JP5245886B2 - Regenerative cooperative brake control device and regenerative cooperative brake control method - Google Patents

Description

  The present invention relates to a technology for regenerative cooperative brake control in which a target deceleration is generated by a friction braking torque and a regenerative braking torque corresponding to a hydraulic pressure.

As a conventional regenerative cooperative brake control device, for example, there is a device described in Patent Document 1. The device described in Patent Document 1 is a so-called in-line regenerative cooperative brake control device that causes a hydraulic brake device and a regenerative brake device to operate in a coordinated manner. Then, control is performed such that the sum of the basic hydraulic braking torque by the hydraulic brake device and the regenerative braking torque by the regenerative braking device becomes the target braking torque calculated according to the brake operation state. Note that braking by the regenerative braking device is preferentially used.
Here, there is also a regenerative cooperative brake control device that controls the basic hydraulic braking torque by a brake-by-wire system. However, an in-line regenerative cooperative brake control device in which a master cylinder and a wheel cylinder are connected is less expensive.

JP 2006-96218 A

In the inline regenerative cooperative brake control device, in order to change the ratio between the basic hydraulic braking torque and the regenerative braking torque, for example, if the regenerative braking torque is reduced, the basic hydraulic braking torque is increased accordingly. Control. At this time, when the hydraulic pressure increase control of the wheel cylinder is performed, the hydraulic fluid is sucked from the master cylinder. Therefore, even if the driver does not change the pedal operation, the stroke amount of the brake pedal changes. This also leads to fluctuations in the master cylinder pressure. In this way, when the stroke amount of the brake pedal and the master cylinder pressure change, the target deceleration changes accordingly. In this way, the braking torque varies at the time of regeneration switching.
The present invention has been made paying attention to the above points, and an object of the present invention is to suppress fluctuations in braking torque during regenerative switching in a so-called in-line regenerative cooperative brake control device.

  In order to solve the above-mentioned problem, the in-line regenerative cooperative brake control according to the present invention is performed according to the pedal stroke of the brake pedal or the fluctuation amount of the master cylinder pressure that is estimated to have occurred other than the operation of the brake pedal by the driver. , Correct the target deceleration.

  The present invention corrects the target deceleration by the amount of variation that occurs in accordance with the change in regenerative braking torque, thereby suppressing the variation in braking torque that occurs during regenerative switching.

1 is an overall system diagram showing a hybrid vehicle to which a regenerative cooperative brake control device of a first embodiment is applied. It is an alignment chart which shows each vehicle mode in the hybrid vehicle to which the regeneration cooperation brake control apparatus of 1st Embodiment was applied. It is a figure which shows the structure of a hydraulic brake device. It is a figure explaining the process of the brake controller which concerns on 1st Embodiment. It is a control block diagram which calculates | requires the target value of regenerative braking. It is a figure which shows the relationship between a pressure difference and a liquid quantity fluctuation amount. It is a figure which shows an example of the relationship between the change of the effective regenerative torque T (t), and the corrected amount of target deceleration G (t). FIG. 2 is a driving force performance characteristic diagram and a driving force conceptual diagram in a hybrid vehicle to which the regenerative cooperative brake control device of the first embodiment is applied. It is a figure showing the braking torque performance by the regeneration cooperation in the hybrid vehicle to which the regeneration cooperation brake control device of the first embodiment is applied. It is a figure showing the braking torque performance by the regeneration cooperation in the hybrid vehicle to which the regeneration cooperation brake control device of the first embodiment is applied. It is a figure which shows the example of a conventional time chart. It is a figure explaining the process of the brake controller which concerns on 2nd Embodiment. It is a figure explaining the weighting coefficient K1.

(First embodiment)
Next, a first embodiment of the present invention will be described with reference to the drawings.
(Constitution)
First, an example of a drive system configuration of a hybrid vehicle will be described.
FIG. 1 is an overall system diagram showing a drive system of a hybrid vehicle to which the regenerative cooperative brake control device of this embodiment is applied.
As shown in FIG. 1, the drive system of this hybrid vehicle has an engine E, a first motor generator MG1 (generator), a second motor generator MG2, an output sprocket OS, and a power split mechanism TM. .
The engine E controls the valve opening degree of the throttle valve and the like based on a control command from the engine controller 1 described later. The engine E is, for example, a gasoline engine or a diesel engine.

  The first motor generator MG1 and the second motor generator MG2 are, for example, synchronous motor generators in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator. The first motor generator MG1 and the second motor generator MG2 are independently controlled by applying a three-phase alternating current generated by the power control unit 3 based on a control command from a motor controller 2 described later.

  Both the motor generators MG1 and MG2 can also operate as electric motors that are driven to rotate by receiving power supplied from the battery 4 (hereinafter, this state is referred to as “powering”). Further, both the motor generators MG1 and MG2 function as a generator for generating electromotive force at both ends of the stator coil when the rotor is rotated by an external force, and can also charge the battery 4 with electric power. (Hereinafter, this operation state is called regeneration.)

The power split mechanism TM is configured by a simple planetary gear having a sun gear S, a pinion P, a ring gear R, and a pinion carrier PC.
The connection relationship of the input / output members with respect to the three rotating elements (sun gear S, ring gear R, and pinion carrier PC) of the simple planetary gear will be described. A first motor generator MG1 is connected to the sun gear S. A second motor generator MG2 and an output sprocket OS are connected to the ring gear R. The engine E is connected to the pinion carrier PC via an engine damper ED. The output sprocket OS is connected to the left and right front wheels via a chain belt CB, a differential (not shown), and a drive shaft.

