Vehicle braking control method, system, equipment and medium

Abstract

The invention discloses a vehicle braking control method, system and device and a medium. The method comprises the steps that the driving state of a vehicle and state parameters corresponding to the driving state are obtained; obtaining comfortable pressure buildup demand parameters of the vehicle based on the driving state and the state parameters; initial target electric cylinder brake pressure of the vehicle is obtained, and target electric cylinder brake pressure of the vehicle is obtained based on the initial target electric cylinder brake pressure and the comfortable pressure building demand parameters; and controlling an electric cylinder of the vehicle to brake based on the target electric cylinder brake pressure. The problem that an existing brake-by-wire system conducts vehicle braking only according to the braking force applied by a driver and the pedal stroke, different braking requirements of the driver cannot be met, and consequently the driving experience of the driver is poor is solved.

Description

Background Art

[0002] With the development of vehicle technology, drivers have higher and higher requirements for vehicle driving experience. The existing vehicle braking is that when the driver steps on the brake pedal, the vehicle's wire control system (Integrated Brake Control Unit, IBCU) directly controls the braking according to the braking force and pedal travel applied by the driver. However, braking the vehicle only based on the braking force and pedal travel applied by the driver cannot meet the driver's different braking needs, resulting in a poor driving experience for the driver. Summary of the invention

[0003] In order to overcome the problem that the existing brake-by-wire system only brakes the vehicle according to the braking force and pedal travel applied by the driver and cannot meet the driver's different braking needs, resulting in a poor driving experience for the driver, the present application provides a vehicle braking control method, system, device and medium.

[0004] In a first aspect, in order to solve the above technical problems, the present application provides a vehicle braking control method, comprising:

[0005] Obtaining the driving state of the vehicle and state parameters corresponding to the driving state;

[0006] Obtaining a comfortable pressure building requirement parameter of the vehicle based on the driving state and state parameters;

[0007] Acquiring an initial target electric cylinder brake pressure of the vehicle, and obtaining a target electric cylinder brake pressure of the vehicle based on the initial target electric cylinder brake pressure and a comfortable pressure building requirement parameter;

[0008] The electric cylinder of the vehicle is controlled to brake based on the target electric cylinder brake pressure.

[0009] In a second aspect, the present application also provides a vehicle braking control system, comprising:

[0010] An acquisition module, used to acquire the driving state of the vehicle and state parameters corresponding to the driving state;

[0011] A first obtaining module is used to obtain a comfortable pressure building requirement parameter of the vehicle based on the driving state and the state parameter;

[0012] The second obtaining module is used to obtain the initial target electric cylinder brake pressure of the vehicle, and obtain the target electric cylinder brake pressure of the vehicle based on the initial target electric cylinder brake pressure and the comfortable pressure building requirement parameter;

[0013] The brake module is used to control the electric cylinder of the vehicle to brake based on the target electric cylinder brake pressure.

[0014] In a third aspect, the present application also provides a computing device, including a memory, a processor, and a program stored in the memory and running on the processor, and when the processor executes the program, the steps of a vehicle braking control method as described above are implemented.

[0015] In a fourth aspect, the present application also provides a computer-readable storage medium, in which instructions are stored. When the instructions are executed on a terminal device, the terminal device executes the steps of a vehicle braking control method.

[0016] The beneficial effects of the present application are as follows: first, by acquiring the driving state and corresponding state parameters of the vehicle, and obtaining the comfortable pressure building requirement parameters of the vehicle based on the driving state and the state parameters. Then, the initial target electric cylinder brake pressure of the vehicle is acquired, and the target electric cylinder brake pressure of the vehicle is obtained based on the initial target electric cylinder brake pressure and the comfortable pressure building requirement parameters, and the electric cylinder of the vehicle is controlled to brake based on the target electric cylinder brake pressure. In this way, when the vehicle brakes, the driving state and state parameters of the vehicle are taken into consideration to obtain the target brake pressure that meets the driver's comfortable pressure building requirement for the vehicle to brake the vehicle, which can meet the driver's current braking needs, thereby improving the driver's driving experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the pressure build-up curve for the IBCU product equipped with Yilong Valve;

[0018] Figure 2 Based on Figure 1 The pressure build-up situation of the IBCU product of Yilong Valve is the pressure build-up curve after reducing the pressure build-up slope;

[0019] Figure 3 A schematic flow chart of a vehicle braking control method according to an exemplary embodiment of the present application;

[0020] Figure 4 This is a flow chart of a vehicle braking control method provided by the application in an exemplary embodiment of the present application;

[0021] Figure 5 1 is a schematic structural diagram of a hydraulic circuit of a wire control brake system for a vehicle brake control method in an exemplary embodiment of the present application;

[0022] Figure 6 The figure is a schematic diagram of the structure of a vehicle braking control system showing an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0023] The following examples are provided to further explain and supplement the present application and do not constitute any limitation to the present application.

[0024] In the prior art, the IBCU brake-by-wire system has the advantage of fast wheel cylinder pressure build-up, but it also means that the electric cylinder pressure is prone to overshoot; once the pressure build-up speed is too fast and exceeds the flow rate limit of the inlet valve, a large pressure difference is easily formed between the electric cylinder and the wheel cylinder. Excessive pressure difference will cause the brake fluid and valve to collide, generating vibration, noise and harshness, exacerbating users' complaints about vehicle NVH (Noise, Vibration, Harshness).

