Vehicular control device

Abstract

To restrain a brake squeak.SOLUTION: A vehicular control device (50) has a target brake driving force setting part (513) setting target driving force based on a difference between request brake force and target brake force by setting target brake force based on a prescribed target brake force gradient when established a prescribed condition in a state of not imparting brake force to a wheel (such as FR) and a brake drive control part (514) performing brake drive control based on its target brake force and target driving force.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a control device for a vehicle. [Background technology]

[0002] Patent Document 1 discloses a vehicle brake control device that suppresses brake squeal in the front wheels by maintaining the front wheel hydraulic pressure at 0 and increasing only the rear wheel hydraulic pressure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-157431 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the vehicle brake control device disclosed in Patent Document 1, when the gradient of the required braking force is small, even if only the rear wheel hydraulic pressure is increased, it may not be possible to suppress brake squeal of the front wheels. One aspect of the present disclosure is directed to suppressing brake squeal. [Means for solving the problem]

[0005] In order to solve the above problems, a vehicle control device according to one embodiment of the present disclosure is a vehicle control device applied to a vehicle having a braking device that controls an actuator that generates a braking force on the wheel by contacting a friction member with the wheel of the vehicle or a rotating member that rotates together with the wheel, and a drive device that applies a driving force to the vehicle, and is equipped with a target braking / driving force setting unit that sets a target braking force to increase the braking force at a predetermined target braking force increase gradient when a squeal suppression control execution condition is met, including the receipt of a braking request when no braking force is applied to the wheel, and sets a target driving force based on the difference between the target braking force and the required braking force when the target braking force is greater than a required braking force, which is the braking force required of the vehicle, and a braking / driving control unit that performs braking / driving control based on the target braking force set by the target braking / driving force setting unit and the target driving force. Effect of the Invention

[0006] According to one aspect of the present disclosure, brake squeal can be suppressed. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing a schematic configuration of a vehicle equipped with a vehicle control device according to an embodiment of the present disclosure. [Diagram 2] 5A and 5B are diagrams for explaining the processing of a target braking / driving force setting unit. [Diagram 3] 5 is a flowchart showing a flow of processing by a target braking / driving force setting unit and a braking / driving force control unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Fig. 1 is a diagram showing a schematic configuration of a vehicle equipped with a vehicle control device according to an embodiment of the present disclosure. The vehicle control device 50 shown in Fig. 1 is, for example, an ECU (Electronic Control Unit). As shown in Fig. 1, the vehicle is provided with a driving force generating device 11 for driving the vehicle, a steering device 12 for steering the front wheels FR and FL as steered wheels, and a braking device 13 for applying a braking force to each of the wheels FL, FR, RL and RR (hereinafter, the reference numerals may be omitted and simply referred to as "wheels").

[0009] The driving force generating device 11 is an example of a driving device. The driving force generating device 11 includes an engine 21 that generates driving force based on the amount of operation of an accelerator pedal 20 by the vehicle driver, i.e., the accelerator opening, and an automatic transmission 22 that is connected to the output shaft of the engine 21. The driving force generating device 11 includes 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 a differential gear 23, and distributed from the differential gear 23 to front wheels FR and FL, which are drive wheels.

[0010] The vehicle is provided with a shift device 25 that is operated by the driver. When the range of the shift device 25 is the forward range, the automatic transmission 22 outputs a driving force in a direction that moves the vehicle forward. On the other hand, when the range of the shift device 25 is the reverse range, the automatic transmission 22 outputs a driving force in a direction that moves the vehicle backward. Shift information such as whether the range is the forward range or the reverse range is transmitted from the shift device 25 to a vehicle control device 50 that controls the braking device 13.

[0011] Steering device 12 is provided with a steering shaft 31 to which steering wheel 30 steered by the driver is fixed, and a steering actuator 32 connected to steering shaft 31. Steering device 12 is also provided with a link mechanism 33 including a tie rod that can be moved in the left-right direction of the vehicle by steering actuator 32, and a link that steers front wheels FL and FR by movement of the tie rod. Steering device 12 is also provided with a steering angle sensor SE2 that outputs a detection signal corresponding to the steering angle of steering wheel 30 to vehicle control device 50. Steering angle sensor SE2 outputs a detection signal such that the steering angle is a positive value when the vehicle is turned right, and outputs a detection signal such that the steering angle is a negative value when the vehicle is turned left.

