CN117485300A - Parking brake reclock control method, parking brake system and automobile - Google Patents

Parking brake reclock control method, parking brake system and automobile Download PDF

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Publication number
CN117485300A
CN117485300A CN202311330759.1A CN202311330759A CN117485300A CN 117485300 A CN117485300 A CN 117485300A CN 202311330759 A CN202311330759 A CN 202311330759A CN 117485300 A CN117485300 A CN 117485300A
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CN
China
Prior art keywords
clamping
brake
temperature
brake disc
parking
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202311330759.1A
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Chinese (zh)
Inventor
耿星
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Shanghai Liqun Technology Co ltd
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Shanghai Liqun Technology Co ltd
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Publication date
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Priority to CN202311330759.1A priority Critical patent/CN117485300A/en
Publication of CN117485300A publication Critical patent/CN117485300A/en
Pending legal-status Critical Current

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Classifications

    • 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
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/172—Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters
    • 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
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/24—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to vehicle inclination or change of direction, e.g. negotiating bends
    • B60T8/245—Longitudinal vehicle inclination
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Regulating Braking Force (AREA)

Abstract

The invention discloses a parking brake re-clamping control method, which comprises the following steps: s1, detecting whether the vehicle is in a running state currently, if so, executing a step S2, and if so, executing a step S3; s2, updating an environment coefficient χ based on a recursive least square method; s3, entering a re-clamping mode, determining the current clamping force and the temperature of the brake disc based on the environmental coefficient χ at the current moment, and determining the temperature T of the brake disc based on the current temperature T of the brake disc n A re-pinch policy is determined. According to the invention, the environment coefficient is learned online, when the vehicle is parked, the current learned environment coefficient is used for calculating the clamping force under the high-temperature re-clamping, so that the temperature of the brake disc is obtained, the re-clamping time and the re-clamping frequency are adapted based on the temperature, the high-temperature re-clamping effect is improved, the safety of the vehicle and the service life of the parking brake system are improved.