[0025] In the IBCU, for the inlet valve, the linear control current range of the inlet valve is usually required to be sufficient, generally requiring a linear range of 60mA, and the linear control flow range must also be sufficient, at 0-0.4L / min, so that the single-wheel pressure building request under each pressure building slope can be better realized; at the same time, factors such as material cost must also be considered. Therefore, the aperture of the inlet valve is generally not designed to be large enough. Taking the domestically produced Yilong inlet valve (hereinafter referred to as: Yilong valve) currently in mass production on the market as an example, it has a good linear control current range and a good linear control flow range. However, its aperture is small, which results in the flow of the Yilong valve being only 2 / 3 of the Bosch inlet valve or even smaller under the same pressure difference. Under the same pressure difference, the smaller flow means that for some vehicles with calipers with large liquid storage, it is difficult to achieve the effect of rapid pressure building of the wheel cylinder without overshooting the electric cylinder pressure, especially for small and fast target pressure building targets, the effect is poor.

[0026] like Figure 1 As shown in the figure, the test object is a test vehicle equipped with the IBCU product of Yilong Valve; the test conditions are: flat ground, the vehicle is stationary, P gear, the brake pedal is pressed quickly, the target pressure of pressure building is 10bar (after restriction), and the pressure building slope limit is 160bar / s (after restriction). It can be seen that for such a small pressure building, the fixed slope pressure building slope limit of 160bar / s is still not small enough, and the pressure of the electric cylinder and the wheel cylinder has an unacceptable overshoot, which brings additional NVH complaints. If this overshoot is to be improved, the target pressure building slope must be reduced.

[0027] like Figure 2 As shown in the figure, after reducing the pressure building slope to 30 bar / s, the electric cylinder pressure and wheel cylinder pressure basically did not overshoot. It can be seen that a small fixed slope pressure limit has a significant improvement on the electric cylinder pressure overshoot and NVH, but the pressure building rate of 30 bar / s is too slow. Moreover, it only solves the pressure building overshoot problem of 0-10 bar, and cannot solve the pressure building overshoot problem of smaller target pressures. On the contrary, the pressure building rate for larger target pressures is too slow, which is easy to cause user complaints. Therefore, the fixed slope pressure building strategy has certain limitations. It is necessary to introduce a variable slope pressure relief strategy to solve this type of pressure building problem.

[0028] At present, mainstream IBCU manufacturers limit the static target pressure building conditions of the vehicle to a constant pressure building slope (such as 150bar / s), and the target pressure is usually limited to 78bar, such as IPB (Integrated PowerBrake); the maximum pressure is also limited due to different slopes, gears and other different working conditions, such as Continental's wire-controlled brake system MKC-2, which limits the maximum pressure to 10bar when the vehicle is on flat ground and in P gear. The purpose is to improve the vehicle pressure overshoot and the resulting NVH problem.

[0029] In order to solve the above problems, a vehicle braking control method, system, device and medium according to an embodiment of the present application are described below in conjunction with the accompanying drawings.

[0030] An embodiment of the present application provides a vehicle braking control method, which is applied to a terminal device. In the present application scheme, the terminal device or server is used as the execution subject to illustrate the present application scheme. The terminal device or server is used to execute the steps of a vehicle braking control method.

[0031] See also Figure 3 , Figure 3 A vehicle braking control method is shown as an exemplary embodiment of the present application, such as Figure 3 As shown, the present application provides a vehicle braking control method, comprising:

[0032] Step S31, obtaining the driving state of the vehicle and the state parameters corresponding to the driving state;

[0033] Step S32, obtaining a comfortable pressure building requirement parameter of the vehicle based on the driving state and the state parameter;

[0034] Step S33, obtaining an initial target electric cylinder brake pressure of the vehicle, and obtaining a target electric cylinder brake pressure of the vehicle based on the initial target electric cylinder brake pressure and a comfortable pressure building requirement parameter;

[0035] Step S34, controlling the electric cylinder of the vehicle to brake based on the target electric cylinder brake pressure.

[0036] A vehicle braking control method of this embodiment first obtains the driving state and corresponding state parameters of the vehicle, and obtains the comfortable pressure buildup requirement parameters of the vehicle based on the driving state and state parameters. Then, the initial target electric cylinder braking pressure of the vehicle is obtained, and the target electric cylinder braking pressure of the vehicle is obtained based on the initial target electric cylinder braking pressure and the comfortable pressure buildup requirement parameters, and the electric cylinder of the vehicle is controlled to brake based on the target electric cylinder braking pressure. In this way, when the vehicle brakes, the driving state and state parameters of the vehicle are taken into consideration to obtain the target braking pressure that meets the driver's comfortable pressure buildup requirement for the vehicle to brake the vehicle, which can meet the driver's current braking needs and thus improve the driver's driving experience. Among them, the comfortable pressure buildup requirement parameter represents a weight parameter that meets the driver's current comfortable braking needs for the vehicle.

[0037] Optionally, the state parameters include driving parameters, and the driving parameters include current vehicle speed, current slope, current brake push rod stroke, and current brake push rod stroke rate;

[0038] The vehicle's comfortable pressure building requirement parameters are obtained based on the driving state and state parameters, including:

[0039] When the driving state is a non-stationary state, the pressure building sub-parameters are obtained based on the driving parameter table lookup, and the pressure building sub-parameters include vehicle speed pressure building parameters, slope pressure building parameters, brake push rod stroke pressure building parameters and brake push rod stroke rate pressure building parameters;

[0040] The comfortable pressure building requirement parameters of the vehicle are calculated based on the pressure building sub-parameters;

[0041] The calculation formula of the comfortable pressure building requirement parameter is as follows:

[0042] a=a1*a2*a3*a4;

[0043] Among them, a represents the comfort pressure building requirement parameter, a1 represents the vehicle speed pressure building parameter, a2 represents the slope pressure building parameter, a3 represents the brake push rod stroke pressure building parameter, and a4 represents the brake push rod stroke rate pressure building parameter.

