A method of measuring hydrological flow with amphibious equipment

Abstract

The application discloses a kind of amphibious equipment measuring hydrologic flow method, it is related to hydrologic flow monitoring field, including using bottom as hull, top installation multi-rotor amphibious platform, integration ADCP, GNSS / IMU, environmental sensor etc., by real-time sensing water flow, wave, wind and ship attitude, with the aid of prediction model, interference trend and threat level are predicted in advance.Adopt active stabilization control algorithm, dynamically coordinate and distribute the power output of underwater propeller and air rotor, suppress ship movement to the measurement allowable error range, its core lies in intelligent switching operation mode: in low water, rely on underwater power contact measurement;High water or flood, lift off and use GNSS positioning to carry out non-contact type hovering measurement, completely solve the traditional cableway flow measurement easy broken, sailing ADCP in torrent easy out of control failure industry problem, realize full range, high precision, full-automatic hydrologic flow online monitoring, provide reliable technical means for flood control and disaster mitigation and water resources management.

Description

Technical Field

[0001] This invention relates to the field of hydrological flow monitoring, specifically a method for measuring hydrological flow using amphibious equipment. Background Technology

[0002] The most widely recognized accurate flow measurement methods in the hydrological industry today are the rotor current meter and the mobile ADCP measurement method. Other measurement methods are usually compared with these methods to verify the accuracy of the data. Among them, the most common are the rotor current meter measurement method and the mobile ADCP measurement method.

[0003] The current measurement method using a rotor-type current meter mounted on a hydrological suspension cableway suffers from low measurement efficiency, low accuracy, and high operational risks. Current fully automated cableways also cannot automatically measure flow without human intervention, indicating a low level of automation. Furthermore, cableway construction is very costly, and flow measurement is impossible during medium to high water levels. The ADCP method using a mobile unmanned surface vessel improves measurement efficiency and accuracy to some extent and reduces costs; however, this semi-automatic measurement method remains dangerous during floods and cannot achieve accurate flow measurement during medium to high water levels. Summary of the Invention

[0004] The purpose of this invention is to provide a method for measuring hydrological flow using amphibious equipment, solving the problem of flow monitoring during medium and high water levels, realizing online measurement of the entire flow range, and providing more effective measurement in the face of natural disasters such as floods exceeding the standard, thereby solving the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for measuring hydrological flow using amphibious equipment, comprising the following steps:

[0006] Step 1: Real-time acquisition of multi-dimensional water flow velocity vectors around the hull of amphibious equipment; use the water flow velocity vector data to infer the wave characteristics of the water flow; and simultaneously acquire airflow data around the hull to construct the underwater, surface, and above-water environmental force field regions.

[0007] Step 2: Real-time acquisition of the ship's multi-degree-of-freedom motion attitude, absolute position, angular velocity, and linear acceleration, including roll angle, pitch angle, bow angle, heave, longitudinal displacement, and lateral displacement;

[0008] Step 3: Input the water flow velocity vector data into the pre-trained prediction model to predict the future water flow direction, velocity change trend and hydrodynamic interference to the ship hull, and use the wave feature data to predict the wave force of the waves acting on the ship hull position within the set time.

[0009] Step 4: Set the stability threshold for each degree of freedom motion in the multi-degree-of-freedom motion attitude of the hull, input the predicted wave force and predicted hydrodynamic disturbance data into the dynamic motion mathematical model of the hull, detect whether the hull will exceed the preset stability threshold under the action of the predicted wave force and predicted hydrodynamic disturbance, and output the corresponding evaluation feature data containing the disturbance type.

[0010] Step 5: Using the acquired multi-degree-of-freedom motion attitude of the hull and the corresponding evaluation feature data, the central controller calculates in real time the required hull attitude correction, hull position correction, and the virtual balance force required to maintain the correction.

[0011] Step Six: Based on the layout of the hull's power actuators, the calculated virtual balancing force is dynamically distributed to the corresponding power actuators according to the type of interference using the core distribution strategy. This dynamically suppresses the movement of the hull at the contact point between the measuring probe and the water body within the preset allowable range of measurement error, maximizing the stability of the amphibious equipment under different water flow environments and achieving accurate measurement of water flow.

