CN117033861A - Wheel cylinder pressure estimation method and device for hydraulic braking system - Google Patents
Wheel cylinder pressure estimation method and device for hydraulic braking system Download PDFInfo
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- CN117033861A CN117033861A CN202311147124.8A CN202311147124A CN117033861A CN 117033861 A CN117033861 A CN 117033861A CN 202311147124 A CN202311147124 A CN 202311147124A CN 117033861 A CN117033861 A CN 117033861A
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
- B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
- B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
- G06F17/10—Complex mathematical operations
Abstract
The invention discloses a wheel cylinder pressure estimation method and a pressure estimation device of a hydraulic brake system. The wheel cylinder pressure estimation method includes: acquiring the pulse width modulation signal duty ratio of a high-speed switch valve; calculating the pressure difference of two ends of the high-speed switch valve according to the master cylinder pressure and the estimated pressure of the previous period; calculating the outlet flow of the high-speed switch valve according to the duty ratio of the pulse width modulation signal and the pressure difference between two ends of the high-speed switch valve; calculating a brake fluid volume change value according to the outlet flow meter of the high-speed switch valve; calculating the current brake fluid volume according to the brake fluid volume change value and the brake fluid volume in the wheel cylinder in the previous period, and determining the current wheel cylinder pressure estimated value according to the relation curve of the brake fluid pressure and the brake fluid volume and the current brake fluid volume; the relation curve of the brake fluid pressure and the brake fluid volume is updated according to a preset period through a data analysis platform, so that the estimated value of the wheel cylinder pressure is more accurate, and the safety performance of the motor vehicle is higher.
Description
Technical Field
The invention relates to the technical field of hydraulic braking, in particular to a wheel cylinder pressure estimation method and a pressure estimation device of a hydraulic braking system.
Background
Hydraulic braking systems are currently a popular form of maneuver for small and medium-sized motor vehicles. Hydraulic braking systems have found widespread use.
The existing brake pressure control method is to calibrate the relation between the wheel cylinder pressure variation and the increase and decrease pressure according to a fixed increase and decrease pressure mode. And determining the pressure increasing and reducing mode and the duration according to the calibration curve when the target pressure deviates from the actual pressure. However, the volume of the brake fluid flowing through the pressure increasing valve and the pressure reducing valve is influenced by factors such as the size of the brake pipeline material, the temperature of the brake fluid, the volume change of the brake fluid and the like, and an accurate model is difficult to be established to draw a change relation curve of the brake fluid pressure and the brake fluid volume.
Disclosure of Invention
The invention provides a wheel cylinder pressure estimation method and a pressure estimation device of a hydraulic braking system, so that an estimated value of the wheel cylinder pressure is more accurate, and the hydraulic braking system can brake with more accurate braking pressure, so that the safety performance of a motor vehicle is higher.
According to an aspect of the present invention, there is provided a wheel cylinder pressure estimation method of a hydraulic brake system, the wheel cylinder pressure estimation method including:
acquiring the pulse width modulation signal duty ratio of a high-speed switch valve;
calculating the pressure difference of two ends of the high-speed switch valve according to the master cylinder pressure and the estimated pressure of the previous period;
calculating the outlet flow of the high-speed switch valve according to the duty ratio of the pulse width modulation signal and the pressure difference between two ends of the high-speed switch valve;
calculating a brake fluid volume change value according to the outlet flow meter of the high-speed switch valve;
calculating the current brake fluid volume according to the brake fluid volume change value and the brake fluid volume in the wheel cylinder in the previous period, and determining the current wheel cylinder pressure estimated value according to the relation curve of the brake fluid pressure and the brake fluid volume and the current brake fluid volume; the relation curve of the brake fluid pressure and the brake fluid volume is updated according to a preset period through a data analysis platform.
Further, the data analysis platform updates the relation curve between the brake fluid pressure and the brake fluid volume according to a preset period, and the wheel cylinder pressure estimation method comprises the following steps:
and sending the wheel cylinder pressure, the brake fluid volume, the brake state, the high-speed electromagnetic valve state, the wheel speed signal, the vehicle speed signal, the generation time and the environmental temperature to the data analysis platform according to a preset period, so as to calculate the updated relation curve of the brake fluid pressure and the brake fluid volume according to the wheel cylinder pressure, the brake fluid volume, the brake state, the high-speed electromagnetic valve state, the wheel speed signal, the vehicle speed signal, the generation time and the environmental temperature through the data analysis platform.
Further, a hydraulic pressure sensor is installed in one of four wheel cylinders of the automobile, and the hydraulic pressure sensor is used for detecting the pressure of the wheel cylinder; after determining the current wheel cylinder pressure estimated value according to the relation between the brake fluid pressure and the brake fluid volume and the current brake fluid volume, the wheel cylinder pressure estimated method further includes:
and performing redundant comparison on the current wheel cylinder pressure estimated value and the wheel cylinder pressure detected by the hydraulic pressure sensor to judge whether the current wheel cylinder pressure estimated value is accurate or not and whether the hydraulic pressure sensor fails or not.