  Due to the above connection relationship, the first motor generator MG1 (sun gear S), the engine E (planet carrier PC), the second motor generator MG2 and the output sprocket OS (ring gear R) are arranged in this order on the alignment chart shown in FIG. It is possible to introduce a rigid lever model (a relationship in which three rotational speeds are always connected by a straight line) that can simply express the dynamic operation of a simple planetary gear.

  Here, the “collinear diagram” is a velocity diagram that is used in a method that is obtained by a simpler and easier-to-understand drawing instead of a method that is obtained by an equation when considering the gear ratio of the differential gear. The vertical axis represents the rotational speed (rotational speed) of each rotating element, the horizontal axis represents each rotating element, and the interval between the rotating elements is a collinear lever ratio based on the gear ratio λ of the sun gear S and the ring gear R. It is arranged so as to be (1: λ).

Next, the configuration of the brake hydraulic brake device will be described with reference to FIG.
In FIG. 3, reference numeral 1 denotes a brake pedal 30. The driver operates the brake pedal 30 to instruct the required braking torque. The brake pedal 30 is connected to the master cylinder 34 through a negative pressure booster 31. The negative pressure booster 31 boosts and supplies the braking pressure (pedal depression force) corresponding to the depression amount of the brake pedal 30 to the master cylinder 34. However, in this embodiment, the boosting force by the negative pressure booster 31 is limited, and the braking pressure to the master cylinder 34 is adjusted to be smaller than the pedal effort. Reference numeral 35 denotes a reservoir of control fluid.

The master cylinder 34 is connected to the wheel cylinders 20 to 23 of each wheel through a pipe line constituting the fluid pressure circuit 36. A proportional electromagnetic valve 37 for fluid pressure control is inserted on the upstream side of the conduit. FIG. 3 shows a state in which the proportional solenoid valve 37 for fluid pressure control is not energized, and shows a state in which the fluid in the master cylinder 34 is supplied to the wheel cylinders 20 to 23 as they are.
The fluid pressure control proportional electromagnetic valve 37 adjusts the fluid (fluid pressure) supplied from the master cylinder 34 to the wheel cylinders 20 to 23 by the control current from the brake controller 5.

In addition, a brake control pump 38 is provided in the pipeline. The brake control pump 38 has a suction port connected to the master cylinder 34 and a discharge port communicating with the wheel cylinders 20-23. The brake control pump 38 increases the cylinder pressure of the wheel cylinders 20 to 23 based on a control command from the brake controller 5.
It should be noted that, for the above-mentioned pipe line, a proportional solenoid valve for fluid pressure control for pressure increase for ABS control and other controls (hereinafter referred to as a solenoid valve for pressure increase), and a proportional solenoid for fluid pressure control for pressure reduction. A valve (hereinafter referred to as a pressure reducing electromagnetic valve) may be provided, and the braking fluid pressure of each wheel cylinder 20 to 23 may be individually controlled by the electromagnetic valve.

Further, the output pressure of the master cylinder 34 (master cylinder pressure MCP: driver's required braking amount) is detected by the master cylinder pressure sensor 17, and the detection signal is supplied to the brake controller 5. Further, the brake fluid pressure of each wheel cylinder 20 to 23 is detected by the pressure sensor 40, and the detection signal is also supplied to the brake controller 5.
Next, the control system of the hybrid vehicle will be described.

As shown in FIG. 1, the control system of the hybrid vehicle in this embodiment includes an engine controller 1, a motor controller 2, a power control unit 3, a battery 4 (secondary battery), a brake controller 5, and an integrated controller. 6.
The integrated controller 6 receives input information from an accelerator opening sensor 7, a vehicle speed sensor 8, an engine speed sensor 9, a first motor generator speed sensor 10, and a second motor generator speed sensor 11. To do.

  The integrated controller 6 manages the energy consumption of the entire vehicle and bears a function for running the vehicle with the highest efficiency. That is, the integrated controller 6 performs engine operating point control by a control command to the engine controller 1 during acceleration traveling or the like. Further, the motor generator operating point control is performed by a control command to the motor controller 2 at the time of stopping, running, braking, or the like. The integrated controller 6 includes an accelerator opening AP, a vehicle speed VSP, an engine speed Ne, a first motor generator speed N1, and a second motor generator speed N2 from the sensors 7, 8, 9, 10, and 11. input. And based on these input information, a predetermined calculation process is performed and the control command by the process result is output to the engine controller 1 and the motor controller 2. FIG. The integrated controller 6 and the engine controller 1, the integrated controller 6 and the motor controller 2, the integrated controller 6 and the brake controller 5, etc. are connected by bidirectional communication lines 24, 25 and 26, respectively, for information exchange.

  The engine controller 1 outputs, for example, a command for controlling the engine operating point (Ne, Te) to a throttle valve actuator (not shown) in accordance with a target engine torque command or the like from the integrated controller 6. Here, the integrated controller 6 calculates a target engine torque command and the like based on the accelerator opening AP from the accelerator opening sensor 7 and the engine speed Ne from the engine speed sensor 9.

