An adaptive optimization braking method and system for electric vehicles

Abstract

This invention provides an adaptive optimization braking method and system for electric vehicles. The method includes acquiring vehicle parameters of the electric vehicle and constructing a vehicle dynamics model based on the vehicle parameters; acquiring environmental parameters of the vehicle's operation and determining a constrained braking torque range based on the environmental parameters; determining the torque solution objective and state variables, and constructing an objective function based on the vehicle dynamics model, the torque solution objective, and the state variables; determining the constraint conditions based on the constrained braking torque range; solving the objective function based on the constraint conditions to output the objective solution; and distributing the torque corresponding to the objective solution to the front and rear wheels of the vehicle. This invention ensures the braking safety of the vehicle and the driving comfort of the driver in real time, while also improving the energy efficiency of the vehicle.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of automobile braking, and particularly relates to an adaptive optimization braking method and system for electric vehicles. BACKGROUND

[0002] Compared with traditional fuel vehicles, new energy vehicles have the advantages of zero pollution, low noise and higher comfort, and four-wheel hub electric vehicles integrate hub motors with wheels, and have higher flexibility, maneuverability and stability compared with other new energy vehicles. However, the problems of short driving range, imperfect charging infrastructure and high cost of power batteries still cause anxiety for consumers. Therefore, improving the driving range of four-wheel hub electric vehicles and alleviating the "range anxiety" of consumers are important means to promote the development strategy of four-wheel hub electric vehicles. Under urban working conditions, the energy loss caused by frequent braking of vehicles can account for 30% to 50% of the total driving energy of vehicles, and regenerative braking technology as an important part of the braking system of electric vehicles can recover part of the braking energy to improve energy utilization. Therefore, by recovering part of the above braking energy loss, the driving range of four-wheel hub electric vehicles can be extended to a certain extent.

[0003] The core idea of the regenerative braking control strategy is that the motor generates a feedback current during braking, thereby converting part of the kinetic energy in the braking process into electrical energy and storing it in the battery for recycling. Regenerative braking has the advantages of controllable precision and fast response speed, and can meet the economic needs of normal braking and emergency braking conditions, but braking safety is always the primary goal that needs to be met in the vehicle braking process. The working range of regenerative braking is smaller than that of friction braking, and cannot meet the braking demand in high-intensity braking conditions. Therefore, giving full play to the respective advantages of regenerative braking and friction braking of four-wheel hub electric vehicles and adaptively coordinating the distribution ratio of the two is of great significance to improve the safety and economy of the vehicle.

[0004] For the prior art, most of the braking schemes only consider the braking effect, but ignore the comfort of the vehicle during braking, thereby affecting the driving experience of the driver. SUMMARY

[0005] In order to solve the above technical problems, the application provides an adaptive optimization braking method and system for electric vehicles, which solves the technical problems in the prior art.

[0006] In a first aspect, the application provides the following technical scheme, an adaptive optimization braking method for electric vehicles, comprising:

[0007] Obtaining vehicle parameters of the electric vehicle, and constructing an automobile dynamics model based on the vehicle parameters;

[0008] acquire an environmental parameter of vehicle driving, determine a constraint braking torque range based on the environmental parameter;

[0009] determine a torque solving target and a state variable, construct a target function based on the vehicle dynamics model, the torque solving target and the state variable;

[0010] determine a function solving constraint condition based on the constraint braking torque range;

[0011] solve the target function based on the solving constraint condition to output a target solution, and distribute a torque corresponding to the target solution to front and rear wheels of the vehicle.

[0012] Compared with the prior art, the present application has the beneficial effects that: the present application firstly acquires vehicle parameters of an electric vehicle, constructs a vehicle dynamics model based on the vehicle parameters; then acquires an environmental parameter of vehicle driving, determines a constraint braking torque range based on the environmental parameter; then determines a torque solving target and a state variable, constructs a target function based on the vehicle dynamics model, the torque solving target and the state variable; then determines a function solving constraint condition based on the constraint braking torque range; finally, solves the target function based on the solving constraint condition to output a target solution, and distributes a torque corresponding to the target solution to front and rear wheels of the vehicle. The present application determines a corresponding braking mode according to an environmental parameter, and determines a dynamic function solving constraint condition, so as to ensure that the vehicle can meet the safety constraint of the environmental parameter in the braking process, and simultaneously determines a multi-target and multi-constraint composite braking distribution target function. By solving the target function, the best distribution scheme of hydraulic torque and motor torque is determined, so as to ensure the braking safety of the vehicle and the driving comfort of the driver in real time, and simultaneously improve the energy efficiency utilization rate of the vehicle.

