CN-121657565-B - Hydraulic engineering cofferdam gate control system based on PLC

CN121657565BCN 121657565 BCN121657565 BCN 121657565BCN-121657565-B

Abstract

The application relates to the technical field of water conservancy control, and discloses a water conservancy project cofferdam gate control system based on a PLC. The controller is internally provided with a discrete state observation module, a disturbance characteristic identification module, a virtual axis parameter scheduling module and a control law synthesis module. The system comprises a discrete state observation module, a disturbance characteristic identification module, a virtual axis parameter scheduling module, a control law synthesis module and a feedforward compensation module, wherein the discrete state observation module reconstructs a system state and estimates total disturbance, the disturbance characteristic identification module judges normal, blockage or turbulence working conditions according to disturbance characteristics, the virtual axis parameter scheduling module adjusts virtual rigidity and damping coefficients in real time according to the working conditions or executes an asymmetric auxiliary escaping strategy, and the control law synthesis module combines state feedback and feedforward compensation to generate control voltage. According to the application, through multi-mode parameter scheduling, the interference of water flow impact and nonlinear friction is effectively overcome, the decoupling under turbulent flow working conditions and the flexible protection and auxiliary escape under blocking working conditions are realized, and the synchronization precision and safety of gate control are improved.

Inventors

CHEN YUN
CHEN LIANG
LI GUOXIN
Wu Juncao
LU YANG

Assignees

江苏省交通工程集团有限公司

Dates

Publication Date: 20260508
Application Date: 20260205

Claims (10)

