Optimization design method for brake-by-wire linear electromagnetic valve

Abstract

The invention belongs to the technical field of brake-by-wire linear electromagnetic valves, and relates to an optimal design method for a brake-by-wire linear electromagnetic valve. Comprising the steps that according to an obtained valve element opening degree model, sealing performance and pressure maintaining capacity evaluation indexes are established, and mechanical performance, consistency and controllability are quantitatively described according to constraints, the sensitivity of hydraulic pressure to structural parameters, the sensitivity of electromagnetic force to electromagnetic parameters, the sensitivity of pressure to current, a pressure fluctuation evaluation index and a minimum regulation and control pressure index; calculating the sensitivity direction of the parameter, qualitatively analyzing the influence rule of the parameter on the performance, and pre-classifying to obtain an initial parameter; according to performance requirements, initial parameters are selected, a comprehensive index is established, and optimal solution calculation is carried out by utilizing the comprehensive index and constraints so as to obtain optimal design parameters of the linear electromagnetic valve; according to the method, better consistency and controllability are achieved while it is guaranteed that the mechanical performance meets the requirement.

Description

Technical Field

[0001] This invention belongs to the field of linear solenoid valve technology, specifically relating to an optimized design method for a linear solenoid valve with line control braking. Background Technology

[0002] Linear normally open valves are among the most commonly used solenoid valves in brake-by-wire systems (such as Onebox) or brake stability systems (ABS, ESC). Their typical structure is as follows: Figure 1As shown, during operation, the lower end is the oil inlet (high-pressure oil), and the side is the oil outlet (low-pressure oil). When the coil is energized, an electromagnetic force is generated between the moving iron 9 and the stationary iron 1, causing the moving iron 9 to move downwards, leading to the valve core 6 tending to close. Different coil currents will generate different electromagnetic forces. The "linearity" of the linear normally open valve is reflected in the fact that, within the linear range of the solenoid valve, as the current increases linearly, the steady-state pressure difference between the oil inlet and outlet of the solenoid valve increases linearly. At the same time, when the pressure difference is constant, the rate of pressure change at the outlet also decreases linearly. Obviously, if the solenoid valve has linear characteristics, when used in a braking system, the pressure or rate of pressure change at the outlet of the solenoid valve can be controlled by controlling the current of the coil. This will greatly improve the control accuracy and response speed of the wheel braking pressure, and improve the performance of the braking system (especially functions related to pressure control, such as ABS, AYC, deceleration control, etc.). It is particularly important to note that since braking systems are software-controlled, if the aforementioned current-pressure difference relationship and current-pressure change rate relationship are not perfectly linear, the relevant curves can be obtained through pre-testing, and then linearity can be achieved through software compensation, as mentioned in the specification of patent CN118935069A. Therefore, for linear solenoid valves, the most critical performance characteristics are: ① Consistency of performance between different solenoid valves with unified design parameters (hereinafter referred to as consistency). That is, different solenoid valves may have inconsistent hydraulic and electromagnetic characteristics due to mechanical tolerances. The design of solenoid valves should ensure that the performance of solenoid valves is as consistent as possible under the same tolerance conditions. This is the only way to achieve linear compensation of solenoid valves through pre-testing methods and the same software; ② Controllability of solenoid valves (hereinafter referred to as controllability). That is, the characteristics of solenoid valves with the same control current should not change too much. If the change is too large, the braking pressure will change drastically with slight adjustments to the current. This requires extremely high current accuracy to control the pressure precisely, which makes the electrical system design very difficult. At the same time, the response of the same solenoid valve should not fluctuate repeatedly under the same control current. ③ It is required to ensure the basic mechanical performance of the solenoid valve, such as maximum sealing pressure and leakage rate.In existing publicly available technical documents, there is no description of a linear valve design method (especially a parameter design method after the structure is determined) that meets the above-mentioned performance requirements of solenoid valves. For example, patent CN118935069A describes a testing method, patent CN108799600A introduces a structure for realizing the function of a linear valve, patent CN103192815B introduces a pressure control method under the condition that the structure is determined, and patent CN103115185A introduces a structure of a linear valve that meets special process requirements. Patent CN119538633A proposes a solenoid valve optimization algorithm based on global optimization. However, linear solenoid valves have many parameters. If all parameters are optimized without distinction, the optimization computation will be extremely large and the optimization difficulty will be extremely high. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide an optimized design method for a linear solenoid valve with line control.

