A high-voltage electro-pneumatic position servo system and control method

Abstract

The application discloses a high-pressure electric-gas position servo system and a control method, and belongs to the field of pneumatic position servo control. The system comprises a first electromagnetic on-off valve, a high-pressure electric-gas servo valve, a second electromagnetic on-off valve, a third electromagnetic on-off valve, a double-rod double-acting air cylinder and a position sensor. The first electromagnetic on-off valve is connected with the high-pressure electric-gas servo valve. One working port of the high-pressure electric-gas servo valve is connected with one cavity of the double-rod double-acting air cylinder through the second electromagnetic on-off valve, and the other working port of the high-pressure electric-gas servo valve is connected with the other cavity of the double-rod double-acting air cylinder through the third electromagnetic on-off valve. One end of the piston rod of the double-rod double-acting air cylinder is connected with a load, and the other end is abutted against the position sensor. The system and the control method can improve the control precision and stability of the system, and realize high-response and high-precision control of the high-pressure pneumatic position servo system.

Description

Technical Field

[0001] This invention belongs to the field of pneumatic position servo control, and more specifically, relates to a high-voltage electro-pneumatic position servo system and control method. Background Technology

[0002] Pneumatic position servo systems use compressed air as the working medium and have advantages such as being clean and pollution-free, having a fast response speed, and a high power-to-weight ratio, making them widely used in fields such as industrial automation, medical devices, energy and chemical industry, aerospace, and national defense.

[0003] Existing pneumatic position servo systems suffer from poor stability and high control difficulty under high pressure. Furthermore, their simple air circuits lead to significant leakage, low energy utilization, and low control accuracy. Moreover, high-pressure electro-pneumatic position servo systems are highly nonlinear and uncertain. In existing direct adaptive control methods, the key parameters in the adaptive law are driven by the system's state error. When the state error is small (i.e., when the cylinder and command positions are close), the corresponding key parameters are also small, making it difficult to accurately estimate the system's uncertain parameters and thus hindering high-precision control. In high-pressure electro-pneumatic position servo systems, "high pressure" refers to an air source pressure exceeding 1 MPa, typically between 1 and 40 MPa. Additionally, existing methods for estimating disturbances in the state equations generally obtain velocity through measurement. However, velocity measurement typically introduces measurement noise, which affects the accuracy of unknown disturbance estimation and further impacts the controller's precision. Summary of the Invention

[0004] In view of the shortcomings of the existing technology and the need for improvement, the present invention provides a high-voltage electro-pneumatic position servo system and control method, the purpose of which is to improve the control accuracy of the high-voltage electro-pneumatic position servo system.

[0005] To achieve the above objectives, according to a first aspect of the present invention, a high-pressure electro-pneumatic position servo system is provided, comprising: a high-pressure electro-pneumatic servo valve, a first electromagnetic switch valve, a second electromagnetic switch valve, a third electromagnetic switch valve, a double-rod double-acting cylinder, and a position sensor.

[0006] The first electromagnetic switch valve is connected to the high-pressure electro-pneumatic servo valve, and the first electromagnetic switch valve is also connected to a gas source; one working port of the high-pressure electro-pneumatic servo valve is connected to one chamber of the double-rod double-acting cylinder through the second electromagnetic switch valve, and the other working port of the high-pressure electro-pneumatic servo valve is connected to the other chamber of the double-rod double-acting cylinder through the third electromagnetic switch valve.

[0007] One end of the piston rod of the double-rod double-acting cylinder is used to connect to the load, and the other end abuts against the position sensor.

[0008] Furthermore, it also includes: a first damping hole and a second damping hole respectively disposed on the two chambers of the double-rod double-acting cylinder; wherein, the diameter r1 of the first damping hole and the second damping hole is smaller than the diameter r2 of the high-pressure electro-pneumatic servo valve, and the difference between r1 and r2 is greater than a set threshold.

[0009] The first electromagnetic switch valve is connected to the two chambers of the double-rod double-acting cylinder through the first damping orifice and the second damping orifice, respectively.

[0010] Furthermore, it also includes: a first check valve and a second check valve;

[0011] The first check valve is disposed between the first electromagnetic switch valve and the first damping orifice; the second check valve is disposed between the first electromagnetic switch valve and the second damping orifice.

[0012] Furthermore, the high-pressure electro-pneumatic servo valve is a single-stage slide valve servo valve directly driven by a voice coil motor, and the valve core position is controlled by a closed loop.

