JP2020032982A - Brake control device for vehicle - Google Patents

Abstract

To provide a brake control device for a vehicle, which can impart a proper braking force to each wheel during braking of a traction vehicle for towing a vehicle to be towed.SOLUTION: A brake control device for a vehicle, which is mounted on a traction vehicle for towing a vehicle to be towed, comprises a calculation part that calculates a braking force of each wheel of the traction vehicle on the basis of a pushing force in a longitudinal direction of the vehicle, which is applied to the traction vehicle from the vehicle to be towed during the braking of the traction vehicle, and a braking control part that controls the braking of each wheel on the basis of the braking force.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a vehicle brake control device.

  2. Description of the Related Art Conventionally, brake control in a towing vehicle (for example, a tractor) for towing a towed vehicle (for example, a trailer) has been improved. This is because the towing vehicle is affected not only by the weight of the tow vehicle but also by the weight of the tow vehicle during braking when towing the tow vehicle compared to when the tow vehicle is not towing.

  Therefore, for example, there is a technique that determines whether or not the vehicle is in a towing state based on the actual traveling state of the towing vehicle, and changes the target deceleration during deceleration according to the determination result.

JP 2006-348840 A

  However, in the case of a towing vehicle, when braking during towing, not only the magnitude of the vertical load applied to each wheel of the towing vehicle, but also the ratio changes, so that when decelerating, It is not sufficient to simply change the target deceleration of the vehicle, and further improvement is desired.

  Therefore, one of the objects of the present invention is to provide a vehicle brake control device that can apply an appropriate braking force to each wheel when braking a tow vehicle that pulls a tow vehicle, for example.

  The present invention is, for example, a vehicular braking control device mounted on a tow vehicle for towing a towed vehicle, wherein the towing vehicle receives from the towed vehicle a pressing force in the vehicle longitudinal direction received from the towed vehicle during braking of the towed vehicle. A braking unit that calculates braking force of each wheel of the towing vehicle based on the braking force; and a braking control unit that controls braking of each wheel based on the braking force.

FIG. 1 is a diagram illustrating a schematic configuration of a vehicle equipped with an ECU that is a vehicle braking control device according to the first embodiment. FIG. 2 is a side view schematically illustrating the vehicle and the towed vehicle according to the first embodiment. FIG. 3 is a side view schematically illustrating the vehicle and the towed vehicle according to the first embodiment. FIG. 4 is a graph showing the ideal braking force distribution in the first embodiment. FIG. 5 is a flowchart illustrating an example of a control procedure performed by the ECU according to the first embodiment. FIG. 6 is a side view schematically showing a vehicle on a slope and a towed vehicle in the second embodiment.

  Hereinafter, exemplary embodiments of the present invention (first and second embodiments) will be disclosed. The configuration of the embodiment described below, and the operation and result (effect) provided by the configuration are examples. The present invention can be implemented by configurations other than those disclosed in the following embodiments. Further, according to the present invention, at least one of various effects (including derivative effects) obtained by the following configuration can be obtained.

(1st Embodiment)
First, a schematic configuration of a vehicle equipped with an ECU (Electronic Control Unit) 50, which is a vehicle braking control device according to the first embodiment, will be described with reference to FIG. FIG. 1 is a diagram illustrating a schematic configuration of a vehicle 100 equipped with an ECU 50 that is a vehicle braking control device according to the first embodiment. The vehicle 100 is a towing vehicle (for example, a tractor) for towing a towed vehicle 200 (for example, a trailer; see FIG. 2) having no braking function.

  As shown in FIG. 1, the vehicle 100 includes a driving force generation device 11 for running the vehicle 100, a steering device 12 for turning the front wheels FR and FL as steered wheels, and wheels FL, FR and RL. , RR (hereinafter, may be simply referred to as “wheels” without reference numerals) and a braking device 13 for applying a braking force.

  The driving force generation device 11 includes an engine 21 that generates a driving force based on the amount of operation of an accelerator pedal 20 by a driver, that is, an accelerator opening, and an automatic transmission 22 connected to an output shaft of the engine 21. Have been. Further, the driving force generating device 11 is provided with an accelerator opening sensor SE1 for detecting the accelerator opening. The driving force output from the engine 21 is transmitted from the automatic transmission 22 to the differential gear 23, and is distributed from the differential gear 23 to the front wheels FR and FL, which are driving wheels.

