CN114407870B - Control method and device for electric composite braking system, storage medium and commercial vehicle - Google Patents

Control method and device for electric composite braking system, storage medium and commercial vehicle Download PDF

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Publication number
CN114407870B
CN114407870B CN202210046450.9A CN202210046450A CN114407870B CN 114407870 B CN114407870 B CN 114407870B CN 202210046450 A CN202210046450 A CN 202210046450A CN 114407870 B CN114407870 B CN 114407870B
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pressure
braking
target
brake
state
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CN114407870A (en
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龙元香
张俊智
何承坤
刘伟龙
黄万义
龙志能
冯小明
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Kormee Automotive Electronic Control Technology Co ltd
Tsinghua University
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Kormee Automotive Electronic Control Technology Co ltd
Tsinghua University
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/04—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units
    • B60W10/08—Conjoint control of vehicle sub-units of different type or different function including control of propulsion units including control of electric propulsion units, e.g. motors or generators
    • 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
    • B60T8/32—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 a speed condition, e.g. acceleration or deceleration
    • B60T8/321—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 a speed condition, e.g. acceleration or deceleration deceleration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/18—Conjoint control of vehicle sub-units of different type or different function including control of braking systems
    • B60W10/184—Conjoint control of vehicle sub-units of different type or different function including control of braking systems with wheel brakes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2710/00—Output or target parameters relating to a particular sub-units
    • B60W2710/08—Electric propulsion units
    • B60W2710/083—Torque
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2710/00—Output or target parameters relating to a particular sub-units
    • B60W2710/18—Braking system
    • B60W2710/182—Brake pressure, e.g. of fluid or between pad and disc
    • 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)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Mathematical Physics (AREA)
  • Regulating Braking Force (AREA)
  • Braking Systems And Boosters (AREA)

Abstract

The invention discloses a control method and device of an electric composite braking system, a storage medium and a commercial vehicle, and can be applied to the technical field of vehicles. According to the method, the required braking deceleration is determined according to the braking signal at the current moment, the required braking moment is determined according to the vehicle state data and the required braking deceleration at the current moment, so that the timeliness of the data is improved, the target motor braking moment of the vehicle is determined according to the rear axle required braking moment and the maximum motor braking moment, the working state of the motor is controlled according to the target motor braking moment, the target braking pressure of the vehicle is determined according to the front axle required braking moment, the rear axle required braking moment and the inverse model of the braking system, and the braking air chamber pressure is regulated according to the target braking pressure through the braking pressure regulating module, so that the response speed and the control precision of the electric composite braking system are improved.

Description

Control method and device for electric composite braking system, storage medium and commercial vehicle
Technical Field
The invention relates to the technical field of vehicles, in particular to a control method and device of an electric composite braking system, a storage medium and a commercial vehicle.
Background
In the related art, the development process of the electric and intelligent of the commercial vehicle provides new challenges for the performance upgrading and the function expansion of a braking system of the commercial vehicle. The motor feedback braking force participates in the whole vehicle dynamics control by the whole vehicle electrodynamic property, and the dynamic performance of the air pressure braking force needs to be further improved. The new functions of self-adaptive cruising, active collision avoidance and the like required by the whole vehicle intellectualization also provide higher technical requirements for the pressure response speed and the pressure regulation precision of the EBS. In the aspect of pressure regulation of a brake air chamber, an open-loop control mode is adopted at present, the controller is simple in structure, however, the pressure control precision is lower, the response speed is slower, and the robustness is poor.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a control method and device of an electric composite braking system, a storage medium and a commercial vehicle, and the control method and device can effectively improve the pressure control precision and response speed.
In one aspect, an embodiment of the present invention provides a control method of an electric composite brake system, including the following steps:
acquiring a braking signal and vehicle state data of a vehicle at the current moment;
determining a demanded braking deceleration from the braking signal;
determining a required braking moment according to the vehicle state data and the required braking deceleration, wherein the required braking moment comprises a front axle required braking moment and a rear axle required braking moment;
determining a target motor braking moment of the vehicle according to the rear axle required braking moment and the maximum motor braking moment;
controlling the working state of the motor according to the target motor braking torque;
determining a target braking pressure of the vehicle according to the front axle required braking moment, the rear axle required braking moment and a braking system inverse model, wherein the target braking pressure comprises a front axle target braking pressure and a rear axle target braking pressure;
and adjusting the pressure of the brake air chamber through a brake pressure adjusting module according to the target brake pressure.
