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CN-122014710-A - Hydraulic valve intelligent shaft control method based on preset time output performance

CN122014710ACN 122014710 ACN122014710 ACN 122014710ACN-122014710-A

Abstract

The invention discloses an intelligent shaft control method of a hydraulic valve based on preset time output performance, which innovatively introduces a safety function of the preset time performance, integrates a neural network real-time learning technology and a dynamic surface control idea, and designs an intelligent shaft controller based on the preset time output performance. Aiming at the hydraulic valve position shaft control problem, the invention can realize the preset time control of the transient performance and the steady state performance of the system output, ensure the safe and reliable operation of the system, also can utilize the neural network to learn the unknown dynamics of the system in real time, realize the high-precision motion control performance, can avoid the differential explosion problem in the traditional backstepping control of the hydraulic valve shaft control system, and reduce the influence of measurement noise on the control precision.

Inventors

  • YANG XIAOWEI
  • YAO JIANYONG
  • YU XIAOCHUAN

Assignees

  • 南京理工大学

Dates

Publication Date
20260512
Application Date
20260414

Claims (9)

  1. 1. The intelligent shaft control method of the hydraulic valve based on the preset time output performance is characterized by comprising the following steps of: step1, establishing a mathematical model of a hydraulic valve position shaft control system: , Wherein, the Indicating the mass of the load and, Indicating the displacement of the piston rod of the hydraulic cylinder, Indicating the speed of the hydraulic cylinder piston rod, Indicating the acceleration of the piston rod of the hydraulic cylinder, Represents the effective acting area of a piston of the hydraulic cylinder, P 1 represents the oil pressure of an oil inlet cavity of the hydraulic cylinder, P 2 represents the oil pressure of an oil outlet cavity of the hydraulic cylinder, Indicating the frictional forces to which the load is subjected, Representing system mechanical unmodeled interference, t representing time; Turning to step 2; step 2, designing an intelligent shaft controller based on preset time output performance based on a mathematical model of a hydraulic valve position shaft control system: step 2-1, definition error , wherein, Representing the tracking error of the system, Is an instruction that the system desires to track a location, Representing a predetermined time performance safety function, in order to facilitate the system state under the driving of a designed controller Tracking desired position instructions as accurately as possible And let Always satisfy To ensure tracking error Trend toward 0; Wherein the preset time performance safety function The definition is as follows: (10), Wherein, the Which represents a constant positive constant value, and, Which represents a constant positive constant value, and, Which represents a constant positive constant value, and, Which represents a constant positive constant value, and, The function of the cotangent is represented, Representing the circumference ratio; Step 2-2, definition error , wherein, Representation of Is included in the filtered signal of (a), Representation of To ensure tracking error Trend toward 0, need to guarantee errors Trend toward 0; Step 2-3, defining errors , wherein, Representation of Is included in the filtered signal of (a), Representation of To ensure errors Trend toward 0, need to guarantee errors Trend toward 0; , Wherein the gain is , Representing the compensation term based on the model, The robust term is represented as such, A linear robust term is represented and, A non-linear robust term is represented, Is expressed as a constant positive function and satisfies , wherein, The integral variable is represented by a value of the integral variable, Representing constant positive constant, unknown dynamics of the system Upper bound of (2) ; 、 、 All of which represent intermediate variables such as, Representing a nonlinear filter; 、 All represent errors; Turning to step 3; And step 3, performing intelligent shaft controller stability demonstration based on preset time output performance by applying a Lyapunov stability theory to obtain a result of asymptotically stable system tracking error.
  2. 2. The intelligent hydraulic valve shaft control method based on preset time output performance according to claim 1, wherein in step 1, a mathematical model of a hydraulic valve position shaft control system is built, specifically as follows: The hydraulic valve position shaft control system is applied to linear motion of large-scale industrial heavy-duty mechanical equipment, wherein a load is fixedly connected with a piston rod on a hydraulic cylinder, and the hydraulic valve controls the piston rod on the hydraulic cylinder to move so as to drive the load to move, and a mathematical model of the hydraulic valve position shaft control system is obtained according to dynamic characteristics of the load, the hydraulic cylinder and the electro-hydraulic valve; and step 1-2, defining state variables for conveniently designing a controller, and converting a mathematical model of the hydraulic valve position shaft control system into a state space equation.
