Wheel cylinder pressure determination method

Abstract

The present application relates to a method for determining wheel cylinder pressure. Based on the oil flow rate passing through each boost valve in the controller at the current moment, the volume of oil flowing into the wheel cylinder corresponding to each boost valve at the current moment is obtained. Based on the oil flow rate passing through the pressure reducing valve corresponding to each boost valve in the controller at the current moment, the volume of oil flowing out of each wheel cylinder at the current moment is obtained. Based on the current inflow and outflow volumes of each wheel cylinder and the oil volume of each wheel cylinder at the previous moment, the oil volume of each wheel cylinder at the next moment is determined. Then, based on a preset volume-pressure change relationship and the oil volume of each wheel cylinder at the next moment, the wheel cylinder pressure of each wheel cylinder at the next moment is determined. This method enables the determination of the wheel cylinder pressure of a wheel cylinder without the need for a wheel cylinder pressure sensor, saving costs.

Description

Technical Field

[0001] The present application relates to the field of vehicle control technology, and in particular to a method for determining wheel cylinder pressure. Background Art

[0002] With the development of electric and smart cars, the braking systems of these vehicles have put forward requirements such as electronic power steering and active supercharging. Braking systems are constantly evolving towards brake-by-wire systems, and brake pressure is a prerequisite for achieving vehicle control.

[0003] Taking the electronic hydraulic brake system within a brake-by-wire system as an example, wheel cylinder pressure is the most critical state variable in this system. In existing technology, wheel cylinder pressure is acquired using wheel cylinder pressure sensors. However, installing wheel cylinder pressure sensors is expensive, resulting in a high cost for acquiring wheel cylinder pressure. Summary of the Invention

[0004] Based on this, it is necessary to provide a method for determining wheel cylinder pressure to address the above technical issues, which can reduce the cost of obtaining wheel cylinder pressure.

[0005] In a first aspect, the present application provides a method for determining wheel cylinder pressure, the method comprising:

[0006] The oil volume flowing into the wheel cylinder corresponding to each boosting valve at the current moment is obtained based on the oil flow rate passing through each boosting valve in the controller at the current moment; and the oil volume flowing out of each wheel cylinder at the current moment is obtained based on the oil flow rate passing through the pressure reducing valve corresponding to each boosting valve in the controller at the current moment;

[0007] Determine the oil volume of each wheel cylinder at the next moment based on the oil volume flowing into and out of each wheel cylinder at the current moment and the oil volume of each wheel cylinder at the previous moment;

[0008] Based on the preset volume-pressure change relationship and the oil volume of each wheel cylinder at the next moment, the wheel cylinder pressure of each wheel cylinder at the next moment is determined.

[0009] In one embodiment, obtaining the volume of oil flowing into the wheel cylinder corresponding to each boost valve at the current moment based on the oil flow rate passing through each boost valve in the controller at the current moment includes:

[0010] Get the working mode of the controller at the current moment;

[0011] According to the working mode of the controller, the oil flow rate passing through each boost valve at the current moment is determined;

[0012] The equivalent volume of the oil flow passing through each boost valve is determined as the volume of oil flowing into the wheel cylinder corresponding to each boost valve at the current moment.

[0013] In one embodiment, determining the oil flow rate passing through each boost valve at a current moment according to the operating mode of the controller includes:

[0014] If the controller is in passive boost mode, the current oil flow rate through each boost valve is determined based on the current wheel cylinder pressure, pump outlet pressure, and the opening area of each boost valve. The pump outlet pressure represents the pressure of the boost valve and pressure limiting valve.

[0015] If the working mode of the controller is the passive pressure reducing mode, it is determined that the oil flow rate passing through each boost valve at the current moment is 0.

[0016] In one embodiment, the controller includes two symmetrical main lines, one of which includes two wheel cylinders. Determining the oil flow rate passing through each boost valve at a current moment based on an operating mode of the controller includes:

[0017] For any main line, if the controller is in active boost mode, the oil flow rate passing through the pressure-limiting valve at the current moment is determined based on the current pump outlet pressure, master cylinder pressure, and the opening area of the pressure-limiting valve.

[0018] Obtain the oil flow rate flowing out of the plunger pump at the current moment, and determine the oil flow rate entering the main line after the pump at the current moment based on the oil flow rate passing through the pressure limiting valve and the oil flow rate flowing out of the plunger pump at the current moment;

[0019] Determining the wheel cylinder that needs to be pressurized at the current moment based on the wheel cylinder pressure of each wheel cylinder at the previous moment and a preset target pressure;

[0020] The current oil flow rate passing through each pressure-boosting valve is determined based on the current oil flow rate entering the main line after the pump and the number of wheel cylinders requiring pressure boost.

[0021] In one embodiment, the current oil flow rate through each boost valve is determined based on the current oil flow rate after the pump entering the main line and the number of wheel cylinders requiring boosting, including:

[0022] If the number of wheel cylinders requiring boosting is one, the oil flow rate after the pump entering the main line at the current moment is determined as the oil flow rate passing through the boost valve corresponding to the wheel cylinder requiring boosting at the current moment;

[0023] If there are two wheel cylinders that require boosting, the current oil flow rate through each boost valve is determined based on the oil volume of each wheel cylinder at the previous moment and the oil flow rate after the pump enters the main line at the current moment.

[0024] In one embodiment, the controller includes two symmetrical main lines, one of which includes two wheel cylinders. Determining the oil flow rate passing through each boost valve at a current moment based on an operating mode of the controller includes:

[0025] For any main line, if the controller's operating mode is active pressure reduction mode, the oil flow rate flowing out of the main line's pump at the current moment is determined based on the oil flow rate passing through the pressure limiting valve at the current moment;

[0026] Determining the wheel cylinder that needs to be decompressed at the current moment based on the wheel cylinder pressure of each wheel cylinder at the previous moment and a preset target pressure;

[0027] The current oil flow rate passing through each pressure-increasing valve is determined based on the current oil flow rate flowing out of the pump of the main line and the number of wheel cylinders that need to be decompressed.

[0028] In one embodiment, the current oil flow rate through each boost valve is determined based on the current oil flow rate flowing out of the pump of the main line and the number of wheel cylinders that need to be decompressed, including:

[0029] If the number of wheel cylinders requiring decompression is one, the flow rate of the oil flowing out of the pump of the main line at the current moment is determined as the flow rate passing through the boost valve corresponding to the wheel cylinder requiring decompression at the current moment;

[0030] If there are two wheel cylinders requiring decompression, the current oil flow rate through each boost valve is determined based on the oil volume of each wheel cylinder at the previous moment and the oil flow rate after flowing out of the main line pump at the current moment.

[0031] In one embodiment, obtaining the oil volume flowing out of each wheel cylinder at the current moment based on the oil flow rate passing through the pressure reducing valve corresponding to each boosting valve in the controller at the current moment includes:

[0032] Obtaining the current wheel cylinder pressure of each wheel cylinder, the pressure of each accumulator in the controller, and the opening area of each pressure reducing valve;

[0033] Determining the oil flow rate through each pressure reducing valve based on the current wheel cylinder pressure of each wheel cylinder, the pressure of each accumulator in the controller, and the opening area of each pressure reducing valve;

[0034] The equivalent volume of the oil flow passing through each pressure reducing valve is determined as the oil outflow volume of each wheel cylinder at the current moment.

[0035] In one embodiment, determining the oil volume of each wheel cylinder at a next moment based on the oil volume flowing into and out of each wheel cylinder at a current moment and the oil volume of each wheel cylinder at a previous moment includes:

[0036] Get the oil volume of the accumulator at the last moment;

[0037] If the accumulator's oil volume at the previous moment is less than the accumulator's maximum oil volume threshold, the oil volume of each wheel cylinder at the next moment is determined based on the current oil volume flowing into and out of each wheel cylinder and the oil volume of each wheel cylinder at the previous moment.

[0038] If the oil volume of the accumulator at the previous moment is greater than or equal to the maximum oil volume threshold of the accumulator, the oil flow rate flowing out of the accumulator at the current moment is obtained, and the oil volume of each wheel cylinder at the next moment is determined based on the inflow oil volume, outflow oil volume, flow rate flowing out of the accumulator, and the oil volume of each wheel cylinder at the previous moment.

[0039] In one embodiment, obtaining the oil flow rate flowing out of the accumulator at a current moment includes:

[0040] Obtain the average oil flow rate of the plunger pump, the oil flow rate through the suction valve, and the oil volume of the accumulator at the current moment;

[0041] The oil flow rate flowing out of the accumulator at the current moment is determined based on the average oil flow rate of the plunger pump at the current moment, the oil flow rate passing through the suction valve, and the oil volume of the accumulator.

[0042] In a second aspect, the present application further provides a wheel cylinder pressure determination device, the device comprising:

[0043] an acquisition module, configured to acquire the current volume of oil flowing into the wheel cylinder corresponding to each boosting valve based on the current oil flow rate passing through each boosting valve in the controller; and to acquire the current volume of oil flowing out of each wheel cylinder based on the current oil flow rate passing through the pressure reducing valve corresponding to each boosting valve in the controller;

[0044] An updating module, configured to determine the oil volume of each wheel cylinder at a next moment based on the oil volume flowing into and out of each wheel cylinder at a current moment and the oil volume of each wheel cylinder at a previous moment;

[0045] The determination module is used to determine the wheel cylinder pressure of each wheel cylinder at the next moment based on a preset volume-pressure change relationship and the oil volume of each wheel cylinder at the next moment.

[0046] In a third aspect, an embodiment of the present application provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of any one of the methods provided in the embodiment of the first aspect are implemented.

[0047] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the methods provided in the embodiment of the first aspect above.

[0048] In a fifth aspect, an embodiment of the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the steps of any one of the methods provided in the embodiments of the first aspect above.

[0049] An embodiment of the present application provides a method for determining wheel cylinder pressure, which obtains the inflowing oil volume of the wheel cylinder corresponding to each boosting valve at the current moment according to the oil flow passing through each boosting valve in the controller at the current moment, and obtains the outflowing oil volume of each wheel cylinder at the current moment according to the oil flow passing through the pressure reducing valve corresponding to each boosting valve in the controller at the current moment, and determines the oil volume of each wheel cylinder at the next moment according to the inflowing oil volume, the outflowing oil volume of each wheel cylinder at the current moment and the oil volume of each wheel cylinder at the previous moment, and then determines the wheel cylinder pressure of each wheel cylinder at the next moment based on a preset volume-pressure change relationship and the oil volume of each wheel cylinder at the next moment. In this method, the inflow oil volume flowing into each wheel cylinder corresponding to each boosting valve is determined according to the oil flow rate passing through each boosting valve, and the outflow oil volume flowing out of each wheel cylinder corresponding to each pressure reducing valve is determined according to the oil flow rate passing through each pressure reducing valve. Then, the volume of each wheel cylinder at the next moment is updated according to the outflow oil volume and inflow oil volume of each wheel cylinder at the current moment, and the wheel cylinder pressure of each wheel cylinder at the next moment is directly determined according to the preset volume-pressure change relationship. This method realizes the determination of the wheel cylinder pressure of the wheel cylinder without the need for a wheel cylinder pressure sensor, saves costs, avoids safety hazards caused by failure of the wheel cylinder pressure sensor, and utilizes the flow relationship of the oil flow rate to ensure the accuracy of the calculated wheel cylinder pressure of the wheel cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A diagram illustrating an application environment of a method for determining wheel cylinder pressure in one embodiment;

[0051] Figure 2 is a schematic flow chart of a method for determining wheel cylinder pressure in one embodiment;

[0052] Figure 3 2. It is a schematic structural diagram of a hydraulic control unit in one embodiment;

[0053] Figure 4 A schematic diagram of the relationship between volume and pressure changes in a method for determining wheel cylinder pressure in one embodiment;

[0054] Figure 5 is a flow chart of a method for determining wheel cylinder pressure in another embodiment;

[0055] Figure 6 is a flow chart of a method for determining wheel cylinder pressure in another embodiment;

[0056] Figure 7 is a flow chart of a method for determining wheel cylinder pressure in another embodiment;

[0057] Figure 8 is a flow chart of a method for determining wheel cylinder pressure in another embodiment;

[0058] Figure 9 A schematic diagram of the relationship between volume and pressure changes in a method for determining wheel cylinder pressure in another embodiment;

[0059] Figure 10 is a flow chart of a method for determining wheel cylinder pressure in another embodiment;

[0060] Figure 11 is a flow chart of a method for determining wheel cylinder pressure in another embodiment;

[0061] Figure 12 A schematic diagram of the relationship between volume and pressure changes in a method for determining wheel cylinder pressure in another embodiment;

[0062] Figure 13 is a flow chart of a method for determining wheel cylinder pressure in another embodiment;

[0063] Figure 14 is a flow chart of a method for determining wheel cylinder pressure in another embodiment;

[0064] Figure 15 is a flow chart of a method for determining wheel cylinder pressure in another embodiment;

[0065] Figure 16 FIG. 1 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0067] The wheel cylinder pressure determination method provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown, controller 102 communicates with server 104 via a network. A data storage system can store data that server 104 needs to process. The data storage system can be integrated with server 104 or placed on a cloud or other network server. Controller 102 can be, but is not limited to, a controller for various vehicle braking systems, such as an electronic hydraulic braking system. Server 104 can be implemented as a standalone server or a server cluster consisting of multiple servers.

