Brake pressure rationality detection method and device and vehicle

Abstract

The application provides a brake pressure rationality detection method and device and a vehicle. The rigidity monitoring is performed based on an absolute value judgment standard method and a gradient judgment standard method. The current servo cylinder rigidity hard threshold and the current servo cylinder rigidity soft threshold corresponding to the current pedal push rod displacement are obtained according to a servo cylinder rigidity hard threshold curve and a servo cylinder rigidity soft threshold curve. The current servo cylinder pressure is compared with the current servo cylinder rigidity soft threshold and the current servo cylinder rigidity hard threshold respectively. The current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure is obtained by calculation. The pressure-volume characteristic curve is obtained according to the servo cylinder volume corresponding to different current servo cylinder pressures. The current servo cylinder pressure gradient corresponding to the current servo cylinder pressure is obtained according to the pressure-volume characteristic curve, so that the vehicle brake force deficiency problem is greatly avoided, and the safety of the integrated brake system is improved.

Description

Technical Field

[0001] This invention relates to the technical field of automobiles, specifically to a method, device, and vehicle for detecting the rationality of braking pressure. Background Technology

[0002] The braking system is one of the most important safety components of a car, and its performance is directly related to the life and property safety of the driver and passengers. For newer steerable hydraulic braking systems, the reliability of integrated braking systems (IBC) is lower than that of vacuum-assisted hydraulic braking systems, making braking safety even more critical. Insufficient braking force can cause a series of serious problems, which not only affect the driving experience but, more importantly, may threaten driving safety. The hydraulic stiffness and braking force of the braking system are important indicators for evaluating braking performance. To avoid insufficient braking force and improve the safety of integrated braking systems, this patent proposes a method for testing the rationality of braking pressure applicable to integrated braking control systems. Summary of the Invention This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a method, device, and vehicle for detecting the rationality of braking pressure, allowing the driver to monitor the hydraulic stiffness and braking force rationality of the braking system in real time while driving, greatly avoiding the occurrence of insufficient braking force and improving the safety of the integrated braking system.

[0003] According to a first aspect of the present invention, a method for detecting the rationality of braking pressure is applicable to a vehicle having an integrated braking system, the integrated braking system having a servo cylinder and a brake pedal, the method for detecting the rationality of braking pressure includes stiffness monitoring, the stiffness monitoring including an absolute value-based judgment standard method and a gradient-based judgment standard method; The absolute value-based judgment criterion method includes: Get the current servo cylinder pressure and the current pedal push rod displacement; The hard threshold curve and soft threshold curve of servo cylinder stiffness are obtained by calculation. The current servo cylinder stiffness hard threshold and current servo cylinder stiffness soft threshold corresponding to the current pedal push rod displacement are obtained based on the servo cylinder stiffness hard threshold curve and the servo cylinder stiffness soft threshold curve. When the current servo cylinder pressure is lower than the current servo cylinder stiffness soft threshold, a servo cylinder soft fault is reported. When the current servo cylinder pressure is higher than the current servo cylinder stiffness hard threshold, a servo cylinder hard fault is reported. The gradient-based judgment standard method includes: Get the current servo cylinder pressure and servo cylinder volume; The current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure is obtained by calculation. Based on the servo cylinder volume corresponding to different current servo cylinder pressures, a pressure-volume characteristic curve is obtained; The pressure gradient of the current servo cylinder corresponding to the current servo cylinder pressure is obtained based on the pressure-volume characteristic curve. When the pressure gradient of the current servo cylinder exceeds the calibrated pressure gradient threshold of the current servo cylinder, an alarm will be issued to the driver.