  The motor controller 2 calculates a command for controlling the motor operating point (N1, T1) of the first motor generator MG1 in accordance with a target motor generator torque command or the like from the integrated controller 6. Independently, a command for controlling the motor operating point (N2, T2) of the second motor generator MG2 is calculated according to the target motor generator torque command or the like. These calculated commands are output to the power control unit 3. The motor controller 2 uses information on the battery SOC that represents the state of charge of the battery 4. Further, the integrated controller 6 obtains the target motor generator torque command and the like based on the motor generator rotational speeds N1 and N2 from the both motor generator rotational speed sensors 10 and 11 by the resolver.

  The power control unit 3 includes a joint box (not shown), a boost converter, a drive motor inverter, and a generator generator inverter. Power control unit 3 constitutes a power supply system high voltage system that can supply power to both motor generators MG1 and MG2 with less current. A drive motor inverter is connected to the stator coil of the second motor generator MG2. A generator generator inverter is connected to the stator coil of the first motor generator MG1. In addition, a battery 4 that is discharged during power running and charged during regeneration is connected to the joint box.

Further, the power control unit 3 obtains the effective regenerative torque T (t) and outputs the effective regenerative torque T (t) to the brake controller 5.
The brake controller 5 includes a front left wheel speed sensor 12, a front right wheel speed sensor 13, a rear left wheel speed sensor 14, a rear right wheel speed sensor 15, a master cylinder pressure sensor 17, and a brake stroke sensor 18. And input information. The brake controller 5 performs regenerative brake cooperative control by issuing a control command to the integrated controller 6 and a control command to the brake hydraulic pressure unit 19 during braking by operating the engine brake or the brake pedal 30.

The processing of the brake controller 5 will be described with reference to FIG.
The brake controller 5 operates at a predetermined sampling cycle. First, in step S10, the wheel speed information from the wheel speed sensors 12, 13, 14, and 15 and the master cylinder pressure sensor 17 and the brake stroke sensor 18 are used. The braking operation amount information is input.
Next, in step S20, a target deceleration G (t) is calculated based on at least one of the master cylinder pressure MCP and the pedal stroke amount of the brake pedal 30.

Next, in step S30, the maximum regenerative torque Tmax (t), which is the upper limit value of the regenerative torque, is calculated from the vehicle speed, a control command is output to the integrated controller 6, and the process proceeds to step S40.
Here, calculation of the maximum regenerative torque Tmax (t) performed in step S30 will be described. This process is performed in a regeneration control block as shown in FIG.
As shown in FIG. 5, this regenerative control block includes a required regenerative torque calculation module 41, a required regenerative torque limit calculation unit 42, and a required regenerative torque limit selection module 43.
The required regenerative torque calculation module 41 inputs the master cylinder pressure MCP and the brake stroke S, and calculates the required regenerative torque REGE based on these information.

The requested regenerative torque limit calculation unit 42 calculates a regenerative torque upper limit value REGELIM based on vehicle speed information and the like. For example, when the accelerator is off and the coast braking is shifted to the creep state, the upper limit of the regenerative torque is calculated so as to gradually decrease toward zero. In addition, the upper limit value of the regenerative torque is limited depending on the charging rate and temperature of the battery.
The required regenerative torque limit selection module 43 receives the required regenerative torque REGE and the regenerative torque upper limit value REGELM, selects the regenerative torque REGEMIN after the limit by select low, and filters the upper limit value and lower limit value to obtain the maximum value. The regenerative torque Tmax (t) is calculated and output to the integrated controller 6.

In step S40, the effective regenerative torque T (t) is input and the process proceeds to step S50.
Next, in step S50, it is determined or estimated whether or not the changing speed of the effective regenerative torque T (t) is equal to or higher than a predetermined speed. When it is determined or estimated that the change speed of the effective regenerative torque T (t) is equal to or higher than the predetermined change speed, the process proceeds to step S60. On the other hand, when the change speed of the effective regenerative torque T (t) is determined or estimated to be less than the predetermined speed, the process proceeds to step S120.

The predetermined speed is a minimum value estimated that the response of the friction brake cannot catch up when the regenerative torque is replaced with the friction braking torque. For example, it is set to 400 (Nm / sec).
In step S60, the wheel cylinder pressure P2 is acquired based on the detection signal from the pressure sensor 40.
Next, in step S70, a hydraulic pressure difference ΔP between the hydraulic pressure corresponding to the target deceleration G (t) and the wheel cylinder pressure P2 is calculated.
ΔP = (hydraulic pressure corresponding to target deceleration G (t)) − P2

  Next, in step S80, using the map as shown in FIG. 6, the hydraulic pressure difference ΔP is converted into the fluid amount fluctuation amount cc. Here, the wheel cylinder pressure P2 is a value corresponding to the current friction brake amount. The hydraulic pressure difference ΔP is a value corresponding to the regenerative torque. Although the case where the hydraulic pressure difference corresponding to the target deceleration G (t) is obtained is illustrated above, the present invention is not limited to this. The wheel cylinder pressure P2 may be converted into a value corresponding to the friction brake amount, and a value corresponding to the above ΔP may be obtained based on a difference from the target deceleration G (t). Although the unit is different, it is possible to obtain the same tendency value.

Here, when the fluctuation of the regenerative torque is large, the target deceleration G (t) before the correction is a value including the torque fluctuation. Then, the hydraulic pressure difference ΔP obtained by subtracting the actual cylinder pressure from the hydraulic pressure corresponding to the target deceleration including the fluctuation becomes a value corresponding to the regenerative torque.
The larger the regenerative torque, the smaller the sucked amount of the liquid amount due to the fluctuation of the regenerative torque, and the smaller the regenerative torque, the larger the sucked amount of the liquid amount due to the fluctuation of the regenerative torque. Based on this, in FIG. 6, the fluid amount variation amount cc is set to become smaller as the fluid pressure difference ΔP becomes larger.

