Brake energy recovery strategy simulation method and device, electronic equipment and storage medium

Abstract

The invention discloses a braking energy recovery strategy simulation method and device, electronic equipment and a storage medium, and relates to the technical field of load response simulation. Determining a recovery coefficient and a recovery mark; calculating an ideal curve distribution ratio; when the motor is driven or the recovery mark is false, the torque of the motor is calculated according to a kinetic equation, the energy recovery model is only responsible for transmitting a result, and when the recovery mark is true, recovery is carried out, and the required torque of the negative torque is output; front axle brake pressure is calculated through the vehicle rolling radius and the front axle brake coefficient; and the rear axle braking pressure is calculated through the vehicle rolling radius and the rear axle braking coefficient. According to the braking energy recovery strategy simulation method and device, the electronic equipment and the storage medium provided by the embodiment of the invention, the problem that the reaction torque error is too large due to the fact that the simulation strategy is too simple is solved, correction of the reverse dragging torque strength is completed, and the simulation load response is closer to the reverse dragging load response of a real user.

Description

Technical Field

[0001] The present application relates to the field of load response technology, and in particular to a braking energy recovery strategy simulation method, a braking energy recovery strategy simulation device, an electronic device and a storage medium. Background Art

[0002] With the development of the new energy vehicle industry, high-performance motor load response has brought more component failure problems, and vehicle load response simulation has become a necessary research direction. Pure electric vehicles have a special working condition. During braking and coasting, the motor participates in braking to generate negative torque. The load response at this time is related to the energy recovery strategy and is not easy to simulate accurately. Summary of the invention

[0003] The purpose of the present invention is to provide a braking energy recovery strategy simulation method, device, electronic device and storage medium, which solves the problem of excessive anti-torque error caused by overly simple simulation strategy, completes the correction of anti-drag torque strength, and makes the simulation load response closer to the anti-drag load response of real users.

[0004] The present invention provides the following scheme:

[0005] According to one aspect of the present invention, a braking energy recovery strategy simulation method is provided, the braking energy recovery strategy simulation method comprising:

[0006] Confirm vehicle parameters related to energy recovery strategy, as well as input and output signals of control strategy model;

[0007] Calculate total braking force and braking intensity;

[0008] Determine the recovery factor and recovery symbol;

[0009] Calculate the ideal curve distribution ratio;

[0010] When the motor is driven, or the recovery flag is false, the motor torque is calculated according to the dynamic equation, and the energy recovery model is only responsible for transmitting the result. When the recovery flag is true, recovery is performed and the negative torque demand torque is output;

[0011] Calculate the front axle brake pressure according to the ideal curve distribution ratio;

[0012] Calculate the rear axle brake pressure according to the ideal curve distribution ratio;

[0013] The torque output result is based on the current motor demand.

[0014] Optional vehicle strategies related to the energy recovery strategy include: wheelbase, frontal area, distance from center of mass to front axle, curb weight, fully loaded weight, tire rolling radius, drag coefficient, and rolling resistance coefficient.

[0015] Optionally, the input signals of the control strategy model include: battery SOC, front axle braking coefficient, rear axle braking coefficient, braking pressure, main reduction ratio, vehicle load signal, mechanical transmission efficiency, maximum motor driving torque, maximum motor recovery torque, and vehicle speed.

[0016] Optionally, the output signals of the control strategy model include: braking intensity, braking distribution coefficient, front axle braking pressure, motor required torque, rear axle braking pressure, and total braking force.

[0017] Optionally, calculating the total braking force and braking intensity includes:

[0018] The total braking force is calculated according to the following formula:

[0019] F b =(k bf +k br )×2×Pa÷r

[0020] Among them, k bf is the front axle braking coefficient, k br is the rear axle braking coefficient, Pa is the braking pressure, and r is the vehicle rolling radius.

[0021] Optionally, calculating the total braking force and braking intensity includes:

[0022] The braking strength is calculated according to the following formula:

[0023] z=F b ÷m÷g

[0024] Among them, F b is the total braking force, m is the vehicle weight, and g is the acceleration due to gravity.

[0025] Optionally, calculating the ideal curve distribution ratio includes:

[0026] When the front and rear wheels of the vehicle are locked simultaneously during braking, the ideal braking force distribution curve is calculated according to the following formula:

[0027]

[0028] Among them, F bf is the front axle braking force, F br Braking force for the rear axle.

