means is determined to be in an overspeed state, and when the previous value, which is the feedback braking force in the previous control cycle, is smaller than the target deceleration force, feedback in the current control cycle When calculating the braking force, the feedback braking force is corrected by adding a correction value based on the target deceleration force to the previous value.

  As described above, when the previous value of the feedback braking force is smaller than the target deceleration force, a correction value based on the target deceleration force, for example, a value obtained by multiplying the target deceleration force by the adaptation constant is added as a correction value to the previous value of the feedback braking force. To do. As a result, high responsiveness can be obtained, and it is possible to further alleviate the driver's uncomfortable feeling when performing control to keep the vehicle body speed low.

In the invention according to claim 2 , acceleration acquisition means for acquiring vehicle body acceleration which is acceleration in the longitudinal direction of the vehicle body, acceleration determination means for determining whether the vehicle is accelerating based on the vehicle body acceleration, vehicle An inclination acquisition means for acquiring the inclination of the running road surface, and the correction means is determined to be in an overspeed state, and if the vehicle is determined to be accelerating, the vehicle is on an inclined slope. The feedback braking force is corrected to the greater of the value obtained by adding a predetermined braking force to the required braking force on the slope, which is the braking force necessary for stopping, and the feedback braking force, whichever is greater Yes.

  As described above, when it is determined that the vehicle is in an overspeed state and the vehicle is determined to be accelerating, a predetermined braking force is applied to the braking force required for the slope, which is a braking force necessary for the vehicle to stop on a slope with a slope. The feedback braking force is corrected to the larger of the value obtained by multiplying the power added by the adaptation constant and the feedback braking force. As a result, in a situation where the acceleration state is desired to be suppressed earlier in the acceleration state in the overspeed state, the feedback braking force can be set in consideration of the necessary braking force on the hill, and higher responsiveness can be obtained.

According to a third aspect of the present invention, there is provided an acceleration acquisition unit that acquires a vehicle body acceleration that is an acceleration in the longitudinal direction of the vehicle body, and an acceleration determination unit that determines whether or not the vehicle is accelerating based on the vehicle body acceleration. And the correction means is adapted to a vehicle body acceleration force which is a braking force necessary to make the vehicle body acceleration zero when it is determined that the vehicle is accelerating when it is determined that the vehicle is in an overspeed state. It is characterized in that the feedback braking force is corrected to the larger one of the value multiplied by and the feedback braking force.

  As described above, when it is determined that the vehicle is in an overspeed state and the vehicle is determined to be accelerating, the vehicle body acceleration force, which is a braking force necessary to reduce the vehicle body acceleration to 0, is multiplied by the adaptation constant. The feedback braking force is corrected to the larger of the value and the feedback braking force. That is, since the vehicle is accelerating even though the target speed is constant, the feedback braking force is corrected so as to eliminate the acceleration. As a result, the feedback braking force is corrected so as to eliminate the vehicle body acceleration, and the vehicle body speed can be made closer to the target speed with higher responsiveness.

According to a fourth aspect of the present invention, there is provided an acceleration acquisition means for acquiring a vehicle body acceleration which is an acceleration in the longitudinal direction of the vehicle body, an acceleration determination means for determining whether or not the vehicle is accelerating based on the vehicle body acceleration, Driving force acquisition means for acquiring the driving force of the vehicle, and the correction means multiplies the driving force by a matching constant when it is determined that the vehicle is accelerating. It is characterized in that the feedback braking force is corrected to the larger one of the measured value and the feedback braking force.

  As described above, when it is determined that the vehicle is in an overspeed state and the vehicle is accelerating, the feedback braking force is increased to the greater of the value obtained by multiplying the driving force by the adaptation constant and the feedback braking force. Correct. As a result, the feedback braking force is corrected so as to eliminate the driving force, and the vehicle body speed can be made closer to the target speed with higher responsiveness.

According to the fifth aspect of the present invention, the acceleration acquisition means for acquiring the vehicle body acceleration which is the longitudinal acceleration of the vehicle body, and the acceleration for determining the acceleration end time from when the vehicle is accelerating to ending the acceleration based on the vehicle body acceleration An end determination unit, and an inclination acquisition unit that acquires an inclination of the traveling road surface of the vehicle. When the correction unit is determined to be in an overspeed state and is determined to be at the end of acceleration of the vehicle, feedback is provided. The feedback braking force is added to the braking force that has a predetermined distribution of the braking force and the value obtained by adding the predetermined braking force to the required braking force that is necessary for stopping the vehicle on a slope with a slope. It is characterized by correcting.

  As described above, when it is determined that the vehicle is in an overspeed state and the vehicle is at the end of acceleration, a feedback braking force and a braking force required for a slope that is a braking force necessary for stopping the vehicle on a slope with a slope. The feedback braking force is corrected to a braking force in which a value obtained by adding the predetermined braking force to a predetermined distribution becomes a predetermined distribution. During the acceleration of the vehicle, the feedback braking force is set to a large value so as to stop the acceleration quickly. Therefore, the feedback braking force is lowered to an appropriate value at the end of the acceleration. Thereby, it is possible to suppress the feedback braking force from becoming a large value until after the vehicle body speed approaches the target speed.

In the invention according to claim 6 , acceleration acquisition means for acquiring vehicle body acceleration which is acceleration in the longitudinal direction of the vehicle body, and rapid deceleration in which the vehicle body deceleration expressed as a negative value of the vehicle body acceleration is less than a predetermined deceleration. A sudden deceleration determining means for determining, a driving force acquiring means for acquiring the driving force of the vehicle, and an inclination acquiring means for acquiring the inclination of the traveling road surface of the vehicle, and the correcting means is determined to be in an overspeed state, If it is determined that the vehicle is suddenly decelerating, the driving force against the value obtained by adding a predetermined braking force to the braking force required for stopping on the slope where the vehicle is inclined and the driving force The feedback braking force is corrected to the largest value among the value obtained by multiplying the adaptation constant and the output lower limit value of the feedback braking force.

  In this way, when the vehicle is decelerating suddenly, a value obtained by adding a predetermined braking force to the required braking force on the slope, which is a braking force necessary for the vehicle to stop on an inclined slope, and driving The feedback braking force is corrected to the largest value among the value obtained by multiplying the force by the adaptation constant and the output lower limit value of the feedback braking force. Thereby, it is possible to prevent the feedback braking force from becoming a large value when the vehicle is decelerating rapidly.

