Pressure estimation method for on-off valve model and heterogeneous multi-source brake system

Abstract

The application provides a pressure estimation method of a switch valve model, a control module compatible with a heterogeneous multi-source braking system, a braking module and the heterogeneous multi-source braking system, comprising a control strategy module, an intermediate layer and a braking actuator, wherein the intermediate layer is arranged between the control strategy module and the braking actuator; the intermediate layer converts a control instruction into an instruction suitable for different braking actuators, and converts different bottom-layer feedbacks into the same upper-layer feedback; the control strategy module sends an upper-layer instruction to the intermediate layer, the intermediate layer sends a bottom-layer instruction to the braking actuator according to the upper-layer instruction, the braking actuator sends a bottom-layer feedback to the intermediate layer, and the intermediate layer sends an upper-layer feedback to the control strategy layer according to the bottom-layer feedback; and the technical scheme can realize the construction of vehicles with different requirements through the free combination of different shafts.

Description

Technical Field

[0001] This invention relates to the field of vehicle braking technology, and in particular to a pressure estimation method for a switching valve model, a control module compatible with heterogeneous multi-source braking systems, a braking module, and a heterogeneous multi-source braking system. Background Technology

[0002] Due to cost considerations, technological changes, and heterogeneous redundancy requirements, different braking systems may be equipped on the same car model. For example, for cost reasons, the lower-cost System A usually has slightly worse control performance and is therefore equipped on lower-spec models, while higher-spec models of the same car are equipped with a more expensive System B. During technological changes, due to performance upgrades, shortages of braking systems, or other reasons, a car may switch from System A to System B, or vice versa. Regarding heterogeneous redundancy requirements, considering that some high-safety vehicles (such as autonomous vehicles and military vehicles) require that the braking systems of all wheels not fail simultaneously, using braking systems with different technological approaches can effectively prevent simultaneous failures due to the same cause (such as design problems, batch manufacturing problems, or identical installation methods). This feature is also known as heterogeneous redundancy. When a braking system is modified, not only the mechanical and electronic hardware but also the software must be changed. However, different braking system hardware configurations typically require different software. Traditional methods necessitate developing separate software for each hardware component on the same chassis, resulting in a massive development workload and extremely high costs. Furthermore, hardware changes require separate software development, which is time-consuming, especially in cases of unforeseen circumstances (such as stock shortages). This can impact vehicle development timelines or even halt production or delivery, leading to significant downtime and breach of contract costs. To address these potential problems, developing a unified control method for different braking systems, requiring only minor adaptive modifications when the braking system changes, will effectively solve these issues. Moreover, different braking systems using a unified control method can easily be combined to form braking systems with heterogeneous characteristics.

[0003] Patent CN118306360B proposes a braking system based on a combination of redundant brake pressure regulating valves and automatic pressure regulating valves. This system cannot precisely control the wheel pressure; therefore, a logic threshold method is typically used to indirectly control the wheel braking pressure (when certain logic conditions are met by the vehicle or wheel at full capacity, the valve performs pressure boosting, pressure reduction, or pressure holding operations). (Reference) Figure 1Similar to this system, the front axle (first axle) braking system of WABCO's widely used EBS system, marked at position 1M, indirectly controls wheel braking pressure through two ABS valves connected to the 1M axle module. Another typical braking system configuration is the rear axle of WABCO's EBS system, marked at position 2M. The 2M axle module contains two electronically controllable output pressure modules, each connected to one of the two wheels. These modules can independently control the output pressure; therefore, during braking system control, the software directly calculates the required braking pressure for each wheel, which is then executed by the braking system.

[0004] For different chassis configurations, commonly used technical solutions include: Figure 2 As shown, if the chassis is an on / off valve, the control strategy provides on / off commands (pressurization / pressure reduction / pressure holding). However, if the chassis is a pressure servo system, the control command is the target pressure, and the pressure servo system feeds back the actual pressure to the control strategy. This architecture results in strategies C and D not being interchangeable.

