JP6641646B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a control device for a vehicle, and more particularly, to a cooperative control for cooperatively controlling a hydraulic braking force generating means and a regenerative braking force generating means so that a braking force of a vehicle does not exceed a braking operation characteristic of an anti-skid control means. The present invention relates to a vehicle control device provided with control means.

2. Description of the Related Art Conventionally, there has been known a hybrid vehicle that travels by using a motor generator (hereinafter, abbreviated as a motor) that generates a driving force by electric power of a battery and an engine.
In this hybrid vehicle, when the motor is not running (during deceleration, etc.), the motor is operated as a generator, and the rotation (kinetic) energy of the wheels is converted into electric energy and stored in a battery to regenerate the energy. We are aiming for efficient use.

Since the regenerative braking force generating means for regenerating uses the magnetic field generated by the field current in the motor to generate power, the regenerative braking force acting on the drive wheels can be adjusted by controlling the induced voltage. It is possible (for example, Patent Document 1).
Therefore, a technique has been proposed in which the total braking force applied to the vehicle, that is, the hydraulic braking force by the so-called hydraulic braking force generating means and the regenerative braking force by the regenerative braking force generating means are coordinated.

  The vehicle control device of Patent Document 2 can apply a hydraulic braking force generating means capable of applying a hydraulic braking force by a brake hydraulic pressure to a wheel driven by a motor, and can apply a regenerative braking force to a wheel by a rotational load of the motor. At least one of the regenerative braking force generating means and the first condition that the power supply (battery) temperature is equal to or higher than the first threshold and the second condition that the power holding power is equal to or higher than the second threshold are determined by the regenerative braking force. Prediction means for predicting whether or not the condition is satisfied during deceleration.When the prediction means predicts that any of the conditions is satisfied, a hydraulic braking force is used in addition to or instead of the regenerative braking force. It is given to wheels.

Meanwhile, an anti-skid control device (hereinafter, abbreviated as ABS) for preventing a brake lock on each wheel of a vehicle is known.
In general, an ABS presets a wheel slip rate (for example, 20%) at which a wheel can exhibit a high braking force (for example, a maximum braking force) as a target slip rate, and the wheel slip rate is set to a predetermined ABS during vehicle braking. When the operation start threshold value is exceeded, the brake fluid pressure in the wheel cylinders of the wheels is switched to a reduced pressure state, and the wheel slip rate of the traveling vehicle converges to a target slip rate corresponding to a predetermined target state.
This makes it possible to avoid a state where the wheels are continuously locked even during sudden braking, thereby improving steering performance.

JP-A-2006-142118 JP 2017-028914 A

When the occupant operates the brake pedal, the correlation between the operation amount of the brake pedal and the deceleration of the vehicle (total braking force applied to the vehicle) is determined by the occupant on the basis of a predetermined operation characteristic (control map). A braking force is set, and the braking force generating means is controlled by a target operation amount corresponding to the required braking force, thereby controlling the behavior of the vehicle.
Therefore, the shorter the required time from when the occupant operates the brake pedal to when the braking force acting on the vehicle reaches the required braking force, the shorter the braking distance of the vehicle and the higher the braking performance.
However, when the ABS is mounted on the vehicle for the purpose of improving the steering performance, the braking performance of the vehicle cannot be improved more than expected.

In other words, during vehicle braking, if the wheel slip rate temporarily exceeds the ABS operation start threshold value due to some external factor, the ABS switches the brake fluid pressure to a reduced pressure state so that the wheel slip rate converges to the target slip rate. Although safety in terms of braking performance is ensured, the tendency to increase the brake fluid pressure is delayed and the braking distance increases.
Moreover, in the case of using a hydraulic braking force generating means for controlling the flow rate of the viscous fluid brake fluid by an electromagnetic valve, safety is ensured from the viewpoint of operation responsiveness as compared with electric control, There is a concern that the braking distance will further increase.

Therefore, the tendency of the hydraulic braking force to increase (increase speed) so that the hydraulic braking force generated in the vehicle does not exceed the braking force characteristic (hereinafter, referred to as the braking operation characteristic) set to correspond to the ABS operation start threshold value. Is set significantly lower than the braking operation characteristic of the ABS, it is possible to avoid the operation of the ABS that is unwilling for the occupant.
As a result, although the undesired operation of the ABS can be avoided, the time required for the hydraulic braking force to reach the required braking force is further extended, and there is a concern that the braking distance may still be increased while ensuring safety. You.

Further, since the regenerative braking force generating means can perform highly responsive control, it is conceivable to use both the hydraulic braking force and the regenerative braking force as in the vehicle control device of Patent Document 2.
However, in the regenerative braking force generating means, since the operation period and the operation timing are limited by the characteristic of the battery that accumulates the generated electric power, it is difficult to guarantee a stable braking force. It is difficult to always use the regenerative braking force together with the regenerative braking force.
That is, it is desired to establish an effective technique for improving the braking performance of a vehicle equipped with ABS.

  An object of the present invention is to provide a vehicle control device or the like that can achieve both steering performance and braking performance.

A vehicle control device according to claim 1, wherein a hydraulic braking force generating means capable of applying a hydraulic braking force to the wheels by a brake hydraulic pressure, and a regenerative braking system capable of applying a regenerative braking force to the wheels by a rotational load of an electric motor. Power generation means, anti-skid control means for controlling the wheel slip rate to converge to a predetermined target state by a braking force applied to the wheels during vehicle braking, and a request from the occupant based on an operation of depressing a brake pedal by the occupant; The hydraulic pressure is set so as not to exceed a braking operation characteristic which is a braking force corresponding to a predetermined target state of the anti-skid control means until the braking force acting on the vehicle reaches the required braking force while setting the power. the vehicle control device and a cooperative control unit for cooperative control of regenerative system braking force generating means and the system braking force generating means, issued by the regenerative system braking force generating means By the regenerative power has a detectable charge rate detecting means charging rate of the power storage, battery and the cooperative control means smaller than fully charged the charging rate of the detected battery by said charging rate detecting means When the charging rate is less than the predetermined charging rate, the hydraulic braking force is controlled to be smaller than the braking operation characteristic, and the regenerative braking force is controlled to be equal to or less than a braking force corresponding to a difference between the braking operation characteristic and the hydraulic braking force. The regenerative braking force is increased until the sum of the hydraulic braking force and the regenerative braking force reaches the required braking force, and after the sum of the hydraulic braking force and the regenerative braking force reaches the required braking force, It is characterized in that the regenerative braking force is decreased while the hydraulic braking force is increased .