[0013] Preferably, the vehicle dynamics model is:

[0014] ;

[0015] ;

[0016] In the formula, is the vehicle weight, is the vehicle longitudinal speed is the first derivative of the vehicle longitudinal speed, are respectively the frictional forces between the front wheel and the ground and the rear wheel and the ground, are respectively the air resistance coefficient and the vehicle window windward area, is the air density, is the gravitational acceleration, is the road slope, is the rolling resistance, moment of inertia of the vehicle, first derivative of the wheel or rear wheel speed, rolling radius of the tire, friction between the wheel or rear wheel and the ground, total braking torque of the front or rear wheel, respectively, the front wheel, the rear wheel.

[0017] Preferably, the step of determining the range of the braking torque based on the environmental parameters comprises:

[0018] a first minimum torque calculated based on the environmental parameters and a first maximum torque :

[0019] ;

[0020] ;

[0021] wherein, respectively, the air resistance coefficient, the windward area of the vehicle window, the air density, the gravitational acceleration, the road slope, the vehicle longitudinal speed, the vehicle weight, the rolling radius of the tire, respectively, the minimum and maximum safe deceleration, the moment of inertia of the vehicle;

[0022] a second minimum torque calculated based on the environmental parameters , a second maximum torque and a speed limit torque :

[0023] ;

[0024] ;

[0025] ;

[0026] wherein, the speed limit target speed, respectively, the speed limit position, the current position of the vehicle, the maximum deceleration allowed by the comfort level, the distance margin;

[0027] determining whether the vehicle meets the first requirement, the second requirement and the third requirement, if the vehicle meets the first requirement, the second requirement and the third requirement at the same time, the vehicle adopts the regenerative braking mode to brake, if the vehicle does not meet the first requirement or the second requirement or the third requirement, the vehicle adopts the regenerative braking and friction braking mixed mode to brake, so as to obtain the braking mode of the vehicle;

[0028] calculating the total torque based on the braking mode of the vehicle :

[0029] ;

[0030] wherein, is the reduction ratio of the decelerator, are the maximum motor torques of the front wheels and the rear wheels respectively, is the maximum value of the hydraulic torque;

[0031] calculating the minimum constraint braking torque , the maximum constraint braking torque , the minimum constraint braking torque , the maximum constraint braking torque , the speed limit torque and the total torque , so as to obtain the constraint braking torque range:

[0032] ;

[0033] .

[0034] Preferably, the target function is:

[0035] ;

[0036] ;

[0037] ;

[0038] ;

[0039] ;

[0040] wherein, is the terminal time, are the first, second and third energy weights respectively, are the motor power, the hydraulic loss and the resistance loss respectively, are the first weight and the second weight respectively, is the longitudinal speed of the vehicle at the terminal time,​​ For ideal speed, To solve for the change in the target torque, To solve for the torque, These are the front wheel hydraulic torque, rear wheel hydraulic torque, front wheel motor torque, and rear wheel motor torque, respectively. These are energy efficiency impact items, terminal state penalty items, and state quantity control items.

