Easily-detachable intelligent control proportional electromagnetic valve for breathing machine

Abstract

The invention provides an easily-detachable intelligent control proportional electromagnetic valve for a breathing machine. The proportional electromagnetic valve comprises a valve seat assembly, an armature assembly, a valve sleeve assembly, an adjusting assembly, a coil assembly and a shell assembly. According to the proportional electromagnetic valve, the valve sleeve is made of the magnetism isolating material, the magnetism isolating effect is achieved, and therefore the magnetic flux in the armature is increased; the guide sleeve with an inclined notch structure is arranged, thermal expansion installation is not needed, and maintenance is convenient; in addition, the shell assembly of the proportional electromagnetic valve is designed to be directly installed on the air inlet and outlet tool through bolts, and the proportional electromagnetic valve is easy to assemble and disassemble. Meanwhile, the invention further provides a precise control method for subdivided flow of each stage aiming at different characteristics by adopting a PID closed-loop control mode, so that the linearity of a flow curve of a gas medium supplied by the breathing machine is optimized.

Description

Technical Field

[0001] The present invention relates to the field of precise control of medical devices, and specifically provides an intelligent control proportional solenoid valve device with high flow, quick response, small structure, simple and easy disassembly, and stable electromagnetic force and accurate proportional distribution. Background Art

[0002] A ventilator is essentially a ventilation machine that replaces, controls or changes a person's normal physiological breathing, increases lung ventilation, improves respiratory function, and reduces respiratory function consumption. As an effective means of artificially replacing spontaneous ventilation function, ventilators have been widely used in the following three major areas:

[0003] (1) Respiratory failure caused by respiratory diseases: such as chronic obstructive pulmonary disease, lung infection, and asthma;

[0004] (2) Surgery: including respiratory management during anesthesia for major surgeries, ventilatory support during and after pediatric surgery, etc.; and

[0005] (3) Sleep apnea: such as snoring and sleep apnea.

[0006] The main technologies of ventilators include: ventilation mode, control technology, measurement technology, ergonomics and display technology, as well as the overall supporting technology of core components. The proportional solenoid valve is a key component of the ventilator and is also regarded as the "pearl" in the crown of the valve. In the process of treating patients with difficulty in spontaneous breathing, doctors need to formulate different breathing assistance plans according to the patient's condition. The computer system then provides different currents to the proportional solenoid valve according to the different capacity regulations and requirements of gas release, thereby manipulating its opening size, thereby accurately controlling the flow rate of inlet and outlet gas, oxygen percentage and other parameters, and providing customized breathing assistance solutions.

[0007] The proportional solenoid valve is not a simple machined part. It has more than a dozen parts, which are combined together through electromagnetic force, elastic force, and precise transmission mechanism. The stroke of the middle valve plate is only a few tenths of a millimeter, which is equivalent to the width of a few strands of hair side by side. Such a motion trajectory places extremely high demands on motion control, reliable sealing, rubber manufacturing accuracy, and component pressure resistance. The proportional solenoid valve is an electrically controlled device. When it is powered on, the gas flows from one end of the solenoid valve to the other end. When it is powered off, the gas stops flowing.

[0008] In order to ensure the safety of patients during mechanical ventilation, the ventilator has strict requirements on the accuracy of flow control. The allowable flow error is usually within 10%. This parameter is also one of the important performance indicators for measuring the quality of the ventilator. The inhalation module of the ventilator is usually responsible for tracking the stable flow according to the instructions of the main control. In the air circuit of the inhalation module, the proportional solenoid valve plays a key role. There is a large pressure difference between the two ends of the proportional solenoid valve body. The airflow flows out through the small gap inside the valve body to form a sonic flow. The flow rate depends on the flow area of ​​the proportional solenoid valve. It is generally believed that the flow rate flowing through the proportional solenoid valve is in a linear function relationship with the coil current in the proportional valve. However, in actual applications, due to the transient characteristics of the proportional valve, the proportional valve cannot be controlled only based on this linear function relationship, but closed-loop control must be adopted.