[0005] In traditional methods, one feasible approach that technicians can think of is to estimate the braking pressure (such as patent application CN113688584A). This can reduce the software development workload or improve the software's adaptability to different hardware systems through self-learning. Such methods can usually solve the problem of different performance of the same type of braking system on the same car due to manufacturing differences. However, if we want to apply the same algorithm to different braking systems (not just differences in manufacturing parameters), we need to completely innovate the braking control method. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a pressure estimation method for a switching valve model, a control module compatible with a heterogeneous multi-source braking system, a braking module, and a heterogeneous multi-source braking system, so as to realize the construction of vehicles with different requirements by freely combining different axles.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a pressure estimation method for a switching valve model, comprising the following steps:

[0008] Step 1: Convert the valve voltage command into a valve core opening / closing command. Since the electrical signal needs to undergo a mechanical response delay before the valve core opens, this delay time is used here. To describe, At the current time, the states of the intake valve and exhaust valve in the switching valve system are calculated using formula (1) as follows: and ;

[0009] (1); where, The state of the valve core is represented by 1 (open) and 0 (closed). U is the control input voltage. When U is high, the valve core is open; otherwise, the valve core is closed.

[0010] Step 2: Calculate the diaphragm cavity pressure based on the valve core state; when the valve core is open, the gas mass flow rate through the orifice is expressed as equation (2), where equation (2) Let be the gas flow rate. This is the gas unloading coefficient. It is the area of ​​the flow orifice. For the pressure at the input port, Let be the ideal gas constant. The absolute gas temperature The expression is shown in (3), where in equation (3) The air insulation coefficient, The pressure at the output port;

[0011] (2)

[0012] (3);

[0013] Given the gas flow rate, calculate the total mass of gas in the cavity by integration according to equation (4). In equation (4) and It is the gas mass at the current moment and the previous moment. The time interval between the two calculations;

[0014] (4);

[0015] Then, the pressure of the diaphragm cavity is calculated according to equation (5). In the formula, For the volume of the diaphragm cavity, is the molar mass constant of the gaseous medium;

[0016] (5);

[0017] Step 3: Calculate the diaphragm state based on the diaphragm cavity pressure. ;

[0018] Step 4: Based on the state of the diaphragm, calculate the mass of gas flowing into or out of the wheel cylinder through the large hole of the diaphragm cavity, and then calculate the braking pressure.

[0019] In a preferred embodiment, step 4 specifically includes: in step 3, the membrane state is calculated as shown in equation (6), where... , These are the areas of the large and small surfaces of the diaphragm, respectively, where the pressure acts. , , It is the gas pressure in the corresponding area. The preload of the diaphragm spring;

[0020] (6).

[0021] In a preferred embodiment, step 4 specifically includes: first calculating the mass flow rate, for the intake flow rate... When the intake diaphragm is open, it is calculated according to formula (2); when the intake diaphragm is closed, it is recorded as 0; for exhaust flow rate When the exhaust diaphragm is open, the calculation is performed according to formula (2); when the exhaust diaphragm is closed, the result is recorded as 0. Therefore, the total flow rate into the wheel cylinder is... Secondly, calculate the total mass of gas in the cylinder according to formula (4), where... Take as the total flow rate into the wheel cylinder Finally, calculate the wheel cylinder pressure according to formula (5), where... This refers to the total volume of the cavity from the ABS valve outlet to the wheel cylinder.

[0022] The present invention also provides a control module compatible with heterogeneous multi-source braking systems, including a control strategy module, an intermediate layer and a braking actuator. The intermediate layer is disposed between the control strategy module and the braking actuator. The intermediate layer converts control commands into commands adapted to different braking actuators, and converts different lower-level feedbacks into the same upper-level feedbacks.

[0023] The control strategy module sends upper-layer instructions to the middle layer, the middle layer sends lower-layer instructions to the brake actuator according to the upper-layer instructions, the brake actuator sends lower-layer feedback to the middle layer, and the middle layer sends upper-layer feedback to the control strategy layer according to the lower-layer feedback.

[0024] The intermediate layer operates a switching valve model, which performs the pressure estimation method for the switching valve model described in any one of claims 1-3.

[0025] In a preferred embodiment, the upper-level command is the valve opening and closing command, and the upper-level feedback is the pressure value. Under this control module, when the brake actuator is a valve opening and closing system, the intermediate layer directly assigns the upper-level command to the lower-level command, the intermediate layer runs the valve opening and closing model, and the intermediate layer estimates the pressure based on the lower-level feedback and then assigns it to the upper-level feedback.