[0004] To achieve the objectives of this invention, the following technical solutions are adopted.

[0005] An optimization design method for a linear solenoid valve with in-line braking includes the following steps:

[0006] S1. Based on the electromagnetic-hydraulic model, overflow state differential pressure model, and flow coefficient of the linear solenoid valve, the valve core opening model of the linear solenoid valve is obtained through the geometric relationship of the linear solenoid valve.

[0007] S2. By establishing sealing performance evaluation index and pressure holding capacity evaluation index to describe mechanical performance, as well as constraints, the mechanical performance index of the linear solenoid valve is quantitatively described.

[0008] S3. By establishing the sensitivity of hydraulic pressure to structural parameters and the sensitivity of electromagnetic force to electromagnetic parameters, the consistency of linear solenoid valves is quantitatively described.

[0009] S4. By establishing evaluation indices for pressure sensitivity to current, pressure fluctuation, and minimum control pressure, the controllability of linear solenoid valves is quantitatively described.

[0010] S5. Calculate the sensitivity direction of the main design parameters based on the index established in steps S2, S3 and S4, qualitatively analyze the influence of the main design parameters on the performance of the linear solenoid valve, and pre-classify the linear solenoid valves to obtain the initial parameters of each type of linear solenoid valve.

[0011] S6. Based on the performance requirements of the linear solenoid valve, select different initial parameters, establish a comprehensive index describing the function, consistency and controllability of the linear solenoid valve, and use the comprehensive index and constraints to calculate the optimal solution to obtain the optimized design parameters of the linear solenoid valve.

[0012] Preferably, the electromagnetic-hydraulic model is expressed by equation (1):

[0013]

[0014] In the formula: A a1 A aw A a3 A a4 Let A be the area region, where: region a1 is the sealing region when the valve core contacts the valve seat, representing the force-bearing region of the valve core under static pressure sealing; region aw is the annular region near the contact line between the valve core and the valve seat, where the pressure rapidly decreases and transitions to the same level as the outlet pressure; region a2 is the outlet region; region a3 is the annular region at the bottom of the valve core excluding a1 and aw; region a4 is the top region of the valve core; the flow rate, area, velocity, force, and pressure in the above regions are represented by Q, A, v, F, and P, respectively; the throttling point at the flow channel formed by the valve core and valve seat is denoted as aj, and the throttling area and flow rate at this point are denoted as Aaj and Qaj, respectively; C d Let θa1 and θaj be the hydraulic flow coefficients, and let θa1 and θaj be the angles between the liquid flow direction at the inlet and outlet and the valve core movement direction, respectively.

[0015] Preferably, the overflow state pressure difference model is expressed by equation (2):

[0016]

[0017] In the formula: K a1 F is the flow coefficient. h The hydraulic pressure is approximately equal to F. f That is, F h =F f .

[0018] Preferably, the flow coefficient K a1 Expressed by equation (3):

[0019]

[0020] In the formula: ρ is the fluid density, and ζ is the energy dissipation coefficient.

[0021] Preferably, the valve core opening model is expressed by equation (4):

[0022]

[0023] In the formula: d bLet θ be the diameter of the valve core ball head. aj The angle of the valve seat cone surface.

[0024] Preferably, the sealing performance evaluation index is the sealing line length J. v1 Its expression is:

[0025] J v1 =πd b cosθ aj (5)

[0026] In the formula: d b Let θ be the diameter of the valve core ball head. aj The angle of the valve seat cone surface.

[0027] Preferably, the pressure holding capacity evaluation index J v2 The reciprocal of the pressure holding capacity is expressed as:

[0028]

[0029] In the formula: F mag and F s It consists of the electromagnetic force of the solenoid valve and the spring force acting on the valve core, A a1 It is the sealing area of ​​a static seal.