[0009] As a key component of ventilator, proportional solenoid valve has the characteristics of good dynamic characteristics, high control accuracy and easy integration. In ventilator applications, both sides of the proportional solenoid valve are highly compressible gases, which leads to the system having time-varying, nonlinear and strong disturbance characteristics, making it difficult to establish an accurate mathematical model. Traditional PID controllers often rely on a certain mathematical model to adjust the parameters, and use a set of fixed parameters to complete the control task of the system, which is difficult to meet the control requirements of all set output flows at the same time. In the past decade, domestic and foreign scholars have conducted a lot of research on pneumatic proportional servo systems, and have made certain progress by applying the research results of control theory, such as adaptive control, fuzzy control, neural network control, variable structure control, and robust control. Among them, fuzzy control is an intelligent control method. It is suitable for controlling systems that are difficult to establish accurate mathematical models, have strong nonlinearity, and have large lags. It has strong robustness to changes in system parameters and strong anti-interference ability, and can achieve better control effects.

[0010] The proportional solenoid valve is based on proportional solenoid technology. It is a proportional control valve that uses a proportional solenoid as an electrical-mechanical conversion element. It converts the input current signal into a force and displacement mechanical signal output, thereby continuously and proportionally controlling the flow, pressure and direction of the hydraulic system. The output flow and pressure are not affected by load changes. Therefore, the valve opening can be adjusted by changing the input current, thereby realizing stepless flow regulation. It has the advantages of simple structure, easy processing, easy assembly, fast response, high reliability and low cost, and is very suitable for the application requirements of ventilator system flow regulation. However, general proportional solenoid valves have the following limitations in application: (1) They cannot adapt to high load conditions. When the working pressure is high or the valve diameter is large, a high pressure difference will be formed upstream and downstream of the valve, and a large electromagnetic force is required to overcome the pressure difference and open the valve. However, once the valve is opened, the pressure difference force will drop significantly, resulting in the force balance relationship of the valve core being broken, making it difficult for the valve armature to remain in a static throttling position. Therefore, most proportional solenoid valves can only be used in low load and low flow conditions. (2) The nonlinearity and hysteresis characteristics of the electromagnetic material BH curve will seriously affect the proportional characteristics of the valve current input and flow output, which is not conducive to the open-loop control of the system.

[0011] Specifically, the ventilators used in hospital clinics and medical emergency treatment need to have an output flow rate of 180L / min, and a main control valve group with extremely short response cycles and accurate distribution and mixing functions. For a more advanced ventilator, if it meets the above prerequisites, it can provide patients with adequate ventilation and extremely comfortable breathing support according to a certain control algorithm.

[0012] In addition, for the installation of the proportional solenoid valve in the ventilator, the proportional solenoid valve is generally bolted to the inlet and outlet tooling (for example, in patent CN215780800U). For the bolted connection on the inlet and outlet side, during installation, since the tooling surface is larger than the end face of the proportional solenoid valve, it is necessary to install the bolts from the valve seat side of the proportional solenoid valve. The bolt hole surface (due to the product size) is partially blocked by the shell. Therefore, during installation, it is necessary to disassemble the shell fastening nut of the proportional solenoid valve, remove the shell assembly, connect the valve seat to the tooling with bolts, then install the shell assembly back, and then install the fastening nut. The installation process is cumbersome; and, although the probability is small, it may still cause contamination of the device, slight deviation of the structure and magnetic field.

[0013] At the same time, in the prior art, in order to achieve stable electromagnetic force, a magnetic isolation ring structure is often required between the upper and lower iron cores, in order to change the magnetic circuit and lead to the armature, so that the electromagnetic force can be stable and the performance of the proportional solenoid valve can be improved. However, as a smart and tiny component, the addition of any additional components or parts will bring certain influences or risks to the manufacturing, assembly difficulty and precision. While pursuing the stability and customization of electromagnetic force, the simplification of structure, integration of components, or the extensive application of existing / original components are also very important factors that need to be considered. Summary of the invention

[0014] In view of the technical problems existing in the above-mentioned prior art regarding the integration of proportional solenoid valves, flow linear control and other requirements, the present invention provides an easily disassembled, intelligently controlled proportional solenoid valve device for a ventilator. The proportional solenoid valve of the present invention sets the valve sleeve as a magnetic isolation material to achieve a magnetic isolation effect, thereby increasing the magnetic flux in the armature; a guide sleeve with an oblique cut structure is set, which does not require thermal expansion installation and is easy to maintain; and the housing assembly of the proportional solenoid valve of the present invention is designed to be directly bolted to the inlet and outlet tooling, which is easy to install and disassemble the proportional solenoid valve. At the same time, the present invention also provides a method for accurately controlling the flow of each stage according to different characteristics and subdivided by PID closed-loop control, thereby optimizing the linearity of the flow curve of the gas medium supplied by the ventilator.