In some embodiments, the adjusting the brake chamber pressure by the brake pressure adjustment module according to the target brake pressure includes:
acquiring the actual braking pressure of the braking air chamber;
adjusting the working state of the brake pressure adjusting module according to the target brake pressure and the actual brake pressure;
determining the duty ratio of a solenoid valve driving signal according to the working state of the brake pressure regulating module;
and regulating the pressure of the brake chamber according to the duty ratio.
In some embodiments, said adjusting the operating state of the brake pressure adjustment module according to the target brake pressure and the actual brake pressure comprises:
when the target braking pressure is equal to zero, adjusting the working state of the braking pressure adjusting module to enter a pressure maintaining state;
when the target braking pressure is greater than zero and a first preset condition is met, the working state of the braking pressure adjusting module is adjusted to enter a pressure maintaining state, wherein the meeting of the first preset condition comprises that the difference value between the target braking pressure and the actual braking pressure is smaller than or equal to a first threshold value;
when the target braking pressure is greater than zero and meets a second preset condition, adjusting the working state of the braking pressure adjusting module to enter a closed-loop supercharging state, wherein the second preset condition comprises that the difference value between the target braking pressure and the actual braking pressure is greater than a first threshold value and less than or equal to a second threshold value;
when the target braking pressure is greater than zero and a third preset condition is met, the working state of the braking pressure adjusting module is adjusted to enter an open-loop supercharging state, and the meeting of the third preset condition comprises that the difference value between the target braking pressure and the actual braking pressure is greater than a second threshold value;
when the target braking pressure is smaller than zero and a fourth preset condition is met, the working state of the braking pressure adjusting module is adjusted to enter a pressure maintaining state, and the fourth preset condition is met, wherein the difference value between the actual braking pressure and the target braking pressure is smaller than or equal to a first threshold value;
when the target braking pressure is smaller than zero and a fifth preset condition is met, the working state of the braking pressure adjusting module is adjusted to enter a closed-loop decompression state, and the fifth preset condition is met, wherein the difference value between the actual braking pressure and the target braking pressure is larger than a first threshold value and smaller than or equal to a second threshold value;
when the target braking pressure is smaller than zero and a sixth preset condition is met, the working state of the braking pressure adjusting module is adjusted to enter an open-loop decompression state, and the meeting of the sixth preset condition comprises that the difference value between the actual braking pressure and the target braking pressure is larger than a second threshold value;
wherein the first threshold value is smaller than the second threshold value.
In some embodiments, the brake pressure adjustment module includes a controller, a pressure increasing valve, a pressure reducing valve, a backup valve, and a barometric pressure sensor, all electrically connected to the controller.
In some embodiments, the determining the duty cycle of the solenoid drive signal according to the operating state of the brake pressure adjustment module includes:
when the working state of the brake pressure adjusting module is in a pressure maintaining state, determining that the duty ratio of the electromagnetic valve driving signal is equal to zero;
when the working state of the brake pressure regulating module is in a closed-loop supercharging state, determining that the duty ratio of the pressure reducing valve driving signal is equal to zero, and calculating the duty ratio of the supercharging valve driving signal through a duty ratio calculating module;
when the working state of the brake pressure regulating module is in an open-loop supercharging state, determining that the duty ratio of the pressure reducing valve driving signal is equal to zero, wherein the duty ratio of the supercharging valve driving signal is equal to one hundred;
when the working state of the brake pressure regulating module is in a closed-loop decompression state, calculating the duty ratio of the decompression valve driving signal through the duty ratio calculating module, and determining that the duty ratio of the supercharging valve driving signal is equal to zero;
when the working state of the brake pressure regulating module is in an open-loop decompression state, determining that the duty ratio of the decompression valve driving signal is equal to one hundred, and the duty ratio of the supercharging valve driving signal is equal to zero;
wherein the duty cycle of the solenoid valve drive signal includes the duty cycle of the pressure reducing valve drive signal and the duty cycle of the pressure increasing valve drive signal.