[0030] Preferably, the constraint restricts the linear solenoid valve to remain normally open during reverse flow, which can be expressed as:

[0031] limit v1 :F s >F fmax (7)

[0032] In the formula: F s For the spring force, F fmax This represents the maximum hydraulic pressure during reverse flow.

[0033] Preferably, the sensitivity J of the hydraulic pressure to the structural parameters is... v3 Expressed using a cost function:

[0034]

[0035] In the formula: q v31 and q v32 F represents the weights of hydraulic pressure on the sensitivity of the valve seat cone angle and the ball head diameter, respectively. f The hydraulic pressure is represented by equation (1).

[0036] Preferably, the electromagnetic force is sensitive to electromagnetic parameters J. v4 The expression is:

[0037]

[0038] In the formula: F mag The electromagnetic force curve is obtained from the experiment, and δ represents the electromagnetic air gap.

[0039] Preferably, the sensitivity evaluation index of pressure to current is the resolution of pressure regulation, described as:

[0040]

[0041] Where: ΔP v5 Let ΔI be the pressure change. v5 This represents the change in current.

[0042] Preferably, the pressure fluctuation evaluation index J v6 The expression is:

[0043] J v6 =|P y1 -P y2 |,I=I y (15)

[0044] In the formula: P y1 and P y2 They are respectively the control current I y Pressure in both closed and overflow states.

[0045] Preferably, the minimum control pressure index J v7 Expressed using a cost function that minimizes regulatory pressure:

[0046] J v7 =|P y1 -P y2 |,I=I close (16)

[0047] In the formula: P y1 and P y2 They are respectively the control current I close Pressure in both closed and overflow states.

[0048] Preferably, the expression for the comprehensive index J is:

[0049] J = q1J v1 +q2J v2 +q3J v3 +q4J v4 +q5J v5 +q6J v6 +q7J v7 (17)

[0050] In the formula: q1 to q7 are the weights of the seven cost functions, and different values ​​are selected according to their importance.

[0051] Preferably, the optimal solution is calculated using a particle swarm optimization algorithm, including the following steps:

[0052] S121, Give X j Assign initial values, where: X j ={δ 0,j ,θ aj,j ,F s0,j ,d b,j}, where δ 0，j ,θ aj,j ,F s0,j ,d b,j This indicates the constant air gap, valve seat cone angle, spring preload, and ball head diameter contained in the particle;

[0053] S122. Update the particle state and particle velocity using formulas (18) and (19);

[0054] S123. Repeat step S152 until the stopping condition of the particle swarm optimization algorithm is met. When the particle swarm optimization algorithm stops, use the state plan obtained from the fully optimal particle state to optimize the state, so as to optimize the design parameters of the linear solenoid valve.

[0055] in:

[0056] Formula (18) is:

[0057]

[0058] In the formula: P i The local optimum particle, i.e., the particle that minimizes J during this fitness function calculation, is G. i The particle is the globally optimal particle, that is, the particle that minimizes J in each fitness function calculation. The subscript i indicates the i-th iteration. rand() is used to generate random numbers between [0,1].

[0059] Formula (19) is:

[0060] X i+1 =X i +V i+1 (19)

[0061] The stopping condition is expressed as: (|J i -J i-1 |<ΔJ)||(N>N0)(20), where: ΔJ is the minimum change in two iterations, indicating that the update of the particles has little impact on the fitness function, and N0 is the upper limit of the number of iterations.

[0062] Beneficial effects

[0063] This invention enables valves produced in the same batch according to theoretical specifications to exhibit more similar performance without altering control precision, and to reduce control error under the same control method and manufacturing precision.

[0064] This invention increases the linear range of the duty cycle, while simultaneously reducing pressure changes and pressure fluctuations under the same current variation; at the same time, the minimum controllable pressure is also reduced, thus achieving fine pressure control.