Further, the outlet flow of the high-speed switch valve is calculated according to the duty ratio of the pulse width modulation signal and the pressure difference between two ends of the high-speed switch valve, and is determined based on the following formula:
wherein τ is the pulse width modulation signal duty ratio of the high-speed switch valve, and Q is the outlet flow of the high-speed switch valve; c (C) d Is the flow coefficient; a is the flow area of a throttle orifice of the high-speed switching valve; Δp is the pressure difference across the high-speed switch valve; ρ is the hydraulic oil density; χ is the orifice wet circumference length; η is the brake fluid dynamic viscosity; lambda (lambda) c Is a critical reynolds number.
Further, the method for calculating the brake fluid volume change value according to the high-speed switching valve outlet flow meter includes:
and calculating a brake fluid volume change value according to the outlet flow of the high-speed switch valve and the time interval of the duty ratio of the twice pulse width modulation signals.
Further, the high-speed switching valve comprises a pressure increasing valve and a pressure reducing valve; calculating the outlet flow of the high-speed switch valve according to the duty ratio of the pulse width modulation signal and the pressure difference between two ends of the high-speed switch valve, comprising:
calculating the liquid flow flowing into the hydraulic system according to the pulse width modulation signal duty ratio of the booster valve and the pressure difference at two ends of the booster valve;
or calculating the liquid flow out of the liquid pressure system according to the pulse width modulation signal duty ratio of the pressure reducing valve and the pressure difference between two ends of the pressure reducing valve.
According to another aspect of the present invention, there is provided a wheel cylinder pressure estimation device of a hydraulic brake system, the wheel cylinder pressure estimation device including:
the duty cycle acquisition module is used for acquiring the duty cycle of the pulse width modulation signal of the high-speed switch valve;
the pressure difference calculation module is used for calculating the pressure difference of the two ends of the high-speed switch valve according to the master cylinder pressure and the estimated pressure of the previous period;
the outlet flow calculation module is used for calculating the outlet flow of the high-speed switch valve according to the duty ratio of the pulse width modulation signal and the pressure difference at the two ends of the high-speed switch valve;
the volume calculation module is used for calculating a brake fluid volume change value according to the high-speed switch valve outlet flow meter;
the current pressure determining module is used for calculating the current brake fluid volume according to the brake fluid volume change value and the brake fluid volume in the wheel cylinder in the previous period, and determining the current wheel cylinder pressure estimated value according to the relation curve of the brake fluid pressure and the brake fluid volume and the current brake fluid volume; the relation curve of the brake fluid pressure and the brake fluid volume is updated according to a preset period through a data analysis platform.
According to another aspect of the present invention, there is provided an automotive hydraulic brake system including a controller and a hydraulic system; the hydraulic system is used for providing wheel cylinder braking pressure, and the controller is used for controlling the wheel cylinder braking pressure of the hydraulic system;
wherein the controller includes the wheel cylinder pressure estimation device of the hydraulic brake system described in the above embodiment; the controller is connected with the data analysis platform; the data analysis platform is used for providing updated relation curves of brake fluid pressure and brake fluid volume for the controller according to a preset period.
Further, the controller includes an ECU control unit, an ABS control unit, an ESC control unit, an ESP control unit, or an one_box control unit.
According to another aspect of the present invention, there is provided an electronic apparatus including:
at least one processor; and
a memory communicatively coupled to the at least one processor; wherein,
the memory stores a computer program executable by the at least one processor to enable the at least one processor to perform the wheel cylinder pressure estimation method of the hydraulic brake system according to any one of the embodiments of the present invention.
According to the embodiment of the invention, the pulse width modulation signal duty ratio of the high-speed switch valve is obtained, the pressure difference at the two ends of the high-speed switch valve is calculated according to the master cylinder pressure and the estimated pressure of the previous period, and the outlet flow of the high-speed switch valve is calculated according to the pulse width modulation signal duty ratio and the pressure difference at the two ends of the high-speed switch valve; calculating a brake fluid volume change value according to the outlet flowmeter of the high-speed switch valve; calculating the current brake fluid volume according to the brake fluid volume change value and the brake fluid volume in the wheel cylinder in the previous period, and determining the current wheel cylinder pressure estimated value according to the relation curve of the brake fluid pressure and the brake fluid volume and the current brake fluid volume; the relation curve between the brake fluid pressure and the brake fluid volume is updated according to the preset period through the data analysis platform, and the estimated value of the wheel cylinder pressure is more accurate by using the wheel cylinder pressure estimation method of the hydraulic brake system provided by the embodiment of the invention, so that the hydraulic brake system can brake with more accurate brake pressure, and the safety performance of the motor vehicle is higher.
It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the invention or to delineate the scope of the invention. Other features of the present invention will become apparent from the description that follows.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a flowchart of a wheel cylinder pressure estimation method of a hydraulic brake system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of data transfer provided in accordance with an embodiment of the present invention;
FIG. 3 is a flow chart of another method for estimating wheel cylinder pressure of a hydraulic brake system according to an embodiment of the invention;
fig. 4 is a schematic structural view of a wheel cylinder pressure estimation device of a hydraulic brake system according to an embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a hydraulic system provided in accordance with an embodiment of the present invention;
fig. 6 shows a schematic diagram of an electronic device that may be used to implement an embodiment of the invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
An embodiment of the present invention provides a method for estimating a wheel cylinder pressure of a hydraulic brake system, and fig. 1 is a flowchart of the method for estimating a wheel cylinder pressure of a hydraulic brake system according to an embodiment of the present invention, and referring to fig. 1, the method for estimating a wheel cylinder pressure includes:
s110, acquiring the pulse width modulation signal duty ratio of the high-speed switch valve.