Description

Parking brake reclock control method, parking brake system and automobile
Technical Field
The invention belongs to the technical field of braking, and particularly relates to a parking brake re-clamping control method, a parking brake system and an automobile.
Background
The automobile driving road surface condition is complicated, and the driver needs to often use the manual brake to park, release parking etc. and the hill start failure can cause accidents such as engine flameout, car sliding, etc. Meanwhile, the driver forgets to pull the handle to brake when parking, and the dangerous situations such as sliding and the like can be caused due to insufficient clamping force of the hand brake. For this reason, electronic parking brake systems have been developed. The hand brake device uses the toggle switch to replace the traditional hand brake, optimizes the space in the vehicle, and has high safety and reliability.
With the application of more and more electronic control products to automobiles, the risk of automobile safety accidents is increased, and the running safety becomes a hot spot gradually along with the increase of the speed per hour, so that the reliability of a braking system is more and more important. The service brake system comprises a service brake and a parking brake, which are commonly referred to as a foot brake and a hand brake, and the excellent performance of the service brake system is critical to the safety of the service.
After a long period of travel of the vehicle, the brake disc may expand due to a temperature rise, and if the vehicle is now just parked on a slope, the braking force of the brake disc is small relative to that when cooling, at which time there is a risk of slipping.
Disclosure of Invention
The present invention provides a parking brake re-clamping control method, which aims to improve the above problems.
The invention is realized in such a way that a parking brake re-clamping control method comprises the following steps:
s1, detecting whether the vehicle is in a running state currently, if so, executing a step S2, and if so, executing a step S3;
s2, updating an environment coefficient χ based on a recursive least square method;
s3, entering a re-clamping mode, determining the current clamping force and the temperature of the brake disc based on the environmental coefficient χ at the current moment, and determining the temperature T of the brake disc based on the current temperature T of the brake disc n A re-pinch policy is determined.
Further, the calculation formula of the environmental coefficient χ is specifically as follows:
wherein c represents the specific heat capacity of the brake disc, m represents the mass of the brake disc, f represents the friction factor of the brake disc, deltaT is the temperature rise of the brake disc during braking, and T e 、t s The time of braking end and the time of braking start respectively, k is the diffusion coefficient, C is the ambient temperature, d represents the piston diameter of the brakeMu represents the friction factor of the ground, V w Represents wheel speed, g represents gravitational acceleration, M is the mass of the whole vehicle, and alpha v Representing the tilt angle of the vehicle.
Further, the clamping force F expression is specifically as follows:
wherein g represents gravity acceleration, M is the mass of the whole vehicle, and alpha v The inclination angle of the vehicle is represented by R, the tire radius is represented by f, the friction factor of the brake disc is represented by R, and the brake drum radius is represented by R.
Further, the current temperature T of the brake disc n The calculation formula is specifically as follows:
wherein t is e 、t s The time of braking end and the time of braking start are respectively shown as d represents the piston diameter of the brake, F represents the clamping force, mu represents the friction factor of the ground, r represents the radius of the brake drum and V w The wheel speed is represented by C, the ambient temperature is represented by C, the specific heat capacity of the brake disc is represented by m, the mass of the brake disc is represented by m, and the tire radius is represented by R.
Further, the time and the number of re-clamping are determined based on the current temperature of the brake disc, and the higher the temperature of the brake disc is, the shorter the first re-clamping time is, and the number of re-clamping times is increased.
Further, the reclock strategy is specifically as follows:
when T is n Less than 300 ℃, no reclamping operation is performed;
when the temperature is 300 ℃ to less than or equal to T n Performing 1 reclassification after 180 seconds of parking at < 400 ℃;
when the temperature is 400 ℃ to be less than or equal to T n 1 re-clamping is performed after 120 seconds of parking at the temperature of less than 500 ℃, and 2 nd re-clamping is performed after 300 seconds;
when T is n More than or equal to 500 ℃, 1 re-clamping is performed after 90 seconds of parking, 2 nd re-clamping is performed after 210 seconds, and 600 seconds of re-clamping is performedLine 3 reclassifying.
Further, at the parking time t p And after the time threshold value is larger than the set time threshold value, automatically exiting the re-clamping mode.
The present invention is achieved by an electronic parking brake system comprising:
the control unit controls the re-clamping of the braking mechanism based on the parking re-clamping control method when the vehicle is in a parking state.
The invention is realized in that an automobile is provided with the electronic parking brake system integrated on the automobile.
According to the invention, the environment coefficient is learned online, when the vehicle is parked, the current learned environment coefficient is used for calculating the clamping force under the high-temperature re-clamping, so that the temperature of the brake disc is obtained, the re-clamping time and the re-clamping frequency are adapted based on the temperature, the high-temperature re-clamping effect is improved, the safety of the vehicle and the service life of the parking brake system are improved.
Drawings
Fig. 1 is a flowchart of a high-temperature brake re-clamping control method according to an embodiment of the present invention.
Detailed Description