1. Hydraulic engineering cofferdam gate control system based on PLC, its characterized in that includes: the hydraulic driving and detecting assembly comprises a left hydraulic cylinder and a right hydraulic cylinder which are respectively arranged at two sides of the gate, a left electro-hydraulic proportional valve and a right electro-hydraulic proportional valve which are respectively used for controlling the left hydraulic cylinder and the right hydraulic cylinder, and a left displacement sensor and a right displacement sensor which are respectively used for detecting the displacement of the left hydraulic cylinder and the right hydraulic cylinder; the controller is electrically connected with the left electro-hydraulic proportional valve, the right electro-hydraulic proportional valve, the left displacement sensor and the right displacement sensor, and is internally provided with a logic operation unit which executes the functions comprising the following modules: the discrete state observation module is used for receiving the target position track and the detection values of the left displacement sensor and the right displacement sensor, and estimating the position estimation value, the speed estimation value and the total disturbance estimation value of the hydraulic cylinders at the two sides by using a state observation algorithm; the disturbance characteristic identification module is used for calculating disturbance fluctuation indexes and movement direction factors according to the speed estimated value and the total disturbance estimated value and judging the current working condition state of the system according to the disturbance fluctuation indexes and the movement direction factors, wherein the working condition state at least comprises a normal operation working condition, a Shan Ceka resistance working condition and a turbulent impact working condition; The virtual shaft parameter scheduling module is used for establishing a virtual synchronous coupling relation between hydraulic cylinders at two sides, and adjusting a virtual rigidity coefficient and a virtual damping coefficient of the virtual synchronous coupling relation in real time according to the working condition state and generating an auxiliary excitation signal; And the control law synthesis module is used for calculating and outputting control voltage to the left electro-hydraulic proportional valve and the right electro-hydraulic proportional valve according to the position estimated value, the speed estimated value, the total disturbance estimated value, the virtual stiffness coefficient, the virtual damping coefficient and the auxiliary excitation signal.
2. The PLC-based hydraulic engineering cofferdam gate control system of claim 1, wherein the discrete state observation module constructs an extended state model including a position state, a speed state and a disturbance state; the discrete state observation module calculates tracking errors between the position estimation value and the detection value, and corrects and updates the disturbance state, the speed state and the position state by utilizing the tracking errors, wherein the total disturbance estimation value is used for representing the total disturbance of the system including friction force, water flow impact force and model uncertainty.
3. The PLC-based hydraulic engineering cofferdam gate control system of claim 1, wherein the disturbance characteristic identification module is configured with a sliding data window for collecting the total disturbance estimated value within a set period of time; The disturbance characteristic identification module obtains the disturbance fluctuation index by calculating the standard deviation or the variation coefficient of the data in the sliding data window, and determines the movement direction factor by judging whether the direction of the total disturbance estimated value is opposite to the direction of the speed estimated value.
4. The PLC-based hydraulic engineering cofferdam gate control system of claim 3, wherein the specific logic for determining the working condition by the disturbance characteristic identification module is as follows: When the disturbance fluctuation index exceeds a preset turbulence threshold value, judging the turbulence impact working condition; when the disturbance fluctuation index does not exceed the turbulence threshold, the movement direction factor indicates that the disturbance direction is opposite to the movement direction, and meanwhile, the amplitude of the total disturbance estimated value exceeds a preset steady-state threshold, the Shan Ceka resistance working condition is judged; And in addition to the above, judging the normal operation condition.
5. The PLC based hydraulic engineering cofferdam gate control system of claim 1, wherein the virtual shaft parameter scheduling module configures the virtual stiffness coefficient and the virtual damping coefficient to a preset high stiffness value and a preset high damping value under the normal operation condition so as to maintain the rigidity synchronization of the hydraulic cylinders at both sides; And under the turbulent impact working condition, configuring the virtual stiffness coefficient and the virtual damping coefficient to be lower than preset low values of the high stiffness value and the high damping value so as to reduce the coupling strength between the hydraulic cylinders at two sides.
6. The PLC-based hydraulic engineering cofferdam gate control system of claim 1, wherein the virtual axis parameter scheduling module performs an asymmetric parameter scheduling strategy under the Shan Ceka block condition: aiming at a hydraulic cylinder at one side with blocking, keeping the virtual rigidity coefficient unchanged and generating the auxiliary excitation signal which is non-zero; and aiming at the hydraulic cylinder at the normal side without blocking, reducing the virtual rigidity coefficient to a preset relaxation threshold value, and generating no auxiliary excitation signal.
7. The PLC-based hydraulic engineering cofferdam gate control system of claim 1, wherein the control law synthesis module calculates the control voltage of the hydraulic cylinder at any side, comprising: calculating a linear feedback control amount for eliminating a track tracking error; calculating a virtual coupling correction term based on the virtual stiffness coefficient, the virtual damping coefficient and the position estimation difference value and the speed estimation difference value of the hydraulic cylinders at two sides; Summing the linear feedback control quantity and the virtual coupling correction term, and subtracting the total disturbance estimated value to perform feedforward compensation to obtain an intermediate control quantity; and normalizing the intermediate control quantity by using a system nominal control gain, and superposing the auxiliary excitation signal to obtain the control voltage.
8. The PLC-based hydraulic engineering cofferdam gate control system of claim 7, wherein the control law synthesis module calculates the linear feedback control amount by adopting a proportional-differential control strategy, and the specific calculation mode is as follows: Calculating the product of the position feedback gain and the position tracking error as a proportional term; Calculating the product of the speed feedback gain and the speed estimation value as a differential term; calculating a difference between the proportional term and the derivative term as the linear feedback control amount; the position tracking error is the difference value between the target position track and the position estimation value.
9. The PLC based hydraulic engineering cofferdam gate control system of claim 8, wherein the position feedback gain and the speed feedback gain are parametrically configured based on controller bandwidth; the position feedback gain is configured as a square value of the controller bandwidth, and the speed feedback gain is configured as a double value of the controller bandwidth; And the value range of the controller bandwidth is configured to be less than one fifth to one third of the observation bandwidth of the discrete state observation module.
10. The PLC-based hydraulic engineering cofferdam gate control system of claim 7, wherein said control law combining module further comprises an amplitude limiting link: Presetting a maximum allowable control voltage and a minimum allowable control voltage; comparing the calculated control voltage with the maximum allowable control voltage and the minimum allowable control voltage; Outputting the maximum allowable control voltage if the control voltage is greater than the maximum allowable control voltage; Outputting the minimum allowable control voltage if the control voltage is smaller than the minimum allowable control voltage; otherwise, directly outputting the calculated control voltage.