[0004] The braking pressure rationality detection method according to embodiments of the present invention has at least the following beneficial effects: The brake pressure rationality detection method of this invention simultaneously monitors stiffness using both an absolute value-based judgment standard method and a gradient-based judgment standard method. The absolute value-based judgment standard involves calculating the servo cylinder stiffness hard threshold curve and soft threshold curve; then, based on these curves, determining the current servo cylinder stiffness hard threshold and soft threshold corresponding to the current pedal push rod displacement; reporting a soft servo cylinder fault when the current servo cylinder pressure is below the soft threshold, and a hard servo cylinder fault when the current servo cylinder pressure is above the hard threshold. The gradient-based judgment standard involves calculating the current servo cylinder pressure relative to the hard threshold... The system calculates the current servo cylinder's calibrated pressure gradient threshold; it obtains a pressure-volume characteristic curve based on the servo cylinder volume corresponding to different current servo cylinder pressures; it then calculates the current servo cylinder pressure gradient corresponding to the current servo cylinder pressure based on the pressure-volume characteristic curve; and it issues an alarm to the driver when the current servo cylinder pressure gradient exceeds the current servo cylinder's calibrated pressure gradient threshold. This allows the driver to monitor the hydraulic stiffness and braking force rationality of the braking system in real time while driving, greatly reducing the occurrence of insufficient braking force and improving the safety of the integrated braking system. The integrated braking control system's pressure rationality detection is of great significance for ensuring driving safety, preventing system damage, and improving the driving experience.

[0005] According to some embodiments of the present invention, the braking pressure rationality detection method further includes braking force monitoring, wherein the braking force monitoring includes: Obtain driver braking demand information; The target servo cylinder pressure is obtained through calculation; When the target servo cylinder pressure is greater than a first preset value and the current servo cylinder pressure is less than a second preset value, a braking force insufficient fault is reported.

[0006] According to some embodiments of the present invention, the integrated braking system includes a front brake and a rear brake; The calculated target servo cylinder pressure includes: The ratio of braking torque to pressure of the front brake was calculated. The ratio of the braking torque to the pressure of the rear brake. : The braking force of the entire vehicle is calculated as follows: ,in, For the braking force of the whole vehicle, For the overall vehicle quality, For braking deceleration; According to the formula for calculating braking torque The formula for calculating the target servo cylinder pressure is obtained by conversion. The target servo cylinder pressure p is calculated, where This is the rolling radius of the wheel.

[0007] According to some embodiments of the present invention, the ratio of braking torque to pressure of the front brake is calculated. The ratio of the braking torque to the pressure of the rear brake. ,include: Through formula Calculated ,in, The piston diameter of the front brake is [missing information]. The friction coefficient of the front brake is given. The effective braking radius of the front brake; Through formula Calculated ,in The diameter of the rear brake piston is [missing information]. The friction coefficient of the rear brake is given. The effective braking radius of the rear brake is given.

[0008] According to some embodiments of the present invention, the integrated braking system further comprises a master cylinder connected between the brake pedal and the servo cylinder; The calculation of the target servo cylinder pressure also includes: Based on the test vehicle, a third calibration relationship curve between the first deceleration and the pedal push rod displacement, and a fourth calibration relationship curve between the second deceleration and the master cylinder pressure were determined. Get the current master cylinder pressure and the current pedal pushrod displacement; The current first deceleration corresponding to the current pedal push rod displacement is obtained based on the third calibration relationship curve. ; The current first deceleration corresponding to the current master cylinder pressure is obtained based on the third calibration relationship curve. ; Through formula The braking deceleration was calculated. ,in , These are different weighting coefficients, and .

[0009] According to some embodiments of the present invention, the step of calculating the target servo cylinder pressure further includes: Based on the test vehicle, a fifth calibration relationship curve between master cylinder pressure and braking deceleration was determined; When the integrated braking system's drive-by-wire mode fails, the driver presses the brake pedal to obtain the current master cylinder pressure, and then obtains the braking deceleration corresponding to the current master cylinder pressure according to the fifth calibration relationship curve.

[0010] According to some embodiments of the present invention, the step of calculating the hard threshold curve and soft threshold curve of the servo cylinder stiffness includes: Based on the test calibration vehicle, the first calibration relationship curve of the servo cylinder pressure of the integrated braking system as a function of pedal push rod displacement was determined. Based on the first calibration relationship curve, the hard threshold curve and soft threshold curve of servo cylinder stiffness are calculated.

[0011] According to some embodiments of the present invention, the step of calculating the servo cylinder stiffness hard threshold curve and the servo cylinder stiffness soft threshold curve based on the first calibration relationship curve includes: The hard tolerance and soft tolerance of servo cylinder stiffness are obtained based on the calculation results of component tolerances and disk clearance. The hard tolerance and soft tolerance of the servo cylinder stiffness are added to the first calibration relationship curve to obtain the hard threshold curve and the soft threshold curve of the servo cylinder stiffness.