In some embodiments, the duty cycle calculation module includes a first tracking differentiator, a second tracking differentiator, and a nonlinear feedback controller;
the first tracking differentiator is used for transforming the target braking pressure and generating a first differentiated signal;
the second tracking differentiator is used for filtering the actual braking pressure and generating a second differentiated signal;
the nonlinear feedback controller is used for calculating the duty ratio of the driving signal of the pressure increasing valve or the pressure reducing valve according to the air source pressure signal, the first differential signal and the second differential signal sent by the controller.
In some embodiments, the vehicle state data includes road adhesion coefficient, mass of the vehicle, distance of a vehicle centroid to a front-rear axis, centroid height of the vehicle, speed of the vehicle at a current time, motor speed, and power battery state of charge.
In another aspect, an embodiment of the present invention provides a control device of an electric composite brake system, including:
at least one memory for storing a program;
at least one processor for loading the program to perform the method of controlling the electric compound brake system.
In another aspect, an embodiment of the present invention provides a storage medium in which a computer-executable program is stored, which when executed by a processor is configured to implement the control method of the electric compound brake system.
On the other hand, the embodiment of the invention provides a commercial vehicle, and the braking control is performed by the control method of the electric composite braking system.
The control method of the electric composite braking system provided by the embodiment of the invention has the following beneficial effects:
according to the embodiment, the required braking deceleration is determined according to the braking signal at the current moment, the required braking moment is determined according to the vehicle state data and the required braking deceleration at the current moment, so that the timeliness of the data is improved, the target motor braking moment of the vehicle is determined according to the rear axle required braking moment and the maximum motor braking moment, the working state of the motor is controlled according to the target motor braking moment, the target braking pressure of the vehicle is determined according to the front axle required braking moment, the rear axle required braking moment and the braking system inverse model, and the braking air chamber pressure is regulated according to the target braking pressure through the braking pressure regulating module, so that the response speed and the control accuracy of the electric composite braking system are improved.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
The invention is further described with reference to the accompanying drawings and examples, in which:
FIG. 1 is a flow chart of a method of controlling an electric compound brake system according to an embodiment of the present invention;
FIG. 2 is a flow chart illustrating the operation of the brake pressure adjustment module according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a brake pressure adjusting module according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a duty cycle calculation module according to an embodiment of the present invention;
fig. 5 is a data flow chart of the embodiment of the invention applied to a rear axle driven electric-only commercial vehicle.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.
In the description of the present invention, it should be understood that references to orientation descriptions such as upper, lower, front, rear, left, right, etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of description of the present invention and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.
In the description of the present invention, the meaning of a number is one or more, the meaning of a number is two or more, and greater than, less than, exceeding, etc. are understood to exclude the present number, and the meaning of a number is understood to include the present number. The description of the first and second is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present invention, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly and the specific meaning of the terms in the present invention can be reasonably determined by a person skilled in the art in combination with the specific contents of the technical scheme.
In the description of the present invention, the descriptions of the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Referring to fig. 1, an embodiment of the present invention provides a control method of an electric compound brake system, including but not limited to the following:
and 110, acquiring a braking signal and vehicle state data of the vehicle at the current moment. Wherein the brake signal may comprise a brake pedal displacement signal or a brake pedal force signal. The vehicle state data may include at least one of road adhesion coefficient, mass of the vehicle, distance of a vehicle centroid to a front-rear axis, centroid height of the vehicle, speed of the vehicle at a current time, motor speed, or state of charge of the power battery. These vehicle state data may be measured by onboard sensors or estimated by algorithms.
And 120, determining the required braking deceleration according to the braking signal.
And 130, determining a required braking moment according to the vehicle state data and the required braking deceleration, wherein the required braking moment comprises a front axle required braking moment and a rear axle required braking moment. In particular, the braking torque demand of the front and rear axles may be distributed according to an I-curve or a predefined curve.
And 140, determining a target motor braking moment of the vehicle according to the rear axle required braking moment and the maximum motor braking moment.
Specifically, the maximum motor braking torque that the vehicle can provide can be determined according to the state of the electric drive system of the vehicle at the current moment. When the maximum motor braking moment is greater than the rear axle required braking moment, the rear axle required braking moment is provided by the motor entirely, namely the target motor braking moment is equal to the rear axle required braking moment; when the maximum motor braking moment is smaller than the rear axle required braking moment, the rear axle braking moment is provided by the motor and the air pressure braking system together, the target motor braking moment is equal to the maximum moment of the rear axle required braking moment, and the rear axle required air pressure braking moment is equal to the rear axle required braking moment minus the target motor braking moment.