This vehicle control device includes anti-skid control means for controlling the wheel slip rate to converge to a predetermined target state by a braking force applied to the wheel during vehicle braking, so that it is possible to prevent wheel brake lock. And steering performance can be ensured.
The braking force corresponding to the predetermined target state of the anti-skid control means is set until the braking force acting on the vehicle reaches the required braking force while setting the required braking force of the occupant based on the depression operation of the brake pedal by the occupant. Since the cooperative control means for cooperatively controlling the hydraulic braking force generating means and the regenerative braking force generating means so as not to exceed the braking operation characteristic is provided until the braking force acting on the vehicle reaches the required braking force. During this period, the braking force of the vehicle can be increased without activating the braking force reduction process by the anti-skid control means.
The cooperative control means controls the hydraulic braking force to be smaller than the braking operation characteristic when the charge rate of the battery detected by the charge rate detection means is less than a predetermined charge rate set to be smaller than full charge. In addition, in order to control the regenerative braking force to be equal to or less than the braking force corresponding to the difference between the braking operation characteristic and the hydraulic braking force, the braking force corresponding to the difference between the braking operation characteristic and the hydraulic braking force is compensated by the regenerative braking force having high responsiveness. The braking force acting on the vehicle can reach the required braking force early. Further, the cooperative control means increases the regenerative braking force until the sum of the hydraulic braking force and the regenerative braking force reaches the required braking force, and the sum of the hydraulic braking force and the regenerative braking force becomes the required braking force. After reaching, the hydraulic braking force is increased and the regenerative braking force is decreased, so that the transition from the combined braking period of the hydraulic braking force and the regenerative braking force to the independent braking period by the hydraulic braking force without a switching shock occurs. Can be.

The invention of claim 2 is characterized in that, in the invention of claim 1, the cooperative control means sets the rate of increase of the regenerative braking force to be smaller than the rate of increase of the hydraulic braking force.
According to this configuration, the full charge can be delayed, and the frequency of applying the regenerative braking force for promoting the load movement of the vehicle body weight can be increased.

According to a third aspect of the present invention, in the first or second aspect of the invention, the cooperative control means is configured to execute the regenerative braking force after a predetermined period has elapsed after the sum of the hydraulic braking force and the regenerative braking force has reached the required braking force. Is prohibited.
According to this configuration, the full charge can be further delayed, and the frequency of applying the regenerative braking force for promoting the load transfer of the vehicle body weight can be increased.

According to a fourth aspect of the present invention, in the first or second aspect of the invention, after the sum of the hydraulic braking force and the regenerative braking force reaches the required braking force, the cooperative control means may determine that the hydraulic braking force and the regenerative braking force The regenerative braking force is controlled to be equal to or less than a braking force corresponding to a difference between the required braking force and the hydraulic braking force when the sum of the power reaches the required braking force.
According to this configuration, the regenerative energy can be recovered while securing the braking force required by the occupant.

According to a fifth aspect of the present invention, in the invention of any one of the first to fourth aspects, the cooperative control means controls the regenerative braking force to a braking force corresponding to a difference between the braking operation characteristic and a hydraulic braking force. It is characterized by.
According to this configuration, the maximum regenerative energy can be recovered.

  ADVANTAGE OF THE INVENTION According to the vehicle control apparatus of this invention, in the vehicle equipped with the anti-skid control means, it is possible to achieve both steering performance and braking performance by performing cooperative control of the hydraulic braking force and the regenerative braking force.

FIG. 1 is an overall schematic configuration diagram of a vehicle control device according to a first embodiment. It is a brake hydraulic circuit diagram of a braking mechanism. FIG. 3 is a functional block diagram of a first ECU and a second ECU. FIG. 4 is an explanatory diagram of a first cooperation mode. It is explanatory drawing of a 2nd cooperation mode. It is explanatory drawing of a 3rd cooperation mode. It is a flowchart which shows an ABS control processing procedure. It is a flowchart which shows a cooperative control processing procedure. It is a flowchart which shows a friction braking mode processing procedure. It is a flowchart which shows a 1st cooperation mode processing procedure. It is a flowchart which shows a 2nd cooperation mode processing procedure. It is a flowchart which shows a 3rd cooperation mode processing procedure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The following description is an example in which the present invention is applied to a control device for a hybrid vehicle, and does not limit the present invention, its application, or its use.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the vehicle V according to the present embodiment includes a braking mechanism B capable of controlling a hydraulic braking force related to the stopping performance of the vehicle V, a driving force related to the running performance of the vehicle V, and the stopping performance of the vehicle V. , A power train mechanism P capable of controlling regenerative braking force, a brake pedal 1 as an input device operable by an occupant, and front, rear, left and right wheels 2a to 2d as output devices. During braking, the vehicle V is controlled by an anti-skid control mechanism (hereinafter referred to as ABS) so that the wheel slip ratio s converges to a predetermined target state. The first to third cooperative modes in which the cooperative braking is performed by the hydraulic braking force and the regenerative braking force can be selectively executed.

First, the braking mechanism B will be described.
FIG. 2 is a brake hydraulic circuit diagram of the braking mechanism B.
As shown in FIGS. 1 and 2, the braking mechanism B includes a stroke simulator 3 (reaction generating mechanism) that applies a reaction force to the brake pedal 1 according to a pedal stroke (hereinafter, abbreviated as a stroke) St. An electric brake booster (hereinafter abbreviated as an electric booster) 4 capable of generating a brake hydraulic pressure corresponding to the hydraulic braking force, and a master capable of directly generating a brake hydraulic pressure corresponding to a stroke St of the brake pedal 1 by an occupant. A cylinder 5 and wheel cylinders 6a to 6d capable of braking the rotation of the four front and rear left and right wheels 2a to 2d of the vehicle V by applying a frictional force by the brake fluid pressure generated by the master cylinder 5 or the electric booster 4. And a first ECU (Electronic Control Unit) 10 or the like capable of controlling the electric booster 4 as a main component.