[0012] According to some embodiments of the present invention, the step of calculating the current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure includes: Based on the test calibration vehicle, a second calibration relationship curve of the servo cylinder calibration pressure gradient threshold of the integrated braking system as a function of servo cylinder pressure was determined. The current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure is calculated based on the second calibration relationship curve.

[0013] According to a second aspect of the present invention, a brake pressure rationality detection device includes: The data acquisition module is used to acquire the current servo cylinder pressure and the current pedal push rod displacement; it is also used to acquire the current servo cylinder pressure and servo cylinder volume. The calculation and processing module is used to calculate the hard threshold curve and soft threshold curve of the servo cylinder stiffness; to calculate the hard threshold and soft threshold of the current servo cylinder stiffness corresponding to the current pedal push rod displacement based on the hard threshold curve and soft threshold curve of the servo cylinder stiffness; to calculate the current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure; to obtain the pressure-volume characteristic curve based on the servo cylinder volume corresponding to different current servo cylinder pressures; and to obtain the current servo cylinder pressure gradient corresponding to the current servo cylinder pressure based on the pressure-volume characteristic curve. The judgment module is used to report a soft fault in the servo cylinder when the current servo cylinder pressure is lower than the soft threshold of the current servo cylinder stiffness; to report a hard fault in the servo cylinder when the current servo cylinder pressure is higher than the hard threshold of the current servo cylinder stiffness; and to provide an alarm prompt to the driver when the current servo cylinder pressure gradient exceeds the current servo cylinder calibrated pressure gradient threshold.

[0014] A vehicle according to a third aspect of an embodiment of the present invention includes the aforementioned brake pressure rationality detection device.

[0015] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a flowchart of the absolute value-based judgment standard method of the present invention; Figure 2 This is a flowchart illustrating the calculation of the hard threshold curve and soft threshold curve of the servo cylinder stiffness according to the present invention. Figure 3 This is a flowchart illustrating how the hard threshold curve and soft threshold curve of servo cylinder stiffness are calculated based on the first calibration relationship curve according to the present invention. Figure 4 This is a diagram showing the relationship between the servo cylinder pressure and the pedal push rod displacement of the present invention. Figure 5 This is a flowchart of the gradient-based judgment standard method of the present invention; Figure 6 This is a flowchart illustrating the calculation of the current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure in this invention. Figure 7 This is a graph showing the relationship between the servo cylinder pressure and the servo cylinder pressure gradient in this invention. Figure 8 This is a diagram showing the relationship between the servo cylinder pressure and the servo cylinder volume in this invention. Figure 9 This is a flowchart of the braking force monitoring process of the present invention; Figure 10 This is a schematic diagram of the brake pressure rationality detection device of the present invention. Detailed Implementation

[0017] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0018] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0019] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0020] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are some embodiments of the present invention, not all embodiments.

[0022] The braking system is one of the most important safety components of a car, and its performance directly affects the life and property safety of the driver and passengers. Braking system pressure is a crucial indicator for evaluating braking performance. Traditional hydraulic braking systems are vacuum-assisted, and their braking force is tested on a roller brake test bench when new cars roll off the production line. Due to their high reliability and the fact that they only have a master cylinder pressure sensor (which is relatively few in number), software-based testing of pressure reliability during vehicle use is not currently available. For newer drive-by-wire hydraulic braking systems, the integrated brake system (IBC) has lower reliability than vacuum-assisted hydraulic braking systems, making braking safety even more critical.

[0023] Insufficient braking force can cause a series of serious problems, which not only affect the driving experience but, more importantly, may pose a threat to driving safety: Increased braking distance: Insufficient braking force causes the vehicle to require a longer distance to come to a complete stop, which can lead to serious traffic accidents in emergency situations.

[0024] Sluggish braking response: When the driver presses the brake pedal, if the braking force is insufficient, the vehicle may not decelerate immediately, requiring the driver to take longer to react, increasing the risk of an accident.

[0025] Unstable braking performance: Insufficient braking force may cause the braking effect to be inconsistent, making it difficult for the driver to accurately judge the vehicle's braking performance, thereby increasing the difficulty and danger of driving.

