High-precision hydraulic servo control system and fault diagnosis method thereof

Abstract

The invention relates to the technical field of hydraulic servo control systems, and discloses a high-precision hydraulic servo control system and a fault diagnosis method thereof.The hydraulic servo control system comprises a system control module, a hydraulic execution module, a data feedback module, an automatic compensation module and a feedback control module; the system control module is used for receiving and processing an input signal and outputting a control instruction; the hydraulic execution module is used for generating a corresponding hydraulic action according to the control instruction; the data feedback module is used for detecting the actual position and pressure of the hydraulic execution module and transmitting a feedback signal to the automatic compensation module; the automatic compensation module is used for eliminating system errors through a compensation algorithm; the feedback control module is used for comparing the difference between the system output and a set target, generating a deviation signal, and adjusting the input of the system by using the signal, so that the system output is closer to the set target; through the system, the control precision and stability of the hydraulic servo control system can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic servo control systems, and in particular relates to a high-precision hydraulic servo control system and a fault diagnosis method thereof. Background Art

[0002] High-precision control is one of the core requirements of modern industrial automation. With the advancement of science and technology and the development of industry, the control accuracy requirements for hydraulic servo control systems are getting higher and higher. High-precision control systems can execute instructions more accurately, reduce errors, and improve product quality and production efficiency. This is of great significance to improving the competitiveness and market position of the entire industrial production.

[0003] Secondly, hydraulic servo control systems are widely used in various mechanical equipment, such as CNC machine tools, injection molding machines, die-casting machines, etc. These equipment need to accurately control parameters such as force, speed and position during operation to ensure the accuracy and consistency of the workpiece. If the control accuracy is not high, it will lead to problems such as dimensional deviation and shape distortion of the workpiece, seriously affecting product quality.

[0004] In addition, improving the control accuracy of the hydraulic servo control system can also help reduce energy consumption and reduce the failure rate. A high-precision control system can more accurately control the working state of hydraulic components, avoid unnecessary energy waste and component wear, thereby extending the service life of the system and reducing maintenance costs.

[0005] Therefore, improving the control accuracy of hydraulic servo control systems is an important guarantee for meeting the needs of modern industrial automation, ensuring product quality, reducing energy consumption and failure rate, and adapting to the development of intelligent manufacturing and industrial Internet.

[0006] To this end, we propose a high-precision hydraulic servo control system and its fault diagnosis method. Summary of the invention

[0007] The purpose of the present invention is to improve the control accuracy and stability of a hydraulic servo control system. The present application provides a high-precision hydraulic servo control system and a fault diagnosis method thereof.

[0008] The technical solution adopted by the present invention is as follows: A high-precision hydraulic servo control system and a fault diagnosis method thereof, wherein the hydraulic servo control system comprises a system control module, a hydraulic execution module, a data feedback module, an automatic compensation module and a feedback control module; The system control module is used to receive and process input signals and output control instructions; the hydraulic execution module is used to generate corresponding hydraulic actions according to the control instructions; the data feedback module is used to detect the actual position and pressure of the hydraulic execution module and transmit the feedback signal to the automatic compensation module; the automatic compensation module is used to eliminate system errors, such as steady-state errors, through compensation algorithms, and improve the dynamic response performance of the system; the feedback control module is used to compare the difference between the system output and the set target, generate a deviation signal, and use this signal to adjust the system input, so that the system output is closer to the set target.

[0009] In a preferred embodiment of the invention, the system control module includes a control computer, a servo controller and a servo drive.

[0010] In a preferred embodiment of the invention, the hydraulic execution module includes a cylinder, a hydraulic pump and a hydraulic solenoid valve.

[0011] In a preferred embodiment of the invention, the data feedback module includes a position sensor and a pressure sensor.

[0012] In a preferred embodiment of the invention, the compensation algorithm is used to calculate the proportion (P), integration (I) and differentiation (D) of the difference between the system output and the set value to generate the control signal.