[0041] Preferably, the constraint conditions for solving the function are:

[0042] ;

[0043] ; ;

[0044] ; ;

[0045] ; ;

[0046] ; ;

[0047] In the formula, The reduction ratio of the reducer. These are the air drag coefficient and the windward area of ​​the car window, respectively. air density, It is the acceleration due to gravity. For road slope, For the longitudinal speed of the vehicle, For vehicle weight, The tire's rolling radius, Let t be the longitudinal speed of the vehicle. The first derivative, Let be the vehicle's moment of inertia. The first derivative of the safe distance at time t. Let be the maximum value of the hydraulic torque at time t. Let be the hydraulic torque at time t. Let t be the maximum motor torque of the front or rear wheel. Let be the motor torque of the front or rear wheel at time t. Let be the total braking torque at time t. Let be the change in motor torque of the front or rear wheel at time t. Let be the change in hydraulic torque at time t. This represents the change in the maximum value of the hydraulic torque at time t. This represents the change in the maximum motor torque of the front or rear wheel at time t. is the vehicle power at time t, are maximum and minimum values of the vehicle power, respectively, respectively represent front and rear wheels.

[0048] Preferably, the step of solving the objective function based on the solving constraint condition to output the target solution specifically comprises:

[0049] discretizing the objective function and determining a prediction equation under different sampling distances based on the previous Euler method and the state transformation equation, solving the discretized objective function based on the prediction equation and through a PSO algorithm to obtain an optimal solution under a sampling distance W , the first element in the optimal solution is taken as a first prediction step is output, and state information is updated at the next sampling distance and the solving process is repeated until braking is completed to output the target solution:

[0050] ;

[0051] ;

[0052] wherein, is a prediction equation of the step under the sampling distance W, is a maximum prediction step, are optimal front and rear wheel hydraulic torque, optimal front and rear wheel motor torque, respectively.

[0053] In a second aspect, the present application provides the following technical solution, an adaptive optimization braking system for an electric vehicle, the system comprising:

[0054] a construction module configured to acquire vehicle parameters of the electric vehicle and construct a vehicle dynamics model based on the vehicle parameters;

[0055] a range module configured to acquire environmental parameters of vehicle driving and determine a constraint braking torque range based on the environmental parameters;

[0056] a function module configured to determine a torque solving objective and state variables and construct an objective function based on the vehicle dynamics model, the torque solving objective and the state variables;

[0057] a condition module configured to determine a function solving constraint condition based on the constraint braking torque range;

[0058] a solving module configured to solve the objective function based on the solving constraint condition to output a target solution and distribute the torque corresponding to the target solution to front and rear wheels of the vehicle.

[0059] ​In a third aspect, the present application provides a computer comprising a memory, a processor, and a computer program stored in the memory and capable of running on the processor, wherein the processor implements the adaptive optimal braking method for electric vehicles when executing the computer program.

[0060] In a fourth aspect, the present application provides a storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the adaptive optimal braking method for electric vehicles. BRIEF DESCRIPTION OF DRAWINGS

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0062] Figure 1 A flow chart of the adaptive optimal braking method for electric vehicles provided by the first embodiment of the present application;

[0063] Figure 2 A structural block diagram of the adaptive optimal braking system for electric vehicles provided by the second embodiment of the present application;

[0064] Figure 3 A hardware structure schematic diagram of the computer provided by another embodiment of the present application.

[0065] The embodiments of the present application will be further described below with reference to the drawings. DETAILED DESCRIPTION

[0066] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the embodiments of the present application, and cannot be understood as limiting the present application.

[0067] Embodiment one

[0068] In the first embodiment of the present application, as shown in Figure 1 An adaptive optimal braking method for electric vehicles comprises:

[0069] S1, obtaining vehicle parameters of the electric vehicle, and constructing an automobile dynamics model based on the vehicle parameters;

[0070] The automobile dynamics model is:

[0071] ;

[0072] ;

[0073] wherein, is the vehicle mass, is the vehicle longitudinal speed is the first derivative of the vehicle longitudinal speed, are the friction forces between the front wheels and the ground respectively, are the air resistance coefficient and the windward area of the vehicle respectively, is the air density, is the gravity acceleration, is the road slope, is the rolling resistance, is the moment of inertia of the wheel or the rear wheel, is the first derivative of the wheel or the rear wheel speed, is the tire rolling radius, is the friction force between the wheel or the rear wheel and the ground, is the total braking torque of the front wheel or the rear wheel, denote the front wheel and the rear wheel respectively;

[0074] Specifically, the above automobile dynamics model is a vehicle braking model and four wheel distance balance equations respectively, and in the automobile dynamics model of the application, the total braking distance is the sum of the regenerative braking torque and the friction braking torque, which correspond to the motor braking and hydraulic braking respectively.

