Brake system

Abstract

The braking system can improve the driving stability when the parking brake acts, is provided with the service brake capable of generating first braking force to the vehicle and the parking brake capable of generating second braking force to the vehicle, and is provided with a hardware processor. The hardware processor controls the first braking force according to a body speed of the vehicle and controls the second braking force according to the body speed.

Description

Technical Field

[0001] This disclosure relates to a braking system. Background Technology

[0002] Vehicles are equipped with service brakes for deceleration and stopping, and parking brakes for use when parked. Generally, service brakes are activated by fluid pressure (e.g., air pressure). Parking brakes, on the other hand, are activated by releasing fluid pressure, which allows the force of springs or similar components to act. It should be noted that in the following description, service brakes will also be referred to as "service brakes".

[0003] In addition, the vehicle is equipped with an Antilock Braking System (ABS), which automatically and repeatedly releases and engages the brakes to restore wheel grip and maintain vehicle stability when the wheels lock up during emergency braking, even if the driver continues to press the brake pedal.

[0004] For example, Patent Document 1 discloses a braking system that includes an electric parking brake, which can supply braking torque to the wheels by activating the electric parking brake to replace the service brake when the service brake fails or deteriorates.

[0005] Additionally, for example, Patent Document 2 discloses a braking system that, even in the event of an electronic malfunction in the regular brake, can perform a braking operation based on a driver's request via the parking brake.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2016-68940

[0009] Patent Document 2: German Patent Application Publication No. 102014006615 Summary of the Invention

[0010] The problem the invention aims to solve

[0011] However, the braking system described in Patent Document 1 has the following problem: if a malfunction occurs in the service brake, and the vehicle is slowed down and stopped by activating the parking brake, the driving stability when the parking brake is activated will be reduced because the system does not slow down and stop the vehicle based on the vehicle speed, which may cause the wheels to lock up.

[0012] The same problem exists in the braking system described in Patent Document 2. Since the braking system does not decelerate and stop the vehicle based on the vehicle speed, it may cause the wheels to lock up, thereby reducing driving stability when the parking brake is activated.

[0013] The purpose of this disclosure is to provide a braking system that can improve driving stability when the parking brake is engaged.

[0014] Solution to the problem

[0015] To achieve the above objectives, the braking system disclosed herein includes a service brake capable of generating a first braking force on a vehicle and a parking brake capable of generating a second braking force on the vehicle. The braking system is characterized by comprising:

[0016] The hardware processor controls the first braking force based on the vehicle's speed, and controls the second braking force based on the vehicle's speed.

[0017] Invention Effects

[0018] According to this disclosure, driving stability can be improved when the parking brake is activated. Attached Figure Description

[0019] Figure 1 It is a graph showing the relationship between longitudinal slip and longitudinal friction coefficient.

[0020] Figure 2 It is a graph showing the relationship between longitudinal slip and the coefficient of friction in the lateral direction.

[0021] Figure 3 This is a block diagram illustrating an example of a braking system that functionally represents an embodiment of the present disclosure.

[0022] Figure 4A This is a diagram schematically illustrating an example of a braking system during driving according to an embodiment of the present disclosure.

[0023] Figure 4B This is a schematic diagram illustrating an example of a braking system when the service brake of an embodiment of the present disclosure is activated.

[0024] Figure 4C This is a schematic diagram illustrating an example of a braking system when the parking brake of an embodiment of the present disclosure is activated.

[0025] Figure 5 This is a block diagram illustrating an example of an FF control device according to an embodiment of the present disclosure.

[0026] Figure 6 This is a diagram schematically illustrating an example of a parking brake according to an embodiment of the present disclosure.

[0027] Figure 7 This is a block diagram that functionally represents a variation of the braking system according to an embodiment of the present disclosure.

[0028] Explanation of reference numerals in the attached figures

[0029] BC: Brake chamber;

[0030] BC / wP: Composite brake chamber;

[0031] BD: Brake disc;

[0032] BP: Brake pad;

[0033] BW: Back wall;

[0034] CS: Shell;

[0035] EPS: Electric parking brake switch;

[0036] FBM: Foot Brake Module;

[0037] FW: Front wall;

[0038] HCV: Manual control valve;

[0039] LD: Rod;

[0040] MPV: Multi-circuit protection valve;

[0041] PBC: Parking Brake Chamber;

[0042] PBCW: Parking brake chamber wall;

[0043] PCM: Pressure Control Module;

[0044] PW: next door;

[0045] RV: Relay valve;

[0046] SBC: Service brake chamber;

[0047] SBCW: Service brake chamber wall;

[0048] SPR1: First spring;

[0049] SPR2: Second spring;

[0050] TNK: can;

[0051] 100: Braking system;

[0052] 100P: Parking brake;

[0053] 100S: Service brake;

[0054] 110: Control unit. Detailed Implementation

[0055] The embodiments of this disclosure will now be described with reference to the accompanying drawings.