Next, in step S90, the fluid amount fluctuation amount cc is converted into a master stroke difference ΔS based on specification values such as the piston diameter of the master cylinder.
Next, in step S100, the master pedal stroke difference ΔS is corrected from the actual pedal stroke amount of the brake pedal 30 (subtracted by ΔS), and the corrected pedal stroke amount Pst is calculated.
Next, in step S110, the target deceleration G (t) is calculated again using the corrected pedal stroke amount Pst. The target deceleration G (t) may be calculated again by obtaining the master cylinder pressure fluctuation from the fluid quantity fluctuation amount cc and correcting the master cylinder pressure.

Next, in step S115, the friction braking torque F (t) is calculated based on the following formula, and the process proceeds to step S170.
F (t) = target deceleration G (t)-effective regenerative torque T (t)
On the other hand, when it is determined or estimated that the change speed of the regenerative torque is less than a predetermined value in step S50 and the process proceeds to step S120, the friction braking torque F (t) is calculated based on the following formula, and the process proceeds to step S130.
F (t) = target deceleration G (t)-effective regenerative torque T (t)

  In step S130, the amount of change ΔG of the target deceleration G (t) is estimated from the change rate ΔT of the effective regenerative torque T (t), and the process proceeds to step S70. This estimation is obtained by using a map between the change rate of the effective regenerative torque T (t) and the change amount ΔG of the target deceleration G (t) obtained by experiments and the like. The change rate ΔT of the effective regenerative torque T (t) and the change amount ΔG of the target deceleration G (t) have a relationship as shown in FIG.

In step S140, it is determined whether the target deceleration G (t) is greater than or equal to a predetermined threshold value. If it is determined that the threshold value is equal to or greater than the predetermined threshold value, the process proceeds to step S80. If it is determined that the threshold value is less than the predetermined threshold value, the process proceeds to step S170.
The predetermined threshold is set to a value slightly larger than the target deceleration G (t) corresponding to the port idle, for example, for the piston stroke of the master cylinder 34. In such a state where the target deceleration G (t) is small, the variation dependency of the master cylinder pressure MCP due to the pedal stroke is large, and the possibility of variation due to the driver's operation is large. Is.

In step S150, the target deceleration G (t) is corrected by the change amount ΔG as shown in the following equation, and the process proceeds to step S160.
Correction target deceleration G ′ (t) = target deceleration G (t) + change amount ΔG
In step S160, the friction braking torque F (t) is calculated again based on the following formula, and the process proceeds to step S170.
F (t) = corrected target deceleration G ′ (t) −effective regenerative torque T (t)
In step S170, the target control fluid pressure of the wheel cylinders 20 to 23 corresponding to the friction braking torque F (t) is calculated, and the process proceeds to step S180.

In step S180, the master pump pressure BPu is calculated by subtracting the master cylinder pressure MCP from the target brake fluid pressure, and a command value corresponding to the target pump pressure is output to the brake control pump 38 of the brake hydraulic pressure unit 19. It will return later. Note that the target control fluid pressure of the wheel cylinders 20 to 23 can be adjusted to be small by the proportional solenoid valve 37 for fluid pressure control.
Thus, the control fluid pressure of each wheel cylinder 20-23 is controlled individually, and the braking torque by the friction load of a desired magnitude | size is provided to a wheel via a disk rotor.

(Operation)
First, driving force performance will be described.
As shown in FIG. 8 (b), the driving force of the hybrid vehicle includes an engine direct driving force (a driving force obtained by subtracting the generator driving amount from the engine total driving force) and a motor driving force (both motor generators MG1, MG2). The driving force by the sum of As shown in FIG. 8A, the maximum driving force is configured such that the motor driving force occupies more as the vehicle speed becomes lower. In this way, the vehicle does not have a transmission and travels by applying the direct drive force of the engine E and the motor drive force converted electrically. For this reason, the driving force can be controlled in a seamless and responsive manner from the low speed to the high speed, from the state where the power of steady driving is low to the full power where the accelerator pedal is fully opened (torque on demand).

  In the hybrid vehicle, the engine E, the motor generators MG1, MG2, and the left and right front tires are connected without a clutch via the power split mechanism TM. In addition, as described above, most of the engine power is converted into electric energy by a generator, and the vehicle is driven by a motor with high output and high response. For this reason, for example, when driving on a slippery road such as an ice burn, when the driving force of the vehicle changes suddenly due to tire slip or tire locking during braking, the power control unit 3 is protected from excessive current. Alternatively, it is necessary to protect parts from the pinion over-rotation of the power split mechanism TM. On the other hand, motor traction control that utilizes the high-output and high-response motor characteristics, developed from the component protection function, detects tire slip instantly, recovers its grip, and runs the vehicle safely. Is adopted.