[0068] An embodiment of the present application provides a method for determining wheel cylinder pressure, which can reduce the cost of obtaining wheel cylinder pressure.

[0069] The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments.

[0070] In one embodiment, a wheel cylinder pressure determination method is provided for use in Figure 1 Taking the application environment in as an example, this embodiment involves determining the oil volume of each wheel cylinder at the next moment based on the oil volume flowing into and out of each wheel cylinder at the current moment and the oil volume of each wheel cylinder at the previous moment, and then determining the wheel cylinder pressure of each wheel cylinder at the next moment based on the preset volume-pressure change relationship and the oil volume of each wheel cylinder at the next moment, as shown in the specific process. Figure 2 As shown, this embodiment includes the following steps:

[0071] S201, based on the oil flow passing through each boost valve in the controller at the current moment, obtain the volume of oil flowing into the wheel cylinder corresponding to each boost valve at the current moment; and based on the oil flow passing through the pressure reducing valve corresponding to each boost valve in the controller at the current moment, obtain the volume of oil flowing out of each wheel cylinder at the current moment.

[0072] Taking the electronic hydraulic control system as an example, the controller may be a hydraulic control unit (HCU), such as Figure 3 As shown, Figure 3 This is a schematic diagram of the hydraulic control unit (HCU). The HCU consists of two symmetrical main lines. The motor inside the HCU is a permanent magnet DC motor, driving the plunger pumps on both sides. EV is the boost valve, and RV is the pressure-limiting valve. Both the RV and EV are normally open valves controlled by pulse width modulation (PWM) duty cycle. A check valve CV is connected in parallel to the EV to facilitate reverse flow of oil. SV is the suction valve, and AV is the pressure-reducing valve. Both SV and AV are normally closed valves controlled by switches. Taking one of the main lines as an example, it can be structurally divided into a pre-pump section, a post-pump section, and a rear-wheel section. The pre-pump section includes the suction valve, plunger pump, and accumulator; the post-pump section includes the pressure-limiting valve and boost valve; and the rear-wheel section includes the pressure-reducing valve and wheel cylinder.

[0073] See Figure 3 The boost valve and the pressure reducing valve are devices for regulating the wheel cylinder pressure. The boost valve is used to increase the wheel cylinder pressure, and the pressure reducing valve is used to reduce the wheel cylinder pressure.

[0074] Among them, one wheel cylinder corresponds to a boost valve and a pressure reducing valve, and the boost valve and the pressure reducing valve work together to adjust the pressure of the corresponding wheel cylinder.

[0075] Therefore, when determining the pressure of the wheel cylinder, we can first obtain the oil flow through each boosting valve and the oil flow through the pressure reducing valve corresponding to each boosting valve in the controller at the current moment. Then, based on the oil flow through each boosting valve, we can obtain the inflow volume of the wheel cylinder corresponding to each boosting valve at the current moment. Based on the oil flow through the pressure reducing valve corresponding to each boosting valve, we can obtain the outflow volume of the wheel cylinder corresponding to each pressure reducing valve at the current moment.

[0076] The oil flow rate passing through each boost valve and each pressure reducing valve at the current moment can be determined through the oil flow rate change relationship of other components in the controller, such as the pressure limiting valve, the plunger pump and the accumulator. Then, based on the oil flow rate passing through each boost valve, the inflow volume of the wheel cylinder corresponding to each boost valve at the current moment is calculated. Based on the oil flow rate passing through the pressure reducing valve corresponding to each boost valve, the outflow volume of the wheel cylinder corresponding to each pressure reducing valve at the current moment is calculated.

[0077] Optionally, the oil flow through each boost valve can be obtained in real time through a sensor. Therefore, the oil flow through each boost valve in the controller at the current moment can be obtained based on the sensor, and then the volume of oil flowing into the wheel cylinder corresponding to each boost valve at the current moment can be further determined based on the time interval between the next moment and the previous moment.

[0078] For example, if the oil flow through each boost valve in the controller at the current moment is The volume of oil flowing into the wheel cylinder corresponding to each boost valve at the current moment can be expressed as in, It represents the oil flow rate passing through boost valve i at time k, and Δt represents the time interval between the next moment and the previous moment of time k.

[0079] The oil flow through each pressure reducing valve can also be obtained in real time through the sensor. Therefore, the oil flow through each pressure reducing valve in the controller at the current moment can be obtained based on the sensor, and then the outflow oil volume of the wheel cylinder corresponding to each pressure reducing valve at the current moment can be further determined based on the time interval between the next moment and the previous moment.

[0080] For example, if the oil flow through each pressure reducing valve in the controller at the current moment is The volume of oil flowing out of the wheel cylinder corresponding to each pressure reducing valve at the current moment can be expressed as in, It represents the oil flow rate passing through pressure reducing valve i at time k, and Δt represents the time interval between the next moment and the previous moment of time k.

[0081] S202 : Determine the oil volume of each wheel cylinder at the next moment based on the oil volume flowing into and out of each wheel cylinder at the current moment and the oil volume of each wheel cylinder at the previous moment.

[0082] Optionally, based on the inflow and outflow volumes of oil in each wheel cylinder at the current moment, the oil volume change value of each wheel cylinder at the current moment can be obtained, and then based on the oil volume of each wheel cylinder at the previous moment and the oil volume change value of each wheel cylinder at the current moment, the oil volume of each wheel cylinder at the next moment can be obtained.

[0083] It should be noted that the previous moment, the current moment and the next moment are consecutive moments, and the current moment is the middle moment between the previous moment and the next moment.

[0084] Alternatively, the previous moment can be approximately considered as the current moment. For example, the volume of oil flowing into each wheel cylinder at the current moment is The oil volume flowing out of each wheel cylinder at the current moment The oil volume of each wheel cylinder at the previous moment is Therefore, the oil volume of each wheel cylinder at the next moment is:

[0085]

[0086] S203 : Determine the wheel cylinder pressure of each wheel cylinder at the next moment based on the preset volume-pressure change relationship and the oil volume of each wheel cylinder at the next moment.

[0087] Based on the above-obtained oil volume of each wheel cylinder at the next moment and the preset volume-pressure change relationship, the wheel cylinder pressure of each wheel cylinder at the next moment is obtained.

[0088] The wheel cylinder pressure of each wheel cylinder at the next moment can be determined by directly obtaining the wheel cylinder pressure of each wheel cylinder at the next moment based on a preset curve diagram of the volume-pressure change relationship, such as Figure 4 As shown, Figure 4 The schematic diagram of the relationship between volume and pressure changes, where each wheel cylinder corresponds to a different change curve. The wheel cylinders include the front wheel cylinder and the rear wheel cylinder. The volume of the front wheel cylinder at time k+1 is The corresponding wheel cylinder pressure at time k+1 is The volume of the rear wheel cylinder at time k+1 is The corresponding wheel cylinder pressure at time k+1 is

[0089] In one embodiment, the wheel cylinder pressure of each wheel cylinder at the next moment can also be determined by a preset neural network model. The neural network model represents the relationship between volume and pressure changes. Specifically, the oil volume of each wheel cylinder at the next moment is input into the preset neural network model, and finally the wheel cylinder pressure of each wheel cylinder at the next moment is output.

[0090] The above-mentioned method for determining the wheel cylinder pressure obtains the volume of oil flowing into the wheel cylinder corresponding to each boosting valve at the current moment based on the oil flow passing through each boosting valve in the controller at the current moment, and obtains the volume of oil flowing out of each wheel cylinder at the current moment based on the oil flow passing through the pressure reducing valve corresponding to each boosting valve in the controller at the current moment, and determines the oil volume of each wheel cylinder at the next moment based on the oil volume flowing in and out of the wheel cylinder at the current moment and the oil volume of each wheel cylinder at the previous moment, and then determines the wheel cylinder pressure of each wheel cylinder at the next moment based on the preset volume-pressure change relationship and the oil volume of each wheel cylinder at the next moment. In this method, the inflow oil volume flowing into each wheel cylinder corresponding to each boosting valve is determined according to the oil flow rate passing through each boosting valve, and the outflow oil volume flowing out of each wheel cylinder corresponding to each pressure reducing valve is determined according to the oil flow rate passing through each pressure reducing valve. Then, the volume of each wheel cylinder at the next moment is updated according to the outflow oil volume and inflow oil volume of each wheel cylinder at the current moment, and the wheel cylinder pressure of each wheel cylinder at the next moment is directly determined according to the preset volume-pressure change relationship. This method realizes the determination of the wheel cylinder pressure of the wheel cylinder without the need for a wheel cylinder pressure sensor, saves costs, avoids safety hazards caused by failure of the wheel cylinder pressure sensor, and utilizes the flow relationship of the oil flow rate to ensure the accuracy of the calculated wheel cylinder pressure of the wheel cylinder.

[0091] In one embodiment, Figure 5 As shown, according to the oil flow rate passing through each boost valve in the controller at the current moment, obtaining the oil volume flowing into the wheel cylinder corresponding to each boost valve at the current moment includes the following steps:

[0092] S501, obtaining the current working mode of the controller.

[0093] Due to the complexity of the controller, when obtaining the oil flow rate passing through each boost valve in the controller at the current moment, the oil flow rate passing through each boost valve of the controller should be calculated in different modes.

[0094] The following describes how to determine the working mode at the current moment through an embodiment. In one embodiment, if the master cylinder pressure at the current moment is greater than the wheel cylinder pressure of each wheel cylinder and the components in the controller are not energized, the working mode of the controller is determined to be the passive boosting mode; if the master cylinder pressure at the current moment is greater than the wheel cylinder pressure of each wheel cylinder and the pressure reducing valve and the plunger pump in the controller are energized, the working mode of the controller is determined to be the passive decompression mode; if the master cylinder pressure at the current moment is less than or equal to the wheel cylinder pressure of each wheel cylinder and the boosting valve, suction valve, pressure limiting valve and plunger pump in the controller are all energized, the working mode of the controller is determined to be the active boosting mode; if the master cylinder pressure at the current moment is less than or equal to the wheel cylinder pressure of each wheel cylinder and the pressure limiting valve in the controller is energized, the working mode of the controller is determined to be the active decompression mode.

[0095] S502: Determine the oil flow rate passing through each boost valve at the current moment according to the working mode of the controller.

[0096] The oil flow rate passing through each boost valve at the current moment is determined according to different working modes of the controller. Different working modes determine the oil flow rate passing through each boost valve in different ways.

[0097] Optionally, the oil flow rate passing through each boost valve at the current moment is determined by using preset algorithms corresponding to different working modes.