1 is a diagram illustrating a system configuration of a braking / driving system of a vehicle to which a vehicle control device according to a first embodiment of the present invention is applied. FIG. 6 is a diagram illustrating an example of a relationship between a deviation between a target speed TBV and a vehicle body speed V0 and a distribution K3 of a feedback braking force FBbrakeForce. FIG. 5 is a diagram showing an example of a relationship between a deviation between a target speed TBV and a vehicle body speed V0 and a deviation speed V1. It is the flowchart which showed the whole crawl control including TRC. It is the flowchart which showed the whole crawl control including TRC following Fig.4 (a). It is the flowchart which showed the detail of the calculation process of the feedback braking force FBbrakeForce corrected in feedforward. It is a time chart at the time of performing the conventional feedback control. It is a time chart at the time of performing feedback control concerning a 1st embodiment. It is a time chart at the time of performing feedback control concerning a 1st embodiment. It is a time chart at the time of performing feedback control concerning a 1st embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
FIG. 1 is a diagram showing a system configuration of a braking / driving system of a vehicle to which a vehicle control device according to a first embodiment of the present invention is applied. Here, a case where the vehicle control device according to an embodiment of the present invention is applied to a front drive-based four-wheel drive vehicle in which the front wheel side is a main drive wheel and the rear wheel side is a slave drive wheel will be described. However, the present invention can also be applied to a rear drive base four-wheel drive vehicle in which the rear wheel side is a main drive wheel and the front wheel side is a slave drive wheel.

  As shown in FIG. 1, the drive system of a four-wheel drive vehicle includes an engine 1, a transmission 2, a driving force distribution control actuator 3, a front propeller shaft 4, a rear propeller shaft 5, a front differential 6, a front drive shaft 7, It has a configuration including a differential 8 and a rear drive shaft 9, and is controlled by an engine ECU 10 serving as engine control means.

  Specifically, when the operation amount of the accelerator pedal 11 is input to the engine ECU 10, the engine control is performed by the engine ECU 10, and the engine output (engine torque required for generating the driving force corresponding to the accelerator operation amount) ) Is generated. The engine output is transmitted to the transmission 2 and converted by a gear ratio corresponding to the gear position set in the transmission 2, and then transmitted to the driving force distribution control actuator 3 serving as driving force distribution control means. The transmission 2 includes a transmission 2a and a sub-transmission 2b. During normal traveling, an output corresponding to the gear position set by the transmission 2a is transmitted to the driving force distribution control actuator 3, and during off-road traveling. When the sub-transmission 2b is operated during traveling on a slope or the like, an output corresponding to the gear position set by the sub-transmission 2b is transmitted to the driving force distribution control actuator 3. The driving force is transmitted to the front propeller shaft 4 and the rear propeller shaft 5 in accordance with the driving force distribution determined by the driving force distribution control actuator 3.

  Thereafter, a driving force according to the driving force distribution on the front wheel side is applied to the front wheels FR and FL through the front drive shaft 7 connected to the front propeller shaft 4 via the front differential 6. A driving force according to the driving force distribution on the rear wheel side is applied to the rear wheels RR and RL through a rear drive shaft 9 connected to the rear propeller shaft 5 via a rear differential 8.

  The engine ECU 10 is configured by a known microcomputer including a CPU, ROM, RAM, I / O, and the like, and performs various calculations and processes according to a program stored in the ROM or the like, thereby generating engine output (engine torque). And the driving force generated in each wheel FL to RR is controlled. For example, the engine ECU 10 inputs an accelerator opening by a known method, and calculates an engine output based on the accelerator opening and various engine controls. The engine ECU 10 outputs a control signal to the engine 1 to adjust the fuel injection amount and control the engine output. The engine ECU 10 can determine that the accelerator pedal 11 is on when the accelerator opening exceeds the accelerator-on threshold, but in this embodiment, an accelerator indicating whether or not the accelerator pedal 11 is being operated. A switch 11a is provided, and it is detected that the accelerator pedal 11 is turned on by inputting a detection signal of the accelerator switch 11a. The engine ECU 10 also executes traction control (hereinafter referred to as TRC). For example, the engine ECU 10 acquires information on wheel speed and vehicle body speed (estimated vehicle body speed) from a brake ECU 19 described later, and outputs a control signal to the brake ECU 19 so that acceleration slip represented by these deviations is suppressed. The driving force is reduced by applying a braking force to the wheel to be controlled. Thereby, acceleration slip is suppressed and the vehicle can be accelerated efficiently.

  Although not shown here, the transmission 2 is controlled by the transmission ECU, and the driving force distribution control is performed by the driving force distribution ECU or the like. These ECUs and the engine ECU 10 exchange information with each other through the in-vehicle LAN 12. In FIG. 1, information on the transmission 2 is directly input to the engine ECU 10. For example, gear position information of the transmission 2 output from the transmission ECU is input to the engine ECU 10 through the in-vehicle LAN 12. May be.

  On the other hand, the service brake constituting the braking system includes a brake pedal 13, a master cylinder (hereinafter referred to as M / C) 14, a brake actuator 15, a wheel cylinder (hereinafter referred to as W / C) 16FL to 16RR, a caliper 17FL to 17RR, The disc rotors 18FL to 18RR are configured, and are controlled by a brake ECU 19 serving as brake control means.

  Specifically, when the brake pedal 13 is depressed and operated, a brake fluid pressure is generated in the M / C 14 in accordance with the amount of brake operation, and the brake hydraulic pressure is generated via the brake actuator 15 from W / C16FL to 16RR. To be told. Accordingly, the disc rotors 18FL to 18RR are sandwiched by the calipers 17FL to 17RR, so that a braking force is generated. The service brake having such a configuration may be any one as long as it can automatically pressurize W / C 16FL to 16RR. Here, a hydraulic service brake that generates W / C pressure by hydraulic pressure is taken as an example. However, it may be an electric service brake such as a brake-by-wire that electrically generates a W / C pressure.

  The brake ECU 19 is configured by a known microcomputer including a CPU, ROM, RAM, I / O, and the like, and executes various calculations and processes according to a program stored in the ROM or the like to thereby apply a braking force (braking torque). And the braking force generated in each of the wheels FL to RR is controlled. Specifically, the brake ECU 19 receives detection signals from the wheel speed sensors 20FL to 20RR provided in the wheels FL to RR, calculates various physical quantities such as the wheel speed and the vehicle body speed, A detection signal is input, and brake control is performed based on a physical quantity calculation result and a brake operation state. The brake ECU 19 receives the detection signal of the M / C pressure sensor 22 and detects the M / C pressure.