[0056] Figure 1 It is a graph showing the relationship between longitudinal slip and longitudinal braking friction coefficient for each of multiple sideslip angles. Figure 1 The vertical axis represents the tire (wheel) braking friction coefficient μ, and the horizontal axis represents the slip ratio (the percentage of the difference between vehicle speed and wheel speed divided by vehicle speed %). The sideslip angle is the angle between the direction the tire is facing and the direction the tire is traveling. Additionally, in Figure 1 In the diagram, the relationship between the two is represented by a solid line when the sideslip angle β (=0), by a single-dot dashed line when the sideslip angle β (=0.1), by a dotted line when the sideslip angle β (=0.2), and by a dashed line when the sideslip angle β (=0.3).

[0057] like Figure 1 As shown, in each of the multiple sideslip angles β, the longitudinal grip of the tire reaches its maximum when the tire slips slightly in the longitudinal direction (with a slip ratio between 10% and 20%), and the grip remains high for a considerable period of time even with further slip.

[0058] Figure 2 It is a graph showing the relationship between longitudinal slip and lateral braking friction coefficient for each of multiple sideslip angles. Figure 2 The vertical axis represents the tire's lateral braking friction coefficient μ, and the horizontal axis represents the slip ratio (%). Additionally, in Figure 2 In the figure, the relationship between the two is represented by a single-dot dashed line when the sideslip angle β (=0.1), by a dotted line when the sideslip angle β (=0.2), and by a dashed line when the sideslip angle β (=0.3).

[0059] like Figure 2 As shown, in each of the multiple sideslip angles β, the tire's lateral grip reaches its maximum when it is not slipping longitudinally, and drops sharply when it begins to slip longitudinally.

[0060] If the braking force of the brakes exceeds the grip of the tires, the tires will lock up and slip, making it difficult to maintain vehicle stability. The service brakes are equipped with ABS (Anti-lock Braking System), which controls the braking force based on the slip ratio when the service brakes are engaged. ABS can adjust the braking force to keep the slip ratio within the range of 10% to 20%, thus maintaining vehicle stability. On the other hand, conventional parking brakes are primarily used to suppress movement of the vehicle while parked. Parking brakes have a parking brake chamber. The parking brake is activated by adjusting the pressure in the parking brake chamber to a specified pressure, and released by adjusting the pressure in the parking brake chamber to atmospheric pressure.

[0061] When slowing down or stopping a vehicle, the parking brake is sometimes used instead of the service brake. However, conventional parking brakes lacked ABS (Anti-lock Braking System) to control braking force based on the slip ratio. This meant that, because the braking force could not be controlled according to the slip ratio, it was difficult to maintain vehicle stability when the parking brake was engaged.

[0062] Figure 3 This is a block diagram illustrating an example of a braking system functionally representing an embodiment of the present disclosure. Figure 3 In the braking system 100 shown, the pneumatic circuit is represented by solid lines, and the signal circuit is represented by dashed lines. Additionally, Figure 3 The control unit 110 shown does not represent a structure based on hardware (devices), but rather a structure based on functions. Therefore, functional blocks can be installed in a single device or separately in multiple devices. Data transmission and reception between functional blocks can also be performed via any unit such as a data bus or a controller area network (CAN bus).

[0063] The braking system 100 includes braking systems for the front wheels and rear wheels respectively. The front wheel braking system includes a service brake 100S. The rear wheel braking system includes a service brake 100S and a parking brake 100P. The following description will primarily focus on the rear wheel braking system, while the description of the front wheel braking system will be omitted. Furthermore, the rear wheel braking system is sometimes simply referred to as a "braking system," and sometimes described as "braking system 100." Additionally, the rear wheels are sometimes referred to as "wheels."

[0064] The service brake 100S includes: a tank; a foot brake modulator (FBM); a pressure control module (PCM); and multiple brake chambers with parking brakes (BC / wP). It should be noted that the number of brake chambers with parking brakes (BC / wP) corresponds to the number of wheels supplied with air pressure from the parking brake circuit. The multiple brake chambers with parking brakes (BC / wP) have identical structures and are shared by the service brake 100S and the parking brake 100P. Figure 3 The example is represented by one of the multiple composite brake chambers BC / wP.