[0098] S503 : Determine the equivalent volume of the oil flow passing through each boosting valve as the volume of oil flowing into the wheel cylinder corresponding to each boosting valve at the current moment.

[0099] Based on the above-mentioned oil flow through each boost valve, since the oil passing through the boost valve flows to the corresponding wheel cylinder, the equivalent volume of the oil flow through each boost valve can be determined as the oil volume flowing into the wheel cylinder corresponding to each boost valve at the current moment. According to the oil flow and time passing through each boost valve, the equivalent volume of the oil flow through each boost valve can be determined Then the equivalent volume of the oil flow through each boost valve is used as the oil volume flowing into the wheel cylinder corresponding to each boost valve at the current moment.

[0100] The above-mentioned wheel cylinder pressure determination method obtains the current controller operating mode and, based on the controller operating mode, determines the current oil flow rate through each boost valve. The equivalent volume of the oil flow rate through each boost valve is then determined as the current oil volume flowing into the corresponding wheel cylinder of each boost valve. In this method, the current oil flow rate through each boost valve is determined based on the controller operating mode to determine the current oil volume flowing into the corresponding wheel cylinder of each boost valve. Determining the wheel cylinder oil volume using a software model further allows for determining wheel cylinder volume changes, enabling wheel cylinder pressure determination without the use of wheel cylinder pressure sensors, thereby reducing costs.

[0101] In one embodiment, Figure 6 As shown, according to the working mode of the controller, determining the oil flow rate passing through each boost valve at the current moment includes the following steps:

[0102] S601: If the controller's operating mode is the passive boosting mode, the oil flow rate passing through each boosting valve at the current moment is determined based on the wheel cylinder pressure of each wheel cylinder, the pump-out pressure, and the opening area of each boosting valve at the current moment; the pump-out pressure represents the pressure of the boosting valve and the pressure-limiting valve.

[0103] First, if the controller is operating in the passive boost mode, the wheel cylinder pressure, pump outlet pressure, and opening area of each boost valve of each wheel cylinder at the current moment are obtained.

[0104] Optionally, the wheel cylinder pressure of each boosting valve at the current moment may be obtained from a stored database, and the opening area of each boosting valve may be determined according to an input control instruction of each boosting valve.

[0105] The pump-out pressure of the controller at the current moment can be determined according to the master cylinder pressure of the controller at the current moment; the pump-out pressure represents the pressure of the boost valve and the pressure limiting valve.

[0106] The input control instruction of each boost valve may be an input duty cycle of each boost valve, and then the opening area of each boost valve is determined according to the input duty cycle of each boost valve.

[0107] In one embodiment, obtaining the opening area of each boost valve at the current moment includes: first, determining the overflow pressure difference and saturation pressure difference of each boost valve at the current moment according to the input duty cycle of each boost valve at the current moment, and determining the displacement of the valve core of each boost valve at the current moment according to the overflow pressure difference and saturation pressure difference of each boost valve at the current moment, and then determining the opening area of each boost valve at the current moment according to the displacement of the valve core of each boost valve at the current moment.

[0108] Specifically, since the boost valve is a normally open valve, the opening area of the boost valve can be estimated using the relief valve model represented by an algebraic equation. First, the relief pressure difference Δp of the valve can be calculated according to formula (2): c and saturation pressure difference Δp s :

[0109]

[0110] Among them, K u , K x is the duty cycle coefficient and displacement coefficient of the electromagnetic force; u ov Enter the duty cycle for the normally open valve; K s is the spring stiffness, x ovm is the maximum displacement of the normally open valve, F s0 is the spring preload, α is the valve seat semi-cone angle, r v is the valve core radius.

[0111] Therefore, the input duty cycle of each boost valve at the current moment can be substituted into formula (2) to calculate the overflow pressure difference of each boost valve at the current moment: and saturation pressure difference

[0112] In the overflow valve model, the displacement x of the normally open valve core can be calculated using formula (3): ov , formula (3) can be expressed as:

[0113]

[0114] Where Δpov is the difference between the inlet and outlet pressures of the normally open valve, Δp ov =P ov_in -P ov_out , P ov_in is the normally open valve inlet pressure, P ov_out It is the outlet pressure of the normally open valve.

[0115] Therefore, the overflow pressure difference and saturation pressure difference of each boosting valve at the current moment are substituted into formula (3), and the displacement of the valve core of each boosting valve at the current moment is calculated based on the difference between the inlet and outlet pressures of each boosting valve.

[0116] In the overflow valve model, the opening area A of the normally open valve can be calculated using formula (4): ov , formula (4) can be expressed as:

[0117] A ov =πx ov cosα(r v +x ov cosα)sinα (4)

[0118] Among them, x ov is the displacement of the normally open valve core, α is the semi-cone angle of the valve seat, r v is the valve core radius.

[0119] Therefore, the displacement of the valve core of each boosting valve at the current moment, as well as the valve seat semi-cone angle and valve core radius of each boosting valve are substituted into formula (4) to calculate the opening area of each boosting valve.

[0120] Please continue to see Figure 3 During passive supercharging, due to the presence of the one-way valve CV3, the pump-out pressure is consistent with the master cylinder pressure. Therefore, the master cylinder pressure of the controller at the current moment is used as the pump-out pressure of the controller at the current moment.

[0121] in, represents the pressure after the pump at time k, represents the master cylinder pressure at time k.

[0122] In the passive boost mode, the oil flow rate through each boost valve can be calculated according to formula (5) based on the wheel cylinder pressure, pump pressure and opening area of each boost valve at the current moment.

[0123]

[0124] in, represents the pressure after the pump at time k, represents the wheel cylinder pressure of wheel cylinder i at time k, i = 1, 2, representing each wheel cylinder, represents the overflow pressure difference of each booster valve at time k, c q is the flow coefficient, ρ is the oil density, represents the opening area of each boost valve at time k, It represents the oil flow rate passing through each boost valve at time k.

[0125] According to the above formula (5), the wheel cylinder pressure, pump pressure, opening area of each boost valve, overflow pressure difference, flow coefficient and oil density of each boost valve at the current moment are substituted into formula (5) to obtain the oil flow rate passing through each boost valve at the current moment.

[0126] S602: If the working mode of the controller is the passive pressure reduction mode, determine that the oil flow rate passing through each boost valve at the current moment is 0.

[0127] When the working mode of the controller is the passive pressure reducing mode, each boost valve is in a closed state, and no oil flow passes through each boost valve. Therefore, if the working mode of the controller is the passive pressure increasing mode at the current moment, the oil flow passing through each boost valve at the current moment is 0.

[0128] In the aforementioned wheel cylinder pressure determination method, if the controller is operating in passive boost mode, the current oil flow rate through each boost valve is determined based on the current wheel cylinder pressure, pump outlet pressure, and the opening area of each boost valve. Pump outlet pressure represents the pressure of the boost valve and pressure-limiting valve. If the controller is operating in passive pressure-reducing mode, the current oil flow rate through each boost valve is determined to be zero. This method achieves redundancy in wheel cylinder pressure sensors and reduces the cost of obtaining wheel cylinder pressure.

[0129] In one embodiment, Figure 7 As shown, the controller includes two symmetrical main lines, one of which includes two wheel cylinders. According to the working mode of the controller, the oil flow rate passing through each boost valve at the current moment is determined, including:

[0130] S701, for any main line, if the controller's working mode is active boost mode, determine the oil flow rate passing through the pressure limiting valve at the current moment based on the current pump pressure, master cylinder pressure, and opening area of the pressure limiting valve.

[0131] Please continue to see Figure 3 , Figure 3 The controller includes two symmetrical main pipes, one of which includes two wheel cylinders. Since the two main pipes are symmetrical, one main pipe is used as an example for description.

[0132] For any main line, if the controller works in active boost mode, it is necessary to obtain the oil flow passing through the pressure limiting valve at the current moment.

[0133] The oil flow of the pressure limiting valve at the current moment can be obtained through formula (6).

[0134]

[0135] in, represents the oil flow through the pressure limiting valve at time k, c q is the flow coefficient, represents the opening area of the pressure limiting valve at time k, represents the pressure after the pump at time k, represents the master cylinder pressure at time k, Represents the relief pressure difference of each pressure limiting valve at time k.

[0136] Optionally, the opening area of the pressure limiting valve at the current moment can be calculated according to formulas (2)-(4), and the calculation method is the same as the method for calculating the opening area of the boost valve, which will not be repeated here.

[0137] If the controller is in active boost mode at the moment, the pump pressure at the moment is The calculation method is Right now Figure 3 , the pump-out pressure is the maximum value of the wheel cylinder pressures of the corresponding wheel cylinder 1 and wheel cylinder 2.

[0138] Therefore, the pump pressure, master cylinder pressure, and opening area of the pressure limiting valve at the current moment, as well as the flow coefficient of the pressure limiting valve, the overflow pressure difference of the pressure limiting valve at the current moment, and the opening area are substituted into formula (6) to calculate the oil flow rate passing through the pressure limiting valve at the current moment.

[0139] S702, obtaining the oil flow rate flowing out of the plunger pump at the current moment, and determining the oil flow rate after entering the main line pump at the current moment based on the oil flow rate passing through the pressure limiting valve and the oil flow rate flowing out of the plunger pump at the current moment.

[0140] In one embodiment, the method for obtaining the oil flow rate flowing out of the plunger pump at the current moment can be, first, obtaining the motor speed of the motor in the controller at the current moment, and determining the average oil flow rate of the plunger pump at the current moment based on the motor speed of the motor in the controller at the current moment, and determining the pressure difference at both ends of the suction valve at the current moment based on the pressure of the accumulator and the master cylinder pressure at the current moment, and obtaining the opening area of the suction valve at the current moment, and determining the oil flow rate passing through the suction valve at the current moment based on the pressure difference and opening area at both ends of the suction valve at the current moment, and then determining the oil flow rate flowing out of the plunger pump at the current moment based on the average oil flow rate of the plunger pump at the current moment, the oil flow rate passing through the suction valve and the oil volume of the accumulator.

[0141] An input instruction of the motor in the controller at the current moment is obtained. Optionally, the input instruction may be an input duty cycle of the motor. Then, a motor speed of the motor in the controller at the current moment is determined according to the input instruction of the motor in the controller at the current moment.

[0142] Since the rotational inertia of the DC motor in the controller is small and the inertia of the electronic system is very small compared to the mechanical system, the transient characteristics of the motor in the controller can be ignored and the motor speed can be expressed by formula (7).

[0143]

[0144] Among them, i m is the motor current, ω is the motor speed, u im is the input duty cycle of the DC motor, U bat is the supply voltage, R m is the armature resistance, K e is the back electromotive force coefficient, K t is the torque coefficient, K f is the motor damping coefficient, T L is the motor load torque.

[0145] Motor load torque T L It can be approximately expressed by formula (8).

[0146]

[0147] Among them, d m is the plunger diameter; e is the eccentric distance of the eccentric wheel; θ is the motor rotation angle; P rI 、P rII These are the post-pump pressure values of pipelines I and II respectively.

[0148] By eliminating the two equations in equation (7) simultaneously, the motor speed ω can be obtained, which can be expressed by equation (9).

[0149]

[0150] Therefore, the input command of the motor in the controller at the current moment, that is, the input duty cycle u of the motor im Substituting into formula (9) and combining it with formula (8), the motor speed of the motor in the controller at the current moment can be obtained.

[0151] Based on the motor speed of the motor in the controller at the current moment obtained above, the average oil flow rate of the plunger pump at the current moment is calculated, as shown in formula (10).

[0152]

[0153] in, represents the average oil flow of the plunger pump at time k, V is the displacement, and n is the speed; η v is the volumetric efficiency. m is the plunger diameter; e is the eccentricity of the eccentric wheel, and ω is the motor speed.

[0154] Therefore, the motor speed of the motor in the controller at the current moment, as well as the plunger diameter, eccentricity of the eccentric wheel and volumetric efficiency of the plunger pump are substituted into formula (10) to obtain the average oil flow rate of the plunger pump at the current moment.