[0029] According to two aspects of the present invention, a braking energy recovery strategy simulation device is provided, the braking energy recovery strategy simulation device comprising:

[0030] A first confirmation module is used to confirm vehicle parameters related to the energy recovery strategy, as well as input signals and output signals of the control strategy model;

[0031] The first calculation module is used to calculate the total braking force and braking intensity;

[0032] The second confirmation module is used to determine the recovery factor and the recovery mark;

[0033] The second calculation module is used to calculate the ideal curve allocation ratio;

[0034] The third calculation module is used for calculating the motor torque according to the dynamic equation when the motor is driven or the recovery flag is false, and the energy recovery model is only responsible for transmitting the result. When the recovery flag is true, recovery is performed and the negative torque demand torque is output;

[0035] A fourth calculation module, used for calculating the front axle brake pressure according to the ideal curve distribution ratio;

[0036] A fifth calculation module, used for calculating the rear axle brake pressure according to the ideal curve distribution ratio;

[0037] The output module is used to output the result based on the current motor demand torque.

[0038] According to three aspects of the present invention, there is provided an electronic device, comprising: a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus;

[0039] A computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the braking energy recovery strategy simulation method.

[0040] According to four aspects of the present invention, a computer-readable storage medium is provided, comprising: a computer program executable by an electronic device is stored therein, and when the computer program runs on the electronic device, the electronic device executes the steps of the braking energy recovery strategy simulation method.

[0041] Through the above scheme, the following beneficial technical effects are obtained:

[0042] At present, the energy recovery strategy is relatively simple, which is reflected in the excessive anti-drag torque when braking is required, resulting in large errors in the simulation results. The strategy model of this application combines multiple influencing factors to allow the motor to participate in braking as much as possible under the premise of safe braking intensity to reduce mechanical braking; secondly, the power supply SOC situation is considered to limit the energy recovery capability; thirdly, the front and rear axle braking force distribution is completed based on the ideal front and rear axle braking force distribution curve, and the distribution of motor and mechanical braking is considered; in summary, the problem of excessive anti-torque error caused by the overly simple simulation strategy is solved, the correction of the anti-drag torque intensity is completed, and the simulation load response is closer to the anti-drag load response of real users. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a flow chart of a braking energy recovery strategy simulation method provided by one or more embodiments of the present invention;

[0044] Figure 2 is a flowchart of a fourth calculation operation in the braking energy recovery strategy simulation method provided by one or more embodiments of the present invention;

[0045] Figure 3 is a flowchart of a fifth calculation operation in a braking energy recovery strategy simulation method provided by one or more embodiments of the present invention;

[0046] Figure 4 is a flow chart of a braking energy recovery strategy simulation method provided by one or more embodiments of the present invention;

[0047] Figure 5 is a diagram showing the relationship between mechanical braking and motor braking provided by one or more embodiments of the present invention;

[0048] Figure 6 is an overall structural diagram of a control strategy model provided by one or more embodiments of the present invention;

[0049] Figure 7 is a model structure diagram of a control strategy part provided by one or more embodiments of the present invention;

[0050] Figure 8 is a schematic diagram of input signals of a control strategy provided by one or more embodiments of the present invention;

[0051] Fig. 9 is a schematic diagram of output signals of a control strategy provided by one or more embodiments of the present invention;

[0052] Fig.10 is a strategy model diagram for calculating braking force and braking intensity provided by one or more embodiments of the present invention;

[0053] Fig.11 is a strategy model diagram for energy recovery enabling and recovery coefficient calculation provided by one or more embodiments of the present invention;

[0054] Fig.12 is a strategy model diagram for calculating the ideal braking force front axle distribution ratio provided by one or more embodiments of the present invention;

[0055] Fig.13 is a strategy model diagram for calculating the motor required torque provided by one or more embodiments of the present invention;

[0056] Fig.14 is a strategy model diagram for calculating the front axle brake pressure provided by one or more embodiments of the present invention;

[0057] Fig.15 is a strategy model diagram for calculating rear axle brake pressure provided by one or more embodiments of the present invention;

[0058] Fig.16 is a structural diagram of a braking energy recovery strategy simulation device provided by one or more embodiments of the present invention;

[0059] Fig.17 is a structural diagram of an electronic device provided by one or more embodiments of the present invention. DETAILED DESCRIPTION

[0060] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0061] To solve the above problems, the present invention provides a universal energy recovery strategy method that tries to fit the actual anti-drag working conditions of pure electric vehicle users. In order to ensure that the load response simulation is as accurate as possible, this method takes into account a variety of factors, and simulates the actual pure electric vehicle model to verify the accuracy of the simulated load response. The main factors considered in this braking energy recovery strategy include braking intensity, power supply SOC, ideal front and rear axle braking force distribution, battery charging and discharging efficiency, motor efficiency, driving speed, etc.

[0062] When an electric vehicle coasts to slow down or applies the brakes to slow down, the drive motor changes from an electric state to a power generation state. The motor rotor cuts the magnetic lines of flux to generate electrical energy, which is stored in the power battery through the inverter to achieve energy recovery, thereby improving the working efficiency of the electric vehicle.