[0065] Compressed air (hereinafter referred to as "air") is stored in the tank TNK. The foot brake module FBM is, for example, a brake pedal located under the driver's foot and operated by the driver. The pressure control module PCM controls the pressure of the air flowing into the tank TNK based on the amount of brake pedal depressor input. The pressure-controlled air is then supplied to the service brake chamber SBC of the compound brake chamber BC / wP. This activates the service brake 100S. Details regarding the compound brake chamber BC / wP will be described later.

[0066] The parking brake 100P includes: a multi-protection valve (MPV); a hand control valve (HCV); dual check valves; a relay valve; and multiple compound brake chambers BC / wP. It should be noted that, as described above, the multiple compound brake chambers BC / wP have the same structure and are shared by the service brake 100S and the parking brake 100P. In the following description, the chamber of the service brake 100S will be referred to as the "service brake chamber" and described as "service brake chamber SBC". Furthermore, the chamber of the parking brake 100P will be referred to as the "parking brake chamber" and described as "parking brake chamber PBC".

[0067] The multi-circuit protection valve (MPV) supplies air pressure from the tank TNK into the hand control valve HCV. The hand control valve HCV, located next to the driver's seat, is operated by the driver to control the parking brake control air pressure circuit from the MPV to the dual check valve. The dual check valve is a valve with a high-priority function, supplying the higher of the air pressure from the foot brake module FBM to the relay valve RV and the air pressure supplied from the hand control valve HCV to the relay valve. The relay valve RV is used to amplify the air flow. Based on the command pressure supplied from the dual check valve, the relay valve RV amplifies the flow, supplying air into and venting air from the parking brake chamber PBC to the outside. When the parking brake 100P is not operated (e.g., while driving), air is supplied to the parking brake chamber PBC through the relay valve RV, maintaining the parking brake chamber PBC at high pressure. When the parking brake 100P is operated, air is discharged from the parking brake chamber PBC to the outside via the relay valve RV, thereby reducing the pressure in the parking brake chamber PBC. The control of the relay valve RV is executed by the control unit 110.

[0068] The braking system 100 is a system that independently controls the braking force applied to each of the multiple wheels. In the following description, the control of braking force applied to one wheel will be used as an example. Figure 4A This is a diagram schematically illustrating an example of a braking system during driving according to an embodiment of the present disclosure. Figure 4B This is a schematic diagram illustrating an example of a braking system when the service brake of an embodiment of the present disclosure is activated. Figure 4C This is a schematic diagram illustrating an example of a braking system when the parking brake of an embodiment of the present disclosure is activated. Figures 4A-4C The diagram shows the braking system for the wheels, used for deceleration and stopping. Figures 4A-4C In the diagram, the side closer to the brake disc BD of the wheel is called the front side, while the side farther from the brake disc BD of the wheel is called the back side.

[0069] like Figure 4A As shown, the braking system 100 includes: a housing CS; a service brake chamber SBC; a parking brake chamber PBC; brake pads BP; a lever LD; a first spring SPR1; and a second spring SPR2.

[0070] The housing CS has a front wall FW on the front side, a rear wall BW on the rear side, and a peripheral wall SW that surrounds the interior of the housing CS from the outside. The service brake chamber SBC is located on the front side inside the housing CS. The parking brake chamber PBC is located on the rear side inside the housing CS.

[0071] The housing CS and the service brake chamber SBC are separated by the service brake chamber wall SBCW. The housing CS and the parking brake chamber PBC are separated by the parking brake chamber wall PBCW. The service brake chamber SBC and the parking brake chamber PBC are separated by a partition wall PW. For the service brake chamber SBC, air (AirSB) can be supplied to and discharged from it. For the parking brake chamber PBC, air (AirPB) can be supplied to and discharged from it.

[0072] The first spring SPR1 is configured in a compressed state between the front wall FW and the service brake chamber wall SBCW. The second spring SPR2 is configured in a compressed state between the rear wall BW and the parking brake chamber wall PBCW.

[0073] One end of the lever LD is connected to the service brake chamber wall SBCW. The middle portion of the lever LD passes through the front wall FW and is configured to reciprocate between the front and rear sides of the front wall FW. The other end of the lever LD is connected to the brake pad BP.