And 150, controlling the working state of the motor according to the braking torque of the target motor. Specifically, the target motor braking torque can be sent to the controller of the motor, so that the controller of the motor controls the working state of the motor.
And 160, determining target brake pressure of the vehicle according to the front axle required brake moment, the rear axle required brake moment and a brake system inverse model, wherein the target brake pressure comprises the front axle target brake pressure and the rear axle target brake pressure. Specifically, a front axle target brake pressure of the vehicle may be determined based on the front axle demand brake torque and the brake system inverse model, and a rear axle target brake pressure of the vehicle may be determined based on the rear axle demand brake torque and the brake system inverse model.
Step 170, according to the target brake pressure, the brake chamber pressure is adjusted by a brake pressure adjusting module. For example, the front axle target brake pressure and the rear axle target brake pressure are sent to the brake pressure adjustment module through the CAN bus to achieve tracking control of the target brake pressure through the brake pressure adjustment module.
In this embodiment, the brake pressure adjusting module may adjust the brake chamber pressure by acquiring the actual brake pressure of the brake chamber, then adjusting the operating state of the brake pressure adjusting module according to the target brake pressure and the actual brake pressure, then determining the duty ratio of the solenoid valve driving signal according to the operating state of the brake pressure adjusting module, and adjusting the brake chamber pressure according to the duty ratio.
It will be appreciated that, as shown in fig. 2, adjusting the operating state of the brake pressure adjustment module based on the target brake pressure and the actual brake pressure may include, but is not limited to, the following steps:
when the target braking pressure P tgt The working state of the brake pressure adjusting module is adjusted to enter a pressure maintaining state when the brake pressure adjusting module is equal to zero;
when the target braking pressure P tgt Is larger than zero and meets the first preset condition, adjustsThe working state of the brake pressure adjusting module enters a pressure maintaining state, and the meeting of the first preset condition comprises the target brake pressure P tgt And the actual braking pressure P act The difference value of (2) is smaller than or equal to a first threshold value;
when the target braking pressure P tgt The second preset condition is met, the working state of the brake pressure adjusting module is adjusted to enter a closed-loop supercharging state, and the second preset condition is met and comprises the target brake pressure P tgt And the actual braking pressure P act The difference value of (2) is larger than a first threshold value and smaller than or equal to a second threshold value;
when the target braking pressure P tgt The brake pressure adjusting module is larger than zero and meets a third preset condition, the working state of the brake pressure adjusting module is adjusted to enter an open-loop supercharging state, and the meeting of the third preset condition comprises the target brake pressure P tgt And the actual braking pressure P act Is greater than a second threshold value;
when the target braking pressure P tgt The brake pressure adjusting module is smaller than zero and meets a fourth preset condition, the working state of the brake pressure adjusting module is adjusted to enter a pressure maintaining state, and the fourth preset condition comprises the actual brake pressure P act With the target braking pressure P tgt The difference value of (2) is smaller than or equal to a first threshold value;
when the target braking pressure P tgt The working state of the brake pressure adjusting module is adjusted to enter a closed-loop pressure reducing state when the brake pressure adjusting module is smaller than zero and meets a fifth preset condition, wherein the fifth preset condition comprises the actual brake pressure P act With the target braking pressure P tgt The difference value of (2) is larger than a first threshold value and smaller than or equal to a second threshold value;
when the target braking pressure P tgt The working state of the brake pressure adjusting module is adjusted to enter an open-loop decompression state when the brake pressure adjusting module is smaller than zero and meets a sixth preset condition, wherein the meeting of the sixth preset condition comprises the actual brake pressure P act With the target braking pressure P tgt Is greater than a second threshold value;
wherein,,the first threshold value delta 1 Less than the second threshold value delta 2 。
In this embodiment, as shown in fig. 3, the brake pressure adjusting module includes a controller 310, a pressure increasing valve 320, a pressure reducing valve 330, a backup valve 340 and an air pressure sensor 350, and the pressure increasing valve 320, the pressure reducing valve 330, the backup valve 340 and the air pressure sensor 350 are all electrically connected to the controller 310. Specifically, one end of the pressure increasing valve 320 is connected to the air inlet 360, the other end of the pressure increasing valve 320 is connected to one end of the pressure reducing valve 330, one end of the air outlet 370 and one end of the standby valve 340, the other end of the pressure reducing valve 330 is connected to the air outlet 380, the other end of the standby valve 340 is connected to the standby air inlet 390, and the air pressure sensor 350 is disposed on the pipeline of the air outlet 370.