  The brake ECU 19 also performs crawl control, which is vehicle control in off-road, etc., based on the control of the braking force. Specifically, the brake ECU 19 inputs a detection signal of the crawl switch 23 and the target speed setting switch 24 that are operated when the driver requests crawl control, and a detection signal of the acceleration sensor 25 that detects longitudinal acceleration. Crawl control is executed based on the detection signal. The crawl switch 23 is basically considered to be pressed when performing off-road traveling, but the same control is performed even when pressed on a steep slope. The target speed setting switch 24 is used for setting a target speed when the crawl control is executed, and sets the target speed in a speed range of 1 to 5 km / h, for example. In FIG. 1, detection signals from the M / C pressure sensor 22 and the acceleration sensor 25 are input to the brake ECU 19 via the brake actuator 15, but are configured to be input directly from each sensor to the brake ECU 19. It may be.

  As described above, the vehicle braking / driving system system to which the vehicle control device according to the present embodiment is applied is configured. Next, the operation of the vehicle control device configured as described above will be described. In the vehicle control device according to the present embodiment, normal engine control and brake control are also performed as vehicle control. However, since these are the same as conventional ones, crawl control related to features of the present invention will be described here. To do. In the case of the present embodiment, the brake control of the crawl control is executed as the vehicle control, and the brake ECU 19 executes the control. Therefore, the brake ECU 19 constitutes a vehicle control device.

  The crawl control is executed when the driver depresses the crawl switch 23, sets the target speed TBV with the target speed setting switch 24, and makes a crawl control execution request. In the vehicle control apparatus according to the present embodiment, as the crawl control, when the driver sets the target speed TBV, feedback control is performed by setting the control amount of the brake control based on the deviation between the vehicle body speed V0 and the target speed TBV. In addition to the above, processing is performed to improve responsiveness. The target speed TBV can be set by the driver as the crawl switch 23 is operated, and can be arbitrarily set in a speed range of 1 to 5 km / h, for example. The vehicle body speed V0 is calculated by the brake ECU 19, and is calculated by a well-known method based on the wheel speeds obtained from the detection signals of the wheel speed sensors 20FL to 20RR provided in the wheels FL to RR. Basically, based on the deviation between the vehicle speed V0 and the target speed TBV, the control amount of the feedback control increases as the vehicle speed V0 becomes larger than the target speed TBV so that the vehicle speed V0 approaches the target speed TBV. It is trying to become.

  However, if the vehicle's running condition suddenly changes due to a sudden change in the slope or road condition of the vehicle, such as when driving off-road, the responsiveness will be adjusted to the sudden change in the driving condition. It is desirable to change the target braking force well so that the W / C pressure can be increased more quickly. For this reason, in simple feedback control, the target braking force cannot be changed in accordance with the change in the running state of the vehicle, and the driver cannot respond sufficiently, giving the driver a sense of incongruity. If the control amount in feedback control is set large, high responsiveness can be obtained, but the vehicle speed V0 constantly increases and decreases around the target speed TBV and frequent acceleration / deceleration is repeated. It is not preferable to increase. For this reason, by performing control for correcting the control amount of the feedback control in a feed-forward manner as described below, the driver's uncomfortable feeling can be alleviated. In this specification, a feedback braking force is described as a control amount of brake control by feedback control, but a braking torque is assumed as the feedback braking force. However, another control amount that can be used as a control amount corresponding to the braking torque, such as a W / C pressure, may be used.

  First, the normal driving state and the overspeed state are determined. When it is determined that the vehicle is in the overspeed state, the braking torque by the feedback control increases more quickly in the overspeed state than in the normal driving state. Correct as follows. Specifically, the following controls (1) to (6) are executed.

  (1) In the overspeed state, the previous value (hereinafter referred to as feedback braking force FBbrakeForce) of the braking force generated by feedback control (hereinafter referred to as feedback braking force FBbrakeForce) is required to generate the target acceleration / deceleration. If the braking force is smaller than the target braking force (hereinafter referred to as the target deceleration force TBDV), a value obtained by multiplying the target deceleration force TBDV by the adaptation constant K1 (for example, 0.2) is added to the feedback braking force FBbrakeForce (previous value) as a correction value. . The target acceleration / deceleration is a differential value of the target vehicle speed determined based on the deviation between the target speed TBV and the vehicle speed V0 in feedback control. When the vehicle speed V0 is brought close to the target speed TBV, how much acceleration / deceleration is used. It is the target value that determines whether to approach. As the deviation between the target speed TBV and the vehicle body speed V0 is larger, the target acceleration / deceleration is set to a larger value, and the vehicle body speed V0 is brought closer to the target speed TBV earlier in a feedforward manner. As a result, high responsiveness can be obtained, and the driver's uncomfortable feeling can be further alleviated when performing control to keep the vehicle body speed V0 at a low speed.

  (2) When the vehicle is accelerating in an overspeed condition, the correction value based on the slope of the road surface, that is, the braking force necessary for stopping on a slope with a slope (hereinafter referred to as the slope required braking slope) BrakeSlopeForce A value obtained by multiplying a value obtained by adding the constant braking force α1 (for example, 500 N) to the adaptation constant K2 (for example, 1.1) is compared with the feedback braking force FBbrakeForce, and the larger one is set as the provisional feedback braking force FBbrakeForce. As a result, in a situation where the acceleration state is desired to be suppressed earlier in the acceleration state in the overspeed state, the feedback braking force can be set in consideration of the necessary braking force on the hill, and higher responsiveness can be obtained. At this time, you may simply compare the required braking force BrakeSlopeForce with the feedback braking force FBbrakeForce, but since it is in an overspeed state, the necessary braking force FBbrakeForce is set to a higher value. A value obtained by multiplying a value obtained by adding a predetermined braking force α1 to the power BrakeSlopeForce and a matching constant K2 (for example, 1.1) is compared with the feedback braking force FBbrakeForce. If the required braking force BrakeSlopeForce is simply compared with the feedback braking force FBbrakeForce, the adaptation constant K2 may be set to 1. Further, the predetermined braking force α1 may be set to an arbitrary value because it is a compatible constant, but is set to a value that considers variations of the acceleration sensor 25 and the like.

  The reason why such a correction value based on the road surface inclination is necessary is considered to be from the time when the vehicle stops to the time when the vehicle shifts to stable running. Therefore, the above correction may be performed until a predetermined period elapses after the vehicle stops, for example, until one second elapses, and the correction may not be performed after the predetermined period elapses.