[0012] Preferably, the types of disturbance include periodic hull rolling caused by swell-dominated conditions, continuous unidirectional thrust caused by jet stream-dominated conditions, and hull up-and-down movement caused by swell and heave-dominated conditions.

[0013] Preferably, the power actuator includes at least two underwater thrusters installed at the bottom of the hull and at least four sets of flight rotors at the top of the hull, each set of flight rotors consisting of two aerial rotors arranged vertically.

[0014] Preferably, the core allocation strategy method includes:

[0015] When the disturbance type is dominated by swells, the underwater thruster is mainly used for differential control to generate phase-compensated reaction force, and the aerial rotor is used for dynamic attitude adjustment.

[0016] When the interference type is dominated by rapid current, the underwater thruster is mainly used to generate continuous thrust for force balance, and the aerial rotor is used to optimize the hydrodynamic shape of the hull.

[0017] When the disturbance type is heave-dominant, compensation is mainly achieved by the downforce or lift generated by the air rotor.

[0018] Preferably, the method for the central controller to calculate the required ship attitude correction, ship position correction, and virtual balance force required to maintain the correction in real time in step five includes the following steps:

[0019] Q1: Define the desired target state and set a desired range value for the motion attitude of each degree of freedom of the ship;

[0020] Q2: Calculate the state deviation, compare the deviation between the current detected value and the expected range value for each degree of freedom of motion of the hull, and output the hull attitude correction amount and the hull position correction amount;

[0021] Q3: Construct a ship dynamics model, integrate a ship motion mathematical model inside the controller, and use the differential equations in the model to output the virtual balance force required to maintain the correction.

[0022] Preferably, the central controller in step five continuously acquiring the multi-degree-of-freedom motion attitude of the hull and the corresponding evaluation characteristic data constitutes a closed-loop control process, which includes:

[0023] Feedforward control uses the predicted data from step three and the current multi-degree-of-freedom motion attitude of the hull to issue control commands in advance.

[0024] Feedback control: Step 2 compares the actual state of the hull monitored in real time with the desired target state to generate feedback compensation commands.

[0025] By combining feedforward and feedback mechanisms, along with built-in adaptive or robust mechanisms, the effects of model uncertainty and measurement noise are eliminated.

[0026] Preferably, the method for detecting whether the hull will exceed a preset stability threshold under the predicted wave force and predicted hydrodynamic disturbance in step four includes the following steps:

[0027] S1: Integrate the predicted wave force with the predicted hydrodynamic disturbance in the same force line direction to form the predicted environmental disturbance force;

[0028] S2: The predicted environmental disturbance force is used as input and injected into the dynamic motion mathematical model of the ship. Starting from the current state of the ship, the motion response of the ship under the action of only the predicted environmental disturbance force and without any active control is calculated in a forward simulation over a period of time in the future. The output is a motion trajectory of each degree of freedom of the ship in the future time.

[0029] S3: Compare the above motion trajectory with the preset stability threshold, traverse every motion quantity during the simulation time, and extract any data where any degree of freedom exceeds the preset stability threshold.

[0030] Preferably, the evaluation feature data includes threat level, the expected most affected degree of freedom of motion, and the predicted start time and duration of the disturbance. The threat level is set according to the magnitude of the distance between the hull degree of freedom and the preset stability threshold in the simulated motion trajectory.

[0031] As a preferred method, the difference between the actual motion of each degree of freedom of the hull and the preset stability threshold is calculated in real time to evaluate the control effect and adjust the control parameters or strategies when the effect is unsatisfactory.

[0032] The system monitors the risk of capsizing and the working status of the actuators in real time. If the system approaches the physical safety limit or working limit, it will enforce the safety plan, including maximum power attitude recovery, issuing an alarm, or instructing the measuring probe to automatically detach.