[0026] This invention provides a method for detecting the rationality of braking pressure in integrated braking systems. The driver can monitor the hydraulic stiffness and braking force of the braking system in real time while driving the vehicle, which greatly avoids the problem of insufficient braking force and improves the safety of integrated braking systems.

[0027] The integrated braking system includes a servo cylinder, a brake pedal, and a master cylinder. The brake pedal acts on the master cylinder, which provides foot-feel hydraulic pressure to the brake pedal while transmitting a braking signal to the servo cylinder. The servo cylinder is driven by a motor to perform the braking action. The travel of the brake pedal is detected by the displacement of the pedal push rod. The pressure and displacement of the servo cylinder can be measured and obtained by the pressure sensor and motor angle sensor built into the system, respectively. The volume of the servo cylinder is calculated by the displacement of the servo cylinder.

[0028] This application targets an integrated braking system. First, it collects pedal push rod displacement, servo cylinder displacement, and pressure signals through push rod stroke, servo cylinder and master cylinder pressure, and motor angle sensors built into the integrated braking control assembly. Then, it performs discrete differentiation on the motor angle to obtain the motor speed signal. At the same time, it converts the servo cylinder displacement into the servo cylinder volume. The pressure-volume characteristics of the entire braking system are obtained by using the servo cylinder pressure on the horizontal axis and the servo cylinder volume on the vertical axis.

[0029] Integrated braking systems are common in the industry, and their specific structure is not the focus of this application, so it will not be elaborated upon.

[0030] In some embodiments, the braking pressure rationality detection method of this application may include, but is not limited to, stiffness monitoring, wherein stiffness monitoring includes an absolute value-based judgment standard method and a gradient-based judgment standard method.

[0031] like Figure 1 As shown, this application provides an optional flowchart of a method for determining criteria based on absolute values. Figure 1 The absolute value-based judgment criterion method may include, but is not limited to, steps S101 to S105: Step S101: Obtain the current servo cylinder pressure and the current pedal push rod displacement; Step S102: Calculate the hard threshold curve and soft threshold curve of the servo cylinder stiffness. Step S103: Obtain the current servo cylinder stiffness hard threshold and current servo cylinder stiffness soft threshold corresponding to the current pedal push rod displacement based on the servo cylinder stiffness hard threshold curve and servo cylinder stiffness soft threshold curve. Step S104: When the current servo cylinder pressure is lower than the current servo cylinder stiffness soft threshold, report a servo cylinder soft fault. Step S105: When the current servo cylinder pressure is higher than the current servo cylinder stiffness hard threshold, report a servo cylinder hard fault.

[0032] This application calculates the hard threshold curve and soft threshold curve of servo cylinder stiffness; based on the hard threshold curve and soft threshold curve of servo cylinder stiffness, it obtains the current hard threshold and soft threshold of servo cylinder stiffness corresponding to the current pedal push rod displacement; when the current servo cylinder pressure is lower than the current soft threshold of servo cylinder stiffness, a soft fault of servo cylinder is reported; when the current servo cylinder pressure is higher than the current hard threshold of servo cylinder stiffness, a hard fault of servo cylinder is reported.

[0033] In step S101, the current servo cylinder pressure and the current pedal push rod displacement are detected and acquired by the pressure sensor and the displacement sensor, respectively.

[0034] Please see Figure 2 , Figure 2 This is a flowchart illustrating the calculation of the hard threshold curve and soft threshold curve of the servo cylinder stiffness provided in the embodiments of this application.

[0035] In some embodiments, step S102 may include, but is not limited to, steps S112 and S122: Step S112: Based on the test calibration vehicle, calibrate the first calibration relationship curve of the servo cylinder pressure of the integrated braking system as a function of the pedal push rod displacement; Step S122: Based on the first calibration relationship curve, the hard threshold curve and soft threshold curve of the servo cylinder stiffness are calculated.

[0036] In step S112, a first calibration relationship curve is obtained through a limited number of tests based on different vehicle models. The first calibration relationship curve is determined based on the initial design.

[0037] Please see Figure 3 , Figure 3This is a flowchart provided in an embodiment of the present application, showing how the hard threshold curve and soft threshold curve of the servo cylinder stiffness are calculated based on the first calibration relationship curve.