  (3) When the vehicle is accelerating in the overspeed state, the adaptation constant K2 (for example, 1.1) is applied to the vehicle body acceleration force DV0Force corresponding to the braking force required to make the vehicle body acceleration DV0 zero based on the vehicle body acceleration DV0. ) Is compared with the feedback braking force FBbrakeForce, and the larger one is set as the provisional feedback braking force FBbrakeForce. That is, since the vehicle is accelerating even though the target speed TBV is constant, the feedback braking force FBbrakeForce is corrected so as to eliminate the acceleration. As a result, the feedback braking force FBbrakeForce is corrected so as to eliminate the vehicle body acceleration DV0, and the vehicle body speed V0 can approach the target speed TBV with higher responsiveness. Even at this time, you may simply compare the vehicle acceleration force DV0Force with the feedback braking force FBbrakeForce, but because it is in an overspeed state, the vehicle acceleration is set so that the feedback braking force FBbrakeForce is set to a higher value. The value obtained by multiplying the force DV0Force by the adaptation constant K2 is compared with the feedback braking force FBbrakeForce. If the vehicle acceleration force DV0Force is simply compared with the feedback braking force FBbrakeForce, the adaptation constant K2 may be set to 1.

  (4) When the vehicle is accelerating in the overspeed state, the value obtained by multiplying the driving force DriveForce by the adaptation constant K2 (for example, 1.1) is compared with the feedback braking force FBbrakeForce, and the larger one is the provisional feedback braking force. Set to FBbrakeForce. In other words, since the vehicle is accelerated by the engine torque, it is necessary to generate a braking force equivalent to the driving force DriveForce in order to reduce the driving force DriveForce to 0. Therefore, the feedback braking force FBbrakeForce and the driving force DriveForce are set to a constant constant K2. The larger of the multiplied values is set as the temporary feedback braking force FBbrakeForce. As a result, the feedback braking force FBbrakeForce is corrected so as to eliminate the driving force DriveForce, and the vehicle body speed V0 can approach the target speed TBV with higher responsiveness. At this time, the drive force DriveForce may be simply compared with the feedback braking force FBbrakeForce, but since it is in an overspeed state, the driving force DriveForce is set so that the feedback braking force FBbrakeForce is set to a higher value. Is compared with the feedback braking force FBbrakeForce. If the drive force DriveForce is simply compared with the feedback braking force FBbrakeForce, the adaptation constant K2 may be set to 1.

  (5) When the vehicle finishes accelerating in the overspeed state, that is, when the vehicle body acceleration is greater than 0 and becomes less than or equal to 0, the predetermined braking force is applied to the feedback braking force FBbrakeForce (previous value) and the necessary braking force BrakeSlopeForce. A braking force in which a value obtained by adding α1 (for example, 500 N) is a predetermined distribution is set as a provisional feedback braking force FBbrakeForce. As described above, during the acceleration of the vehicle, the feedback braking force FBbrakeForce is set to a large value so as to quickly stop the acceleration. Therefore, the feedback braking force FBbrakeForce is lowered to an appropriate value at the end of the acceleration. As a result, the feedback braking force FBbrakeForce can be prevented from becoming a large value until the vehicle body speed V0 approaches the target speed TBV. However, since the acceleration of the vehicle has ended and the provisional feedback braking force FBbrakeForce is smaller than the feedback braking force FBbrakeForce (previous value), the feedback braking force FBbrakeForce (previous value) is set to the upper limit value. Yes.

  The predetermined distribution here is obtained by a deviation between the vehicle body speed V0 and the target speed TBV. If the distribution of the feedback braking force FBbrakeForce is K3, the predetermined braking force α1 is added to the slope required braking force BrakeSlopeForce. The distribution is (1−K3).

  Each distribution K3, (1−K3) may be basically set to a value corresponding to the deviation between the vehicle speed V0 and the target speed TBV, but the vehicle body according to the set target speed TBV. It is preferable to change each distribution K3, (1-K3) according to the deviation between the speed V0 and the target speed TBV. That is, even if the deviation between the vehicle body speed V0 and the target speed TBV is the same value, the driver's feeling changes according to the target speed TBV. For example, when the target speed TBV is set to 5 km / h, even if a deviation of 1 km / h between the vehicle speed V0 and the target speed TBV occurs, the driver does not feel strange, but the target speed TBV is 1 km / h. When the deviation between the vehicle speed V0 and the target speed TBV occurs at 1 km / h, the driver feels uncomfortable. For this reason, the deviation speed V1 corresponding to the target speed TBV is set, the distribution speed K3 of the feedback braking force FBbrakeForce is obtained using this deviation speed V1, and the slope required braking force BrakeSlopeForce based on the distribution K3 of this feedback braking force FBbrakeForce. Distribution (1-K3) is obtained for a value obtained by adding a predetermined braking force α1 to.

  FIG. 2 is a diagram showing an example of the relationship between the deviation between the vehicle body speed V0 and the target speed TBV and the distribution K3 of the feedback braking force FBbrakeForce. FIG. 3 is a diagram showing an example of the relationship between the deviation between the vehicle body speed V0 and the target speed TBV and the deviation speed V1.

  First, as shown in FIG. 3, the deviation speed V1 is set according to the target speed TBV. Specifically, the larger the target speed TBV is, the larger the deviation speed V1 is. In the case of this embodiment, the deviation speed V1 is increased in direct proportion to the target speed TBV. Yes. Then, the deviation speed V1 obtained in this way is set as the upper limit value of the deviation between the vehicle body speed V0 and the target speed TBV, and the deviation from a predetermined speed (for example, 0.5 km / h in FIG. 2) as shown in FIG. In the speed range up to the speed V1, a distribution K3 of the feedback braking force FBbrakeForce corresponding to the deviation between the vehicle body speed V0 and the target speed TBV is obtained. For example, in FIG. 2, the distribution K3 is variable in the range of 0.0 to 0.8 in the variation range of the deviation between the vehicle speed V0 and the target speed TBV. The distribution K3 of the feedback braking force FBbrakeForce increases as the deviation increases.

  (6) When the vehicle decelerates suddenly in an overspeed state, for example, the vehicle body deceleration is less than a predetermined deceleration, a predetermined adaptation to the value obtained by adding the predetermined braking force α1 to the required braking force BrakeSlopeForce and the driving force DriveForce A correction value T1 is the largest value among the three correction values multiplied by a constant K4 (for example, 0.5) and the correction value α2 that is the output lower limit value of the feedback braking force FBbrakeForce. The correction value T1 is set as a temporary feedback braking force FBbrakeForce. Thereby, when the vehicle is decelerating rapidly, the feedback braking force FBbrakeForce can be prevented from becoming too large. However, since the vehicle is decelerating rapidly and the current feedback braking force FBbrakeForce is smaller than the feedback braking force FBbrakeForce (previous value), the feedback braking force FBbrakeForce (previous value) is set to the upper limit value. That is, the correction value T1 is compared with the feedback braking force FBbrakeForce (previous value), and the smaller one is set as the current feedback braking force FBbrakeForce.

  Thereby, when the vehicle is decelerating more than expected, the feedback braking force FBbrakeForce is further reduced. In other words, if the correction value T1 is larger than the feedback braking force FBbrakeForce, it will not be possible to release the brake further, so the smaller of the correction value T1 and the feedback braking force FBbrakeForce (previous value) The braking force is FBbrakeForce.