Next, the vehicle mode will be described.
As shown in the alignment chart of FIG. 2, the hybrid vehicle has a “stop mode”, “start mode”, “engine start mode”, “steady travel mode”, and “acceleration mode”. .
In the “stop mode”, as shown in FIG. 2A, the engine E, the generator MG1, and the motor MG2 are stopped. In the “start mode”, as shown in FIG. 2 (2), the vehicle starts by driving the motor MG2. In the “engine start mode”, as shown in FIG. 2 (3), the sun gear S rotates and the engine E is started by the generator MG1 having a function as an engine starter. In the “steady travel mode”, as shown in FIG. 2 (4), the vehicle travels mainly by the engine E, and power generation is minimized in order to increase efficiency. In the “acceleration mode”, as shown in FIG. 2 (5), while increasing the number of revolutions of the engine E, power generation by the generator MG1 is started, and the driving power of the motor MG2 is increased using the power and the power of the battery 4. In addition, it accelerates.

In reverse running, in the “steady running mode” shown in FIG. 2 (4), if the rotational speed of the generator MG1 is increased while the increase in the rotational speed of the engine E is suppressed, the rotational speed of the motor MG2 becomes negative. Transition and reverse travel can be achieved.
At the time of start-up, when the ignition key is turned, the engine E starts, and after the engine E is warmed up, the engine E stops immediately. When starting or at a light load, when starting or when going down a gentle hill that runs at a very low speed, the fuel is cut in a region where the engine efficiency is poor, and the engine is stopped and the vehicle is driven by the motor MG2. During normal travel, the driving force of the engine E is driven by the power split mechanism TM, one of which directly drives the wheel, the other drives the generator MG1, and assists the motor TM2. At the time of full open acceleration, power is supplied from the battery 4 and further driving force is added.

  At the time of deceleration or braking, the wheel drives the motor TM2 and acts as a generator to perform regenerative power generation. The collected electrical energy is stored in the battery 4. When the charge amount of the battery 4 decreases, the generator MG1 is driven by the engine E and charging is started. When the vehicle is stopped, the engine E is automatically stopped except when the air conditioner is used or when the battery is charged.

Next, the braking torque performance will be described.
In the above-described hybrid vehicle, when braking by the engine brake or the foot brake, the kinetic energy of the vehicle is converted into electric energy and recovered by the battery 4 by operating the second motor generator MG2 that operates as a motor as a generator. The regenerative braking system is reused.
Here, the regenerative brake cooperative control employed in the hybrid vehicle of the present embodiment limits the master cylinder pressure MCP of the master cylinder 34 with respect to the depression amount of the brake pedal 30, as shown in FIGS. As a result, the regenerative braking (effective regenerative torque T (t)) is given priority over the driver's required braking torque, and the regenerative portion is expanded to the maximum extent as long as it can be covered by the regenerative portion. As a result, energy recovery efficiency is high particularly in a traveling pattern in which acceleration and deceleration are repeated, and energy recovery by regenerative braking is realized up to a lower vehicle speed.

  In the present embodiment, the master cylinder 34 and the wheel cylinders 20 to 23 are connected to make the apparatus inexpensive. At this time, the fluid pressure supplied from the master cylinder 34 to the wheel cylinders 20 to 23 is suppressed, and the pressure cannot be controlled. In addition, the effective regenerative torque T (t) may deviate from the maximum regenerative torque Tmax (t). Therefore, in the present embodiment, the required braking torque (target deceleration G (t)) is secured by controlling the brake control pump 38.

Here, as shown in the time chart of FIG. 11, when the pedal depression force of the brake pedal 30 is constant, for example, when the accelerator is turned off and the effective regenerative torque T (t) is limited, the shortage is compensated. In addition, the discharge pressure of the brake control pump 38 increases.
That is, when the regenerative side torque changes, the friction braking side torque changes so as to compensate for it, thereby attempting to achieve the target deceleration. At this time, the brake pedal, the master cylinder, and the wheel cylinder are mechanically connected. For this reason, even if the amount of brake operation is constant and the target deceleration requested by the driver is constant, the brake pedal fluctuates according to the increase or decrease of the fluid amount on the wheel cylinder side due to the torque change on the friction braking side, In other words, the brake pedal is sucked in and back.

  That is, since the brake control pump 38 sucks the hydraulic fluid in the master cylinder 34, the master cylinder pressure MCP decreases even though the pedal depression force of the brake pedal 30 does not change. For this reason, the target deceleration G (t) decreases, and if it is left as it is, a fluctuation occurs in the decreasing direction with respect to the deceleration requested by the driver. Similarly, when the effective regenerative torque T (t) changes in the increasing direction, the change occurs in the increasing direction with respect to the deceleration requested by the driver as it is.

The braking fluctuation that causes the brake pedal fluctuation becomes significant especially when the change speed of the regenerative torque exceeds a predetermined value and exceeds the change speed of the brake response on the friction braking side.
For this reason, in this embodiment, when the change speed of the regenerative torque is greater than or equal to a predetermined value, the target reduction is performed so as to correct the amount of hydraulic pressure corresponding to the amount of change in the brake pedal other than the driver's operation of the brake pedal. Correct the speed.
As a result, fluctuations in the target deceleration that occur remarkably when the change speed of the regenerative torque is greater than or equal to a predetermined value are suppressed.

Even if the regenerative torque change speed is less than a predetermined value, the target deceleration varies. Therefore, even if the change speed of the regenerative torque is less than a predetermined value, the deceleration requested by the driver is corrected by correcting the target deceleration G (t) according to the variation of the effective regenerative torque T (t). Reduces fluctuations in braking. That is, when the effective regenerative torque T (t) is changed in a decreasing direction, correction for increasing the target deceleration G (t) is performed. On the other hand, when the effective regenerative torque T (t) is changed in the increasing direction, correction for reducing the target deceleration G (t) is performed.
Here, the change speed of the regenerative torque being greater than or equal to a predetermined value is likely to occur when the vehicle speed is low. This is because the regenerative torque decreases when the vehicle speed is low. In addition, when the transmission shifts, the regenerative torque change speed tends to be greater than or equal to a predetermined value.