[0015] Specifically, in order to achieve the above purpose, the technical solution of the present invention is:

[0016] The first aspect of the present invention provides an easily disassembled intelligently controlled proportional solenoid valve for a ventilator, comprising a valve seat assembly, an armature assembly, a valve sleeve assembly, an adjustment assembly, a coil assembly and a housing assembly. The valve seat assembly is connected to a tooling for the inflow and outflow of a gas medium, and includes a valve seat, and is provided with an inlet channel and an outlet channel connected to the fluid; the adjustment assembly applies a pre-tightening force to the armature assembly (through a spring), and the coil assembly surrounds the outside of the valve sleeve assembly to provide a magnetic field for the armature assembly, so that the armature assembly is displaced in the valve sleeve assembly to control the on-off (connection and blocking) between the inlet channel and the outlet channel; the valve sleeve assembly is connected to the valve seat assembly and is located on the side of the valve seat away from the tooling.

[0017] Furthermore, the housing assembly includes three brackets located at both ends of the coil assembly and assembled on the valve sleeve assembly, a lining plate and an injection molded housing for pressing the bracket to the valve sleeve assembly; the injection molded housing has an extension hole of the bolt hole in the valve seat for connecting the tooling, which is used to use long bolts to fasten the housing to the tooling as a whole; the circuit board in the coil assembly is located in the injection molded housing, which is used to control the current of the coil in the coil assembly. Among them, the lining plate presses the bracket to the valve sleeve assembly (the sealing connection between the valve sleeve and the valve seat) and fastens the lining plate and the valve seat by bolts, thereby fixing the bracket. The bracket is made of magnetic conductive material. The injection molded housing is integrally formed by injection molding, which protects the interior of the proportional solenoid valve and forms an integral device, which is convenient for matching various target ventilators and easy to install and disassemble.

[0018] Preferably, the injection molded housing and the valve seat assembly form a rectangular solid body, and except for the protruding surface where the circuit board is provided, the three brackets are respectively located on the other three side surfaces of the injection molded housing as internal supports.

[0019] Preferably, the valve sleeve assembly includes a valve sleeve, an adjustment seat and a seal (preferably, a sealing ring) for achieving a sealed connection with the valve seat assembly; wherein the valve sleeve and the adjustment seat are welded as a whole, respectively cooperate with the armature assembly and the adjustment assembly, and respectively provide movement guides for the armature assembly and the adjustment assembly; the valve sleeve is made of a magnetic isolation material. The effect of the magnetic isolation ring can be achieved through the valve sleeve, and the magnetic flux in the armature can be increased. There is no need to design a magnetic isolation ring, and the structure is simpler. Preferably, in the direction of the coil, the length of the valve sleeve on the side away from the valve seat should exceed the distal surface of the armature (the side away from the valve seat), but not exceed the distal end of the coil. The thickness of the valve sleeve (the guide part that accommodates the armature) is preferably between 0.5-1.5 mm. Too thin or too thick will cause the electromagnetic force to become smaller.

[0020] Preferably, the valve seat assembly further comprises an air inlet sealing ring and an air outlet sealing ring, which respectively seal the air inlet channel and the air outlet channel.

[0021] Preferably, the armature assembly includes an armature, a sealing block and a guide sleeve. Wherein, the armature, under the action of the magnetic field of the coil assembly and the spring of the regulating assembly, pushes the sealing block to reciprocate, thereby realizing the opening and closing control (and flow control) of the air inlet of the air inlet channel by the sealing block; the armature has two through holes on the left and right sides for balancing the air pressure on the regulating assembly side and the valve seat side; the guide sleeve is installed in the corresponding groove on the outer surface of the armature, and is used to abut / contact the valve sleeve. When subjected to the magnetic field force, the armature overcomes the friction between the guide sleeve and the valve sleeve to guide and move in the valve sleeve. The guide sleeve is a cylindrical surface structure with an oblique fracture. Based on this oblique fracture, the guide sleeve does not need to be thermally expanded during installation, and can be directly snapped in for installation, which is convenient for maintenance.

