Underwater leveling measurement control method and system and leveling ship with underwater leveling measurement control system

Abstract

The invention discloses an underwater leveling measurement control method and system and a leveling ship with the underwater leveling measurement control system. The method comprises the steps that S100, a tide gauge station is arranged near an engineering project point, and pressure sensors are arranged on the tide gauge station, oil cylinder supporting legs and a leveling hopper respectively; s200, the pressure of a pressure sensor in the tide station is measured, the water depth of a pressure measuring point is calculated, and the water depth is converted into the elevation; s300, the pressure of pressure sensors on oil cylinder supporting legs and the leveling hopper is measured, and smooth filtering processing is conducted on data; s400, the depth of an oil cylinder supporting leg is calculated, the stroke of the oil cylinder supporting leg is adjusted, and the leveling frame is leveled; s500, the depth of the leveling hopper is calculated, and the elevation of the leveling hopper is calculated according to the elevation calibrated in the tide station; and S600, the elevation of the leveling hopper is compared with the designed elevation, and the stroke of the leveling hopper is adjusted to the designed elevation. The gravel leveling elevation error does not exceed the design requirement, and the elevation of the leveling hopper opening of the underwater bottom-supported leveling frame is accurately measured.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of leveling measurement, and more particularly relates to an underwater leveling elevation measurement control method and system, and a leveling ship with the same. BACKGROUND

[0002] In the field of modern marine engineering, the construction of underwater foundations is a key link that determines the success or safety of the entire project. Whether it is the installation of pile foundations for offshore wind farms, the laying of bridge pier caisson foundation beds for cross-sea bridges, or the sinking of pipe sections for underwater tunnels, or the construction of port terminals, a bearing foundation with extremely high flatness and precise elevation needs to be constructed at the predetermined position on the seabed. The quality of this foundation is directly related to the stability of the superstructure, the uniformity of stress distribution, and the safety of long-term use. If there is an elevation error or unevenness on the foundation surface, it will lead to difficulties in structural installation, uneven settlement, and even structural damage, causing huge economic losses and safety hazards. Therefore, real-time and accurate measurement and control of the elevation of the leveling surface during underwater high-precision leveling operations is a crucial core technology in the field of marine engineering.

[0003] Currently, there are many existing technical methods for underwater elevation measurement in the industry. Traditional methods mainly rely on divers carrying leveling rods, connecting pipes and other tools for manual measurement, or using lead lines dropped from the ship for depth measurement, but such methods are low in efficiency, high in labor intensity and high in safety risk. With the development of technology, remote measurement methods have become the mainstream, mainly including acoustic measurement and pressure measurement. Acoustic measurement usually uses a multi-beam depth measurement system installed on a measurement ship to scan the leveling area, or uses an underwater acoustic positioning system such as an ultra-short baseline to position the leveling equipment in three dimensions, thereby obtaining its depth information. Pressure measurement is to install a high-precision pressure sensor directly on the underwater leveling equipment, and to measure the hydrostatic pressure generated by the water body to inversely calculate the underwater depth.

[0004] However, the above prior art has obvious limitations and inherent defects in practical application. The manual measurement method based on divers has poor accuracy and is greatly affected by the environment, which cannot meet the requirements of modern engineering. The acoustic measurement method can cover a large area, but its vertical accuracy is much lower than the horizontal accuracy, and it is easily affected by the sound speed profile distortion caused by the change of water temperature and salinity, the multipath effect and the interference of water waves, making it difficult to achieve continuous, stable and high-precision real-time control. The most widely used pressure sensor method has a core defect that it measures the depth relative to the dynamic water surface. The sea level itself is not a fixed reference, and it is affected by many factors such as tides, waves, storm surges and atmospheric pressure changes, and constantly fluctuates. If the measured depth is directly used for height control, the error of several meters caused by tides will be directly transmitted to the final engineering entity, which is absolutely unacceptable. Therefore, how to eliminate the interference caused by the change of dynamic water surface and establish a stable underwater height reference is a key problem to be solved for the existing technology. SUMMARY

[0005] In view of the above defects or improvement needs of the prior art, the present application provides an underwater grading height measurement control method and system and a grading ship with the same, which establishes a complete and high-precision measurement control link from the land elevation reference to the underwater fixed tide station and then to the mobile operation platform, realizes the fundamental change of the underwater grading operation from the traditional manual experience dominant mode to the high-precision and automated unmanned construction mode, and realizes that the height error of the gravel grading is not more than the design requirement and the height of the grading hopper mouth of the underwater bottom grading frame is accurately measured.

[0006] To achieve the above object, according to a first aspect of an embodiment of the present application, a kind of underwater grading measurement control method is provided, which is characterized by comprising the following steps: S100, a tide station is arranged near the engineering project point, pressure sensors are arranged in the pressure measuring point of the tide station, and pressure sensors are arranged at the same height of each oil cylinder leg and on the grading hopper; S200, the pressure of the pressure sensor in the tide station is measured, the water depth of the pressure measuring point is calculated by the pressure, and then the water depth is converted into elevation for calibration; S300, the pressure of the pressure sensor on each oil cylinder leg and the grading hopper is measured, and the obtained data is subjected to smoothing filtering processing; S400, the depth of each oil cylinder leg is calculated by the pressure data on the oil cylinder leg, and the travel of each oil cylinder leg is adjusted according to the depth comparison of the oil cylinder leg to level the grading frame; S500, the depth of the grading hopper is calculated by the pressure data on the grading hopper, and the height of the grading hopper is calculated according to the calibrated height of the tide station; S600, compare the elevation of the grading hopper with the design elevation, adjust the travel of the grading hopper synchronously, so that the grading hopper reaches the design elevation position, and then moves within the design elevation to pave the material.

[0007] Further, in step S100, the tide station is arranged in the steel pipe, the steel pipe is arranged towards the seabed, and the bottom end is open to the water body and the top end penetrates the water surface. The tide station comprises a steel wire rope and a counterweight, and the pressure sensor on the tide station is arranged on the counterweight and hoisted at the monitoring point with the counterweight. The opening at the bottom end of the steel pipe is connected to the water body, so that the water level inside and outside the steel pipe is equal, and the steel pipe blocks the waves of the external water surface, avoiding the interference of the fluctuation of external waves on the water depth monitoring.