[0038] In some embodiments, step S122 may include, but is not limited to, steps S1221 and S1222: Step S1221: Based on the calculation results of component tolerances and disk clearance, obtain the hard tolerance and soft tolerance of servo cylinder stiffness; Step S1222: Add the servo cylinder stiffness hard tolerance and servo cylinder stiffness soft tolerance to the first calibration relationship curve, respectively, to obtain the servo cylinder stiffness hard threshold curve and the servo cylinder stiffness soft threshold curve. For example... Figure 4 The relationship between servo cylinder pressure and pedal push rod displacement is shown, where the horizontal axis represents pedal push rod displacement and the vertical axis represents servo cylinder pressure.

[0039] In step S103, the driver continuously monitors the pedal push rod displacement of the braking system during braking, and through... Figure 4 From the hard threshold curve and soft threshold curve of servo cylinder stiffness, the current hard threshold and soft threshold of servo cylinder stiffness corresponding to the current pedal push rod displacement are obtained.

[0040] The driver continuously monitors the servo cylinder pressure of the braking system during braking, through... Figure 4 If the current servo cylinder pressure is within the range between the servo cylinder stiffness hard threshold curve and the servo cylinder stiffness soft threshold curve, no fault will be reported.

[0041] If the current servo cylinder pressure is outside the region between the servo cylinder stiffness hard threshold curve and the servo cylinder stiffness soft threshold curve, then when the current servo cylinder pressure is lower than the current servo cylinder stiffness soft threshold, a servo cylinder soft fault will be reported; when the current servo cylinder pressure is higher than the current servo cylinder stiffness hard threshold, a servo cylinder hard fault will be reported.

[0042] like Figure 5 As shown, this application provides an optional flowchart of a gradient-based judgment criterion method. Figure 5 The gradient-based judgment standard method may include, but is not limited to, steps S201 to S205: Step S201: Obtain the current servo cylinder pressure and servo cylinder volume; Step S202: Calculate the current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure; Step S203: Obtain the pressure-volume characteristic curve based on the servo cylinder volume corresponding to different current servo cylinder pressures; Step S204: Obtain the current servo cylinder pressure gradient corresponding to the current servo cylinder pressure based on the pressure-volume characteristic curve; Step S205: When the current servo cylinder pressure gradient exceeds the current servo cylinder calibrated pressure gradient threshold, an alarm is issued to the driver.

[0043] This application calculates the current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure; obtains a pressure-volume characteristic curve based on the servo cylinder volume corresponding to different current servo cylinder pressures; obtains the current servo cylinder pressure gradient corresponding to the current servo cylinder pressure based on the pressure-volume characteristic curve; and provides an alarm prompt to the driver when the current servo cylinder pressure gradient exceeds the current servo cylinder calibration pressure gradient threshold.

[0044] Please see Figure 6 , Figure 6 This is a flowchart illustrating the calculation of the current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure, provided in an embodiment of this application.

[0045] In some embodiments, step S202 may include, but is not limited to, steps S212 and S222: Step S212: Based on the test calibration vehicle, calibrate the second calibration relationship curve of the servo cylinder calibration pressure gradient threshold of the integrated braking system as a function of servo cylinder pressure; Step S222: Calculate the current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure based on the second calibration relationship curve.

[0046] like Figure 7 The second calibration relationship curve shown represents the relationship between the servo cylinder calibration pressure gradient gate and the servo cylinder pressure. The horizontal axis represents the servo cylinder pressure, and the vertical axis represents the servo cylinder pressure gradient. Based on this second calibration relationship curve, the pressure gradient at the current servo cylinder pressure can be obtained. Below, the corresponding current servo cylinder calibration pressure gradient threshold.

[0047] In step S203, the driver continuously monitors the pressure-volume characteristics of the braking system during braking, and obtains the servo cylinder volume corresponding to different servo cylinder pressures in real time to obtain the pressure-volume characteristic curve, such as... Figure 8 As shown, the horizontal axis represents the servo cylinder pressure, and the vertical axis represents the servo cylinder volume.

[0048] In step S204, based on the pressure-volume characteristic curve, according to the formula... The calculated pressure of the current servo cylinder is... Current servo cylinder pressure gradient ,in, For the change in servo cylinder volume, p represents the change in servo cylinder pressure. Based on real-time data acquisition, a sixth calibration relationship curve is fitted between the servo cylinder pressure gradient and the servo cylinder pressure, as shown below. Figure 7 As shown.