[0063] Figure 1 FIG. 1 is a flow chart showing a method for simulating a braking energy recovery strategy provided by one or more embodiments of the present invention. Figure 1 , the braking energy recovery strategy simulation method includes the following operating steps:

[0064] S11, confirming vehicle parameters related to the energy recovery strategy, as well as input signals and output signals of the control strategy model.

[0065] S12, calculating the total braking force and braking intensity.

[0066] S13, determine the recovery factor and recovery symbol.

[0067] S14, calculating the ideal curve distribution ratio.

[0068] S15, when the motor is driven, or the recovery flag is false, the motor torque is calculated according to the dynamic equation, and the energy recovery model is only responsible for transmitting the result. When the recovery flag is true, recovery is performed and the negative torque demand torque is output.

[0069] S16, calculating the front axle braking pressure according to the ideal curve distribution ratio.

[0070] S17, calculating the rear axle braking pressure according to the ideal curve distribution ratio.

[0071] S18, outputting the result based on the current motor required torque.

[0072] A simulation method for a pure electric vehicle braking energy recovery strategy includes the following processes:

[0073] Confirm the vehicle parameters related to the energy recovery strategy (the applicable vehicle model for this application is a front-wheel drive pure electric vehicle), including: wheelbase (mm), frontal area (m 2 ), distance from center of mass to front axle (mm), curb mass (kg), fully loaded mass (kg), tire rolling radius (mm), drag coefficient, rolling resistance coefficient.

[0074] Confirm the input signals of the control strategy model, including: battery SOC, front axle braking coefficient, rear axle braking coefficient, braking pressure, main reduction ratio, vehicle load signal, mechanical transmission efficiency, motor maximum driving torque, motor maximum recovery torque, and vehicle speed.

[0075] Confirm the output signals of the control strategy model, including: braking intensity, braking distribution coefficient, front axle braking pressure, motor required torque, rear axle braking pressure, and total braking force.

[0076] Calculate the total braking force and braking intensity: F b =(k bf +k br )×2×Pa÷r

[0077] k bf is the front axle braking coefficient, k br is the rear axle braking coefficient; Pa is the braking pressure; r is the rolling radius of the vehicle; the braking intensity z is: z = F b ÷m÷g, m is the weight of the vehicle, g is the acceleration due to gravity.

[0078] Determine the recovery coefficient (limiting the recovery capacity) and the recovery flag (whether energy recovery is allowed): when the SOC is greater than or equal to 90% and less than 95%, the recovery coefficient ranges from 1 to 0.1; when the SOC is greater than 95% and less than 100%, the recovery coefficient ranges from 0.1 to 0; when the speed is greater than 7km / h and the braking pressure is greater than 0, energy recovery is allowed, and the recovery flag is true, otherwise it is false.

[0079] The ideal curve distribution ratio can ensure that the front and rear wheels are locked at the same time and no side slip occurs.

[0080] Ideal curve distribution ratio calculation: When the front and rear wheels of the vehicle are locked at the same time during braking, the relationship curve between the front and rear axle braking forces is called the ideal braking force distribution curve. The calculation curve equation is as follows:

[0081]

[0082] F b =F bf +F br

[0083]

[0084] Where: F bf is the front axle braking force, F br is the rear axle braking force, G is the vehicle gravity, h is the height of the vehicle's center of mass, b is the distance from the vehicle's center of mass to the center line of the rear axle, and L is the vehicle's wheelbase.

[0085] Motor demand torque calculation: When the motor is driven, or the recovery flag is false, the motor torque is calculated according to the dynamic equation, and the energy recovery model is only responsible for transmitting the result (the input load signal, that is, the demand percentage of the motor's maximum torque, is directly multiplied by the maximum motor torque to output the demand torque); when the recovery flag is true, recovery is performed and the negative torque demand torque is output. The specific recovery torque calculation process is as follows:

[0086] When the braking intensity z≥0.6, it is judged as sudden deceleration, and the motor does not participate in braking at this time; when the braking intensity z>0.13 and ≤0.6, both the motor and the mechanical part participate in braking, and when z<0.13, only the motor participates in braking.

[0087] The recovery factor is related to the battery charge i. When the SOC is 100%, the motor does not need to participate in braking, and the recovery factor is 0, which means that it is not allowed to charge the battery. When the SOC is 90%, the motor brakes 100% according to the braking demand assigned to it, and the recovery factor is 1. The motor will charge the battery when it participates in braking. In other words, when the SOC is from 90-100, the motor's braking capacity goes from 1 to 0. When the SOC is 100%, the braking force demand allocated to the front drive is provided by the brake disc and is not allocated to the motor.