[0008] Further, in step S200, the original reading of the pressure sensor of the tide station is accurately converted into an absolute water surface elevation in a unified geodetic coordinate system which changes with time, and specifically includes: S201, synchronous and high-precision observation of the external reference and the internal pressure sensor in a time window with stable sea conditions: the instantaneous water surface elevation at the calibration time is accurately determined by using a high-precision measuring instrument; at the same time , the total pressure , temperature , salinity , and atmospheric pressure measured by the pressure sensor in the tide station are recorded; S202, the vertical distance from the land reference point with known orthometric height to the water surface is accurately measured by using a level or a laser range finder, and the reference water surface elevation is obtained: ; S203, considering the changes of water density and local gravitational acceleration with depth, the water depth is inversely calculated from the pressure by using the integral equation of fluid statics.

[0009] Further, in step S203, the net water pressure obtained by removing the atmospheric pressure is calculated, and specifically includes: , wherein, is the water depth at the pressure measuring point, is the in-situ density of the water body which changes with depth z, is the salinity, is the temperature, is the gravitational acceleration which changes with depth z and geographic latitude .​ Water depth at the pressure point The upper limit of the integral appears, and the integrand itself also depends on the integral variable z, so there is no analytical solution, and numerical methods need to be used to solve it, specifically: Define a function : , Then find a Make , solve by Newton-Raphson iteration method, the iteration formula is: , Where, is the water density at depth z, is the acceleration of gravity at depth z, is the water depth estimate value of the kth iteration, is the derivative at .

[0010] Further, step S203 also includes after: S204, determine the absolute elevation of the pressure sensor itself at the pressure point : .

[0011] Further, in step S300, to cope with the high nonlinearity of underwater motion, unscented Kalman filter is used to fuse multi-source sensor data, and optimal estimation of the complete six-degree-of-freedom state of the leveling frame is carried out, specifically: S301, establish a state vector to describe the complete motion state of the leveling frame: , Where, is the position vector, is the velocity vector, is the unit quaternion of attitude, is the bias estimate of acceleration, is the bias estimate of gravity acceleration; The state vector The nonlinear dynamic process model under discrete time is: , Where, for a nonlinear state transition function and external inputs to predict the state at the current time , a process noise vector.

[0012] Further, after step S301, the method further comprises: S302, selecting a set of sampling points to approximate the probability distribution of the state, and directly transmitting these points through a nonlinear function to predict the step, which is: , then calculating the predicted mean and covariance, specifically: , , wherein, is the state dimension, is the weight, is the process noise covariance matrix, is a nonlinear state transition function propagated Sigma points, is the weight for calculating the weighted average, is the weight for calculating the weighted covariance, is the prior state estimate, is the prior error covariance matrix.

[0013] Further, in step S400, in order to realize fast, accurate and physically constrained leveling, a model predictive control strategy is adopted to establish the attitude error dynamics model of the leveling frame: define the attitude error vector , its second-order dynamics equation is: , wherein, is the roll angle error, is the pitch angle error, is the inertia matrix, is the Coriolis force and centrifugal force term, is the restoring moment generated by gravity and buoyancy, is the control moment vector generated by the cylinder outriggers, is the external disturbance moment.

[0014] Further, the dynamic behavior of the levelling platform is then switched by a sliding mode control, which requires the design of a sliding surface, when the attitude error dynamics model reaches this sliding surface, its subsequent dynamic behavior will be determined by the equation of the manifold itself, regardless of the complexity of the original system dynamics and uncertainties, the sliding surface is defined as: , where, is the sliding variable vector, is a positive diagonal matrix, when the attitude error dynamics model is on the sliding surface, the error exponentially converges to zero at a speed, i.e. ; The control moment vector generated by the cylinder outriggers is required to be designed so that the system state can reach the sliding surface and remain on it in finite time from any initial position, the control law is designed using the exponential reaching law, which includes equivalent control and switching control, the total control law is: , where, is the estimated value of the attitude error dynamics model, is a positive gain matrix, is a sign function; The sign function will cause the control output to produce high-frequency back-and-forth switching near the sliding surface, this phenomenon is called "chattering", which will cause damage to the hydraulic valve; in order to eliminate chattering in practical applications, the discontinuous sign function is replaced by a continuous saturation function within its boundary layer Φ: , where, is the thickness of the boundary layer.

[0015] Further, in step S400, in order to achieve fast, accurate and physically constrained levelling, a model predictive control strategy is adopted, and the attitude error dynamics model of the levelling platform is established: Define the attitude error vector , its second-order dynamics equation is: , where, is the roll angle error, is the pitch angle error, is the inertia matrix, is the Coriolis and centrifugal force terms, is the restoring moment due to gravity and buoyancy forces, is the control moment vector generated by the cylinder legs, is the external disturbance moment.

[0016] Further, the dynamic behavior of the grade-er is then switched by a sliding mode control, which requires the design of a sliding surface, when the attitude error dynamics model reaches this surface, its subsequent dynamic behavior will be determined by the equation of the manifold itself, regardless of the complexity of the original system dynamics and uncertainties, the sliding surface is defined as: , where, is the sliding variable vector, is a positive definite diagonal matrix, when the attitude error dynamics model is on the sliding surface, the error exponentially converges to zero at a rate of, .

[0017] Further, the control moment vector generated by the cylinder legs is required to be designed so that the system state can reach and remain on the sliding surface in finite time from any initial position, the control law is designed using an exponential reaching law, which includes equivalent control and switching control, the total control law is: , where, is the estimated value of the attitude error dynamics model, is a positive definite gain matrix, is a sign function.