[0013] According to a second aspect of the present invention, a control method for a high-voltage electro-pneumatic position servo system as described in any one of the first aspects is provided, comprising:

[0014] S1. Open the first, second, and third solenoid valves, and acquire the position signal x1 of the double-acting cylinder piston rod and the position command x of the load. 1d ;

[0015] S2, Connect the position signal x1 with the position command x of the load. 1d After comparison, the tracking error z1 of the piston rod of the double-rod double-acting cylinder is obtained;

[0016] S3. Use the constructed state observer without velocity feedback to observe the external disturbance x of the system. e Make an estimate and utilize the estimated external disturbance. The tracking error z1 is used to calculate the position control signal u of the high-voltage electro-pneumatic servo valve core; the state observer is:

[0017]

[0018]

[0019]

[0020] Where x = [x1, x2, x3] TThe state of the state observer; This represents the derivative of parameter a with respect to time. This represents the estimated value of parameter a. m is the mass of the piston rod and the load; P1 and P2 are the air pressures in the two chambers of the double-rod double-acting cylinder, respectively; A a Let be the area of ​​the piston. Let θ1 and θ2 be functions of the direction of frictional force, respectively, and let ω0 > 0 be the bandwidth of the state observer. For observation error,

[0021] S4. Use the position control signal u to control the position of the high-voltage electro-pneumatic servo valve core, thereby controlling the load position.

[0022] Furthermore, S3 also includes: estimating parameters θ1 and θ2, where the adaptive rate for estimating parameters θ1 and θ2 is:

[0023]

[0024]

[0025] in, Pick or i takes the value 1 or 2, θ max =[θ 1max ,θ 2max ] T Let θ1 and θ2 be the upper bounds, and θ min =[θ 1min ,θ 2min ] T Let θ1 and θ2 be the lower bounds; Γ be the gain of the adaptive rate; τ be the key parameter, expressed as:

[0026] τ=ψ2γ2

[0027]

[0028]

[0029] Furthermore, in S3, the estimated external disturbance is utilized. The position control signal u of the high-voltage electro-pneumatic servo valve core, calculated from the tracking error z1, is as follows:

[0030]

[0031]

[0032]

[0033] Where k is the adiabatic index of air, R is the ideal gas constant, T1 and T2 are the temperatures of the two chambers, V1 and V2 are the initial volumes of the two chambers, C1 and C2 are the corresponding coefficients of the two chambers, and u s α2 is the robust suppression term; α3 is the virtual control law for the state variable x3, and its formula is:

[0034]

[0035] In the formula, α1 is the virtual control law for the state variable x2. The position instruction x indicates the load. 1d The second derivative of , where k2 is a preset control parameter.

[0036] Furthermore, when the system further includes a first damping hole and a second damping hole respectively disposed on the two chambers of the double-rod double-acting cylinder, before S1, it further includes:

[0037] Control the opening of the first solenoid valve and the closing of the second and third solenoid valves;

[0038] The air source pre-charges the two chambers of the double-rod double-acting cylinder through the first electromagnetic switch valve, the first damping orifice, and the second damping orifice to adjust the initial pressure of the two chambers.

[0039] Furthermore, when the system also includes a first check valve and a second check valve, after S4, it further includes:

[0040] The high-pressure electro-pneumatic servo valve is controlled by the two chambers of a double-rod double-acting cylinder to maintain a stable load position.

[0041] Close the first, second, and third solenoid valves to lock the load position.

[0042] According to a third aspect of the present invention, an intelligent controller is provided, including a computer-readable storage medium and a processor;

[0043] The computer-readable storage medium is used to store executable instructions;

[0044] The processor is configured to read executable instructions stored in the computer-readable storage medium and execute the control method described in any of the second aspects.

[0045] In summary, the above-described technical solutions conceived in this invention can achieve the following beneficial effects:

[0046] (1) The high-pressure electro-pneumatic position servo system of the present invention is a pneumatic position servo system constructed by a high-pressure electro-pneumatic servo valve and three electromagnetic switch valves. The high-pressure electro-pneumatic servo valve is used as the servo amplification element of the system to accurately control the air flow and control speed entering the two chambers of the cylinder. The electromagnetic switch valve is used to control the opening and closing of the air path, which can improve the response speed and control accuracy of the system.

[0047] (2) Furthermore, before the system moves, the two chambers of the double-rod double-acting cylinder are pre-charged with damping holes, which increases the stiffness of the high-pressure electro-pneumatic position servo system and improves the stability of system control. At the same time, the difference between the diameter of the two damping holes and the diameter of the high-pressure electro-pneumatic servo valve is greater than the set threshold, which can reduce the influence of the damping holes on the pressure of the two chambers during control.