[0049] In step S205, according to... Figure 7 The relationship between the sixth calibration curve and the second calibration curve is shown, under the current servo cylinder pressure. If the current servo cylinder pressure gradient is below... If the pressure gradient exceeds the current servo cylinder's calibrated threshold, an alarm will be issued to the driver.

[0050] In some embodiments, the brake pressure rationality detection method further includes brake force monitoring, as shown in Figure 9, which is an optional flowchart of brake force monitoring provided in an embodiment of this application. Figure 9 Braking force monitoring may include, but is not limited to, steps S301 to S303: Step S301: Obtain driver braking demand information; Step S302: Calculate the target servo cylinder pressure; Step S303: When the target servo cylinder pressure is greater than the first preset value and the current servo cylinder pressure is less than the second preset value, a braking force insufficient fault is reported.

[0051] This application obtains the driver's braking demand information and calculates the target servo cylinder pressure. When the target servo cylinder pressure is greater than a first preset value and the current servo cylinder pressure is less than a second preset value, an insufficient braking force fault is reported.

[0052] Because the brake disc clearance varies significantly when the vehicle is traveling on uneven roads or under large lateral acceleration, and because drivers of vehicles with insufficient braking can increase braking demand to achieve higher target pressure requirements, considering the above situations, when the target servo cylinder pressure is lower than the first preset value, pressure rationality monitoring is not performed; when the target servo cylinder pressure is higher than the first preset value, and the current servo cylinder pressure is higher than the second preset value, pressure rationality monitoring is performed, but no fault is reported; and when the target servo cylinder pressure is higher than the first preset value, and the current servo cylinder pressure is lower than the second preset value, an insufficient braking force fault is reported.

[0053] The first preset value and the second preset value are determined according to different vehicle models. In this embodiment, the first preset value is 70 bar, and the second preset value is 30 bar.

[0054] The integrated braking system of this embodiment includes a front brake and a rear brake, which brake the rear wheels and front wheels of the vehicle, respectively.

[0055] Step S302 in this embodiment may include, but is not limited to, steps S312 to S332: Step S312: Calculate the ratio of the braking torque to the pressure of the front brake. The ratio of braking torque to pressure of the rear brake : Step S322: Calculate the braking force of the entire vehicle: ,in, For the braking force of the whole vehicle, For the overall vehicle quality, For braking deceleration; Step S332: According to the calculation formula of braking torque The formula for calculating the target servo cylinder pressure is obtained through conversion. The target servo cylinder pressure p is calculated, where This is the rolling radius of the wheel.

[0056] Step S312 in this embodiment may include, but is not limited to, steps S3121 and S3122: Step S3121: Using the formula Calculated ,in, The diameter of the piston in the front brake. The coefficient of friction of the front brake. The effective braking radius of the front brake; Step S3122: Using the formula Calculated ,in The diameter of the rear brake piston is [missing information]. The friction coefficient of the rear brake is given. The effective braking radius of the rear brake is given.

[0057] Furthermore, step S302 may include, but is not limited to, steps S342 to S382: Step S342: Based on the test calibration vehicle, calibrate the third calibration relationship curve between the first deceleration and the pedal push rod displacement, and the fourth calibration relationship curve between the second deceleration and the master cylinder pressure; Step S352: Obtain the current master cylinder pressure and the current pedal push rod displacement; Step S362: Obtain the current first deceleration corresponding to the current pedal push rod displacement based on the third calibration relationship curve. ; Step S372: Obtain the current first deceleration corresponding to the current master cylinder pressure based on the third calibration relationship curve. ; Step S382: Using the formula The braking deceleration was calculated. ,in , These are different weighting coefficients, and .

[0058] In some embodiments, step S302 may include, but is not limited to, steps S3021 to S3022: Step S3021: Based on the test calibration vehicle, calibrate the fifth calibration relationship curve between master cylinder pressure and braking deceleration; Step S3022: When the integrated braking system's drive-by-wire mode fails, the driver depresses the brake pedal to obtain the current master cylinder pressure, and then calculates the braking deceleration corresponding to the current master cylinder pressure based on the fifth calibration curve. .