[0018] Further, in step S500, by synchronously measuring the hydrostatic pressure at the pressure measuring point and the grade-er's hopper, the instantaneous static pressure difference between the two is calculated, while the elevation difference between the pressure measuring point and the grade-er's hopper and the pressure difference between them are not a simple linear relationship, because the density of water and the local gravitational acceleration will change with the water depth, their relationship is described by the integral of fluid statics: , where, the instantaneous elevation of the screed hopper, the absolute elevation of the pressure sensor itself at the pressure measuring point, the in-situ density at time t and water depth z, the gravity acceleration at water depth z and geographic latitude .

[0019] Further, since the upper limit of the integral appears, a root-finding function with E as the variable is constructed : , a value of E is found at each time t that makes , which is solved by the Newton-Raphson iteration method, and the iteration formula is: , , wherein, E k is the elevation estimate value of the kth iteration; the iteration process converges quickly according to the real-time pressure difference , so as to obtain a high-precision screed hopper elevation solution .

[0020] According to a second aspect of the embodiment of the present application, a control system for measuring the elevation of underwater screeding based on pressure calibration of a tide station is provided, comprising: a data acquisition module: used for setting a tide station near the project point, setting pressure sensors in the pressure measuring points in the tide station, and setting pressure sensors at the same height of each oil cylinder leg and on the screed hopper; an elevation calibration module: used for measuring the pressure of the pressure sensors in the tide station, calculating the water depth of the pressure measuring points through the pressure, and then converting the water depth into elevation for calibration; a data processing module: used for measuring the pressure of the pressure sensors on each oil cylinder leg and the screed hopper, and performing smoothing filtering processing on the obtained data; an initial leveling module: used for calculating the depth of each oil cylinder leg through the pressure data of the oil cylinder legs, adjusting the stroke of each oil cylinder leg according to the depth comparison of the oil cylinder legs, and leveling the screed frame; an elevation calculation module: used for calculating the depth of the screed hopper through the pressure data of the screed hopper, and calculating the elevation of the screed hopper according to the calibrated elevation in the tide station; an elevation adjustment module: used for comparing the elevation of the screed hopper with the design elevation, synchronously adjusting the stroke of the screed hopper, making the screed hopper reach the design elevation position, and then moving the screed hopper within the design elevation to lay the material.

[0021] According to a third aspect of the embodiments of the present application, there is provided a leveling boat, which is a split leveling boat for a boat frame and is controlled by using an underwater leveling measurement control method.

[0022] Further, the boat body is provided with a bow, a stern, a port side, a starboard side, a transverse direction along the X axis, and a longitudinal direction along the Y axis, a moon pool is arranged in the center of the boat body, the boat body comprises a main deck and a second deck, a material feeding and throwing device is arranged on the second deck and crosses the moon pool, a lifting mechanism is arranged on the main deck, and a lifting leveling frame device is arranged on the lifting mechanism, a stone chute device is arranged between the material feeding and throwing device and the lifting leveling frame device.

[0023] Further, the material feeding and throwing device comprises a walking trolley sliding device arranged on the second deck and parallel to the two sides of the moon pool in the transverse direction, a walking trolley is slidingly arranged on the walking trolley sliding device, the walking trolley has a box-shaped double-beam structure, a walking trolley driving device is arranged on the walking trolley and drives the walking trolley to slide along the walking trolley sliding device, a second belt conveyor is arranged on the walking trolley in the length direction of the walking trolley, a walking trolley sliding device is arranged on the walking trolley in the length direction of the walking trolley, a walking trolley is slidingly arranged on the walking trolley sliding device, and a walking trolley driving device is arranged on the walking trolley and drives the walking trolley to slide along the walking trolley sliding device, a first belt conveyor is arranged on the boat body and supplies material to the second belt conveyor.

[0024] Further, the lifting mechanism comprises four lifting devices arranged between the boat body and the lifting leveling frame device, the four lifting devices are arranged on the main deck and are symmetrically arranged along the transverse and longitudinal center planes of the main deck, the lifting device comprises a lifting hoist arranged on the boat body, a first steel wire rope is wound on the lifting hoist, a movable pulley is arranged along the first steel wire rope, a first fixed pulley is further arranged on the boat body, the first steel wire rope passing through the movable pulley passes through the first fixed pulley, and the first steel wire rope passing through the first fixed pulley is connected to the boat body again; a turning pulley block is further arranged on the boat body, the turning pulley block comprises a first horizontal turning pulley, a second horizontal turning pulley, and a vertical turning pulley, a second steel wire rope is connected to the movable pulley, one end of the second steel wire rope connected to the movable pulley passes through the first horizontal turning pulley, the second horizontal turning pulley, and the vertical turning pulley, and the other end of the second steel wire rope is connected to the lifting leveling frame device.

[0025] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects: 1.The underwater leveling elevation measurement control method of the present application realizes the fundamental change from the traditional manual experience dominant mode to the high-precision and automated unmanned construction mode of underwater leveling operation by establishing a complete and high-precision measurement control link from the land elevation reference to the fixed tide station and then to the mobile operation platform. The elevation error of the rubble leveling is not more than the design requirement, and the elevation of the leveling hopper mouth of the underwater bottom sitting leveling frame is accurately measured.

[0026] 2.The underwater leveling elevation measurement control method of the present application realizes complete immunity to complex hydrological environmental changes such as tides, waves, and air pressure by establishing a direct differential pressure solving model between the fixed tide station and the mobile operation point, and integrating the precise physical oceanographic parameters considering the changes of water density and gravity with depth for nonlinear inversion. This method discards the unstable water surface as an intermediate reference and directly traces the elevation measurement to the stable geodetic reference, thereby fundamentally ensuring the absolute accuracy of the elevation measurement and the high reliability in the long-term operation process.

[0027] 3.The underwater leveling elevation measurement control method of the present application realizes effective suppression and rapid compensation of strong disturbances such as unknown water flow impact, equipment load mutation, and system model uncertainty in complex underwater environments by introducing advanced nonlinear robust control algorithms such as sliding mode variable structure control and adaptive fuzzy PID in the attitude leveling and elevation tracking loop. This intelligent control strategy ensures the rapid convergence of attitude control and the smooth and undisturbed elevation tracking of the leveling frame under various working conditions, significantly improving the dynamic performance of the system and the operation robustness in severe sea conditions.