  Here, the brake control pump 38 constitutes a hydraulic pressure adjusting means. The power control unit 3 constitutes an effective regeneration amount detection means. Motor generators MG1, MG2, power control unit 3, motor controller, and battery 4 constitute regenerative braking means. Step S20 calculates the target deceleration G (t). Steps S120 and S115 constitute friction braking torque calculation means. Step S170 constitutes a hydraulic pressure control means. The change amount ΔG constitutes a deceleration correction amount. Steps S60 to S90 constitute fluctuation amount estimation means. Steps S100 and S110 constitute first target deceleration correction means. Steps S120 to S150 constitute second target deceleration correction means.

(Effect of this embodiment)
(1) An in-line regenerative cooperative brake control device is assumed. The hydraulic pressure adjusting means increases or decreases the hydraulic pressure supplied from the master cylinder to the wheel cylinder. The regenerative braking means generates regenerative braking by applying an electrical load to the wheels. The effective regenerative amount detection means obtains an effective regenerative torque by the regenerative braking means. The target deceleration calculating means calculates the target deceleration based on at least one of the pedal stroke and the master cylinder pressure. The friction braking torque calculating means calculates a target friction braking torque obtained by subtracting the effective regenerative torque from the target deceleration. The hydraulic pressure control means increases or decreases the hydraulic pressure via the hydraulic pressure adjustment means so that the wheel cylinder pressure corresponds to the target friction braking torque calculated by the friction braking torque calculation means. The fluctuation amount estimation means estimates the fluctuation amount of the brake pedal or master cylinder pressure other than the operation of the brake pedal by the driver. The first target deceleration correction means corrects the brake pedal or the master cylinder pressure according to the fluctuation amount estimated by the fluctuation amount estimation means when the change speed of the effective regenerative torque is equal to or higher than a predetermined speed, The target deceleration calculated by the target deceleration calculation means is corrected.

By correcting the target deceleration by a fluid amount change corresponding to a predetermined change in the regenerative braking torque, fluctuations in the braking torque during regenerative switching are suppressed. In particular, by correcting when the change speed of the effective regenerative torque at which the torque fluctuation appears remarkably is equal to or higher than a predetermined speed, it is possible to suppress the torque fluctuation when the torque fluctuation exceeds a predetermined value.
That is, even when the master cylinder pressure MCP fluctuates when so-called regenerative switching is performed in which the ratio of regenerative braking to friction braking with respect to the target deceleration G (t) is performed, the target for deceleration actually requested by the driver A change in the deceleration G (t) can be suppressed. As a result, even in a regenerative cooperative braking system using a fluid braking system (braking system that is not a BBW system) in which the master cylinder 34 and the wheel cylinders 20 to 23 are communicated with each other, fluctuations in deceleration can be suppressed. .

(2) The fluctuation amount estimating means estimates the fluctuation amount based on the target deceleration before correction and the hydraulic pressure of the wheel cylinder.
As a result, it is possible to estimate the fluctuation amount of the brake pedal or master cylinder pressure other than the operation of the brake pedal by the driver.
(3) The second target deceleration correction means estimates a deceleration correction amount based on the change speed of the effective regenerative torque, and the target deceleration calculated by the target deceleration calculation means based on the estimated deceleration correction amount. Alternatively, the target friction braking torque calculated by the friction braking torque calculating means is corrected.
As a result, even when the first target deceleration correction means is not operating or when the correction by the first target deceleration correction means is small, it is possible to suppress torque fluctuation.

(4) The second target deceleration correction means executes the correction process when the change speed of the effective regenerative torque is less than a predetermined speed.
Thus, when the first target deceleration correction means is not operating, the second target deceleration correction means corrects it.
As a result, it is possible to suppress torque fluctuations even when the effective regenerative torque change speed is less than a predetermined speed.
(5) Even if the effective regenerative torque T (t) varies, correction by the second target deceleration correction means is not performed when the target deceleration G (t) is small. When the target deceleration G (t) is small, the variation dependency due to the pedal stroke is high. Therefore, there is a high possibility that the driver has actually operated the brake pedal 30. Can be avoided.

(Modification)
(1) In the above embodiment, the second target deceleration corrects the target deceleration itself. Instead, the friction brake torque correction amount F (t) once calculated may be corrected by obtaining the correction amount of the friction braking torque from the change speed of the effective regenerative torque.
(Second Embodiment)
Next, a second embodiment will be described with reference to the drawings. Note that components similar to those in the above-described embodiment will be described with the same reference numerals.

(Constitution)
In the first embodiment, when the change speed of the regenerative torque is equal to or higher than the predetermined speed, the target deceleration is corrected by the first target deceleration correction means, and when the change speed of the regenerative torque is less than the predetermined speed, Correction is performed by the second target deceleration correction means.
In contrast, in the present embodiment, the first target deceleration corrected by the first target deceleration correction means and the second target deceleration corrected by the second target deceleration correction means. Based on the speed, the final target deceleration is calculated.