[0075] S2, obtaining an environmental parameter of vehicle driving, determining a constraint braking torque range based on the environmental parameter;

[0076] The step S2 comprises:

[0077] S21, calculating a first minimum torque and a first maximum torque based on the environmental parameter:

[0078] ;

[0079] ;

[0080] wherein, are the air resistance coefficient and the windward area of the vehicle respectively, is the air density, is the gravity acceleration, is the road slope, is the vehicle longitudinal speed, is the vehicle mass, is the tire rolling radius, respectively minimum, maximum safe deceleration, moment of inertia of the vehicle;

[0081] Specifically, the first minimum moment and the first maximum moment are minimum braking moment and maximum braking moment meeting distance safety, where the distance safety specifically refers to the distance between the vehicle and the preceding vehicle.

[0082] S22, a second minimum moment calculated based on the environment parameter , a second maximum moment , and a speed limit moment :

[0083] ;

[0084] ;

[0085] ;

[0086] wherein, is the speed of the speed limit target, are the speed limit position and the current position of the vehicle respectively, is the maximum deceleration allowed by the comfort level, is the distance margin;

[0087] Specifically, the second minimum moment and the second maximum moment here are respectively the minimum braking moment and the maximum braking moment required for complete braking target, and the speed limit moment here specifically refers to the maximum allowed braking moment under the speed limit constraint.

[0088] S23, judging whether the vehicle meets the first requirement, the second requirement and the third requirement, if the vehicle meets the first requirement, the second requirement and the third requirement at the same time, the vehicle adopts the regenerative braking mode for braking, if the vehicle does not meet the first requirement or the second requirement or the third requirement, the vehicle adopts the regenerative braking and friction braking hybrid mode for braking, to obtain the braking mode of the vehicle;

[0089] Specifically, the first requirement here is whether the distance between the vehicle and the preceding vehicle is not less than the safety distance, the second requirement is whether the vehicle meets the speed limit requirement, and the third requirement is whether the vehicle can meet the braking target, if the distance between the vehicle and the preceding vehicle is greater than the safety distance, the vehicle meets the speed limit requirement and meets the braking target, it is considered that the first requirement, the second requirement and the third requirement are met, and vice versa, where the braking target refers to the total braking distance, i.e. the sum of the relative distance and the distance margin between the two, and the distance margin is adjusted according to the congestion of the current road.

[0090] S24, calculating a total moment based on the braking mode of the vehicle :

[0091] ;

[0092] In the formula, The reduction ratio of the reducer. These are the maximum motor torques for the front and rear wheels, respectively. This represents the maximum value of the hydraulic torque;

[0093] Specifically, the total torque is determined here according to the different braking modes used. When in the mixed mode of regenerative and friction braking, it indicates that the hydraulic torque and the motor torque both participate in braking. When in regenerative mode, it indicates that only the motor torque participates in braking.

[0094] S25, Based on the first minimum torque First maximum torque Second minimum torque Second maximum torque Speed ​​limiting torque and total torque Calculate the minimum constraint braking torque Maximum constrained braking torque To obtain the range of constrained braking torque:

[0095] ;

[0096] .

[0097] S3. Determine the torque solution objective and state variables, and construct an objective function based on the vehicle dynamics model, the torque solution objective, and the state variables;

[0098] The objective of the torque calculation here is... , The state variable is , These represent longitudinal distance and safety distance, respectively.

[0099] The objective function is:

[0100] ;

[0101] ;

[0102] ;

[0103] ;

[0104] ;

[0105] In the formula, For the terminal time, The first, second, and third energy weights are respectively. These are motor power, hydraulic loss, and resistance loss, respectively. These are the first weight and the second weight, respectively. Let be the longitudinal speed of the vehicle at the terminal moment. For ideal speed, To solve for the change in the target torque, To solve for the torque, These are the front wheel hydraulic torque, rear wheel hydraulic torque, front wheel motor torque, and rear wheel motor torque, respectively. These are energy efficiency impact items, terminal state penalty items, and state quantity control items, respectively.