[0028] 4.The underwater leveling elevation measurement control method of the present application realizes comprehensive, accurate, and smooth real-time estimation of all six degrees of freedom motion states such as translation and rotation of the leveling frame by using unscented Kalman filtering to deeply integrate heterogeneous information sources such as inertial navigation, acoustic positioning, and pressure sensors. This high-precision dynamic sensing capability not only provides a reliable data foundation for the application of advanced control algorithms, but also constitutes the core of system intelligent decision-making, thereby improving the automation level from simple instruction execution to intelligent new height with environmental perception and adaptive capability. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a ship frame separation type leveling ship structure schematic diagram of the embodiment of the present application. Figure 2 It is a leveling frame structure schematic diagram of the embodiment of the present application. Figure 3 It is a flowchart of a kind of underwater leveling measurement control method of the embodiment of the present application. Figure 4 It is a top view of a riprap leveling ship of the embodiment of the present application. Figure 5 This is a front view of a stone-throwing leveling vessel according to an embodiment of the present invention; Figure 6 This is a right view of a stone-throwing leveling boat according to an embodiment of the present invention; Figure 7 This is a top view of the main deck of a stone-throwing and leveling vessel according to an embodiment of the present invention; Figure 8 This is a layout diagram of the lifting device of a stone-throwing leveling boat according to an embodiment of the present invention.

[0030] In all the accompanying drawings, the same reference numerals denote the same technical features, specifically: 1-Hull, 2-Material conveying and feeding device, 3-Lifting device, 4-Leveling frame device, 5-Slippery stone pipe device, 21-Traveling trolley sliding device, 22-Traveling trolley, 24-Second belt conveyor device, 26-Traveling trolley, 28-First belt conveyor device, 30-Lifting winch, 31-First wire rope, 32-Moving pulley, 33-First fixed pulley, 34-First horizontal steering pulley, 35-Second horizontal steering pulley, 36-Vertical steering pulley, 37-Second wire rope, 100-Moon pool, 101-Main deck, 102-Second deck. Detailed Implementation

[0031] 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.

[0032] like Figure 1 , 2 As shown, during the operation of the detachable leveling vessel, the mother vessel floats on the water, while the leveling frame sits on the bottom in the foundation trench. There is no rigid connection between the vessel and the frame. The hull rises and falls with the tide level, while the leveling frame is unaffected by tide changes. The leveling frame is supported on the seabed by hydraulic cylinder legs at its four corners. A leveling hopper is also installed on the leveling frame, moving along its plane to lay crushed stone to form a cushion layer on the seabed. During the laying of crushed stone, the elevation of the leveling hopper needs to be measured to control the leveling height error of the cushion layer to not exceed the relevant requirements.

[0033] Example 1 like Figure 3 As shown, this embodiment of the invention provides an underwater leveling measurement and control method, which specifically includes the following steps: S100, setting a tide station near the project site, setting pressure sensors in the pressure measuring points in the tide station, and setting pressure sensors at the same height of each oil cylinder leg and on the leveling hopper; S200, measuring the pressure of the pressure sensors in the tide station, calculating the water depth of the pressure measuring points through the pressure, and then converting the water depth into elevation for calibration; S300, measuring the pressure of the pressure sensors on each oil cylinder leg and the leveling hopper, and performing smoothing filtering processing on the obtained data; S400, calculating the depth of each oil cylinder leg through the pressure data on the oil cylinder leg, adjusting the stroke of each oil cylinder leg according to the depth comparison of the oil cylinder leg, and leveling the leveling frame; S500, calculating the depth of the leveling hopper through the pressure data on the leveling hopper, and calculating the elevation of the leveling hopper according to the calibrated elevation in the tide station; S600, comparing the elevation of the leveling hopper with the design elevation, synchronously adjusting the stroke of the leveling hopper, making the leveling hopper reach the design elevation position, and then moving the leveling hopper within the design elevation to pave the material.

[0034] In step S100, the tide station is arranged in a steel pipe, the steel pipe is arranged on the seabed, the bottom end of the steel pipe is open and communicates with the water body, and the top end penetrates the water surface. The tide station includes a steel wire rope and a counterweight, and the pressure sensor on the tide station is arranged on the counterweight and hoisted at the monitoring point with the counterweight. The bottom end of the steel pipe is open and communicates with the water body, so that the water level inside and outside the steel pipe is equal, and the steel pipe blocks the waves of the outside water surface, avoiding the interference of the fluctuation of the external waves on the water depth monitoring.

[0035] In step S200, the original readings of the pressure sensors in the tide station are accurately converted into an absolute water surface elevation that changes with time in a unified geodetic coordinate system, which specifically includes: S201, synchronously and highly accurately observing the external reference and the internal pressure sensor in a time window with stable sea conditions: accurately measuring the instantaneous water surface elevation at the calibration time by using a high-precision measuring instrument; at the same time , recording the total pressure , temperature , salinity , and atmospheric pressure .

[0036] S202, accurately measuring the vertical distance from the known orthometric land reference point to the water surface by using a level or a laser range finder, to obtain the reference water surface elevation : , ​S203, considering the water density and the variation of local gravity acceleration with depth, the water depth is inverted from pressure using the hydrostatic integral equation: , where, is the net water pressure after removing the influence of atmospheric pressure, is the water depth at the pressure point, is the in-situ density of water varying with depth z, is the salinity, is the temperature, is the gravity acceleration varying with depth z and geographic latitude .

[0037] The water depth at the pressure point appears in the upper limit of integration, and the integrand itself also depends on the integration variable z, so there is no analytical solution, and numerical methods need to be used to solve it, specifically: define a function : , then find a such that , which is solved by the Newton-Raphson iteration method, and the iteration formula is: , where, is the water density at depth z, is the gravity acceleration at depth z, is the water depth estimate value at the kth iteration, is the derivative at .

[0038] S204, determine the absolute elevation of the pressure sensor itself at the pressure point : .