Next, the stroke simulator 3 will be described.
The stroke simulator 3 simulates the oil consumption and absorbs and consumes the brake fluid pressure fed from the master cylinder. When the occupant depresses or depresses the brake pedal 1, the stroke simulator 3 operates via the brake pedal 1. An operation reaction force having a preset characteristic can be applied to an occupant (an occupant's leg).
The stroke simulator 3 is formed by, for example, a cylinder, a piston slidable in the cylinder, and an urging means for urging the piston (both are not shown). The operation reaction force (pedal force) applied to the occupant is adjusted based on the accompanying brake fluid pressure.

As shown in FIG. 2, the electric booster 4 is connected to the reservoir tank 7, and includes an electric motor, a hydraulic pump, an accumulator (not shown), and the like.
The electric booster 4 is connected to a wheel cylinder 6a, 6b capable of braking the front wheels 2a, 2b, which are driving wheels, via an openable / closable electromagnetic valve 8b, and is a driven wheel via an openable / closable electromagnetic valve 8c. The wheels 2c and 2d are connected to wheel cylinders 6c and 6d that can brake the wheels. The solenoid valves 8b and 8c are opened when energized.
As shown in FIG. 2, return flow paths connected to the reservoir tank 7 are connected to the upstream flow paths of the wheel cylinders 6a to 6d, respectively. Solenoid valves 9a to 9d that are opened by energization are provided in these return passages, respectively.

Next, the master cylinder 5 will be described.
The master cylinder 5 has a first pressure generation chamber 5a and a second pressure generation chamber 5b.
The first and second pressure generating chambers 5a and 5b are respectively connected to the reservoir tank 7 and each have a compression spring therein. These first and second pressure generating chambers 5a and 5b are configured to be able to pump substantially the same brake fluid pressure in accordance with the depression operation of the brake pedal 1.
The first pressure generating chamber 5a communicates with the wheel cylinders 6a and 6b via an openable electromagnetic valve 8a, and the second pressure generating chamber 5b communicates with the wheel cylinders 6c and 6d via an openable electromagnetic valve 8d. Have been. The solenoid valves 8a and 8d are closed when energized, and are de-energized and opened when the electric booster 4 is abnormal.

With the above configuration, when the electric booster 4 is abnormal, the solenoid valves 8a and 8d are opened and the solenoid valves 8b and 8c are closed, and the brake hydraulic pressure is directly applied to the wheel cylinders 6a to 6d from the master cylinder 5. Is supplied. When the electric booster 4 is normal, the solenoid valves 8a and 8d are closed and the solenoid valves 8b and 8c are opened, and the brake fluid pressure is supplied from the electric booster 4 to each of the wheel cylinders 6a to 6d. When the electric booster 4 is normal, the solenoid valves 8b and 8c are closed and the solenoid valves 9a to 9d are opened, whereby the brake fluid pressure is discharged from the wheel cylinders 6a to 6d and is forcibly controlled. Power can be reduced.
The solenoid valves 8b and 8c correspond to ABS inlet valves, and the solenoid valves 9a to 9d correspond to ABS outlet valves.

Next, the first ECU 10 will be described.
The first ECU 10 includes a CPU (Central Processing Unit), a ROM, a RAM, an in-side interface, an out-side interface, and the like, and receives a detection signal from a stroke sensor 21 that detects a stroke St of the brake pedal 1. I have. The ROM stores various programs, data, maps, and the like for controlling the pedaling force and the braking force, and the RAM includes a processing area used when the CPU performs a series of processes.
As shown in FIG. 3, the first ECU 10 includes an operation reaction force setting unit 11, a required braking force setting unit 12, a hydraulic pressure control unit 13, and the like.

The operation reaction force setting unit 11 has a pedaling force characteristic map (not shown) defined by the pedaling force by which the occupant operates the brake pedal 1 and the stroke St of the brake pedal 1.
Since the strength of the occupant's sensation is proportional to the logarithm of the stimulus strength (Weber-Fechner's law), the pedal force characteristic map is defined by a logarithmic function.
The operation reaction force setting unit 11 sets a pedal force corresponding to the target operation reaction force based on the stroke St detected by the stroke sensor 21 and the pedal force characteristic map, and outputs an operation command signal corresponding to the target operation reaction signal to the control brake fluid pressure. The data is output to the stroke simulator 3 via the external device.

The required braking force setting unit 12 has a braking characteristic map (not shown) defined by the pedaling force of the occupant operating the brake pedal 1 and the deceleration (braking force) required by the occupant.
The stroke St reflects the occupant's deceleration request using the occupant's operation amount as a parameter.
Therefore, the required braking force setting unit 12 sets the required braking force Fa required by the occupant to the vehicle V using the pedaling force set via the detected stroke St of the brake pedal 1 and the braking characteristic map. are doing.

The hydraulic pressure control unit 13 creates an operation command signal corresponding to the hydraulic braking force Ff based on the hydraulic braking force Ff in each braking mode input from the second ECU 40 described later, and outputs the operation command signal to the electric booster 4. Specifically, when the friction braking mode and the first to third cooperative modes are executed, the operation command signals for the solenoid valves 8b and 8c are created based on the operation command signals input from the second ECU 40, and the respective wheel cylinders 6a to 6d are operated. Controls brake fluid pressure.
Further, the hydraulic pressure control unit 13 transmits an operation command signal for the solenoid valves 8b and 8c and the solenoid valves 9a to 9d based on the wheel slip rate s in order to converge the wheel slip rate s to a predetermined target state during the ABS operation. It is created and output to each of the solenoid valves 8b, 8c, 9a to 9d.