The following detailed description of the embodiments of the invention, given by way of example only, is presented in the accompanying drawings to aid in a more complete, accurate, and thorough understanding of the inventive concepts and aspects of the invention by those skilled in the art.
Fig. 1 is a flowchart of a parking brake re-clamping control method according to an embodiment of the present invention, where the method includes the following steps:
s1, detecting whether the vehicle is in a running state currently, if so, executing a step S2, and if so, executing a step S3;
s2, updating an environment coefficient χ based on a recursive least square method;
s3, entering a re-clamping mode, and determining the clamping force based on an environmental coefficient χ at the current momentBrake disc temperature T n Based on the temperature T of the current brake disc n A re-pinch policy is determined.
In the running process of the vehicle, a driver intermittently takes braking measures according to road conditions and vehicle speeds, and energy transfer exists in each braking, namely, the kinetic energy of the vehicle is converted into the heat energy of a brake disc, and the energy E transferred in each pedal braking has the following calculation formula:
wherein a represents energy transfer efficiency, M is the mass of the whole vehicle, and V s 、V e The vehicle speed before braking and the vehicle speed after braking are respectively indicated.
Because most of heat energy is absorbed by brake system components such as a brake disc and the like, the temperature of the brake disc and the like rises, and the temperature rising quantity delta T meets the following conditions:
E＝cmΔT (2)
where c represents the specific heat capacity of the brake disc, m represents the mass of the brake disc, and Δt represents the amount of temperature rise of the brake disc due to braking.
As can be seen from the above equation (1) and equation (2), the temperature increase Δt of the brake disc at the time of braking is expressed as follows:
the temperature rise delta T of the brake disc is corrected in consideration of the air radiation of the brake disc, and the corrected temperature rise delta T of the brake disc is used 1 The calculation formula is specifically as follows:
ΔT 1 ＝ΔT-k(ΔT-C)(t e -t s ) (4)
the temperature rise Δt of the brake disc during braking is far greater than the ambient temperature C, k is the diffusion coefficient, T e 、t s The time when the braking is finished and the time when the braking is started are respectively indicated, and C is the ambient temperature.
According to the basis ofPressure braking model, brake disc temperature rise delta T 1 The calculation formula is as follows:
wherein F represents the clamping force, d represents the piston diameter of the brake, mu represents the friction factor of the ground, r represents the radius of the brake drum, V w Representing wheel speed;
since the clamping force is influenced by the environment, an environment coefficient χ is introduced, and the clamping force F at this time is expressed as follows:
wherein g represents gravity acceleration, M is the mass of the whole vehicle, and alpha v The inclination angle of the vehicle is represented by R, the tire radius is represented by f, the friction factor of the brake disc is represented by R, and the brake drum radius is represented by R.
The expression of the environmental coefficient χ is specifically as follows in combination of the formula (4), the formula (5) and the formula (6):
and updating the environment coefficient χ by adopting a recursive least square method, so as to realize the online identification of the environment coefficient χ.
When the vehicle is detected to be in a parking state, a current environmental coefficient χ is obtained, a current braking force is calculated based on a formula (6), and then a current temperature T of a current brake disc is obtained n The calculation formula is specifically as follows:
acquiring the current temperature T of the brake disc based on formula (8) n Thereafter, based on temperature T n Determining a re-clamping strategy, wherein the re-clamping strategy of the invention is as follows：
The time and the number of re-clamping are determined based on the current temperature of the brake disc, the higher the temperature of the brake disc is, the shorter the first re-clamping time is, and the number of re-clamping is increased, and a specific re-clamping strategy based on the temperature of the brake disc is given below, wherein the strategy is as follows:
when T is n Less than 300 ℃, no reclamping operation is performed; when the temperature is 300 ℃ to less than or equal to T n Performing 1 reclassification after 180 seconds of parking at < 400 ℃; when the temperature is 400 ℃ to be less than or equal to T n 1 re-clamping is performed after 120 seconds of parking at the temperature of less than 500 ℃, and 2 nd re-clamping is performed after 300 seconds; when T is n 1 re-clamping is performed after 90 seconds of parking, 2 nd re-clamping is performed after 210 seconds, and 3 rd re-clamping is performed after 600 seconds; at the parking time t p And automatically exiting the re-clamping mode after more than 1800 s.
The embodiment of the invention also provides an electronic parking brake system, which comprises:
the control unit controls the re-clamping of the braking mechanism in parking based on the parking re-clamping control method.
The embodiment of the invention also provides an automobile, and the electronic parking brake system is integrated on the automobile.
According to the invention, the environment coefficient is learned online, when the vehicle is parked, the current learned environment coefficient is used for calculating the clamping force under the high-temperature re-clamping, so that the temperature of the brake disc is obtained, the re-clamping time and the re-clamping frequency are adapted based on the temperature, the high-temperature re-clamping effect is improved, the safety of the vehicle and the service life of the parking brake system are improved.
While the present invention has been described by way of example, it should be apparent that the practice of the invention is not limited by the foregoing, but rather is intended to cover various insubstantial modifications of the method concepts and teachings of the invention, either as applied to other applications without modification, or as applied directly to other applications, without departing from the scope of the invention.