[0039] In step S200, when performing the calibration operation, the GNSS-RTK geodetic surveying technology can be used to accurately determine the absolute height of the top end of the steel pipe of the tide station. By means of the known height and in combination with the fixed installation depth of the pressure sensor in the steel pipe, the absolute height of the pressure sensor measuring point itself can be accurately calibrated. Thus, the tide station establishes a continuous and dynamic underwater height datum connected with the land height control network. The datum can reflect the tidal changes in real time and provide a unified and accurate height reference for the entire underwater operation area.

[0040] In step S300, in order to cope with the high nonlinearity of underwater motion, the unscented Kalman filter is used to fuse multi-source sensor data to optimally estimate the complete six-degree-of-freedom state of the leveling frame. Specifically, the following steps are performed: S301, a state vector is established The complete motion state of the leveling frame is described as follows: , wherein, is a position vector, is a velocity vector, is a unit quaternion of attitude, is a bias estimate of acceleration, is a bias estimate of gravitational acceleration.

[0041] The state vector The nonlinear dynamic process model at discrete time is as follows: , wherein, is a nonlinear state transition function that predicts the state at the current time according to the state at the previous time and the external input , is a process noise vector.

[0042] S302, a set of sampling points are selected to approximate the probability distribution of the state, and these points are directly transmitted through a nonlinear function to predict the step as follows: , Then, the predicted mean and covariance are calculated as follows: , , wherein, is the state dimension, is a weight, for a process noise covariance matrix, for a nonlinear state transition function propagated Sigma points, for weights used to compute a weighted average, for weights used to compute a weighted covariance, for a prior state estimate, for a prior error covariance matrix.

[0043] In step S300, for the dynamic pressure and attitude data collected by the sensors on the oil cylinder legs and the grading hopper, Kalman filtering or complementary filtering algorithm is used to filter out the noise and instantaneous fluctuations caused by equipment movement, water flow impact, etc., and extract real and reliable depth information.

[0044] In step S400, to achieve rapid, accurate and physically constrained grading, a model predictive control strategy is used to establish a posture error dynamics model of the grading frame: define the posture error vector , its second-order dynamics equation is: , wherein, is the roll angle error, is the pitch angle error, is the inertia matrix, is the Coriolis force and centrifugal force term, is the restoring moment generated by gravity and buoyancy, is the control moment vector generated by the oil cylinder legs, is the external disturbance moment.

[0045] Then the dynamic behavior of the grading frame is switched by sliding mode control, which needs to design a sliding mode surface. When the posture error dynamics model reaches this sliding mode surface, the subsequent dynamic behavior will be determined by the equation of the manifold itself, and has nothing to do with the complex dynamics and uncertainties of the original system. The definition of the sliding mode surface is: , wherein, is the sliding mode variable vector, a positive definite diagonal matrix, When the attitude error dynamics model is on the sliding surface, the error converges to zero exponentially, i.e. .

[0046] The control torque vector generated by the cylinder outriggers is required to be designed such that the system state can reach the sliding surface in finite time and stay on it at any initial position. The control law is designed using the exponential reaching law, which consists of an equivalent control and a switching control, and the total control law is: , where, is the estimated value of the attitude error dynamics model, is a positive definite gain matrix, is a sign function.

[0047] The sign function will cause the control output to produce high-frequency back-and-forth switching near the sliding surface, which is called "chattering" and can damage the hydraulic valve. In order to eliminate chattering in practical applications, the discontinuous sign function is replaced by a continuous saturation function within its boundary layer Φ: , where, is the thickness of the boundary layer.

[0048] In step S400, the depth of each cylinder outrigger is calculated according to the pressure data of each cylinder outrigger. More importantly, the system reads the inclination meter or IMU data integrated on the screed in real time to directly obtain the accurate inclination angles of the screed in the roll and pitch directions. The real-time attitude data is compared with the preset level state to form an error signal. Based on the PID control algorithm, the system automatically and accurately adjusts the extension stroke of each cylinder outrigger. If X-direction inclination is detected, the corresponding side outrigger is raised and the other side is lowered until the inclination error converges to the allowable minimum range, thereby realizing rapid, stable, and automatic leveling of the screed.

[0049] In step S500, the instantaneous static pressure difference between the pressure measuring point and the screed is calculated by synchronously measuring the hydrostatic pressure on the pressure measuring point and the screed, but the elevation difference between the pressure measuring point and the screed is not a simple linear relationship with the pressure difference between them, because the density of water and the local gravitational acceleration will change with the water depth, and their relationship is described by the integral of fluid statics: , where, is the instantaneous elevation of the screed, P is the absolute elevation of the pressure sensor itself at the measurement point, R is the in-situ density at time t and depth z, g is the acceleration of gravity at latitude and depth z.

[0050] Since appears in the upper limit of the integral, a root-finding function of E as a variable is constructed : , At each time t, a is found such that is solved by the Newton-Raphson iteration method, and the iteration formula is: , where is the elevation estimate at the kth iteration.

[0051] This iteration process will quickly converge according to the real-time pressure difference , so as to obtain a high-precision smoothing hopper elevation solution .

[0052] In step S500, the pressure sensor data on the smoothing hopper is used to accurately calculate the current water depth of the hopper in combination with the real-time water density, and the real-time elevation reference of the measurement point is called to obtain the real-time absolute elevation of the smoothing hopper. This process is continuous, ensuring that the elevation calculation is still accurate even if the tidal level is constantly changing.

[0053] In step S600, the real-time elevation of the smoothing hopper is continuously compared with the target elevation in the design drawing. At the same time, in order to control the position of the paving plane, an ultra-short baseline underwater acoustic positioning system or an inertial navigation system is integrated to realize real-time positioning of the horizontal position of the smoothing frame. When there is an elevation difference, the system will issue unified and coordinated stroke adjustment instructions to all oil cylinder legs, so that the entire leveled smoothing frame rises or falls smoothly as a whole until the error between the real-time elevation of the smoothing hopper and the design elevation enters the preset precision range. After reaching the design elevation, the control system will accurately control the movement of the smoothing frame according to the preset paving path, while maintaining real-time closed-loop locking of the elevation, so as to carry out efficient, uniform and high-quality paving operations in the specified three-dimensional space.