[0065] This invention achieves better consistency and controllability while ensuring that the mechanical properties meet the requirements. Attached Figure Description

[0066] Figure 1 This is a typical structural diagram of a linear solenoid valve;

[0067] Figure 2 This is a structural diagram of a linear normally open solenoid valve;

[0068] Figure 3 A framework diagram of the particle swarm optimization algorithm;

[0069] Figure 4 A comparison chart of the pressure-duty cycle curves before and after optimization;

[0070] Figure 5 A comparison chart of the pressure-duty cycle curves of the same batch of solenoid valves before and after optimization. Detailed Implementation

[0071] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0072] In order to design a linear normally open solenoid valve that meets the above-mentioned consistency, sensitivity, and mechanical performance, this invention proposes a parameter optimization design method for solenoid valves. By converting performance indicators into a quantifiable cost function, the cost function is optimized and solved to obtain the optimal design target of the solenoid valve.

[0073] (1) Electromagnetic-hydraulic model of linear normally open valve.

[0074] A structural diagram of a normally open valve, as shown below. Figure 2 As shown, the hydraulic force F of the solenoid valve f It can be expressed by equation (1):

[0075]

[0076] In the formula: A a1 A aw A a3 Aa4 for Figure 2 The area regions shown are as follows: Region a1 is the sealing region where the valve core contacts the valve seat, representing the stress region of the valve core under static pressure sealing; Region aw is the annular region near the contact line between the valve core and the valve seat, where the pressure rapidly decreases and transitions to the same level as the outlet pressure; Region a2 is the outlet region; Region a3 is the annular region at the bottom of the valve core excluding a1 and aw; Region a4 is the top region of the valve core. The flow rate, area, velocity, force, and pressure in these regions are represented by Q, A, v, F, and P, respectively. Furthermore, the throttling point at the flow path formed by the valve core and valve seat is denoted as aj, and the throttling area and flow rate here are denoted as Aaj and Qaj, respectively; C d Let θa1 and θaj be the hydraulic flow coefficients, and let θa1 and θaj be the angles between the liquid flow direction at the inlet and outlet and the valve core movement direction, respectively.

[0077] The differential pressure model for the solenoid valve overflow state is expressed by equation (2):

[0078]

[0079] In the formula: K a1 F is the flow coefficient. h The hydraulic pressure is approximately equal to F. f That is, F h =F f Wherein: Flow coefficient K a1 Expressed by equation (3):

[0080]

[0081] In the formula: ρ is the fluid density, and ζ is the energy dissipation coefficient.

[0082] The valve core opening model is expressed by equation (4) based on the geometric relationship of the solenoid valve:

[0083]

[0084] In the formula: d b The diameter of the ball head of the valve core.

[0085] (2) Quantitative description method of mechanical performance index of linear valve;

[0086] Step 1: Establish evaluation index J to describe the sealing performance of mechanical properties v1Analysis revealed that the sealing performance is mainly related to the line seal length. The longer the seal length, the more likely there are leakage points due to manufacturing deviations along the entire seal line. The more or larger the leakage points, the worse the sealing performance of the solenoid valve. In addition, the longer the seal line, the lower the contact stress at the seal, and the less the valve core or valve seat can compensate for the leakage points by straining. Therefore, the length of the seal line composed of the spherical surface of the valve core and the conical surface of the valve seat is used for evaluation. The length of the seal line is expressed by equation (5):

[0087] J v1 =πd b cosθ aj (5)

[0088] In the formula: d b Let θ be the diameter of the valve core ball head. aj The angle of the valve seat cone surface.

[0089] Step 2: Establish evaluation indicators to describe the mechanical performance of buck teeth J v2 The pressure holding capacity of a solenoid valve refers to the maximum pressure that the solenoid valve can seal under a certain voltage input. It is proposed to use the reciprocal of the maximum sealing pressure for evaluation, expressed by equation (6):

[0090]

[0091] In the formula: F mag and F s It consists of the electromagnetic force of the solenoid valve and the spring force acting on the valve core, A a1 It is the sealing area of ​​the static seal. According to equation (1), in order to improve the pressure holding capacity of the solenoid valve, the electromagnetic force should be increased, the spring force should be reduced, or the sealing area should be reduced. In terms of the design parameters of the solenoid valve, the constant air gap should be reduced, the valve seat cone angle should be increased, the spring preload should be reduced, or the ball head diameter should be reduced.