[0074] The pressure control module PCM controls the pedal operation of the foot brake module FBM to supply air to or exhaust air from the compound brake chamber BC / wP, which is the chamber used for wheel braking.

[0075] (When the service brake is released, or while driving)

[0076] Next, refer to Figure 4A Explain the operation of the service brake 100S during driving.

[0077] During driving, air is expelled from the service brake chamber SBC, thus reducing the pressure in the service brake chamber SBC. Consequently, the service brake chamber wall SBCW retracts from the front side to the back side under the restoring force of the first spring SPR1. Simultaneously, the brake pad BP moves from the front side to the back side via the rod LD, separating the brake pad BP from the brake disc BD of the wheel. It should be noted that the parking brake chamber PBC remains under high pressure during driving.

[0078] (When the service brake is activated)

[0079] Next, refer to Figure 4B Explain the situation when the service brake is activated.

[0080] When the service brake 100S is activated, air is supplied to the service brake chamber SBC, increasing the pressure in the SBC. As a result, the service brake chamber wall SBCW bulges from the back side to the front side against the restoring force of the first spring SPR1. Simultaneously, the brake pad BP moves from the back side to the front side via the rod LD, pressing the brake pad BP against the brake disc BD of the wheel. This generates braking force on the wheel. It should be noted that the parking brake chamber PBC also remains under high pressure when the service brake 100S is activated.

[0081] It should be noted that, in order to maintain vehicle stability when the service brakes are engaged for 100 seconds, the vehicle has an anti-lock braking system (ABS). The ABS controls the braking force on the wheels by controlling the pressure of the service brake chambers (SBCs). It should be noted that the ABS corresponds to the "hardware processor" of this disclosure. Furthermore, the ABS independently controls the braking force on each of the multiple wheels.

[0082] (When the parking brake is engaged)

[0083] Next, refer to Figure 4C Explain the situation when the parking brake is activated.

[0084] When the parking brake 100P is applied, the control unit 110 controls the relay valve RV to discharge air from the parking brake chamber PBC. This reduces the pressure in the parking brake chamber PBC. It should be noted that when the parking brake 100P is applied, the pressure in the service brake chamber SBC is in a depressurized state. Consequently, the parking brake chamber wall PBCW displaces from the rear side to the front side under the restoring force of the second spring SPR2. Simultaneously, through the movement of the lever LD and the brake pad BP from the rear side to the front side, the brake pad BP is pressed against the brake disc BD of the wheel. This generates braking force on the wheel.

[0085] The braking system of this disclosure includes a feedforward control device that, in order to maintain vehicle stability when the parking brake is engaged, controls the braking force (second braking force) of the wheels by controlling the pressure of the parking brake chamber PBC. It should be noted that... Figure 3The control unit 110 shown has a feedforward control device. The control unit 110 (feedforward control device) corresponds to the "hardware processor" of this disclosure. In the following description, the feedforward control device is sometimes referred to as the "FF control device". Furthermore, the FF control device controls the relay valve RV to adjust the braking force of the wheels. The FF control device can control the pressure of the parking brake chamber PBC through feedforward control corresponding to the vehicle speed. And, the FF control device can control the pressure of the parking brake chamber PBC through feedforward control corresponding to the wheel speed.

[0086] Figure 5 This is a block diagram illustrating an example of an FF control device according to an embodiment of the present disclosure.

[0087] The FF control device includes a storage unit and a control unit. The storage unit is either a read-only memory (ROM) that stores the program of the computer implementing the FF control device, or a random access memory (RAM) that serves as the working area of ​​the control unit 110. Furthermore, it includes interfaces such as an analog-to-digital converter (AD converter), a digital-to-analog converter (DA converter), input / output ports (I / O ports), and a controller area network (CAN). It should be noted that the ROM can be a storage device such as a hard disk drive (HDD) or a solid-state drive (SSD) that stores the operating system (OS) or application programs and various information referenced when executing the application.

[0088] The control unit 110 is a processor such as a central processing unit (CPU) or a graphics processing unit (GPU) of the FF control device, and operates by executing a program stored in a memory unit in the following manner. It should be noted that the FF control device is not limited to being composed of a single device. For example, the FF control device may also be implemented using computing resources such as multiple processors or memory. In this case, the various units constituting the FF control device are implemented by at least one of multiple different processors executing the program.

[0089] like Figure 5 As shown, the FF control device has three elements A, B and C. The transfer function representing the input / output characteristics of element A is expressed by the following equation (1).