[0054] Embodiment 2 The embodiment of the present application provides a water-surface leveling elevation measurement control system based on tide gauge pressure calibration, which comprises: The data acquisition module is used for setting a tide station near the engineering project point, setting a pressure sensor at a pressure measuring point in the tide station, and setting pressure sensors at the same height of each oil cylinder support leg and on the leveling hopper respectively; The elevation calibration module is used for measuring the pressure of the pressure sensor in the tide station, calculating the water depth of the pressure measuring point through the pressure, and then converting the water depth into elevation for calibration; The data processing module is used for measuring the pressure of the pressure sensor on each oil cylinder support leg and the leveling hopper, and performing smoothing filtering processing on the obtained data; The initial leveling module is used for calculating the depth of each oil cylinder support leg through the pressure data of the oil cylinder support leg, adjusting the stroke of each oil cylinder support leg according to the depth comparison of the oil cylinder support legs, and leveling the leveling frame; The elevation calculation module is used for calculating the depth of the leveling hopper through the pressure data of the leveling hopper, and calculating the elevation of the leveling hopper according to the calibrated elevation in the tide station; The elevation adjustment module is used for comparing the elevation of the leveling hopper with the design elevation, synchronously adjusting the stroke of the leveling hopper, making the leveling hopper reach the design elevation position, and then moving the leveling hopper within the design elevation to pave the material.

[0055] Embodiment 3 As Figures 4-8 The embodiment of the present application provides a riprapping leveling ship, which comprises a ship body 1. Figure 4 When the ship body 1 is in the state shown in the figure, the upper side is the bow, the lower side is the stern, the left side is the port side, the right side is the starboard side, the direction along the X axis is the transverse direction, the direction along the Y axis is the longitudinal direction, a moon pool 100 is arranged in the center of the ship body 1, the ship body 1 comprises a main deck 101 and a second deck 102, a material conveying and feeding device 2 is arranged on the second deck 102 and crosses the moon pool 100, a liftable leveling frame device 4 is arranged on the main deck 101 through a lifting mechanism, and a riprapping pipe device 5 is arranged between the material conveying and feeding device 2 and the leveling frame device 4.

[0056] The material conveying and feeding device 2 comprises walking cart sliding devices 21 arranged in parallel along the transverse direction of the moon pool 100 on the second deck 102, walking carts 22 are slidingly arranged on the walking cart sliding devices 21, in this embodiment, the walking carts 22 are box-shaped double-beam structures, walking cart driving devices are arranged on the walking carts 22 and drive the walking carts 22 to slide along the walking cart sliding devices 21, second belt conveying devices 24 are arranged on the walking carts 22 along the length direction of the walking carts 22, walking cart sliding devices are arranged on the walking carts 22 along the length direction of the walking carts 22, walking trolleys 26 are slidingly arranged on the walking cart sliding devices, walking trolley driving devices are arranged on the walking trolleys 26 and drive the walking trolleys 26 to slide along the walking cart sliding devices, and first belt conveying devices 28 are arranged on the ship body 1 and supply materials to the second belt conveying devices 24.

[0057] The lifting mechanism comprises more than three lifting devices 3 arranged between the ship body 1 and the screed device 4, in the embodiment, the number of the lifting devices 3 is four, the four lifting devices 3 are arranged on the main deck 101 and symmetrically along the transverse and longitudinal center planes of the main deck 101, the lifting device 3 comprises a lifting winch 30 arranged on the ship body 1, a first steel wire rope 31 is wound on the lifting winch 30, a movable trolley 32 is arranged along the first steel wire rope 31, a first fixed pulley 33 is further arranged on the ship body 1, the first steel wire rope 31 passing through the movable trolley 32 passes through the first fixed pulley 33, the first steel wire rope 31 passing through the first fixed pulley 33 is connected with the ship body 1 again after passing through the movable trolley 32 again; a deflection pulley set is further arranged on the ship body 1, the deflection pulley set comprises a first horizontal deflection pulley 34, a second horizontal deflection pulley 35 and a vertical deflection pulley 36, a second steel wire rope 37 is connected with the movable trolley 32, one end of the second steel wire rope 37 connected with the movable trolley 32 passes through the first horizontal deflection pulley 34, the second horizontal deflection pulley 35 and the vertical deflection pulley 36 and is connected with the screed device 4.

[0058] Those skilled in the art will easily understand that the above description is only the preferred embodiment of the present application and is not used to limit the present application, any modification, equivalent replacement and improvement within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for underwater leveling measurement and control, characterized in that, Includes the following steps: S100. Set up a tide gauge station near the project site. Set up pressure sensors at the pressure measurement points in the tide gauge station. Also set up pressure sensors at the same height of each hydraulic cylinder support leg and on the leveling hopper. S200: Measure the pressure of the pressure sensor in the tide gauge station, calculate the water depth at the pressure measurement point using the pressure, and then convert the water depth into elevation for calibration. S300: Measure the pressure of the pressure sensor on each hydraulic cylinder support leg and the leveling hopper, and perform smoothing and filtering on the obtained data; S400: Calculate the depth of the hydraulic cylinder support leg by using the pressure data on the hydraulic cylinder support leg, and adjust the stroke of each hydraulic cylinder support leg according to the depth comparison to level the leveling frame. S500: Calculate the depth of the leveling hopper based on the pressure data on the leveling hopper, and calculate the elevation of the leveling hopper based on the elevation marked in the tide gauge station. S600: Compare the elevation of the leveling hopper with the design elevation, adjust the stroke of the leveling hopper synchronously to make the leveling hopper reach the design elevation position, and then move it to spread material within the design elevation.

2. The underwater leveling measurement and control method according to claim 1, characterized in that, In step S100, the tide gauge station is located inside a steel pipe, which is driven into the seabed and has its bottom opening connected to the water body, while its top protrudes above the water surface. The tide gauge station includes a steel wire rope and a counterweight. The pressure sensor on the tide gauge station is installed on the counterweight and is hoisted to the monitoring point along with the counterweight. The steel pipe is connected to the water body through an opening at the bottom, so that the water level inside and outside the steel pipe is the same, and the steel pipe blocks the waves on the outside water surface, so as to avoid the external wave fluctuations from interfering with the water depth monitoring.