[0106] Specifically, By making the first The torque at time t is calculated by subtracting the term from each item in the objective function. The torque at each moment is calculated to obtain the various terms in the objective, and then the results are accumulated.

[0107] S4. Solve the constraint conditions by determining the function based on the range of the constraint braking torque;

[0108] The constraint conditions for solving the function are as follows:

[0109] ;

[0110] ; ;

[0111] ; ;

[0112] ; ;

[0113] ; ;

[0114] In the formula, The reduction ratio of the reducer. These are the air drag coefficient and the windward area of ​​the car window, respectively. air density, It is the acceleration due to gravity. For road slope, For the longitudinal speed of the vehicle, For vehicle weight, The tire's rolling radius, Let t be the longitudinal speed of the vehicle. The first derivative, Let be the vehicle's moment of inertia. The first derivative of the safe distance at time t. Let be the maximum value of the hydraulic torque at time t. Let be the hydraulic torque at time t. Let t be the maximum motor torque of the front or rear wheel. Let be the motor torque of the front or rear wheel at time t. Let be the total braking torque at time t. Let be the change in motor torque of the front or rear wheel at time t. Let be the change in hydraulic torque at time t. This represents the change in the maximum value of the hydraulic torque at time t. This represents the change in the maximum motor torque of the front or rear wheel at time t. Let t be the vehicle's battery level at time t. These are the maximum and minimum values ​​of the vehicle's battery level, respectively. These represent the front wheel and the rear wheel, respectively.

[0115] S5. Solve the objective function based on the aforementioned constraints to output the objective solution, and distribute the torque corresponding to the objective solution to the front and rear wheels of the vehicle.

[0116] Specifically, step S5 is as follows:

[0117] The objective function is discretized, and prediction equations for different sampling distances are determined based on the Euler method and the state transition equation. The discretized objective function is then solved using the PSO algorithm based on these prediction equations to obtain the optimal solution for the sampling distance W. The first element in the optimal solution Output the solution, update the state information at the next sampling distance, and repeat the solution process until braking ends, to output the target solution:

[0118] ;

[0119] ;

[0120] In the formula, For the sampling distance W, the first The prediction equation for the step, For the maximum prediction step size, These are the optimal front wheel hydraulic torque, optimal rear wheel hydraulic torque, optimal front wheel motor torque, and optimal rear wheel motor torque, respectively.

[0121] The adaptive optimization braking method for electric vehicles provided in Embodiment 1 of this invention first obtains the vehicle parameters of the electric vehicle and constructs a vehicle dynamics model based on the vehicle parameters; then, it obtains the environmental parameters of the vehicle's operation and determines the range of constrained braking torque based on the environmental parameters; then, it determines the torque solution objective and state variables, and constructs an objective function based on the vehicle dynamics model, the torque solution objective, and the state variables; then, it determines the function solution constraint conditions based on the constrained braking torque range; finally, it solves the objective function based on the solution constraint conditions to output the objective solution, and distributes the torque corresponding to the objective solution to the front and rear wheels of the vehicle. This invention determines the corresponding braking mode based on environmental parameters and determines dynamic function solution constraint conditions to ensure that the vehicle can meet the safety constraints of environmental parameters during braking. At the same time, it determines a multi-objective, multi-constraint composite braking distribution objective function. By solving the objective function, it determines the optimal distribution scheme of hydraulic torque and motor torque, ensuring the braking safety of the vehicle and the driving comfort of the driver in real time, while also improving the energy efficiency of the vehicle.

[0122] Example 2

[0123] like Figure 2 As shown, in Embodiment 2 of the present invention, an adaptive optimization braking system for electric vehicles is provided, the system comprising:

[0124] Module 1 is used to acquire vehicle parameters of electric vehicles and construct a vehicle dynamics model based on the vehicle parameters;

[0125] Range module 2 is used to acquire environmental parameters of vehicle driving and determine the range of constraint braking torque based on the environmental parameters;

[0126] Function module 3 is used to determine the torque solution objective and state variables, and to construct an objective function based on the vehicle dynamics model, the torque solution objective, and the state variables;

[0127] Condition module 4 is used to solve the constraint conditions based on the constraint braking torque range determination function;

[0128] The solver module 5 is used to solve the objective function based on the solution constraints, output the objective solution, and distribute the torque corresponding to the objective solution to the front and rear wheels of the car.