Next, the power train mechanism P will be described.
As shown in FIG. 1, a power train mechanism P includes a motor generator (hereinafter abbreviated as a motor) 31 as a regenerative braking force (regenerative torque) generation source and power source, and a power transmission mechanism such as a pulley attached to the motor 31. And an automatic transmission (hereinafter abbreviated as AT) as a fluid transmission mechanism capable of transmitting a driving force to front wheels 2a and 2b via a differential mechanism. 33, a second ECU 40 that can control the motor 31, the engine 32, and the like.

The motor 31 is composed of a three-phase AC synchronous motor connected to the wheels 2a and 2b and has a switching mechanism (not shown) having a switching function capable of linearly switching the energization state of each winding. Is configured to be able to control the induced voltage generated at the same time.
Therefore, when the vehicle V decelerates, a reverse torque based on the induced voltage in the motor 31 is applied to the wheels 2a, 2b, and the electric power generated by the motor 31 is supplied to the second battery 36 (for example, lithium ion Battery, etc.).

The second ECU 40 includes a CPU, a ROM, a RAM, an in-side interface, an out-side interface, and the like. The ROM stores various programs, data, maps, and the like for controlling the amount of regeneration, and the RAM includes a processing area used when the CPU performs a series of processes.
The second ECU 40 is mainly in parallel with the electric booster 4, the first ECU 10, the DCDC converter 34 for converting the power supply voltage generated by the motor 31, and various loads (not shown) such as an air conditioner mounted on the vehicle V. It is electrically connected to a first battery 35 as a power supply.
The DCDC converter 34 is configured to be able to supply the converted power supply voltage to the first battery 35.

  Further, the second ECU 40 includes an SOC sensor 22 that can detect a state of charge (SOC) of the second battery 36, a temperature sensor 23 that can detect the temperature of the second battery 36, and a vehicle speed (vehicle speed) of the vehicle V. ), A wheel speed sensor 25 capable of detecting the speeds of the wheels 2a to 2d, a rod displacement sensor 26 capable of detecting the displacement of the suspension rod length of the wheels 2a to 2d, and a vehicle V Each detection signal is input from a gradient sensor 27 capable of detecting the gradient of the road surface on which the vehicle travels, and an operation command signal is output to the first ECU 10 and the motor 31.

  As shown in FIG. 3, the second ECU 40 controls the wheel slip rate s to converge to a predetermined target state by a braking force applied to the wheels 2a to 2d during vehicle braking (anti-skid control means). A load movement detecting unit 42 (load movement detecting means) for detecting a load movement of the body weight of the vehicle V, a cooperative control unit 43 (cooperative control means) for cooperatively controlling the hydraulic braking force Ff and the regenerative braking force Fr, A regenerative controller 44 and the like are provided.

First, the ABS control unit 41 will be described.
When the wheel slip ratio s is larger than the ABS operation start threshold value sa set based on the target state in which the running stability of the vehicle V can be ensured, the ABS control unit 41 closes the electromagnetic valves 8b and 8c and performs the electromagnetic valve closing. It is configured to open the 9a to 9d to start the ABS control.
During the ABS control, when the wheel slip rate s is larger than the target slip rate sb (sb <sa), the solenoid valves 8b and 8c are closed and the solenoid valves 9a to 9d are opened, and the wheel cylinders 6a to 6d are opened. While the wheel slip rate s is equal to or less than the target slip rate sb, the solenoid valves 8b and 8c are opened and the solenoid valves 9a to 9d are closed. By increasing the hydraulic pressure of the wheel cylinders 6a to 6d, the braking force of the wheels 2a to 2d is increased.

The ABS control unit 41 calculates the wheel slip ratio s of the front wheels 2a and 2b based on the detection signals of the vehicle speed sensor 24 and the wheel speed sensor 25. Specifically, a pseudo slip ratio obtained by dividing the difference between the wheel speed of the front wheels 2a and the vehicle speed by the vehicle speed and a pseudo slip ratio obtained by dividing the difference between the wheel speed of the front wheels 2b and the vehicle speed by the vehicle speed are calculated. Of these pseudo slip rates, the larger value of the pseudo slip rate is set as the wheel slip rate s representing the front wheels 2a and 2b. As the vehicle speed, the slower one of the wheel speeds of the rear wheels 2c and 2d, which are the driven wheels, is used as the vehicle speed.
The ABS operation start threshold value sa and the target slip ratio sb are respectively calculated based on the road surface μ. In this embodiment, the road surface μ is estimated and calculated by comparing the detected wheel speed and the acceleration of the vehicle V with the μ table. However, a μ sensor may be provided, and the output value from this μ sensor may be used. .

As shown in FIG. 3, the ABS control unit 41 has a braking operation characteristic setting unit 41a.
The braking operation characteristic setting unit 41a sets a braking operation characteristic A that defines a braking force tendency of the vehicle V corresponding to the ABS operation start threshold value sa.
As shown in FIGS. 4 to 6, the braking operation characteristic A is defined by the time t from the start of braking and the braking force acting on the vehicle V.
The braking operation characteristic A can be expressed by a linear function of the following equation when the road surface μ is constant.
A = K1 × t (1)
Note that K1 is an ABS operation coefficient.
Therefore, when the occupant depresses the brake pedal 1, even if the braking force of the vehicle V does not reach the required braking force Fa (attainment time tb), the vehicle V is temporarily moved with the decrease of the road surface μ. When the applied braking force exceeds the braking operation characteristic A, the pressure reduction processing by the ABS is executed, and the brake fluid pressure of the wheel cylinders 6a to 6d is reduced.

Next, the load movement detection unit 42 will be described.
The load movement detection unit 42 detects the displacement speed and the displacement acceleration of the suspension rods of the wheels 2a to 2d based on the displacement of the suspension rod lengths of the wheels 2a to 2d input from the rod displacement sensors 26, respectively.
Based on the detected displacement speeds and displacements of the suspension rods of the wheels 2a to 2d, the load movement of the vehicle body weight of the vehicle V is detected.