[0033] Preferably, it also includes a coordination step with the measurement system: when the ship's motion is too large instantaneously, a command is sent to the measurement system to pause sampling or mark data; after reaching a stable state, the measurement system is notified to perform precise data acquisition.

[0034] In summary, the beneficial effects of this invention are:

[0035] This invention revolutionarily solves the industry pain points of traditional rotor-type current meter cableways being easily damaged and unable to operate in medium and high water, and the easy loss of control and bottom tracking failure of mobile ADCP in floods and rapids, by integrating cutting-edge sensing, prediction and active control technologies through an amphibious platform. It can intelligently switch working modes (contact measurement in medium and low water, and non-contact aerial measurement in high water) under all water level conditions. By using the coordinated distribution control of the aerial rotor and underwater thruster, it actively cancels the interference of wind, waves and currents, and stabilizes the measurement attitude within the allowable error range. Thus, it has achieved for the first time a truly safe, accurate and fully automatic all-weather full-range online monitoring of hydrological flow, providing unprecedented reliable data support for flood control and drought relief, water resource management and disaster early warning. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the overall process framework of the method for measuring hydrological flow using amphibious equipment according to the present invention;

[0038] Figure 2 This is a schematic diagram of the overall structure of the amphibious equipment in an embodiment of the method for measuring hydrological flow using amphibious equipment according to the present invention;

[0039] Figure 3 This is a side view of the amphibious equipment in an embodiment of the method for measuring hydrological flow using amphibious equipment according to the present invention.

[0040] Figure 4This is a schematic diagram of the rotor structure of an amphibious device in an embodiment of a method for measuring hydrological flow using amphibious equipment according to the present invention.

[0041] Figure 5 This is a schematic diagram of the rotor-type current meter measuring structure in the method for measuring hydrological flow using amphibious equipment according to the present invention;

[0042] Figure 6 This is a schematic diagram of the structure of the underway ADCP measurement in the method for measuring hydrological flow using amphibious equipment according to the present invention. Detailed Implementation

[0043] The present invention will now be described in further detail with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. These drawings are simplified schematic diagrams, which are only used to illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0044] To facilitate understanding of the present invention, a more complete description of the invention will be given below with reference to the accompanying drawings, which illustrate several embodiments of the invention. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the invention will be more thorough and complete.

[0045] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0046] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features for a similar purpose, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0047] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of at least two elements or the interaction relationship of at least two elements, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0048] Before introducing the implementation examples, it should be noted that the most widely recognized accurate flow measurement methods in the hydrological industry today are rotor flow meter and mobile ADCP measurement method.

[0049] Rotor-type flow meter measurement method

[0050] Rotary current meters are standard velocity measuring instruments used in hydrological surveys. (Reference) Figure 5 Widely used and with a long history, the rotor current meter was first recorded in use in 1943. It works by utilizing the momentum transfer from the water flow to the rotor. When water flows over the rotor, the linear motion energy generates rotor torque. This torque overcomes the rotor's inertia, internal friction from bearings, and fluid resistance caused by the relative motion between the water flow and the rotor, causing the rotor to rotate. The result is relatively simple: within a certain speed range, the rotor speed and the water flow velocity have a simple, approximately linear relationship. Nowadays, rotor current meters can be used to measure flow effectively when mounted on a hydrological cableway system. This system includes the cableway, drive equipment, signal system, recording and control devices (cableway flow measurement control console), and a lead weight. Cableway flow measurement uses a rotor current meter mounted on a lead weight, which is equipped with surface and bottom signals for cableway flow measurement. The cableway system essentially creates an "aerial track" above the river channel. The drive unit, carrying measuring equipment such as a lead weight and a rotor velocity meter, moves above the water surface along a cableway, much like a cable car. During its movement, the flow meter can perform vertical line measurements on the cross-section of the water flow, enabling vertical measurements of the water flow velocity at different locations.