[0088] Calculation of front axle braking pressure: When the braking intensity is lower than 0.6, the front axle mechanical braking force is the front axle braking force minus the motor braking force; when the braking intensity is greater than 0.6, the front axle mechanical force is the front axle braking force under the ideal curve distribution of the total braking force; based on the above front axle mechanical braking forces, the front axle braking pressure is calculated using the vehicle rolling radius and the front axle braking coefficient.

[0089] Calculation of rear axle brake pressure: When the brake intensity is less than 0.13, there is no mechanical brake force on the rear axle (high-efficiency energy recovery). When the brake intensity is greater than 0.13, the rear axle mechanical brake force is calculated according to the ideal distribution curve of the total brake force. Based on the above rear axle mechanical brake force, the rear axle brake pressure is calculated by the vehicle rolling radius and rear axle brake coefficient.

[0090] Based on the current motor demand torque output results, load response simulation with very small error can be achieved, and the error value of the damage evaluation mark is about 5%.

[0091] By Figure 1 The execution process shown replaces the complex vehicle real braking energy recovery strategy with a universal braking energy recovery strategy, achieving good results.

[0092] In addition, the process parameters are optimized and developed based on a certain model, which means that Figure 1 It shows that the simulation method can be applied to different vehicle models and has a wider range of uses.

[0093] Figure 2 FIG. 4 is a flowchart showing the fourth calculation step in the braking energy recovery strategy simulation method provided by one or more embodiments of the present invention. Figure 2 , calculate the front axle brake pressure according to the ideal curve distribution ratio, including:

[0094] S21, when the braking intensity is lower than the first intensity threshold, the front axle mechanical braking force is the front axle braking force minus the motor braking force.

[0095] S22, when the braking intensity is greater than the first intensity threshold, the front axle mechanical force is the front axle braking force under the ideal curve distribution of the total braking force.

[0096] When the braking intensity is lower than 0.6, the front axle mechanical braking force is the front axle braking force minus the motor braking force. When the braking intensity is greater than 0.6, the front axle mechanical force is the front axle braking force under the ideal curve distribution of the total braking force. Combining the above front axle mechanical braking forces, the front axle braking pressure is calculated through the vehicle rolling radius and the front axle braking coefficient.

[0097] Figure 3 FIG. 5 is a flowchart showing the fifth calculation step in the braking energy recovery strategy simulation method provided by one or more embodiments of the present invention. Figure 3 , according to the ideal curve distribution ratio, calculate the rear axle brake pressure, including:

[0098] S31, when the braking intensity is less than the second intensity threshold, the rear axle has no mechanical braking force.

[0099] S32, when the braking intensity is greater than the second intensity threshold, the rear axle mechanical braking force is calculated according to the ideal distribution curve of the total braking force.

[0100] When the braking intensity is less than 0.13, there is no mechanical braking force on the rear axle (high-efficiency energy recovery). When the braking intensity is greater than 0.13, the rear axle mechanical braking force is calculated according to the ideal distribution curve of the total braking force. Based on the above rear axle mechanical braking force, the rear axle braking pressure is calculated by the vehicle rolling radius and the rear axle braking coefficient.

[0101] Figure 4 FIG. 1 is a flow chart showing a method for simulating a braking energy recovery strategy provided by one or more embodiments of the present invention. Figure 4 ,The simulation method for braking energy recovery strategy includes the following steps:

[0102] S41, input and output of control strategy.

[0103] S42, calculation of total braking force and braking intensity.

[0104] S43, energy recovery enabling and recovery coefficient calculation.

[0105] S44, calculation of ideal curve front axle distribution ratio.

[0106] S45, calculation of motor required torque.

[0107] S46, front axle brake pressure calculation.

[0108] S47, rear axle brake pressure calculation.

[0109] During the electric motor braking process of electric vehicles, the torque of the driving motor is transmitted to the driving wheels through the transmission shaft to reduce the vehicle speed, and the electric energy generated by the reverse drag is transmitted to the power battery after passing through the power conversion device. When the vehicle is in motion, the distribution of braking force during braking has an important impact on the performance of the braking system. When a small braking intensity is required, pure motor braking can be performed by releasing the accelerator pedal. At this time, the braking force comes entirely from the driving wheels; when a larger braking intensity or emergency braking is required, a combination of mechanical braking and motor braking can be performed. At this time, both the driving wheels and the driven wheels can provide braking force. See Figure 5 shown.

[0110] When distributing the braking force, considering that the motor braking can only occur on the driving wheels, the braking force should be distributed more on the driving shaft to ensure more efficient recovery of braking energy. At the same time, the energy recovery effect of the car is also related to many factors, such as battery SOC, battery charging and discharging efficiency, motor efficiency, driving speed, road adhesion coefficient, braking intensity, etc.