Specifically, the pedal displacement of the motor vehicle can be collected in real time through the controller, the vehicle state is collected, the expected brake pressure of the driver, namely the expected wheel cylinder pressure, is calculated in real time, and meanwhile, the wheel cylinder pressure estimated value obtained in real time through the wheel cylinder pressure estimation method is used as the current actual wheel cylinder pressure, namely the current wheel cylinder pressure. The controller calculates the pulse width modulation signal duty ratio of the next period of the high-speed switch valve according to the expected pressure of the wheel cylinder and the current actual wheel cylinder pressure. The calculation frequency of the expected wheel cylinder pressure and the acquisition frequency of the current wheel cylinder pressure are kept the same, and the specific frequency can be designed according to actual conditions, so that the embodiment of the invention is not limited. Therefore, in the wheel cylinder pressure estimation method of the hydraulic braking system provided by the embodiment of the invention, the obtained pulse width modulation signal duty ratio of the high-speed switching valve is obtained by the controller according to the expected pressure of the wheel cylinder in the previous period and the actual wheel cylinder pressure at the beginning of the previous period.
And S120, calculating the pressure difference of the two ends of the high-speed switch valve according to the master cylinder pressure and the estimated pressure of the previous cycle.
Specifically, the master cylinder pressure may be obtained by a hydraulic pressure sensor mounted at the master cylinder by a controller, and the last cycle estimated pressure is the wheel cylinder pressure estimated value of the last cycle estimated and obtained according to the wheel cylinder pressure estimating method.
S130, calculating the outlet flow of the high-speed switch valve according to the duty ratio of the pulse width modulation signal and the pressure difference between two ends of the high-speed switch valve.
Specifically, the high-speed switch valve outlet flow rate can be calculated through the pulse width modulation signal duty ratio of the high-speed switch valve, the high-speed switch valve outlet flow rate, the flow coefficient, the flow area of the high-speed switch valve orifice, the pressure difference at two ends of the high-speed switch valve, the hydraulic oil density, the wet circumference length of the orifice, the brake hydrodynamic viscosity and the critical Reynolds number.
And S140, calculating a brake fluid volume change value according to the outlet flow meter of the high-speed switch valve.
Specifically, the brake fluid volume change value is calculated according to the outlet flow of the high-speed switching valve and the time interval of the duty ratio of the twice pulse width modulation signals.
S150, calculating the current brake fluid volume according to the brake fluid volume change value and the brake fluid volume in the wheel cylinder of the previous cycle, and determining the current wheel cylinder pressure estimated value according to the relation curve of the brake fluid pressure and the brake fluid volume and the current brake fluid volume; the relation curve of the brake fluid pressure and the brake fluid volume is updated according to a preset period through a data analysis platform.
Specifically, the current brake fluid volume is calculated according to the sum of the brake fluid volume change value and the brake fluid volume in the wheel cylinder of the previous cycle, and finally, the current wheel cylinder pressure estimated value is determined according to the relation curve of the brake fluid pressure and the brake fluid volume which are inquired by the current brake fluid volume. The update of the relation curve of the brake fluid pressure and the brake fluid volume needs to transmit the information of the current wheel cylinder pressure, the brake fluid volume and the like to the data analysis platform through the controller, and the more accurate relation curve of the brake fluid pressure and the brake fluid volume is formed through the big data processing of the data analysis platform, so that the estimated value of the wheel cylinder pressure is more accurate, further, the hydraulic brake system can brake the more accurate brake pressure, and the safety performance of the motor vehicle is higher. The preset period can be updated once a month, updated once two months, and the like, and the embodiment of the invention does not limit the updating, and the actual period is set according to different vehicle types.
According to the embodiment of the invention, the pulse width modulation signal duty ratio of the high-speed switch valve is obtained, the pressure difference at the two ends of the high-speed switch valve is calculated according to the master cylinder pressure and the estimated pressure of the previous period, and the outlet flow of the high-speed switch valve is calculated according to the pulse width modulation signal duty ratio and the pressure difference at the two ends of the high-speed switch valve; calculating a brake fluid volume change value according to the outlet flowmeter of the high-speed switch valve; calculating the current brake fluid volume according to the brake fluid volume change value and the brake fluid volume in the wheel cylinder in the previous period, and determining the current wheel cylinder pressure estimated value according to the relation curve of the brake fluid pressure and the brake fluid volume and the current brake fluid volume; the relation curve between the brake fluid pressure and the brake fluid volume is updated according to the preset period through the data analysis platform, and the estimated value of the wheel cylinder pressure is more accurate by using the wheel cylinder pressure estimation method of the hydraulic brake system provided by the embodiment of the invention, so that the hydraulic brake system can brake with more accurate brake pressure, and the safety performance of the motor vehicle is higher.