  As described above, when the crawl control is executed, the above-described controls (1) to (6) are executed. Next, details of the crawl control executed in this way will be described. 4A and 4B are flowcharts showing the entire crawl control including the TRC. The details of the crawl control including the TRC will be described below with reference to this figure.

  First, in step 100, various input processes are performed. Specifically, by inputting the detection signals of the wheel speed sensors 20FL to 20RR and the detection signal of the acceleration sensor 25, the wheel speed VW ** of each wheel FL to RR is calculated and the longitudinal acceleration Gx of the vehicle is calculated. To do. The subscript ** attached to the wheel speed VW ** indicates any of FL to RR, and VW ** is a comprehensive description of the wheel speed of each corresponding wheel FL to RR. is there. In the following description, it is assumed that the subscript ** indicates any of FL to RR.

  In addition, the detection signal of the M / C pressure sensor 22 is input to detect the M / C pressure, or the accelerator opening, the driving force, the gear position of the auxiliary transmission 2b, that is, whether it is located at H4 or L4. Is input from the engine ECU 10 or the like through the in-vehicle LAN 12. Further, detection signals from the crawl switch 23 and the target speed setting switch 24 are input to detect whether or not the driver is requesting crawl control and selecting a target speed.

  Next, the routine proceeds to step 105, where it is determined whether or not the crawl control execution condition is satisfied. Specifically, the gear position of the sub-transmission 2b is set to L4, that is, the gear ratio of the low-speed gear used for off-road or the like. It is determined whether the crawl switch 23 is turned on. Here, if the determination is affirmative, the execution condition for crawl control is satisfied, and therefore the process proceeds to step 110 to set a flag indicating permission for crawl control. If the determination is negative, the execution condition for crawl control is not satisfied. Proceed to, and set a flag indicating that crawl control is prohibited.

  Subsequently, the routine proceeds to step 120, where the vehicle body speed V0 is calculated based on each wheel speed VW **. In step 125, the vehicle body speed DV0 is calculated by time differentiation of the vehicle body speed V0. Then, the process proceeds to step 130, and the vehicle body acceleration force DV0Force corresponding to the braking force required to make the vehicle body acceleration DV0 zero is calculated. For example, the vehicle body acceleration force DV0Force can be calculated based on the vehicle body acceleration DV0 and the vehicle weight determined for each vehicle. In step 135, the driving force DriveForce is calculated. For example, the value acquired by the input process in step 100 can be used. Further, in the input process, instead of directly inputting the driving force DriveForce, engine torque information and a gear ratio may be input, and the driving force DriveForce may be calculated from these and the tire diameter.

Then, it progresses to step 140 and calculates slope slope SLOPE. First, since the difference between the vehicle body acceleration DV0 and the longitudinal acceleration Gx of the vehicle calculated based on the detection signal of the acceleration sensor 25 in step 100 corresponds to the gravitational acceleration component, the slope gradient SLOPE = sin ⁻¹ {(Gx−DV0 ) /9.8} is used to calculate the slope gradient SLOPE. Then, the process proceeds to step 145, and on the basis of the slope gradient SLOPE calculated in step 140, the slope required braking force BrakeSlopeForce necessary for preventing the vehicle from sliding down on the slope slope SLOPE is calculated. For example, the required braking force BrakeSlopeForce can be calculated based on the slope SLOPE and the vehicle weight.

  Subsequently, the routine proceeds to step 150, where the braking force FOOTBRAKE by the driver's braking operation is calculated. For example, based on the M / C pressure input at step 100, the braking force FOOTBRAKE corresponding to the M / C pressure is calculated. Since the relationship between the M / C pressure and the braking force FOOTBRAKE can be examined in advance by experiments, a map showing the relationship is created and the braking force FOOTBRAKE corresponding to the M / C pressure is used using the map. Can be calculated.

  In step 155, the target speed TBV is calculated. The target speed TBV is basically a speed within a speed range (for example, 1 to 5 km / h) set by the driver with the target speed setting switch 24, but when the driver switches the target speed TBV. Instead of suddenly changing to the target speed TBV after switching, a filter is applied so that the target speed TBV before switching is gradually changed to the target speed TBV after switching. For example, the target speed TBV before switching is changed with a constant gradient from the target speed TBV after switching to the target deceleration (or target acceleration). Then, the process proceeds to step 160, and the target deceleration force TBDV is calculated. For example, the target deceleration force TBDV can be calculated based on the differential value of the target speed TBV and the vehicle weight.

  In this way, when the calculation of various parameters is completed, it is determined in step 165 whether or not crawl control is prohibited. If it is prohibited, the feedback braking force FBbrakeForce in the feedback calculation is set to 0 [N] in step 170, and the target pressure TargetPress ** of the W / C pressure of each wheel FL to RR is set to 0 [MPa in step 175. ] To prevent crawling control, and if not prohibited, the process proceeds to step 180.

  In step 180, a process of calculating a feedback braking force FBbrakeForce corrected in a feed-forward manner by the controls (1) to (6) described above is performed. FIG. 5 is a flowchart showing details of this processing.

  First, in step 180a, it is determined whether or not it is an overspeed state. Here, it is determined that the vehicle is in an overspeed state when the vehicle body speed V0 exceeds the target speed TBV. If an affirmative determination is made here, the processing after step 180b is executed to perform a process for correcting the feedback braking force FBbrakeForce in a feedforward manner, and if a negative determination is made, the processing is terminated.

  In steps 180b to 180d, the above-described control (1) is performed. Specifically, in step 180b, it is determined whether or not the feedback braking force FBbrakeForce (previous value) is smaller than the target deceleration force TBDV. If an affirmative determination is made, the routine proceeds to step 180c, where a value obtained by adding a value obtained by multiplying the feedback braking force FBbrakeForce (previous value) by the target deceleration force TBDV and the adaptation constant K1 (for example, 0.2) is provisional feedback control. Power FBbrakeForce. At this time, the target deceleration force TBDV may be used as the correction value as it is, but a value obtained by multiplying the target deceleration force TBDV by the adaptation constant K1 is used as the correction value. The adaptation constant K1 may be a constant value, but in order not to become a transiently large value, for example, as the difference between the feedback braking force FBbrakeForce (previous value) and the target deceleration force TBDV increases, it gradually increases. Also good.

  The braking force required to generate the target acceleration / deceleration is set as the target deceleration force, which is set as TBDV. However, the value obtained by multiplying the target deceleration differential value by the vehicle weight is subtracted from the target deceleration force. A value obtained by adding the necessary braking force BrakeSlopeForce may be used as a TBDV with a slope added.