Next, the cooperative control unit 43 will be described.
The cooperative control unit 43 selects a corresponding braking mode from the friction braking mode and each of the cooperative modes in accordance with the state of charge SOC of the second battery 36 detected by the SOC sensor 22 during vehicle braking, and sets a predetermined cooperative mode. Is selected, the hydraulic braking force Ff by the braking mechanism B and the regenerative braking force Fr by the power train mechanism P are cooperatively controlled.
Specifically, when the SOC is 97% or more, the friction braking mode, when the SOC is 90% or more and less than 97%, the first cooperative mode, when the SOC is 30% or more and less than 90%, the second When the cooperative mode and the SOC are less than 30%, the third cooperative mode is selected.

The cooperative control unit 43 sets an operation characteristic corresponding to the speed at which the hydraulic braking force Ff is increased by the braking mechanism B based on the braking operation characteristic A. The operation characteristic of the hydraulic braking force Ff is defined by the time t from the start of braking and the braking operation characteristic A.
The operation characteristic of the hydraulic braking force Ff can be expressed by a linear function of the following equation.
Ff = K2 × t (2)
K2 is a friction braking operation coefficient.
The operation characteristic of the hydraulic braking force Ff is set to a value smaller than the braking operation characteristic A so that the ABS does not operate due to a temporary fluctuation of the braking force on the vehicle V (a fluctuation of the road surface μ).
In the present embodiment, the friction braking operation coefficient K2 is set within a range defined by the following equation in consideration of the braking distance of the vehicle V.
1/2 × K1 ≦ K2 <2/3 × K1 (3)

  As shown in FIG. 3, the cooperative control unit 43 includes a first cooperative mode control unit 43a and a second cooperative mode control in which the ratio of the regenerative braking force Fr to the total braking force is larger than that of the first cooperative mode control unit 43a. And a third cooperative mode control unit 43c in which the ratio of the regenerative braking force Fr to the total braking force is larger than that of the second cooperative mode control unit 43b during the period when the maximum load moves to the front wheels 2a and 2b. .

First, the first cooperative mode control unit 43a will be described.
As shown in FIG. 4, during the regenerative operation period from the start of braking to the time ta, the first cooperative mode control unit 43a executes the independent braking by the regenerative braking force Fr in which the application of the hydraulic braking force Ff is prohibited, and at the time ta Thereafter, independent braking is performed by the hydraulic braking force Ff in which application of the regenerative braking force Fr is prohibited. Specifically, the regenerative braking force Fr is controlled to increase by the operation characteristic of Expression (4) having the same coefficient as the braking operation characteristic A until time ta, and after the time ta, the hydraulic braking force Ff is increased by the operation characteristic of Expression (2). Is controlled to increase.
Fr = K1 × t (4)
As a result, even when the SOC of the second battery 36 is close to the full charge, the frequency of applying the regenerative braking force Fr that promotes the load movement of the vehicle body weight is increased.

The first cooperative mode control unit 43a calculates the time ta based on the SOC and the internal resistance of the second battery 36.
Since time ta is set in proportion to the reciprocal of the SOC of second battery 36, the higher the SOC, the shorter the regenerative operation period.
Also, since the time ta is set in proportion to the reciprocal of the internal resistance of the second battery 36, the lower the temperature of the second battery 36 is, the lower the regeneration of the second battery 36 except for the period of normal temperature (−20 ° C. to 20 ° C.). The operation period is shortened, and the higher the temperature of the second battery 36, the shorter the regeneration operation period.
The first cooperative mode control unit 43a determines that the sum of the hydraulic braking force Ff and the regenerative braking force Fr (basically, the regenerative operation period is a short period, so the hydraulic braking force Ff) has reached the required braking force Fa. At the time point (time tb), the braking force increase control ends, and the required braking force Fa is maintained until the occupant depresses the brake pedal 1.

Next, the second cooperative mode control unit 43b will be described.
As shown in FIG. 5, the second cooperative mode control unit 43b controls the hydraulic braking force Ff so as to be smaller than the braking operation characteristic A and also sets the regenerative braking force Fr to the difference between the braking operation characteristic A and the hydraulic braking force Ff. It is controlled to be below the considerable braking force.
The second cooperative mode control unit 43b prohibits the application of the regenerative braking force Fr after a predetermined period has elapsed after the sum of the hydraulic braking force Ff and the regenerative braking force Fr has reached the required braking force Fa.

Specifically, the hydraulic braking force Ff is controlled to increase with the operating characteristic of the equation (2) until the time tb at which the operating characteristic of the hydraulic braking force Ff corresponds to the required braking force Fa. The required braking force Fa is maintained until the driver steps back on the step S1.
Further, the regenerative braking force Fr is controlled to increase by the operation characteristic of Expression (5) until the time tc at which the braking operation characteristic A corresponds to the required braking force Fa, and from the time tc to the time tb, the operation characteristic of Expression (6) is obtained. Is controlled to decrease.
Fr = (K1−K2) × t (5)
Fr = Fa−K2 × t (6)

As a result, the braking force corresponding to the difference between the braking operation characteristic A and the hydraulic braking force Ff can be compensated for by using the regenerative braking force Fr having high responsiveness, and the braking force acting on the vehicle V can be quickly reduced to the required braking force Fa. Has been reached. In addition, after the braking force acting on the vehicle V reaches the required braking force Fa, the braking force acting on the vehicle V is accurately determined using the regenerative braking force Fr until the hydraulic braking force Ff reaches the required braking force Fa. The required braking force Fa is converged.
After the hydraulic braking force Ff reaches the required braking force Fa, the application of the regenerative braking force Fr is prohibited.

Next, the third cooperation mode control unit 43c will be described.
As shown in FIG. 6, the third coordination mode control unit 43c controls the regenerative braking force Fr to be larger than the hydraulic braking force Ff during a set period from the start of braking.
The third cooperative mode control unit 43c sets a set period from the start of braking to the maximum load movement of the vehicle weight on the front wheels 2a and 2b based on the detection result of the load movement detection unit 42.

Specifically, based on the displacement speed and displacement acceleration of the suspension rods of the wheels 2a to 2d input from the load movement detection unit 42, the time td at which the maximum weight of the vehicle weight moves on the front wheels 2a and 2b is detected, and the time from the start of braking is detected. A set period up to td is set.
Moreover, when the road surface ahead in the traveling direction of the vehicle V has a large downward descent toward the downward direction, the time td is changed to an earlier time so that the set period becomes shorter in accordance with the road surface gradient detected by the gradient sensor 27. I have.
Accordingly, the switching timing based on the load movement can be optimized according to the gradient of the road surface on which the vehicle V runs.