Fig. 2 is a schematic diagram of data transmission provided according to an embodiment of the present invention, and optionally, referring to fig. 2, a method for estimating a wheel cylinder pressure by updating a relation between a brake fluid pressure and a brake fluid volume according to a preset cycle through a data analysis plane 20 includes:
the wheel cylinder pressure 1, the brake fluid volume 2, the brake state 3, the high-speed electromagnetic valve state 4, the wheel speed signal 5, the vehicle speed signal 6, the occurrence time 7 and the ambient temperature 8 are sent to the data analysis platform 20 according to a preset period, so that the updated relation curve of the brake fluid pressure and the brake fluid volume is calculated according to the wheel cylinder pressure 1, the brake fluid volume 2, the brake state 3, the high-speed electromagnetic valve state 4, the wheel speed signal 5, the vehicle speed signal 6, the occurrence time 7 and the ambient temperature 8 through the data analysis platform 20.
The wheel cylinder pressure 1 may be estimated and determined according to the relationship between the brake fluid pressure and the brake fluid volume, or a hydraulic pressure sensor may be installed on a certain wheel cylinder of the motor vehicle, and the wheel cylinder pressure 1 is determined by the detection value of the hydraulic pressure sensor, which is not limited in the embodiment of the present invention. And the brake fluid volume 2 can be calculated according to the steps S130, S140 and S150. The braking state 3 and the high-speed solenoid valve state 4 can be detected in real time by a sensor. The wheel speed signal 5 can also be detected by a crankshaft rotation speed sensor, and the same vehicle speed signal 6 can be detected by a speed sensor in real time. Specifically, the occurrence time 7 is the service life of the motor vehicle, and the service life of the motor vehicle can be integrated with the increase of the service life when the relation curve of the brake fluid pressure and the brake fluid volume is integrated in the analysis data, so that the ageing factor of the motor vehicle can be integrated, and the relation curve of the brake fluid pressure and the brake fluid volume is more accurate. The environmental temperature 8 can be detected in real time through the temperature sensor, and the relation curve of the brake fluid pressure and the brake fluid volume under different environmental temperatures can be integrated in the analysis data by the environmental temperature 8, so that the accuracy of the relation curve of the brake fluid pressure and the brake fluid volume is further improved. The data analysis platform 20 performs data integration, data mining and data analysis on the data according to the data of the wheel cylinder pressure 1, the brake fluid volume 2, the brake state 3, the high-speed electromagnetic valve state 4, the wheel speed signal 5, the vehicle speed signal 6, the generation time 7, the ambient temperature 8 and the like acquired in real time, and calculates the updated relation curve of the brake fluid pressure and the brake fluid volume. For example, according to different ambient temperatures 8, a plurality of sets of curves of the relation between the brake fluid pressure and the brake fluid volume at different ambient temperatures are generated, so as to form a curve family changing with the temperature.
Optionally, a hydraulic sensor is installed in one of four wheel cylinders of the automobile, and the hydraulic sensor is used for detecting the pressure of the wheel cylinder; after determining the current wheel cylinder pressure estimated value according to the relation between the brake fluid pressure and the brake fluid volume and the current brake fluid volume, the wheel cylinder pressure estimated method further includes:
and performing redundant comparison on the current wheel cylinder pressure estimated value and the wheel cylinder pressure detected by the hydraulic pressure sensor to judge whether the current wheel cylinder pressure estimated value is accurate or not and whether the hydraulic pressure sensor fails or not.
Specifically, a hydraulic sensor is installed in one of four wheel cylinders of an automobile, the wheel cylinder pressure is detected in real time through the hydraulic sensor, when the difference value between the value detected by the hydraulic sensor and the current wheel cylinder pressure estimated value is large, whether the selection of a relation curve of the brake fluid pressure and the brake fluid volume at the ambient temperature is correct or not is firstly checked to determine the accuracy of the current wheel cylinder pressure estimated value, and if the relation curve of the selected brake fluid pressure and the brake fluid volume is found to be wrong, the relation curve of the brake fluid pressure and the brake fluid volume is reselected, and the current wheel cylinder pressure is reevaluated; if the relation curve between the selected brake fluid pressure and the brake fluid volume is found to be normal, the hydraulic sensor of the motor vehicle driver needs to be reminded of faults, and the hydraulic sensor needs to be replaced in time. According to the embodiment of the invention, the hydraulic sensor is arranged in one of the four wheel cylinders of the automobile, so that the hardware equipment of three sensors is saved, the installation space is saved, the problem of a hardware redundancy scheme is solved, the use cost is reduced, and the safety function requirement of the system is improved.
Optionally, calculating the outlet flow of the high-speed switch valve according to the duty ratio of the pulse width modulation signal and the pressure difference between two ends of the high-speed switch valve is determined based on the following formula:
wherein τ is the pulse width modulation signal duty ratio of the high-speed switch valve, and Q is the outlet flow of the high-speed switch valve; c (C) d Is the flow coefficient; a is the flow area of a throttle orifice of the high-speed switching valve; Δp is the pressure difference across the high-speed switch valve; ρ is the hydraulic oil density; χ is the orifice wet circumference length; η is the brake fluid dynamic viscosity; lambda (lambda) c Is a critical reynolds number.
Optionally, calculating the brake fluid volume change value according to the high-speed switch valve outlet flow meter includes:
and calculating a brake fluid volume change value according to the outlet flow of the high-speed switch valve and the time interval of the duty ratio of the twice pulse width modulation signals.