  On the other hand, if a negative determination is made in step 180b, the routine proceeds to step 180d, where the feedback braking force FBbrakeForce (previous value) is set as it is as the temporary feedback braking force FBbrakeForce without being corrected.

  Subsequently, the routine proceeds to step 180e, where it is determined whether or not the vehicle is accelerating, that is, whether or not the vehicle body acceleration DV0 is positive (> 0G). If an affirmative determination is made here, the vehicle is accelerating, so the routine proceeds to steps 180f to 180i to perform the controls (2) to (4) described above.

  Specifically, in step 180f, the period during which the vehicle body speed V0 exceeds 0 km / h is a predetermined period (for example, 1 second here), that is, the period after the vehicle has stopped moving to the predetermined period has elapsed. If the determination is affirmative, the process proceeds to step 180g and the control (2) is performed. That is, in step 180g, a value obtained by adding a value obtained by multiplying a predetermined braking force α1 by a conforming constant K2 (for example, 1.1) to a required braking force BrakeSlopeForce on a slope is compared with a feedback braking force FBbrakeForce, whichever is greater. Set to provisional feedback braking force FBbrakeForce. At this time, a value obtained by adding the predetermined braking force α1 to the required braking force BrakeSlopeForce may be used as a correction value as it is. However, for example, a predetermined braking force α1 with respect to the required braking force BrakeSlopeForce is considered in consideration of variations in vehicle weight. A value obtained by multiplying the value obtained by multiplying the value by the adaptation constant K2 is used as a correction value.

  Next, in step 180h, as the control in (3) described above, a value obtained by multiplying the vehicle body acceleration force DV0Force by the adaptation constant K2 (for example, 1.1) is compared with the feedback braking force FBbrakeForce, and the larger one is temporarily set. Set to feedback braking force FBbrakeForce. At this time, the vehicle acceleration force DV0Force may be used as a correction value as it is, but for example, taking into account variations in the vehicle weight, the value obtained by multiplying the vehicle acceleration force DV0Force by the adaptation constant K2 (eg 1.1) is used as the correction value. .

  In step 180i, as the control of (4) described above, the value obtained by multiplying the driving force DriveForce by the adaptation constant K2 (for example, 1.1) is compared with the feedback braking force FBbrakeForce, and the larger one is provisional feedback control. Set to power FBbrakeForce. At this time, the driving force DriveForce may be used as the correction value as it is. However, for example, in consideration of variations in vehicle weight, the value obtained by multiplying the driving force DriveForce by the adaptation constant K2 is used as the correction value. Thus, when the vehicle is accelerating in the overspeed state, the above-described controls (2) to (4) are executed to correct the feedback braking force FBbrakeForce.

  On the other hand, if it is determined in step 180e that the vehicle is not accelerating but a negative determination is made, the process proceeds to step 180j to determine whether or not the vehicle has been accelerated. Here, by determining whether or not the vehicle body acceleration DV0 in the previous control cycle is positive (> 0G), it is determined whether or not the vehicle has been accelerated. If an affirmative determination is made here, the routine proceeds to step 180k, and as the control of (5) described above, the feedback braking force FBbrakeForce (previous value) and a value obtained by adding the predetermined braking force α1 to the slope required braking force BrakeSlopeForce are predetermined. The braking force that results in the distribution of is assumed to be a provisional feedback braking force FBbrakeForce. Specifically, after calculating the distribution K3 of the feedback braking force FBbrakeForce based on FIG. 2 and FIG. 3, the distribution for the value obtained by adding the predetermined braking force α1 to the required braking force BrakeSlopeForce based on this distribution K3 Find (1-K3). Then, add the value obtained by multiplying the feedback braking force FBbrakeForce (previous value) by the distribution K3 and the value obtained by adding the predetermined braking force α1 to the necessary braking force BrakeSlopeForce and the value obtained by multiplying the distribution (1−K3). Therefore, the provisional feedback braking force FBbrakeForce is being sought. However, since the acceleration of the vehicle has ended and the provisional feedback braking force FBbrakeForce is smaller than the feedback braking force FBbrakeForce (previous value), the feedback braking force FBbrakeForce (previous value) is set to the upper limit value. Yes.

  Thereafter, the process proceeds to step 180m to determine whether or not the vehicle has suddenly decelerated. For example, it is determined whether or not the vehicle has suddenly decelerated by determining whether or not the vehicle body acceleration DV0 has become less than a drop determination threshold value KDV1 (eg, 0.2 G) corresponding to a predetermined deceleration. . If an affirmative determination is made here, the routine proceeds to step 180n, and as the control of (6) described above, a predetermined adaptation constant K4 is added to the value obtained by adding the predetermined braking force α1 to the required braking force BrakeSlopeForce and the driving force DriveForce. The largest value among the three correction values α2 that are the multiplied correction value and the output lower limit value of the feedback braking force FBbrakeForce is set as the correction value T1, and this is set as the feedback braking force FBbrakeForce. However, since the vehicle is decelerating rapidly and the current feedback braking force FBbrakeForce is smaller than the feedback braking force FBbrakeForce (previous value), the feedback braking force FBbrakeForce (previous value) is set to the upper limit value.

  In this way, the controls (1) to (6) are executed, and the processes shown in FIG. 5 are completed. Thereafter, the process proceeds to step 185 in FIG. 4B, and normal control gain setting is performed. That is, the feedback gain BrakeGain for executing the brake control by the feedback control is set, for example, the gains of the P term, the I term, and the D term in the PID control are set. The gain at this time is set to a normal gain that is generally performed as brake control.

  In step 190, the final feedback braking force FBbrakeForce is calculated. Specifically, using the feedback braking force FBbrakeForce calculated in step 180, the feedback gain BrakeGain and braking force conversion set in step 185 to the deviation between the vehicle body speed V0 and the target speed TBV with respect to this feedback braking force FBbrakeForce The final feedback braking force, FBbrakeForce, is calculated by adding the value multiplied by the factor.

  In step 195, the feedback braking force FBbrakeForce calculated in step 190 is converted into each wheel braking force. Here, each wheel braking force BrakeForce ** is calculated by multiplying the feedback braking force FBbrakeForce by each wheel braking force gain EachBrakeGain ** that determines the distribution of each wheel FL to RR. Each wheel braking force gain EachBrakeGain ** is usually ¼ so as to be uniform among the four wheels FL to RR, but the distribution of the front wheels FR and FL is larger than that of the rear wheels RR and RL. The distribution may be changed between the front and rear wheels. Then, the process proceeds to step 200, and the target pressure TargetPress ** of the W / C pressure of each wheel FL to RR is calculated by multiplying each wheel braking force BrakeForce ** calculated in step 195 by the hydraulic pressure converted value. .