[0013] In a preferred embodiment of the invention, the calculation formula of the ratio (P) is (P_{\text{out}} = K_p \cdot e(t)), where (K_p) is the proportional gain and (e(t)) is the current error.

[0014] In a preferred embodiment of the invention, the calculation formula of the integral (I) is ( I_{\text{out}} = K_i \cdot \int_0t e(\tau) , d\tau ), where ( K_i ) is the integral gain, and ( \int_0t e(\tau) , d\tau ) is the integral of the error from 0 to the current time ( t ).

[0015] In a preferred embodiment of the invention, the calculation formula of the differential (D) is ( D_{\text{out}} = K_d \cdot \frac{de(t)}{dt} ), where ( K_d ) is the differential gain, and ( \frac{de(t)}{dt} ) is the derivative of the error (i.e., the rate of change of the error).

[0016] In a preferred embodiment of the invention, the calculation formula of the compensation algorithm is [ \text{PID}{\text{out}}= P{\text{out}} + I_{\text{out}} + D_{\text{out}} = K_p \cdot e(t) + K_i \cdot \int_0t e(\tau) , d\tau + K_d \cdot \frac{de(t)}{dt} ].

[0017] In a preferred embodiment of the invention, a high-precision hydraulic servo control fault diagnosis method is provided: S1: Check the initial status of the system to see if there is any obvious damage to the system components, such as oil leakage, loose wiring, etc. Confirm that the system power supply is stable, the grounding is good, there is no short circuit or leakage, and use a standard signal source to calibrate the sensor to ensure that its output is accurate and reliable; S2: Perform basic parameter setting and verification. According to system characteristics and historical experience, preliminarily set the proportional, integral, and differential parameters of the automatic compensation module controller. In a closed-loop state, let the system perform a simple action cycle, observe and record the system's response curve, such as displacement, speed, and pressure; S3: Observe and analyze the fault phenomenon, record in detail any abnormal phenomena that occur during system operation, such as jitter, lag, overshoot, etc., use data recording and analysis tools to carefully analyze the system response curve and identify the characteristic points that are inconsistent with the normal state; S4: Adjust and optimize the compensation algorithm parameters, adjust the proportional, integral and differential parameters respectively, observe the influence of each parameter change on the system response, increase the proportional coefficient can improve the system response speed, but may cause system instability; reduce the proportional coefficient, the opposite is true; the smaller the integral time constant, the stronger the integral effect, which helps to eliminate static errors, but may cause system overshoot; increase the integral time constant, the weaker the integral effect; the smaller the differential time constant, the more obvious the differential effect, which helps to suppress error changes in advance, but may increase system noise; on the basis of single parameter adjustment, make comprehensive adjustments to seek the best compensation algorithm parameter combination, so that the system can respond to instructions quickly and stably; S5: Perform fault location and troubleshooting. According to the changes in system response during the compensation algorithm parameter adjustment process, combined with the system structure and working principle, analyze and locate the source of the fault. If the proportional parameter adjustment is invalid, it may indicate that there is a problem with the sensor signal transmission or the actuator is sluggish in response; if the integral parameter adjustment is difficult, it may mean that there is continuous external interference or internal leakage in the system; if the differential parameter adjustment causes system oscillation, it may indicate that the system inertia is too large or the controller gain is too high; and take repair measures based on the fault source analysis results.

[0018] S6: Retest and verify the system. After troubleshooting, re-perform closed-loop testing to verify whether the system has resumed normal operation, compare the system performance before and after the fault, evaluate the effect of troubleshooting, and ensure that the system meets the expected accuracy and stability requirements.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. In the present invention, the system control module receives input signals and performs calculations based on feedback signals to control the actions of the hydraulic actuator module and control displacement, speed or force. The data feedback module is used to detect the actual position and pressure of the hydraulic actuator module and transmit the feedback signal to the automatic compensation module. The automatic compensation module is used to eliminate system errors through compensation algorithms, and the feedback control module is used to compare the difference between the system output and the set target to generate a deviation signal, and use this signal to adjust the system input, so that the system output is closer to the set target, thereby improving the control accuracy and stability of the hydraulic servo control system.