Then, from the start of braking to the time td, the third cooperative mode control unit 43c prohibits the application of the hydraulic braking force Ff and sets the regenerative braking force Fr to the operating characteristic of Expression (4) having the same coefficient as the braking operating characteristic A. After the time td, the application of the regenerative braking force Fr is prohibited, and the hydraulic braking force Ff is controlled to increase by the operation characteristic of the equation (2).
Thus, by increasing the use ratio of the regenerative braking force Fr immediately after braking, the maximum load transfer to the front wheels 2a and 2b capable of exhibiting a high braking force is accelerated, and the braking force acting on the vehicle V is reduced. The required braking force Fa is reached early.

  The regenerative control unit 44 creates an operation command signal corresponding to the regenerative braking force Fr input from the cooperative control unit 43, and outputs the signal to the switching mechanism of the motor 31. Specifically, when executing the first to third cooperative modes, an operation command signal for the switching mechanism of the motor 31 is created based on the regenerative braking force Fr input from the cooperative control unit 43, and the induced voltage generated in the motor 31 is determined. Controlling.

Next, the ABS control processing procedure will be described based on the flowchart of FIG.
Note that Si (i = 1, 2,...) Indicates steps for each process.

As shown in FIG. 7, first, various information is read (S1), and the process proceeds to S2.
In S2, it is determined whether or not the brake pedal 1 has been depressed by the occupant.
As a result of the determination in S2, when the brake pedal 1 is depressed by the occupant, the wheel slip ratio s of the front wheels 2a and 2b is calculated based on the detection signals of the vehicle speed sensor 24 and the wheel speed sensor 25 (S3), and the process proceeds to S4. Transition.
In S4, the road surface μ is calculated based on the wheel speed and the acceleration of the vehicle V, and the process proceeds to S5.
In S5, the ABS operation start threshold value sa and the target slip ratio sb are calculated based on the road surface μ, and the process proceeds to S6.

In S6, it is determined whether or not the flag F is 0.
As a result of the determination in S6, if the flag F is 0, that is, if so-called ABS control has not been executed, the process proceeds to S7.
In S7, it is determined whether or not the wheel slip ratio s is equal to or greater than the ABS operation start threshold value sa.
If the result of determination in S7 is that the wheel slip ratio s is equal to or greater than the ABS operation start threshold value sa, 1 is substituted for the flag F (S8), and the process proceeds to S9.
In S9, the solenoid valves 8b and 8c are closed and the solenoid valves 9a to 9d are opened to execute the decompression process, and then the process returns.
If the result of determination in S6 is that flag F is 1, so-called ABS control has already been executed, the flow proceeds to S10.

In S10, it is determined whether or not the wheel slip rate s is equal to or greater than the target slip rate sb.
As a result of the determination in S10, if the wheel slip rate s is equal to or more than the target slip rate sb, the process proceeds to S9, and if the wheel slip ratio s is less than the target slip ratio sb, the process proceeds to S12.
In S12, the solenoid valves 8b and 8c are opened and the solenoid valves 9a to 9d are closed to execute the pressure increasing process, and then the process returns.
If the result of determination in S2 is that the brake pedal 1 has not been depressed by the occupant, 0 is substituted for the flag F (S11), and the flow proceeds to S12.

Next, the cooperative control processing procedure will be described based on the flowchart of FIG.
The cooperative control process is repeatedly executed at a predetermined cycle, and is executed in parallel with the ABS control process shown in FIG.

As shown in FIG. 8, first, various information is read (S21), and the process proceeds to S22.
In S22, it is determined whether or not the brake pedal 1 has been depressed by the occupant.
If the result of determination in S22 is that the brake pedal 1 has been depressed by the occupant, the flow proceeds to S23.
In S23, it is determined whether the flag f is 0, that is, whether any so-called cooperative mode processing is being executed.
If the result of the determination in S23 is that the flag f is 0, the required braking force Fa required by the occupant is calculated (S24), and the flow proceeds to S25.
In S25, the ABS operation braking characteristic A and the ABS operation coefficient K1 are calculated based on the ABS operation start threshold value sa, and the friction braking coefficient K2 is calculated based on the braking performance of the vehicle V (S26). Then, the process proceeds to S27.

In S27, it is determined whether or not the SOC of the second battery 36 is 97% or more.
As a result of the determination in S27, when the SOC of the second battery 36 is 97% or more, the possibility that the second battery 36 will be overcharged by execution of the regenerative braking is extremely high, and the process proceeds to S28.
In S28, a friction braking mode process is executed, and the process returns.
As a result of the determination in S27, when the SOC of the second battery 36 is less than 97%, the process proceeds to S29, and it is determined whether or not the SOC of the second battery 36 is 90% or more.
If the result of the determination in S29 is that the SOC of the second battery 36 is 90% or more, there is a high possibility that the second battery 36 will be overcharged due to execution of regenerative braking, so the flow proceeds to S30.
In S30, the first cooperative mode processing is executed, 1 is substituted for the flag f (S31), and the process returns.

If the result of the determination in S29 is that the SOC of the second battery 36 is less than 90%, the flow shifts to S32, where it is determined whether or not the SOC of the second battery 36 is 30% or more.
If the result of the determination in S32 is that the SOC of the second battery 36 is 30% or more, it is unlikely that the second battery 36 will be overcharged due to execution of regenerative braking, so the flow proceeds to S33.
In S33, the second coordination mode processing is executed, and the flow shifts to S31.
If the result of the determination in S32 is that the SOC of the second battery 36 is less than 30%, it is extremely unlikely that the second battery 36 will be overcharged due to the execution of regenerative braking, so the flow proceeds to S34.
In S34, a third coordination mode process is executed, and the flow shifts to S31.