[0051] However, the disadvantages of cableway flow measurement are also very obvious. First, the construction of cableways is very expensive, especially for automated cableways with too many functions. Second, the measurement efficiency of the "plumb line method" is very low and the degree of automation is not high enough. Third, in medium to high water (flow velocity > 1.5 m / s), the rope connecting the cableway and the lead weight is easily broken, and the lead weight will vibrate in floodwaters, which will not meet the conditions for flow measurement and will not be able to achieve flow measurement in medium to high water.

[0052] mobile ADCP

[0053] The underway ADCP, also known as the shipborne ADCP, is referenced. Figure 6Flow measurement is achieved by using an ADCP (Advanced Diffusion Probe) mounted on a mobile unmanned surface vessel (USV). The entire flow measurement system is installed on the mobile vessel to measure water flow velocity and can complete flow measurement while the vessel is in motion. This type of ADCP is convenient and flexible. The equipment can be powered by onboard generators and can monitor flow in real time, offering high real-time performance. This type of ADCP needs to be able to measure the velocity of the vessel. Using the riverbed as a reference, the Doppler frequency shift is obtained by measuring the acoustic signal reflected from the riverbed, thus determining the vessel's velocity—a key indicator of the ADCP system: "bottom tracking" capability. It transmits relatively high power to ensure it can measure sufficiently deep riverbeds and sufficiently strong echo signals.

[0054] However, during the vessel's movement, external natural factors can easily cause the hull to sway, thus affecting the accuracy of instrument measurements; the noise generated by the hull can also interfere with the equipment, leading to inaccurate measurement results. In medium to high water levels, the unmanned vessel is easily struck by floating debris and floodwaters in the river, preventing the hull from moving laterally. The high-resolution, high-frequency acoustic signals it requires are quickly absorbed, making it impossible to measure bottom tracking information and thus failing to meet the requirements for cross-sectional measurements, preventing ADCP from performing independent measurements.

[0055] Please see Figures 1-4 This invention provides an embodiment that solves the problem of flow monitoring during medium-to-high water levels, enabling online measurement of the entire flow range. It offers a more effective measurement method in the face of natural disasters such as excessive flooding. The method utilizes amphibious equipment—with a hull at the bottom and a flight rotor at the top—to measure hydrological flow. The specific steps include the following: (Refer to...) Figure 1 :

[0056] Step 1: Pre-sensing and Status Monitoring

[0057] Real-time acquisition of multi-dimensional water flow velocity vectors around the hull of amphibious equipment; using water flow velocity vector data to infer the wave characteristics of the water flow; and simultaneously acquiring airflow data around the hull to construct the underwater, surface, and above-water environmental force field regions.

[0058] Specifically, the shipborne Doppler current meter (ADCP) is used to acquire the three-dimensional water flow velocity vector around the ship in real time, mainly the direction and speed of the water flow. The wave characteristics are inferred in real time by combining the high-precision inertial measurement unit (IMU) / motion reference unit (MRU) with GNSS attitude data. The shipborne wind speed and direction sensor is used to acquire the direction and strength of the airflow (wind direction and wind speed) around the ship in real time.

[0059] The ship's multi-degree-of-freedom motion attitude, absolute position, angular velocity, and linear acceleration are acquired in real time. The multi-degree-of-freedom motion attitude includes roll angle, pitch angle, bow angle, heave, longitudinal displacement, and lateral displacement.

[0060] Specifically, it integrates high-precision GNSS (dual-antenna RTK / GPS / BeiDou) and inertial measurement unit (IMU) data to acquire the ship's 6-DOF motion attitude (roll, pitch, yaw, heave, surge, and sway) and absolute position in real time and at high frequency (≥10 Hz). It also integrates data from the ship's motion accelerometer, gyroscope, and optical flow module to calculate the ship's angular velocity and linear acceleration.

[0061] Step 2: Forecasting and Threat Assessment

[0062] The water flow velocity vector data is input into a pre-trained prediction model to predict the future water flow direction, velocity change trend and hydrodynamic interference to the ship hull, and the wave feature data is used to predict the wave force of the waves acting on the ship hull position within a set time period.