  The vehicle 100 is provided with a shift device 25 operated by a driver. When the range of the shift device 25 is the forward range, the automatic transmission 22 outputs a driving force in a direction for moving the vehicle 100 forward. On the other hand, when the range of shift device 25 is the reverse range, automatic transmission 22 outputs a driving force in the direction of causing vehicle 100 to move backward. Shift information such as whether the vehicle is in the forward range or the reverse range is transmitted to the ECU 50 as a vehicle brake control device that controls the brake device 13.

  The steering device 12 is provided with a steering shaft 31 to which a steering wheel 30 steered by a driver is fixed, and a steering actuator 32 connected to the steering shaft 31. Further, the steering device 12 is provided with a link mechanism 33 including a tie rod that can be moved in the left and right direction of the vehicle 100 by a steering actuator 32 and a link that steers the front wheels FL and FR by moving the tie rod. I have. Further, the steering device 12 is provided with a steering angle sensor SE2 that outputs a detection signal according to the steering angle of the steering 30 to the ECU 50. The steering angle sensor SE2 outputs, for example, a detection signal such that the steering angle becomes a positive value when the vehicle 100 is turned rightward, and outputs a steering signal when the vehicle 100 is turned leftward. A detection signal is output such that the angle becomes a negative value.

  The braking device 13 includes a hydraulic pressure generating device 41 that generates a brake hydraulic pressure according to a driver's operating force on the brake pedal 40, and a braking device 42a that is individually provided for each of the wheels FR, FL, RR, and RL. A brake actuator 43 connected to 42b, 42c, 42d is provided. The brake device 13 is provided with a brake switch SW1 that outputs a detection signal to the ECU 50 in accordance with the operation state (on or off) of the brake pedal 40 by the driver.

  The brake actuator 43 is configured to apply a braking force to the wheels FR, FL, RR, RL even when the driver does not operate the brake pedal 40. For example, the brake actuator 43 generates a pressure difference between the brake fluid pressure on the fluid pressure generating device 41 side and the brake fluid pressure in the wheel cylinders provided in the brake devices 42a, 42b, 42c, 42d. It includes a differential pressure regulating valve and an electric pump for supplying brake fluid into the wheel cylinder. Further, the brake actuator 43 is provided with various valves for individually adjusting the brake fluid pressure in each wheel cylinder. That is, the brake actuator 43 of the first embodiment can individually adjust the braking force on each of the wheels FR, FL, RR, RL.

  In addition to the accelerator opening sensor SE1, the steering angle sensor SE2, and the brake switch SW1, the ECU 50 includes wheel speed sensors SE3, SE4, SE5, SE6 for detecting the wheel speeds of the wheels FR, FL, RR, RL. Are electrically connected. The ECU 50 also includes a longitudinal acceleration sensor SE7 for detecting acceleration in the longitudinal direction of the vehicle 100 (hereinafter, referred to as “longitudinal acceleration”), and an acceleration in the lateral direction (vehicle width direction) of the vehicle 100 (hereinafter, “vehicle width direction”). , "Lateral acceleration") and a yaw rate sensor SE9 for detecting the yaw rate of the vehicle 100 are electrically connected.

  In addition, when the vehicle 100 accelerates when the road surface on which the vehicle 100 is traveling is a horizontal road, a detection signal is output from the longitudinal acceleration sensor SE7 such that the longitudinal acceleration becomes a positive value, and the vehicle 100 When decelerating, a detection signal is output such that the longitudinal acceleration has a negative value. When the vehicle 100 stops on a downhill, the center of gravity of the vehicle 100 moves to the front side, and the longitudinal acceleration calculated based on the detection signal from the longitudinal acceleration sensor SE7 has a negative value.

  Further, from the lateral acceleration sensor SE8 and the yaw rate sensor SE9, when the vehicle 100 turns right, the lateral acceleration and the yaw rate of the vehicle 100 take positive values, while the vehicle 100 turns left. In this case, detection signals are output such that the lateral acceleration and the yaw rate of the vehicle 100 become negative values.

  The ECU 50 may be incorporated in an ECU of any system mounted on the vehicle 100, or may be an independent ECU. The ECU 50 can include a CPU (Central Processing Unit), a controller, a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, and the like (not shown). The ECU 50 executes processing in accordance with the installed and loaded program, and can realize each function.