Taking the structure of the brake pressure adjusting module shown in fig. 3 as an example, determining the duty ratio of the solenoid valve driving signal according to the operation state of the brake pressure adjusting module may be performed in such a manner that the duty ratio of the solenoid valve driving signal includes the duty ratio of the pressure reducing valve driving signal and the duty ratio of the pressure increasing valve driving signal:
when the working state of the brake pressure regulating module is in a pressure maintaining state, the duty ratio of the electromagnetic valve driving signal is determined to be equal to zero, namely, the pressure increasing valve and the pressure reducing valve do not work, and the duty ratio PWM of the pressure increasing valve driving signal is determined inlet =0, duty cycle PWM of pressure reducing valve driving signal outlet ＝0；
When the working state of the brake pressure regulating module is in a closed-loop pressurizing state, determining that the duty ratio of the pressure reducing valve driving signal is equal to zero, and calculating the duty ratio of the pressure increasing valve driving signal through the duty ratio calculating module, namely, the pressure increasing valve is in the working state, the pressure reducing valve does not work, and the duty ratio PWM of the pressure reducing valve driving signal is calculated outlet ＝0；
When the working state of the brake pressure regulating module is in an open-loop pressurizing state, the duty ratio of the pressure-increasing valve driving signal is determined to be equal to zero, wherein the duty ratio of the pressure-increasing valve driving signal is equal to one hundred, namely the pressure-increasing valve is fully opened, the pressure-increasing valve is fully closed, and the duty ratio PWM of the pressure-increasing valve driving signal is determined at the moment inlet =100, duty cycle PWM of pressure relief valve drive signal outlet ＝0；
When the working state of the brake pressure regulating module is in a closed-loop pressure reducing state, the duty ratio of the pressure reducing valve driving signal is calculated through the duty ratio calculating module, and the duty ratio of the pressure increasing valve driving signal is determined to be equal to zero, namely the pressure increasing valve is not working, the pressure reducing valve is in the working state, and the duty ratio PWM of the pressure increasing valve driving signal is determined inlet ＝0；
When the working state of the brake pressure regulating module is in an open-loop decompression state, the duty ratio of the decompression valve driving signal is determined to be equal to one hundred, and the duty ratio of the pressure increasing valve driving signal is determined to be equal to zero, namely the decompression valve is fully opened and the pressure increasing valve is fully closed, and at the moment, the duty ratio PWM of the pressure increasing valve driving signal is determined inlet =0, duty cycle PWM of pressure reducing valve driving signal outlet ＝100。
In the above duty cycle calculation process, as shown in fig. 4, the duty cycle calculation module includes a first tracking differentiator, a second tracking differentiator, and a nonlinear feedback controller. P in FIG. 4 s An air source pressure signal is measured for a sensor or sent by a brake controller; p (P) tgt Target brake pressure signal, v, sent to a brake controller 1 And v 2 The target pressure signals and differential signals thereof are respectively transformed by the tracking differentiator; p (P) act For actual pressure, z is obtained by air pressure sensor in brake pressure regulating module 1 And z 2 The actual pressure signal and the differential signal thereof are respectively transformed by the tracking differentiator; PWM is a solenoid control command, i.e., duty cycle. If the brake pressure adjusting module is in the closed-loop supercharging state at this time, the PWM calculated at this time is a control command of the supercharging valve, that is, pwm=pwm inlet The method comprises the steps of carrying out a first treatment on the surface of the If the brake pressure adjusting module is in the closed-loop pressure reducing state at this time, the PWM calculated at this time is a control command of the pressure reducing valve, that is, pwm=pwm outlet 。