[0063] Specifically, based on the real-time water flow velocity field data obtained in the first step, a machine learning model (pre-trained) is applied and a fluid dynamics model (a simplified model based on hybrid RANS-LES) is fused to predict the changing trends of flow direction and velocity in the next few seconds and their hydrodynamic interference (resistance and lateral force) on the hull. Based on the real-time wave characteristic data obtained in the first step, wave spectrum analysis algorithms (JONSWAP spectrum, Pierson-Moskowitz spectrum) are applied and combined with a physics-based wave propagation model (simplified Boussinesq equation or phase analysis model) to predict the wave force / moment (amplitude, direction, and phase) acting on the hull position in the next 10-120 seconds.

[0064] Simultaneously, stability thresholds for each degree of freedom motion in the multi-degree-of-freedom motion attitude of the hull are set, such as the maximum allowable roll angle and the maximum allowable displacement deviation. The predicted wave force and predicted hydrodynamic disturbance data are input into the dynamic motion mathematical model of the hull. The dynamic motion mathematical model includes the hydrodynamic coefficient, mass distribution, moment of inertia, etc. Through model simulation calculation or rule base judgment, it is predicted whether the hull will exceed the preset stability threshold under the above predicted disturbance, and the corresponding evaluation feature data is output.

[0065] The assessment feature data includes the type of disturbance, threat level, expected maximum degree of freedom of motion, and predicted start time and duration of the disturbance. The types of disturbance include periodic hull rolling caused by swell dominance, unidirectional continuous thrust caused by jet stream dominance, and hull up-and-down movement caused by swell and heave dominance.

[0066] It is worth mentioning that, in this embodiment, the method for detecting whether the hull will exceed a preset stability threshold under the predicted wave force and predicted hydrodynamic disturbance includes the following steps:

[0067] The predicted wave force and the predicted hydrodynamic disturbance are integrated in the same force line direction to form the predicted environmental disturbance force.

[0068] The predicted environmental disturbance force is used as input and injected into the dynamic motion mathematical model of the ship. Starting from the current state of the ship, the motion response of the ship under the action of only the predicted environmental disturbance force and without any active control is calculated in a forward simulation over a period of time in the future. The output is a motion trajectory of the ship's various degrees of freedom in the future time.

[0069] The above motion trajectory is compared with a preset stability threshold. Every motion quantity during the simulation time is traversed, and data of any degree of freedom that exceeds the preset stability threshold is extracted.

[0070] The threat level is set based on the magnitude of the preset stability threshold distance between the ship's degrees of freedom in the simulated motion trajectory;

[0071] Threat Level: Classified based on the magnitude and duration of predicted movement exceeding a threshold.

[0072] Low: There may be a slight momentary exceedance, but it recovers quickly and does not affect the measurement.

[0073] Medium: Significantly exceeds limits, lasting for several seconds; measurement data needs to be marked; control system needs close monitoring.

[0074] High: Severely exceeding limits, approaching the physical safety boundary, with a risk of overturning or mission failure.

[0075] Step 3: Active Stabilization Control Decision

[0076] By utilizing the acquired multi-degree-of-freedom motion attitude of the hull and the corresponding evaluation feature data, the central controller calculates in real time the required hull attitude correction, hull position correction, and the virtual balancing force required to maintain the correction. Based on the layout of the hull's power actuators, the calculated virtual balancing force is dynamically distributed to the corresponding power actuators according to the type of interference using a core allocation strategy. This dynamically suppresses the hull's motion at the contact point between the measurement probe and the water (especially roll, pitch, heave, and horizontal displacement of the probe position) within the preset measurement error allowable range, maximizing the stability of the amphibious equipment under different water flow environments and achieving accurate measurement of water flow.