  The ECU 50 includes a processing unit 510 and a storage unit 520. The processing unit 510 includes an acquisition unit 511, an estimation unit 512, a calculation unit 513, and a braking control unit 514. That is, the ECU 50 can function as the acquisition unit 511, the estimation unit 512, the calculation unit 513, the brake control unit 514, and the like by executing the processing according to the program. The storage unit 520 stores data used in arithmetic processing of each unit, data of a result of the arithmetic processing, and the like. Note that at least a part of the function of each of the above units may be realized by hardware.

  The acquisition unit 511 acquires data (signal) from each of the sensors SE1 to SE9, the brake switch SW1, and the like.

  The estimating unit 512 estimates the vertical load of each wheel based on the pressing force in the vehicle longitudinal direction that the vehicle 100 receives from the towed vehicle 200 when the vehicle 100 is braked. Specifically, for example, the estimation unit 512 calculates the weight of the towed vehicle 200, the horizontal distance from the connection between the towed vehicle 200 and the vehicle 100 to the front wheel of the vehicle 100, and the horizontal distance from the connection to the rear wheel of the vehicle 100. The vertical load of each wheel is estimated based on the distance, the vertical distance from the connecting portion to the ground surface, the deceleration of the vehicle 100, and the like (details will be described later).

  The calculation unit 513 calculates the braking force of each wheel based on the vertical load of each wheel estimated by the estimation unit 512. Specifically, for example, the calculation unit 513 calculates the braking force of each wheel based on the vertical load of each wheel estimated by the estimation unit 512 so as to approach the ideal braking force distribution (details will be described later). .

  The braking control unit 514 controls braking of each wheel based on the braking force calculated by the calculation unit 513.

  Next, the processing contents of the estimation unit 512 and the calculation unit 513 will be described with reference to FIGS. 2 and 3 are side views schematically showing the vehicle 100 and the towed vehicle 200 of the first embodiment.

  The vehicle 100 includes a connecting portion 101. The front wheel FT is a general term for the front wheels FR and FL in FIG. The rear wheel RT is a general term for the rear wheels RR and RL in FIG. The tow vehicle center of gravity 102 is the center of gravity of the vehicle 100.

  The towed vehicle 200 includes a pair of wheels 201 and a connecting member 202. The towed vehicle center of gravity 203 is the center of gravity of the towed vehicle 200. The vehicle 100 and the towed vehicle 200 are swingably connected by connecting the connecting portion 101 and the connecting member 202. As a result, the towed vehicle 200 is towed along with the traveling of the vehicle 100, and at the time of steering, the vehicle 100 and the towed vehicle 200 assume a relative posture in which the vehicle 100 and the towed vehicle 200 bend in a top view, so that a course change and a turn can be performed.

  Further, in general, when the vehicle 100 is running while towing the towed vehicle 200, for example, when normal braking is performed by four wheels, the vehicle 100 assumes a front turning posture, the rear wheel RT skids, and A so-called “jack knife phenomenon” may occur in which the towing vehicle 100 and the towed vehicle 200 bend at the connecting portion 101. In the first embodiment, by applying an appropriate braking force to each wheel at the time of braking the vehicle 100, the possibility that an inconvenient phenomenon such as the jackknife phenomenon occurs is reduced.

  Here, the meaning of each symbol in FIGS. 2 and 3 will be described. The case where the vehicle 100 tow the towed vehicle 200 is referred to as “during towing”. The case where the vehicle 100 does not tow the towed vehicle 200 is referred to as “non-towing”.

  Ff is a force acting on the front wheel FT during braking. Fr is a force acting on the rear wheel RT during braking. α is the deceleration of the vehicle 100. Wtc is the weight of the vehicle 100. Wftc is the weight applied to the front wheels FT when the vehicle 100 is stationary. Wrtc is the weight applied to the rear wheel RT when the vehicle 100 is stationary.

  Htc is a vertical distance from the road surface R to the center of gravity of the towing vehicle 102. Lftc is a horizontal distance from the front wheel FT to the tow vehicle center of gravity 102. Lrtc is a horizontal distance from the rear wheel RT to the tow vehicle center of gravity 102.

  Wtr is the weight of the towed vehicle 200. Lftch is a horizontal distance from the front wheel FT to the connecting portion 101. Lrtch is a horizontal distance from the rear wheel RT to the connecting portion 101. Ltrh is a horizontal distance from the wheel 201 of the towed vehicle 200 to the connecting portion 101.