[0022] Preferably, the adjustment assembly includes a spring, an adjustment rod and a seal. The two ends of the spring respectively abut against the adjustment rod and the spring groove reserved in the armature; the adjustment rod is connected to the adjustment seat through threads, and is sealed by the seal (preferably a sealing ring); the position of the adjustment rod is adjusted by the threads to adjust the preload force of the spring connected to the adjustment rod (the other end) on the armature.

[0023] Preferably, the coil assembly includes a coil frame, a coil and a circuit board. The circuit board is placed in the protruding end of the injection molded shell to control the current of the coil; the coil is arranged around the coil frame to provide the required magnetic field for the armature. The circuit board is written with a control algorithm to control the coil current and optimize the linearity of the flow curve. The circuit board can also modify the program according to the needs of different working modes, which is convenient for product upgrading and modification, and increases the scalability of the proportional solenoid valve.

[0024] In addition, the second aspect of the present invention also provides an intelligent and precise control method for a proportional solenoid valve. When the proportional solenoid valve is working, due to the combined effects of many factors such as the hysteresis effect of the magnetic material, the gas medium pressure, the spring force and the friction force, the relationship curve between the gas flow output by the proportional solenoid valve and the input current changes continuously. For example, Figure 5The flow curve is shown in the figure when the current gradually decreases from 0A to the maximum and then to 0A. Among them, the electromagnet (armature) in the proportional solenoid valve requires a certain current to open (starting current). After opening, the slope of the flow curve is small in the early stage (Q0 to Q1), the slope is large in the middle stage (Q1 to Q2), and the slope is small in the later stage (Q2 to Q3). In addition, the flow curve with decreasing current and the flow with increasing current will produce hysteresis. In addition, when the current greater than the starting current is used as the starting current, different starting currents will also produce different flow curves. The above characteristics ultimately cause a certain (uncertain / stable) error between the actual flow obtained and the set flow value corresponding to the set current, making the output flow inaccurate.

[0025] In response to this technical problem, the present invention also provides an intelligent and precise control method for a proportional solenoid valve, which uses a PID closed-loop control method to achieve precise flow control. Based on the actual flow value fed back by the system, a PID algorithm is used to control the current of the proportional solenoid valve in real time, thereby achieving precise output of the flow of the proportional solenoid valve.

[0026] Specifically, an intelligent and precise control method for a proportional solenoid valve comprises the following steps:

[0027] (1) According to the slope characteristics of the flow curve of the proportional solenoid valve, and the range of the actual flow Qc and the flow change ΔQ, the flow Q is divided into several intervals; each interval has a set of PID control parameters; wherein the flow change ΔQ is the difference between the target flow Qt and the actual flow Qc;

[0028] (2) According to the flow regulation range of each interval, the PID parameters of each interval are debugged, and the PID parameters of each interval are determined accordingly;

[0029] (3) According to the PID parameters determined in each interval, they are stored in the storage module, and the control program is written into the chip of the circuit board. When using a proportional solenoid valve, the program will select the corresponding interval and automatically call the matching PID parameters based on the detected actual flow Qc and the flow difference ΔQ, thereby outputting the corresponding current signal to achieve real-time flow control.

[0030] Preferably, the PID parameter debugging consists of three parts: proportional adjustment, integral adjustment, and differential adjustment; wherein the PID parameters include the proportional parameter K p , integration parameter K i and the differential parameter K d .

[0031] Preferably, in step (3), the output current signal u(t) is calculated according to the following formula:

[0032] u(t)=K p *ΔQ(t)+K i *∫ΔQ(t)dt+K d *dΔQ(t) / dt

[0033] in,

[0034] t is time;

[0035] u(t) is the output current signal at time t;

[0036] K p is the scale parameter;

[0037] K i is the integration parameter;

[0038] K d is the differential parameter; and

[0039] ΔQ(t) is the difference between the target flow rate Qt and the detected actual flow rate Qc at time t.