[0155] Optionally, the average oil flow rate of the plunger pump at the current moment is also the maximum pumping capacity of the plunger pump.

[0156] As shown in formula (11), the pressure difference between the two ends of the suction valve can be calculated using formula (11).

[0157]

[0158] in, Indicates the pressure difference at both ends of the suction valve at time k, represents the master cylinder pressure of the controller at time k, represents the pressure of the accumulator at time k, P p0 It means that a basically fixed negative pressure is generated at the inlet of the plunger pump.

[0159] Therefore, the accumulator pressure and the master cylinder pressure at the current moment, as well as the negative pressure generated at the plunger pump inlet, which is basically a fixed value, are substituted into formula (11), and the pressure difference between the two ends of the suction valve at the current moment is calculated.

[0160] In one embodiment, the opening area of the suction valve at the current moment can be obtained by obtaining the input duty cycle of each suction valve at the current moment, and then determining the opening area of each suction valve at the current moment based on the input duty cycle of each suction valve at the current moment.

[0161] Specifically, the input duty cycle of each suction valve at the current moment can be determined according to the input instruction of each suction valve at the current moment, and then the opening area of each suction valve at the current moment can be calculated according to formula (12).

[0162]

[0163] Among them, A cv A is the opening area of the normally closed valve, cvm is the maximum opening area; u cv Enter the duty cycle for a normally closed valve.

[0164] The suction valve is a normally closed valve. Therefore, the input duty cycle and maximum opening area of each suction valve at the current moment can be substituted into formula (12) to obtain the opening area of each suction valve at the current moment.

[0165] Optionally, the hovering position of the valve core of each suction valve at the current moment can also be determined according to the input duty cycle of each suction valve at the current moment, which can be calculated according to formula (13).

[0166]

[0167] Among them, x cv is the displacement of the normally closed valve core, x cvm is the maximum displacement of the normally closed valve, u cv Enter the duty cycle for a normally closed valve.

[0168] According to the Bernoulli equation, the oil flow rate passing through the suction valve at the current moment is calculated using the pressure difference between the two ends of the suction valve, the opening area, the flow coefficient and the oil density at the current moment. It can be calculated according to formula (14).

[0169]

[0170] in, represents the oil flow through the suction valve at time k, c q is the flow coefficient of the suction valve, represents the opening area of the suction valve at time k, It represents the pressure difference across the suction valve at time k, and ρ is the oil density.

[0171] Therefore, the flow coefficient, opening area, pressure difference between both ends and oil density of the suction valve at the current moment are substituted into formula (14) to calculate the oil flow rate passing through the suction valve at the current moment.

[0172] Based on the above-mentioned average oil flow rate of the plunger pump at the current moment, the oil flow rate through the suction valve, and the oil volume of the accumulator, the oil flow rate flowing out of the plunger pump at the current moment can be calculated, as shown in formula (15).

[0173]

[0174] in, represents the oil flow rate flowing out of the plunger pump at time k, represents the average oil flow of the plunger pump at time k, represents the oil volume of the accumulator at time k, It represents the oil flow rate passing through the suction valve at time k.

[0175] Therefore, based on the oil flow through the pressure limiting valve and the oil flow out of the plunger pump at the current moment, the oil flow after the pump entering the main line at the current moment can be determined by: Figure 3 , the oil flow through the pressure limiting valve is from the pump to the master cylinder in the positive direction. Therefore, the oil flow after the pump entering the main line at the current moment can be determined as shown in formula (16).

[0176]

[0177] in, It represents the oil flow rate after entering the main pipeline at time k. represents the oil flow rate flowing out of the plunger pump at time k, It represents the oil flow through the pressure limiting valve at time k, where the oil flow through the pressure limiting valve is from the pump of the main line to the master cylinder in the positive direction.

[0178] S703 : Determine the wheel cylinder that needs to be pressurized at the current moment based on the wheel cylinder pressure of each wheel cylinder at the previous moment and the preset target pressure.

[0179] Based on the wheel cylinder pressure of each wheel cylinder at the previous moment and the preset target pressure, the wheel cylinder that needs to be pressurized at the current moment is determined. Optionally, the wheel cylinder pressure of each wheel cylinder at the previous moment can be compared with the preset target pressure. If the wheel cylinder pressure of each wheel cylinder at the previous moment is less than the preset target pressure, it is determined that each wheel cylinder needs to be pressurized, that is, the wheel cylinder whose wheel cylinder pressure at the previous moment is less than the preset target pressure is determined as the wheel cylinder that needs to be pressurized at the current moment.

[0180] The preset target pressure may be a target pressure of an anti-lock braking system.

[0181] In one embodiment, if there is a wheel cylinder whose wheel cylinder pressure at the previous moment is less than the target pressure, and the number of wheel cylinders with wheel cylinder pressure less than the target pressure is one, then the wheel cylinder with wheel cylinder pressure less than the target pressure is determined as the wheel cylinder requiring pressurization at the current moment; if the wheel cylinder pressure of each wheel cylinder at the previous moment is less than the target pressure, then each wheel cylinder is determined as the wheel cylinder requiring pressurization at the current moment; if the wheel cylinder pressure of each wheel cylinder at the previous moment is greater than or equal to the target pressure, then there is no wheel cylinder requiring pressurization at the current moment.

[0182] For details, please see Figure 3 If the wheel cylinder pressure of wheel cylinder 1 at the previous moment was less than the target pressure, and the wheel cylinder pressure of wheel cylinder 2 at the previous moment was not less than the target pressure, wheel cylinder 1 is determined to be the wheel cylinder requiring pressure increase at the current moment. If the wheel cylinder pressure of wheel cylinder 2 at the previous moment was less than the target pressure, and the wheel cylinder pressure of wheel cylinder 1 at the previous moment was not less than the target pressure, wheel cylinder 2 is determined to be the wheel cylinder requiring pressure increase at the current moment. If the wheel cylinder pressures of both wheel cylinders 1 and 2 at the previous moment were less than the target pressure, both wheel cylinders 1 and 2 are required to be pressure increased. If the wheel cylinder pressures of both wheel cylinders 1 and 2 at the previous moment were greater than or equal to the target pressure, no wheel cylinder requires pressure increase at the current moment.

[0183] S704 : Determine the current oil flow rate passing through each pressure-boosting valve based on the current oil flow rate entering the main line after the pump and the number of wheel cylinders requiring pressure boosting.

[0184] Please continue to see Figure 3 , and taking a main line as an example, a main line includes two wheel cylinders: wheel cylinder 1 and wheel cylinder 2, and each wheel cylinder corresponds to a boost valve. Therefore, according to the oil flow rate after the pump entering the main line at the current moment and the number of wheel cylinders that need to be boosted, the method of determining the oil flow rate passing through each boost valve at the current moment can be: if the number of wheel cylinders that need to be boosted is 1, and the wheel cylinder that needs to be boosted is wheel cylinder 1, then the oil flow rate after the pump entering the main line at the current moment is determined as the oil flow rate passing through the boost valve EV1 corresponding to wheel cylinder 1 at the current moment. At this time, wheel cylinder 2 is not boosted, and the oil flow rate passing through the boost valve EV2 corresponding to wheel cylinder 2 is 0.

[0185] If the number of wheel cylinders that require boosting is two, indicating that both wheel cylinder 1 and wheel cylinder 2 require boosting, the oil flow after the pump entering the main line at the current moment flows into wheel cylinder 1 and wheel cylinder 2. The oil flow after the pump entering the main line at the current moment can be distributed to wheel cylinder 1 and wheel cylinder 2 in a certain proportion.

[0186] The above wheel cylinder pressure determination method, for any main circuit, determines the current oil flow through the pressure-limiting valve based on the current pump-out pressure, master cylinder pressure, and the opening area of the pressure-limiting valve if the controller is operating in active boost mode. The current oil flow out of the plunger pump is obtained, and the current oil flow after the pump entering the main circuit is determined based on the current oil flow through the pressure-limiting valve and the oil flow out of the plunger pump. The wheel cylinder to be boosted is then determined based on the wheel cylinder pressure of each wheel cylinder at the previous moment and a preset target pressure. The current oil flow through each boost valve is then determined based on the current oil flow after the pump entering the main circuit and the number of wheel cylinders to be boosted. This method accurately determines the current oil flow through each boost valve by analyzing the current oil flow of various controller components, ensuring the accuracy of the determined wheel cylinder pressures for each wheel cylinder.

[0187] In one embodiment, Figure 8 As shown, the oil flow rate passing through each boost valve at the current moment is determined based on the oil flow rate after the pump entering the main line at the current moment and the number of wheel cylinders that need to be boosted, including the following steps:

[0188] S801: If the number of wheel cylinders requiring boosting is one, the oil flow rate after the pump entering the main line at the current moment is determined as the oil flow rate passing through the boost valve corresponding to the wheel cylinder requiring boosting at the current moment.

[0189] If the number of wheel cylinders that need to be pressurized is one, the oil flow rate after the pump entering the main line at the current moment is the oil flow rate passing through the boost valve corresponding to the wheel cylinder that needs to be pressurized at the current moment. For example, continue to refer to Figure 3 If the wheel cylinder that needs to be boosted is wheel cylinder 2 and the boost valve corresponding to wheel cylinder 2 is EV2, then the oil flow rate after the pump entering the main line at the current moment is determined as the oil flow rate passing through the boost valve EV2 at the current moment. At this time, wheel cylinder 1 is not boosted, and the oil flow rate passing through the boost valve EV1 corresponding to wheel cylinder 1 is 0.

[0190] S802: If there are two wheel cylinders that require pressurization, determine the oil flow rate passing through each boost valve at the current moment based on the oil volume of each wheel cylinder at the previous moment and the oil flow rate after the pump enters the main line at the current moment.

[0191] The method for determining the oil flow rate passing through each boost valve at the current moment can be to determine the total oil volume of the wheel cylinders of the main line at the previous moment based on the oil volume of each wheel cylinder in the main line at the previous moment, and determine the total oil volume of the wheel cylinders of the main line at the next moment based on the total oil volume of the wheel cylinders of the main line at the previous moment and the oil flow rate after the pump entering the main line at the current moment, and then determine the oil flow rate passing through each boost valve at the current moment based on the relationship between the oil volume of each wheel cylinder in the main line at the previous moment, the total oil volume of the wheel cylinders of the main line at the next moment and the change in volume pressure.

[0192] Continue to see Figure 3 , according to the oil volume of wheel cylinder 1 and wheel cylinder 2 in the main line at the previous moment, the total oil volume of the wheel cylinders in the main line at the previous moment is determined, which can be calculated using formula (17).

[0193]

[0194] in, represents the total volume of oil in the wheel cylinder of the main pipeline at time k, represents the oil volume of wheel cylinder 1 in the main pipeline at time k, represents the oil volume of wheel cylinder 2 in the main line at time k.

[0195] According to the total oil volume of the wheel cylinders of the main line at the previous moment and the oil flow rate after entering the pump of the main line at the current moment, the total oil volume of the wheel cylinders of the main line at the next moment can be updated, as shown in formula (18).

[0196]

[0197] in, represents the total volume of oil in the wheel cylinder of the main line at time k+1, represents the total volume of oil in the wheel cylinder of the main pipeline at time k, It represents the oil flow rate after entering the main pipeline pump at time k, and Δt represents the time interval between the next moment and the previous moment, that is, the time amount at the current moment.

[0198] The method for determining the oil flow rate passing through each boost valve at the current moment based on the relationship between the oil volume of each wheel cylinder in the main line at the previous moment, the total oil volume of the wheel cylinders in the main line at the next moment, and the changing relationship between the volume pressure can be as follows: determining the pump-out pressure of the main line at the next moment based on the changing relationship between the volume pressure and the total oil volume of the wheel cylinders in the main line at the next moment, and then determining the oil volume of each wheel cylinder at the next moment based on the changing relationship between the volume pressure and the pump-out pressure of the main line at the next moment; and determining the oil flow rate passing through each boost valve at the current moment based on the oil volume of each wheel cylinder in the main line at the previous moment and the oil volume of each wheel cylinder at the next moment.