[0048] (3) Furthermore, in order to prevent the two chambers of the double-rod double-acting cylinder from being connected by the damping orifice, a check valve is installed in front of the damping orifice, which further improves the reliability of the system.

[0049] (4) The high-voltage electro-pneumatic position servo system control method of the present invention characterizes external disturbance x. e During estimation, the constructed state observer without velocity feedback outputs no velocity feedback, allowing for direct and simultaneous estimation of the external disturbance x. e And the state variable x2 representing velocity, there is no external disturbance x that affects the measurement noise introduced during velocity measurement. e The accuracy of the estimation can improve the precision of control.

[0050] (5) Further, in the high-voltage electro-pneumatic position servo system control method of the present invention, when estimating the parameters θ1 and θ2 characterizing the viscous damping coefficient and the Coulomb friction coefficient, the key parameter τ in the adaptive law is not related to the system's state error, but is directly driven by the error of parameters θ1 and θ2. As long as there is an error in parameters θ1 and θ2, the error can be estimated until the true value of parameters θ1 and θ2 is estimated. Therefore, the indirect adaptive law designed in this invention can accurately estimate parameters θ1 and θ2, further improving the control accuracy of the controller. At the same time, parameters θ1 and θ2 also serve as one of the inputs of the state observer without velocity feedback. Improving the estimation accuracy of parameters θ1 and θ2 can further improve the observer's accuracy in observing system disturbances, further realizing high-precision control of the system.

[0051] In summary, the high-voltage electro-pneumatic position servo system and its control method provided by this invention have a simple structure, fast and accurate response, improve the control accuracy and stability of the system, and realize high-response and high-precision control of the high-voltage pneumatic position servo system. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the high-voltage electro-pneumatic position servo system of the present invention.

[0053] Figure 2 The figures show the tracking curves of the step reference signal for different control methods in the embodiments of the present invention.

[0054] Figure 3 This refers to the tracking error of the step reference signal by different control methods in the embodiments of the present invention.

[0055] Figure 4 The figures show the tracking curves of the sinusoidal reference signal for different control methods in the embodiments of the present invention.

[0056] Figure 5 This refers to the tracking error of the sinusoidal reference signal by different control methods in the embodiments of the present invention.

[0057] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0058] 1-Gas source; 2-First solenoid switch valve; 3-First check valve

[0059] 4-High-pressure electro-pneumatic servo valve; 5-Second check valve; 6-Second solenoid switch valve

[0060] 7-Third electromagnetic switch valve; 8-First damping orifice; 9-Second damping orifice

[0061] 10-Double-acting cylinder with double lever; 11-Position sensor; 12-Intelligent controller Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0063] In this invention, the terms "first," "second," etc., used in the invention and accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0064] like Figure 1 As shown, the high-voltage electro-pneumatic position servo system of the present invention mainly includes: a first electromagnetic switch valve 2, a high-voltage electro-pneumatic servo valve 4, a second electromagnetic switch valve 6, a third electromagnetic switch valve 7, a double-rod double-acting cylinder 10, a position sensor 11, and an intelligent controller 12.

[0065] One end of the piston rod of the double-rod double-acting cylinder 10 is connected to the load, and the other end of the piston rod abuts against the position sensor 11;

[0066] The first electromagnetic switch valve 2 is connected to the high-pressure electro-pneumatic servo valve 4, and the first electromagnetic switch valve 2 is also connected to the air source 1, so that the air source 1 is connected to the high-pressure electro-pneumatic servo valve 4 through the first electromagnetic switch valve 2; one working port of the high-pressure electro-pneumatic servo valve 4 is connected to one chamber of the double-rod double-acting cylinder 10 through the second electromagnetic switch valve 6, and the other working port of the high-pressure electro-pneumatic servo valve 4 is connected to the other chamber of the double-rod double-acting cylinder 10 through the third electromagnetic switch valve 7; in this embodiment of the invention, the two chambers of the double-rod double-acting cylinder 10 are respectively referred to as chamber A and chamber B.

[0067] The intelligent controller 12 is electrically connected to the first electromagnetic switch valve 2, the high-pressure electro-pneumatic servo valve 4, the second electromagnetic switch valve 6, the third electromagnetic switch valve 7, and the position sensor 11.