[0040] Furthermore, the PID parameter debugging in step (2) is generally implemented by the following steps:

[0041] a. Determine the scale parameter K p :First, let K i =0, K d =0, making PID pure proportional regulation; then, gradually increase the proportional parameter from 0 until the system (the output signal of the PID regulation system) oscillates, and then obtain the oscillation proportional parameter K p1 ; Then from the oscillation ratio parameter K p1 Gradually decrease until the system oscillation disappears, then obtain the proportional parameter K p2 ; Thus, the proportional parameter K is set p K p2 60% to 70%;

[0042] b. Determine the integral parameter K i : Proportional parameter K p After confirmation, set a larger initial value of the integral parameter K i0 , by K io Gradually decrease until the system oscillates (K i1 ), and then gradually increase until the system oscillation disappears, then the integral parameter K is obtained i2 ; Thus, set the PID integral parameter K i K i2 150% to 180%;

[0043] c. Determine the differential parameter K d : In the scale parameter K p and the integration parameter Ki After setting, the differential parameter K d can be set to 0; or, alternatively, in the ratio parameter K p and the integration parameter K i After setting, gradually increase the differential parameter from 0 until the oscillation disappears. At this time, the differential parameter K is obtained. d1 , and the differential parameter K d Set to K d1 30% of.

[0044] Furthermore, the method further comprises a step (2') between the step (2) and the step (3), which is: repeating the steps (1) to (2) to obtain updated PID parameters.

[0045] In addition, the third aspect of the present invention also provides an intelligent and precise control system for a proportional solenoid valve, including: a flow sensor for obtaining the current / actual flow Qc; an acquisition module for setting a target flow Qt; a calculation module for calculating the difference ΔQ based on the target flow Qt and the actual flow Qc; a PID parameter storage and calling module for storing PID parameters adjusted by PID parameters, and calling matching PID parameters based on the actual flow Qc and the difference ΔQ; a control module, which controls the current of the proportional solenoid valve through a PID algorithm based on the currently called PID parameters until the actual flow value fed back by the flow sensor is equal to the set target value Qt.

[0046] On the basis of the above scheme, the easily disassembled intelligent control proportional solenoid valve for a ventilator provided by the present invention has the following advantages:

[0047] The housing component design of the proportional solenoid valve provided by the present invention can be installed on the air inlet and outlet tooling without disassembling the proportional solenoid valve.

[0048] The guide sleeve of the armature has an oblique opening structure, which does not require thermal expansion during installation and can be directly installed, making maintenance easier.

[0049] The valve sleeve is made of magnetic isolation material, and the effect of magnetic isolation ring can be achieved through the valve sleeve, which increases the magnetic flux in the armature. There is no need to design a magnetic isolation ring, and the structure is simpler.

[0050] The conventional proportional solenoid valve flow curve is nonlinear. The present invention adds an intelligent control chip to improve the linearity of the proportional solenoid valve flow curve by adjusting the current change under different duty cycles. The circuit board in the proportional solenoid valve can modify the program according to the needs of different working modes, which is convenient for product upgrading and modification, and increases the scalability of the proportional solenoid valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1It is a structural cross-sectional view of an easily disassembled intelligent control proportional solenoid valve for a ventilator according to the present invention.

[0052] Figure 2 It is a product axial side schematic diagram of the unmolded housing of the easily disassembled intelligent control proportional solenoid valve for a ventilator of the present invention.

[0053] Figure 3 It is a schematic diagram of the product axial side of the injection-molded shell of the easily disassembled intelligent control proportional solenoid valve for a ventilator of the present invention.

[0054] Figure 4 The diagram is a schematic diagram of the external structure of the armature assembly of the easily disassembled intelligent control proportional solenoid valve for a ventilator according to the present invention.

[0055] Figure 5 It is the relationship curve between the flow rate and current of the proportional solenoid valve.

[0056] Figure 6 It is a schematic diagram of the method of PID controlling the flow of a proportional solenoid valve.

[0057] Figure 7 It is a flow chart of a system and method for real-time flow control according to the method of the present invention. DETAILED DESCRIPTION

[0058] The “easy-to-detach intelligent controlled proportional solenoid valve for a ventilator” of the present invention is further described below in conjunction with the accompanying drawings.

[0059] like Figure 1-4 The easily disassembled intelligent control proportional solenoid valve for a ventilator shown in the figure is composed of a valve seat assembly, an armature assembly, a valve sleeve assembly, an adjustment assembly, a coil assembly and a housing assembly.