[0059] like Figure 10 As shown, this embodiment also proposes a brake pressure rationality detection device, the device comprising: The data acquisition module is used to acquire the current servo cylinder pressure and the current pedal push rod displacement; it is also used to acquire the current servo cylinder pressure and servo cylinder volume. The data acquisition module in this embodiment is also used to execute steps S301 and S352.

[0060] The calculation and processing module is used to calculate the hard threshold curve and soft threshold curve of the servo cylinder stiffness; to calculate the hard threshold and soft threshold of the current servo cylinder stiffness corresponding to the current pedal push rod displacement based on the hard threshold curve and soft threshold curve of the servo cylinder stiffness; to calculate the current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure; to obtain the pressure-volume characteristic curve based on the servo cylinder volume corresponding to different current servo cylinder pressures; and to obtain the current servo cylinder pressure gradient corresponding to the current servo cylinder pressure based on the pressure-volume characteristic curve. The calculation processing module in this embodiment is also used to execute steps S302, S342, S362, S372 and S382.

[0061] The judgment module is used to report a soft fault in the servo cylinder when the current servo cylinder pressure is lower than the soft threshold of the current servo cylinder stiffness; to report a hard fault in the servo cylinder when the current servo cylinder pressure is higher than the hard threshold of the current servo cylinder stiffness; and to provide an alarm prompt to the driver when the current servo cylinder pressure gradient exceeds the calibrated pressure gradient threshold of the current servo cylinder.

[0062] This embodiment is also used to execute step S303.

[0063] The specific implementation method of the brake pressure rationality detection device is basically the same as the specific implementation method of the brake pressure rationality detection method described above, and will not be repeated here.

[0064] According to embodiments of the present invention, a vehicle is also provided, including the aforementioned brake pressure rationality detection device. Specifically, the vehicle can be a private car, such as a sedan, SUV, MPV, or pickup truck. The vehicle can also be a commercial vehicle, such as a van, bus, small truck, or large trailer. The vehicle can be a gasoline-powered vehicle or a new energy vehicle. When the vehicle is a new energy vehicle, it can be a hybrid vehicle or a pure electric vehicle.

[0065] Since the vehicle applies all the technical solutions of the above-mentioned brake pressure rationality detection device, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0066] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0067] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for detecting the rationality of braking pressure, applicable to vehicles with integrated braking systems, characterized in that, The integrated braking system has a servo cylinder and a brake pedal. The braking pressure rationality detection method includes stiffness monitoring, which includes an absolute value-based judgment standard method and a gradient-based judgment standard method. The absolute value-based judgment criterion method includes: Get the current servo cylinder pressure and the current pedal push rod displacement; The calculation of the servo cylinder stiffness hard threshold curve and servo cylinder stiffness soft threshold curve includes: calibrating a first calibration relationship curve of the servo cylinder pressure as a function of pedal push rod displacement in the integrated braking system based on the test calibration vehicle; calculating the servo cylinder stiffness hard threshold curve and servo cylinder stiffness soft threshold curve based on the first calibration relationship curve, specifically including: calculating the servo cylinder stiffness hard tolerance and servo cylinder stiffness soft tolerance based on component tolerances and disc clearance; adding the servo cylinder stiffness hard tolerance and the servo cylinder stiffness soft tolerance to the first calibration relationship curve respectively to obtain the servo cylinder stiffness hard threshold curve and servo cylinder stiffness soft threshold curve. The current servo cylinder stiffness hard threshold and current servo cylinder stiffness soft threshold corresponding to the current pedal push rod displacement are obtained based on the servo cylinder stiffness hard threshold curve and the servo cylinder stiffness soft threshold curve. When the current servo cylinder pressure is lower than the current servo cylinder stiffness soft threshold, a servo cylinder soft fault is reported. When the current servo cylinder pressure is higher than the current servo cylinder stiffness hard threshold, a servo cylinder hard fault is reported. The gradient-based judgment standard method includes: Get the current servo cylinder pressure and servo cylinder volume; The current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure is obtained by calculation. Based on the servo cylinder volume corresponding to different current servo cylinder pressures, a pressure-volume characteristic curve is obtained; The pressure gradient of the current servo cylinder corresponding to the current servo cylinder pressure is obtained based on the pressure-volume characteristic curve. When the pressure gradient of the current servo cylinder exceeds the calibrated pressure gradient threshold of the current servo cylinder, an alarm will be issued to the driver.