Specifically, the brake fluid volume change value can be calculated by integrating the outlet flow of the high-speed switch valve. The integration interval is a time interval of the duty ratio of the twice pulse width modulation signal.
FIG. 3 is a flow chart of another method for estimating the wheel cylinder pressure of a hydraulic brake system according to an embodiment of the present invention, and optionally, referring to FIG. 3, the high-speed switching valve includes a pressure increasing valve and a pressure decreasing valve; calculating the outlet flow of the high-speed switch valve according to the duty ratio of the pulse width modulation signal and the pressure difference between two ends of the high-speed switch valve, comprising:
calculating the liquid flow flowing into the hydraulic system according to the pulse width modulation signal duty ratio (1) of the booster valve and the pressure difference at two ends of the booster valve;
or calculating the liquid flow out of the liquid pressure system according to the pulse width modulation signal duty ratio (2) of the pressure reducing valve and the pressure difference between two ends of the pressure reducing valve.
Specifically, when the pressure-increasing valve of the hydraulic braking system is opened, the controller calculates the pulse width modulation signal duty ratio (1) of the pressure-increasing valve according to the expected wheel cylinder pressure and the current actual wheel cylinder pressure, calculates the pressure difference between the two ends of the pressure-increasing valve according to the master cylinder pressure and the estimated pressure of the previous period, substitutes the calculated pulse width modulation signal duty ratio (1) of the pressure-increasing valve and the pressure difference between the two ends of the pressure-increasing valve into the step S130, and calculates the input flow Q of the pressure-increasing valve in Calculating a brake fluid volume increasing value according to the step S140, calculating the current brake fluid volume according to the brake fluid volume in the wheel cylinder of the previous cycle, determining a current wheel cylinder pressure estimated value according to a relation curve of the brake fluid pressure and the brake fluid volume according to the current brake fluid volume inquiry, and taking the current wheel cylinder pressure estimated value as the previous cycle estimated pressure of the next calculation cycle to continue to participate in circulation;
when the pressure reducing valve of the hydraulic brake system is opened, the controller calculates the pulse width modulation signal duty ratio of the pressure reducing valve according to the expected wheel cylinder pressure and the current actual wheel cylinder pressure(2) Calculating the pressure difference between two ends of the pressure reducing valve according to the master cylinder pressure and the previous cycle estimated pressure, substituting the calculated pulse width modulation signal duty ratio (2) of the pressure reducing valve and the pressure difference between two ends of the pressure reducing valve into the step S130, and calculating the input flow Q of the pressure reducing valve out And then calculating a brake fluid volume reduction value according to the step S140, calculating the current brake fluid volume according to the brake fluid volume in the wheel cylinder of the previous cycle, finally determining the current wheel cylinder pressure estimated value according to the relation curve of the brake fluid pressure and the brake fluid volume of the current brake fluid volume inquiry, and taking the current wheel cylinder pressure estimated value as the previous cycle estimated pressure of the next calculation cycle to continue to participate in circulation.
An embodiment of the present invention provides a wheel cylinder pressure estimation device of a hydraulic brake system, and fig. 4 is a schematic structural diagram of the wheel cylinder pressure estimation device of the hydraulic brake system according to an embodiment of the present invention, and referring to fig. 4, a wheel cylinder pressure estimation device 300 includes:
a duty cycle acquisition module 310, configured to acquire a pulse width modulation signal duty cycle of the high-speed switch valve;
the pressure difference calculation module 320 is configured to calculate a pressure difference between two ends of the high-speed switch valve according to the master cylinder pressure and the estimated pressure of the previous cycle;
the outlet flow calculation module 330 is configured to calculate the outlet flow of the high-speed switch valve according to the duty cycle of the pwm signal and the pressure difference between two ends of the high-speed switch valve;
the volume calculating module 340 is configured to calculate a brake fluid volume change value according to the high-speed switch valve outlet flowmeter;
the current pressure determining module 350 is configured to calculate a current brake fluid volume according to the brake fluid volume change value and a brake fluid volume in a wheel cylinder of a previous cycle, and determine a current wheel cylinder pressure estimated value according to a relationship curve between brake fluid pressure and brake fluid volume and the current brake fluid volume; and the relation curve of the brake fluid pressure and the brake fluid volume is updated according to a preset period through a data analysis platform.
Further, the current pressure determination module 350 includes:
the relation curve determining unit is specifically configured to send a wheel cylinder pressure, a brake fluid volume, a brake state, a high-speed electromagnetic valve state, a wheel speed signal, a vehicle speed signal, an occurrence time and an environmental temperature to the data analysis platform according to a preset period, so as to calculate an updated relation curve of the brake fluid pressure and the brake fluid volume according to the wheel cylinder pressure, the brake fluid volume, the brake state, the high-speed electromagnetic valve state, the wheel speed signal, the vehicle speed signal, the occurrence time and the environmental temperature through the data analysis platform.