[0077] Specifically, based on the current measured hull attitude / displacement and threat assessment results, the central control algorithm on the onboard computer (such as Model Predictive Control (MPC) or PID adaptive controller) calculates in real time the required hull attitude / position correction (Δattitude, Δposition) and the virtual balance force / torque vector (magnitude, direction, point of application) needed to maintain this correction. According to the hull's dynamic layout and dynamic response model, the calculated total virtual balance force / torque vector is optimally decomposed and allocated to 10 available actuators. Figure 2 and Figure 3 The power actuators described therein include two underwater thrusters mounted on the bottom of the hull and four sets of flight rotors on the top of the hull. Each set of flight rotors consists of two vertically arranged aerial rotors. (Refer to...) Figure 4 One of the core allocation strategies includes:

[0078] When the disturbance type is dominated by swell, the differential control of the two mid-mounted underwater thrusters with fast response is mainly relied on to generate reaction force for real-time compensation. Through phase compensation control, the output reaction force and the predicted wave force are basically canceled out in time. At the same time, the dynamic attitude adjustment of the eight air rotors is combined to suppress swaying.

[0079] When the interference type is dominated by rapid current, it mainly relies on two underwater thrusters to generate continuous counter-thrust (force balance), and combines eight air rotors to perform dynamic attitude adjustment (minor adjustment of roll / pitch angle to optimize hydrodynamic shape) to reduce drag or increase stability.

[0080] When the disturbance type is heave-dominant, compensation is achieved by precisely controlling the eight air rotors to generate downforce or lift.

[0081] It should be noted that, in this embodiment, the method by which the central controller calculates in real time the required ship attitude correction, ship position correction, and the virtual balance force required to maintain the correction includes the following steps:

[0082] Define the desired target state and set a desired range value for the motion attitude of each degree of freedom of the ship.

[0083] Calculate the state deviation, compare the deviation between the current detected value and the expected range value for each degree of freedom of motion of the hull, and thus output the hull attitude correction amount and the hull position correction amount;

[0084] Construct a ship dynamics model, integrate a ship motion mathematical model inside the controller, and use the differential equations in the model to output the virtual equilibrium force required to maintain the correction.

[0085] Step 4: Closed-loop execution allocation and state tracking of power:

[0086] Command issuance: The target thrust, which is decomposed into each actuator, is issued to the corresponding underwater thruster controller / rotor controller in real time using PWM.

[0087] Dynamic response of actuators: After receiving the command, each actuator uses its internal ESC electronic speed controller to control the current and generate actual force and torque to act on the hull.

[0088] Real-time status feedback closed loop: The IMU / GNSS system continuously monitors the actual attitude and position of the ship after the response at a high frequency (≥10Hz), while the ADCP / wave sensor / wind direction and speed sensor continuously monitor the real-time changes of environmental interference.

[0089] The ship's central control algorithm continuously receives new measured data on the ship's hull status and environmental disturbances; this is a closed-loop process.

[0090] Feedforward control: Using predicted disturbance information and hull model, commands are issued in advance to compensate for "known" disturbances.

[0091] Feedback control: The measured hull state is compared with the desired target state, the state deviation is calculated, and feedback compensation commands are generated according to the control algorithm (PID, LQR, MPC, etc.) to eliminate the deviation.

[0092] Adaptive / robust mechanism: The algorithm has built-in robustness to handle model uncertainties and measurement noise. It can be equipped with an adaptive module to identify environmental disturbance characteristics or changes in ship hydrodynamic parameters online and adjust control parameters or models.

[0093] Step 5: Stabilization Effect Evaluation and Strategy Adjustment

[0094] The system calculates the difference between the actual motion of each degree of freedom of the hull and the preset stability threshold in real time, evaluates the control effect, and adjusts the control parameters or strategies when the effect is not good. It monitors the risk of hull capsizing and the working status of the actuators. If the hull approaches the physical safety limit or working limit, it will forcibly execute the safety plan, including maximum power attitude recovery, issuing an alarm or commanding the measurement probe to automatically detach.

[0095] Specifically, it includes the following steps:

[0096] Performance index calculation: Real-time calculation of the difference between the actual motion (RMS value) of each degree of freedom of the hull and the preset stability threshold.