Claims (9)

1. A parking brake override control method, the method comprising the steps of:
s1, detecting whether the vehicle is in a running state currently, if so, executing a step S2, and if so, executing a step S3;
s2, updating an environment coefficient χ based on a recursive least square method;
s3, entering a re-clamping mode, determining the current clamping force and the temperature of the brake disc based on the environmental coefficient χ at the current moment, and determining the temperature T of the brake disc based on the current temperature T of the brake disc n A re-pinch policy is determined.
2. The parking brake re-clamping control method according to claim 1, wherein the calculation formula of the environmental coefficient χ is specifically as follows:
wherein c represents the specific heat capacity of the brake disc, m represents the mass of the brake disc, f represents the friction factor of the brake disc, deltaT is the temperature rise of the brake disc during braking, and T e 、t s The time of braking is finished and the time of braking is started respectively, k is a diffusion coefficient, C is an ambient temperature, d is a piston diameter of the brake, mu is a friction factor of the ground, and V w Represents wheel speed, g represents gravitational acceleration, M is the mass of the whole vehicle, and alpha v Representing the tilt angle of the vehicle.
3. The parking brake re-clamping control method as set forth in claim 1, wherein the clamping force F expression is specifically as follows:
wherein g represents gravity acceleration, M is the mass of the whole vehicle, and alpha v The vehicle inclination angle is represented by R, the tire radius is represented by f, the friction factor of the brake disc is represented by f, and the brake drum radius is represented by R.
4. The parking brake re-clamping control method according to claim 1, characterized in that the current temperature T of the brake disc n The calculation formula is specifically as follows:
wherein t is e 、t s The time of braking end and the time of braking start are respectively shown as d represents the piston diameter of the brake, F represents the clamping force, mu represents the friction factor of the ground, r represents the radius of the brake drum and V w The wheel speed is represented by C, the ambient temperature is represented by C, the specific heat capacity of the brake disc is represented by m, the mass of the brake disc is represented by m, and the tire radius is represented by R.
5. The parking brake re-clamping control method according to claim 1, wherein the re-clamping timing and the number of re-clamping times are determined based on the current temperature of the brake disc, and the higher the temperature of the brake disc, the shorter the first re-clamping time and the number of re-clamping times increases.
6. The parking brake override method of claim 5, wherein the override strategy is as follows:
when T is n Less than 300 ℃, no reclamping operation is performed;
when the temperature is 300 ℃ to less than or equal to T n Performing 1 reclassification after 180 seconds of parking at < 400 ℃;
when the temperature is 400 ℃ to be less than or equal to T n 1 re-clamping is performed after 120 seconds of parking at the temperature of less than 500 ℃, and 2 nd re-clamping is performed after 300 seconds;
when T is n And (3) 1 time of re-clamping is performed after the vehicle is parked for 90 seconds, 2 times of re-clamping is performed after 210 seconds, and 3 times of re-clamping is performed after 600 seconds.
7. The parking brake override control method of claim 1, wherein at a parking time t p And after the time threshold value is larger than the set time threshold value, automatically exiting the re-clamping mode.
8. An electronic parking brake system, comprising:
a brake mechanism including a brake disc, and a control unit for controlling the brake mechanism, the control unit controlling re-clamping of the brake mechanism based on the parking re-clamping control method according to any one of claims 1 to 7 when the vehicle is in a parking state.
9. An automobile having integrated thereon the electronic parking brake system of claim 8.
CN202311330759.1A 2023-10-13 2023-10-13 Parking brake reclock control method, parking brake system and automobile Pending CN117485300A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202311330759.1A CN117485300A (en) 2023-10-13 2023-10-13 Parking brake reclock control method, parking brake system and automobile

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311330759.1A CN117485300A (en) 2023-10-13 2023-10-13 Parking brake reclock control method, parking brake system and automobile

Publications (1)

Publication Number Publication Date
CN117485300A true CN117485300A (en) 2024-02-02

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ID=89673449

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202311330759.1A Pending CN117485300A (en) 2023-10-13 2023-10-13 Parking brake reclock control method, parking brake system and automobile

Country Status (1)

Country Link
CN (1) CN117485300A (en)

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