Further, a hydraulic pressure sensor is installed in one of four wheel cylinders of the automobile, and the hydraulic pressure sensor is used for detecting the pressure of the wheel cylinder; the current pressure determination module 350 further includes:
and the fault monitoring module is used for performing redundant comparison on the current wheel cylinder pressure estimated value and the wheel cylinder pressure detected by the hydraulic sensor after determining the current wheel cylinder pressure estimated value according to the relation curve of the brake fluid pressure and the brake fluid volume and the current brake fluid volume so as to judge whether the current wheel cylinder pressure estimated value is accurate and whether the hydraulic sensor fails.
Further, the outlet flow of the high-speed switch valve is calculated according to the duty ratio of the pulse width modulation signal and the pressure difference between two ends of the high-speed switch valve, and is determined based on the following formula:
wherein τ is the pulse width modulation signal duty ratio of the high-speed switch valve, and Q is the outlet flow of the high-speed switch valve; c (C) d Is the flow coefficient; a is the flow area of a throttle orifice of the high-speed switching valve; Δp is the pressure difference across the high-speed switch valve; ρ is the hydraulic oil density; χ is the orifice wet circumference length; η is the brake fluid dynamic viscosity; lambda (lambda) c Is a critical reynolds number.
Further, the volume calculation module 340 includes:
and the volume calculating unit is used for calculating the brake fluid volume change value according to the outlet flow of the high-speed switch valve and the time interval of the duty ratio of the twice pulse width modulation signal.
Further, the high-speed switching valve comprises a pressure increasing valve and a pressure reducing valve; the duty cycle acquisition module 310 includes:
the supercharging valve duty ratio acquisition subunit is used for calculating the liquid flow flowing into the hydraulic system according to the pulse width modulation signal duty ratio of the supercharging valve and the pressure difference at two ends of the supercharging valve;
the pressure reducing valve duty ratio obtaining subunit is used for calculating the liquid flow out of the liquid pressure system according to the pulse width modulation signal duty ratio of the pressure reducing valve and the pressure difference at the two ends of the pressure reducing valve.
The wheel cylinder pressure estimation device of the hydraulic braking system provided by the embodiment of the invention can execute the wheel cylinder pressure estimation method of the hydraulic braking system provided by any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the execution method.
An embodiment of the present invention provides an automotive hydraulic brake system, fig. 5 is a structural schematic diagram of the hydraulic system provided according to the embodiment of the present invention, and referring to fig. 5, the automotive hydraulic brake system includes a controller 11 and a hydraulic system 12; the hydraulic system 12 is used for providing wheel cylinder braking pressure, and the controller 11 is used for controlling the wheel cylinder braking pressure of the hydraulic system 12;
wherein the controller 11 includes the wheel cylinder pressure estimation device of the hydraulic brake system described in the above embodiment; the controller 11 is connected with the data analysis platform 20; the data analysis platform 20 is used for providing the updated brake fluid pressure and brake fluid volume relation curve to the controller according to a preset period.
Specifically, a hydraulic sensor a is installed in one of four wheel cylinders of the hydraulic system 12, the controller 11 calculates and processes data such as wheel cylinder pressure 1, brake fluid volume 2, brake state 3, high-speed electromagnetic valve state 4, wheel speed signal 5, vehicle speed signal 6, generation time 7, ambient temperature 8 and the like acquired by the hydraulic sensor a in real time to obtain the current brake fluid volume, and determines the current wheel cylinder pressure estimated value according to a relation curve of brake fluid pressure and brake fluid volume in the controller, at the moment, the controller 11 controls the opening or closing of a pressure increasing valve or a pressure reducing valve in the hydraulic system 12 to enable brake fluid to enter the wheel cylinder or take out the wheel cylinder, and further drives a piston to move, so that a brake caliper generates braking force to the wheel cylinder.
Meanwhile, the controller 11 at least needs to have an ethernet communication function, data such as the wheel cylinder pressure 1, the brake fluid volume 2, the brake state 3, the high-speed electromagnetic valve state 4, the wheel speed signal 5, the vehicle speed signal 6, the generation time 7, the ambient temperature 8 and the like acquired by the hydraulic sensor a are transmitted to the data analysis platform 20, the data analysis platform 20 integrates the data, performs data mining and data analysis, supplements and perfects a data sparse area of a relation curve of the original brake fluid pressure and the brake fluid volume, calculates an updated relation curve of the brake fluid pressure and the brake fluid volume, and transmits the updated relation curve of the brake fluid pressure and the brake fluid volume back to the controller 11 for estimating the wheel cylinder pressure.
Optionally, the controller 11 includes an ECU control unit, an ABS control unit, an ESC control unit, an ESP control unit, or an one_box control unit.
Fig. 6 shows a schematic diagram of an electronic device that may be used to implement an embodiment of the invention. Electronic devices are intended to represent various forms of digital computers, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. Electronic equipment may also represent various forms of mobile devices, such as personal digital processing, cellular telephones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions, are meant to be exemplary only, and are not meant to limit implementations of the inventions described and/or claimed herein.
As shown in fig. 6, the electronic device 510 includes at least one processor 511, and a memory communicatively connected to the at least one processor 511, such as a Read Only Memory (ROM) 512, a Random Access Memory (RAM) 513, etc., in which the memory stores computer programs executable by the at least one processor, and the processor 511 may perform various suitable actions and processes according to the computer programs stored in the Read Only Memory (ROM) 512 or the computer programs loaded from the storage unit 518 into the Random Access Memory (RAM) 513. In the RAM 513, various programs and data required for the operation of the electronic device 510 can also be stored. The processor 511, the ROM512, and the RAM 513 are connected to each other by a bus 514. An input/output (I/O) interface 515 is also connected to bus 514.