  3. 3. The intelligent hydraulic valve shaft control method based on the preset time output performance according to claim 2, wherein the hydraulic valve position shaft control system in step 1-1 is applied to linear motion of large industrial heavy-duty mechanical equipment, wherein a load is fixedly connected with a piston rod on a hydraulic cylinder, the hydraulic valve controls the piston rod on the hydraulic cylinder to move so as to drive the load to move, and a mathematical model of the hydraulic valve position shaft control system is obtained according to the dynamic characteristics of the load, the hydraulic cylinder and the hydraulic valve, and is specifically as follows: According to Newton's second law, the force balance equation of the hydraulic valve position axis control system is: (1), In the formula (1), the components are as follows, Indicating the mass of the load and, Indicating the displacement of the piston rod of the hydraulic cylinder, Indicating the speed of the hydraulic cylinder piston rod, Indicating the acceleration of the piston rod of the hydraulic cylinder, Represents the effective acting area of a piston of the hydraulic cylinder, P 1 represents the oil pressure of an oil inlet cavity of the hydraulic cylinder, P 2 represents the oil pressure of an oil outlet cavity of the hydraulic cylinder, Indicating the frictional forces to which the load is subjected, Representing system mechanical unmodeled interference, t representing time; then formula (1) is rewritten as: (2), in the hydraulic valve position shaft control system, the external leakage of oil in the oil cylinder is ignored, and then the pressure dynamic equation is as follows: (3), in the formula (3), the amino acid sequence of the compound, The effective elastic modulus of the oil liquid is shown, Indicating leakage coefficient in hydraulic cylinder, oil pressure difference between oil inlet and outlet cavities at two sides of oil cylinder Control volume of oil inlet chamber Control volume of oil outlet chamber V 01 represents the initial volume of the oil inlet chamber, V 02 represents the initial volume of the oil chamber, The flow rate of the oil inlet cavity is represented, The flow rate of the oil chamber is shown, Representation of Is a non-modeling disturbance of (1), Representation of Is a non-modeling disturbance of (1), Representation of Is used as a first derivative of (a), Representation of Is the first derivative of (a); 、 The following relation is respectively formed with the valve core displacement x v of the hydraulic valve: (4), Wherein the hydraulic valve system comprises , Indicating the flow coefficient of the hydraulic valve, Represents the area gradient of the valve core of the hydraulic valve, Indicating the density of the oil liquid, The pressure of the oil supplied is indicated, The oil return pressure is indicated as the oil return pressure, Representing intermediate variables Is defined as: (5), Neglecting the hydraulic valve spool dynamics, assuming that the control input u to the spool and spool displacement x v are proportional, i.e. satisfy x v = k i u, where k i represents the voltage-spool displacement gain factor, equation (4) is rewritten as: (6), formula (6), intermediate variable Intermediate variables Intermediate variables 。
  4. 4. The intelligent shaft control method of the hydraulic valve based on the preset time output performance according to claim 3, wherein in step 1-2, in order to design a controller conveniently, a state variable is defined, and the obtained mathematical model of the shaft control system of the hydraulic valve position is converted into a state space equation, specifically as follows: Defining a state variable: wherein the intermediate variable Intermediate variables Intermediate variables Then the equation (2) is converted into a state space equation: (7), (7), Representation of Is used as a first derivative of (a), Representation of Is used as a first derivative of (a), Representation of First derivative of (2), system unknown dynamics Intermediate variables Intermediate variables Intermediate variables Unknown dynamics of system T represents the transpose.
  5. 5. The intelligent shaft control method of a hydraulic valve based on preset time output performance according to claim 4, wherein in step 1, in order to facilitate designing a controller, the following assumptions are made: suppose 1 that the system expects tracking position instructions Is continuous in second order, and the system expects position command, speed command and acceleration command to be all bounded; Suppose 2. Unknown dynamics of the system And (3) with The method meets the following conditions: (8), (8), And Are all unknown positive constants; And (2) switching to step 2.