[0199] Specifically, the relationship between volume and pressure represents the relationship between the oil volume and the wheel cylinder pressure. Please refer to Figure 3 , Figure 3 is a diagram showing the relationship between volume and pressure. Therefore, according to the total volume of the oil in the wheel cylinder of the main line at the next moment and the relationship between volume and pressure, the pump pressure after the main line at the next moment can be determined. For example, Figure 9 As shown, Figure 9 in represents the total volume of oil in the wheel cylinder of the main line at the next time k+1 after time k, It represents the pump pressure of the main line at the next moment k+1 after the k moment.

[0200] The pump-out pressure of the main line at the next moment is also the wheel cylinder pressure of each wheel cylinder at the next moment. Therefore, according to the wheel cylinder pressure of each wheel cylinder at the next moment and combined with Figure 9 The oil volume of each wheel cylinder at the next moment can be determined, that is, and is the oil volume of wheel cylinder 1 and wheel cylinder 2 at the next moment, according to the oil volume of wheel cylinder 1 and wheel cylinder 2 at the next moment and The volume of boost valve EV1 and boost valve EV2 flowing into wheel cylinder 1 and wheel cylinder 2 at the current moment can be determined. Then, based on the volume of boost valve EV1 and boost valve EV2 flowing into wheel cylinder 1 and wheel cylinder 2, the oil flow rate passing through each boost valve at the current moment can be determined. The oil flow rate passing through boost valve 1 and boost valve 2 at the current moment can be calculated respectively according to formula (19).

[0201]

[0202] in, represents the oil flow through boost valve i at time k, represents the oil volume of wheel cylinder i at time k+1, represents the oil volume of wheel cylinder i at time k, i = 1, 2, and Δt represents the time interval between time k+1 and time k.

[0203] Optionally, continue with Figure 3 If both wheel cylinders in the main line need to be pressurized, the method for determining the oil flow rate passing through each boost valve at the current moment can be to divide the oil flow rate after the pump entering the main line at the current moment according to the ratio corresponding to the ratio based on the ratio of the oil volume of each wheel cylinder at the previous moment, and determine the oil flow rate passing through each boost valve at the current moment.

[0204] For example, if the ratio of the oil volumes of wheel cylinder 1 and wheel cylinder 2 at the previous moment is 1:2, then the oil flow after the pump entering the main line at the current moment is divided into three parts, two of which are determined as the oil flow passing through the boost valve EV1 corresponding to wheel cylinder 1 at the current moment, and one of which is determined as the oil flow passing through the boost valve EV2 corresponding to wheel cylinder 2 at the current moment.

[0205] The above wheel cylinder pressure determination method, if there is only one wheel cylinder requiring boost, determines the current oil flow rate after the pump entering the main circuit as the oil flow rate through the boost valve corresponding to the wheel cylinder requiring boost. If there are two wheel cylinders requiring boost, the current oil flow rate through each boost valve is determined based on the oil volume in each wheel cylinder at the previous moment and the current oil flow rate after the pump entering the main circuit. This method determines the oil flow rate through the boost valve corresponding to the wheel cylinder requiring boost based on the current oil flow rate after the pump entering the main circuit, improving the accuracy of active boosting in the controller.

[0206] In one embodiment, Figure 10 As shown, the controller includes two symmetrical main lines, one of which includes two wheel cylinders. According to the working mode of the controller, determining the oil flow rate passing through each boost valve at the current moment includes the following steps:

[0207] S1001: For any main line, if the working mode of the controller is the active pressure reducing mode, the oil flow rate flowing out of the main line after the pump at the current moment is determined based on the oil flow rate passing through the pressure limiting valve at the current moment.

[0208] Please continue to see Figure 3 , Figure 3 The controller includes two symmetrical main pipes, one of which includes two wheel cylinders. Since the two main pipes are symmetrical, one main pipe is used as an example for description.

[0209] For any main line, if the working mode of the controller is the active pressure reducing mode, it is necessary to obtain the oil flow passing through the pressure limiting valve at the current moment. The oil flow of the pressure limiting valve at the current moment can be obtained by formula (6), which is the same as the above-mentioned acquisition method and will not be repeated here.

[0210] Because in the active decompression process, only the pressure limiting valve is energized, the oil flow rate flowing out of the main line after the pump at the current moment is the oil flow rate passing through the pressure limiting valve at the current moment, so, It represents the oil flow rate after flowing out of the pump of the main line at time k.

[0211] S1002 , determining the wheel cylinder that needs to be decompressed at the current moment based on the wheel cylinder pressure of each wheel cylinder at the previous moment and a preset target pressure.

[0212] Based on the wheel cylinder pressure of each wheel cylinder at the previous moment and a preset target pressure, the wheel cylinder that needs to be decompressed at the current moment is determined. Optionally, the wheel cylinder pressure of each wheel cylinder at the previous moment can be compared with the preset target pressure. If the wheel cylinder pressure of each wheel cylinder at the previous moment is greater than the preset target pressure, it is determined that each wheel cylinder needs to be decompressed, that is, the wheel cylinder whose wheel cylinder pressure at the previous moment is greater than the preset target pressure is determined as the wheel cylinder that needs to be decompressed at the current moment.

[0213] The preset target pressure may be a target pressure of an anti-lock braking system.

[0214] The wheel cylinder requiring decompression may be determined by, if there is a wheel cylinder whose wheel cylinder pressure at a previous moment was greater than a target pressure, and the number of wheel cylinders having a wheel cylinder pressure greater than the target pressure is one, determining the wheel cylinder having a wheel cylinder pressure greater than the target pressure as the wheel cylinder requiring decompression at the current moment. If the wheel cylinder pressures of all wheel cylinders at the previous moment were greater than the target pressure, then each wheel cylinder is determined as the wheel cylinder requiring decompression at the current moment. If the wheel cylinder pressures of all wheel cylinders at the previous moment were less than or equal to the target pressure, then no wheel cylinder requiring decompression at the current moment exists.

[0215] For example, see Figure 3 If the wheel cylinder pressure of wheel cylinder 1 at the previous moment was greater than the target pressure, and the wheel cylinder pressure of wheel cylinder 2 at the previous moment was not greater than the target pressure, wheel cylinder 1 is determined as the wheel cylinder requiring decompression at the current moment; if the wheel cylinder pressure of wheel cylinder 2 at the previous moment was greater than the target pressure, and the wheel cylinder pressure of wheel cylinder 1 at the previous moment was not greater than the target pressure, wheel cylinder 2 is determined as the wheel cylinder requiring decompression at the current moment; if the wheel cylinder pressures of wheel cylinder 1 and wheel cylinder 2 at the previous moment were both greater than the target pressure, both wheel cylinder 1 and wheel cylinder 2 are the wheel cylinders requiring decompression; if the wheel cylinder pressures of wheel cylinder 1 and wheel cylinder 2 at the previous moment were both less than or equal to the target pressure, it indicates that no wheel cylinder requires decompression at the current moment.

[0216] S1003 , the current oil flow rate passing through each pressure-increasing valve is determined based on the current oil flow rate flowing out of the pump of the main line and the number of wheel cylinders requiring reduced pressure.

[0217] Please continue to see Figure 3 , and taking a main line as an example, a main line includes two wheel cylinders: wheel cylinder 1 and wheel cylinder 2, and each wheel cylinder corresponds to a boost valve. Therefore, based on the oil flow rate flowing out of the main line after the pump at the current moment and the number of wheel cylinders that need to be depressurized, the method of determining the oil flow rate passing through each boost valve at the current moment can be: if the number of wheel cylinders that need to be depressurized is 1, and the wheel cylinder that needs to be depressurized is wheel cylinder 1, then the oil flow rate flowing out of the main line after the pump at the current moment is determined as the oil flow rate passing through the boost valve EV1 corresponding to wheel cylinder 1 at the current moment. At this time, wheel cylinder 2 is not depressurized, and the oil flow rate passing through the boost valve EV2 corresponding to wheel cylinder 2 is 0.

[0218] If the number of wheel cylinders that need to be decompressed is two, indicating that both wheel cylinder 1 and wheel cylinder 2 need to be decompressed, then the oil flow rate after the pump flowing out of the main line at the current moment flows out of wheel cylinder 1 and wheel cylinder 2. The oil flow rate after the pump flowing out of the main line at the current moment can be distributed to wheel cylinder 1 and wheel cylinder 2 in a certain proportion.

[0219] The above wheel cylinder pressure determination method, for any main circuit, determines the current oil flow rate after exiting the main circuit's pump based on the current oil flow rate through the pressure-limiting valve if the controller is operating in active pressure reduction mode. The wheel cylinder requiring pressure reduction is determined based on the previous wheel cylinder pressure and a preset target pressure. The current oil flow rate through each boost valve is determined based on the current oil flow rate after exiting the main circuit's pump and the number of wheel cylinders requiring pressure reduction. This method accurately determines the current oil flow rate through each boost valve by analyzing the current oil flow rate of various controller components, ensuring the accuracy of the determined wheel cylinder pressure.

[0220] In one embodiment, Figure 11 As shown, the oil flow rate passing through each boost valve at the current moment is determined based on the oil flow rate flowing out of the pump of the main line at the current moment and the number of wheel cylinders that need to be decompressed, including the following steps:

[0221] S1101: If the number of wheel cylinders requiring decompression is one, the oil flow rate flowing out of the pump of the main line at the current moment is determined as the flow rate passing through the boost valve corresponding to the wheel cylinder requiring decompression at the current moment.

[0222] If the number of wheel cylinders that need to reduce pressure is one, the oil flow rate flowing out of the pump of the main line at the current moment is the oil flow rate passing through the boost valve corresponding to the wheel cylinder that needs to reduce pressure at the current moment. For example, continue to refer to Figure 3If the wheel cylinder that needs to be decompressed is wheel cylinder 2, and the boost valve corresponding to wheel cylinder 2 is EV2, then the oil flow rate flowing out of the main line after the pump at the current moment is determined as the oil flow rate passing through the boost valve EV2 at the current moment. At this time, wheel cylinder 1 does not reduce pressure, and the oil flow rate passing through the boost valve EV1 corresponding to wheel cylinder 1 is 0.

[0223] S1102: If there are two wheel cylinders that need to be decompressed, determine the oil flow rate passing through each boost valve at the current moment based on the oil volume of each wheel cylinder at the previous moment and the oil flow rate after flowing out of the main pipeline pump at the current moment.

[0224] The method for determining the oil flow rate passing through each boost valve at the current moment based on the oil volume of each wheel cylinder at the previous moment and the oil flow rate after flowing out of the pump of the main line at the current moment can be to determine the total oil volume of the wheel cylinders of the main line at the previous moment based on the oil volume of each wheel cylinder of the main line at the previous moment, and then determine the total oil volume of the wheel cylinders of the main line at the next moment based on the total oil volume of the wheel cylinders of the main line at the previous moment and the oil flow rate after flowing out of the pump of the main line at the current moment, and then determine the oil flow rate passing through each boost valve at the current moment based on the relationship between the oil volume of each wheel cylinder in the main line at the previous moment, the total oil volume of the wheel cylinders of the main line at the next moment and the change in volume pressure.

[0225] Specifically, the method for determining the total oil volume of the wheel cylinders of the main line at the previous moment is the same as the method for determining the total oil volume of the wheel cylinders of the main line at the previous moment in the above embodiment, which will not be described in detail here.

[0226] According to the total oil volume of the wheel cylinders of the main line at the previous moment and the oil flow rate after flowing out of the pump of the main line at the current moment, the total oil volume of the wheel cylinders of the main line at the next moment can be updated, as shown in formula (20).

[0227]

[0228] in, represents the total volume of oil in the wheel cylinder of the main line at time k+1, represents the total volume of oil in the wheel cylinder of the main pipeline at time k, It represents the oil flow rate after flowing out of the pump of the main line at time k, and Δt represents the time interval between the next moment and the previous moment, that is, the time amount at the current moment.