[0060] Specifically, the valve seat assembly includes a valve seat 11, an outlet sealing ring 12 and an inlet sealing ring 13, which respectively seal the outlet channel (such as Figure 2 As shown in the figure, there are four air outlets in the top outer ring) and an air inlet channel (as shown in the figure Figure 2 As described in the figure, there is an air inlet channel at the top center), and the valve seat assembly is used for the inflow and outflow of gas medium. The valve seat 11 is provided with an air inlet channel and four air outlet channels, and the two channels are fluidly connected. Figure 1 As shown in the figure, the air inlet of the air inlet channel in the valve seat cavity is arranged opposite to the sealing block 22 in the armature assembly, and the sealing block 22 is used to control the connection and blocking of the air inlet with the valve seat cavity (air outlet channel). At the same time, the valve seat 11 is also provided with four bolt holes (outermost on the top surface) that match the tooling, and is used to be connected to the target tooling by means of bolts.

[0061] The armature 21, the sealing block 22 and the guide sleeve 23 form an armature assembly. The armature 21 is in the longitudinal direction (such as Figure 1 Under the force of the armature 21, it moves up and down in the cavity defined by the valve seat assembly, thereby driving the sealing block 22 (fixed connection), so that the sealing block 22 and the valve seat 11 (the air inlet in the cavity) can be opened and closed to control the outlet gas flow rate. There are two through holes on the left and right sides of the armature 21 to control the balance of the air pressure in the valve. Figure 4 , which is a schematic diagram of the outer structure of the armature assembly, wherein the guide sleeves 23 (two) are cylindrical structures with oblique fractures, which can be directly slightly deformed and inserted into the slots provided on the outer surface of the armature, making installation and maintenance easier. The guide sleeve 23 is the contact surface between the armature assembly and the valve sleeve 31, and is used for the friction movement of the armature 21 in the cavity defined by the valve sleeve 31.

[0062] The valve sleeve 31 and the adjusting seat 32 are welded as a whole, and together with the sealing ring 33, form a valve sleeve assembly. When the proportional solenoid valve is working, the armature assembly moves up and down in the valve sleeve assembly, and there is friction between the guide sleeve 23 and the valve sleeve 31.

[0063] The spring 41, the adjusting rod 42 and the sealing ring 43 form an adjusting assembly. The adjusting rod 42 is connected to the adjusting seat 32 by threads and sealed by the sealing ring 43. By adjusting the position of the adjusting rod 42, the preload force of the spring can be adjusted to control the performance of the proportional solenoid valve.

[0064] The coil frame 51, the coil 52 and the circuit board 53 together form a coil assembly. When the coil is energized, a magnetic field is generated to control the displacement of the armature 21. The circuit board is written with a control algorithm to control the coil current and optimize the linearity of the flow curve.

[0065] The bracket 61, the bracket 62, the bracket 63, the lining plate 64 and the injection molded shell 65 constitute a shell assembly. The two ends of the bracket 61, the bracket 62 and the bracket 63 are respectively located at the two ends of the coil assembly and abut against the lower surface of the valve sleeve 31 (where the valve seat 11 is sealed). The lining plate 64 and the valve seat 11 are fastened by bolts to press the brackets 61-63 (and the valve sleeve 31) between the two. The proportional solenoid valve shell 65 is formed by injection molding to protect the proportional solenoid valve. Preferably, as Figure 2 As shown in , the liner 64 has holes at four corners corresponding to the four tooling mounting holes of the valve seat 11, and the lines connecting the holes of the liner 64 and the mounting holes of the valve seat 11 form extension holes in the injection molding 65 for bolt fastening. Preferably, two diagonal holes can be selected to first fasten the liner 64 and the brackets 61-63 to the valve seat 11 (through short bolts), and the proportional solenoid valve obtained after injection molding is installed for the target tooling through the other two diagonal holes (long bolts).

[0066] Specifically, the working principle of the proportional solenoid valve provided by the present invention is as follows:

[0067] See also Figure 1 When no power is supplied, the proportional solenoid valve is in a normally closed state, and the spring 41 has a certain preload force, which pushes the armature 21 and the sealing block 22 against the air inlet of the valve seat 11, and the sealing block 22 blocks the inflow of the gas medium. When the coil 52 is energized, due to the magnetic isolation effect of the valve sleeve 31, the magnetic path generated enters the armature 21 from the adjustment seat 32 to generate electromagnetic force. The electromagnetic force overcomes the pressure of the spring 41 and the friction between the guide sleeve 23 and the valve sleeve 31 to move the armature 21 downward, and the valve (air inlet) opens, and the medium flows in. The displacement of the armature 21 changes with the change of the coil current, thereby controlling the flow rate of the proportional solenoid valve. The preset program in the circuit board 53 can control the change of the actual current in the electric coil to correct the flow curve of the medium, so that it can change linearly, thereby realizing the proportional control of the medium flow rate.