  After this, as a control taking TRC into account, it is determined in step 205 whether or not the TRC is being controlled. If the control is in progress, the process proceeds to step 210 and is requested by the TRC as a TRC required hydraulic pressure calculation. Calculate TRC required hydraulic pressure TrcTargetPress **. Then, the process proceeds to step 215 to add the TRC required hydraulic pressure TrcTargetPress ** to the target pressure TargetPress ** of the W / C pressure of each wheel FL to RR obtained in step 200, and finally the crawl control and TRC are added. The target pressure TargetPress ** of the W / C pressure of each of the wheels FL to RR is calculated. Whether or not the TRC is being controlled and the TRC required hydraulic pressure TrcTargetPress ** can be acquired from the ECU executing the TRC (either the brake ECU 19 or the engine ECU 10).

  As described above, when the final target pressure TargetPress ** of the W / C pressure of each wheel FL to RR in consideration of crawl control and TRC is calculated, the target pressure TargetPress ** can be generated. Then, the brake actuator 15 is controlled, and the W / C pressures of W / C 16FL to 16RR are controlled.

  FIGS. 6 and 7 and FIGS. 8 and 9 are time charts showing differences between the conventional feedback control and the feedback control described in the present embodiment, respectively.

  As shown in FIG. 6, in the conventional feedback control, when the vehicle body speed V0 exceeds the target speed TBV, the feedback braking force is set based on the deviation. The feedback braking force is set to a larger value as the deviation increases, and the vehicle body speed V0 is controlled to approach the target speed TBV. However, since the feedback braking force is set simply based on the deviation between the vehicle speed V0 and the target speed TBV, high responsiveness is not obtained, and the difference between the vehicle speed V0 and the target speed TBV is large. It was.

  On the other hand, in the feedback control of the present embodiment, the feedback braking force FBbrakeForce is corrected in a feedforward manner by the above-described controls (1) to (6). For example, the feedback braking force FBbrakeForce is set in consideration of the target deceleration force TBDV and the required slope braking force BrakeSlopeForce. For this reason, as shown in FIG. 7, the vehicle body speed V0 can be made to follow the target speed TBV, and the difference between the vehicle body speed V0 and the target speed TBV can be reduced. Therefore, according to this embodiment, it becomes possible to obtain high responsiveness, and when performing control to keep the vehicle body speed low by controlling the braking force of each wheel FL to RR like crawl control, It is possible to alleviate the driver's uncomfortable feeling.

  Further, an example in which the response on the increase side of the braking force is low will be described with reference to the time charts of FIGS. 8 and 9 correspond to a state where the parking brake is released and the vehicle is going down the slope from a state where the parking brake is stopped on the downhill, for example.

  As shown in FIG. 8, in the conventional feedback control, even when the vehicle speed V0 exceeds the target speed TBV at T1, the speed deviation between the vehicle speed V0 and the target speed TBV is small immediately after T1, and the target braking force is small. As a result, the increase in braking force is slow and the increase in braking force is delayed. Therefore, a sufficient braking force cannot be obtained, and the vehicle body speed V0 increases greatly. Thereafter, the vehicle body speed V0 greatly increases, so that the speed deviation increases and the target braking force is set to be large (T2), so that the braking force also increases suddenly. Then, this time, the braking force becomes excessive, and the vehicle body speed V0 rapidly decreases and falls below the target vehicle body speed TBV (T3). Since the target speed TBV falls below the target speed TBV due to a rapid speed change, the target braking force is set to be smaller than necessary, and the braking force is also rapidly decreased. As a result, the braking force becomes insufficient, and the vehicle speed V0 again exceeds the target speed TBV at T4. Thereafter, similarly, speed hunting occurs in which the vehicle body speed V0 is repeatedly increased and decreased.

  On the other hand, as shown in FIG. 9, in the invention of this embodiment, when the vehicle body speed V0 exceeds the target speed TBV at T1a, the control (1), (2), (3), or a combination is immediately performed. Since the target braking force is set high, the braking force increases at a fast ascending speed, and an excessive increase in the vehicle body speed V0 is suppressed. Next, at T2a, when the increase in the vehicle speed V0 stops, that is, when the vehicle acceleration DV0 changes from positive to 0 (zero) or less, it can be determined that the braking force has increased sufficiently. Therefore, the control (5) is performed to achieve the target braking force. Is updated to an appropriate value. Thereby, it is possible to prevent the braking force from becoming excessive while maintaining a high target braking force. Furthermore, when the vehicle body acceleration DV0 indicates a sudden deceleration such that the vehicle body acceleration DV0 is smaller than KDV1, it can be determined that the current target braking force is still large. Therefore, the control (6) is performed to further reduce the target braking force. It is corrected as follows. As described above, even when the response of the increase in braking force is low, more appropriate control can be performed to prevent speed hunting and the like.

(Other embodiments)
The present invention is not limited to the embodiment described above, and can be appropriately changed within the scope described in the claims.

  For example, in the above embodiment, the crawl control is given as an example of the control for keeping the vehicle body speed at a low speed by controlling the braking force of each of the wheels FL to RR. However, this is merely an example, and the same can be said for other controls such as downhill assist control (DAC). The downhill assist control is similar to the crawl control, and all the crawl control portions described in the first embodiment may be replaced with the downhill assist control.

  In addition, including the steps shown in the drawings, the portion in the brake ECU 19 that executes various processes corresponds to the means for executing the various processes. For example, the part that executes the process of step 180a is the overspeed state determining means, the part that executes the processes of steps 180c, 180d, 180g to 180i, 180k, and 180n is the correcting means, and the part that executes the process of step 180j is accelerated. The determination means, the part that executes the processing of step 180m corresponds to the rapid deceleration determination means. Further, the part that executes the process of step 100 is an acceleration acquisition means or a driving force acquisition means, the part that executes the process of step 140 is an inclination acquisition means, the part that executes the process of step 160 is a target deceleration force calculation means, and step 190 The part that executes the process corresponds to feedback control means.