[0044] In the embodiment provided by the present application, when the driving state of the vehicle is not stationary, the vehicle's comfortable pressure building requirement parameters are calculated based on the pressure building sub-parameters obtained by looking up the driving parameter table, which can determine whether the driver currently has a comfortable pressure building braking demand, so that the vehicle's target electric cylinder braking pressure can be obtained based on the driver's current braking demand to perform vehicle braking, thereby improving the driver's driving experience.

[0045] In the embodiment provided by the present application, the vehicle speed pressure building parameter, the slope pressure building parameter, the brake push rod stroke pressure building parameter and the brake push rod stroke rate pressure building parameter are all numerical values ​​obtained by test calibration, and their value ranges are all 0 to 1, so the value range of the comfortable pressure building demand parameter is also 0 to 1. When the current vehicle speed is greater than the vehicle speed threshold, and / or the current slope of the driving road is greater than the slope threshold, and / or the current brake push rod stroke is greater than the safety threshold, and / or the current brake push rod stroke rate is greater than the rate threshold, it means that the driver does not have a comfortable pressure building braking demand, and is more inclined to safe braking at this time, then the corresponding pressure building sub-parameter is 0, so the corresponding comfortable pressure building demand parameter is 0. Only when the current vehicle speed is less than or equal to the vehicle speed threshold, and the current driving road slope is less than or equal to the slope threshold, and the current brake push rod stroke is less than or equal to the safety threshold, and the current brake push rod stroke rate is less than or equal to the rate threshold, it means that the driver has a comfortable pressure building braking demand, and the comfortable pressure building demand parameter is obtained by multiplying each pressure building sub-parameter.

[0046] In the embodiment provided by the present application, the table data used to obtain the pressure building sub-parameters through table lookup are shown in Tables 1 to 4 below, wherein the correspondence between the calibrated current vehicle speed and the vehicle speed pressure building parameter a1 is shown in Table 1.

[0047] Table 1

[0048] Current vehicle speed (m / s) 10 12 14 16 18 20 <![CDATA[a1]]> 1 0.8 0.6 0.4 0.2 0

[0049] The corresponding relationship between the calibrated current slope and the slope pressure building parameter a2 is shown in Table 2.

[0050] Table 2

[0051] <![CDATA[Current slope (m / s 2 )]]> 0.8 1 1.3 1.6 1.9 2.0 <![CDATA[a2]]> 1 0.8 0.6 0.4 0.1 0

[0052] The corresponding relationship between the calibrated current brake push rod stroke and the brake push rod stroke pressure building parameter a3 is shown in Table 2.

[0053] Table 3

[0054]

[0055] The corresponding relationship between the calibrated current brake push rod stroke rate and the brake push rod stroke rate pressure building parameter a4 is shown in Table 2.

[0056] Table 4

[0057]

[0058] The above are the initial values ​​of a1, a2, a3, and a4. Calibration engineers will need to make precise adjustments based on customer needs to achieve personalized braking customization.

[0059] Optionally, obtaining a target electric cylinder brake pressure of the vehicle based on the initial target electric cylinder brake pressure and a comfortable pressure build-up requirement parameter includes:

[0060] When the comfortable pressure building demand parameter is greater than 0, the expected electric cylinder pressure overshoot value is obtained by looking up the table based on the comfortable pressure building demand parameter;

[0061] The wheel cylinder brake fluid increment of the vehicle is obtained by looking up a table based on the expected electric cylinder pressure overshoot value;

[0062] Calculating a target electric cylinder brake pressure of the vehicle based on an expected electric cylinder pressure overshoot value, a wheel cylinder brake fluid increment, and an initial target electric cylinder brake pressure;

[0063] When the comfort pressure buildup requirement parameter is 0, the initial target electric cylinder brake pressure is used as the target electric cylinder brake pressure of the vehicle.

[0064] In the embodiment provided by the present application, when the comfortable pressure building requirement parameter is greater than 0, it indicates that the driver has a braking requirement for comfortable pressure building. At this time, the expected electric cylinder pressure overshoot value is obtained by looking up the table based on the comfortable pressure building requirement parameter, and the target electric cylinder brake pressure that meets the driver's braking requirement for comfortable pressure building is calculated based on the expected electric cylinder pressure overshoot value, the wheel cylinder brake fluid increment and the initial target electric cylinder brake pressure, so as to improve the driving experience of the subsequent driver when the vehicle is braked based on the target electric cylinder brake pressure. At the same time, when calculating the target electric cylinder brake pressure, the pressure overshoot of the electric cylinder can be taken into account, and the vibration, noise and acoustic roughness caused by the collision of the brake fluid and the valve caused by the overshoot of the electric cylinder pressure can be reduced, so as to reduce the user's NVH complaints about the vehicle. When the comfortable pressure building requirement parameter is 0, it indicates that the driver currently prefers safe braking, and the braking requirement is safe pressure building. At this time, the initial target electric cylinder brake pressure is directly used as the target electric cylinder brake pressure of the vehicle for vehicle braking, which can not only meet the driver's braking demand, but also improve the safety of braking.

[0065] In the embodiment provided by the present application, the table data used to obtain the wheel cylinder brake fluid increment of the vehicle is shown in Table 5, that is, the corresponding relationship between the comfort pressure buildup demand parameter a with a value range of 0 to 1 and the expected electric cylinder pressure overshoot value Δp is shown in Table 5.

[0066] Table 5

[0067] a 0.01 0.3 0.5 0.8 0.9 1 Δp(bar) 45 10 5 3 2 1

[0068] When the comfort pressure buildup requirement parameter a is 0, the driver's pressure buildup request should be regarded as a safety pressure buildup request, and its target pressure buildup slope is not restricted. At this time, the driver's braking demand can be met by directly braking the vehicle according to the initial target electric cylinder brake pressure.