[0092] Step 3: Establish constraints describing mechanical performance, namely, the solenoid valve remains open during reverse flow. Analysis shows that requiring the solenoid valve to remain open during reverse flow means that the valve core should not close when the brake fluid flows from the outlet to the inlet under a certain pressure difference. This restriction is expressed in the form of constraint (7):

[0093] limit v1 :F s >F fmax (7)

[0094] In the formula: F s For the spring force, F fmax This represents the maximum hydraulic pressure during reverse flow.

[0095] (3) Quantitative description method of linear valve consistency.

[0096] The consistency of a linear valve refers to the sensitivity of the solenoid valve to manufacturing parameters. It requires the consistency between the input current and the pressure difference across the solenoid valve under linear control conditions. Under solenoid valve control, the electromagnetic force and hydraulic pressure acting on the valve core are balanced. The electromagnetic force is related to the input current, and the hydraulic pressure is related to the pressure difference. Therefore, reducing the sensitivity of the electromagnetic force to electromagnetic parameters and reducing the sensitivity of the hydraulic pressure to structural parameters can improve the consistency of the linear valve. Therefore, the following method is used to establish a consistency evaluation index.

[0097] Step 1: Establish the sensitivity of hydraulic pressure to manufacturing parameters, which is expressed by equation (8):

[0098]

[0099] In the formula: q v31 and q v32 F represents the weights of hydraulic pressure on the sensitivity of the valve seat cone angle and the ball head diameter, respectively. f The hydraulic pressure is expressed by equation (1). Considering that the hydraulic pressure generated by the pressure difference is the main part in equation (8), therefore, F is... f Simplified to equation (9), from equations (8) and (9), we can obtain the cost function expression of equation (10), where: equation (9) is:

[0100]

[0101] In the formula: P a1 This is due to import pressure.

[0102] Equation (10) is:

[0103]

[0104] According to equation (10), in order to reduce sensitivity, the valve seat cone angle should be made as far away from 45° as possible, and the diameter of the ball head should be reduced.

[0105] Step 2: Establish the sensitivity of electromagnetic force to manufacturing parameters, which can be expressed as J v4 Format:

[0106]

[0107] In the formula: F mag The electromagnetic force curve is obtained from the experiment, and δ represents the electromagnetic air gap.

[0108] (4) Quantitative description method of linear valve controllability

[0109] Step 1: Establish a sensitivity evaluation index J for pressure to electric current. v5The sensitivity of pressure to current is called the resolution of pressure control. A smaller value indicates a smaller pressure change for the same current change, and thus, more precise pressure control for the same control current resolution. This value, J... v5 Described as:

[0110]

[0111] Where: ΔP v5 Let ΔI be the pressure change. v5 This represents the change in current.

[0112] Step 2: Establish an evaluation index for pressure fluctuation. Pressure fluctuation refers to the magnitude of pressure fluctuation when the pressure regulating valve is in overflow mode. Specifically, this condition can be described as follows: under a certain control current, when a certain flow rate is input to the inlet of the pressure regulating valve, the solenoid valve core should theoretically be suspended at its equilibrium position. However, the presence of flow or pressure disturbances will cause the solenoid valve to repeatedly open and close. This repeated opening and closing will cause pressure fluctuations at the inlet of the solenoid valve. When there are external pressure fluctuations, the smaller this index, the better the suppression of pressure fluctuations.

[0113] The magnitude of pressure fluctuation is mainly determined by the maximum sealing pressure P that the solenoid valve can withstand when closed. y0 The equilibrium pressure P in the suspended state y1 The difference between the two is the pressure fluctuation.

[0114] When the valve core is in the closed state, the valve core displacement is 0. At this time, the maximum sealing pressure is the ratio of the maximum electromagnetic force to the sealing area. The maximum sealing pressure can be obtained by solving equation (13), where: Equation (13) is:

[0115]

[0116] In the formula: F h For hydraulic pressure, A a1 Where δ is the sealing area, δ is the actual air gap, δ0 is the theoretical air gap, and F mag F represents the electromagnetic force, f(·) is the electromagnetic force curve, and F s denoted as , where is the spring force and x is the actual displacement of the valve core.

[0117] When the valve core is in the overflow state, the displacement of the valve core is related to the valve opening degree, calculated according to equation (4). The pressure difference across the solenoid valve is calculated according to equation (2). The pressure during overflow is calculated by equation (14):

[0118]

[0119] In the formula: Q1 is the flow rate, K a1 C is the flow coefficient. d This is the hydraulic flow coefficient.