[0020] 2. In the present invention, in the high-precision hydraulic servo control system, it is often difficult to establish an accurate mathematical model due to the high complexity and strong nonlinearity of the system. However, by utilizing the compensation algorithm, it is only necessary to adjust the three parameters of proportion, integration and differentiation to achieve high control accuracy and stability of the system.

[0021] 3. In the present invention, the parameters of the compensation algorithm are easy to adjust and do not require complicated programming and debugging processes. This enables technicians to quickly get started and locate the problem quickly when diagnosing system failures, thereby improving the efficiency of fault diagnosis and improving the control accuracy and stability of the hydraulic servo control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of the fault diagnosis method in the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The following will be combined Figure 1 A high-precision hydraulic servo control system and a fault diagnosis method thereof according to an embodiment of the present invention are described in detail. Example

[0025] Reference Figure 1 , a high-precision hydraulic servo control system and a fault diagnosis method thereof, the hydraulic servo control system includes a system control module, a hydraulic execution module, a data feedback module, an automatic compensation module and a feedback control module; the system control module includes a control computer, a servo controller and a servo driver, the hydraulic execution module includes a cylinder, a hydraulic pump and a hydraulic solenoid valve, the data feedback module includes a position sensor and a pressure sensor, the system control module is used to receive and process input signals and output control instructions; the hydraulic execution module is used to generate corresponding hydraulic actions according to the control instructions; the data feedback module is used to detect the actual position and pressure of the hydraulic execution module, and transmit the feedback signal to the automatic compensation module; the automatic compensation module is used to eliminate system errors, such as steady-state errors, through compensation algorithms, and improve the dynamics of the system Response performance; the feedback control module is used to compare the difference between the system output and the set target, generate a deviation signal, and use this signal to adjust the system input, so that the system output is closer to the set target; specifically, the system control module receives the input signal and performs calculations based on the feedback signal to control the action of the hydraulic actuator module to control the displacement, speed or force, and the data feedback module is used to detect the actual position and pressure of the hydraulic actuator module, and transmit the feedback signal to the automatic compensation module, the automatic compensation module is used to eliminate the system error through the compensation algorithm, and use the feedback control module to compare the difference between the system output and the set target, generate a deviation signal, and use this signal to adjust the system input, so that the system output is closer to the set target, thereby improving the control accuracy and stability of the hydraulic servo control system.

[0026] Reference Figure 1, the compensation algorithm is used to calculate the proportion (P), integral (I) and differential (D) of the difference between the system output and the set value to generate a control signal, the proportion (P) is calculated by ( P_{\text{out}} = K_p \cdot e(t) ), where ( K_p ) is the proportional gain and ( e(t) ) is the current error; the integral (I) is calculated by ( I_{\text{out}} = K_i \cdot \int_0t e(\tau) , d\tau ), where ( K_i ) is the integral gain and ( \int_0t e(\tau) , d\tau ) is the integral of the error from 0 to the current time ( t ); the differential (D) is calculated by ( D_{\text{out}} = K_d \cdot \frac{de(t)}{dt} ), where ( K_d ) is the differential gain, ( \frac{de(t)}{dt} ) is the derivative of the error (i.e., the rate of change of the error); the calculation formula of the compensation algorithm is [ \text{PID}{\text{out}} = P{\text{out}} + I_{\text{out}} + D_{\text{out}} = K_p \cdot e(t) + K_i \cdot \int_0t e(\tau) , d\tau + K_d \cdot \frac{de(t)}{dt} ]; specifically, in a high-precision hydraulic servo control system, it is often difficult to establish an accurate mathematical model due to the high complexity and strong nonlinearity of the system. By using the compensation algorithm, it is only necessary to adjust the three parameters of proportion, integration and differentiation to achieve high control accuracy and stability of the system.