[0012] The braking device 13 is provided with a hydraulic pressure generating device 41 that generates a brake hydraulic pressure according to the operating force of the brake pedal 40 by the driver, and a brake actuator 43. The brake actuator 43 is connected to brake devices 42a, 42b, 42c, and 42d that are provided for the wheels FR, FL, RR, and RL, respectively. The braking device 13 is provided with a brake switch SW1 that outputs a detection signal to the vehicle control device 50 according to the operating state (on or off) of the brake pedal 40 by the driver.

[0013] Brake actuator 43 is configured to apply braking force to each of wheels FR, FL, RR, and RL even when the driver does not operate brake pedal 40. For example, brake actuator 43 includes a differential pressure control valve for generating a differential pressure between the brake fluid pressure on the hydraulic pressure generating device 41 side and the brake fluid pressure in the wheel cylinders provided in brake devices 42a, 42b, 42c, and 42d, and an electric pump for supplying brake fluid into the wheel cylinders. Brake actuator 43 may be provided with various valves for individually adjusting the brake fluid pressure in each wheel cylinder.

[0014] The vehicle control device 50 is electrically connected to the accelerator opening sensor SE1, the steering angle sensor SE2, the brake switch SW1, and wheel speed sensors SE3, SE4, SE5, and SE6 for detecting the wheel speeds of the wheels FR, FL, RR, and RL. The vehicle control device 50 is also electrically connected to a longitudinal acceleration sensor SE7 for detecting the acceleration in the longitudinal direction of the vehicle (hereinafter referred to as "longitudinal acceleration"), a lateral acceleration sensor SE8 for detecting the acceleration in the lateral direction (vehicle width direction) of the vehicle (hereinafter referred to as "lateral acceleration"), and a yaw rate sensor SE9 for detecting the yaw rate of the vehicle.

[0015] When the road surface on which the vehicle is traveling is a horizontal road, the longitudinal acceleration sensor SE7 outputs a detection signal that indicates a positive longitudinal acceleration value when the vehicle accelerates, and outputs a detection signal that indicates a negative longitudinal acceleration value when the vehicle decelerates. In addition, when the vehicle stops on a downhill road, the center of gravity of the vehicle moves forward, so that the longitudinal acceleration calculated based on the detection signal from the longitudinal acceleration sensor SE7 becomes a negative value.

[0016] Further, the lateral acceleration sensor SE8 and the yaw rate sensor SE9 detect signals such that when the vehicle turns to the right, the lateral acceleration and the yaw rate of the vehicle have positive values, whereas when the vehicle turns to the left, the lateral acceleration and the yaw rate of the vehicle have negative values. The numbers are output respectively.

[0017] The vehicle control device 50 of this embodiment is applied to a vehicle in which actuators are provided on a plurality of wheels, which generate a braking force on the wheels by bringing a friction member into contact with the vehicle wheels or a rotating member that rotates together with the wheels. More specifically, the vehicle control device 50 of this embodiment is applied to a vehicle (e.g., a four-wheeled vehicle) in which a friction member (e.g., a brake pad) that is pressed by a braking hydraulic pressure against a rotating member (e.g., a brake disc) that rotates together with the wheels is provided on each of the plurality of wheels.

[0018] The squeal that occurs during braking in a vehicle is caused by vibrations resulting from friction between, for example, the brake pads and the brake discs. Specifically, when the brake pads come into contact with the brake discs, micro-vibrations are generated due to uneven contact, which causes self-excited vibrations, which are then transmitted to surrounding components, causing squeal. In addition, there are several conceivable regions (ranges) of brake fluid pressure in which squealing is likely to occur, such as a low pressure region including zero fluid pressure and a medium pressure region where fluid pressure is moderate.