[0026] In this control module, when the brake actuator is a servo system, the intermediate layer predicts the bottom pressure response of the brake system based on the running switch valve model, and sends the pressure response as the target pressure to the bottom layer as an instruction. The actual pressure fed back by the bottom layer is directly assigned to the upper layer feedback.

[0027] In a preferred embodiment, the upper-level command is the target pressure command, and the middle layer runs the switching valve model. Under this control module, when the brake actuator is a switching valve system, the middle layer performs pressure estimation, outputs the lower-level command based on the deviation between the target pressure and the current pressure, and uses the pressure estimation value as feedback to the upper layer.

[0028] In this control module, when the brake actuator is a servo system, the target pressure value is directly used as the lower-level command, and the actual pressure value is used as the upper-level feedback.

[0029] The present invention also provides a braking module, used as a braking actuator in the control module of the aforementioned compatible heterogeneous multi-source braking system; comprising:

[0030] The first air inlet 1 is connected to the air source;

[0031] The first air outlet 21 and the second air outlet 22 are respectively connected to the wheel cylinder;

[0032] The first control air port 4 is connected to the brake foot valve;

[0033] It also includes a first relay valve a1, a first silencer b1, a first normally open valve c1, a first normally closed valve d1, and a first pressure sensor e; it amplifies the small flow rate of gas from the first control port 4 to a large flow rate of gas from the second outlet 22 at a 1:1 input pressure ratio; the second outlet 22 is equipped with the first pressure sensor e, which is used to measure the pressure of the second outlet 22; one end of the first silencer b1 is connected to the vent of the first relay valve a1, and the other end of the first silencer b1... One end is connected to the atmosphere; when the first normally open valve c1 is de-energized, the first relay valve a1 is connected to the second outlet 22, and the gas from the first relay valve a1 flows to the second outlet 22. When the first normally open valve c1 is energized, it closes, cutting off the connection between the first relay valve a1 and the second outlet 22. When the first normally closed valve d1 is de-energized, it cuts off the connection between the second outlet 22 and the atmosphere. When it is energized, the second outlet 22 is connected to the atmosphere, and the gas from the second outlet 22 is unloaded to the atmosphere through the first normally closed valve d1.

[0034] It also includes a second relay valve, a second silencer, a second normally open valve, a second normally closed valve, and a second pressure sensor. The connection relationship between the first air outlet 21 and the second relay valve, the second silencer, the second normally open valve, the second normally closed valve, and the second pressure sensor is the same as the connection relationship between the second air outlet 22 and the first relay valve a1, the first silencer b1, the first normally open valve c1, the first normally closed valve d1, and the first pressure sensor e.

[0035] In a preferred embodiment, when neither the first normally open valve c1 nor the first normally closed valve d1 is energized, the braking module is in a pressurization state. If the pressure at the second outlet 22 is lower than the outlet pressure of the first relay valve a1, the pressure at the second outlet 22 will further increase. When the first normally open valve c1 is energized and the first normally closed valve d1 is not energized, the module is in a pressure-holding state, and the pressure remains constant. When both the first normally open valve c1 and the first normally closed valve d1 are energized, the gas at the second outlet 22 is discharged into the atmosphere, and the module is in a pressure-reducing state. By comparing the pressure measured by the first pressure sensor e with the target pressure, when the actual pressure is too low, the module is controlled to enter a pressurization state; when the error between the actual pressure and the target pressure is less than a preset threshold, the module is controlled to enter a pressure-holding state; and when the actual pressure is too high, the module is controlled to enter a pressure-reducing state, thereby controlling the first outlet 21 and the second outlet 22.

[0036] The present invention also provides a braking module, used as a braking actuator in the control module of the aforementioned compatible heterogeneous multi-source braking system; comprising:

[0037] The second air inlet 5 is connected to the air source;

[0038] The third air outlet 23 and the fourth air outlet 24 are respectively connected to the wheel cylinder;

[0039] The second control air port 6 is connected to the brake foot valve;

[0040] It also includes a third relay valve a2, a third silencer b2, a third pressure sensor c2, and a pressure servo module d2;

[0041] Based on the pressure command given by the control input, the corresponding pressure is output at the inlet of the third relay valve a2.