[0068] See also Figure 2 , circular holes are dug in brackets 61 to 63, which are used to reduce weight on the one hand, and to improve the strength of the shell by allowing sufficient material flow during injection molding of the shell on the other hand. The circuit board in the proportional solenoid valve can modify the program according to the needs of different working modes, which is convenient for product upgrades and increases the scalability of the proportional solenoid valve.

[0069] In addition, the present invention also provides an intelligent and precise control method for a proportional solenoid valve. Figure 6 As shown. The PID controller consists of three parts: proportional regulation, integral regulation, and differential regulation. Proportional regulation adjusts the output according to the size of the deviation, integral regulation adjusts the output by integrating the deviation, and differential regulation adjusts the output according to the differential of the deviation. The expression of the PID algorithm is:

[0070] u(t)=K p *ΔQ(t)+K i *∫ΔQ(t)dt+K d *dΔQ(t) / dt

[0071] in:

[0072] t: time

[0073] u(t): output current signal of PID controller at time t

[0074] Kp: proportional parameter;

[0075] Ki: integration parameter;

[0076] Kd: differential parameter;

[0077] ΔQ(t): The difference between the target flow rate Qt and the actual flow rate Qc at time t.

[0078] Specifically, the overall intelligent and precise debugging control process of the proportional solenoid valve is as follows:

[0079] (1) According to the flow curve characteristics (slope) of the proportional solenoid valve, and based on the range of the actual flow Qc and the flow change / difference ΔQ, the flow is divided into several groups of intervals (such as Figure 5 the three groups shown), and each group corresponds to a set of PID control parameters.

[0080] (2) Conduct PID control parameter debugging for each group of flow adjustment ranges respectively.

[0081] (3) Store each set of PID parameters obtained from the debugging into the storage module, and write the control program into the chip. When using the proportional solenoid valve, the program will automatically call the matching PID parameters according to the values of the actual flow Qc and the flow difference ΔQ to control the output current signal of the flow.

[0082] Among them, in step (1), according to the characteristics of the flow-current curve of the proportional solenoid valve, the flow of the proportional solenoid valve is divided into three intervals, Q0, Q1, Q2, Q3. When the flow Qc < Q1, it is in the opening stage of the proportional solenoid valve. At this time, the slope of the flow-current curve is small, and the flow rises gently. When Q1 < Qc < Q2, the slope of the flow-current curve is large, and the flow rises rapidly. When the flow is in Q2 < Qc < Q3, the stroke of the proportional solenoid valve is the largest. At this time, if the current is increased continuously, the flow will remain unchanged.

[0083] If necessary, the flow range can be divided into more intervals, and the changes in different intervals correspond to different parameters to adapt to the rapid response of the flow.

[0084] In step (2), the general steps of the parameter adjustment process are as follows:

[0085] a. Determine the proportional parameter Kp: When determining the proportional parameter Kp, first remove the integral term and the derivative term of the PID, generally by setting Ki = 0 and Kd = 0 to make the PID a pure proportional regulation. Gradually increase the proportional parameter Kp from 0 until the system (the output current signal of the PID regulation system) oscillates; then, conversely, gradually decrease the proportional parameter Kp from this point until the system oscillation disappears, record the proportional parameter Kp at this time, and set the proportional parameter Kp of the PID to 60% - 70% of the current value. The debugging of the proportional parameter Kp is completed.

[0086] b. Determine the integral parameter Ki: After determining the proportional parameter Kp, set a large initial value of the integral parameter Ki, and then gradually decrease Ki until the system oscillates. Then, conversely, gradually increase Ki until the system oscillation disappears. Record Ki at this time, and set the integral parameter Ki of the PID to 150% - 180% of the current value. The debugging of the integral parameter Ki is completed.

[0087] c. Determine the integral parameter Kd. The integral parameter Kd generally does not need to be set and can be 0. If it is to be set, gradually increase the integral parameter Kd from 0 until the oscillation disappears, and finally Kd is 30% of the current value.