2. The method for detecting the rationality of braking pressure according to claim 1, characterized in that, The braking pressure rationality detection method further includes braking force monitoring, which includes: Obtain driver braking demand information; The target servo cylinder pressure is obtained through calculation; When the target servo cylinder pressure is greater than a first preset value and the current servo cylinder pressure is less than a second preset value, a braking force insufficient fault is reported.

3. The method for detecting the rationality of braking pressure according to claim 2, characterized in that, The integrated braking system includes a front brake and a rear brake; The calculated target servo cylinder pressure includes: The ratio of braking torque to pressure of the front brake was calculated. The ratio of the braking torque to the pressure of the rear brake. : The braking force of the entire vehicle is calculated as follows: ,in, For the braking force of the whole vehicle, For the overall vehicle quality, For braking deceleration; According to the formula for calculating braking torque The formula for calculating the target servo cylinder pressure is obtained by conversion. The target servo cylinder pressure p is calculated, where This is the rolling radius of the wheel.

4. The method for detecting the rationality of braking pressure according to claim 3, characterized in that, The ratio of braking torque to pressure of the front brake is calculated. The ratio of the braking torque to the pressure of the rear brake. ,include: Through formula Calculated ,in, The piston diameter of the front brake is [missing information]. The friction coefficient of the front brake is given. The effective braking radius of the front brake; Through formula Calculated ,in The diameter of the rear brake piston is [missing information]. The friction coefficient of the rear brake is given. The effective braking radius of the rear brake is given.

5. The method for detecting the rationality of braking pressure according to claim 4, characterized in that, The integrated braking system also has a master cylinder connected between the brake pedal and the servo cylinder; The calculation of the target servo cylinder pressure also includes: Based on the test vehicle, a third calibration relationship curve between the first deceleration and the pedal push rod displacement, and a fourth calibration relationship curve between the second deceleration and the master cylinder pressure were determined. Get the current master cylinder pressure and the current pedal pushrod displacement; The current first deceleration corresponding to the current pedal push rod displacement is obtained based on the third calibration relationship curve. ; The current second deceleration corresponding to the current master cylinder pressure is obtained based on the fourth calibration relationship curve. ; Through formula The braking deceleration was calculated. ,in , These are different weighting coefficients, and .

6. The method for detecting the rationality of braking pressure according to claim 1, characterized in that, The step of calculating the current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure includes: Based on the test calibration vehicle, a second calibration relationship curve of the servo cylinder calibration pressure gradient threshold of the integrated braking system as a function of servo cylinder pressure was determined. The current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure is calculated based on the second calibration relationship curve.

7. A device for detecting the rationality of braking pressure, characterized in that, The apparatus used in the brake pressure rationality detection method as described in any one of claims 1 to 6 comprises: The data acquisition module is used to acquire the current servo cylinder pressure and the current pedal push rod displacement; it is also used to acquire the current servo cylinder pressure and servo cylinder volume. The calculation and processing module is used to calculate the hard threshold curve and soft threshold curve of the servo cylinder stiffness; to calculate the hard threshold and soft threshold of the current servo cylinder stiffness corresponding to the current pedal push rod displacement based on the hard threshold curve and soft threshold curve of the servo cylinder stiffness; to calculate the current servo cylinder calibration pressure gradient threshold corresponding to the current servo cylinder pressure; to obtain the pressure-volume characteristic curve based on the servo cylinder volume corresponding to different current servo cylinder pressures; and to obtain the current servo cylinder pressure gradient corresponding to the current servo cylinder pressure based on the pressure-volume characteristic curve. The judgment module is used to report a soft fault in the servo cylinder when the current servo cylinder pressure is lower than the soft threshold of the current servo cylinder stiffness; to report a hard fault in the servo cylinder when the current servo cylinder pressure is higher than the hard threshold of the current servo cylinder stiffness; and to provide an alarm prompt to the driver when the current servo cylinder pressure gradient exceeds the current servo cylinder calibrated pressure gradient threshold.

8. A vehicle, characterized in that, Includes the brake pressure rationality detection device as described in claim 7.

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