[0111] Before determining the front and rear axle braking force distribution, we must first analyze the normal reaction force on the front and rear wheels when the vehicle brakes. When the vehicle brakes on a horizontal road, the normal forces on the front and rear wheels are: Z1, rear wheel normal force F Z2 The normal reaction force is calculated as follows:

[0112]

[0113] Where L is the wheelbase of the vehicle; G is the weight of the vehicle; b is the distance from the center of mass of the vehicle to the centerline of the rear axle; a is the distance from the center of gravity of the vehicle to the front axle; m is the mass of the vehicle; h is the distance from the center of mass of the vehicle to the centerline of the rear ... g is the height of the center of mass of the car; du / dt is the deceleration of the car when braking, let du / dt = z g , called z g For the braking strength.

[0114] When the braking force of the car brake is sufficient, three situations will occur during the braking process, namely:

[0115] (1) The front wheels lock and skid first, then the rear wheels lock and skid;

[0116] (2) The rear wheels lock and skid first, then the front wheels lock and skid;

[0117] (3) The front and rear wheels lock and skid simultaneously.

[0118] Among them, situation (1) is a stable working condition, but the steering ability is lost during braking, and the adhesion condition is not fully utilized; in situation (2), the rear axle is locked and dragged first, which is an unstable working condition, and the adhesion utilization rate is also low; while situation (3) can avoid the rear axle side slip, and the steering wheel will only make the car lose steering ability under the maximum braking intensity, and the adhesion condition is better utilized. The condition for the front and rear wheels to lock and drag at the same time is that the sum of the front and rear wheel braking forces is equal to the adhesion force, and the front and rear wheel brake forces are respectively equal to their respective adhesion forces, that is:

[0119]

[0120] In the formula, F bf F is the front wheel braking force of the vehicle; br Provide braking force for the rear wheels of the vehicle; is the road friction coefficient. Eliminate the variable The following formula is obtained, in which the relationship between the front and rear wheel braking forces is the braking force distribution ratio under ideal conditions, and the corresponding front and rear wheel braking force relationship curve is called the ideal front and rear wheel braking force distribution curve.

[0121]

[0122] By deduction, the calculation formula of the braking force distribution coefficient β is obtained:

[0123]

[0124] F b =Fbf +F br

[0125]

[0126] Where: F bf is the front axle braking force; F br is the rear axle braking force; G is the vehicle gravity; h is the height of the vehicle's center of mass; b is the distance from the vehicle's center of mass to the center line of the rear axle; L is the vehicle's wheelbase; F b is the total braking force.

[0127] The ideal braking force distribution strategy first ensures the driving safety of the vehicle during braking. Its expectation is to reasonably distribute the braking force of the vehicle axles according to the ideal braking force distribution curve when the vehicle brakes, so that the vehicle can recover energy as much as possible under the optimal front and rear braking force distribution conditions. During low-intensity braking, the braking force required by the vehicle can be met by the braking force generated by the motor alone. When the braking intensity gradually increases and the braking force provided by the motor is insufficient to meet the current required braking force, the two braking forces work together at this time, and the motor recovers energy according to the maximum braking force it can generate.

[0128] The ideal braking force distribution control strategy can ensure that the vehicle has good stability during braking and fully considers the ground adhesion conditions. However, when distributing braking force, the current strategy requires accurate detection of the normal loads on the front and rear axles of the vehicle, which is difficult to achieve with a controller and requires the corresponding actuator, making it technically difficult to develop.

[0129] When braking, the braking force of the front and rear wheels should be distributed to the drive wheels as much as possible while ensuring safety, and the braking force of the front and rear axles should be distributed according to the ideal braking force curve.

[0130] When the braking intensity is small (i.e. the braking intensity is lower than 0.15), the braking force generated by the motor braking is sufficient to meet the braking force requirement at this time. All the braking force can be distributed to the front axle to maximize the recovery efficiency, that is, motor braking is given priority, and when the motor braking is insufficient, the front axle mechanical braking is used to compensate.

[0131] When the braking intensity is medium (i.e. the braking intensity is between 0.15 and 0.7), using only the front axle brake may not meet the current braking force requirements or guarantee safety, and the rear axle mechanical brake needs to intervene, and the front and rear axles are distributed according to the ideal braking force curve. In this case, the participation of the motor brake must be ensured first, and the front axle will be given priority for motor braking. When the motor braking is insufficient, the front axle mechanical brake will compensate, and the rear axle will be completely provided by the rear axle mechanical brake.

[0132] During emergency braking (i.e. braking intensity exceeds 0.7), since the vehicle's braking force demand is very high, in order to ensure vehicle body stability, the braking force distribution of the front and rear axles is carried out according to the ideal braking force curve, and at this time the front and rear axles are all provided with braking force by mechanical brakes.