[0019] The vehicle control device 50 may be incorporated in an ECU of any system mounted on the vehicle, or may be an independent ECU. The vehicle control device 50 may have a CPU (Central Processing Unit), a controller, a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, etc., which are not shown. The vehicle control device 50 executes processing according to installed and loaded programs, and realizes each function. In the following description, it is assumed that the vehicle control device 50 performs the same braking / driving control on the wheels FR, FL, RR, and RL.

[0020] The vehicle control device 50 includes a processing unit 510 and a storage unit 520. The processing unit 510 includes, as functional units, an acquisition unit 511, a driving control unit 512, a target braking / driving force setting unit 513, and a braking / driving control unit 514. That is, the vehicle control device 50 can realize each functional unit by executing processing according to a program. In addition, the storage unit 520 stores programs and data used in the arithmetic processing of each functional unit, data resulting from the arithmetic processing, and the like. Note that at least a part of each functional unit may be realized by hardware.

[0021] The acquisition unit 511 acquires data (signals) from the sensors SE1-SE9, the brake switch SW1, etc. Obtain the ID number. The driving control unit 512 controls the driving of the vehicle by outputting an instruction signal to the driving force generating device 11, for example.

[0022] Target braking / driving force setting unit 513 sets a target braking force and a target driving force for the vehicle, as will be described later. Braking / driving control unit 514 performs braking / driving control based on the target braking force and target driving force set by target braking / driving force setting unit 513. Braking / driving control unit 514 controls braking device 13 based on the target braking force set by target braking / driving force setting unit 513, and applies braking force to the vehicle. Braking / driving control unit 514 also controls driving force generation device 11 based on the target driving force set by target braking / driving force setting unit 513, and applies driving force to the vehicle.

[0023] Fig. 2 is a diagram for explaining the processing of the target braking / driving force setting unit. Fig. 2(a) shows the required deceleration of the vehicle. Fig. 2(b) shows the brake fluid pressures at the wheels FR, FL, RR and RL. Fig. 2(c) shows the driving force of the vehicle. When the driver depresses the brake pedal 40, the required deceleration of the vehicle gradually increases, as shown in FIG. 2(a).

[0024] Brake squeal is likely to occur while the brake fluid pressure in each of the wheels FR, FL, RR, and RL is in a low pressure region below a predetermined threshold Pth shown in FIG. 2B. The target braking / driving force setting unit 513 executes squeal suppression control when a squeal suppression control execution condition is satisfied in which a braking request is received in a state in which no braking force is applied to the vehicle. The target braking / driving force setting unit 513 sets a target braking force so that the brake fluid pressure in each of the wheels FR, FL, RR, and RL quickly exceeds the predetermined threshold Pth when a squeal suppression control execution condition is satisfied in which a braking request is received in a state in which no braking force is applied to the vehicle. The predetermined threshold Pth is, for example, 0.5 MPa. The target braking / driving force setting unit 513 sets a target braking force based on a target braking force gradient so as to increase the braking force at a predetermined target braking force increase gradient. The target braking force gradient is set based on, for example, a required deceleration and a temperature of the brake pad. Furthermore, the target braking / driving force setting unit 513 further sets the target driving force when the squeal suppression control execution condition is met in which a braking request is received while no braking force is being applied to the vehicle. The squeal suppression control execution condition may include, for example, that the gradient of the requested braking force is smaller than the gradient of the target braking force. The squeal suppression control execution condition may include, for example, that the operation amount of the accelerator pedal 20 is zero, that the brake fluid pressures in the wheels FR, FL, RR, and RL are equal to or lower than a predetermined threshold value Pth, and that the traveling speed is lower than a predetermined speed.

[0025] The target braking / driving force setting unit 513 acquires the gradient of the required braking force and the gradient of the target braking force when no braking force is applied to the vehicle. The gradient of the required braking force can be calculated from the gradient of the required deceleration, for example.