  6. 6. The intelligent hydraulic valve shaft control method based on the preset time output performance according to claim 5, wherein in step 2-1, an error is defined , wherein, Representing the tracking error of the system, Is an instruction that the system desires to track a location, Representing a predetermined time performance safety function, in order to facilitate the system state under the driving of a designed controller Tracking desired position instructions as accurately as possible And let Always satisfy To ensure tracking error Trend toward 0, specifically as follows: Tracking error The preset range is satisfied: (9), in the formula (9), the time performance safety function is preset The definition is as follows: (10), Wherein, the Which represents a constant positive constant value, and, Which represents a constant positive constant value, and, Which represents a constant positive constant value, and, Which represents a constant positive constant value, and, The function of the cotangent is represented, Representing the circumference ratio; To facilitate the design of the controller, the following nonlinear filter is designed: (11), Filter gain (11) , Is the filtering error of (a) , Is expressed as a constant positive function and satisfies , wherein, The integral variable is represented by a value of the integral variable, Which represents a constant positive constant value, and, Representation of Is used as a first derivative of (a), Representation of Is used as a first derivative of (a), Upper bound of (2) ; For tracking error And (5) deriving to obtain: (12), Wherein, the Representing the error; Representation of Is the first derivative of (a); Representation of Is the first derivative of (a); representing a preset time performance safety function Is the first derivative of (a); selecting Lyapunov function Wherein Representing a logarithmic function, the availability is: (13), designing virtual controls The method comprises the following steps: (14), Gain (14) Then (15)。
  7. 7. The intelligent hydraulic valve shaft control method based on the preset time output performance according to claim 6, wherein in step 2-2, an error is defined , wherein, Representation of Is included in the filtered signal of (a), Representation of To ensure tracking error Trend toward 0, need to guarantee errors Trend toward 0, specifically as follows: The following nonlinear filter is designed: (16), Filter gain (16) , Is the filtering error of (a) , Is expressed as a constant positive function and satisfies , wherein, The integral variable is represented by a value of the integral variable, Which represents a constant positive constant value, and, Representation of Is used as a first derivative of (a), Representation of Is used as a first derivative of (a), Upper bound of (2) To (3) pair And (3) deriving: (17), selecting Lyapunov function The method can obtain: (18), designing virtual controls The method comprises the following steps: (19), Gain (19) , Representing the compensation term based on the model, The robust term is represented as such, A linear robust term is represented and, A non-linear robust term is represented, Is expressed as a constant positive function and satisfies , wherein, The integral variable is represented by a value of the integral variable, Which represents a constant positive constant value, and, Upper bound of (2) ; Representation of Is used for the estimation of the (c), The specific form of (2) is as follows: (20), (20), Representation of Is used for the estimation of the (c), The weight value of the neural network is represented, Representing the activation function of the neural network, An input representing a neural network; the weighting update law of the neural network is designed as: (21), (21), Representation of Is used as a first derivative of (a), Representing a weight gain matrix of the neural network, Representing a discontinuous mapping function; substituting formula (19) into formula (18) yields: (22), Neural network weights (22) Is of the estimation error of (2) , Representing the approximation error of the neural network.
  8. 8. The intelligent hydraulic valve shaft control method based on the preset time output performance according to claim 7, wherein in the step 2-3, an error is defined , wherein, Representation of Is included in the filtered signal of (a), Representation of To ensure errors Trend toward 0, need to guarantee errors Trend toward 0, specifically as follows: For a pair of And (3) deriving: (23), selecting Lyapunov function Obtaining: (24), according to equation (24), the control input of the spool, i.e., the intelligent shaft controller u based on the preset time output performance, is: (25), Gain (25) , Representing the compensation term based on the model, The robust term is represented as such, A linear robust term is represented and, A non-linear robust term is represented, Is expressed as a constant positive function and satisfies , wherein, The integral variable is represented by a value of the integral variable, Which represents a constant positive constant value, and, Upper bound of (2) ; Substituting formula (25) into formula (24): (26), and (3) switching to step 3.
  9. 9. The intelligent shaft control method of the hydraulic valve based on the preset time output performance according to claim 8, wherein the intelligent shaft controller stability demonstration based on the preset time output performance by using the lyapunov stability theory in step 3 obtains a result of asymptotically stabilizing a system tracking error, and the method is specifically as follows: the lyapunov function is defined as follows: (27), and performing stability demonstration by using a Lyapunov stability theory to obtain a result of asymptotically stable system tracking error.