[0027] Reference Figure 1, a high-precision hydraulic servo control fault diagnosis method, system initial status check, check whether the system components have obvious damage, such as oil leakage, loose wiring, etc., confirm that the system power supply is stable, the grounding is good, there is no short circuit or leakage, use a standard signal source to calibrate the sensor to ensure that its output is accurate and reliable; perform basic parameter setting and calibration, and preliminarily set the proportional, integral, and differential parameters of the automatic compensation module controller according to system characteristics and historical experience. In a closed-loop state, let the system perform a simple action cycle, observe and record the system's response curve, such as displacement, speed, and pressure; observe and analyze fault phenomena, and record in detail any abnormal phenomena that occur during system operation, such as jitter, lag, overshoot, etc. Use data recording and analysis tools to carefully analyze the system response curve and identify feature points that do not match the normal state; adjust and optimize the compensation algorithm parameters, adjust the proportional, integral, and differential parameters respectively, observe the impact of each parameter change on the system response, and increase Adding a proportional coefficient can increase the system response speed, but may cause system instability; reducing the proportional coefficient has the opposite effect; the smaller the integral time constant, the stronger the integral effect, which helps to eliminate static errors, but may cause system overshoot; increasing the integral time constant weakens the integral effect; the smaller the differential time constant, the more obvious the differential effect, which helps to suppress error changes in advance, but may increase system noise; on the basis of single parameter adjustment, comprehensive adjustments are made to seek the best compensation algorithm parameter combination so that the system can respond to instructions quickly and stably; specifically, the compensation algorithm is simple and easy to use, and easy for engineering and technical personnel to master. By adjusting the three parameters of proportion, integration, and differentiation, it is possible to maintain a high control accuracy and stability for the system. The parameters of the compensation algorithm are easy to adjust and do not require complicated programming and debugging processes. This allows technicians to quickly get started and quickly locate the problem when diagnosing system failures, thereby improving the efficiency of fault diagnosis and thus improving the control accuracy and stability of the hydraulic servo control system.

[0028] Reference Figure 1, locate and troubleshoot the fault. According to the changes in the system response during the compensation algorithm parameter adjustment process, combined with the system structure and working principle, analyze and locate the fault source. If the proportional parameter adjustment is invalid, it may indicate that there is a problem with the sensor signal transmission or the actuator is slow to respond; if the integral parameter adjustment is difficult, it may mean that there is continuous external interference or internal leakage in the system; if the differential parameter adjustment causes system oscillation, it may indicate that the system inertia is too large or the controller gain is too high; and take repair measures based on the fault source analysis results. Retest and verify the system. After troubleshooting, re-perform closed-loop testing to verify whether the system has resumed normal operation, compare the system performance before and after the fault, evaluate the effect of troubleshooting, and ensure that the system meets the expected accuracy and stability requirements; specifically, the compensation algorithm has good dynamic performance. The dynamic performance of the system often directly affects the quality and production efficiency of the product, and the compensation algorithm can contain the main information of the past, present, and future in the dynamic control process. By reasonably configuring the parameters, a fast, smooth, and accurate dynamic control process can be achieved, thereby improving the control accuracy and stability of the hydraulic servo control system.

[0029] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0030] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-precision hydraulic servo control system, characterized in that: The hydraulic servo control system includes a system control module, a hydraulic execution module, a data feedback module, an automatic compensation module and a feedback control module; The system control module is used to receive and process input signals and output control instructions; the hydraulic execution module is used to generate corresponding hydraulic actions according to the control instructions; the data feedback module is used to detect the actual position and pressure of the hydraulic execution module and transmit the feedback signal to the automatic compensation module; the automatic compensation module is used to eliminate system errors, such as steady-state errors, through compensation algorithms, and improve the dynamic response performance of the system; the feedback control module is used to compare the difference between the system output and the set target, generate a deviation signal, and use this signal to adjust the system input, so that the system output is closer to the set target.

2. A high-precision hydraulic servo control system according to claim 1, characterized in that: The system control module includes a control computer, a servo controller and a servo driver.

3. A high-precision hydraulic servo control system according to claim 1, characterized in that: The hydraulic execution module includes an oil cylinder, a hydraulic pump and a hydraulic solenoid valve.