[0120] The pressure fluctuation of the solenoid valve can be described by the control current I. y The pressure difference between the closed state and the overflow state:

[0121] J v6 =|P y1 -P y2 |,I=I y (15)

[0122] In the formula: P y1 and P y2 They are respectively the control current I y Pressure in both closed and overflow states.

[0123] Step 3: Establish the minimum control pressure index. This phenomenon refers to the situation where the control current is just the right current I to put the solenoid valve in the overflow state. close At the same time, continuously increasing the current will not increase the pressure, but when the current continues to rise to a certain value, the pressure will suddenly change. This sudden pressure change is the minimum control pressure. When the target pressure is less than the minimum control pressure, it cannot be achieved by controlling the current. The reason for the occurrence of the minimum control pressure is the same as the reason for the occurrence of pressure fluctuations. The only difference is that the current I is the current at which the solenoid valve just opens. close The cost function for minimizing regulatory pressure:

[0124] J v7 =|P y1 -P y2 |,I=I close (16)

[0125] In the formula: P y1 and P y2 Solve by referring to equations (13) and (14), P y1 and P y2 They are respectively the control current I close Pressure in both closed and overflow states.

[0126] (5) Solenoid valve pre-classification method

[0127] Step 1: Establish sensitivity direction. J... v1 To J v7The indicators were differentiated with respect to the main design parameters (mainly: constant air gap, valve seat cone angle, spring preload, and ball head diameter) to obtain the sensitivity of different indicators to the design parameters. The direction of change of the design parameters and the indicators was analyzed, resulting in Table 1. In Table 1, "↑" and "↓" indicate the requirements for the performance or parameter, while "-" indicates an unknown state or minimal impact. Taking the sealing requirement as an example, which is one of the functional requirements of a linear valve, the sealing performance needs to be as good as possible. This requires the sealing line length between the ball head and the valve seat to be as small as possible, which corresponds to either the valve seat cone angle being as large as possible or the ball head cone angle being as small as possible. The results in the table show that the functional requirements, consistency requirements, and controllability requirements all place different demands on the structural parameters of the solenoid valve. It is impossible to find a set of parameters that simultaneously satisfies all three to achieve the optimal state. Therefore, the optimization design problem of the linear valve is transformed into a multi-objective optimization problem of parameters.

[0128] Step 2: Set different classification groups to obtain rough parameters for 6 types of solenoid valves. Directly optimizing all possible values ​​of all design parameters would result in an extremely large computational load and a high risk of getting trapped in local optima, leading to solutions that are not globally optimal and affecting solenoid valve performance. Therefore, a method of pre-classifying solenoid valves based on sensitivity direction is proposed. The main steps are: first, find the direction of parameter influence on different performance characteristics. For example, a decrease in the fixed air gap leads to an increase in mechanical performance (functional requirements) but a decrease in consistency and controllability. Based on this method, all parameters can be analyzed. Second, select different combinations of solenoid valve performance. For example, if the importance of performance requirements is mechanical performance > controllability > consistency, then for the highest mechanical performance requirement, the fixed air gap should be reduced, the valve seat cone angle increased, the spring and pressure reduced, and the ball head diameter reduced. For the second highest controllability requirement, the fixed air gap, valve seat cone angle, and ball head diameter can be appropriately increased (all increases should be less than the changes caused by mechanical performance). Based on this method, preliminary parameters X for this type of solenoid valve can be given. j ={δ 0,j ,θ aj,j ,F s0,j ,d b,j Similarly, the other five types of solenoid valves can be analyzed to obtain preliminary parameters.

[0129] (6) Method for refining and optimizing linear valve parameters

[0130] Step 1: Select different initial optimization parameters X based on the performance requirements of the solenoid valve. j ={δ 0,j ,θ aj,j ,F s0,j ,d b,j}

[0131] Step 2: Establish a comprehensive index J describing the function, consistency, and controllability of the solenoid valve. The comprehensive index J is expressed as:

[0132] J = q1J v1 +q2J v2 +q3J v3 +q4J v4 +q5J v5 +q6J v6 +q7J v7 (17)

[0133] In the formula: q1 to q7 are the weights of the seven cost functions, and different values ​​can be selected according to their importance.