[0068] Furthermore, the high-voltage electro-pneumatic position servo system of the present invention also includes an air source 1.

[0069] To improve the control stiffness of the high-voltage electro-pneumatic position servo system and thus enhance the stability of load position control, the high-voltage electro-pneumatic position servo system in this embodiment of the invention further includes: a first damping hole 8 and a second damping hole 9 respectively disposed on the two chambers of the double-rod double-acting cylinder 10; a first electromagnetic switch valve 2 connected to chamber A of the double-rod double-acting cylinder 10 through the first damping hole 8; and the first electromagnetic switch valve 2 connected to chambers A and B of the double-rod double-acting cylinder 10 through the second damping hole 9.

[0070] The diameter r1 of the first damping orifice 8 and the second damping orifice 9 is smaller than the diameter r2 of the high-pressure electro-pneumatic servo valve 4, and the difference between the diameter r1 of the first damping orifice 8 and the second damping orifice 9 and the diameter r2 of the high-pressure electro-pneumatic servo valve 4 is greater than the set threshold, thereby reducing the influence of the damping orifice on the pressure of the two chambers during control.

[0071] To further enhance the control stiffness of the system, the high-voltage electro-pneumatic position servo system in this embodiment of the invention further includes: a first check valve 3 and a second check valve 5; the first check valve 3 is disposed between the first electromagnetic switch valve 2 and the first damping orifice 8; the second check valve 5 is disposed between the first electromagnetic switch valve 2 and the second damping orifice 9. The first check valve and the second check valve prevent the two chambers A and B of the double-acting cylinder from being connected due to the damping orifice during operation, thereby further enhancing the control stiffness of the system.

[0072] In this embodiment of the invention, the high-pressure electro-pneumatic servo valve 4 is a single-stage slide valve servo valve directly driven by a voice coil motor, and its valve core position is controlled by a closed loop.

[0073] Before the high-voltage electro-pneumatic position servo system in this embodiment of the invention starts working, the first electromagnetic switch valve 2 is opened, and the second electromagnetic switch valve 6 and the third electromagnetic switch valve 7 are closed. The air source 1 pre-charges the A and B chambers of the double-rod double-acting cylinder 10 with air through the first electromagnetic switch valve 2, the first damping orifice 8 and the second damping orifice 9, thereby adjusting the initial pressure of the A and B chambers, improving the control stiffness of the high-voltage electro-pneumatic position servo system and improving the stability of the load position control.

[0074] During operation, when the load position needs to remain unchanged, the high-pressure electro-pneumatic servo valve 4 uses the two chambers of the double-rod double-acting cylinder 10 to charge and discharge air to stabilize the load position. Then, it closes the first solenoid switch valve 2, the second solenoid switch valve 6, and the third solenoid switch valve 7 to lock the load position and reduce the leakage of high-pressure air in the system.

[0075] When the high-voltage electro-pneumatic position servo system is working, the control methods of the intelligent controller 12 include:

[0076] S1. Open the first solenoid valve 2, the second solenoid valve 6, and the third solenoid valve 7; the position sensor 11 detects the actual position of the piston rod of the double-rod double-acting cylinder 10 and generates a position signal x1, which is then transmitted to the intelligent controller 12; simultaneously, the intelligent controller 12 obtains the load position command x through the communication interface. 1d ;

[0077] S2, Intelligent Controller 12 combines the position signal with the load's position command x 1d After comparison, the position error of the piston rod of the double-rod double-acting cylinder 10, also known as the tracking error z1, is obtained, z1 = x1 - x 1d ;

[0078] S3. Use the constructed state observer without velocity feedback to observe the external disturbance x of the system. e The estimated external disturbance is obtained by making an estimate. And utilize the estimated external disturbances And the tracking error z1 of the piston rod of the double-rod double-acting cylinder 10 is calculated to determine the position control signal u of the valve core of the high-pressure electro-pneumatic servo valve 4;

[0079] S4. Use position control signal u to control the position of the valve core of high-pressure electro-pneumatic servo valve 4, thereby controlling the pressure in the two chambers of double rod double-acting cylinder 10 to control the position of the load.