[0026] As the target driving force setting unit 513 sets the target driving force, the braking / driving control unit 514 controls the driving force generating device 11 to generate a driving force for the vehicle as shown in FIG. 2(c). The value of the target driving force is calculated based on the difference between the required braking force and the target braking force. In order to make the braking force of the vehicle reach the required braking force, the braking / driving control unit 514 increases the brake fluid pressure in each of the wheels FR, FL, RR, and RL by the amount of the driving force generated in the vehicle. As a result, the brake fluid pressure in each of the wheels FR, FL, RR, and RL exceeds the predetermined threshold value Pth more quickly than if the target driving value was not set.

[0027] When the target braking force becomes larger than a predetermined threshold, the target braking force setting unit 513 reduces the target driving force. In (b) and (c) of Fig. 2, the target driving force is reduced during the period from timing T1 to T2. The target braking force setting unit 513 sets the target braking force based on the required braking force and the target driving force during the period in which the target driving force is being reduced. The target braking force is gradually reduced to 0, while the target braking force is set based on the required braking force and the target driving force.

[0028] 3 is a flowchart showing the flow of processing by the target braking / driving force setting unit and the braking / driving control unit. The series of processing shown in FIG.

[0029] In S100, the processing unit 510 of the vehicle control device 50 functions as a target braking / driving force setting unit 513 and determines whether or not the squeal suppression control execution condition for receiving a braking request is satisfied when no braking force is applied to the vehicle. When no braking force is applied to the vehicle and the squeal suppression control execution condition is satisfied (S100: YES), the processing unit 510 of the vehicle control device 50 sets a target braking force and a target driving force (S200). In S200, the processing unit 510 of the vehicle control device 50 sets a target braking value based on a predetermined target braking force gradient, and sets a target driving force based on the difference between the required braking force and the target braking force. On the other hand, when the squeal suppression control execution condition is not satisfied (S100: NO), the processing unit 510 of the vehicle control device 50 sets the target braking force to be the required braking force and executes normal braking control (S300). After that, the processing unit 510 of the vehicle control device 50 ends the processing of the current cycle and starts the processing of the next cycle.

[0030] In S400, the processing unit 510 of the vehicle control device 50 functions as the braking / driving control unit 514 and performs braking / driving control based on the target braking force and target driving force set in S200. After that, the processing unit 510 of the vehicle control device 50 ends the processing of the current cycle and starts the processing of the next cycle.

[0031] [Modifications] In the above embodiment, the target braking / driving force setting unit 513 reduces the target driving force when the target braking force becomes greater than a predetermined threshold. However, the timing at which the target driving force setting value starts to be reduced is not limited to the timing at which the target braking force becomes greater than the predetermined threshold. For example, the target driving force setting value may start to be reduced when the brake fluid pressure at each of the wheels FR, FL, RR, and RL becomes equal to or greater than a predetermined threshold Pth, when the braking force applied to the vehicle becomes equal to or greater than a predetermined threshold, or when the required braking force becomes equal to or greater than a predetermined threshold.

[0032] In the above embodiment, the vehicle control device 50 performs the same braking / driving control for the wheels FR, FL, RR, and RL. However, the vehicle control device 50 may perform braking / driving control for each wheel individually and adjust the braking force individually. For example, the brake fluid pressure of the rear wheels RR and RL may be increased before the brake fluid pressure of the front wheels FR and FL. In this case, the squeal suppression control execution condition may include the timing to increase the brake fluid pressure of the front wheels FR and FL. In the above embodiment, an example of a vehicle control device that generates hydraulic pressure has been described. However, the present invention may be realized as a vehicle control device that does not generate hydraulic pressure. For example, the present invention may be applied to a vehicle in which a brake device is provided on a plurality of wheels, the brake device bringing a friction member into contact with a rotating member by the driving force of an electric motor to generate a braking force on the wheels.