[0134] Step 3: Set the optimization parameters as follows, where δ 0，j ,θ aj,j ,F s0,j ,d b,j This indicates the constant air gap, valve seat cone angle, spring preload, and ball head diameter contained in the particle:

[0135] X j ={δ 0,j ,θ aj,j ,F s0,j ,d b,j}

[0136] Step 4: Perform optimization calculations according to the cost function expressed by equation (17) and the constraints expressed by equation (7). One feasible approach is to use the particle swarm optimization algorithm.

[0137] First, give X j Assign initial values.

[0138] Second, update the particle state and particle velocity according to equations (18) and (19):

[0139]

[0140] X i+1 =X i +V i+1 (19)

[0141] In the formula: P i The local optimum particle, i.e., the particle that minimizes J during this fitness function calculation, is G. i The particle is the globally optimal particle, that is, the particle that minimizes J in each fitness function calculation. The subscript i indicates the i-th iteration. rand() is used to generate random numbers between [0,1].

[0142] Third, repeat step two until the stopping condition of the optimization algorithm is:

[0143] (|J i -J i-1 |<ΔJ)||(N>N0) (20)

[0144] In the formula: ΔJ is the minimum change between two iterations, indicating that the particle update has little impact on the fitness function; N0 is the upper limit of the number of iterations. When the particle swarm optimization algorithm stops, the obtained G... i The state obtained from the state planning optimization corresponds to the optimization result of the linear valve, such as... Figure 3 As shown.

[0145] Table 1

[0146]

[0147] The pressure-duty cycle curves before and after optimization are as follows: Figure 4 and Figure 5 As shown, since the current cannot be actually controlled in the braking system, the current is indirectly controlled by the voltage duty cycle. It can be assumed that the duty cycle and the current are directly proportional. It can be seen that after optimization, the pressure fluctuation of the solenoid valve is reduced, the minimum controllable pressure is reduced, and the linear range of the duty cycle is increased.

[0148] The preferred embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of the claims of the present application. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and substance of the embodiments of the present application shall be within the scope of the claims of the present application.

Claims

1. A method for optimizing the design of a linear solenoid valve with line-controlled braking, characterized in that: Includes the following steps: S1. Based on the electromagnetic-hydraulic model, overflow state differential pressure model, and flow coefficient of the linear solenoid valve, the valve core opening model of the linear solenoid valve is obtained through the geometric relationship of the linear solenoid valve. S2. By establishing sealing performance evaluation index and pressure holding capacity evaluation index to describe mechanical performance, as well as constraints, the mechanical performance index of the linear solenoid valve is quantitatively described. S3. By establishing the sensitivity of hydraulic pressure to structural parameters and the sensitivity of electromagnetic force to electromagnetic parameters, the consistency of linear solenoid valves is quantitatively described. S4. By establishing evaluation indices for pressure sensitivity to current, pressure fluctuation, and minimum control pressure, the controllability of linear solenoid valves is quantitatively described. S5. Calculate the sensitivity direction of the main design parameters based on the index established in steps S2, S3 and S4. Perform a pre-classification of the linear solenoid valves by qualitatively analyzing the influence of the main design parameters on the performance of the linear solenoid valves, so as to obtain the initial parameters of each type of linear solenoid valve. S6. Based on the performance requirements of the linear solenoid valve, select different initial parameters, establish a comprehensive index describing the function, consistency and controllability of the linear solenoid valve, and use the comprehensive index and constraints to calculate the optimal solution to obtain the optimized design parameters of the linear solenoid valve.

2. The method for optimizing the design of a linear solenoid valve with line control according to claim 1, characterized in that: The valve core opening model is expressed by equation (4): In the formula: d b Let θ be the diameter of the valve core ball head. aj The angle of the valve seat cone surface.

3. The method for optimizing the design of a linear solenoid valve with line control according to claim 1, characterized in that: The sealing performance evaluation index is the sealing line length J. v1 Its expression is: J v1 =πd b cosθ aj (5) In the formula: d b Let θ be the diameter of the valve core ball head. aj The angle of the valve seat cone surface.