Description

Hydraulic engineering cofferdam gate control system based on PLC Technical Field The invention relates to the technical field of water conservancy control, in particular to a water conservancy project cofferdam gate control system based on a PLC. Background The cofferdam gate in large hydraulic engineering generally adopts a double hydraulic cylinder driving opening and closing mode, namely, a set of hydraulic driving devices are respectively arranged at the left side and the right side of the gate. Because the gate span is big and structural rigidity is limited, the displacement height synchronization of two pneumatic cylinders about must be guaranteed in the lift in-process. If the hydraulic cylinders on the two sides are asynchronous, the gate is blocked due to light weight, and the gate metal structure is distorted and deformed due to heavy weight, so that the guide rail and the sealing assembly are damaged. The current cofferdam gate control system mostly adopts an electrohydraulic proportional control technology based on PLC, and common synchronization strategies comprise master-slave control, cross coupling control or equivalent control. The control algorithm is typically based on the PID (proportional-integral-derivative) principle, by setting fixed control parameters to eliminate position errors. However, the physical environment of the cofferdam gate in actual operation is relatively complex. The hydraulic system has nonlinear characteristics, such as large dynamic and static friction force variation applied to the hydraulic cylinder during low-speed operation, and the phenomenon of creeping is easy to generate, so that the low-speed tracking precision is influenced. More importantly, the existing synchronous control strategies mostly assume that the system is in an ideal or quasi-static environment, and lack adaptability to complex external working conditions. In actual operation, the gate is often impacted by irregular water flow. When encountering strong turbulence, if the synchronous coupling strength of the control system is too high (i.e. absolute rigid synchronization is pursued), the instantaneous water flow impact suffered by the hydraulic cylinder on one side can be rapidly transmitted to the other side through the control algorithm, so that the system generates reciprocating oscillation between the two sides, and the operation stability is affected. In addition, the river channel is often accompanied by floaters such as branches, sediment and the like. If a single-sided mechanical jam (e.g., a foreign object stuck into the rail) occurs, conventional synchronous control logic often cannot distinguish whether this is an external resistance disturbance or a mechanical failure, and still attempts to increase the output force to maintain synchronization. In this case, the hydraulic cylinder on the non-blocked side will continue to push the gate forcibly, but the blocked side cannot move, which will cause a huge shearing force to act on the gate body, which is very liable to cause permanent damage to the mechanical structure. The prior art has difficulty in balancing between maintaining high precision synchronization and achieving flexible protection, and lacks a classification handling mechanism for turbulent impact and mechanical jamming. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a hydraulic engineering cofferdam gate control system based on a PLC, which solves the problems that a hydraulic cylinder at one side without blocking can continuously and forcedly push a gate and the blocking side cannot move, so that huge shearing force acts on a gate body and permanent damage of a mechanical structure is easily caused. The hydraulic engineering cofferdam gate control system based on the PLC comprises a hydraulic driving and detecting assembly and a controller. The hydraulic driving and detecting assembly comprises a left hydraulic cylinder and a right hydraulic cylinder which are respectively arranged on two sides of the gate, a left electro-hydraulic proportional valve and a right electro-hydraulic proportional valve which are respectively used for controlling the left hydraulic cylinder and the right hydraulic cylinder, and a left displacement sensor and a right displacement sensor which are respectively used for detecting the displacement of the left hydraulic cylinder and the right hydraulic cylinder. The controller is electrically connected with the left electro-hydraulic proportional valve, the right electro-hydraulic proportional valve, the left displacement sensor and the right displacement sensor. The controller is internally provided with a logic operation unit, and the logic operation unit executes functions comprising a discrete state observation module, a disturbance characteristic identification module, a virtual axis parameter scheduling module and a control law synthesis module. Preferably, the discrete state observation module is used