[0229] In one embodiment, the method for determining the oil flow rate passing through each boost valve at the current moment based on the relationship between the oil volume of each wheel cylinder in the main line at the previous moment, the total oil volume of the wheel cylinders in the main line at the next moment, and the changing relationship between the volume pressure can be as follows: determining the pump-out pressure of the main line at the next moment based on the changing relationship between the volume pressure and the total oil volume of the wheel cylinders in the main line at the next moment, and determining the oil volume of each wheel cylinder at the next moment based on the changing relationship between the volume pressure and the pump-out pressure of the main line at the next moment; determining the oil flow rate passing through each boost valve at the current moment based on the oil volume of each wheel cylinder in the main line at the previous moment and the oil volume of each wheel cylinder at the next moment.

[0230] Specifically, the relationship between volume and pressure represents the relationship between the oil volume and the wheel cylinder pressure. Please refer to Figure 3 , Figure 3 Schematic diagram of the relationship between volume and pressure changes. Therefore, according to the total volume of oil in the wheel cylinders of the main line at the next moment and the relationship between volume and pressure changes, the pump outlet pressure of the main line at the next moment can be determined.

[0231] For example, Figure 12 As shown, Figure 12 in represents the total volume of oil in the wheel cylinder of the main line at the next time k+1 after time k, The pump pressure of the main line at the next moment k+1 is represented by . The pump pressure of the main line at the next moment is also the wheel cylinder pressure of each wheel cylinder at the next moment. Therefore, according to the wheel cylinder pressure of each wheel cylinder at the next moment and combined with Figure 12 The oil volume of each wheel cylinder at the next moment can be determined, that is, and is the oil volume of wheel cylinder 1 and wheel cylinder 2 at the next moment, and the oil volume of wheel cylinder 1 and wheel cylinder 2 in the main line at the previous moment is and The volume of boost valve EV1 and boost valve EV2 flowing into wheel cylinder 1 and wheel cylinder 2 corresponding to the current moment can be determined. Then, based on the volume of boost valve EV1 and boost valve EV2 flowing into wheel cylinder 1 and wheel cylinder 2, the oil flow rate passing through each boost valve at the current moment can be determined. According to formula (21), the oil flow rate passing through boost valve 1 and boost valve 2 at the current moment can be calculated respectively.

[0232]

[0233] in, represents the oil flow through boost valve i at time k, represents the oil volume of wheel cylinder i at time k+1, Represents the oil volume of wheel cylinder i at time k, i = 1, 2.

[0234] Optionally, continue with Figure 3 If both wheel cylinders in the main line need to be decompressed, the method for determining the oil flow rate passing through each boost valve at the current moment can be to divide the oil flow rate flowing out of the main line pump at the current moment according to the ratio of the oil volume of each wheel cylinder at the previous moment according to the proportion corresponding to the ratio, and determine the oil flow rate passing through each boost valve at the current moment.

[0235] For example, if the ratio of the oil volumes of wheel cylinder 1 and wheel cylinder 2 at the previous moment is 1:2, then the oil flow rate after the pump flowing out of the main line at the current moment is divided into three parts, one of which is determined as the oil flow rate passing through the boost valve EV1 corresponding to wheel cylinder 1 at the current moment, and two of the parts are determined as the oil flow rate passing through the boost valve EV2 corresponding to wheel cylinder 2 at the current moment.

[0236] The above wheel cylinder pressure determination method, if there is only one wheel cylinder requiring decompression, determines the current flow rate of oil flowing out of the main line pump as the flow rate through the boost valve corresponding to the wheel cylinder requiring decompression. If there are two wheel cylinders requiring decompression, the current flow rate through each boost valve is determined based on the oil volume in each wheel cylinder at the previous moment and the current flow rate of oil flowing out of the main line pump. This method determines the oil flow rate through the boost valve corresponding to the wheel cylinder requiring decompression based on the current flow rate of oil flowing out of the main line pump, improving the accuracy of active decompression in the controller.

[0237] In one embodiment, Figure 13 As shown, according to the oil flow rate of the pressure reducing valve corresponding to each boost valve in the controller at the current moment, the outflow volume of the oil of each wheel cylinder at the current moment is obtained, including the following steps:

[0238] S1301: Obtain the current wheel cylinder pressure of each wheel cylinder, the pressure of each accumulator in the controller, and the opening area of each pressure reducing valve.

[0239] Alternatively, the wheel cylinder pressure of each wheel cylinder and the pressure of the accumulator at the current moment may be acquired from a stored database.

[0240] The opening area of each pressure reducing valve is determined according to the input duty cycle of each pressure reducing valve; the specific calculation method is the same as the calculation method of the opening area of each suction valve mentioned above, and will not be repeated here.

[0241] S1302 : Determine the oil flow rate passing through each pressure reducing valve based on the current wheel cylinder pressure of each wheel cylinder, the pressure of each accumulator in the controller, and the opening area of each pressure reducing valve.

[0242] The pressure reducing valve is a normally closed valve. The oil flow through the pressure reducing valve can be expressed as:

[0243]

[0244] in, represents the oil flow through pressure reducing valve i at time k, c q represents the flow coefficient, represents the opening area of pressure reducing valve i at time k, represents the wheel cylinder pressure of wheel cylinder i at time k, represents the pressure of the accumulator at time k.

[0245] Therefore, by substituting the wheel cylinder pressure of each wheel cylinder, the pressure of each accumulator in the controller, and the opening area of each pressure reducing valve into formula (22), the oil flow rate passing through each pressure reducing valve can be obtained.

[0246] S1303: Determine the equivalent volume of the oil flow passing through each pressure reducing valve as the oil outflow volume of each wheel cylinder at the current moment.

[0247] Based on the above-mentioned oil flow through each pressure reducing valve, since the oil passing through the pressure reducing valve flows out from the corresponding wheel cylinder, the equivalent volume of the oil flow through each pressure reducing valve can be determined as the oil volume flowing out of the wheel cylinder corresponding to each pressure reducing valve at the current moment. According to the oil flow and time through each pressure reducing valve, the equivalent volume of the oil flow through each pressure reducing valve can be determined Then the equivalent volume of the oil flow through each pressure reducing valve is used as the outflow volume of the wheel cylinder corresponding to each pressure reducing valve at the current moment.

[0248] The above-mentioned wheel cylinder pressure determination method obtains the current wheel cylinder pressure of each wheel cylinder, the pressure of each accumulator in the controller, and the opening area of each pressure reducing valve. Based on the current wheel cylinder pressure, the pressure of each accumulator in the controller, and the opening area of each pressure reducing valve, the oil flow rate through each pressure reducing valve is determined. The equivalent volume of the oil flow through each pressure reducing valve is then determined as the current oil outflow volume of each wheel cylinder. This method determines the current oil outflow volume of each pressure reducing valve corresponding to the wheel cylinder, and can further determine the volume change of the wheel cylinder. This method enables the determination of wheel cylinder pressure without the use of wheel cylinder pressure sensors, thus reducing costs.

[0249] In one embodiment, Figure 14 As shown, the oil volume of each wheel cylinder at the next moment is determined based on the oil volume flowing into and out of each wheel cylinder at the current moment and the oil volume of each wheel cylinder at the previous moment, including:

[0250] S1401, obtaining the oil volume of the accumulator at the previous moment.

[0251] After the oil volume of the accumulator is obtained, the oil volume of the accumulator is stored in a database. Therefore, the oil volume of the accumulator at the previous moment can be obtained from the database.

[0252] S1402: If the oil volume of the accumulator at the previous moment is less than the maximum oil volume threshold of the accumulator, the oil volume of each wheel cylinder at the next moment is determined based on the oil volume flowing into and out of each wheel cylinder at the current moment and the oil volume of each wheel cylinder at the previous moment.

[0253] If the oil volume of the accumulator at the previous moment is less than the maximum oil volume threshold of the accumulator, the oil volume of each wheel cylinder at the next moment can be calculated according to formula (23).

[0254]

[0255] in, represents the wheel cylinder pressure of wheel cylinder i at time k+1, represents the wheel cylinder pressure of wheel cylinder i at time k, represents the volume of oil flowing into wheel cylinder i at time k, represents the outflow volume of the wheel cylinder i at time k, represents the oil volume of the accumulator at time k, V a_max Indicates the maximum oil volume threshold of the accumulator.

[0256] Therefore, when the oil volume of the accumulator at the previous moment is less than the maximum oil volume threshold of the accumulator, the oil volume flowing into and out of each wheel cylinder at the current moment and the oil volume of each wheel cylinder at the previous moment are substituted into formula (23) to obtain the oil volume of each wheel cylinder at the next moment.

[0257] S1403: If the oil volume of the accumulator at the previous moment is greater than or equal to the maximum oil volume threshold of the accumulator, the oil flow rate flowing out of the accumulator at the current moment is obtained, and the oil volume of each wheel cylinder at the next moment is determined based on the oil volume flowing into each wheel cylinder, the oil volume flowing out of the accumulator, the flow rate flowing out of the accumulator, and the oil volume of each wheel cylinder at the previous moment.

[0258] During the passive decompression process, excessive oil flow out of the wheel cylinder may cause the accumulator volume V a May reach the maximum value V a_max At this time, the wheel cylinder and accumulator will become a whole, and the update of the wheel cylinder and accumulator needs to take this into account, that is, the accumulator pressure will suddenly change to the wheel cylinder pressure.

[0259] Therefore, if the oil volume of the accumulator at the previous moment is greater than or equal to the maximum oil volume of the accumulator, the oil volume of each wheel cylinder at the next moment can be calculated according to formula (24).

[0260]

[0261] in, represents the wheel cylinder pressure of wheel cylinder i at time k+1, represents the wheel cylinder pressure of wheel cylinder i at time k, represents the volume of oil flowing into wheel cylinder i at time k, represents the outflow volume of the wheel cylinder i at time k, represents the flow rate out of the accumulator at time k, Δt represents the time interval between the next moment and the previous moment, represents the oil volume of the accumulator at time k, V a_max Indicates the maximum oil volume threshold of the accumulator.

[0262] Among them, how to obtain the flow rate flowing out of the accumulator at the current moment can be described through an embodiment. In one embodiment, as Figure 15 As shown in the figure, the oil flow rate flowing out of the accumulator at the current moment is obtained, including:

[0263] S1501, obtaining the average oil flow of the plunger pump, the oil flow through the suction valve, and the oil volume of the accumulator at the current moment.

[0264] Optionally, the method for obtaining the average oil flow of the plunger pump at the current moment is the same as the method for obtaining the average oil flow of the plunger pump at the current moment in the above embodiment, which will not be repeated here; the method for obtaining the oil flow through the suction valve at the current moment is the same as the method for obtaining the oil flow through the suction valve at the current moment in the above embodiment, which will not be repeated here; the oil volume of the accumulator at the current moment can be obtained from a pre-stored database.

[0265] S1502: Determine the oil flow rate flowing out of the accumulator at the current moment based on the average oil flow rate of the plunger pump, the oil flow rate passing through the suction valve, and the oil volume of the accumulator at the current moment.

[0266] Calculate the oil flow rate flowing out of the accumulator at the current moment according to formula (25).

[0267]

[0268] in, represents the oil flow rate flowing out of the accumulator at time k, represents the average oil flow of the plunger pump at time k, represents the oil volume of the accumulator at time k, Indicates the oil flow rate passing through the suction valve at the current moment.

[0269] The above-mentioned wheel cylinder pressure determination method obtains the accumulator oil volume at the previous moment. If the accumulator oil volume at the previous moment is less than the accumulator's maximum oil volume threshold, the oil volume of each wheel cylinder at the next moment is determined based on the current oil volume flowing in and out of each wheel cylinder, and the oil volume of each wheel cylinder at the previous moment. If the accumulator oil volume at the previous moment is greater than or equal to the accumulator's maximum oil volume threshold, the oil flow rate flowing out of the accumulator at the current moment is obtained, and the oil volume of each wheel cylinder at the next moment is determined based on the current oil volume flowing in and out of each wheel cylinder, the flow rate flowing out of the accumulator, and the oil volume of each wheel cylinder at the previous moment. In this method, by comparing the accumulator oil volume with the accumulator's maximum oil volume threshold, the oil volume of each wheel cylinder at the next moment can be accurately determined, further ensuring the accuracy of the determined wheel cylinder pressure of each wheel cylinder.