  Note that, among the information of each symbol, for example, information other than the information on the weight is known in advance, and is stored in the storage unit 520. The information on the weight is specified by, for example, actual measurement or estimation (details will be described later).

First, the simultaneous lock points when the front and rear wheels of the vehicle 100 are locked at the same time when the vehicle is not towed are as shown in the following expressions (1) and (2). G is the gravitational acceleration.
Ff = (α / g) ・ {Wftc + Wtc ・ Htc ・ α / g / (Lftc + Lrtc)} formula (1)
Fr = (α / g) ・ {Wrtc-Wtc ・ Htc ・ α / g / (Lftc + Lrtc)} ・ ・ ・ Formula (2)

  Equations (1) and (2) can be derived by the following concept. First, in the vehicle 100, a part of the weight applied to the rear wheel RT moves to the front wheel FT due to the inertia force during braking, as compared with when the vehicle 100 is stationary or running at a constant speed. The weight of the vehicle 100 is assumed to be at one point of the center of gravity of the towing vehicle 102. Equations (1) and (2) can be derived based on an equation based on a moment around the ground point of the front wheel FT and an equation based on a moment around the ground point of the rear wheel RT during braking. For more information, see "Doctor Nakazawa's Brake Library", [online], Neo Street, Inc., [Search August 21, 2018], Internet <http://www.neostreet.co.jp/brake2/special /s1.html>], and further description is omitted here.

Further, during towing, the weight Wftcd (vertical load) applied to the front wheel FT in consideration of the force acting on the connecting portion 101 (the pressing force in the vehicle longitudinal direction) is calculated as follows. First, the balance of the moment around the contact point of the rear wheel RT of the vehicle 100 is expressed by the following equation (3).
Wftcd ・ (Lftc + Lrtc) -Wtc ・ Lrtc-Wtc ・ Htc ・ α / g- (Wtc + Wtr) ・ Hh ・ α / g-Whd ・ Lftch = 0
... Equation (3)

When Wftcd is calculated from this equation (3), the following equation (4) is obtained.
Wftcd = Wtc ・ Lrtc / (Lftc + Lrtc) + ｛Wtc ・ Htc + (Wtc + Wtr) ・ Hh｝ ・ α / g / (Lftc + Lrtc) +
Whd ・ Lftch / (Lftc + Lrtc) ・ ・ ・ Equation (4)

Here, since Wftc = Wtc · Lrtc / (Lftc + Lrtc), Wftcd is represented by Expression (5).
Wftcd = Wftc + ｛Wtc · Htc + (Wtc + Wtr) · Hh｝ · α / g / (Lftc + Lrtc) + Whd · Lftch / (Lftc + Lrtc) ・ ・ ・ Equation (5)

Similarly, the weight Wrtcd (vertical load) applied to the rear wheel RT in consideration of the force acting on the connecting portion 101 (the pressing force in the vehicle longitudinal direction) is calculated as follows. First, the balance of the moment around the contact point of the front wheel FT of the vehicle 100 is expressed by the following equation (6).
Wrtcd ・ (Lftc + Lrtc) -Wtc ・ Lftc + Wtc ・ Htc ・ α / g + (Wtc + Wtr) ・ Hh ・ α / g-Whd ・ Lftch = 0
... Equation (6)

When Wrtcd is calculated from the equation (6), the following equation (7) is obtained.
Wrtcd = Wtc ・ Lftc / (Lftc + Lrtc)-｛Wtc ・ Htc + (Wtc + Wtr) ・ Hh｝ ・ α / g / (Lftc + Lrtc) +
Whd ・ Lftch / (Lftc + Lrtc) ・ ・ ・ Equation (7)

Here, since Wrtc = Wtc · Lftc / (Lftc + Lrtc), Wrtcd is represented by Expression (8).
Wrtcd = Wrtc- {Wtc ・ Htc + (Wtc + Wtr) ・ Hh} ・ α / g / (Lftc + Lrtc) + Whd ・ Lftch / (Lftc + Lrtc) ・ ・ ・ Equation (8)

Whd in Expressions (5) and (8) is as shown in Expression (9) below.
Whd = (Wtr · Ltrw + (Wtr · Htr- (Wtc + Wtr) · Hh · α / g)) / Ltrh Expression (9)

  In other words, Expressions (3) to (9) can be derived by the following concept. The vehicle 100 receives a pressing force (Fh in FIG. 3) in the vehicle front-rear direction from the towed vehicle 200 in the case of braking during towing as compared with the case of braking when not towing. In consideration of this pressing force, Equations (3) to (9) can be derived based on the equation based on the moment around the ground point of the front wheel FT and the equation based on the moment around the ground point of the rear wheel RT. it can.