[0133] When designing an electric vehicle braking control system, in addition to considering the above-mentioned braking situations, the battery SOC value also needs to be considered. When a pure electric vehicle is charged normally, the first 90% of the rated capacity of the battery is the fast charging stage, at which time the charging current and voltage reach the maximum allowable value of the design; after exceeding 90% of the rated capacity, in order to ensure that the impact on battery performance is as small as possible, the battery switches to the trickle charging stage, at which time the current and voltage will decrease as the capacity gradually increases until it drops to 0 when fully charged. When braking energy is recovered, the impact on battery performance also needs to be considered. Charging when the battery SOC value is high will shorten the battery life, and energy recovery is not suitable. Therefore, based on the battery performance parameters, when the battery SOC is higher than 90%, the recovery capacity of the motor is gradually reduced until the energy recovery is stopped when the SOC reaches 95%.

[0134] The entire control strategy consists of three parts: input signal processing, control strategy, and output signal processing. The control strategy model is as follows: Figure 6 shown.

[0135] Among them, the control strategy part is designed into the following functional blocks based on the research and analysis of the above contents, namely:

[0136] 1) Calculation of total braking force and braking intensity;

[0137] 2) Energy recovery enablement and recovery factor calculation;

[0138] 3) Calculation of the ideal curve front axle allocation ratio;

[0139] 4) Calculation of motor required torque;

[0140] 5) Calculation of front axle brake pressure;

[0141] 6) Calculation of rear axle brake pressure.

[0142] The control strategy model is as follows: Figure 7 shown.

[0143] The input signals of the control strategy are shown in Table 1:

[0144] Table 1 Input signals of control strategy

[0145]

[0146] The input signal processing part mainly converts the data type of the input signal, converts the input signal data type provided by the CRUISE model into the data type that matches the Simulink model; and limits the value range of certain signals, such as: the value range of the battery SOC is 0-100, the value range of the load signal is 0-100, etc. Figure 8 shown.

[0147] The input signals of the control strategy are shown in Table 2:

[0148] Table 2 Input signals of control strategy

[0149]

[0150]

[0151] The input signal processing part mainly converts the data type of the input signal, converts the input signal data type provided by the CRUISE model into the data type that matches the Simulink model; and limits the value range of certain signals, such as: the value range of the battery SOC is 0-100, the value range of the load signal is 0-100, etc. Fig. 9 shown.

[0152] The output signal of the control strategy is shown in Table 3.

[0153] Table 3 Output signals of control strategy

[0154]

[0155] The output signal processing part mainly converts the data type of the input signal, and converts the output signal data type provided by the Simulink model into the data type matching the CRUISE model, such as Fig.10 shown.

[0156] The total braking force F required by the vehicle is calculated by the following formula b :

[0157] F b =(k bf +k br )×2×Pa÷r

[0158] Where: k bf is the front axle braking coefficient; k br is the rear axle braking coefficient; Pa is the braking pressure; r is the vehicle rolling radius, which is 0.38155m.

[0159] The vehicle's braking strength z is calculated using the following formula:

[0160] z=F b÷m÷g

[0161] Where: m is the mass of the vehicle, which is 2200 kg; g is the acceleration due to gravity, which is 9.8 m / s 2 .

[0162] The strategy model for calculating braking force and braking intensity is as follows: Fig.10 shown.

[0163] The recovery factor is determined by looking up the table based on the battery SOC. When the SOC is higher than 90%, the recovery factor gradually decreases from 1 until it decreases to 0 when the SOC is 95%.

[0164] When the vehicle speed exceeds a certain value, the brake is pressed (i.e. the brake pressure is greater than 0Pa), and the battery is allowed to recover (i.e. the recovery coefficient is greater than 0), then the energy recovery enable flag is set to TRUE, otherwise it is set to FALSE.

[0165] In addition, in order to achieve simulation comparison with and without energy recovery, an energy recovery function switch signal is set. The energy recovery function can be started / turned off by changing the value of this signal.

[0166] The strategy model for energy recovery enablement and recovery factor calculation is as follows: Fig.11 shown.

[0167] When the front and rear wheels of a vehicle are locked at the same time during braking, the relationship curve between the front and rear axle braking forces is called the ideal braking force distribution curve. The calculation formula of the braking force distribution coefficient β can be inferred from the following formula:

[0168]

[0169] F b =F bf +F br

[0170]

[0171] Where: F bf is the front axle braking force; F br is the rear axle braking force; G is the vehicle gravity; h is the height of the vehicle's center of mass; b is the distance from the vehicle's center of mass to the center line of the rear axle; L is the vehicle's wheelbase.

[0172] The strategy model for calculating the ideal braking force front axle distribution ratio is as follows: Fig.12 shown.

[0173] When the energy recovery function is turned off, or the motor is in driving state, or energy recovery is not enabled, the required torque of the motor is calculated based on the throttle opening and the maximum torque capacity of the motor.