[0042] The present invention also provides a heterogeneous multi-source braking system, including the control module of the aforementioned compatible heterogeneous multi-source braking system, wherein the combination of the front axle and the rear axle includes: a switching valve system and a switching valve system, a switching valve system and a servo system, a servo system and a switching valve system, and a servo system and a servo system.

[0043] Compared with the prior art, the present invention has the following advantages: it allows shaft modules with different braking system configurations to be freely combined without changing the software design. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the Wabco braking system;

[0045] Figure 2 This is a schematic diagram of a traditional control algorithm architecture;

[0046] Figure 3This is a schematic diagram of the control architecture of a compatible heterogeneous multi-source braking system according to a preferred embodiment of the present invention;

[0047] Figure 4 This is a schematic diagram of the switching valve system architecture according to a preferred embodiment of the present invention;

[0048] Figure 5 This is a schematic diagram of the servo system architecture according to a preferred embodiment of the present invention;

[0049] Figure 6 This is a schematic diagram of the switching valve architecture according to a preferred embodiment of the present invention;

[0050] Figure 7 This is a schematic diagram of a two-axle braking system according to a preferred embodiment of the present invention;

[0051] Figure 8 This is a schematic diagram of a preferred embodiment of the three-axis braking system of the present invention;

[0052] Figure 9 The pressure estimation diagram for a 30ms boost every 200ms is shown in the preferred embodiment of the present invention, where (a) is the wheel cylinder pressure and (b) is the intake diaphragm chamber pressure;

[0053] Figure 10 The pressure estimation diagram for a fully de-energized intake valve according to a preferred embodiment of the present invention is shown, wherein (a) is the wheel cylinder pressure and (b) is the intake diaphragm chamber pressure.

[0054] Figure 11 The pressure estimation graph for a preferred embodiment of the present invention is shown, where the pressure is reduced by 7ms every 30ms. In this graph, (a) is the wheel cylinder pressure and (b) is the exhaust diaphragm chamber pressure.

[0055] Figures 9 to 11 In the middle, P c,s P represents the measured pressure value of the brake wheel cylinder. c,e P represents the estimated pressure value of the brake wheel cylinder. d,s P represents the measured pressure value of the intake diaphragm. d,e This represents the estimated pressure of the intake diaphragm. Detailed Implementation

[0056] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0057] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0058] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application; as used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise; furthermore, it should be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0059] refer to Figure 3-11 A control module compatible with heterogeneous multi-source braking systems includes a control strategy module, an intermediate layer, and a braking actuator. The intermediate layer is located between the control strategy module and the braking actuator. The intermediate layer converts control commands into commands adapted to different braking actuators, and converts different lower-level feedbacks into the same upper-level feedbacks.

[0060] The control strategy module sends upper-layer instructions to the middle layer, the middle layer sends lower-layer instructions to the brake actuator according to the upper-layer instructions, the brake actuator sends lower-layer feedback to the middle layer, and the middle layer sends upper-layer feedback to the control strategy layer according to the lower-layer feedback.

[0061] There are two implementation methods. One implementation method is: the upper-level instruction is the valve opening and closing instruction, and the upper-level feedback is the pressure value. Under this control module, when the brake actuator is a valve opening and closing system, the intermediate layer directly assigns the upper-level instruction to the lower-level instruction. The intermediate layer runs the valve opening and closing model and estimates the pressure based on the lower-level feedback, and then assigns the value to the upper-level feedback.

[0062] In this control module, when the brake actuator is a servo system, the intermediate layer predicts the bottom pressure response of the brake system based on the running switch valve model, and sends the pressure response as the target pressure to the bottom layer as an instruction. The actual pressure fed back by the bottom layer is directly assigned to the upper layer feedback.

[0063] Another implementation method is: the upper layer command is the target pressure command, the middle layer runs the switching valve model. Under this control module, when the brake actuator is a switching valve system, the middle layer performs pressure estimation, outputs the lower layer command based on the deviation between the target pressure and the current pressure, and uses the pressure estimation value as feedback to the upper layer.

[0064] In this control module, when the brake actuator is a servo system, the target pressure value is directly used as the lower-level command, and the actual pressure value is used as the upper-level feedback.

[0065] A hardware architecture for a braking system is proposed, in which each axle is an independent module, including a braking module and brake wheel cylinders, for controlling the pressure of two brake wheel cylinders respectively. It has an independent power supply and is connected to the vehicle's communication network, allowing the software design of this braking system to avoid considering the specific hardware specifications.