Next, the friction braking mode processing in S28 will be described.
As shown in the flowchart of FIG. 9, in the friction braking mode process, first, in S41, the hydraulic braking force Ff is set based on the equation (2) and the elapsed time t from the start of braking, and the regenerative braking force Fr is set to 0. After setting, the process proceeds to S42.
In S42, an operation command signal of the set hydraulic braking force Ff and the regenerative braking force Fr is output, and the process proceeds to S43.
In S43, it is determined whether the hydraulic braking force Ff is equal to or more than the required braking force Fa.
If the result of determination in S43 is that the hydraulic braking force Ff is equal to or greater than the required braking force Fa, the process ends. If the hydraulic braking force Ff is less than the required braking force Fa, the process returns to S41.

Next, the first cooperative mode processing of S30 will be described.
As shown in the flowchart of FIG. 10, in the first cooperative mode processing, first, in S51,
The time ta corresponding to the regenerative operation period is calculated based on the SOC and the internal resistance of the second battery 36, and the process proceeds to S52.

In S52, it is determined whether the elapsed time t from the start of braking is equal to or less than the time ta.
As a result of the determination in S52, when the elapsed time t from the start of the braking is equal to or less than the time ta, the hydraulic braking force Ff is set to 0 and the regenerative braking force Fr is set based on the equation (4) and the elapsed time t from the start of the braking. (S53), and then proceeds to S54.
In S54, an operation command signal for the set hydraulic braking force Ff and the regenerative braking force Fr is output, and the process proceeds to S55.

In S55, it is determined whether or not the sum of the hydraulic braking force Ff and the regenerative braking force Fr has reached the required braking force Fa.
If the result of determination in S55 is that the sum of the hydraulic braking force Ff and the regenerative braking force Fr has reached the required braking force Fa, the process ends.
If the result of the determination in S55 is that the sum of the hydraulic braking force Ff and the regenerative braking force Fr has not reached the required braking force Fa, the process returns to S52.
As a result of the determination in S52, when the elapsed time t from the start of braking exceeds the time ta, the hydraulic braking force Ff is set based on the equation (2) and the elapsed time t from the start of braking, and the regenerative braking force Fr is set to 0. After setting (S56), the process proceeds to S42.

Next, the second cooperative mode processing of S33 will be described.
As shown in the flowchart of FIG. 11, in the second cooperative mode processing, first, in S61, it is determined whether the sum of the hydraulic braking force Ff and the regenerative braking force Fr is less than the required braking force Fa.
As a result of the determination in S61, when the sum of the hydraulic braking force Ff and the regenerative braking force Fr is less than the required braking force Fa, the hydraulic braking force Ff is set based on the equation (2) and the elapsed time t from the start of the braking, and the regenerative braking is performed. The power Fr is set based on the equation (5) and the elapsed time t from the start of braking (S62), and the process proceeds to S63.

In S63, an operation command signal for the set hydraulic braking force Ff and regenerative braking force Fr is output, and the process returns to S61.
As a result of the determination in S61, if the sum of the hydraulic braking force Ff and the regenerative braking force Fr is equal to or greater than the required braking force Fa, it is determined whether the hydraulic braking force Ff set by the operation characteristic of Expression (2) is equal to or greater than the required braking force Fa. A determination is made (S64).

If the result of determination in S64 is that the hydraulic braking force Ff is equal to or greater than the required braking force Fa, the hydraulic braking force Ff is set to the required braking force Fa, the regenerative braking force Fr is set to 0 (S65), and the process proceeds to S66.
In S66, an operation command signal for the set hydraulic braking force Ff and regenerative braking force Fr is output, and the process ends.
If the result of determination in S64 is that the hydraulic braking force Ff is less than the required braking force Fa, the hydraulic braking force Ff is set based on the equation (2) and the elapsed time t from the start of braking, and the regenerative braking force Fr is defined by the equation (6). And based on the elapsed time t from the start of braking (S67), and the routine goes to S63.

Next, the third cooperative mode processing of S34 will be described.
As shown in the flowchart of FIG. 12, in the third cooperative mode process, first, in S71, it is determined whether or not the timing is before the switching timing based on the load movement of the vehicle V.
The switching timing for switching from the regenerative braking to the hydraulic braking is determined based on the time td when the maximum load of the vehicle body weight moves on the front wheels 2a and 2b. At this time, the time td is adjusted so as to be shorter according to the magnitude of the forward descending gradient.
If the result of determination in S71 is that before the switching timing based on the load movement of the vehicle V, the hydraulic braking force Ff is set to 0, and the regenerative braking force Fr is set based on Expression (4) and the elapsed time t from the start of braking. (S72) The process proceeds to S73.

In S73, an operation command signal for the set hydraulic braking force Ff and regenerative braking force Fr is output, and the process returns to S71.
If the result of determination in S71 is that after the switching timing based on the load movement of the vehicle V, it is determined whether or not the hydraulic braking force Ff set by the operation characteristic of Expression (2) is equal to or greater than the required braking force Fa (S74).

If the result of determination in S74 is that the hydraulic braking force Ff is equal to or greater than the required braking force Fa, the hydraulic braking force Ff is set to the required braking force Fa, the regenerative braking force Fr is set to 0 (S75), and the process proceeds to S76.
In S76, an operation command signal for the set hydraulic braking force Ff and regenerative braking force Fr is output, and the process ends.
If the result of determination in S74 is that the hydraulic braking force Ff is less than the required braking force Fa, the hydraulic braking force Ff is set based on the equation (2) and the elapsed time t from the start of braking, and the regenerative braking force Fr is set to 0. (S77), and proceeds to S73.