[0129] The identification module 2 is used for:

[0130] The first minimum torque calculated based on the environmental parameters and the first maximum torque :

[0131] ;

[0132] ;

[0133] In the formula, These are the air drag coefficient and the windward area of ​​the car window, respectively. air density, It is the acceleration due to gravity. For road slope, For the longitudinal speed of the vehicle, For vehicle weight, The tire's rolling radius, These are the minimum and maximum safe decelerations, respectively. The moment of inertia of the vehicle;

[0134] The second minimum torque calculated based on the environmental parameters Second maximum torque and speed limiting torque :

[0135] ;

[0136] ;

[0137] ;

[0138] In the formula, To limit the speed of the target, These are the speed limit location and the vehicle's current location, respectively. The maximum deceleration allowed by the comfort level. This is the distance margin;

[0139] Determine whether the vehicle meets the first, second, and third requirements. If the vehicle meets all three requirements, the vehicle will use regenerative braking mode. If the vehicle does not meet the first, second, or third requirements, the vehicle will use a hybrid mode of regenerative braking and friction braking to obtain the vehicle's braking mode.

[0140] Calculate the total torque based on the vehicle's braking mode. :

[0141] ;

[0142] In the formula, The reduction ratio of the reducer. These are the maximum motor torques for the front and rear wheels, respectively. This represents the maximum value of the hydraulic torque;

[0143] Based on the first minimum torque First maximum torque Second minimum torque Second maximum torque Speed ​​limiting torque and total torque Calculate the minimum constraint braking torque Maximum constrained braking torque To obtain the range of constrained braking torque:

[0144] ;

[0145] .

[0146] The solution module 5 is specifically used for:

[0147] The objective function is discretized, and prediction equations for different sampling distances are determined based on the Euler method and the state transition equation. The discretized objective function is then solved using the PSO algorithm based on these prediction equations to obtain the optimal solution for the sampling distance W. The first element in the optimal solution Output the solution, update the state information at the next sampling distance, and repeat the solution process until braking ends, to output the target solution:

[0148] ;

[0149] ;

[0150] In the formula, For the sampling distance W, the first The prediction equation for the step, For the maximum prediction step size, These are the optimal front wheel hydraulic torque, optimal rear wheel hydraulic torque, optimal front wheel motor torque, and optimal rear wheel motor torque, respectively.

[0151] In other embodiments of the present invention, the present invention provides the following technical solution: a computer, including a memory 102, a processor 101, and a computer program stored in the memory 102 and executable on the processor 101, wherein the processor 101 executes the computer program to implement the electric vehicle adaptive optimization braking method as described above.

[0152] Specifically, the processor 101 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement the embodiments of the present invention.

[0153] The memory 102 may include a large-capacity memory for data or instructions. For example, and not limitingly, the memory 102 may include a hard disk drive (HDD), a floppy disk drive, a solid-state drive (SSD), flash memory, an optical disk drive, a magneto-optical disk drive, magnetic tape, or a Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, the memory 102 may include removable or non-removable (or fixed) media. Where appropriate, the memory 102 may be internal or external to a data processing device. In a particular embodiment, the memory 102 is non-volatile memory. In a particular embodiment, the memory 102 includes read-only memory (ROM) and random access memory (RAM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable read-only memory (PROM), an erasable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), an electrically alterable read-only memory (EAROM), or flash memory, or a combination of two or more of these. Where appropriate, the RAM can be Static Random-Access Memory (SRAM) or Dynamic Random-Access Memory (DRAM). DRAM can be Fast Page Mode Dynamic Random Access Memory (FPMDRAM), Extended Data Out Dynamic Random Access Memory (EDODRAM), Synchronous Dynamic Random-Access Memory (SDRAM), etc.