[0080] Specifically, in S3, a constructed state observer without velocity feedback is used to monitor external disturbances x in the system. e The estimated external disturbance is obtained by making an estimate. And utilize the estimated external disturbances The tracking error z1 of the piston rod of the double-rod double-acting cylinder 10 is calculated, along with the position control signal u of the valve core of the high-pressure electro-pneumatic servo valve 4, including:

[0081] S31. Establish the state equation of the high-voltage electro-pneumatic position servo system. This state equation includes the external disturbance x. e and parameters θ1 and θ2; where the external disturbance x e The disturbances and unmodeled states of the system are collectively referred to as external disturbances in this embodiment of the invention. The unknown parameters θ1 and θ2 are used to characterize the viscous damping coefficient and the Coulomb friction coefficient, respectively. In other embodiments, the unknown parameters θ1 and θ2 can be estimated by direct adaptive methods. In this embodiment of the invention, the unknown parameters θ1 and θ2 are obtained by a new indirect adaptive estimation method.

[0082] S32. Estimate the unknown parameters θ1 and θ2 in the state equation to obtain the estimated unknown parameters. and The observed error of the piston rod of a double-acting cylinder with two rods is used as an example. and estimated unknown parameters and Using the external disturbance x in the state equation as input, construct a state observer without velocity feedback. e The estimated external disturbance is obtained by making an estimate. Among them, the observation error of the piston rod of the double-rod double-acting cylinder 10 The position signal x1 of the piston rod of the double-bar double-acting cylinder 10 detected by position sensor 11 and the observed value of the constructed state observer without velocity feedback. The difference between them;

[0083] S33, Tracking error z1 of piston rod in double-acting cylinder 10, estimated external disturbance. Unknown parameters and Calculate the position control signal u of the valve core of the high-pressure electro-pneumatic servo valve 4.

[0084] Specifically, in S31, the dynamic equation of the high-voltage electro-pneumatic position servo system is established according to Newton's second law, and the state equation of the system is obtained.

[0085] The dynamic equation of the high-voltage electro-pneumatic position servo system is:

[0086]

[0087] Where m represents the mass of the piston and load, y represents the displacement of the piston (i.e., the position signal x1 of the piston rod of the double-rod double-acting cylinder 10 detected by position sensor 11), P1 and P2 represent the air pressures in chambers A and B, respectively.a Represents the area of ​​the piston. A function representing the direction of friction; B v is the unknown viscous damping coefficient, f is the unknown Coulomb friction coefficient, and d1 represents the unknown external disturbance and unmodeled dynamics.

[0088] In this embodiment of the invention, the dot above the parameter represents the first derivative of the parameter with respect to time, for example, The dot (·) above the parameter a indicates the derivative of parameter a with respect to time; the two dots above the parameter indicate the second derivative of the parameter with respect to time, for example, This represents the second derivative of parameter a with respect to time; that is, Indicates the speed of the piston. This indicates the piston's acceleration; the ^ above the parameter indicates an estimated value of the parameter, for example, This represents the estimated value of parameter a, that is, These are estimates of θ1 and θ2. It is x e The estimated value.

[0089] In formula (1), the differential equations for the gas pressure in cylinder chambers A and B are:

[0090]

[0091] Where k is the adiabatic index of air, R is the ideal gas constant, T1 and T2 are the temperatures of cavity A and cavity B, respectively, V1 and V2 are the initial volumes of cavity A and cavity B, respectively, and Q is the initial volume of cavity A and cavity B. m1 and Q m2 These are the gas mass flow rates entering chamber A and chamber B, respectively.

[0092] The high-pressure electro-pneumatic servo valve in this embodiment of the invention can be considered as a proportional element. The opening degree of the high-pressure electro-pneumatic servo valve is directly proportional to the servo valve control command. Therefore, Q m1 and Q m2 The equation is:

[0093]

[0094] Among them, Q m C is the gas mass flow rate. d A is the flow coefficient at the servo valve orifice. s P is the flow area coefficient of the servo valve orifice, u is the position control information of the valve core of the high-pressure electro-pneumatic servo valve, and P is the flow area coefficient of the servo valve orifice. u P represents the pressure upstream of the valve port of the high-pressure electro-pneumatic servo valve. d The pressure downstream of the high-pressure electro-pneumatic servo valve orifice is T, the temperature of the gas upstream of the orifice is σ. cr This is the critical pressure ratio.