Specifically, a first tracking differentiator is used for braking the target pressure P tgt Transforming and generating a differential signal as a first differential signal; the second tracking differentiator is used for differentiating the actual braking pressure P act The filtering is performed and a differential signal is generated as a second differential signal to reduce the effect of noise. Wherein, the firstThe specific implementation of one tracking differentiator and the second tracking differentiator is shown in the following formula:
Figure BDA0003468339800000081
in the formula, k represents kT time, and T is sampling time; v is the input of the tracking differentiator, v=p in this embodiment tgt Or v=p act ；x 1 And x 2 I.e. the output of the tracking differentiator, representing the transformed or filtered target signal and its differentiated signal, respectively, x in the present invention 1 ＝v 1 、x 2 ＝v 2 Or x 1 ＝z 1 、x 2 ＝v 2 The method comprises the steps of carrying out a first treatment on the surface of the r and h are parameters to be selected; fhan (·) is a nonlinear function, which is expressed by the following formula:
Figure BDA0003468339800000082
in the above formula, d, a 0 、y、a 1 、a 2 And a are both intermediate variables of the calculation process; sign (·) represents a sign function; fsg (·) represents a nonlinear function, specifically expressed by the following formula:
Figure BDA0003468339800000091
the nonlinear feedback controller includes two parts, namely an error transformation and an error feedback control law. Wherein according to the target braking pressure P tgt And the actual braking pressure P act A control command of the pressure increasing valve or the pressure reducing valve, which is input as shown in the following formula:
Figure BDA0003468339800000092
in the above formula, e 1 For the converted target brake pressure v 1 And the converted actual brake pressure z 1 Deviation of (2); e, e 2 Differential signal v for target brake pressure 2 Differential signal z from actual brake pressure 2 Deviation of (2); e, e 0 E is 1 Integration over time.
Defining an error transformation function fal (·) as shown in the following formula:
Figure BDA0003468339800000093
in the above error function transformation formula, e represents the original error signal, and in this embodiment, e is taken as e 1 、e 2 、e 0 The method comprises the steps of carrying out a first treatment on the surface of the Alpha and delta are parameters to be selected.
For the feedback control law u, a feedback control law u shown in the following formula is set:
u＝β 0 fal(e 0 ,α 0 ,δ)+β 1 fal(e 1 ,α 1 ,δ)+β 2 fal(e 2 ,α 2 ,δ)
in the feedback control law formula, beta 0 、β 1 And beta 2 Is the feedback gain; alpha 0 、α 1 、α 2 And delta is a candidate parameter, and alpha can be selected generally 0 ＝0.25、α 1 ＝0.75、α 2 =1.5, δ=h, or δ=kh.
Thus, the control command for the pressure increasing valve or the pressure reducing valve is as follows:
PWM inlet /PWM outlet ＝u
furthermore, the parameter β in the feedback controller 1 According to the air source pressure P s The table is obtained by looking up so as to adapt to different air source pressures, and then the robustness of pressure control is improved; the remaining parameters can be obtained by calibrating the actual system.
In some embodiments, the above embodiments are applied to rear axle driven electric-only commercial vehicles, as shown in fig. 5, including but not limited to:
acquiring braking signal alpha brk The signal may be either a brake pedal displacement signal or a brake pedal force signal for reacting toThe braking intention of the driver.
The vehicle state data is obtained, and specifically comprises information such as road surface adhesion coefficient of a road on which the vehicle runs, mass of the vehicle, distance from the mass center of the vehicle to a front shaft and a rear shaft, mass center height of the vehicle, speed of the vehicle at the current moment, motor rotation speed, state of charge of a power battery and the like. May be estimated by onboard sensor measurements or algorithms.
Analysis of braking intention, i.e. from braking signal alpha brk Determining the required braking deceleration or braking intensity, and calculating the required braking moment T by combining the vehicle state information at the current moment total 。
The distribution of the braking moment required by the front axle and the rear axle, namely the braking moment T required according to the current requirement total Determining a front axle braking demand braking moment T according to the state of the vehicle at the current moment f And rear axle demand braking torque T r . For example, the braking torque required for the front and rear axles may be distributed according to an I-curve or a predefined curve.