[0033] 〔summary〕 A vehicle control device according to one aspect of the present disclosure is a vehicle control device applied to a vehicle having a braking device that controls an actuator that generates a braking force on the wheel by contacting a friction member with the wheel of the vehicle or a rotating member that rotates together with the wheel, and a drive device that applies a driving force to the vehicle, and is equipped with a target braking / driving force setting unit that sets a target braking force to increase the braking force based on a predetermined target braking force increase gradient when a squeal suppression control execution condition is met, including the receipt of a braking request when no braking force is applied to the wheel, and sets a target driving force based on the difference between the target braking force and the required braking force when the target braking force is greater than a required braking force, which is the braking force required of the vehicle, and a braking / driving control unit that performs braking / driving control based on the target braking force set by the target braking / driving force setting unit and the target driving force. In the present disclosure, the target braking force is set based on a predetermined braking force gradient, and the target driving force is set based on the difference between the target braking force and the required braking force. As a result, even if the increase gradient of the required braking force is smaller than the increase gradient of the target braking force, the driving force can be generated to increase the braking force at the target braking force gradient. As a result, brake squeal can be suppressed. In the above embodiment, brake squeal of the front and rear wheels of the vehicle can be suppressed.

[0034] In the vehicle control device according to one aspect of the present disclosure, the condition for executing the squeal suppression control includes a condition that a gradient of the required braking force is smaller than a gradient of the target braking force. When the gradient of the required braking force is larger than the gradient of the target braking force, there is no need to generate a driving force. Therefore, by not executing the squeal suppression control when the gradient of the required braking force is sufficiently large, it is possible to suppress energy consumption due to the generation of the driving force.

[0035] In a vehicle control device according to one embodiment of the present disclosure, when the braking force applied to the vehicle or the target braking force is greater than a predetermined threshold, the braking / driving force setting unit sets the target braking force based on the required braking force and the target driving force while reducing the target driving force. When the brake fluid pressure exceeds the low pressure region and the braking force exceeds the low braking force band, brake squeal is unlikely to occur regardless of the braking force. Therefore, by releasing the driving force when the braking force band that is the target of squeal suppression is exceeded, energy consumption due to the generation of driving force can be suppressed.

[0036] In the vehicle control device according to one aspect of the present disclosure, the predetermined condition for executing noise suppression control includes an accelerator depression amount of the vehicle being zero. In the vehicle control device according to one aspect of the present disclosure, the target braking / driving force setting unit sets the same target braking force and target driving force for the front wheels and rear wheels of the vehicle. In a vehicle control device according to one embodiment of the present disclosure, the target braking / driving force setting unit sets the target braking force based on the required braking force and the target driving force, while gradually reducing the target driving force to zero from the point at which the target braking force exceeds a predetermined threshold value. In the above embodiment, brake squeal of the front and rear wheels of the vehicle can be suppressed.

[0037] [Additional Notes] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. [Explanation of symbols]

[0038] 11 Driving force generating device 13 Braking device 20 Accelerator pedal 40 Brake pedal 41 Hydraulic pressure generator 42a Brake device 43 Brake Actuator 50 Vehicle control device 510 Processing section 513 Target braking / driving force setting unit 514 Braking / driving control unit FR, FL, RR, RL wheels

Claims

1. A vehicle control device that is applied to a vehicle having a braking device that controls an actuator that generates a braking force on a wheel of the vehicle by bringing a friction member into contact with a wheel of the vehicle or a rotating member that rotates together with the wheel, and a drive device that applies a drive force to the vehicle, a target braking / driving force setting unit that, when a squeal suppression control execution condition is satisfied, including the receipt of a braking request in a state where braking force is not being applied to the wheels, sets a target braking force so as to increase the braking force at a predetermined target braking force increase gradient, and, when the target braking force is greater than a required braking force, which is a braking force required for the vehicle, sets a target driving force based on a difference between the target braking force and the required braking force; a braking / driving control unit that performs braking / driving control based on the target braking force and the target driving force set by the target braking / driving force setting unit; A vehicle control device comprising:

2. 2. The vehicle control device according to claim 1, wherein the condition for executing the squeal suppression control includes a condition that a gradient of the required braking force is smaller than a gradient of the target braking force.

3. 2. The vehicle control device according to claim 1, wherein the target braking / driving force setting unit, in noise suppression control, increases the target braking force at the target braking force increase gradient, and then, when the braking force applied to the vehicle is greater than a predetermined threshold value, sets the target braking force based on the required braking force and the target driving force while reducing the target driving force.

Images