4. The optimized design method for a linear solenoid valve with line control according to claim 1, characterized in that: The pressure holding capacity evaluation index J v2 The reciprocal of the pressure holding capacity is expressed as: In the formula: F mag and F s It consists of the electromagnetic force of the solenoid valve and the spring force acting on the valve core, A a1 It is the sealing area of ​​a static seal.

5. The optimized design method for a linear solenoid valve with line control according to claim 1, characterized in that: The constraint requires that the linear solenoid valve remain normally open during reverse flow, which can be expressed as: limit v1 :F s >F fmax (7) In the formula: F s For the spring force, F fmax This represents the maximum hydraulic pressure during reverse flow.

6. The optimized design method for a linear solenoid valve with line control according to claim 1, characterized in that: The sensitivity of the hydraulic pressure to structural parameters J v3 Expressed using a cost function: In the formula: q v31 and q v32 F represents the weights of hydraulic pressure on the sensitivity of the valve seat cone angle and the ball head diameter, respectively. f The hydraulic pressure is represented by equation (1).

7. The optimized design method for a linear solenoid valve with line control according to claim 1, characterized in that: The sensitivity J of the electromagnetic force to electromagnetic parameters v4 The expression is: In the formula: F mag The electromagnetic force curve is obtained from the experiment, and δ represents the electromagnetic air gap.

8. The optimized design method for a linear solenoid valve with line control according to claim 1, characterized in that: The sensitivity evaluation index of pressure to current is the resolution of pressure regulation, described as follows: Where: ΔP v5 Let ΔI be the pressure change. v5 This represents the change in current.

9. The optimized design method for a linear solenoid valve with line control according to claim 1, characterized in that: The pressure fluctuation evaluation index J v6 The expression is: J v6 =|P y1 -P y2 |,I=I y ; (15) In the formula: P y1 and P y2 They are respectively the control current I y Pressure in both closed and overflow states.

10. The optimized design method for a linear solenoid valve with line control according to claim 1, characterized in that: The minimum control pressure index J v7 Expressed using a cost function that minimizes regulatory pressure: J v7 =|P y1 -P y2 |,I=I close ; (16) In the formula: P y1 and P y2 They are respectively the control current I close Pressure in both closed and overflow states.

11. The optimized design method for a linear solenoid valve with line control according to claim 1, characterized in that: The expression for the comprehensive index J is: J=q1J v1 +q2J v2 +q3J v3 +q4J v4 +q5J v5 +q6J v6 +q7J v7 ; (17) In the formula: q1 to q7 are the weights of the seven cost functions, and different values ​​are selected according to their importance.

12. The method for optimizing the design of a linear solenoid valve with line control according to claim 1, characterized in that: The optimal solution is calculated using the particle swarm optimization algorithm, and includes the following steps: S121, Give X j Assign initial values, where: X j ={δ 0,j ,θ aj,j ,F s0,j ,d b,j }, where δ 0，j ,θ aj,j ,F s0,j ,d b,j This indicates the constant air gap, valve seat cone angle, spring preload, and ball head diameter contained in the particle; S122. Update the particle state and particle velocity using formulas (18) and (19); S123. Repeat step S152 until the stopping condition of the particle swarm optimization algorithm is met. When the particle swarm optimization algorithm stops, use the state plan obtained from the fully optimal particle state to optimize the state, so as to optimize the design parameters of the linear solenoid valve. in: Formula (18) is: In the formula: P i The local optimum particle, i.e., the particle that minimizes J during this fitness function calculation, is G. i The particle is the globally optimal particle, that is, the particle that minimizes J in each fitness function calculation. The subscript i indicates the i-th iteration. rand() is used to generate random numbers between [0,1]. Formula (19) is: X i+1 =X i +V i+1 ; (19) The stopping condition is expressed as: (|J i -J i-1 |<ΔJ)||(N>N0)(20), where: ΔJ is the minimum change in two iterations, indicating that the update of the particles has little impact on the fitness function, and N0 is the upper limit of the number of iterations.

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