[0270] In one embodiment, the accumulator in the controller is a spring accumulator, so the oil volume and pressure of the accumulator can be updated according to formula (26) and formula (27), that is, the oil volume and pressure of the accumulator at the next moment are determined.

[0271]

[0272]

[0273] in, represents the oil volume of the accumulator at time k+1, represents the oil volume of the accumulator at time k, represents the oil flow through the pressure reducing valve at time k, represents the oil flow rate out of the accumulator at time k, V a_max Indicates the maximum oil volume threshold of the accumulator, represents the pressure of the accumulator at time k+1, F a0 Indicates preload force, A a is the accumulator piston area; K a is the accumulator spring stiffness; is the average wheel cylinder pressure.

[0274] Currently, wheel cylinder pressure is primarily acquired through wheel cylinder pressure sensors. However, these sensors can be damaged by external factors, and installing additional sensors is expensive. Therefore, it is essential to implement redundancy in wheel cylinder sensors through software, or even eliminate them to save costs. Currently, research on wheel cylinder pressure estimation primarily falls into two categories: cause-based methods, which estimate wheel cylinder pressure based on mathematical models of the hydraulic system, and result-based methods, which estimate wheel cylinder pressure based on the vehicle's dynamic state. However, result-based methods cannot provide accurate results under vehicle instability conditions.

[0275] Based on this, one embodiment proposes a wheel cylinder pressure determination method based on a hydraulic control unit (HCU) model. Because it is completely based on the HCU's mathematical model, it has wide applicability and low cost. The wheel cylinder pressure determination algorithm uses solenoid valve and motor control commands within the HCU as input, continuously iteratively updates the hydraulic status of each component, and ultimately outputs an estimated wheel cylinder pressure. This process primarily includes: updating the valve spool and motor status, performing data preprocessing; updating the flow and pressure status of each component before the pump; updating the flow and pressure status of each component after the pump; and updating the flow and pressure status of each component after the wheel.

[0276] In one embodiment, taking the controller as a hydraulic control unit as an example, the embodiment includes the following steps:

[0277] a. Calculate the motor speed, displacement, and opening area of the solenoid valve core based on the input duty cycle of the DC motor and solenoid valve;

[0278] Among them, the solenoid valve includes a suction valve, a pressure reducing valve, a pressure limiting valve and a pressure boosting valve.

[0279] b. Calculate the average oil flow rate of the plunger pump based on the motor speed.

[0280] c. Determine the oil flow rate through the suction valve based on the current accumulator pressure, master cylinder pressure, and the opening area of the suction valve;

[0281] Specifically, the pressure difference at both ends of the suction valve is determined based on the accumulator pressure and the master cylinder pressure at the current moment, as well as the fixed negative pressure generated by the plunger pump when working, and the oil flow rate through the suction valve is determined based on the pressure difference at both ends of the suction valve at the current moment and the opening area of the suction valve.

[0282] d. Determine the outflow oil flow from the plunger pump and the accumulator at the current moment based on the average oil flow of the plunger pump, the oil flow through the suction valve, and the oil volume of the accumulator at the current moment.

[0283] e. Obtaining the working mode of the hydraulic control unit and determining the oil flow rate passing through each boost valve at the current moment according to the working mode of the hydraulic control unit;

[0284] ① In the passive boost state (master cylinder pressure is greater than wheel cylinder pressure, and all components in the HCU are de-energized), the current oil flow rate through each boost valve is determined based on the current pump pressure, wheel cylinder pressure, and boost valve opening area.

[0285] ② In the passive decompression state (the master cylinder pressure is greater than the wheel cylinder pressure, the pressure reducing valve and the plunger pump are energized, the master cylinder pressure drops rapidly, and the excess oil is pumped out by the motor pump), the oil flow through each boost valve is 0 at the current moment;

[0286] ③ In the active boost state (master cylinder pressure is less than wheel cylinder pressure, and the boost valve, suction valve, pressure limiting valve, and plunger pump are energized), if only one wheel cylinder is boosting, the current oil flow rate through the pressure limiting valve is calculated based on the pump outlet pressure, master cylinder pressure, and the opening area of the pressure limiting valve;

[0287] Determine the oil flow rate entering the pump at the current moment based on the oil flow rate passing through the pressure limiting valve and the average oil flow rate of the plunger pump at the current moment;

[0288] If only one wheel cylinder requires a boost, the flow rate after the pump is determined to be the oil flow rate passing through the boost valve that requires a boost at the current moment, and the oil flow rate through the boost valve that does not require a boost is 0;

[0289] If two wheel cylinders need to be pressurized, the total wheel cylinder oil volume at the current moment is determined based on the oil volume of each wheel cylinder at the current moment, and then the pump back pressure at the current moment is determined based on the characteristic curve of the volume-pressure change relationship. The total wheel cylinder oil volume at the next moment is determined based on the oil flow entering the pump at the current moment and the total wheel cylinder oil volume at the current moment; the pump back pressure at the next moment is determined based on the total wheel cylinder oil volume at the next moment, and the oil volume of each wheel cylinder at the next moment is determined based on the characteristic curve of the volume-pressure change relationship. The oil flow flowing into each wheel cylinder at the current moment is calculated based on the oil volume of each wheel cylinder at the next moment and the current moment.

[0290] ④ In the active decompression state (the master cylinder pressure is less than the wheel cylinder pressure, and the pressure limiting valve is energized);

[0291] If only one wheel cylinder requires pressure reduction, the oil flow rate after the pump is determined based on the oil flow through the pressure-limiting valve. At this time, the oil flow rate after the pump is the oil flow rate of the booster valve that requires pressure reduction, and the oil flow rate of the booster valve that does not require pressure reduction is 0.

[0292] If both wheel cylinders are depressurized, the total wheel cylinder oil volume at the current moment is determined based on the oil volume of each wheel cylinder at the current moment, and then the pump back pressure at the current moment is determined based on the characteristic curve of the volume-pressure change relationship. The total wheel cylinder oil volume at the next moment is determined based on the oil flow rate flowing out of the pump at the current moment and the total wheel cylinder oil volume at the current moment; the pump back pressure at the next moment is determined based on the total wheel cylinder oil volume at the next moment, and the oil volume of each wheel cylinder at the next moment is determined based on the characteristic curve of the volume-pressure change relationship. The oil flow rate flowing into each wheel cylinder at the current moment is calculated based on the oil volume of each wheel cylinder at the next moment and the current moment.

[0293] f. Determine the current oil flow rate through the pressure reducing valve based on the current wheel cylinder pressure, accumulator pressure, and opening area of the pressure reducing valve.

[0294] g. Determine the oil volume of each wheel cylinder at the next moment based on the relationship between the oil volume of the accumulator at the current moment and the maximum oil volume threshold;

[0295] If the current accumulator oil volume is less than the maximum oil volume threshold, the oil volume of each wheel cylinder at the next moment is determined based on the current oil volume of each wheel cylinder, the oil flow through each boost valve, and the oil flow through each pressure reducing valve.

[0296] Otherwise, the oil volume of each wheel cylinder at the next moment is determined based on the oil volume of each wheel cylinder at the current moment, the oil flow through each boost valve, the oil flow through each pressure reducing valve, and the oil flow out of the accumulator.

[0297] h, and determine the wheel cylinder pressure of each wheel cylinder at the next moment based on the oil volume of each wheel cylinder at the next moment and the characteristic curve of the volume-pressure change relationship.

[0298] In addition, the pressure and oil volume of the accumulator can also be updated; the oil volume of the accumulator at the next moment is determined based on the pressure of the accumulator at the current moment, the oil flow through the pressure reducing valve and the oil flow out of the accumulator; the pressure of the accumulator at the next moment is determined based on the relationship between the oil volume of the accumulator at the next moment and the maximum oil volume threshold; if the oil volume of the accumulator at the next moment is less than the maximum oil volume threshold, the pressure of the accumulator at the next moment is calculated based on the oil volume of the accumulator at the next moment; otherwise, the average value of the wheel cylinder pressure at the current moment is determined as the accumulator pressure at the next moment.

[0299] The specific definition of the wheel cylinder pressure determination method provided in this embodiment can be found in the step definitions of each embodiment of the wheel cylinder pressure determination method described above, and will not be repeated here.

[0300] It should be understood that, although each step in the attached flow chart in the above-described embodiment is shown in sequence according to the indication of the arrow, these steps are not necessarily performed in sequence according to the order indicated by the arrow. Unless clearly stated herein, the execution of these steps does not have strict order restrictions, and these steps can be performed in other orders. Moreover, at least a portion of the steps in the attached figure in the above-described embodiment may include multiple steps or multiple stages, and these steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of the steps or stages in other steps or other steps.

[0301] In one embodiment, the present application further provides a wheel cylinder pressure determination device, which includes: an acquisition module, an update module, and a determination module, wherein:

[0302] an acquisition module, configured to acquire the current volume of oil flowing into the wheel cylinder corresponding to each boosting valve based on the current oil flow rate passing through each boosting valve in the controller; and to acquire the current volume of oil flowing out of each wheel cylinder based on the current oil flow rate passing through the pressure reducing valve corresponding to each boosting valve in the controller;

[0303] An updating module, configured to determine the oil volume of each wheel cylinder at a next moment based on the oil volume flowing into and out of each wheel cylinder at a current moment and the oil volume of each wheel cylinder at a previous moment;

[0304] The determination module is used to determine the wheel cylinder pressure of each wheel cylinder at the next moment based on a preset volume-pressure change relationship and the oil volume of each wheel cylinder at the next moment.

[0305] In one embodiment, the acquisition module includes:

[0306] A first acquiring unit, configured to acquire the operating mode of the controller at a current moment;

[0307] a first determining unit, configured to determine the oil flow rate passing through each boost valve at a current moment according to an operating mode of the controller;

[0308] The second determining unit is configured to determine the equivalent volume of the oil flow passing through each boosting valve as the volume of oil flowing into the wheel cylinder corresponding to each boosting valve at a current moment.

[0309] In one embodiment, the first determining unit includes:

[0310] a first determining subunit for determining, if the controller is in a passive boosting mode, the oil flow rate passing through each boosting valve at a current moment based on the wheel cylinder pressure of each wheel cylinder, the pump outlet pressure, and the opening area of each boosting valve at a current moment; the pump outlet pressure representing the pressure of the boosting valve and the pressure limiting valve;

[0311] The second determining subunit is configured to determine that the oil flow rate passing through each boost valve at a current moment is 0 if the operating mode of the controller is the passive pressure reducing mode.

[0312] In one embodiment, the first determining unit includes:

[0313] a third determining subunit, for determining, for any main line, an oil flow rate passing through the pressure-limiting valve at a current moment based on the pump outlet pressure, the master cylinder pressure, and the opening area of the pressure-limiting valve at a current moment if the operating mode of the controller is the active boost mode;

[0314] a fourth determining subunit, configured to obtain the oil flow rate flowing out of the plunger pump at a current moment, and determine the oil flow rate entering the main line after the pump at a current moment based on the oil flow rate passing through the pressure limiting valve and the oil flow rate flowing out of the plunger pump at a current moment;

[0315] a fifth determining subunit, configured to determine the wheel cylinder that needs to be pressurized at the current moment based on the wheel cylinder pressure of each wheel cylinder at the previous moment and a preset target pressure;

[0316] The sixth determining subunit is configured to determine the oil flow rate passing through each pressure boosting valve at a current moment according to the oil flow rate after the pump entering the main line at a current moment and the number of wheel cylinders requiring pressure boosting.