Since the simultaneous lock point is obtained by multiplying the vertical load of the wheel by (α / g), it is as shown in the following Expressions (10) and (11).
Ff = (α / g) ・ ｛Wftc + ｛Wtc ・ Htc + (Wtc + Wtr) ・ Hh｝ ・ α / g / (Lftc + Lrtc) +
Whd ・ Lftch / (Lftc + Lrtc)｝ ・ ・ ・ Equation (10)
Fr = (α / g) ・ ｛Wrtc- ｛Wtc ・ Htc + (Wtc + Wtr) ・ Hh｝ ・ α / g / (Lftc + Lrtc) +
Whd ・ Lftch / (Lftc + Lrtc)｝ ・ ・ ・ Formula (11)

  Here, FIG. 4 is a graph showing an ideal braking force distribution in the first embodiment. In the graph of FIG. 4, the vertical axis represents the rear wheel braking force, and the horizontal axis represents the front wheel braking force. The curve L1 is an ideal braking force distribution curve during non-traction (Equations (1) and (2)). A curve L2 is an ideal braking force distribution curve during non-traction (Equations (10) and (11)).

  In the case of braking during towing, the vehicle receives a pressing force (Fh in FIG. 3) in the vehicle front-rear direction from the towed vehicle 200. Therefore, as the overall braking force increases, the curve L2 is more controlled by the rear wheel than the curve L1. It can be seen that the ratio of the front wheel braking force to the power becomes larger. Further, it can be seen from the curve 2 that the front wheel braking force decreases from the middle as it moves to the right side of the graph.

  For example, the function of the braking control based on the curve L2 which is the ideal braking force distribution curve at the time of towing may be added to a conventional EBD (Electronic Brake force Distribution: electronically controlled braking force distribution control).

  Next, a control procedure by the ECU 50 of the first embodiment will be described with reference to FIG. FIG. 5 is a flowchart illustrating an example of a control procedure performed by the ECU 50 according to the first embodiment. 5 is executed when the vehicle 100 is braked.

  First, in step S1, the acquisition unit 511 acquires data (signal) from each of the sensors SE1 to SE9, the brake switch SW1, and the like.

  Next, in step S2, the processing unit 510 specifies the weight of the towed vehicle 200. The weight of the towed vehicle 200 may be specified by actual measurement or estimation. In the case of actual measurement, measured weight data of the towed vehicle 200 is stored in the storage unit 520 in advance. In the case of estimation, the weight of the towed vehicle 200 is calculated based on the driving force of the driving force generation device 11, the longitudinal acceleration of the vehicle 100 by the longitudinal acceleration sensor SE7, the weight data of the vehicle 100 stored in advance, and the like. Can be estimated.

  Next, in step S3, the processing unit 510 determines whether or not the towed vehicle 200 is in a towing state based on the weight of the towed vehicle 200 specified in step S2. If Yes, the process proceeds to step S4. If No, the process proceeds to step S4. Proceed to S8.

  In step S4, the estimating unit 512 estimates the pressing force (Fh in FIG. 3) acting on the connecting unit 101 in the vehicle longitudinal direction.

  Next, in step S5, the estimation unit 512 estimates the vertical load of each wheel of the vehicle 100 based on the pressing force estimated in step S4. Steps S4 and S5 can be specifically realized by calculating the above equations (10) and (11).

  Next, in step S6, the calculation unit 513 calculates the braking force of each wheel based on the vertical load of each wheel estimated in step S5. Specifically, the calculation unit 513 distributes the braking forces of the front and rear wheels based on the vertical load of each wheel so as to approach the ideal braking force distribution during towing (curve L2 in FIG. 4).

  Next, in step S7, the braking control unit 514 controls braking of each wheel based on the braking force of each wheel calculated in step S6. After step S7, the process ends.