[0088] The control process of the control system when the proportional solenoid valve is used:

[0089] Figure 7 The flow control system and flow chart when the proportional solenoid valve is used. Module M1 is a flow sensor, which is used to obtain the actual flow Qc (i.e., the current flow); module M2 is an acquisition module, which is used to obtain the set target flow value Qt; module M3 is a calculation module, which is used to calculate the difference ΔQ between the target flow Qt and the current flow Qc; M4 is a PID parameter storage module, which is used to store the PID parameters of each interval obtained by PID parameter adjustment. When adjusting the flow, the corresponding PID parameters are called according to the values ​​of Qc and Qt and transmitted to module M5. Module M5 is a control module, which is used to control the current of the proportional solenoid valve through the PID algorithm according to the current PID parameters until the flow value fed back by the M1 module is equal to the set target value Qt.

[0090] It should be understood that the directional indications such as "left", "right", "upper", and "lower" described herein are divided according to the directions of the devices shown in the figures. It should be understood that in the scheme of the present invention, the positions such as left, right, upper, and lower are interchangeable and do not constitute a substantial limitation to the scheme.

[0091] The examples described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design concept of the present invention, any simple modifications, equivalent changes and modifications made to the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. An intelligent and precise control method for a proportional solenoid valve, characterized in that: The method comprises the following steps: (1) The flow rate Q is divided into several intervals according to the slope characteristics of the flow rate curve of the proportional solenoid valve, and the range of the actual flow rate Qc and the flow rate change ΔQ; wherein the flow rate change ΔQ is the difference between the target flow rate Qt and the actual flow rate Qc; (2) According to the flow regulation range of each interval, the PID parameters of each interval are debugged, and the PID parameters of each interval are determined accordingly; (3) According to the PID parameters determined in each interval, the matching PID parameters are automatically called based on the detected actual flow rate Qc and the flow rate difference ΔQ, thereby outputting the corresponding current signal to achieve flow control.

2. The intelligent and precise control method of the proportional solenoid valve according to claim 1 is characterized in that: PID parameter debugging consists of three parts: proportional adjustment, integral adjustment, and differential adjustment; among them, the PID parameters include the proportional parameter K p , integration parameter K i and the differential parameter K d .

3. The intelligent and precise control method of the proportional solenoid valve according to claim 1 or 2, characterized in that: In the step (3), the output current signal is calculated according to the following formula: u(t)=K p *ΔQ(t)+K i *∫ΔQ(t)dt+K d *dΔQ(t) / dt in, t is time; u(t) is the output current signal; K p is the scale parameter; K i is the integration parameter; K d is the differential parameter; and ΔQ(t) is the difference between the target flow rate Qt and the detected actual flow rate Qc.

4. The intelligent and precise control method of a proportional solenoid valve according to any one of claims 1 to 3, characterized in that: The PID parameter debugging in step (2) is achieved by the following steps: a. Determine the scale parameter K p :First set K i =0, K d =0, making PID pure proportional regulation; then, gradually increase the proportional parameter from 0 until the system oscillates, and then obtain the oscillation proportional parameter K p1 ; Then from the oscillation ratio parameter K p1 Gradually decrease until the system oscillation disappears, then obtain the proportional parameter K p2 ; Set the proportional parameter K p K p2 60% to 70%; b. Determine the integral parameter K i : Proportional parameter K p After confirmation, set a larger initial value of the integral parameter K i0 , by K i0 Gradually reduce until the system oscillates, and then gradually increase until the system oscillation disappears. At this time, the integral parameter K is obtained. i2 ; Set the integral parameter K i K i2 150% to 180%; c. Determine the differential parameter K d : Differentiation parameter K d It can be set to 0; or, gradually increase the differential parameter from 0 until the oscillation disappears, then obtain the differential parameter K d1 , and the differential parameter K d Set to K d1 30% of.

5. An intelligent precision control system for a proportional solenoid valve, characterized in that: Real-time systems include: Flow sensor, used to obtain actual flow Qc; Acquisition module, used to set the target flow rate Qt; a calculation module, for calculating a flow difference ΔQ according to the target flow Qt and the actual flow Qc; a PID parameter storage and calling module, for storing PID parameters adjusted by PID parameters, and calling matching PID parameters according to the actual flow Qc and the flow difference ΔQ; and The control module controls the current of the proportional solenoid valve through the PID algorithm according to the called PID parameters until the actual flow value fed back by the flow sensor is equal to the set target flow Qt.

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