[0069] Optionally, the target electric cylinder brake pressure of the vehicle is calculated based on the expected electric cylinder pressure overshoot value, the wheel cylinder brake fluid increment and the initial target electric cylinder brake pressure, including:

[0070] The brake fluid flow rate of the vehicle's fluid inlet valve is calculated based on the expected electric cylinder pressure overshoot value;

[0071] The calculation formula of brake fluid flow is as follows:

[0072]

[0073] Wherein, Q represents the brake fluid flow through the inlet valve under the expected electric cylinder pressure overshoot value Δp, C represents the Bernoulli constant, C = 4.4;

[0074] The reference pressure build-up slope is calculated based on the expected electric cylinder pressure overshoot value, wheel cylinder brake fluid increment and brake fluid flow rate;

[0075] The calculation formula of the reference pressure build-up slope is as follows:

[0076] P RefGrandient =ΔP / (ΔV / q Ref );

[0077] Among them, P RefGrandient represents the reference pressure slope, ΔP represents the expected electric cylinder pressure overshoot value, ΔV represents the wheel cylinder brake fluid increment, q Ref Indicates brake fluid flow;

[0078] Based on the reference pressure building slope and the expected electric cylinder pressure overshoot value, the target pressure building slope is calculated;

[0079] The calculation formula of the target pressure building slope is as follows:

[0080]

[0081] Among them, P Grandient Indicates the target pressure build-up slope, P RefGrandient It represents the reference pressure building slope, and Δp represents the expected electric cylinder pressure overshoot value;

[0082] The target electric cylinder brake pressure of the vehicle is calculated based on the target pressure build-up slope and the initial target electric cylinder brake pressure.

[0083] In the embodiment provided by the present application, the brake fluid flow of the vehicle's inlet valve is obtained based on the expected electric cylinder pressure overshoot value, and the reference pressure building slope is calculated based on the expected electric cylinder pressure overshoot value, the wheel cylinder brake fluid increment and the brake fluid flow, and then the target pressure building slope is calculated based on the reference pressure building slope and the expected electric cylinder pressure overshoot value, and the target electric cylinder brake pressure of the vehicle is calculated based on the target pressure building slope and the initial target electric cylinder brake pressure. In this way, the vehicle is braked based on the target electric cylinder brake pressure obtained by the target pressure building slope, and the pressure building slope of the electric cylinder can be limited. The vibration, noise and acoustic roughness caused by the collision of the brake fluid and the valve caused by the electric cylinder pressure overshoot can not only reduce the user's NVH complaints about the vehicle, but also improve the driving experience of subsequent drivers when braking the vehicle based on the target electric cylinder brake pressure.

[0084] In the embodiment provided by the present application, taking the inlet valve as the Yilong inlet valve as an example, it is measured through experiments that in the IBCU wire control system, the driver can build pressure by stepping on the brake pedal. When the pressure is built at the fastest motor speed, a pressure difference of about 45 bar can be generated at both ends of the Yilong inlet valve (the pressure difference is the expected electric cylinder pressure overshoot value). Therefore, when the driver's comfort pressure buildup requirement parameter a is very close to 0, the expected electric cylinder pressure overshoot value Δp reaches the theoretical maximum value of 45 bar. Only when the driver's comfort pressure buildup requirement parameter a is relatively large, a smaller expected electric cylinder pressure overshoot value Δp will be given to limit the target pressure buildup slope.

[0085] The experimentally measured brake fluid flow of the Yilong inlet valve (front wheel) under different pressure differences is shown in Table 6.

[0086] Table 6

[0087]

[0088]

[0089] Bernoulli constant C = 4.4. When the pressure difference between the two ends of the Yilong inlet valve is 1 bar (taking 1 bar as the reference pressure difference, assuming that the Bernoulli constant at this time has no attenuation, and the pressure of the electric cylinder is consistent with the pressure at the front end of the inlet valve), the reference flow rate q of the Yilong inlet valve Ref About 4.4ml / s.

[0090] The P_V relationship of the front wheel cylinder is the same as the corresponding relationship between the expected electric cylinder pressure overshoot value and the wheel cylinder brake fluid increment. The P_V relationship of the front wheel cylinder of a certain project test vehicle measured experimentally is shown in Table 7.

[0091] Table 7

[0092] Wheel cylinder pressure P (bar) Brake fluid volume V(ml) 2 0.277760119 5 0.581733272 10 0.884444287 15 1.127494785 25 1.575731599 35 1.935031349 50 2.377551816 70 2.856506759 100 3.429980672 130 3.892498524 160 4.279667581 200 4.711667444

[0093] The reference flow rate q of the Yilong inlet valveRef =4.4ml / s, the pressure increment ΔP of the wheel cylinder pressure from 0bar to 2bar is the same as the expected electric cylinder pressure overshoot value, which is 2bar. Then, a fluid volume of ΔV of 0.278ml (this fluid volume is the wheel cylinder brake fluid increment) needs to be discharged into the wheel cylinder, and the required time ΔT is 0.0632s. The reference pressure slope P from 0bar to 2bar is calculated according to the formula RefGrandient The base pressure slope P from 2 bar to 5 bar is 32 bar / s. RefGrandient The electric cylinder target brake pressure and the reference pressure slope P RefGrandient The corresponding relationship is shown in Table 8 (the expected electric cylinder pressure overshoot value is 1 bar).

[0094] Table 8

[0095]

[0096] Optionally, the state parameters include control parameters, and the control parameters include the current driving gear and the current brake push rod stroke;

[0097] The vehicle's comfortable pressure building requirement parameters are obtained based on the driving state and state parameters, including:

[0098] When the driving state is stationary and the control parameters meet the preset requirements, the comfortable pressure building demand parameter of the vehicle is determined to be 1;

[0099] When the driving state is a stationary state and the control parameters do not meet the preset requirements, the comfort pressure building demand parameter of the vehicle is determined to be 0.