[0097] Assessment and Adjustment:

[0098] The central control algorithm continuously evaluates the control effect:

[0099] Good results: Maintains or fine-tunes current control parameters.

[0100] Unsatisfactory results (e.g., actual deviations consistently exceed limits or contact force is too high):

[0101] Check if the prediction model is inaccurate (due to force majeure or severe environmental changes). If the prediction fails, increase the weight of feedback control.

[0102] Check if the control command allocation is reasonable, or if the actuator is saturated or responding abnormally. If saturated, try adjusting the allocation strategy or applying constraints based on priority (stability first).

[0103] Check if the hull model parameters are mismatched. If the mismatch is severe, trigger online parameter identification and controller reconfiguration.

[0104] Abrupt changes in disturbance mode (such as a surge suddenly turning into a jet stream): dynamically adjust controller parameters or switch control strategies.

[0105] Step 6: Task Coordination and Security Boundaries

[0106] Measurement task coordination:

[0107] The entire stabilization system needs to be highly coordinated with the measurement system. For example:

[0108] When the ship's motion is too large instantaneously, a command is sent to the measurement system to pause sampling / temporarily store data / mark suspicious points.

[0109] Once a stable state is reached, the measurement system is notified that precise data acquisition can begin.

[0110] Security boundary monitoring:

[0111] The system continuously monitors the ship's hull status:

[0112] Overturning risk assessment: Real-time calculation of stability height (GM) and overturning moment margin.

[0113] Thruster status monitoring: motor temperature, speed limits, thrust limits, etc.

[0114] Once the system detects that the ship's attitude is approaching its physical safety limits (e.g., the roll angle is close to the flooding angle, or exceeds the capsizing threshold) or that the actuators are exceeding their operating limits (overload, overheating), regardless of the measurement task, the system will forcibly execute the safety contingency plan:

[0115] Automatically enable maximum power attitude recovery.

[0116] If the structure has already overturned, try using the "turtle flip" 180° rotation function to restore its posture.

[0117] Issue alarms and location information, request manual intervention, and maintain regular sound and light alarms.

[0118] In extreme cases, the command measurement probe will automatically detach.

[0119] In actual operation, the amphibious flow measurement equipment (integrating ADCP, IMU, GNSS dual antennas, anemometer, 4 sets of 8 air rotors, and 2 underwater thrusters) was used to complete a continuous 24-hour flow monitoring from low water to high water (simulating a flood process) to verify the full-range measurement capability.

[0120] Scenario 1: Contact measurement under medium to low water conditions (flow velocity < 1.5 m / s)

[0121] Environmental scene description:

[0122] Time: At the start of the mission, during the day, the weather is sunny and there is a light breeze.

[0123] Water level: Low, close to the average water level over the years.

[0124] Flow velocity: The average flow velocity at the cross section is about 1.2 m / s, the water flow is stable, and there are no obvious waves.

[0125] Risk: Low risk, with the main potential disturbances being wake waves or gusts generated by small vessels navigating the waters.

[0126] Specific running example:

[0127] Deployment and startup:

[0128] The amphibious equipment was launched autonomously from the shore-based base station. The central controller was activated, and all sensors began to operate.

[0129] Forward sensing: The shipborne ADCP begins to collect initial flow velocity profile data of the cross section; the IMU / GNSS fusion system provides high-precision position and initial attitude (roll and pitch are close to 0 degrees); the wind speed sensor detects a light breeze (wind speed 2 m / s).

[0130] Crossing section and measurement:

[0131] The equipment received the "Start Measurement" command. The control strategy selected "Surface Navigation Mode", which mainly relies on two underwater thrusters for power, and travels along an "S"-shaped path from one bank to the other like an unmanned boat, while ADCP performs continuous measurements.

[0132] Forecasting and Evaluation (Ongoing):

[0133] Based on the current stable water flow and meteorological data, the large-scale prediction model predicts that the environmental forces (hydrodynamics, wave forces) will change gradually over the next 30 seconds, with a threat level of "low".

[0134] Dynamic model simulations show that all degrees of freedom of the hull motion are well within the stability threshold (e.g., roll angle < ±3°).