[0066] Based on the above braking system architecture, the braking module used as a braking actuator is described below, including:

[0067] The first air inlet 1 is connected to the air source;

[0068] The first air outlet 21 and the second air outlet 22 are respectively connected to the wheel cylinder;

[0069] The first control air port 4 is connected to the brake foot valve;

[0070] It also includes a first relay valve a1, a first silencer b1, a first normally open valve c1, a first normally closed valve d1, and a first pressure sensor e; the small flow rate of gas at the first control port 4 is amplified to a large flow rate of gas at the second outlet 22 at a 1:1 input pressure ratio; the second outlet 22 is equipped with the first pressure sensor e, which is used to measure the pressure at the second outlet 22; one end of the first silencer b1 is connected to the vent of the first relay valve a1, and the other end of the first silencer b1 is open to the atmosphere. When the first normally open valve c1 is de-energized, the first relay valve a1 is connected to the second outlet 22, and the gas from the first relay valve a1 flows to the second outlet 22. When the first normally open valve c1 is energized, it closes, cutting off the connection between the first relay valve a1 and the second outlet 22. When the first normally closed valve d1 is de-energized, it cuts off the connection between the second outlet 22 (through the first silencer b1) and the atmosphere. When it is energized, the second outlet 22 is connected to the atmosphere, and the gas from the second outlet 22 is unloaded to the atmosphere through the first normally closed valve d1. Figure 4 The dense dotted line connects to the ECU and is a control line.

[0071] It also includes a second relay valve, a second silencer, a second normally open valve, a second normally closed valve, and a second pressure sensor. The connection relationship between the first air outlet 21 and the second relay valve, the second silencer, the second normally open valve, the second normally closed valve, and the second pressure sensor is the same as the connection relationship between the second air outlet 22 and the first relay valve a1, the first silencer b1, the first normally open valve c1, the first normally closed valve d1, and the first pressure sensor e.

[0072] When neither the first normally open valve c1 nor the first normally closed valve d1 is energized, the braking module is in a pressurization state. If the pressure at the second outlet 22 is lower than the outlet pressure of the first relay valve a1, the pressure at the second outlet 22 will rise further. When the first normally open valve c1 is energized and the first normally closed valve d1 is not energized, the module is in a pressure-holding state, and the pressure remains constant. When both the first normally open valve c1 and the first normally closed valve d1 are energized, the gas at the second outlet 22 is discharged into the atmosphere, and the module is in a pressure-reducing state. By comparing the pressure measured by the first pressure sensor e with the target pressure, when the actual pressure is too low, the module is controlled to enter a pressurization state. When the error between the actual pressure and the target pressure is less than a preset threshold (e.g., ±0.02MPa), the module is controlled to enter a pressure-holding state. When the actual pressure is too high, the module is controlled to enter a pressure-reducing state, thereby controlling the first outlet 21 and the second outlet 22.

[0073] Based on the above braking system architecture, the following describes another braking module used as a braking actuator, including:

[0074] The second air inlet 5 is connected to the air source;

[0075] The third air outlet 23 and the fourth air outlet 24 are respectively connected to the wheel cylinder;

[0076] The second control air port 6 is connected to the brake foot valve;

[0077] It also includes a third relay valve a2, a third silencer b2, a third pressure sensor c2, and a pressure servo module d2;

[0078] Based on the pressure command given by the control input, the corresponding pressure is output at the inlet of the third relay valve a2.

[0079] exist Figure 4 The key to applying the proposed control architecture to the braking system shown is to establish a model of the switching valve and perform pressure estimation.

[0080] A typical on / off valve (also known as an ABS valve) is as follows: Figure 6As shown in the diagram, I can be connected to a relay valve, II to a wheel cylinder, and III directly to the atmosphere. Taking the working principle of the intake valve as an example, when the coil is not energized, the intake valve core is in the state shown in the diagram under the action of the spring. At this time, the gas in inlet I can push open the intake diaphragm and flow to outlet II. When the coil of the intake valve core is energized, the valve core is attracted and moves downward. The gas in I passes through the intake valve core and then flows to the channel where the double dashed lines are located, and then flows into the diaphragm cavity of the intake valve core. Since the area of ​​the intake valve core diaphragm cavity acting on the upper part of the diaphragm is larger than the area acting on the lower part of the valve core at the outlet, the diaphragm moves downward under the force difference, closing the gas flow channel between I and II. This process includes energization → valve core movement → diaphragm cavity pressure build-up → diaphragm movement → gas flow causing pressure change. To accurately estimate the pressure, a pressure estimation method for the on / off valve model is proposed.