[0100] In the embodiment provided by the present application, when the driving state is a stationary state, the control parameters of the vehicle can reflect the driver's braking demand. When the control parameters meet the preset requirements, it means that the driver has a braking demand for comfortable pressure building. At this time, the vehicle's comfortable pressure building demand parameter is determined to be the maximum value 1, so that the braking process of the vehicle in the stationary state can always meet the driver's comfortable pressure building demand to the greatest extent. When the control parameters do not meet the preset requirements, it means that the driver's braking demand is for safe pressure building, and the comfort of pressure building does not need to be considered. At this time, the vehicle's comfortable pressure building demand parameter is determined to be the minimum value 0, so that the braking process of the vehicle in the stationary state can always meet the driver's safe pressure building demand to the greatest extent. Among them, the preset requirements are that the current driving gear is a non-driving gear of P gear or N gear, and the current brake push rod stroke is less than or equal to the safety threshold.

[0101] Optionally, obtaining a target electric cylinder brake pressure of the vehicle based on the initial electric cylinder target brake pressure and a comfortable pressure build-up requirement parameter includes:

[0102] When the comfortable pressure buildup requirement parameter is 1, the vehicle's limited target electric cylinder brake pressure is calculated based on the initial target electric cylinder brake pressure and the initial pressure buildup slope;

[0103] Obtain the current slope of the vehicle, and obtain the target upper limit value of the electric cylinder brake pressure of the vehicle by looking up the table based on the current slope;

[0104] Based on the limited target electric cylinder brake pressure and the target electric cylinder brake pressure upper limit value, a target electric cylinder brake pressure of the vehicle is obtained;

[0105] When the comfort pressure buildup requirement parameter is 0, the initial target electric cylinder brake pressure is used as the target electric cylinder brake pressure of the vehicle.

[0106] In the embodiment provided by the present application, when the comfort pressure buildup demand parameter is 1, it indicates that the driver has a braking demand for maximum comfort pressure buildup. At this time, based on the electric cylinder target braking pressure (0 bar) of the first calculation cycle (the current calculation cycle is set to 5ms), the table is looked up to obtain the product of the benchmark pressure buildup slope (32 bar / s) and 5ms, and the electric cylinder target braking force of the first calculation cycle is obtained by taking the smaller of the initial electric cylinder target braking pressure. The electric cylinder target braking force calculated in the first calculation cycle is used as the electric cylinder target braking force of the second calculation cycle to look up the table to obtain the benchmark pressure buildup slope of the second calculation cycle, and the product of the benchmark pressure buildup slope of the second calculation cycle and 5ms is taken the smaller of the initial electric cylinder target braking pressure to obtain the electric cylinder target braking force of the second calculation cycle, and so on. The target electric cylinder brake pressure after vehicle restriction in each calculation cycle is obtained, and when the vehicle is stationary and the gear signal is P or N gear and the driver's push rod stroke is not greater than the safety threshold, the upper limit value of the target electric cylinder brake pressure of the vehicle is obtained by looking up the table based on the current slope and the target electric cylinder brake pressure of each calculation cycle is taken as the smaller one to obtain the target electric cylinder brake pressure, so as to improve the driving experience of subsequent drivers when braking the vehicle based on the target electric cylinder brake pressure. When the comfortable pressure building demand parameter is 0, it means that the driver currently tends to brake safely and the braking demand is a safe pressure building demand. At this time, the initial target electric cylinder brake pressure is used as the target electric cylinder brake pressure of the vehicle for vehicle braking, which can not only meet the driver's braking demand, but also improve the safety of braking.

[0107] In the embodiment provided by the present application, if the vehicle is stationary and the current driving gear is in the non-driving gear of P gear or N gear, at this time, as long as the current brake push rod stroke of the driver stepping on the pedal does not exceed the safety threshold, it is considered that the driver has a comfortable pressure build-up demand, and a relatively slow pressure build-up slope will be used to limit it. At the same time, according to the current slope size, the table is consulted to set the upper limit value of the target electric cylinder brake pressure.

[0108] Among them, the table data used to look up the table to obtain the upper limit value of the target electric cylinder brake pressure of the vehicle is shown in Table 9, that is, the corresponding relationship between the current slope and the upper limit value of the target electric cylinder brake pressure is shown in Table 9.

[0109] Table 9

[0110] <![CDATA[Current slope (m / s 2 )]]> 0.5 1.0 1.5 2.0 2.5 3 Target pressure upper limit (bar) 10 20 30 40 50 60

[0111] Optionally, based on the limited target electric cylinder brake pressure and the target electric cylinder brake pressure upper limit value, the target electric cylinder brake pressure of the vehicle is obtained, including:

[0112] When the limited target electric cylinder brake pressure is less than or equal to the target electric cylinder brake pressure upper limit value, the limited target electric cylinder brake pressure is used as the target electric cylinder brake pressure of the vehicle;

[0113] When the target electric cylinder brake pressure is limited to be greater than the target electric cylinder brake pressure upper limit value, the target electric cylinder brake pressure upper limit value is used as the target electric cylinder brake pressure of the vehicle.

[0114] In the embodiment provided by the present application, when the target electric cylinder brake pressure is limited to be less than or equal to the target electric cylinder brake pressure upper limit value, the limited target electric cylinder brake pressure is used as the target electric cylinder brake pressure of the vehicle, and when the target electric cylinder brake pressure is limited to be greater than the target electric cylinder brake pressure upper limit value, the target electric cylinder brake pressure upper limit value is used as the target electric cylinder brake pressure of the vehicle. This enables the target brake pressure of the vehicle to always be less than the target electric cylinder brake pressure upper limit value, thereby ensuring the driver's comfortable pressure building needs while also improving the safety of the vehicle's braking process.