  On the other hand, in step S8, the calculation unit 513 calculates a normal (non-traction) braking force. Next, in step S9, the braking control unit 514 controls braking of each wheel based on the braking force of each wheel calculated in step S8. After step S9, the process ends.

  As described above, according to the first embodiment, an appropriate braking force can be applied to each wheel when the vehicle 100 is braked. Specifically, even during towing, the vertical load of each wheel is estimated based on the pressing force in the vehicle longitudinal direction that the vehicle 100 receives from the towed vehicle 200 during braking, and based on the vertical load of each wheel. By calculating the braking force of each wheel and controlling the braking of each wheel based on the braking force of each wheel, the behavior of the vehicle 100 can be stabilized and the target deceleration can be easily realized. Further, it is possible to reduce a possibility that an undesired phenomenon such as the jack knife phenomenon occurs.

  It is not always necessary to distribute the braking force of the front and rear wheels strictly in accordance with the ideal braking force distribution during towing (curve L2 in FIG. 4). By distributing the braking force of the front and rear wheels so as to approach L2), the effect of stabilizing the behavior of the vehicle 100 and the like can be obtained.

(2nd Embodiment)
Next, a second embodiment will be described. Regarding the same items as in the first embodiment, the overlapping description will be omitted as appropriate. The second embodiment is different from the first embodiment in that the vehicle 100 and the towed vehicle 200 are not on a horizontal road surface but on a slope (hill). When the vehicle 100 is on a slope, the estimation unit 512 estimates the vertical load of each wheel based on the direction and degree of the slope of the slope. Hereinafter, a specific description will be given.

FIG. 6 is a side view schematically showing the vehicle 100 and the towed vehicle 200 on the slope R1 in the second embodiment. First, when the vehicle is not towed (when the vehicle 100 is alone on the slope R1), the simultaneous lock point is represented by the following formulas (21) and (22) in consideration of the gradient θ of the slope R1. It is on the street.
Ff = (α / g) ・ {Wftc ・ cosθ + (Wtc ・ sinθ + Wtc ・ α / g) ・ Htc / (Lftc + Lrtc)}
... Equation (21)
Fr = (α / g) ・ {Wrtc ・ cosθ- (Wtc ・ sinθ + Wtc ・ α / g) ・ Htc / (Lftc + Lrtc)}
... Equation (22)

Also, when the force acting on the connecting portion 101 is taken into account during towing, the weight Wftcd (vertical load) applied to the front wheel FT is as shown in Expression (23), and the weight Wrtcd (vertical load) applied to the rear wheel RT is expressed by Expression (24) It becomes as follows.
Wftcd = Wftc ・ cosθ + ｛(Wtc ・ sinθ + Wtc ・ α / g) ・ Htc +
(Wtr ・ sinθ + (Wtc + Wtr) ・ α / g) ・ Hh + Whd ・ Lftch｝ / (Lftc + Lrtc)｝ ・ ・ ・ Equation (23)
Wrtcd = Wrtc ・ cosθ + ｛-(Wtc ・ sinθ + Wtc ・ α / g) ・ Htc-
(Wtr ・ sinθ + (Wtc + Wtr) ・ α / g) ・ Hh + Whd ・ Lftch｝ / (Lftc + Lrtc)｝ ・ ・ ・ Equation (24)

Note that Whd in Expressions (23) and (24) is as shown in Expression (25) below.
Whd = (Wtr · cosθ · Ltrw + Wtr · sinθ · Htr + (Wtr · Htr− (Wtc + Wtr) · Hh · α / g)) / Ltrh ・ ・ ・ Equation (25)

Since the simultaneous lock point is obtained by multiplying the vertical load of the wheel by (α / g), the simultaneous lock point is as shown in the following equations (26) and (27).
Ff = (α / g) ・ ｛Wftc ・ cosθ + ｛(Wtc ・ sinθ + Wtc ・ α / g) ・ Htc + (Wtr ・ sinθ + (Wtc + Wtr) ・ α / g) ・ Hh + Whd ・ Lftch｝ / (Lftc + Lrtc)｝ Equation (26)
Fr = (α / g) ・ ｛Wrtc ・ cosθ + ｛-(Wtc ・ sinθ + Wtc ・ α / g) ・ Htc- (Wtr ・ sinθ + (Wtc + Wtr) ・ α / g) ・ Hh + Whd ・ Lftch ｝ / (Lftc + Lrtc)｝ ・ ・ ・ Equation (27)

  As described above, according to the second embodiment, when the vehicle 100 is on the sloping road surface R1, an appropriate braking force can be applied to each wheel when the vehicle 100 is braked in consideration of the gradient. .