[0095] Rearrange formulas (1)-(3) and select... As the state variables of the system, the state equation of the system is obtained as follows:

[0096]

[0097]

[0098]

[0099] C1 = C d A s P u1 F ψ (P u1 ,P d1 )

[0100] C2 = C d A s P u2 F ψ (P u2 ,P d2 )

[0101] in, It is x = [x1, x2, x3] T The derivative of S(x2) is also known as S(x2). A function representing the direction of friction; P u1 P represents the upstream pressure at the servo valve port when filling or venting chamber A. u2 P represents the downstream pressure at the servo valve port when filling or venting chamber A. d1 P represents the upstream pressure at the servo valve port when filling or venting chamber B. d2 This represents the downstream pressure at the servo valve orifice when filling or venting chamber B; θ1 = B v / m, θ2=f / m, x e =d1 / m is unknown. The unknown parameters θ1 and θ2 are used to characterize the viscous damping coefficient and the Coulomb friction coefficient, respectively. The external disturbance x e Used to characterize external disturbances and unmodeled states of a system.

[0102] Specifically, in S32, based on the system's state equation (4), the state observer without velocity feedback constructed in this invention is as follows:

[0103]

[0104] in, These are estimates of θ1 and θ2. and They are x1, x2 and x e The observed (estimated) values, yes The derivative, yes The derivative, yes The derivative of ω0 > 0 is the designed observer bandwidth; This represents the observation error of the piston rod of the double-acting cylinder 10, that is, the difference between the position signal x1 generated by the position sensor 11 and the observed value of the constructed state observer without velocity feedback. The difference between them

[0105] Specifically, in S32, the present invention estimates the unknown parameters θ1 and θ2 in the state equation by designing an indirect adaptive rate, wherein the adaptive rate of the unknown parameters θ1 and θ2 is...

[0106]

[0107] in, Pick or Γ is a 2×2 diagonal matrix representing the gain of the adaptive rate, which is obtained empirically in this embodiment of the invention. τ is a key parameter in the adaptive law.

[0108]

[0109] Where i takes the value 1 or 2; θ max =[θ 1max ,θ 2max ] T With θ min =[θ 1min ,θ 2min ] T These are the upper and lower bounds for the unknown parameters θ1 and θ2, respectively.

[0110] In this embodiment of the invention, the key parameter τ is designed in the following form, which is an indirect adaptive law;

[0111]

[0112] A function representing the direction of frictional force.

[0113] Specifically, in S33, the tracking error z1 of the piston rod of the double-rod double-acting cylinder 10 and the estimated external disturbance are used. Unknown parameters and The position control signal u of the high-pressure electro-pneumatic servo valve 4 spool is calculated as follows:

[0114]

[0115] Where α2 is the virtual control law for state variable x3, and the formula is:

[0116]

[0117] In the formula, α1 is the virtual control law for the state variable x2, and the formula is:

[0118]

[0119] And z3 = x3 - α2, k1, k2, and k3 are set control parameters; u a u s These are the feedforward compensation term and the robust suppression term, respectively.

[0120] In this embodiment of the invention, the control parameters of the state observer without velocity feedback are: ω0=5000, Γ=diag{100,50}, k1=1200, k2=1000, k3=800.

[0121] In this embodiment of the invention, a system is built in MATLAB / Simulink as follows: Figure 1 The simulation model of the high-pressure pneumatic position servo system shown is illustrated in Table 1.

[0122] Table 1 Simulation parameters of the high-pressure pneumatic position servo system

[0123] <![CDATA[P a ]]> 101325Pa m 10kg <![CDATA[d1]]> 2000sin(10πt) <![CDATA[P s ]]> 25MPa <![CDATA[V1]]> <![CDATA[4.3×10 -5 m 3 ]]> <![CDATA[A s ]]> 0.02 R 287 J / (kg·K) <![CDATA[V2]]> <![CDATA[4.6×10 -4 m 3 ]]> <![CDATA[B v ]]> 500 N·s / m <![CDATA[σ cr ]]> 0.528 k 1.4 f 200N <![CDATA[A a ]]> <![CDATA[0.007m 2 ]]> <![CDATA[C d ]]> 0.7 / /

[0124] In Table 1, P a P represents atmospheric pressure. s This indicates the gas source pressure.

[0125] In this embodiment of the invention, the control objective is:

[0126] Reference signal 1: Step response signal: x 1d =50mm;

[0127] Reference signal 2: Sine response signal: x 1d = [5sin(20πt)+30]mm;

[0128] Simulation experiments were conducted using the indirect adaptive controller without output feedback described in this invention. Figures 2-5 The control effect of the method of the present invention on tracking the same reference signal is presented compared with that of commonly used existing algorithms (direct adaptive control algorithm and PID control algorithm).

[0129] In this embodiment of the invention, the control parameters of the existing direct adaptive control algorithm are k1 = 1200, k2 = 1000, k3 = 800, and Γ = diag{100, 50, 100}. The control parameters of the existing PID control algorithm are kp =0.5,k i =0.1,k d =0.003.