[0174] After energy recovery is enabled, the following situations occur:

[0175] 1) Braking intensity ≥ 0.7, at this time the braking force allocated to the motor is 0, the motor braking is turned off, and no energy recovery is performed;

[0176] 2) Braking intensity <0.7 and ≥0.15, at this time, the front axle is braked by mechanical and electric motors, and the electric motor distributes the braking force according to the maximum recovery capacity;

[0177] 3) Braking intensity < 0.15. At this time, the vehicle braking force is completely provided by the front axle mechanical and electric motor combined braking, and the motor distributes the braking force according to the maximum recovery capacity.

[0178] The strategy model for calculating the motor required torque is as follows: Fig.13 shown.

[0179] When the braking intensity is lower than 0.7, the front axle mechanical braking force is the difference between the front axle braking force and the electric brake force, and the front axle mechanical braking force compensates for the insufficient electric brake force.

[0180] When the braking intensity is higher than 0.7, the motor braking is turned off. At this time, the front axle mechanical braking force is the front axle braking force distributed according to the ideal braking force distribution curve.

[0181] The front axle brake pressure can be calculated based on the allocated front axle mechanical braking force, the vehicle's rolling radius and the front axle braking coefficient.

[0182] The strategy model for calculating the front axle brake pressure is as follows: Fig.14 shown.

[0183] When the braking intensity is less than 0.15, the rear axle braking force distribution is 0.

[0184] When the braking intensity is greater than 0.15, the rear axle braking force is distributed according to the ideal braking force curve.

[0185] The rear axle brake pressure can be calculated based on the distributed rear axle braking force, the vehicle's rolling radius and the rear axle braking coefficient.

[0186] The strategy model for calculating the rear axle brake pressure is as follows: Fig.15 shown.

[0187] like Fig.16 As shown, the present invention also provides a braking energy recovery strategy simulation device, comprising:

[0188] The first confirmation module 161 is used to confirm the vehicle parameters related to the energy recovery strategy, as well as the input signal and output signal of the control strategy model;

[0189] The first calculation module 162 is used to calculate the total braking force and the braking intensity.

[0190] The second confirmation module 163 is used to determine the recovery coefficient and the recovery mark.

[0191] The second calculation module 164 is used to calculate the ideal curve allocation ratio.

[0192] The third calculation module 165 is used to calculate the motor torque according to the dynamic equation when the motor is driven or the recovery flag is false. The energy recovery model is only responsible for transmitting the result. When the recovery flag is true, recovery is performed and a negative torque demand torque is output.

[0193] The fourth calculation module 166 is used to calculate the front axle braking pressure according to the ideal curve distribution ratio.

[0194] The fifth calculation module 167 is used to calculate the rear axle braking pressure according to the ideal curve distribution ratio.

[0195] The output module 168 is configured to output a result based on the current motor demand torque.

[0196] It is worth noting that although only some basic functional modules are disclosed in the embodiments of the present invention, it does not mean that the composition of the present system is limited to the above basic functional modules. On the contrary, what the present embodiment wants to express is that on the basis of the above basic functional modules, those skilled in the art can arbitrarily add one or more functional modules in combination with the prior art to form an infinite number of embodiments or technical solutions. In other words, the present system is open rather than closed. Just because the present embodiment only discloses individual basic functional modules, it cannot be considered that the protection scope of the claims of the present invention is limited to the disclosed basic functional modules. At the same time, for the convenience of description, the above devices are described in terms of functions and are described separately in various units and modules. Of course, when implementing the present invention, the functions of each unit and module can be implemented in the same or one or more software and / or hardware.

[0197] like Fig.17 As shown, the present invention also provides an electronic device, comprising: a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other through the communication bus; a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the braking energy recovery strategy simulation method.

[0198] Fig.17 Schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. Fig.17 The electronic device provided in the embodiment of the present invention includes: one or more processors 1710 and a memory 1720; the processor 1710 in the electronic device may be one or more, Fig.17A processor 1710 is taken as an example; the memory 1720 is used to store one or more programs; the one or more programs are executed by the one or more processors 1710, so that the one or more processors 1710 implement the braking energy recovery strategy simulation method as described in any one of the embodiments of the present invention.

[0199] The electronic device may further include: an input device 1730 and an output device 1740 .

[0200] The processor 1710, memory 1720, input device 1730 and output device 1740 in the electronic device can be connected via a bus or other means. Fig.17 The example of connecting through bus is taken in the following.