Next, the operation and effect of the vehicle control device will be described.
The control device according to the first embodiment includes the ABS control unit 41 that controls the wheel slip ratio s to converge to the ABS operation start threshold value sa by the braking force applied to the wheels 2a to 2d during vehicle braking. The brake locks 2a to 2d can be prevented, and steering performance can be ensured.
The required braking force Fa of the occupant is set based on the depressing operation of the brake pedal 1 by the occupant, and the ABS operation start threshold value sa of the ABS control unit 41 is set until the braking force acting on the vehicle V reaches the required braking force Fa. Since the cooperative control unit 43 for cooperatively controlling the braking mechanism B and the power train mechanism P so as not to exceed the braking operation characteristic A corresponding to the braking force is provided, the braking force acting on the vehicle V reaches the required braking force Fa. In the meantime, the braking force of the vehicle V can be increased without activating the braking force reduction process by the ABS control unit 41.
The cooperative control unit 43 controls the hydraulic braking force Ff to be smaller than the braking operation characteristic A and controls the regenerative braking force Fr to be equal to or less than the braking force corresponding to the difference between the braking operation characteristic A and the hydraulic braking force Ff. The braking force corresponding to the difference between the braking operation characteristic A and the hydraulic braking force Ff can be compensated for by the regenerative braking force Fr having high response, and the braking force acting on the vehicle V can reach the required braking force Fa early. it can.

  Since the cooperative control unit 43 sets the rate of increase of the regenerative braking force Fr to be smaller than the rate of increase of the hydraulic braking force Ff, the full charge of the second battery 36 can be delayed, and the weight of the vehicle body can be reduced. The frequency of applying the regenerative braking force Fr that promotes the load movement can be increased.

  The cooperative control unit 43 increases the regenerative braking force Fr until the sum of the hydraulic braking force Ff and the regenerative braking force Fr reaches the required braking force Fa, and the sum of the hydraulic braking force Ff and the regenerative braking force Fr becomes the required braking force. After reaching Fa, the regenerative braking force Fr is reduced, so that it is possible to shift from the combined braking period of the hydraulic braking force Ff and the regenerative braking force Fr to the independent braking period by the hydraulic braking force Ff without causing a switching shock.

  The cooperative control unit 43 further prohibits the application of the regenerative braking force Fr after a predetermined period has elapsed after the sum of the hydraulic braking force Ff and the regenerative braking force Fr has reached the required braking force Fa. Can be delayed, and the frequency of applying the regenerative braking force Fr that promotes the load movement of the vehicle weight can be increased.

  After the sum of the hydraulic braking force Ff and the regenerative braking force Fr reaches the required braking force Fa, the coordination control unit 43 performs a request when the sum of the hydraulic braking force Ff and the regenerative braking force Fr reaches the required braking force Fa. Since the regenerative braking force Fr is controlled to be equal to or less than the braking force corresponding to the difference between the braking force Fa and the hydraulic braking force Ff, the regenerative energy can be recovered while securing the braking force Fa required by the occupant.

  Since the cooperative control unit 43 controls the regenerative braking force Fr to a braking force corresponding to the difference between the braking operation characteristic A and the hydraulic braking force Ff, it is possible to recover the maximum regenerative energy.

Next, a modified example in which the above-described embodiment is partially modified will be described.
1) In the above-described embodiment, an example has been described in which the present invention is applied to a hybrid vehicle in which wheels can be driven by an engine. However, the present invention may be applied to an electric vehicle without an engine.
Also, an example in which the invention is applied to a front wheel drive vehicle has been described, but the invention may be applied to a rear wheel drive vehicle or a four wheel drive vehicle.

2) In the above embodiment, an example was described in which the regenerative braking force was controlled to a braking force corresponding to the difference between the braking operation characteristic and the hydraulic braking force. However, in order to ensure control stability, the regenerative braking force was controlled by the braking operation characteristic. The braking force may be controlled to be reduced by a certain amount from the difference between the braking force and the hydraulic braking force.

3) In addition, those skilled in the art can implement the present invention in a form in which various changes are added to the above-described embodiment or in a form in which each embodiment is combined, without departing from the gist of the present invention. Various modifications are also included.

Reference Signs List 1 brake pedals 2a to 2d wheels 31 motor 41 ABS control unit 43 cooperative control unit B braking mechanism P power train mechanism V vehicle

Claims (5)

A hydraulic braking force generating means capable of applying a hydraulic braking force by a brake hydraulic pressure to a wheel; a regenerative braking force generating means capable of applying a regenerative braking force to the wheel by a rotational load of an electric motor; and Anti-skid control means for controlling the wheel slip ratio to converge to a predetermined target state by a braking force applied to the vehicle, and a system for setting a required braking force of the occupant based on a depressing operation of a brake pedal by the occupant and acting on the vehicle. The hydraulic braking force generating means and the regenerative braking force so that a braking operation characteristic which is a braking force corresponding to a predetermined target state of the anti-skid control means is not exceeded until the power reaches the required braking force. A vehicle control device including a cooperative control unit that cooperatively controls the generating unit,
Having a charging rate detecting means capable of detecting a charging rate of a battery capable of storing regenerative power generated by the regenerative braking force generating means,
The cooperative control means is configured to reduce the hydraulic braking force to be smaller than the braking operation characteristic when the charging rate of the battery detected by the charging rate detecting means is less than a predetermined charging rate set to be smaller than full charge. And controlling the regenerative braking force to be equal to or less than the braking force corresponding to the difference between the braking operation characteristic and the hydraulic braking force, and until the sum of the hydraulic braking force and the regenerative braking force reaches the required braking force. A vehicle control device for increasing power and increasing the hydraulic braking force and decreasing the regenerative braking force after the sum of the hydraulic braking force and the regenerative braking force reaches the required braking force .   The control device for a vehicle according to claim 1, wherein the cooperative control means sets an increasing rate of the regenerative braking force to be smaller than an increasing rate of the hydraulic braking force. The method according to claim 1, wherein the cooperative control unit prohibits the application of the regenerative braking force after a predetermined period has elapsed after the sum of the hydraulic braking force and the regenerative braking force reaches the required braking force. 4. The control device for a vehicle according to any one of the preceding claims. After the sum of the hydraulic braking force and the regenerative braking force reaches the required braking force, the coordination control means performs the request control when the sum of the hydraulic braking force and the regenerative braking force reaches the required braking force. the vehicle control device according to claim 1 or 2, wherein the controller controls the regenerative braking force below the braking force difference equivalent to the hydraulic braking force and power. The vehicle control device according to any one of claims 1 to 4, wherein the cooperative control means controls the regenerative braking force to a braking force corresponding to a difference between the braking operation characteristic and a hydraulic braking force. .