[0130] The tracking errors of different control algorithms for reference signal 1 are shown in Table 2; the tracking errors of different control algorithms for reference signal 2 are shown in Table 3.

[0131] Table 2 Comparison of tracking errors of different control methods for step reference signals

[0132]

[0133]

[0134] Table 3 Comparison of tracking errors of different control methods for sinusoidal reference signals

[0135]

[0136] The comparison shows that the method of the present invention has higher tracking accuracy, whether for step reference signals or sinusoidal reference signals.

[0137] The high-pressure electro-pneumatic position servo system of the present invention is a pneumatic position servo system constructed by a high-pressure electro-pneumatic servo valve 4 and three electromagnetic switching valves 2. The high-pressure electro-pneumatic servo valve 4 is used as the servo amplification element of the system to precisely control the air flow into the two chambers of the cylinder. The electromagnetic switching valves are used to control the opening and closing of the air path, which can improve the response speed and control accuracy of the system.

[0138] Before the system moves, the two chambers of the double-rod double-acting cylinder are pre-charged with damping holes, which increases the stiffness of the high-voltage electro-pneumatic position servo system and further improves the stability of system control.

[0139] To prevent the damping orifice from connecting the A and B chambers of the double-acting cylinder, a check valve is installed before the damping orifice, which further improves the reliability of the system.

[0140] The high-voltage electro-pneumatic position servo system control method of the present invention uses a two-stage closed-loop control between the high-voltage electro-pneumatic servo valve 4 and the double-rod double-acting cylinder 10, which can achieve precise control of the load position.

[0141] The high-voltage electro-pneumatic position servo system control method of the present invention addresses the external disturbance x in the system state equation. e During estimation, the constructed state observer without velocity feedback outputs no velocity feedback, allowing for direct and simultaneous estimation of the external disturbance x. e And the state variable x2 representing velocity, there is no external disturbance x that affects the measurement noise introduced during velocity measurement. eThe accuracy of the estimation can improve the precision of control.

[0142] In the high-voltage electro-pneumatic position servo system control method of this invention, when estimating the unknown parameters in the state equation, the key parameter τ in the adaptive law is not related to the system's state error, but is directly driven by the errors of the unknown parameters θ1 and θ2. As long as errors exist in the unknown parameters θ1 and θ2, these errors can be estimated until their true values ​​are obtained. Therefore, this indirect adaptive law designed in this invention can accurately estimate the unknown parameters θ1 and θ2, further improving the controller's control accuracy. The unknown parameters θ1 and θ2 also serve as one of the inputs to a state observer without velocity feedback. Improving the estimation accuracy of the unknown parameters θ1 and θ2 can further improve the observer's accuracy in observing system disturbances, thereby achieving high-precision control of the system.

[0143] In summary, compared to existing control methods, the indirect adaptive rate designed in this invention can improve the estimation accuracy of unknown system parameters, and the designed extended state observer without velocity feedback can avoid the impact of velocity measurement noise on system control performance. Since the uncertain parameters of the system are accurately estimated by the indirect adaptive rate, the extended state observer without velocity feedback can effectively observe system disturbances, achieving high-precision control of the system.

[0144] The present invention also provides an intelligent controller, which includes a computer-readable storage medium and a processor; the computer-readable storage medium is used to store executable instructions; the processor is used to read the executable instructions stored in the computer-readable storage medium and execute the control method of the high-voltage electro-pneumatic position servo system in the above embodiments.