[0154] The memory 102 can be used to store or cache various data files that need to be processed and / or used for communication, as well as possible computer program instructions executed by the processor 101.

[0155] The processor 101 implements the above-described adaptive optimization braking method for electric vehicles by reading and executing computer program instructions stored in the memory 102.

[0156] In some embodiments, the computer may further include a communication interface 103 and a bus 100. For example, Figure 3 As shown, the processor 101, memory 102, and communication interface 103 are connected through bus 100 and complete communication with each other.

[0157] The communication interface 103 is used to enable communication between the various modules, devices, units, and / or equipment in the embodiments of the present invention. The communication interface 103 can also enable data communication with other components such as external devices, image / data acquisition devices, databases, external storage, and image / data processing workstations.

[0158] Bus 100 includes hardware, software, or both, that couples components of a computer device together. Bus 100 includes, but is not limited to, at least one of the following: data bus, address bus, control bus, expansion bus, and local bus. For example, and not as a limitation, bus 100 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable buses, or a combination of two or more of these. Where appropriate, bus 100 may include one or more buses. Although specific buses are described and illustrated in the embodiments of the present invention, the present invention is contemplated by any suitable bus or interconnect.

[0159] The computer can execute the electric vehicle adaptive optimization braking method of the present invention based on the acquired electric vehicle adaptive optimization braking system, thereby realizing electric vehicle adaptive optimization braking.

[0160] In some further embodiments of the present invention, in conjunction with the above-described adaptive optimization braking method for electric vehicles, the present invention provides the following technical solution: a storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the above-described adaptive optimization braking method for electric vehicles.

[0161] Those skilled in the art will understand that the logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can mean any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0162] More specific examples of readable media (a non-exhaustive list) include: electrical connections (electronic devices) with one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0163] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0164] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0165] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for adaptive optimization braking of an electric vehicle, characterized in that, The method comprises: acquiring vehicle parameters of the electric vehicle, and constructing a vehicle dynamics model based on the vehicle parameters; acquiring environmental parameters of vehicle driving, and determining a constrained braking torque range based on the environmental parameters; determining a torque solving target and state variables, and constructing a target function based on the vehicle dynamics model, the torque solving target and the state variables; determining a function solving constraint condition based on the constrained braking torque range; solving the target function based on the solving constraint condition to output a target solution, and distributing a torque corresponding to the target solution to front and rear wheels of the vehicle.

2. The adaptive optimized braking method for electric vehicles of claim 1, wherein, The vehicle dynamics model is: ； ； wherein is the vehicle mass, is the vehicle longitudinal speed is the first derivative of the vehicle longitudinal speed, are the friction forces between the front and rear wheels and the ground, respectively, are the air resistance coefficients and the windward area of the vehicle windows, respectively, is the air density, is the gravitational acceleration, is the road slope, is the rolling resistance, is the moment of inertia of the front or rear wheel, is the first derivative of the front or rear wheel speed, is the tire rolling radius, is the friction force between the front or rear wheel and the ground, is the total braking torque of the front or rear wheel, denote the front and rear wheels, respectively.