Next, the process of the brake controller of this embodiment will be described with reference to FIG.
The brake controller operates at a predetermined sampling period.
The process of step S10-step S40 is the same as that of the said 1st embodiment.
In the present embodiment, when the process of step S40 ends, the processes of steps S60 to S110 are performed as they are. Thus, the first target deceleration G1 (t) after being corrected by the first target deceleration correction means is calculated.

Subsequently, the processes of steps S120, S130, and S150 are performed to calculate the second target deceleration G ′ (t) after being corrected by the third target deceleration correcting means.
Next, in step S200, a weighting coefficient K1 is obtained based on the changing speed of the effective regenerative torque T (t). The weighting coefficient K1 is obtained from the map shown in FIG. That is, the weighting coefficient K1 is set so as to increase as the change rate of the effective regenerative torque T (t) increases. When the change speed of the effective regenerative torque T (t) is equal to or higher than a predetermined speed, the weighting coefficient K1 is 1 It becomes.

Further, the slope θ of the characteristic line A0 that determines the coefficient K1 is set so as to increase as the change acceleration of the effective regenerative torque T (t) increases. That is, the coefficient K1 increases as the change acceleration of the effective regenerative torque T (t) increases.
Here, the map in FIG. 13 is set so that the characteristic line representing the relationship between the change speed of the effective regenerative torque T (t) and the coefficient K1 is linear. In the case of a stepped transmission, it is preferable that the characteristic line is an upwardly curved arc-like curve as indicated by reference numeral A1. Further, when the transmission is a CVT, it is preferable to form a downwardly convex arc shape as indicated by reference numeral A2.

In step S210, the final target damping force is calculated based on the first target damping force and the second target damping force by weighting with the coefficient K1 as in the following equation.
G (t) = K1 * G1 (t) + (1-K1) * G '(t)
Next, in step S220, the friction braking torque F (t) is calculated based on the following formula, and the process proceeds to step S170.
F (t) = target deceleration G (t)-effective regenerative torque T (t)

In step S170, the target control fluid pressure of the wheel cylinders 20 to 23 corresponding to the friction braking torque F (t) is calculated, and the process proceeds to step S180.
In step S180, the master pump pressure BPu is calculated by subtracting the master cylinder pressure MCP from the target brake fluid pressure, and a command value corresponding to the target pump pressure is output to the brake control pump 38 of the brake hydraulic pressure unit 19. It will return later. Note that the target control fluid pressure of the wheel cylinders 20 to 23 can be adjusted to be small by the proportional solenoid valve 37 for fluid pressure control.
Thus, the control fluid pressure of each wheel cylinder 20-23 is controlled individually, and the braking torque by the friction load of a desired magnitude | size is provided to a wheel via a disk rotor.

(Operation / Action)
In the present embodiment, the second target deceleration calculated based on the first target deceleration corrected according to the change in the brake pedal due to the hydraulic pressure change and the deceleration correction amount estimated based on the change speed of the effective regenerative torque. Is weighted by the coefficient K1 to calculate the final target deceleration.
At this time, the weighting of the first target deceleration is increased by increasing the coefficient K1 as the change speed and change acceleration of the regenerative torque increase.
Steps S200 and S210 constitute target deceleration adjusting means.

(Effect of this embodiment)
(1) The first target deceleration correction means corrects the target deceleration calculated by the target deceleration calculation means in accordance with the estimated fluctuation amount regardless of the change speed of the effective regenerative torque. Find the target deceleration for. The second target deceleration correction means obtains a second target deceleration obtained by correcting the target deceleration calculated by the target deceleration calculation means based on the deceleration correction amount. Then, the target deceleration adjusting means converts the first target deceleration and the second target deceleration to the change speed of the effective regenerative torque based on the first target deceleration and the second target deceleration. Based on the weight, the final target deceleration is calculated. At this time, the target deceleration adjusting means increases the weighting on the first target deceleration side as the change speed of the effective regenerative torque increases.
Accordingly, it is possible to appropriately distribute the correction amount of the torque fluctuation to the first first deceleration and the second target deceleration according to the change speed of the effective regenerative torque.

(2) The weighting is corrected so that the weighting on the first target deceleration side increases as the change acceleration of the effective regenerative torque increases.
Thereby, the weight of the first target deceleration can be increased as the change acceleration of the effective regenerative torque is larger.
(3) When the transmission is a stepped AT, a sudden change in rotation occurs every time a change is made, and the sudden change amount is large. For this reason, when a shift occurs, it is desired to make correction with emphasis on hydraulic pressure quickly. For this reason, the characteristic line in FIG. 13 is set as A1. That is, at the initial stage of the change in the effective regenerative torque, the increment of the first target deceleration weighting is increased.

(4) When the transmission is CVT, there is basically no sudden change according to the shift. Therefore, it is preferable to make correction with emphasis on hydraulic pressure only when the failure is irregular. For this reason, the characteristic line in FIG. 13 is set as A1. That is, when the change speed of the effective regenerative torque is small, the increment of the first target deceleration weight is reduced, and when the change speed of the effective regenerative torque becomes larger than the predetermined value, the increment of the first target deceleration weight is increased at once. Try to make it bigger.
(Modification)
(1) In all the above embodiments, the case where the motor that performs regeneration is coupled to the engine is illustrated, but the motor that performs regeneration may be independent of the engine.