[0081] The pressure estimation method for the on / off valve model includes the following steps:

[0082] Step 1: Convert the valve voltage command into a valve core opening / closing command. Since the electrical signal needs to undergo a mechanical response delay before the valve core opens, this delay time is used here. To describe, At the current time, the states of the intake valve and exhaust valve in the switching valve system are calculated using Formula 1 as follows: and ;

[0083] 1; In the formula, The state of the valve core is represented by 1 (open) and 0 (closed). U is the control input voltage. When U is high, the valve core is open; otherwise, the valve core is closed.

[0084] Step 2: Calculate the diaphragm cavity pressure based on the valve core state; when the valve core is open, the gas mass flow rate through the orifice is expressed as equation (2), where equation (2) Let be the gas flow rate. This is the gas unloading coefficient. It is the area of ​​the flow orifice. For the pressure at the input port, Let be the ideal gas constant. The absolute gas temperature The expression is shown in (3), where in equation (3) The air insulation coefficient, The pressure at the output port;

[0085] (2)

[0086] (3);

[0087] Given the gas mass flow rate, calculate the total gas mass in the current cavity by integration according to Equation 4. In Equation 4... and It is the gas mass at the current moment and the previous moment. The time interval between the two calculations, This represents the gas mass flow rate at the current moment.

[0088] 4;

[0089] Then, the pressure of the diaphragm cavity is calculated according to Equation 5. In the formula, For the volume of the diaphragm cavity, is the molar mass constant of the gaseous medium;

[0090] 5;

[0091] Step 3: Calculate the diaphragm state based on the diaphragm cavity pressure. As shown in Equation 6, in the equation , , These represent the areas of the large surface, small surface, and annular overlapping region where the diaphragm pressure acts, respectively. , , It is the gas pressure in the corresponding area. The preload of the diaphragm spring;

[0092] 6;

[0093] Step 4: Based on the diaphragm's condition, calculate the mass of gas flowing into or out of the wheel cylinder through the large orifice of the diaphragm cavity, and then calculate the braking pressure; first calculate the mass flow rate, for the intake flow rate... When the intake diaphragm is open, it is calculated according to formula (2); when the intake diaphragm is closed, it is recorded as 0; for exhaust flow rate When the exhaust diaphragm is open, the calculation is performed according to formula (2); when the exhaust diaphragm is closed, the result is recorded as 0. Therefore, the total flow rate into the wheel cylinder is... Secondly, calculate the total mass of gas inside the wheel cylinder according to Equation 4, where... Take as the total flow rate into the wheel cylinder Finally, calculate the wheel cylinder pressure according to Equation 5, where... This refers to the total volume of the cavity from the ABS valve outlet to the wheel cylinder.

[0094] Heterogeneous multi-source braking systems, based on the control architecture of the aforementioned braking systems, can be compatible with different modular braking systems. Therefore, different braking systems can be freely combined on a single vehicle, such as... Figure 7As shown in the diagram, E represents the wheel cylinder, G is the main control ECU, H is the air tank, D is the brake foot valve, and F1 and F2 are the same or different brake modules. For example, the front axle + rear axle combination can be: a switch valve system and a switch valve system, a switch valve system and a servo system, a servo system and a switch valve system, or a servo system and a servo system, etc. The advantages of this approach are that different systems can achieve different costs, can be freely combined to address shortages, or using different configurations of braking systems (heterogeneous) can reduce the probability of system failure. Such combinations do not lead to software changes, thus eliminating the need for software redesign and greatly improving the development convenience of the vehicle chassis. Simultaneously, the braking system can be freely selected based on different vehicle characteristics. For example, if a faster front axle response is required, a servo system or an EMB system can be selected to meet different vehicle design requirements. Furthermore, in our patent application CN120056714A, we proposed a vehicle configuration based on axles as the basic unit. This configuration suggests that vehicles with different needs can be constructed through the free combination of different axles. This invention allows axle modules with different braking system configurations to be freely combined without changing the software design. Based on the above ideas, a two-axle braking system can be easily extended to three-axle or more axles, such as... Figure 8 As shown.