Rear axle motor/pneumatic braking torque distribution, i.e. determining the maximum motor braking torque T which can be provided by the vehicle according to the state of the electric drive system of the vehicle at the current moment reg_max . If T reg_max ≥T r The braking torque required by the rear axle is provided by the motor, namely T r_reg_tgt ＝T r ，T r_reg_tgt Braking torque for a target motor; if T reg_max <T r The rear axle braking torque is then provided by the motor and pneumatic brake system 520 together, and T r_reg_tgt ＝T r_max ，T r_pneu ＝T r -T r_reg_tgt ，T r_pneu And air pressure braking moment is required for the rear axle.
Determining target braking pressure of front and rear axles, i.e. braking moment T according to front axle demand f And rear axle demand braking torque T r_pneu Determining front axle target braking pressure P at current moment by using inverse model of braking system f_tgt And rear axle target brake pressure P r_tgt 。
After obtaining the target motor braking torque T r_reg_tgt Then, each CAN bus brakes the moment T of the target motor r_reg_tgt Send toA motor controller, which controls the motor to output braking torque; at the same time, the front axle target braking pressure P is obtained f_tgt And rear axle target brake pressure P r_tgt After that, the front axle target braking pressure P is controlled by the CAN bus f_tgt And rear axle target brake pressure P r_tgt And the brake pressure is sent to a front and rear axle brake pressure adjusting module 510, and the brake pressure adjusting module 510 adjusts the brake chamber pressure so as to realize tracking control on target brake pressure.
In summary, in this embodiment, the multi-level logic threshold value is used and the open-loop control and the closed-loop control are combined, so that the rapidity and the accuracy of the pressure response are improved; the actual braking pressure P can be achieved by using a tracking differentiator act To reduce the effects of noise; the controller parameters are adjusted according to the air source pressure through the increasing/reducing valve control command calculation module, so that the method can adapt to different working conditions, the pressure control precision is improved, and the algorithm robustness is improved.
The embodiment of the invention provides a control device of an electric composite braking system, which comprises the following components:
at least one memory for storing a program;
at least one processor for loading the program to perform the control method of the electric compound brake system shown in fig. 1.
The content of the method embodiment of the invention is suitable for the device embodiment, the specific function of the device embodiment is the same as that of the method embodiment, and the achieved beneficial effects are the same as those of the method.
An embodiment of the present invention provides a storage medium in which a computer-executable program is stored, which when executed by a processor, is configured to implement a control method of an electric compound brake system shown in fig. 1.
In addition, the embodiment of the invention provides a commercial vehicle, and the braking control is performed by the control method of the electric composite braking system shown in fig. 1.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of one of ordinary skill in the art without departing from the spirit of the present invention. Furthermore, embodiments of the invention and features of the embodiments may be combined with each other without conflict.

Claims (5)

1. A control method of an electric compound brake system, characterized by comprising the steps of:
acquiring a braking signal and vehicle state data of a vehicle at the current moment;
determining a demanded braking deceleration from the braking signal;
determining a required braking moment according to the vehicle state data and the required braking deceleration, wherein the required braking moment comprises a front axle required braking moment and a rear axle required braking moment;
determining a target motor braking moment of the vehicle according to the rear axle required braking moment and the maximum motor braking moment;
controlling the working state of the motor according to the target motor braking torque;
determining a target braking pressure of the vehicle according to the front axle required braking moment, the rear axle required braking moment and a braking system inverse model, wherein the target braking pressure comprises a front axle target braking pressure and a rear axle target braking pressure;
acquiring the actual braking pressure of a braking air chamber;
the working state of the brake pressure adjusting module is adjusted according to the target brake pressure and the actual brake pressure, the brake pressure adjusting module comprises a controller, a pressure increasing valve, a pressure reducing valve, a standby valve and a pressure sensor, and the pressure increasing valve, the pressure reducing valve, the standby valve and the pressure sensor are electrically connected with the controller;
determining the duty ratio of a solenoid valve driving signal according to the working state of the brake pressure regulating module;
regulating the pressure of a brake chamber according to the duty ratio;
wherein said adjusting the operating state of the brake pressure adjustment module according to the target brake pressure and the actual brake pressure includes:
when the target braking pressure is equal to zero, adjusting the working state of the braking pressure adjusting module to enter a pressure maintaining state;