Description

Hydraulic valve intelligent shaft control method based on preset time output performance Technical Field The invention relates to the technical field of electromechanical servo control, in particular to an intelligent hydraulic valve shaft control method (PTOPIAC) based on preset time output performance. Background The hydraulic valve shaft control system has important positions in the fields of robots, heavy machinery, high-performance loading test equipment and the like by virtue of the characteristics of high power density, high force/torque output, quick dynamic response and the like. The hydraulic valve gating system is a typical nonlinear system, which contains many nonlinear characteristics and modeling uncertainties. The nonlinear characteristics comprise input nonlinearity such as hysteresis, saturation and the like, flow pressure nonlinearity of a proportional servo valve, friction nonlinearity and the like, and the modeling uncertainty comprises parameter uncertainty and uncertainty nonlinearity, wherein the parameter uncertainty mainly comprises load quality, viscous friction coefficient of an actuator, leakage coefficient, servo valve flow gain, hydraulic oil elastic modulus and the like, and the uncertainty nonlinearity mainly comprises unmodeled friction dynamics, system high-order dynamics, external interference, unmodeled leakage and the like. When the hydraulic valve control system is developed to high precision and high frequency response, the nonlinear characteristic of the system has more remarkable influence on the system performance, and the controller designed by the nominal model of the system is unstable or reduced in order due to the existence of modeling uncertainty, so that the nonlinear characteristic and the modeling uncertainty of the hydraulic valve control system are important factors for limiting the improvement of the system performance. With the continuous progress of the technical level in the industrial and national defense fields, the conventional controller based on the traditional linear theory design cannot meet the high performance requirement of the system, so that a more advanced nonlinear control strategy must be researched aiming at the nonlinear characteristics in the hydraulic valve control system. In response to the problem of non-linear control of hydraulic valve control systems, many methods have been proposed in succession. The adaptive control method is very effective in treating the problem of parameter uncertainty, can obtain the steady-state performance of asymptotically tracking, but is not attractive in treating the uncertainty nonlinearity such as external load interference, and the like, and can lead to system instability when the uncertainty nonlinearity is overlarge, and the actual hydraulic valve control system has uncertainty nonlinearity, so the adaptive control method cannot obtain the high-precision control performance in practical application, and as a robust control method, the classical sliding mode control can effectively treat any bounded modeling uncertainty and obtain the steady-state performance of asymptotically tracking, but the discontinuous controller designed by the classical sliding mode control easily causes the flutter problem of a sliding mode surface, so the tracking performance of a system is deteriorated, and in order to solve the problems of the parameter uncertainty and the uncertainty nonlinearity, the adaptive robust control method can lead to the system to obtain the determined and steady-state performance under the condition that two modeling uncertainties exist simultaneously, and if the high-precision tracking performance is required to be obtained, the tracking error is reduced by increasing the feedback gain, and the steady-state performance is often caused by the fact that the system is subjected to the high-state gain is degraded due to the existence of measurement noise, and the high-quality control is caused by the fact that the steady-state performance is frequently input. Disclosure of Invention The invention aims to provide a hydraulic valve position shaft control method with limited system output performance, active learning compensation, strong anti-interference capability and high tracking performance, which can realize the preset time control of the system output transient performance and steady state performance, ensure the safe and reliable operation of the system, learn the unknown dynamics of the system in real time by utilizing a neural network, realize the high-precision motion control performance, avoid the problem of differential explosion in the traditional backstepping control of the hydraulic valve shaft control system and reduce the influence of measurement noise on the control precision. The technical scheme for realizing the purpose of the invention is that the intelligent shaft control method of the hydraulic valve based on the preset time output performance comprises the following st