20-23 Wheel cylinder 5 Brake controller 6 Integrated controller 17 Master cylinder pressure sensor 18 Brake stroke sensor 19 Brake hydraulic pressure unit 30 Brake pedal 34 Master cylinder 36 Fluid pressure circuit 37 Proportional solenoid valve for fluid pressure control 38 Pump for braking control 40 Pressure sensor 41 Required regenerative torque calculation module 42 Required regenerative torque limit calculation unit 43 Required regenerative torque limit selection module A0, A1, A2 Characteristic line AP Accelerator opening BPu Target pump pressure cc Fluid amount fluctuation amount F Friction brake amount G Target deceleration G1 First target deceleration G ′ Second target deceleration K1 Weighting coefficient MCP Master cylinder pressure Pst Pedal stroke amount T Effective regenerative torque ΔP Hydraulic pressure difference ΔS Master stroke difference ΔT Speed of change

Claims (6)

A master cylinder that generates a master cylinder pressure corresponding to the pedal stroke of the brake pedal, a fluid pressure circuit that can supply the hydraulic pressure of the master cylinder to a wheel cylinder of a wheel, and a master provided in the fluid pressure circuit Hydraulic pressure adjusting means capable of increasing / decreasing the hydraulic pressure supplied from the cylinder to the wheel cylinder, regenerative braking means for generating regenerative braking by applying an electric load to the wheel, and effective regenerative torque for obtaining an effective regenerative torque by the regenerative braking means A quantity detection means;
Target deceleration calculating means for calculating a target deceleration based on at least one of the pedal stroke and the master cylinder pressure;
Friction braking torque calculating means for calculating a target friction braking torque obtained by subtracting the effective regenerative torque from the target deceleration;
Hydraulic pressure control means for increasing or decreasing the hydraulic pressure via the hydraulic pressure adjusting means so as to be the wheel cylinder pressure corresponding to the target friction braking torque calculated by the friction braking torque calculating means;
A fluctuation amount estimating means for estimating a fluctuation amount of a pedal stroke or a master cylinder pressure other than a brake pedal operation by a driver;
When the change speed of the effective regenerative torque is higher than the speed at which the friction brake can respond, the target deceleration calculation is performed by correcting the pedal stroke or the master cylinder pressure according to the fluctuation amount estimated by the fluctuation amount estimation means. First target deceleration correction means for correcting the target deceleration calculated by the means;
A deceleration correction amount is estimated based on the change speed of the effective regenerative torque, and the target deceleration calculated by the target deceleration calculation unit or the target friction calculated by the friction braking torque calculation unit is based on the estimated deceleration correction amount. Second target deceleration correction means for correcting braking torque;
A regenerative cooperative brake control device comprising:   The regenerative cooperative brake control device according to claim 1, wherein the fluctuation amount estimation means estimates the fluctuation amount based on a target deceleration before correction and a hydraulic pressure of the wheel cylinder.   The regenerative cooperative brake according to claim 1 or 2, wherein the second target deceleration correction means executes the correction process when the change speed of the effective regenerative torque is less than a predetermined speed. Control device. The first target deceleration correction means corrects the target deceleration calculated by the target deceleration calculation means in accordance with the estimated fluctuation amount regardless of the change speed of the effective regenerative torque. The second target deceleration correction means obtains a second target deceleration obtained by correcting the target deceleration calculated by the target deceleration calculation means based on the deceleration correction amount,
Based on the first target deceleration and the second target deceleration, the first target deceleration and the second target deceleration are weighted on the basis of the change speed of the effective regenerative torque to obtain a final target. Provided with target deceleration adjustment means for calculating deceleration,
The friction braking torque calculating means calculates a target friction braking torque obtained by subtracting the effective regenerative torque from the final target deceleration obtained by the target deceleration adjusting means,
The regeneration according to any one of claims 1 to 3, wherein the target deceleration adjusting means increases the weight of the first target deceleration as the change speed of the effective regeneration torque increases. Cooperative brake control device.   The regenerative cooperative brake control device according to claim 4, wherein the weighting is corrected so that the weighting of the first target deceleration increases as the change acceleration of the effective regenerative torque increases. The master cylinder generates a master cylinder pressure corresponding to the pedal stroke of the brake pedal, and the hydraulic pressure of the master cylinder is configured to be supplied to the wheel cylinder of the target wheel via the fluid pressure circuit. In contrast, a hydraulic pressure adjusting means capable of increasing or decreasing the hydraulic pressure supplied from the master cylinder to the wheel cylinder is provided.
A target deceleration calculated based on at least one of the pedal stroke and the master cylinder pressure, an effective regenerative torque generated by an electric load on the wheel, and a friction braking torque by control of the wheel cylinder pressure via the hydraulic pressure adjusting means, In the regenerative cooperative brake control method achieved by
When the change speed of the effective regenerative torque is determined to be equal to or higher than a predetermined speed, the target deceleration is corrected according to the amount of brake pedal fluctuation estimated to have occurred other than the operation of the brake pedal by the driver. Regenerative cooperative brake control method.
When the change speed of the effective regenerative torque is higher than the speed at which the friction brake can respond, the pedal stroke or master cylinder pressure is corrected according to the amount of change in the pedal stroke or master cylinder pressure other than the operation of the brake pedal by the driver. By correcting the target deceleration,
A regenerative cooperative brake control method, wherein a deceleration correction amount is estimated based on a change speed of the effective regenerative torque, and the target deceleration or the friction braking torque is corrected based on the estimated deceleration correction amount.

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