4. A high-precision hydraulic servo control system according to claim 1, characterized in that: The data feedback module includes a position sensor and a pressure sensor.

5. A high-precision hydraulic servo control system according to claim 1, characterized in that: The compensation algorithm is used to calculate the proportional (P), integral (I) and derivative (D) of the difference between the system output and the set point to generate a control signal.

6. A high-precision hydraulic servo control system according to claim 1, characterized in that: The calculation formula of the proportion (P) is ( P_{\text{out}} = K_p \cdot e(t) ), where ( K_p ) is the proportional gain and ( e(t) ) is the current error.

7. A high-precision hydraulic servo control system according to claim 1, characterized in that: The calculation formula of the integral (I) is ( I_{\text{out}} = K_i \cdot \int_0t e(\tau) , d\tau ), where ( K_i ) is the integral gain, and ( \int_0t e(\tau) , d\tau ) is the integral of the error from 0 to the current time ( t ).

8. A high-precision hydraulic servo control system according to claim 1, characterized in that: The calculation formula of the differential (D) is ( D_{\text{out}} = K_d \cdot \frac{de(t)}{dt} ), where ( K_d ) is the differential gain and ( \frac{de(t)}{dt} ) is the derivative of the error (i.e., the rate of change of the error).

9. A high-precision hydraulic servo control system according to claim 1, characterized in that: The calculation formula of the compensation algorithm is [ \text{PID}{\text{out}} = P{\text{out}} + I_{\text{out}} + D_{\text{out}} = K_p \cdot e(t) + K_i \cdot \int_0t e(\tau) , d\tau + K_d \cdot \frac{de(t)}{dt} ].

10. A high-precision hydraulic servo control fault diagnosis method, characterized in that The device according to any one of claims 1 to 9 is used: S1: Check the initial status of the system to see if there is any obvious damage to the system components, such as oil leakage, loose wiring, etc. Confirm that the system power supply is stable, the grounding is good, there is no short circuit or leakage, and use a standard signal source to calibrate the sensor to ensure that its output is accurate and reliable; S2: Perform basic parameter setting and verification. According to system characteristics and historical experience, preliminarily set the proportional, integral, and differential parameters of the automatic compensation module controller. In a closed-loop state, let the system perform a simple action cycle, observe and record the system's response curve, such as displacement, speed, and pressure; S3: Observe and analyze the fault phenomenon, record in detail any abnormal phenomena that occur during system operation, such as jitter, lag, overshoot, etc., use data recording and analysis tools to carefully analyze the system response curve and identify the characteristic points that are inconsistent with the normal state; S4: Adjust and optimize the compensation algorithm parameters, adjust the proportional, integral and differential parameters respectively, observe the influence of each parameter change on the system response, increase the proportional coefficient can improve the system response speed, but may cause system instability; reduce the proportional coefficient, the opposite is true; the smaller the integral time constant, the stronger the integral effect, which helps to eliminate static errors, but may cause system overshoot; increase the integral time constant, the weaker the integral effect; the smaller the differential time constant, the more obvious the differential effect, which helps to suppress error changes in advance, but may increase system noise; on the basis of single parameter adjustment, make comprehensive adjustments to seek the best compensation algorithm parameter combination, so that the system can respond to instructions quickly and stably; S5: Fault location and troubleshooting. According to the changes in system response during the compensation algorithm parameter adjustment process, combined with the system structure and working principle, analyze and locate the fault source. If the proportional parameter adjustment is invalid, it may indicate that there is a problem with the sensor signal transmission or the actuator is slow to respond; if the integral parameter adjustment is difficult, it may mean that there is continuous external interference or internal leakage in the system; if the differential parameter adjustment causes system oscillation, it may indicate that the system inertia is too large or the controller gain is too high; and take repair measures according to the fault source analysis results; S6: Retest and verify the system. After troubleshooting, re-perform closed-loop testing to verify whether the system has resumed normal operation, compare the system performance before and after the fault, evaluate the effect of troubleshooting, and ensure that the system meets the expected accuracy and stability requirements.

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