[0115] See also Figure 4 , Figure 4 In an exemplary embodiment of the present application, a flow chart of a vehicle braking control method provided by the application is shown as follows: Figure 4 As shown, the comfortable pressure building demand factor calculation module uses the acquired driving state and state parameters (including the current vehicle speed corresponding to the vehicle speed signal, the current brake push rod stroke and the current brake push rod stroke rate corresponding to the brake push rod signal) to calculate the driver's comfortable braking demand factor (i.e., the comfortable pressure building demand parameter). Then, the target pressure limiting module uses the comfortable braking demand factor (i.e., the comfortable pressure building demand parameter), the driving state corresponding to the vehicle stationary signal, the current driving gear corresponding to the gear signal, the current slope corresponding to the slope signal, the current brake push rod stroke and the current brake push rod stroke rate corresponding to the brake push rod signal, and the initial target pressure (initial target electric cylinder brake pressure) to calculate the final target pressure (i.e., the target electric cylinder brake pressure). In addition, Figure 4 Z -1 Indicates that the signal is delayed by one cycle.

[0116] See also Figure 5, Figure 5 FIG. 1 is a schematic diagram of a hydraulic circuit of a brake-by-wire system for a vehicle brake control method in an exemplary embodiment of the present application. Figure 5 The names and descriptions of the components are shown in Table 10.

[0117] Table 10

[0118]

[0119] The inlet valve is located between the wheel cylinder and the electric cylinder. Figure 5 As shown, the connection relationship of each component in the hydraulic circuit of the wire control brake system is displayed. When the IBCU functions normally, the driver steps on the brake pedal, the brake master cylinder push rod squeezes the master cylinder, and the brake fluid in the master cylinder is squeezed and flows to the simulator cavity through the SSV valve. A feedback force similar to the vacuum master cylinder is generated in the simulator cavity and given to the push rod. The brake push rod transmits the feedback force to the driver. At this time, the two valves CSV1 / 2 are powered on and closed, and the PSV1 / 2 are powered on and opened, and the electric cylinder hydraulic circuit and the master cylinder hydraulic circuit are isolated. The target brake pressure of the electric cylinder is obtained by looking up the position of the master cylinder push rod through a table. With the target brake pressure of the cylinder, the electric cylinder motor can be controlled to rotate, driving the plunger to discharge fluid into the wheel cylinder, the brake fluid in the wheel cylinder increases, the wheel cylinder expands, squeezes the brake friction pad, generates clamping force, and brakes the vehicle, which is in the wire control brake working state.

[0120] When the IBCU function is downgraded, the driver presses the pedal at this time, and all valves are de-energized. SSV valve is normally closed, CSV1 / 2 valve is normally open, PSV1 / 2 is normally closed, IVFL / FR / RL / RR is normally open, and OVFL / FR / RL / RR is normally closed. The master cylinder and wheel cylinder are directly connected. When the driver presses the brake pedal, the master cylinder is squeezed to discharge fluid into the wheel cylinder. The brake fluid in the wheel cylinder increases, the wheel cylinder expands, and the brake friction pad is squeezed to generate clamping force, thereby braking the vehicle and being in a backup braking state.

[0121] The vehicle braking control method of the present application, in order to eliminate obvious electric cylinder pressure overshoot while relaxing the pressure building slope restriction as much as possible to achieve a fast and comfortable pressure building effect, makes appropriate restrictions on the boost slope and target pressure upper limit of comfortable braking based on the above-mentioned variable pressure slope restriction theory by judging the driver's comfortable braking needs, instead of limiting them with a constant value, ensuring that when the driver has a comfortable boost demand, the boost slope is not low and will not cause an unacceptable overshoot of the electric cylinder, thereby optimizing the NVH problem caused by the overshoot of the electric cylinder. Since the driver's comfortable braking needs are judged and appropriate target pressure restrictions are made, the system has better robustness in most daily driver use.

[0122] An alternative to this application may be to improve the hardware of the inlet valve, such as changing the inlet valve diameter to be large enough so that when passing through the inlet valve, even if the flow rate is large, a large pressure difference will not be formed at both ends of the valve, thereby reducing the flow rate of the brake fluid through the inlet valve and improving NVH. It can also be to optimize the motor casting process so that when the motor works at a higher speed, the noise of the wire control brake system is relatively small.

[0123] See also Figure 6 , Figure 6 A vehicle braking control system is shown as an exemplary embodiment of the present application, such as Figure 6 As shown, the present application provides a vehicle braking control system 600, comprising:

[0124] The acquisition module 601 is used to acquire the driving state of the vehicle and the state parameters corresponding to the driving state;

[0125] A first obtaining module 602 is used to obtain a comfortable pressure building requirement parameter of the vehicle based on the driving state and the state parameter;

[0126] The second obtaining module 603 is used to obtain the initial target electric cylinder brake pressure of the vehicle, and obtain the target electric cylinder brake pressure of the vehicle based on the initial target electric cylinder brake pressure and the comfortable pressure building requirement parameter;

[0127] The braking module 604 is used to control the electric cylinder of the vehicle to brake based on the target electric cylinder braking pressure.

[0128] In a vehicle braking control system of this embodiment, first, the driving state and corresponding state parameters of the vehicle are obtained by an acquisition module 601, and the comfortable pressure building requirement parameters of the vehicle are obtained by a first acquisition module 602 based on the driving state and the state parameters. Then, the initial target electric cylinder braking pressure of the vehicle is obtained by a second acquisition module 603, and the target electric cylinder braking pressure of the vehicle is obtained based on the initial target electric cylinder braking pressure and the comfortable pressure building requirement parameters, and the electric cylinder of the vehicle is controlled to brake based on the target electric cylinder braking pressure by a braking module 604. In this way, when the vehicle brakes, the driving state and state parameters of the vehicle are taken into consideration to obtain the target braking pressure that meets the driver's comfortable pressure building requirement for the vehicle to brake the vehicle, which can meet the driver's current braking requirements, thereby improving the driver's driving experience.