3. The underwater leveling measurement and control method according to claim 1 or 2, characterized in that, In step S200, the raw readings of the tide gauge station's pressure sensor are precisely converted into a deterministic absolute water surface elevation that varies over time in a unified geodetic coordinate system. This specifically includes: S201. During periods of stable sea conditions, conduct synchronized, high-precision observations of external reference and internal pressure sensors: accurately determine the instantaneous water surface elevation at the calibration time using high-precision measuring instruments; at exactly the same time... Record the total pressure measured by the pressure sensor inside the tide gauge station. ,temperature ,salinity and atmospheric pressure ; S202, From the known positive height The land reference point is used to accurately measure the vertical distance to the water surface using a level or laser rangefinder. The reference water surface elevation was obtained. : ； S203. Considering the changes in water density and local gravitational acceleration with depth, the water depth is inverted from the pressure using the hydrostatic integral equation.

4. The underwater leveling measurement and control method according to claim 3, characterized in that, In step S203, it is necessary to calculate the net water pressure after eliminating the influence of atmospheric pressure. Specifically: ， in, The water depth at the pressure measurement point. The in-situ density of water varies with depth z. Salinity For temperature, For depth z and geographic latitude Changing gravitational acceleration; The water depth at the pressure measurement point Since it appears on the upper limit of integration and the integrand itself depends on the integration variable z, there is no analytical solution. A numerical method is required to solve it, specifically: Define a function : ， Then find one make The solution is obtained using the Newton-Raphson iterative method, and the iterative formula is as follows: ， in, Let z be the density of the water at depth z. The acceleration due to gravity at depth z This is the water depth estimate for the k-th iteration. for exist The derivative at point .

5. The underwater leveling measurement and control method according to claim 4, characterized in that, Step S203 is followed by: S204. Determine the absolute elevation of the pressure sensor itself at the pressure measurement point. : 。 6. The underwater leveling measurement and control method according to claim 5, characterized in that, In step S300, to address the highly nonlinear underwater motion, an unscented Kalman filter is used to fuse multi-source sensor data to optimally estimate the complete six-degree-of-freedom state of the leveling frame. Specifically: S301. Establish a state vector Describe the complete motion state of the leveling frame: ， in, For position vectors, For velocity vectors, For the attitude, the unit quaternion. For the bias estimation of acceleration, For the bias estimate of gravitational acceleration; State vector The nonlinear dynamic process model in discrete time is as follows: ， in, The nonlinear state transition function is based on the state at the previous time step. and external input To predict the state at the current moment , Process noise vector.

7. The underwater leveling measurement and control method according to claim 6, characterized in that, After step S301, the following is also included: S302. Select a set of sampling points to approximate the probability distribution of the state, and directly pass these points through a nonlinear function. The prediction steps are as follows: ， Then the predicted mean and covariance are calculated as follows: ， ， in, For the state dimension, As weight, The process noise covariance matrix is... Nonlinear state transition function The propagated Sigma point The weights used to calculate the weighted average. The weights used to calculate the weighted covariance, For prior state estimation, Let be the prior error covariance matrix.

8. The underwater leveling measurement and control method according to claim 7, characterized in that, In step S400, to achieve fast, accurate leveling that takes into account physical constraints, a model predictive control strategy is adopted to establish a dynamic model of the leveling frame's attitude error: Define attitude error vector , Its second-order dynamic equation is: ， in, For roll angle error, For pitch angle error, The inertia matrix, For the Coriolis force and centrifugal force terms, The restoring torque generated by gravity and buoyancy, The vector of control torque generated by the hydraulic cylinder outriggers. This refers to the external disturbance torque.

9. The underwater leveling measurement and control method according to claim 8, characterized in that, Then, the dynamic behavior of the leveling frame is switched through sliding mode control. This requires designing a sliding surface. When the attitude error dynamic model reaches this sliding surface, its subsequent dynamic behavior will be determined by the equations of the manifold itself, and will be independent of the complex dynamics and uncertainties of the original system. The sliding surface is defined as follows: ， in, Let them be the sliding mode variable vector. It is a positive definite diagonal matrix. When the attitude error dynamic model is on the sliding surface, the error The speed at which the exponential rate converges to zero, i.e. ; It is necessary to design the control torque vector generated by the hydraulic cylinder outriggers. This ensures that the system state can reach and remain on the sliding surface within a finite time from any initial position. An exponential reaching law is used to design the control law, which can take the forms of equivalent control and switching control. The overall control law is: ， in, For the estimated values ​​of the attitude error dynamics model, It is a positive definite gain matrix. It is a symbolic function; The sign function causes the control output to switch back and forth frequently near the sliding surface, a phenomenon known as "chattering," which can damage the hydraulic valve. To eliminate chattering in practical applications, discontinuous sign functions are... Replace it with a saturation function that is continuous within its boundary layer Φ: ， in, The thickness of the boundary layer.

10. The underwater leveling measurement and control method according to claim 9, characterized in that, In step S400, to achieve fast, accurate leveling that takes into account physical constraints, a model predictive control strategy is adopted to establish a dynamic model of the leveling frame's attitude error: Define attitude error vector , Its second-order dynamic equation is: ， in, For roll angle error, For pitch angle error, The inertia matrix, For the Coriolis force and centrifugal force terms, The restoring torque generated by gravity and buoyancy, The vector of control torque generated by the hydraulic cylinder outriggers. This refers to the external disturbance torque.

11. The underwater leveling measurement and control method according to claim 10, characterized in that, Then, the dynamic behavior of the leveling frame is switched through sliding mode control. This requires designing a sliding surface. When the attitude error dynamic model reaches this sliding surface, its subsequent dynamic behavior will be determined by the equations of the manifold itself, and will be independent of the complex dynamics and uncertainties of the original system. The sliding surface is defined as follows: ， in, Let them be the sliding mode variable vector. It is a positive definite diagonal matrix. When the attitude error dynamic model is on the sliding surface, the error The speed at which the exponential rate converges to zero, i.e. .