[0090] (1)

[0091] Where V is the vehicle speed, a is the road friction coefficient calculation coefficient, b is the road friction coefficient calculation coefficient, and Fz is the axle load.

[0092] The transfer function representing the input / output characteristics of component B is expressed by the following equation (2).

[0093] (2)

[0094] Where r is the diameter of the wheel, r D Where F is the effective radius of the brake disc, f is the friction coefficient of the brake pads, and F spr This refers to the spring force of the parking brake.

[0095] The transfer function representing the input / output characteristics of component C is expressed by the following equation (3).

[0096] (3)

[0097] Where d is the effective diameter of the brake chamber, E is the braking ratio, and η is the mechanical efficiency.

[0098] When the vehicle speed V is input to component A, an output signal is output from component A. Additionally, an output signal is output from component B. The output signal of component A is subtracted from the output signal of component B. The subtracted value is input to component C. Thus, the reference pressure Pref_pb is output as an output signal from component C.

[0099] The manual control valve HCV controls the relay valve RV to bring the parking brake chamber pressure Ppb to the reference pressure Pref_pb. It should be noted that the parking brake chamber pressure Ppb is detected by a pressure sensor (not shown). The manual control valve HCV controls the relay valve RV based on the pressure sensor's detection result.

[0100] As described above, when the parking brake 100P is activated, air is discharged from the parking brake chamber PBC, reducing the pressure in the parking brake chamber PBC. Additionally, air is discharged from the service brake chamber SBC, reducing the pressure in the service brake chamber SBC. Consequently, the parking brake chamber wall PBCW displaces from the back side to the front side under the restoring force of the second spring SPR2. Simultaneously, the brake pad BP moves from the back side to the front side via the rod LD, pressing the brake pad BP against the brake disc BD of the wheel. This generates braking force on the wheel.

[0101] Next, refer to Figure 6 Explain the relationship between the parking brake chamber pressure Ppb and the braking force of the brake disc. Figure 6 This is a schematic diagram illustrating an example of a wheel braking system. It should be noted that... Figure 6In the diagram, the parking brake chamber PBC and the second spring SPR2 in the wheel braking system are mainly represented. Additionally, the housing CS is used to represent the cylinder block. Figure 6 The description of the service brake chamber SBC and the first spring SPR1 is omitted. In the following description, the parking brake chamber PBC, the second spring SPR2, and the cylinder (housing CS) will be mainly described, while the description of the service brake chamber SBC and the first spring SPR1 will be omitted.

[0102] It should be noted that, in Figure 6 In the middle, A pb K is the cross-sectional area of ​​the cylinder block. pb Let P be the spring constant of the second spring SPR2. pb q represents the parking brake chamber pressure. pb The parking brake air chamber flow rate, m pb For brake pad mass, y pb For displacement.

[0103] The equation of motion for the wheel braking system is represented by the following equation (4).

[0104] (4)

[0105] Where, m pb For brake pad mass, y pb Let C be the displacement, C be the damping coefficient (frictional resistance) in the mechanical vibration system, and K be the displacement. pb Let y be the spring constant of the second spring SPR2. pr A is the pre-deformation amount of the second spring SPR2. pb P is the cross-sectional area of ​​the cylinder block. pb This refers to the pressure in the parking brake chamber.

[0106] Next, the state equation of the wheel braking system is represented by the following equation (5).

[0107] (5)

[0108] Among them, y pb For displacement, c pb m is the damping coefficient (frictional resistance) in a mechanical vibration system. pb For brake pad quality, K pb Let A be the spring constant of the second spring SPR2. pb Let y be the cross-sectional area of ​​the cylinder block. pr P is the pre-deformation amount of the second spring SPR2. pb This refers to the pressure in the parking brake chamber.

[0109] Next, the output equation of the wheel braking system is represented by the following equation (6).

[0110] (6)

[0111] Among them, y pb For displacement, F cpb For the brake disc, K pb Let A be the spring constant of the second spring SPR2. pb Let y be the cross-sectional area of ​​the cylinder block. pr P is the pre-deformation amount of the second spring SPR2. pb This refers to the pressure in the parking brake chamber.

[0112] As described above, in the wheel braking system, the FF control unit (second control unit) controls the pressure of the parking brake chamber according to the vehicle speed. This allows for adjustment of the brake disc pressing force generated by the force of the second spring SPR2. Thus, driving stability can be improved by adjusting the brake disc pressing force when the parking brake is engaged.