Claims

1. A pressure estimation method for a switching valve model, characterized in that, Includes the following steps: Step 1: Convert the valve voltage command into a valve core opening / closing command. Since the electrical signal needs to undergo a mechanical response delay before the valve core opens, this delay time is used here. To describe, At the current time, the states of the intake valve and exhaust valve in the switching valve system are calculated using formula (1) as follows: and ; (1); where, The state of the valve core is represented by 1 (open) and 0 (closed). U is the control input voltage. When U is high, the valve core is open; otherwise, the valve core is closed. Step 2: Calculate the diaphragm cavity pressure based on the valve core state; when the valve core is open, the gas mass flow rate through the orifice is expressed as equation (2), where equation (2) The mass flow rate of the gas. This is the gas unloading coefficient. It is the area of ​​the flow orifice. For the pressure at the input port, Let be the ideal gas constant. The absolute gas temperature The expression is shown in (3), where in equation (3) The air insulation coefficient, The pressure at the output port; （2） （3）； Given the mass flow rate of the gas, calculate the total mass of the gas in the cavity by integral according to equation (4), where equation (4) is... and It is the gas mass at the current moment and the previous moment. The time interval between the two calculations; （4）； Then, the pressure of the diaphragm cavity is calculated according to equation (5). In the formula, For the volume of the diaphragm cavity, is the molar mass constant of the gaseous medium; （5）； Step 3: Calculate the diaphragm state based on the diaphragm cavity pressure. The diaphragm state is calculated as shown in equation (6), where... , These are the areas of the large and small surfaces of the diaphragm, respectively, where the pressure acts. , , It is the gas pressure in the corresponding area. The preload of the diaphragm spring; （6）； Step 4: Based on the state of the diaphragm, calculate the mass of gas flowing into or out of the wheel cylinder through the large hole of the diaphragm cavity, and then calculate the braking pressure.

2. The pressure estimation method for the on / off valve model according to claim 1, characterized in that, Step 4 specifically includes: First, calculating the mass flow rate, for the intake flow rate... When the intake diaphragm is open, it is calculated according to formula (2); when the intake diaphragm is closed, it is recorded as 0; for exhaust flow rate When the exhaust diaphragm is open, the calculation is performed according to formula (2); when the exhaust diaphragm is closed, the result is recorded as 0. Therefore, the total flow rate into the wheel cylinder is... Secondly, calculate the total mass of gas in the cylinder according to formula (4), where... Take as the total flow rate into the wheel cylinder Finally, calculate the wheel cylinder pressure according to formula (5), where... This refers to the total volume of the cavity from the ABS valve outlet to the wheel cylinder.

3. A control module compatible with heterogeneous multi-source braking systems, characterized in that, It includes a control strategy module, an intermediate layer, and a braking actuator. The intermediate layer is located between the control strategy module and the braking actuator. The intermediate layer converts control commands into commands that are adapted to different braking actuators, and converts different lower-level feedbacks into the same upper-level feedbacks. The control strategy module sends upper-layer instructions to the middle layer, the middle layer sends lower-layer instructions to the brake actuator according to the upper-layer instructions, the brake actuator sends lower-layer feedback to the middle layer, and the middle layer sends upper-layer feedback to the control strategy layer according to the lower-layer feedback. The intermediate layer operates a switching valve model, which performs the pressure estimation method for the switching valve model as described in any one of claims 1-2.

4. The control module for a compatible heterogeneous multi-source braking system according to claim 3, characterized in that, The upper-level command is the valve opening and closing command, and the upper-level feedback is the pressure value. Under this control module, when the brake actuator is a valve opening and closing system, the middle layer directly assigns the upper-level command to the lower-level command. The middle layer runs the valve opening and closing model and estimates the pressure based on the lower-level feedback, and then assigns the value to the upper-level feedback. In this control module, when the brake actuator is a servo system, the intermediate layer predicts the bottom pressure response of the brake system based on the running switch valve model, and sends the pressure response as the target pressure to the bottom layer as an instruction. The actual pressure fed back by the bottom layer is directly assigned to the upper layer feedback.