[0317] In one embodiment, the sixth determining subunit includes:

[0318] a first determining subunit configured to, if the number of wheel cylinders requiring boosting is one, determine the oil flow rate after the pump entering the main line at a current moment as the oil flow rate passing through the boost valve corresponding to the wheel cylinder requiring boosting at a current moment;

[0319] The second judgment subunit is used to determine the oil flow rate passing through each boost valve at the current moment based on the oil volume of each wheel cylinder at the previous moment and the oil flow rate after the pump enters the main line at the current moment if the number of wheel cylinders requiring boost is two.

[0320] In one embodiment, the first determining unit includes:

[0321] a seventh determining subunit, for determining, for any main line, the oil flow rate flowing out of the pump of the main line at the current moment based on the oil flow rate passing through the pressure limiting valve at the current moment, if the operating mode of the controller is the active pressure reducing mode;

[0322] an eighth determining subunit, configured to determine the wheel cylinder requiring decompression at a current moment based on the wheel cylinder pressures of the wheel cylinders at a previous moment and a preset target pressure;

[0323] The ninth determining subunit is configured to determine the oil flow rate passing through each pressure boosting valve at a current moment according to the oil flow rate flowing out of the main line after the pump and the number of wheel cylinders requiring decompression.

[0324] In one embodiment, the ninth determining subunit includes:

[0325] a third determining subunit, configured to, if the number of the wheel cylinder requiring decompression is one, determine the oil flow rate flowing out of the pump of the main line at the current moment as the flow rate passing through the boost valve corresponding to the wheel cylinder requiring decompression at the current moment;

[0326] The fourth judgment subunit is used to determine the oil flow rate passing through each boost valve at the current moment based on the oil volume of each wheel cylinder at the previous moment and the oil flow rate after the pump flows out of the main line at the current moment if the number of wheel cylinders requiring decompression is two.

[0327] In one embodiment, the acquisition module includes:

[0328] a first acquiring unit, configured to acquire the wheel cylinder pressure of each wheel cylinder, the pressure of each accumulator in the controller, and the opening area of each pressure reducing valve at a current moment;

[0329] a third determining unit, configured to determine an oil flow rate passing through each pressure reducing valve according to a current wheel cylinder pressure of each wheel cylinder, a pressure of each accumulator in the controller, and an opening area of each pressure reducing valve;

[0330] The fourth determining unit is configured to determine the equivalent volume of the oil flow passing through each pressure reducing valve as the oil outflow volume of each wheel cylinder at a current moment.

[0331] In one embodiment, the update module includes:

[0332] The second acquisition unit is used to obtain the oil volume of the accumulator at the previous moment;

[0333] a first updating unit configured to determine, if the oil volume of the accumulator at a previous moment is less than a maximum oil volume threshold of the accumulator, the oil volume of each wheel cylinder at a next moment based on the oil volume flowing into and out of each wheel cylinder at a current moment and the oil volume of each wheel cylinder at a previous moment;

[0334] The second updating unit is configured to obtain the oil flow rate flowing out of the accumulator at a current moment if the oil volume of the accumulator at a previous moment is greater than or equal to a maximum oil volume threshold of the accumulator, and determine the oil volume of each wheel cylinder at a next moment based on the oil volume flowing into each wheel cylinder, the oil volume flowing out of the accumulator, the flow rate flowing out of the accumulator, and the oil volume of each wheel cylinder at a previous moment.

[0335] In one embodiment, the second updating unit includes:

[0336] The acquisition subunit is used to obtain the average oil flow of the plunger pump, the oil flow through the suction valve and the oil volume of the accumulator at the current moment;

[0337] The updating subunit is used to determine the oil flow rate flowing out of the accumulator at the current moment according to the average oil flow rate of the plunger pump at the current moment, the oil flow rate passing through the suction valve and the oil volume of the accumulator.

[0338] The specific definitions of the wheel cylinder pressure determination device can be found in the definitions of the various steps in the wheel cylinder pressure determination method described above and will not be repeated here. Each module in the aforementioned wheel cylinder pressure determination device may be implemented in whole or in part via software, hardware, or a combination thereof. Each module may be embedded in or independent of the target device in hardware form, or stored in memory within the target device in software form, allowing the target device to call and execute the corresponding operations of each module.

[0339] In one embodiment, a computer device is provided, such as Figure 16As shown, the computer device includes a processor, a memory, a communication interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for determining wheel cylinder pressure is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a key, trackball or touchpad provided on the computer device housing, or an external keyboard, touchpad or mouse.

[0340] Those skilled in the art will understand that Figure 16 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0341] In one embodiment, a computer device is further provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps in the above method embodiments when executing the computer program.

[0342] The implementation principles and technical effects of each step implemented by the processor in this embodiment are similar to those of the above-mentioned wheel cylinder pressure determination method and will not be repeated here.

[0343] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0344] The implementation principles and technical effects of the steps implemented when the computer program in this embodiment is executed by the processor are similar to those of the above-mentioned wheel cylinder pressure determination method and will not be repeated here.

[0345] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0346] The implementation principles and technical effects of the steps implemented when the computer program in this embodiment is executed by the processor are similar to those of the above-mentioned wheel cylinder pressure determination method and will not be repeated here.

[0347] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0348] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processor involved in the various embodiments provided herein may be, but are not limited to, a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, and the like.

[0349] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0350] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for determining wheel cylinder pressure, characterized in that: The method comprises: Obtaining the current volume of oil flowing into the wheel cylinder corresponding to each boosting valve based on the current oil flow rate passing through each boosting valve in the controller; and obtaining the current volume of oil flowing out of each wheel cylinder based on the current oil flow rate passing through the pressure reducing valve corresponding to each boosting valve in the controller; determining the oil volume of each wheel cylinder at a next moment based on the oil volume flowing into and out of each wheel cylinder at a current moment and the oil volume of each wheel cylinder at a previous moment; determining the wheel cylinder pressure of each wheel cylinder at a next moment based on a preset volume-pressure change relationship and the oil volume of each wheel cylinder at a next moment; The step of determining the oil volume of each wheel cylinder at a next moment based on the oil volume flowing into and out of each wheel cylinder at a current moment and the oil volume of each wheel cylinder at a previous moment includes: Get the oil volume of the accumulator at the last moment; If the oil volume of the accumulator at the previous moment is less than the maximum oil volume threshold of the accumulator, determining the oil volume of each wheel cylinder at the next moment based on the oil volume flowing into and out of each wheel cylinder at the current moment and the oil volume of each wheel cylinder at the previous moment; If the oil volume of the accumulator at the previous moment is greater than or equal to the maximum oil volume threshold of the accumulator, the oil flow rate flowing out of the accumulator at the current moment is obtained, and the oil volume of each wheel cylinder at the next moment is determined based on the inflow oil volume, outflow oil volume, flow rate flowing out of the accumulator, and the oil volume of each wheel cylinder at the previous moment.

2. The method according to claim 1, characterized in that The step of obtaining the volume of oil flowing into the wheel cylinder corresponding to each boosting valve at the current moment based on the oil flow rate passing through each boosting valve in the controller at the current moment includes: Get the working mode of the controller at the current moment; determining the oil flow rate passing through each of the boost valves at a current moment according to the operating mode of the controller; The equivalent volume of the oil flow passing through each of the boosting valves is determined as the volume of oil flowing into the wheel cylinder corresponding to each of the boosting valves at the current moment.

3. The method according to claim 2, characterized in that Determining the oil flow rate passing through each of the boost valves at a current moment according to the working mode of the controller includes: If the operating mode of the controller is the passive boosting mode, the oil flow rate passing through each of the boosting valves at the current moment is determined based on the wheel cylinder pressure of each wheel cylinder, the pump outlet pressure, and the opening area of each of the boosting valves at the current moment; the pump outlet pressure represents the pressure of the boosting valve and the pressure limiting valve; If the working mode of the controller is the passive pressure reducing mode, it is determined that the oil flow passing through each of the boosting valves at the current moment is 0.

4. The method according to claim 2, characterized in that The controller includes two symmetrical main lines, one of which includes two wheel cylinders. The method of determining the oil flow rate passing through each of the boost valves at a current moment according to the operating mode of the controller includes: For any main line, if the operating mode of the controller is the active boost mode, the oil flow rate passing through the pressure limiting valve at the current moment is determined based on the current pump outlet pressure, the master cylinder pressure, and the opening area of the pressure limiting valve; Obtaining the oil flow rate flowing out of the plunger pump at the current moment, and determining the oil flow rate entering the pump of the main line at the current moment based on the oil flow rate passing through the pressure limiting valve and the oil flow rate flowing out of the plunger pump at the current moment; determining the wheel cylinder that needs to be pressurized at the current moment based on the wheel cylinder pressure of each wheel cylinder at the previous moment and a preset target pressure; The oil flow rate passing through each of the boosting valves at the current moment is determined according to the oil flow rate after entering the main line after the pump and the number of wheel cylinders that require boosting.

5. The method according to claim 4, characterized in that The determining of the oil flow rate passing through each of the boost valves at the current moment based on the oil flow rate after the pump entering the main line at the current moment and the number of wheel cylinders requiring boosting includes: If the number of wheel cylinders requiring pressure boost is one, the oil flow rate after the pump entering the main line at the current moment is determined as the oil flow rate passing through the pressure boost valve corresponding to the wheel cylinder requiring pressure boost at the current moment; If there are two wheel cylinders that require pressurization, the oil flow rate passing through each of the boost valves at the current moment is determined based on the oil volume of each wheel cylinder at the previous moment and the oil flow rate after the pump entering the main line at the current moment.

6. The method according to claim 2, characterized in that The controller includes two symmetrical main lines, one of which includes two wheel cylinders. The method of determining the oil flow rate passing through each of the boost valves at a current moment according to the operating mode of the controller includes: For any main line, if the operating mode of the controller is the active pressure reduction mode, the oil flow rate flowing out of the pump of the main line at the current moment is determined based on the oil flow rate passing through the pressure limiting valve at the current moment; determining the wheel cylinder that needs to be decompressed at the current moment based on the wheel cylinder pressure of each wheel cylinder at the previous moment and a preset target pressure; The current oil flow rate passing through each of the pressure-increasing valves is determined according to the current oil flow rate flowing out of the pump of the main line and the number of wheel cylinders requiring reduced pressure.

7. The method according to claim 6, characterized in that The determining of the oil flow rate passing through each of the boost valves at the current moment based on the oil flow rate flowing out of the pump of the main line at the current moment and the number of wheel cylinders requiring decompression includes: If the number of the wheel cylinder requiring decompression is one, the flow rate of the oil flowing out of the pump of the main line at the current moment is determined as the flow rate passing through the boost valve corresponding to the wheel cylinder requiring decompression at the current moment; If there are two wheel cylinders requiring decompression, the oil flow rate passing through each of the boost valves at the current moment is determined based on the oil volume of each wheel cylinder at the previous moment and the oil flow rate flowing out of the pump of the main line at the current moment.

8. The method according to any one of claims 1 to 7, characterized in that The step of obtaining the outflow volume of the oil from each wheel cylinder at the current moment according to the oil flow rate passing through the pressure reducing valve corresponding to each pressure increasing valve in the controller at the current moment includes: obtaining the wheel cylinder pressure of each wheel cylinder, the pressure of each accumulator in the controller, and the opening area of each pressure reducing valve at a current moment; determining an oil flow rate passing through each of the pressure reducing valves according to a current wheel cylinder pressure of each wheel cylinder, a pressure of each accumulator in the controller, and an opening area of each pressure reducing valve; The equivalent volume of the oil flow passing through each of the pressure reducing valves is determined as the outflow volume of the oil from each of the wheel cylinders at the current moment.

9. The method according to claim 4, characterized in that The obtaining of the oil flow rate flowing out of the accumulator at the current moment includes: Obtaining the average oil flow rate of the plunger pump, the oil flow rate through the suction valve, and the oil volume of the accumulator at the current moment; The oil flow rate flowing out of the accumulator at the current moment is determined according to the average oil flow rate of the plunger pump at the current moment, the oil flow rate passing through the suction valve, and the oil volume of the accumulator.

Images