3. The adaptive optimized braking method for electric vehicles of claim 1, wherein, The step of determining the constrained braking torque range based on the environmental parameters comprises: a first minimum torque calculated based on the environmental parameter and a first maximum torque : ； ； wherein, respectively the air resistance coefficient, the windward area of the vehicle window, the air density, the gravitational acceleration, the road slope, the vehicle longitudinal speed, the vehicle weight, the tire rolling radius, respectively the minimum and maximum safe deceleration, the moment of inertia of the vehicle; a second minimum torque calculated based on the environmental parameter , a second maximum torque , and a speed-limited torque : ； ； ； wherein is the speed of the speed limit target, is the speed limit location, respectively the current location of the vehicle, is the maximum deceleration allowed for the comfort level, is the distance margin; determining whether the vehicle meets first, second and third requirements, and if the vehicle meets the first, second and third requirements simultaneously, the vehicle adopts a regenerative braking mode for braking, and if the vehicle does not meet the first, second or third requirement, the vehicle adopts a regenerative braking and friction braking hybrid mode for braking to obtain a braking mode of the vehicle; Vehicle-based brake mode calculation of total torque : ； In the formula, is the reduction ratio of the reduction gear, are the maximum motor torques of the front and rear wheels, respectively, is the maximum value of the hydraulic torque; based on the first minimum torque , the first maximum torque , the second minimum torque , the second maximum torque , the speed-limited torque , and the total torque calculating a minimum constrained braking torque , a maximum constrained braking torque to obtain a constrained braking torque range: ； 。 4. The method of adaptive optimization braking for electric vehicles of claim 1, wherein, The target function is: ； ； ； ； ； In the formula, is the terminal time, are respectively the first, second and third energy weights, are respectively the motor power, hydraulic loss and resistance loss, are respectively the first weight and the second weight, is the vehicle longitudinal speed at the terminal time, is the ideal speed, is the change amount of the torque solving target, is the torque solving target, are respectively the front wheel hydraulic torque, the rear wheel hydraulic torque, the front wheel motor torque and the rear wheel motor torque, are respectively the energy efficiency influence term, the terminal state penalty term and the state quantity control term.

5. The method of adaptive optimization braking for electric vehicles of claim 4, wherein, The function solving constraint condition is: ； ； ； ； ； ； ； ； ； wherein, is a reduction ratio of the reduction gear, are respectively an air resistance coefficient, a windward area of the vehicle window, is an air density, is a gravitational acceleration, is a road slope, is a vehicle longitudinal speed, is a vehicle weight, is a tire rolling radius, is a first derivative of the vehicle longitudinal speed at time t, is a moment of inertia of the vehicle, is a first derivative of the safety distance at time t, is a maximum value of the hydraulic torque at time t, is the hydraulic torque at time t, is a maximum motor torque of the front wheel or the rear wheel at time t, is a motor torque of the front wheel or the rear wheel at time t, is a total braking torque at time t, is a change amount of the motor torque of the front wheel or the rear wheel at time t, is a change amount of the hydraulic torque at time t, is a change amount of the maximum value of the hydraulic torque at time t, is a change amount of the maximum motor torque of the front wheel or the rear wheel at time t, is a vehicle electric quantity at time t, are respectively a maximum value and a minimum value of the vehicle electric quantity, respectively indicate the front wheel and the rear wheel.

6. The method of adaptive optimization braking for electric vehicles of claim 1, wherein, The step of solving the target function based on the solving constraint condition to output a target solution is specifically: Discretize the objective function and determine a prediction equation under different sampling distances based on the previous Euler method and the state transition equation, solve the discretized objective function based on the prediction equation and through the PSO algorithm to obtain an optimal solution under the sampling distance W output the first element in the optimal solution output and update the state information at the next sampling distance and repeat the solving process until the braking ends to output the target solution: ； ； In the formula, is the maximum prediction step size, is the prediction equation of the step, is the maximum prediction step size, are the optimal front wheel hydraulic torque, the optimal rear wheel hydraulic torque, the optimal front wheel motor torque, and the optimal rear wheel motor torque, respectively.

7. An electric vehicle adaptive optimized braking system, characterized by, The system comprises: a construction module configured to acquire vehicle parameters of the electric vehicle, and construct a vehicle dynamics model based on the vehicle parameters; a range module configured to acquire environmental parameters of vehicle driving, and determine a constrained braking torque range based on the environmental parameters; a function module configured to determine a torque solving target and state variables, and construct a target function based on the vehicle dynamics model, the torque solving target and the state variables; a condition module configured to determine a function solving constraint condition based on the constrained braking torque range; a solving module configured to solve the target function based on the solving constraint condition to output a target solution, and distribute a torque corresponding to the target solution to front and rear wheels of the vehicle.

8. A computer comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the computer program to implement the electric vehicle adaptive optimization braking method of any one of claims 1 to 6.

9. A storage medium, characterized by The storage medium has the computer program stored thereon, and the computer program is executed by the processor to implement the electric vehicle adaptive optimization braking method of any one of claims 1 to 6.

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