Various components in the electronic device 510 are connected to the I/O interface 515, including: an input unit 516 such as a keyboard, a mouse, etc.; an output unit 517 such as various types of displays, speakers, and the like; a storage unit 518 such as a magnetic disk, optical disk, etc.; and a communication unit 519 such as a network card, modem, wireless communication transceiver, or the like. The communication unit 519 allows the electronic device 510 to exchange information/data with other devices via a computer network, such as the internet, and/or various telecommunications networks.
The processor 511 may be a variety of general and/or special purpose processing components with processing and computing capabilities. Some examples of processor 511 include, but are not limited to, a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), various specialized Artificial Intelligence (AI) computing chips, various processors running machine learning model algorithms, digital Signal Processors (DSPs), and any suitable processor, controller, microcontroller, etc. The processor 511 performs the various methods and processes described above, such as wheel cylinder pressure estimation of the hydraulic brake system.
In some embodiments, the wheel cylinder pressure estimation of the hydraulic brake system may be implemented as a computer program tangibly embodied on a computer-readable storage medium, such as the storage unit 518. In some embodiments, some or all of the computer program may be loaded and/or installed onto the electronic device 510 via the ROM512 and/or the communication unit 519. When the computer program is loaded into the RAM 513 and executed by the processor 511, one or more steps of the wheel cylinder pressure estimation of the hydraulic brake system described above may be performed. Alternatively, in other embodiments, the processor 511 may be configured to perform wheel cylinder pressure estimation of the hydraulic brake system in any other suitable manner (e.g., by means of firmware).
Various implementations of the systems and techniques described here above may be implemented in digital electronic circuitry, integrated circuit systems, field Programmable Gate Arrays (FPGAs), application Specific Integrated Circuits (ASICs), application Specific Standard Products (ASSPs), systems On Chip (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and/or combinations thereof. These various embodiments may include: implemented in one or more computer programs, the one or more computer programs may be executed and/or interpreted on a programmable system including at least one programmable processor, which may be a special purpose or general-purpose programmable processor, that may receive data and instructions from, and transmit data and instructions to, a storage system, at least one input device, and at least one output device.
A computer program for carrying out methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the computer programs, when executed by the processor, cause the functions/acts specified in the flowchart and/or block diagram block or blocks to be implemented. The computer program may execute entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.
In the context of the present invention, a computer-readable storage medium may be a tangible medium that can contain, or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer readable storage medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Alternatively, the computer readable storage medium may be a machine readable signal medium. More specific examples of a machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.
To provide for interaction with a user, the systems and techniques described here can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to a user; and a keyboard and a pointing device (e.g., a mouse or a trackball) through which a user can provide input to the electronic device. Other kinds of devices may also be used to provide for interaction with a user; for example, feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form, including acoustic input, speech input, or tactile input.
The systems and techniques described here can be implemented in a computing system that includes a background component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front-end component (e.g., a user computer having a graphical user interface or a web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such background, middleware, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: local Area Networks (LANs), wide Area Networks (WANs), blockchain networks, and the internet.
The computing system may include clients and servers. The client and server are typically remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. The server can be a cloud server, also called a cloud computing server or a cloud host, and is a host product in a cloud computing service system, so that the defects of high management difficulty and weak service expansibility in the traditional physical hosts and VPS service are overcome.
It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps described in the present invention may be performed in parallel, sequentially, or in a different order, so long as the desired results of the technical solution of the present invention are achieved, and the present invention is not limited herein.
The above embodiments do not limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.
Claims (10)
1. A wheel cylinder pressure estimation method of a hydraulic brake system, characterized by comprising:
acquiring the pulse width modulation signal duty ratio of a high-speed switch valve;
calculating the pressure difference of two ends of the high-speed switch valve according to the master cylinder pressure and the estimated pressure of the previous period;
calculating the outlet flow of the high-speed switch valve according to the duty ratio of the pulse width modulation signal and the pressure difference between two ends of the high-speed switch valve;
calculating a brake fluid volume change value according to the high-speed switch valve outlet flowmeter;
calculating the current brake fluid volume according to the brake fluid volume change value and the brake fluid volume in the wheel cylinder of the previous cycle, and determining the current wheel cylinder pressure estimated value according to the relation curve of the brake fluid pressure and the brake fluid volume and the current brake fluid volume; and the relation curve of the brake fluid pressure and the brake fluid volume is updated according to a preset period through a data analysis platform.
2. The method for estimating the wheel cylinder pressure of the hydraulic brake system according to claim 1, characterized by updating the relation between the brake fluid pressure and the brake fluid volume in a preset cycle by the data analysis platform, comprising:
and sending wheel cylinder pressure, brake fluid volume, brake state, high-speed electromagnetic valve state, wheel speed signal, vehicle speed signal, occurrence time and environmental temperature to the data analysis platform according to a preset period, so that an updated relation curve of the brake fluid pressure and the brake fluid volume is calculated by the data analysis platform according to the wheel cylinder pressure, the brake fluid volume, the brake state, the high-speed electromagnetic valve state, the wheel speed signal, the vehicle speed signal, the occurrence time and the environmental temperature.