[0201] The memory 1720 in the electronic device is a computer-readable storage medium that can be used to store one or more programs, which can be software programs, computer executable programs and modules, such as the program instructions / modules corresponding to the full-link test method for voice vehicle control provided in the embodiment of the present invention. The processor 1710 executes various functional applications and data processing of the electronic device by running the software programs, instructions and modules stored in the memory 1720, that is, implements the braking energy recovery strategy simulation method in the above method embodiment.

[0202] The memory 1720 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the electronic device, etc. In addition, the memory 1720 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device. In some instances, the memory 1720 may further include a memory remotely arranged relative to the processor 1710, and these remote memories may be connected to the device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0203] The input device 1730 may be used to receive input digital or character information and generate key signal input related to user settings and function control of the electronic device. The output device 1740 may include a display device such as a display screen.

[0204] The present invention also provides a computer-readable storage medium storing a computer program executable by an electronic device, and when the computer program runs on the electronic device, the electronic device executes the steps of the braking energy recovery strategy simulation method.

[0205] Specifically, the computer storage medium of the embodiment of the present invention can adopt any combination of one or more computer-readable media. The computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of computer-readable storage media include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present embodiment, the computer-readable storage medium can be any tangible medium containing or storing a program, which can be used by an instruction execution system, device or device or used in combination with it.

[0206] The present invention also provides a vehicle, wherein the vehicle is provided with the braking energy recovery strategy simulation device as described above.

[0207] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A braking energy recovery strategy simulation method, characterized in that: The braking energy recovery strategy simulation method comprises: Confirm vehicle parameters related to energy recovery strategy, as well as input and output signals of control strategy model; Calculate total braking force and braking intensity; Determine the recovery factor and recovery symbol; Calculate the ideal curve distribution ratio; When the motor is driven, or the recovery flag is false, the motor torque is calculated according to the dynamic equation, and the energy recovery model is only responsible for transmitting the result. When the recovery flag is true, recovery is performed and the negative torque demand torque is output; Calculate the front axle brake pressure according to the ideal curve distribution ratio; Calculate the rear axle brake pressure according to the ideal curve distribution ratio; The torque output result is based on the current motor demand.

2. The method according to claim 1, characterized in that: The vehicle strategies related to the energy recovery strategy include: wheelbase, frontal area, distance from center of mass to front axle, curb weight, fully loaded mass, tire rolling radius, drag coefficient, and rolling resistance coefficient.

3. The method according to claim 1, characterized in that The input signals of the control strategy model include: battery SOC, front axle braking coefficient, rear axle braking coefficient, braking pressure, main reduction ratio, vehicle load signal, mechanical transmission efficiency, maximum motor driving torque, maximum motor recovery torque, and vehicle speed.

4. The method according to claim 1, characterized in that: The output signals of the control strategy model include: braking intensity, braking distribution coefficient, front axle braking pressure, motor required torque, rear axle braking pressure, and total braking force.

5. The method according to claim 1, characterized in that Calculation of total braking force and braking intensity includes: The total braking force is calculated according to the following formula: F b =(k bf +k br )×2×Pa÷r Among them, k bf is the front axle braking coefficient, k br is the rear axle braking coefficient, Pa is the braking pressure, and r is the vehicle rolling radius.

6. The method according to claim 1, characterized in that Calculation of total braking force and braking intensity includes: The braking strength is calculated according to the following formula: z=F b ÷m÷g Among them, F b is the total braking force, m is the vehicle weight, and g is the acceleration due to gravity.

7. The method according to claim 1, characterized in that Calculating the ideal curve allocation ratio includes: When the front and rear wheels of the vehicle are locked simultaneously during braking, the ideal braking force distribution curve is calculated according to the following formula: Among them, F bf is the front axle braking force, F br Braking force for the rear axle.

8. A braking energy recovery strategy simulation device, characterized in that: The braking energy recovery strategy simulation device comprises: A first confirmation module is used to confirm vehicle parameters related to the energy recovery strategy, as well as input signals and output signals of the control strategy model; The first calculation module is used to calculate the total braking force and braking intensity; The second confirmation module is used to determine the recovery factor and the recovery mark; The second calculation module is used to calculate the ideal curve allocation ratio; The third calculation module is used for calculating the motor torque according to the dynamic equation when the motor is driven or the recovery flag is false, and the energy recovery model is only responsible for transmitting the result. When the recovery flag is true, recovery is performed and the negative torque demand torque is output; A fourth calculation module, used for calculating the front axle brake pressure according to the ideal curve distribution ratio; A fifth calculation module, used for calculating the rear axle brake pressure according to the ideal curve distribution ratio; The output module is used to output the result based on the current motor demand torque.

9. An electronic device, characterized in that: include: A processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of any one of the methods described in claims 1 to 7.

10. A computer-readable storage medium, characterized in that: It stores a computer program executable by an electronic device, and when the computer program runs on the electronic device, the electronic device executes the steps of the method described in any one of claims 1 to 7.

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