[0129] Optionally, the state parameters include driving parameters, and the driving parameters include current vehicle speed, current slope, current brake push rod stroke, and current brake push rod stroke rate;

[0130] First, get the module, specifically for:

[0131] When the driving state is a non-stationary state, the pressure building sub-parameters are obtained by looking up the table based on the driving parameters;

[0132] The comfortable pressure building requirement parameters of the vehicle are calculated based on the pressure building sub-parameters.

[0133] Optionally, the second obtaining module is specifically used for:

[0134] When the comfortable pressure building demand parameter is greater than 0, the expected electric cylinder pressure overshoot value is obtained by looking up the table based on the comfortable pressure building demand parameter;

[0135] The wheel cylinder brake fluid increment of the vehicle is obtained by looking up a table based on the expected electric cylinder pressure overshoot value;

[0136] Calculating a target electric cylinder brake pressure of the vehicle based on an expected electric cylinder pressure overshoot value, a wheel cylinder brake fluid increment, and an initial target electric cylinder brake pressure;

[0137] When the comfort pressure buildup requirement parameter is 0, the initial target electric cylinder brake pressure is used as the target electric cylinder brake pressure of the vehicle.

[0138] Optionally, the second obtaining module is specifically used for:

[0139] The brake fluid flow rate of the vehicle's fluid inlet valve is calculated based on the expected electric cylinder pressure overshoot value;

[0140] The reference pressure build-up slope is calculated based on the expected electric cylinder pressure overshoot value, wheel cylinder brake fluid increment and brake fluid flow rate;

[0141] Based on the reference pressure building slope and the expected electric cylinder pressure overshoot value, the target pressure building slope is calculated;

[0142] The target electric cylinder brake pressure of the vehicle is calculated based on the target pressure build-up slope and the initial target electric cylinder brake pressure.

[0143] Optionally, the state parameters include control parameters, and the control parameters include the current driving gear and the current brake push rod stroke;

[0144] First, get the module, specifically for:

[0145] The vehicle's comfortable pressure building requirement parameters are obtained based on the driving state and state parameters, including:

[0146] When the driving state is stationary and the control parameters meet the preset requirements, the comfortable pressure building demand parameter of the vehicle is determined to be 1;

[0147] When the driving state is a stationary state and the control parameters do not meet the preset requirements, the comfort pressure building demand parameter of the vehicle is determined to be 0.

[0148] Optionally, the second obtaining module is specifically used for:

[0149] When the comfortable pressure buildup requirement parameter is 1, the vehicle's limited target electric cylinder brake pressure is calculated based on the initial target electric cylinder brake pressure and the initial pressure buildup slope;

[0150] Obtain the current slope of the vehicle, and obtain the target upper limit value of the electric cylinder brake pressure of the vehicle by looking up the table based on the current slope;

[0151] Based on the limited target electric cylinder brake pressure and the target electric cylinder brake pressure upper limit value, a target electric cylinder brake pressure of the vehicle is obtained;

[0152] When the comfort pressure buildup requirement parameter is 0, the initial target electric cylinder brake pressure is used as the target electric cylinder brake pressure of the vehicle.

[0153] Optionally, the second obtaining module is specifically used for:

[0154] When the limited target electric cylinder brake pressure is less than or equal to the target electric cylinder brake pressure upper limit value, the limited target electric cylinder brake pressure is used as the target electric cylinder brake pressure of the vehicle;

[0155] When the target electric cylinder brake pressure is limited to be greater than the target electric cylinder brake pressure upper limit value, the target electric cylinder brake pressure upper limit value is used as the target electric cylinder brake pressure of the vehicle.

[0156] It should be noted that the vehicle braking control system provided in the above embodiment and the vehicle braking control method provided in the above embodiment belong to the same concept, wherein the specific manner in which each module and unit performs operations has been described in detail in the method embodiment and will not be repeated here. In practical applications, the vehicle braking control system provided in the above embodiment can allocate the above functions to different functional modules as needed, that is, divide the internal structure of the system into different functional modules to complete all or part of the functions described above, and this is not limited here.

[0157] A computing device according to an embodiment of the present application includes a memory, a processor, and a program stored in the memory and running on the processor. When the processor executes the program, some or all steps of the above-mentioned vehicle braking control method are implemented.

[0158] Among them, the computing device can be a computer, and correspondingly, its program is computer software. The above-mentioned parameters and steps in a computing device of the present application can refer to the parameters and steps in an embodiment of a vehicle braking control method above, and will not be repeated here.

[0159] In an embodiment of the present application, a computer-readable storage medium is provided, in which instructions are stored. When the instructions are executed, the steps of the above-mentioned vehicle braking control method are executed.

[0160] The computer-readable storage medium may be a transient computer-readable storage medium or a non-transitory computer-readable storage medium.

[0161] The technical solution of the embodiment of the present disclosure can be embodied in the form of a software product, which is stored in a storage medium and includes one or more instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method of the embodiment of the present disclosure. The aforementioned computer-readable storage medium may be a non-transitory computer-readable storage medium, including: a USB flash drive, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a disk or an optical disk, and other media that can store program codes, or a transient computer-readable storage medium.

[0162] The flowchart and block diagram in the accompanying drawings illustrate the possible architecture, functions and operations of the system, method and computer program product according to various embodiments of the present application. Wherein, each box in the flowchart or block diagram can represent a module, a program segment, or a part of the code, and the above-mentioned module, program segment, or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0163] Those skilled in the art know that the present application can be implemented as a system, method or computer program product. Therefore, the present disclosure can be specifically implemented in the following forms, namely: it can be complete hardware, it can be complete software (including firmware, resident software, microcode, etc.), or it can be a combination of hardware and software, generally referred to as "circuit", "module" or "system" herein. In addition, in some embodiments, the present application can also be implemented in the form of a computer program product in one or more computer-readable media, and the computer-readable medium contains computer-readable program code. Computer-readable storage media can be, for example, but not limited to - electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or devices, or any combination of the above.