3. The wheel cylinder pressure estimation method of a hydraulic brake system according to claim 2, characterized in that a hydraulic pressure sensor for detecting the wheel cylinder pressure is installed in one of four wheel cylinders of an automobile; after determining the current wheel cylinder pressure estimated value according to the relation curve between the brake fluid pressure and the brake fluid volume and the current brake fluid volume, the method further comprises the following steps:
and performing redundant comparison on the current wheel cylinder pressure estimated value and the wheel cylinder pressure detected by the hydraulic pressure sensor to judge whether the current wheel cylinder pressure estimated value is accurate or not and whether the hydraulic pressure sensor fails or not.
4. The method for estimating the wheel cylinder pressure of the hydraulic brake system according to claim 1, characterized in that the calculation of the high-speed switch valve outlet flow rate from the pulse width modulation signal duty ratio and the pressure difference across the high-speed switch valve is determined based on the following formula:
wherein τ is the pulse width modulation signal duty ratio of the high-speed switch valve, and Q is the outlet flow of the high-speed switch valve; c (C) d Is the flow coefficient; a is the flow area of a throttle orifice of the high-speed switching valve; Δp is the pressure difference across the high-speed switch valve; ρ is the hydraulic oil density; χ is the orifice wet circumference length; η is the brake fluid dynamic viscosity; lambda (lambda) c Is a critical reynolds number.
5. The method for estimating the wheel cylinder pressure of the hydraulic brake system according to claim 1, characterized in that the calculating the brake fluid volume change value from the high-speed switching valve outlet flow meter includes:
and calculating a brake fluid volume change value according to the outlet flow of the high-speed switching valve and the time interval of the duty ratio of the twice pulse width modulation signal.
6. The wheel cylinder pressure estimation method of a hydraulic brake system according to claim 1, characterized in that the high-speed switching valve includes a pressure increasing valve and a pressure reducing valve; the calculating the outlet flow of the high-speed switch valve according to the duty ratio of the pulse width modulation signal and the pressure difference at two ends of the high-speed switch valve comprises the following steps:
calculating the liquid flow flowing into a hydraulic system according to the pulse width modulation signal duty ratio of the booster valve and the pressure difference at two ends of the booster valve;
or, calculating the liquid flow out of the hydraulic system according to the pulse width modulation signal duty ratio of the pressure reducing valve and the pressure difference between two ends of the pressure reducing valve.
7. A wheel cylinder pressure estimation device of a hydraulic brake system, characterized by comprising:
the duty cycle acquisition module is used for acquiring the duty cycle of the pulse width modulation signal of the high-speed switch valve;
the pressure difference calculation module is used for calculating the pressure difference of the two ends of the high-speed switch valve according to the master cylinder pressure and the estimated pressure of the previous period;
the outlet flow calculation module is used for calculating the outlet flow of the high-speed switch valve according to the duty ratio of the pulse width modulation signal and the pressure difference at the two ends of the high-speed switch valve;
the volume calculation module is used for calculating a brake fluid volume change value according to the high-speed switch valve outlet flowmeter;
the current pressure determining module is used for calculating the current brake fluid volume according to the brake fluid volume change value and the brake fluid volume in the wheel cylinder of the previous cycle, and determining the current wheel cylinder pressure estimated value according to the relation curve of the brake fluid pressure and the brake fluid volume and the current brake fluid volume; and the relation curve of the brake fluid pressure and the brake fluid volume is updated according to a preset period through a data center analysis platform.
8. The hydraulic brake system of the automobile is characterized by comprising a controller and a hydraulic system; the hydraulic system is used for providing wheel cylinder braking pressure, and the controller is used for controlling the wheel cylinder braking pressure of the hydraulic system;
wherein the controller includes the wheel cylinder pressure estimation device of the hydraulic brake system according to claim 7; the controller is connected with the data analysis platform; the data analysis platform is used for providing updated relation curves of brake fluid pressure and brake fluid volume for the controller according to a preset period.
9. The automotive hydraulic brake system of claim 8, wherein the controller comprises an ECU control unit, an ABS control unit, an ESC control unit, an ESP control unit, or an ONE BOX control unit.
10. An electronic device, the electronic device comprising:
at least one processor; and
a memory communicatively coupled to the at least one processor; wherein,
the memory stores a computer program executable by the at least one processor to enable the at least one processor to perform the wheel cylinder pressure estimation method of the hydraulic brake system according to any one of claims 1 to 6.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311147124.8A CN117033861A (en) | 2023-09-06 | 2023-09-06 | Wheel cylinder pressure estimation method and device for hydraulic braking system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311147124.8A CN117033861A (en) | 2023-09-06 | 2023-09-06 | Wheel cylinder pressure estimation method and device for hydraulic braking system |
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| CN117033861A true CN117033861A (en) | 2023-11-10 |
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| CN202311147124.8A Pending CN117033861A (en) | 2023-09-06 | 2023-09-06 | Wheel cylinder pressure estimation method and device for hydraulic braking system |
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| CN (1) | CN117033861A (en) |
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