[0113] The braking system 100 of the present disclosure is a braking system having a service brake 100S capable of generating braking force on the wheels of a vehicle and a parking brake 100P capable of generating braking force on the wheels of a vehicle, and having an ABS device that controls the braking force of the wheels according to the vehicle speed and an FF control device that controls the braking force of the wheels according to the vehicle speed.

[0114] With the above structure, the FF control device controls the braking force of the wheels according to the vehicle speed, thus improving driving stability when the parking brake is activated.

[0115] Furthermore, the embodiments of this disclosure also include a parking brake chamber (PBC) configured to adjust pressure to increase or decrease the braking force on the wheels, and the FF control device controls the pressure of the parking brake chamber according to the vehicle speed. Thus, by controlling the pressure of the parking brake chamber through the FF control device, the braking force on the wheels can be increased or decreased. As a result, driving stability when the parking brake is engaged can be improved.

[0116] Furthermore, in the embodiments of this disclosure, air is discharged from the relay valve RV and from the interior of the parking brake chamber PBC via the relay valve RV. The FF control device controls the relay valve RV to reduce the pressure in the parking brake chamber from a high-pressure state. Therefore, by controlling the relay valve RV with the FF control device, the pressure in the parking brake chamber can be regulated, thereby improving driving stability when the parking brake is engaged.

[0117] Furthermore, in the above embodiments, the FF control device controls the pressure of the parking brake chamber based on the vehicle speed. However, in this disclosure, the FF control device can also control the pressure of the parking brake chamber based on both the vehicle speed and the wheel speed. In this case, for example, the wheel speed can be measured using a known wheel speed sensor capable of detecting the rotational speed of the wheels. This further improves driving stability when the parking brake is engaged. Moreover, in this disclosure, the braking force applied to each of the multiple wheels can be independently controlled based on the vehicle's yaw rate (the angular velocity of rotation about a vertical axis passing through the vehicle's center of gravity). This suppresses wheel spin, thereby further improving vehicle driving stability. It should be noted that the vehicle's yaw rate can be detected by a sensor.

[0118] Furthermore, in the above embodiments, the FF control device may independently control the braking force for each of the multiple wheels based on the vehicle's sideslip speed. Thus, the braking force for each wheel is appropriately controlled, enabling recovery from a sideslip.

[0119] (Modified Example)

[0120] Next, refer to Figure 7 This section describes variations of the braking system according to embodiments of the present disclosure. Figure 7 This is a block diagram illustrating a modified example of the braking system according to this embodiment. In the description of the modified example, structures different from those in the above embodiment are mainly described; descriptions of identical structures are omitted.

[0121] like Figure 3 As shown, the braking system of the above embodiment includes a pneumatic circuit in which compressed air (air) from the tank TNK flows into the relay valve RV through the multi-circuit protection valve MPV, the manual control valve HCV, and the double check valve. In contrast, in Figure 7 In the braking system of the modified example shown, air from the tank TNK flows directly into the pneumatic circuit of the relay valve RV from the multi-circuit protection valve MPV, and an electric parking brake switch EPS is provided. The control unit 110 determines the state of the electric parking brake switch EPS and controls the relay valve RV based on the determination result.

[0122] In the modified braking system, the driving stability when the parking brake is activated can be improved through a simpler structure than that described above.

[0123] Furthermore, the above embodiments are merely specific examples of implementing this disclosure, and the technical scope of this disclosure should not be limited to these embodiments. That is, this disclosure can be implemented in various forms without departing from its essential points or main features.

[0124] Industrial applicability

[0125] This disclosure is suitable for vehicles with braking systems that require improved driving stability when the parking brake is engaged.

Claims

1. A braking system comprising a service brake capable of generating a first braking force on a vehicle and a parking brake capable of generating a second braking force on the vehicle, the braking system being characterized in that it includes: The hardware processor controls the first braking force based on the vehicle's speed, and controls the second braking force based on the vehicle's speed.

2. The braking system as claimed in claim 1, wherein, The braking system also includes a parking brake chamber, which is configured to adjust the pressure to increase or decrease the second braking force. The hardware processor controls the pressure of the parking brake chamber based on the vehicle speed.

3. The braking system as claimed in claim 1, wherein, The hardware processor also controls the second braking force based on the vehicle's yaw rate.

4. The braking system as claimed in claim 1, wherein, The hardware processor also controls the second braking force based on the vehicle's sideslip speed.

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