[0145] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A control method for a high-voltage electro-pneumatic position servo system, characterized in that, The high-pressure electro-pneumatic position servo system includes: a high-pressure electro-pneumatic servo valve (4), a first electromagnetic switch valve (2), a second electromagnetic switch valve (6), a third electromagnetic switch valve (7), a double-acting cylinder (10), and a position sensor (11); the first electromagnetic switch valve (2) is connected to the high-pressure electro-pneumatic servo valve (4), and the first electromagnetic switch valve (2) is also connected to a gas source; one working port of the high-pressure electro-pneumatic servo valve (4) is connected to one chamber of the double-acting cylinder (10) through the second electromagnetic switch valve (6), and the other working port of the high-pressure electro-pneumatic servo valve (4) is connected to the other chamber of the double-acting cylinder (10) through the third electromagnetic switch valve (7); one end of the piston rod of the double-acting cylinder (10) is used to connect to the load, and the other end is used to abut against the position sensor (11); the control method includes: S1. Open the first solenoid valve (2), the second solenoid valve (6), and the third solenoid valve (7), and obtain the position signal of the piston rod of the double-rod double-acting cylinder (10). and load location instructions ; S2, transfer the position signal Position command of the load After comparison, the tracking error of the piston rod of the double-rod double-acting cylinder (10) was obtained. ; S3. Use the constructed state observer without velocity feedback to observe external disturbances to the system. Make an estimate and utilize the estimated external disturbance. and the tracking error Calculate the position control signal u of the valve core of the high-pressure electro-pneumatic servo valve (4); the state observer is: in, The state of the state observer; Indicates parameters The derivative with respect to time, Indicates parameters The estimated value, , m is the mass of the piston rod and the load, P1 and P2 are the air pressures in the two chambers of the double-rod double-acting cylinder (10), and A a Let be the area of ​​the piston. It is a function of the direction of friction. and They are used to characterize the viscous damping coefficient and the Coulomb friction coefficient, respectively. It is the bandwidth of the state observer. For observation error, ; S4. Use the position control signal u to control the position of the valve core of the high-pressure electric-pneumatic servo valve (4), thereby controlling the load position; S3 also includes: parameters and Estimate the parameters and The adaptive rate for estimation is: in, Pick or ; Choose 1 or 2. For parameters and The upper realm, For parameters and The lower bound; Gain for adaptive rate; The key parameter is expressed as follows: ； In S3, the estimated external disturbance is used. and the tracking error The calculated position control signal u of the high-pressure electro-pneumatic servo valve (4) is: Where k is the adiabatic index of air, and R is the ideal gas constant. and V1 and V2 are the temperatures of the two chambers, respectively, and V1 and V2 are the initial volumes of the two chambers, respectively. and These are the coefficients corresponding to the two cavities. This is a robust suppression term; State variables The virtual control law is given by the following formula: In the formula, State variables Virtual control law, Indicates the location of the load. The second derivative of , where k2 is a preset control parameter.

2. The control method according to claim 1, characterized in that, The high-pressure electro-pneumatic position servo system further includes: a first damping hole (8) and a second damping hole (9) respectively disposed on the two chambers of the double-rod double-acting cylinder (10); wherein, the diameter r1 of the first damping hole (8) and the second damping hole (9) is smaller than the diameter r2 of the high-pressure electro-pneumatic servo valve (4), and the difference between r1 and r2 is greater than a set threshold; the first electromagnetic switch valve (2) is connected to the two chambers of the double-rod double-acting cylinder (10) respectively through the first damping hole (8) and the second damping hole (9).

3. The control method according to claim 2, characterized in that, The high-voltage electro-pneumatic position servo system also includes: a first check valve (3) and a second check valve (5); The first check valve (3) is disposed between the first electromagnetic switch valve (2) and the first damping orifice (8); the second check valve (5) is disposed between the first electromagnetic switch valve (2) and the second damping orifice (9).

4. The control method according to any one of claims 1-3, characterized in that, The high-pressure electro-pneumatic servo valve (4) is a single-stage slide valve servo valve directly driven by a voice coil motor, and the valve core position is controlled by a closed loop.

5. The control method according to claim 2, characterized in that, When the high-voltage electro-pneumatic position servo system further includes a first damping hole (8) and a second damping hole (9) respectively disposed on the two chambers of the double-rod double-acting cylinder (10), before S1, it also includes: Control the opening of the first electromagnetic switch valve (2), and close the second electromagnetic switch valve (6) and the third electromagnetic switch valve; The air source pre-charges the two chambers of the double-rod double-acting cylinder (10) through the first electromagnetic switch valve (2), the first damping hole (8) and the second damping hole (9) to adjust the initial pressure of the two chambers.

6. The control method according to claim 3, characterized in that, When the high-voltage electro-pneumatic position servo system further includes a first check valve (3) and a second check valve (5), after S4, it also includes: The high-pressure electro-pneumatic servo valve (4) is controlled to maintain the load position by filling and discharging the two chambers of the double-rod double-acting cylinder (10); Close the first solenoid valve (2), the second solenoid valve (6) and the third solenoid valve (7) to lock the load position.

7. An intelligent controller, characterized in that, Includes computer-readable storage media and processors; The computer-readable storage medium is used to store executable instructions; The processor is configured to read executable instructions stored in the computer-readable storage medium and execute the control method according to any one of claims 1-6.

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