[0164] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0165] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A vehicle braking control method, characterized in that: include: Acquiring a driving state of a vehicle and a state parameter corresponding to the driving state; Obtaining a comfortable pressure building requirement parameter of the vehicle based on the driving state and the state parameter; Acquiring an initial target electric cylinder brake pressure of the vehicle, and obtaining a target electric cylinder brake pressure of the vehicle based on the initial target electric cylinder brake pressure and the comfortable pressure building requirement parameter; The electric cylinder of the vehicle is controlled to brake based on the target electric cylinder brake pressure.

2. The method according to claim 1, characterized in that The state parameters include driving parameters, and the driving parameters include current vehicle speed, current slope, current brake push rod stroke, and current brake push rod stroke rate; The obtaining of the comfortable pressure building requirement parameter of the vehicle based on the driving state and the state parameter includes: When the driving state is a non-stationary state, a pressure building sub-parameter is obtained by looking up a table based on the driving parameter; A comfortable pressure building requirement parameter of the vehicle is calculated based on the pressure building sub-parameter.

3. The method according to claim 2, characterized in that The step of obtaining the target electric cylinder brake pressure of the vehicle based on the initial target electric cylinder brake pressure and the comfortable pressure building requirement parameter includes: When the comfortable pressure buildup requirement parameter is greater than 0, an expected electric cylinder pressure overshoot value is obtained by looking up a table based on the comfortable pressure buildup requirement parameter; Obtaining a wheel cylinder brake fluid increment of the vehicle by looking up a table based on the expected electric cylinder pressure overshoot value; Calculating a target electric cylinder brake pressure of the vehicle based on the expected electric cylinder pressure overshoot value, the wheel cylinder brake fluid increment and the initial target electric cylinder brake pressure; When the comfort pressure buildup requirement parameter is equal to 0, the initial target electric cylinder brake pressure is used as the target electric cylinder brake pressure of the vehicle.

4. The method according to claim 3, characterized in that The step of calculating the target electric cylinder brake pressure of the vehicle based on the expected electric cylinder pressure overshoot value, the wheel cylinder brake fluid increment and the initial target electric cylinder brake pressure comprises: Calculating a brake fluid flow rate of a fluid inlet valve of the vehicle based on the expected electric cylinder pressure overshoot value; Calculating a reference pressure build-up slope based on the expected electric cylinder pressure overshoot value, the wheel cylinder brake fluid increment, and the brake fluid flow rate; Calculating a target pressure building slope based on the reference pressure building slope and the expected electric cylinder pressure overshoot value; The target electric cylinder brake pressure of the vehicle is calculated based on the target pressure building slope and the initial target electric cylinder brake pressure.

5. The method according to any one of claims 1 to 4, characterized in that: The state parameters include control parameters, and the control parameters include the current driving gear and the current brake push rod stroke; The obtaining of the comfortable pressure building requirement parameter of the vehicle based on the driving state and the state parameter includes: When the driving state is a stationary state and the control parameter meets the preset requirement, determining that the comfortable pressure building demand parameter of the vehicle is 1; When the driving state is a stationary state and the control parameter does not meet the preset requirement, it is determined that the comfort pressure building demand parameter of the vehicle is 0.

6. The method according to claim 5, characterized in that The step of obtaining the target electric cylinder brake pressure of the vehicle based on the initial target electric cylinder brake pressure and the comfortable pressure building requirement parameter includes: When the comfortable pressure buildup requirement parameter is 1, based on the initial target electric cylinder brake pressure and the initial pressure buildup slope, a limited target electric cylinder brake pressure of the vehicle is calculated; Acquiring the current slope of the vehicle, and obtaining a target electric cylinder brake pressure upper limit value of the vehicle by looking up a table based on the current slope; Based on the limited target electric cylinder brake pressure and the target electric cylinder brake pressure upper limit value, obtaining the target electric cylinder brake pressure of the vehicle; When the comfort pressure buildup requirement parameter is 0, the initial target electric cylinder brake pressure is used as the target electric cylinder brake pressure of the vehicle.

7. The method according to claim 6, characterized in that The step of obtaining the target electric cylinder brake pressure of the vehicle based on the limited target electric cylinder brake pressure and the target electric cylinder brake pressure upper limit value comprises: When the limited target electric cylinder brake pressure is less than or equal to the target electric cylinder brake pressure upper limit value, using the limited target electric cylinder brake pressure as the target electric cylinder brake pressure of the vehicle; When the limited target electric cylinder brake pressure is greater than the target electric cylinder brake pressure upper limit value, the target electric cylinder brake pressure upper limit value is used as the target electric cylinder brake pressure of the vehicle.

8. A vehicle braking control system, characterized in that: include: An acquisition module, used to acquire the driving state of the vehicle and state parameters corresponding to the driving state; A first obtaining module, configured to obtain a comfortable pressure building requirement parameter of the vehicle based on the driving state and the state parameter; a second obtaining module, configured to obtain an initial target electric cylinder braking pressure of the vehicle, and obtain a target electric cylinder braking pressure of the vehicle based on the initial target electric cylinder braking pressure and the comfortable pressure building requirement parameter; A brake module is used to control the electric cylinder of the vehicle to brake based on the target electric cylinder brake pressure.

9. A computing device comprising a memory, a processor, and a program stored in the memory and running on the processor, characterized in that: When the processor executes the program, the steps of a vehicle braking control method as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores instructions, and when the instructions are executed on a terminal device, the terminal device executes the steps of a vehicle braking control method as described in any one of claims 1 to 7.

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