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Transmission, 2a ... Transmission, 2b ... Sub transmission, 3 ... Driving force distribution control actuator, 10 ... Engine ECU, 11 ... Accelerator pedal, 11a ... Accelerator switch, 12 ... LAN, 13 ... Brake pedal , 14 ... M / C, 15 ... Brake actuator, 16 ... W / C, 19 ... Brake ECU, 20FL-20RR ... Wheel speed sensor, 21 ... Brake switch, 21 ... Brake pedal, 22 ... M / C pressure sensor, 23 ... switch, 23 ... crawl switch, 24 ... target speed setting switch, 25 ... acceleration sensor

Claims (6)

Feedback control means for performing feedback control for calculating a feedback braking force based on a deviation between the vehicle body speed and the target speed for each predetermined control cycle and causing the vehicle body speed to approach the target speed by generating the feedback braking force;
Overspeed state determining means for determining whether or not the vehicle body speed is an overspeed state exceeding the target speed;
When the overspeed state is determined, the feedback braking force rises faster with respect to the deviation between the vehicle body speed and the target speed as compared to a normal running state that is not determined to be the overspeed state. Correction means for correcting the feedback braking force;
Target deceleration force calculating means for calculating a target acceleration / deceleration based on a deviation between the vehicle body speed and the target speed and calculating a target deceleration force that is a braking force necessary to generate the target acceleration / deceleration. And
The correction means calculates the feedback braking force in the current control cycle when it is determined as the overspeed state and the previous value which is the feedback braking force in the previous control cycle is smaller than the target deceleration force. In this case, the feedback braking force is corrected by adding a correction value based on the target deceleration force to the previous value . Feedback control means for performing feedback control for calculating a feedback braking force based on a deviation between the vehicle body speed and the target speed for each predetermined control cycle and causing the vehicle body speed to approach the target speed by generating the feedback braking force;
Overspeed state determining means for determining whether or not the vehicle body speed is an overspeed state exceeding the target speed;
When the overspeed state is determined, the feedback braking force rises faster with respect to the deviation between the vehicle body speed and the target speed as compared to a normal running state that is not determined to be the overspeed state. Correction means for correcting the feedback braking force;
Acceleration acquisition means for acquiring vehicle body acceleration which is acceleration in the longitudinal direction of the vehicle body;
Acceleration determining means for determining whether or not the vehicle is accelerating based on the vehicle body acceleration;
Inclination acquisition means for acquiring the inclination of the traveling road surface of the vehicle,
When the correction means is determined to be in the overspeed state and the vehicle is determined to be accelerating, the braking force required on the hill is a braking force required for the vehicle to stop on the inclined hill. predetermined braking force value obtained by multiplying the adapted constant value obtained by adding toward the larger one of the feedback braking force, drive both brake you and corrects the feedback braking force to. Feedback control means for performing feedback control for calculating a feedback braking force based on a deviation between the vehicle body speed and the target speed for each predetermined control cycle and causing the vehicle body speed to approach the target speed by generating the feedback braking force;
Overspeed state determining means for determining whether or not the vehicle body speed is an overspeed state exceeding the target speed;
When the overspeed state is determined, the feedback braking force rises faster with respect to the deviation between the vehicle body speed and the target speed as compared to a normal running state that is not determined to be the overspeed state. Correction means for correcting the feedback braking force;
Acceleration acquisition means for acquiring vehicle body acceleration which is acceleration in the longitudinal direction of the vehicle body;
Acceleration determining means for determining whether or not the vehicle is accelerating based on the vehicle body acceleration,
The correction means is adapted to a vehicle acceleration force that is a braking force necessary to reduce the vehicle body acceleration to 0 when the vehicle is determined to be in the overspeed state and the vehicle is being accelerated. the larger one a value obtained by multiplying the constant of the feedback braking force, drive both brake you and corrects the feedback braking force. Feedback control means for performing feedback control for calculating a feedback braking force based on a deviation between the vehicle body speed and the target speed for each predetermined control cycle and causing the vehicle body speed to approach the target speed by generating the feedback braking force;
Overspeed state determining means for determining whether or not the vehicle body speed is an overspeed state exceeding the target speed;
When the overspeed state is determined, the feedback braking force rises faster with respect to the deviation between the vehicle body speed and the target speed as compared to a normal running state that is not determined to be the overspeed state. Correction means for correcting the feedback braking force;
Acceleration acquisition means for acquiring vehicle body acceleration which is acceleration in the longitudinal direction of the vehicle body;
Acceleration determining means for determining whether or not the vehicle is accelerating based on the vehicle body acceleration;
Driving force acquisition means for acquiring the driving force of the vehicle,
If the correction means is determined to be in the overspeed state and the vehicle is determined to be accelerating, the value obtained by multiplying the driving force by an adaptation constant or the feedback braking force, whichever is greater the car both brake you and corrects the feedback braking force. Feedback control means for performing feedback control for calculating a feedback braking force based on a deviation between the vehicle body speed and the target speed for each predetermined control cycle and causing the vehicle body speed to approach the target speed by generating the feedback braking force;
Overspeed state determining means for determining whether or not the vehicle body speed is an overspeed state exceeding the target speed;
When the overspeed state is determined, the feedback braking force rises faster with respect to the deviation between the vehicle body speed and the target speed as compared to a normal running state that is not determined to be the overspeed state. Correction means for correcting the feedback braking force;
Acceleration acquisition means for acquiring vehicle body acceleration which is acceleration in the longitudinal direction of the vehicle body;
An acceleration end determination means for determining an acceleration end time when the vehicle is accelerating based on the vehicle body acceleration;
Inclination acquisition means for acquiring the inclination of the traveling road surface of the vehicle,
When the correction means is determined to be in the overspeed state and is determined to be at the end of acceleration of the vehicle, the feedback braking force and the braking force required for the vehicle to stop on the slope with the slope. in a braking force so as to a value obtained by adding a predetermined braking force becomes a predetermined distribution with respect to slope required braking force, drive both brake you and corrects the feedback braking force. Feedback control means for performing feedback control for calculating a feedback braking force based on a deviation between the vehicle body speed and the target speed for each predetermined control cycle and causing the vehicle body speed to approach the target speed by generating the feedback braking force;
Overspeed state determining means for determining whether or not the vehicle body speed is an overspeed state exceeding the target speed;
When the overspeed state is determined, the feedback braking force rises faster with respect to the deviation between the vehicle body speed and the target speed as compared to a normal running state that is not determined to be the overspeed state. Correction means for correcting the feedback braking force;
Acceleration acquisition means for acquiring vehicle body acceleration which is acceleration in the longitudinal direction of the vehicle body;
Sudden deceleration determination means for determining sudden deceleration at which the vehicle body deceleration represented as a negative value of the vehicle body acceleration is less than a predetermined deceleration;
Driving force acquisition means for acquiring the driving force of the vehicle;
Inclination acquisition means for acquiring the inclination of the traveling road surface of the vehicle,
When the correction means is determined to be in the overspeed state and is determined to be in the sudden deceleration, the vehicle is adjusted to a slope required braking force that is a braking force required for the vehicle to stop on the slope with the slope. The feedback braking force is corrected to the largest value among a value obtained by adding a predetermined braking force, a value obtained by multiplying the driving force by a matching constant, and an output lower limit value of the feedback braking force. car both braking device shall be the feature.

Images