12. The underwater leveling measurement and control method according to claim 11, characterized in that, It is necessary to design the control torque vector generated by the hydraulic cylinder outriggers. This ensures that the system state can reach and remain on the sliding surface within a finite time from any initial position. An exponential reaching law is used to design the control law, which can take the forms of equivalent control and switching control. The overall control law is: ， in, For the estimated values ​​of the attitude error dynamics model, It is a positive definite gain matrix. It is a symbolic function.

13. The underwater leveling measurement and control method according to claim 1 or 2, characterized in that, In step S500, the instantaneous static pressure difference between the pressure measuring point and the hydrostatic pressure on the leveling hopper is calculated by simultaneously measuring the hydrostatic pressure between the two. The elevation difference between the pressure measuring point and the leveling hopper and the pressure difference between them are not a simple linear relationship, because the density of water and the local gravitational acceleration vary with water depth. Their relationship is described by hydrostatic integrals: ， in, To level the instantaneous elevation of the hopper, This represents the absolute elevation of the pressure sensor itself at the pressure measurement point. Let Z be the in-situ density at time t and water depth z. The water depth is z and the geographical latitude is The gravitational acceleration at that location.

14. The underwater leveling measurement and control method according to claim 13, characterized in that, because Given the upper limit of integration, construct a root-finding function with E as the variable. : ， Find one at each time t Make The solution is obtained using the Newton-Raphson iterative method, and the iterative formula is as follows: ， in, This is the elevation estimate for the k-th iteration; This iterative process will be based on the real-time pressure difference. Rapid convergence yields a high-precision solution for the elevation of the leveled hopper. .

15. An underwater leveling measurement and control system, used to implement the underwater leveling measurement and control method as described in claim 14, characterized in that, include: Data acquisition module: used to set up tide gauge stations near the project site. Pressure sensors are installed at the pressure measurement points in the tide gauge stations, and pressure sensors are also installed at the same height on each hydraulic cylinder support leg and on the leveling hopper. Elevation calibration module: Used to measure the pressure of the pressure sensor in the tide gauge station, calculate the water depth at the pressure measurement point based on the pressure, and then convert the water depth into elevation for calibration; Data processing module: used to measure the pressure of the pressure sensors on each hydraulic cylinder support leg and leveling hopper, and to perform smoothing and filtering on the obtained data; Initial leveling module: used to calculate the depth of the hydraulic cylinder outriggers based on the pressure data on the outriggers, and adjust the stroke of each hydraulic cylinder outrigger according to the depth comparison, so as to level the leveling frame. Elevation calculation module: used to calculate the depth of the leveling hopper based on the pressure data on the hopper, and to calculate the elevation of the leveling hopper based on the elevation marked in the tide gauge station; Elevation adjustment module: Used to compare the elevation of the leveling hopper with the design elevation, and synchronously adjust the stroke of the leveling hopper so that the leveling hopper reaches the design elevation position, and then moves it to spread material within the design elevation.

16. A leveling vessel having the underwater leveling measurement and control method as described in claim 14, characterized in that, It is a flattened vessel with a detachable frame.

17. The leveling vessel according to claim 16, characterized in that, The ship includes a hull (1), with the bow above and the stern below, the port side on the left and the starboard side on the right. The ship is transverse along the X-axis and longitudinal along the Y-axis. A moon pool (100) is located in the center of the hull (1). The hull (1) includes a main deck (101) and a second deck (102). A material conveying and feeding device (2) spanning the moon pool (100) is located on the second deck (102). A liftable leveling frame device (4) is located on the main deck (101) via a lifting mechanism. A stone chute device (5) is located between the material conveying and feeding device (2) and the leveling frame device (4).

18. The leveling vessel according to claim 17, characterized in that, The material feeding device (2) includes a traveling trolley sliding device (21) arranged parallel to the transverse sides of the moon pool (100) on the second deck (102). A traveling trolley (22) is slidably arranged on the traveling trolley sliding device (21). The traveling trolley (22) is a box-type double beam structure. A traveling trolley drive device is provided on the traveling trolley (22) to drive the traveling trolley (22) to slide along the traveling trolley sliding device (21). A second belt conveyor device (24) is provided on the traveling trolley (22) along the length direction of the traveling trolley (22). A traveling trolley sliding device is provided on the traveling trolley (22) along the length direction of the traveling trolley (22). A traveling trolley (26) is slidably arranged on the traveling trolley sliding device. A traveling trolley drive device is provided on the traveling trolley (26) to drive the traveling trolley (26) to slide along the traveling trolley sliding device. A first belt conveyor device (28) is provided on the hull (1) to supply material to the second belt conveyor device (24).

19. The leveling vessel according to claim 18, characterized in that, The lifting mechanism includes four lifting devices (3) located between the hull (1) and the leveling frame device (4). All four lifting devices (3) are located on the main deck (101) and are symmetrically arranged along the transverse and longitudinal center planes of the main deck (101). Each lifting device (3) includes a lifting winch (30) located on the hull (1). A first steel wire rope (31) is wound on the lifting winch. A movable pulley (32) is provided along the first steel wire rope (31). A first fixed pulley (33) is also provided on the hull (1). The first steel wire rope (31) passes around the movable pulley (32) and then passes around the first fixed pulley (33). 3) The first wire rope (31) that passes over the first fixed pulley (33) passes over the movable pulley (32) again and is connected to the hull (1); a steering pulley group is also provided on the hull (1), which includes a first horizontal steering pulley (34), a second horizontal steering pulley (35) and a vertical steering pulley (36). A second wire rope (37) is connected to the movable pulley (32). The second wire rope (37) that is connected to the movable pulley (32) at one end passes through the first horizontal steering pulley (34), the second horizontal steering pulley (35) and the vertical steering pulley (36) and is connected to the leveling frame device (4).

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