when the target braking pressure is greater than zero and a first preset condition is met, the working state of the braking pressure adjusting module is adjusted to enter a pressure maintaining state, wherein the meeting of the first preset condition comprises that the difference value between the target braking pressure and the actual braking pressure is smaller than or equal to a first threshold value;
when the target braking pressure is greater than zero and meets a second preset condition, adjusting the working state of the braking pressure adjusting module to enter a closed-loop supercharging state, wherein the second preset condition comprises that the difference value between the target braking pressure and the actual braking pressure is greater than a first threshold value and less than or equal to a second threshold value;
when the target braking pressure is greater than zero and a third preset condition is met, the working state of the braking pressure adjusting module is adjusted to enter an open-loop supercharging state, and the meeting of the third preset condition comprises that the difference value between the target braking pressure and the actual braking pressure is greater than a second threshold value;
when the target braking pressure is smaller than zero and a fourth preset condition is met, the working state of the braking pressure adjusting module is adjusted to enter a pressure maintaining state, and the fourth preset condition is met, wherein the difference value between the actual braking pressure and the target braking pressure is smaller than or equal to a first threshold value;
when the target braking pressure is smaller than zero and a fifth preset condition is met, the working state of the braking pressure adjusting module is adjusted to enter a closed-loop decompression state, and the fifth preset condition is met, wherein the difference value between the actual braking pressure and the target braking pressure is larger than a first threshold value and smaller than or equal to a second threshold value;
when the target braking pressure is smaller than zero and a sixth preset condition is met, the working state of the braking pressure adjusting module is adjusted to enter an open-loop decompression state, and the meeting of the sixth preset condition comprises that the difference value between the actual braking pressure and the target braking pressure is larger than a second threshold value;
wherein the first threshold value is smaller than the second threshold value;
the determining the duty ratio of the electromagnetic valve driving signal according to the working state of the brake pressure adjusting module comprises the following steps:
when the working state of the brake pressure adjusting module is in a pressure maintaining state, determining that the duty ratio of the electromagnetic valve driving signal is equal to zero;
when the working state of the brake pressure regulating module is in a closed-loop supercharging state, determining that the duty ratio of the pressure reducing valve driving signal is equal to zero, and calculating the duty ratio of the supercharging valve driving signal through a duty ratio calculating module;
when the working state of the brake pressure regulating module is in an open-loop supercharging state, determining that the duty ratio of the pressure reducing valve driving signal is equal to zero, wherein the duty ratio of the supercharging valve driving signal is equal to one hundred;
when the working state of the brake pressure regulating module is in a closed-loop decompression state, calculating the duty ratio of the decompression valve driving signal through the duty ratio calculating module, and determining that the duty ratio of the supercharging valve driving signal is equal to zero;
when the working state of the brake pressure regulating module is in an open-loop decompression state, determining that the duty ratio of the decompression valve driving signal is equal to one hundred, and the duty ratio of the supercharging valve driving signal is equal to zero;
wherein the duty cycle of the solenoid valve drive signal comprises the duty cycle of the pressure reducing valve drive signal and the duty cycle of the pressure increasing valve drive signal;
the duty cycle calculation module comprises a first tracking differentiator, a second tracking differentiator and a nonlinear feedback controller;
the first tracking differentiator is used for transforming the target braking pressure and generating a first differentiated signal;
the second tracking differentiator is used for filtering the actual braking pressure and generating a second differentiated signal;
the nonlinear feedback controller is used for calculating the duty ratio of the driving signal of the pressure increasing valve or the pressure reducing valve according to the air source pressure signal, the first differential signal and the second differential signal sent by the controller.
2. The method of claim 1, wherein the vehicle state data includes road adhesion coefficient, mass of the vehicle, distance of a vehicle center of mass to a front-rear axis, center of mass height of the vehicle, speed of the vehicle at a current time, motor speed, and power battery state of charge.
3. A control device of an electric compound brake system, characterized by comprising:
at least one memory for storing a program;
at least one processor for loading the program to perform the control method of an electric compound brake system according to any one of claims 1-2.
4. A storage medium having stored therein a computer executable program for implementing the control method of the electric compound brake system according to any one of claims 1-2 when executed by a processor.
5. A commercial vehicle characterized in that brake control is performed by the control method of an electric composite brake system according to any one of claims 1-2.
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