5. The control module for a compatible heterogeneous multi-source braking system according to claim 3, characterized in that, The upper-level command is the target pressure command, and the middle layer runs the switching valve model. Under this control module, when the brake actuator is a switching valve system, the middle layer performs pressure estimation, outputs the lower-level command based on the deviation between the target pressure and the current pressure, and uses the pressure estimation value as feedback to the upper layer. In this control module, when the brake actuator is a servo system, the target pressure value is directly used as the lower-level command, and the actual pressure value is used as the upper-level feedback.

6. A braking module, characterized in that, Used as a brake actuator in the control module of the compatible heterogeneous multi-source braking system as described in claim 4; comprising: The first air inlet (1) is connected to the air source; The first air outlet (21) and the second air outlet (22) are respectively connected to the wheel cylinder; The first control air port (4) is connected to the brake foot valve; It also includes a first relay valve (a1), a first silencer (b1), a first normally open valve (c1), a first normally closed valve (d1), and a first pressure sensor (e); the small flow rate of gas from the first control port (4) is amplified to a large flow rate of gas from the second outlet (22) at a 1:1 input pressure ratio; the second outlet (22) is equipped with a first pressure sensor (e), which is used to measure the pressure of the second outlet (22); one end of the first silencer (b1) is connected to the vent of the first relay valve (a1), and the first silencer (b1) The other end is connected to the atmosphere; when the first normally open valve (c1) is de-energized, the first relay valve (a1) is connected to the second outlet (22), and the gas from the first relay valve (a1) flows to the second outlet (22). When the first normally open valve (c1) is energized, it closes, cutting off the connection between the first relay valve (a1) and the second outlet (22); when the first normally closed valve (d1) is de-energized, it cuts off the connection between the second outlet (22) and the atmosphere. When it is energized, the second outlet (22) is connected to the atmosphere, and the gas from the second outlet (22) is unloaded to the atmosphere through the first normally closed valve (d1); It also includes a second relay valve, a second silencer, a second normally open valve, a second normally closed valve, and a second pressure sensor. The connection relationship between the first air outlet (21) and the second relay valve, the second silencer, the second normally open valve, the second normally closed valve, and the second pressure sensor is the same as the connection relationship between the second air outlet (22) and the first relay valve (a1), the first silencer (b1), the first normally open valve (c1), the first normally closed valve (d1), and the first pressure sensor (e).

7. The braking module according to claim 6, characterized in that, When neither the first normally open valve (c1) nor the first normally closed valve (d1) is energized, the braking module is in a pressurized state. If the pressure at the second outlet (22) is lower than the outlet pressure of the first relay valve (a1), the pressure at the second outlet (22) will rise further. When the first normally open valve (c1) is energized and the first normally closed valve (d1) is not energized, it is in a pressure-holding state, and the pressure will remain unchanged. When the first normally open valve (c1) is energized and the first normally closed valve (d1) is energized, the gas at the second outlet (22) is discharged into the atmosphere, and it is in a pressure-reducing state. By comparing the pressure measured by the first pressure sensor (e) with the target pressure, when the actual pressure is too low, the control enters the pressurized state. When the error between the actual pressure and the target pressure is less than the preset threshold, the control enters the pressure-holding state. When the actual pressure is too high, the control enters the pressure-reducing state. This achieves the control of the first outlet (21) and the second outlet (22).

8. A braking module, characterized in that, Used as a brake actuator in the control module of the compatible heterogeneous multi-source braking system as described in claim 5; comprising: The second air inlet (5) is connected to the air source; The third air outlet (23) and the fourth air outlet (24) are respectively connected to the wheel cylinder; The second control air port (6) is connected to the brake foot valve; It also includes a third relay valve (a2), a third silencer (b2), a third pressure sensor (c2), and a pressure servo module (d2); Based on the pressure command given by the control input, the corresponding pressure is output at the inlet of the third relay valve (a2).

9. A heterogeneous multi-source braking system, characterized in that, The control module of the compatible heterogeneous multi-source braking system as described in claim 4 or 5, wherein the combination of the front axle and the rear axle includes: a switching valve system and a switching valve system, a switching valve system and a servo system, a servo system and a switching valve system, and a servo system and a servo system.

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