  As described above, the embodiment of the present invention has been exemplified, but the above embodiment is merely an example, and is not intended to limit the scope of the invention. The above embodiments can be implemented in other various forms, and various omissions, replacements, combinations, and changes can be made without departing from the spirit of the invention. In addition, the specifications (structure, type, number, etc.) of each configuration, shape, and the like can be appropriately changed and implemented.

  For example, in addition to the pressing force in the front-rear direction of the vehicle (Fh in FIG. 3), the estimating unit 512 applies a vertical load (Fv in FIG. 3) from the towed vehicle 200 to the connecting portion 101 generated by the deceleration of the vehicle 100. , The vertical load of each wheel may be estimated. For example, as shown in FIGS. 2 and 3, in the towed vehicle 200, a static vertical direction added when the towed vehicle center of gravity 203 is located ahead of the wheel 201 (to the left in FIGS. 2 and 3). Considering the load and the dynamic vertical load (Fv in FIG. 3) due to the pitching moment from the towed vehicle 200 to the connecting portion 101 generated by the deceleration of the vehicle 100, the braking force distribution of each wheel is taken into account. Accuracy can be further improved. The static vertical load and the dynamic vertical load are the weight Wtr of the towed vehicle 200, ltrw which is the horizontal distance between the towed vehicle center of gravity 203 and the wheel 201 of the towed vehicle 200, the towed vehicle It can be calculated based on the height htr of the center of gravity 203 from the ground contact surface and Ltrh, which is the horizontal distance from the wheel 201 of the towed vehicle 200 to the connecting portion 101, and the like.

  In the above-described embodiment, the vehicle 100 is described as being a four-wheeled vehicle. However, the vehicle 100 is not limited to a four-wheeled vehicle, and may be applied to other vehicles such as a six-wheeled vehicle and an eight-wheeled vehicle. Can be applied.

  DESCRIPTION OF SYMBOLS 11 ... Driving force generation device, 12 ... Steering device, 13 ... Braking device, 50 ... ECU, 100 ... Vehicle, 101 ... Connection part, 102 ... Towing vehicle center of gravity, 200 ... Towed vehicle, 201 ... Wheel, 202 ... Connection member 203, a center of gravity of the towed vehicle, 510, a processing unit, 511, an acquisition unit, 512, an estimation unit, 513, a calculation unit, 514, a braking control unit, 520, a storage unit

Claims (6)

A vehicle brake control device mounted on a tow vehicle for towing a tow vehicle,
A calculating unit that calculates a braking force of each wheel of the tow vehicle based on a pressing force in a vehicle longitudinal direction that the tow vehicle receives from the tow vehicle during braking of the tow vehicle,
A braking control unit that controls braking of each of the wheels based on the braking force,
A vehicle braking control device comprising: An estimating unit that estimates a vertical load of each of the wheels based on the pressing force, further comprising:
The vehicle brake control device according to claim 1, wherein the calculation unit calculates a braking force of each of the wheels based on the vertical load of each of the wheels.   The estimating unit is a weight of the towed vehicle, a horizontal distance from a connection between the towed vehicle and the towed vehicle to a front wheel of the towed vehicle, a horizontal distance from the connection to the rear wheel of the towed vehicle, The vehicle braking control device according to claim 2, wherein the vertical load of each of the wheels is estimated based on a vertical distance from a connection portion to a ground contact surface and a deceleration of the towing vehicle. When the towing vehicle is on a slope,
4. The vehicle braking control device according to claim 2, wherein the estimating unit estimates a vertical load of each of the wheels based on a direction and a degree of a slope of the slope. 5.   The estimating unit estimates the vertical load of each of the wheels based on a vertical load from the towed vehicle to the connecting unit generated by deceleration of the tow vehicle, in addition to the pressing force in the vehicle front-rear direction. The vehicle brake control device according to claim 3, wherein   The method according to claim 2, wherein the calculation unit calculates a braking force of each of the wheels based on the vertical load of each of the wheels such that an ideal braking force distribution is obtained. 7. Vehicle braking control device.

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