[0135] Active stabilization control (fine-tuning):

[0136] Suddenly, the wake of a passing ship appeared. The IMU first detected a slight pitching motion of the ship.

[0137] The predictive model quickly identified this as a "surge-dominated" disturbance caused by small waves and predicted its duration and intensity.

[0138] The central controller (MPC algorithm) immediately calculates that a small counter-compensation torque is needed to counteract this pitching moment.

[0139] Power Distribution: The core power distribution strategy is activated. Due to the relatively small and periodic nature of the interference, the controller primarily instructs the two underwater thrusters to perform differential speed adjustments (one slightly accelerates, the other slightly decelerates), rapidly generating reaction torque to counteract the wave torque. Simultaneously, four of the eight aerial rotors undergo millisecond-level speed fine-tuning to assist in stabilizing the attitude; the entire process is completed within one second.

[0140] Effect assessment: The pitch angle of the hull was suppressed as soon as it began to increase, eventually producing only a small fluctuation of about 1 degree. The ADCP measurement data was not affected in any way and no marking was required.

[0141] Task completed:

[0142] The equipment smoothly completed the crossing of the entire section, and the high-precision ADCP data was transmitted back to the control center in real time. Subsequently, the equipment automatically returned to base or anchored to stand by.

[0143] Scenario 2: Non-contact measurement under medium to high water conditions (flow velocity > 2.5 m / s)

[0144] Environmental scene description:

[0145] Time: 12 hours after the mission began, at night, due to the passage of the flood peak caused by torrential rains upstream.

[0146] Water level: Rising rapidly, exceeding the warning level by 1 meter.

[0147] Flow velocity: The average flow velocity across the cross section increases sharply to 3.0 m / s, with a large amount of weeds, branches and other floating objects floating on the water surface, and wave heights exceeding 0.5 meters.

[0148] Risk: Extremely high risk. Traditional unmanned vessels cannot operate in this environment (they are easily struck and cannot cross currents); ADCP bottom tracking may fail due to excessive suspended debris and water depth.

[0149] Specific running example:

[0150] Mode switching decision:

[0151] Based on the water level warning, the shore-based control center sent "high water flow response instructions" to the amphibious equipment.

[0152] Forward sensing: The equipment's ADCP detected that the flow velocity had far exceeded the safety threshold of 1.5m / s; the optical camera detected a large number of floating objects ahead; and the IMU detected that the hull was shaking more violently due to turbulence.

[0153] Prediction and Threat Assessment:

[0154] The large-scale predictive model integrates jet stream and wave data to determine that future disturbances will be a mixed pattern of "jet stream dominance" and "surge dominance".

[0155] Dynamic model simulations show that if the surface contact mode continues, the threat level is "high": the hull will be swept away rapidly, the lateral displacement (Sway) will be severely exceeded, and a collision with floating objects is very likely to cause equipment damage or capsizing. The ADCP bottom tracking signal has too low a signal-to-noise ratio to lock onto the riverbed.

[0156] Takeoff and hovering:

[0157] The control system immediately implemented the safety plan and terminated the water surface measurement mode.

[0158] Power distribution: All eight air rotors are fully engaged to provide vertical lift, raising the equipment vertically from the water into the air, while the two underwater thrusters are deactivated and retracted into the hull to reduce air resistance.

[0159] The equipment was stably lifted to a predetermined safe height of 15 meters above the water surface (avoiding waves and floating objects).

[0160] Aerial non-contact measurement (hovering method):

[0161] Measurement method transformation: The equipment no longer relies on bottom tracking, but instead uses GNSS precise positioning (RTK mode provides centimeter-level positioning accuracy) to calculate its own absolute movement speed.

[0162] Workflow:

[0163] The equipment flew to the starting point of the section, and the GNSS marked the coordinates of the first measuring point.

[0164] Active Stabilization Control (Core): In the air, the equipment is affected by gusts of wind and its own rotor downwash, and the central controller continues to operate:

[0165] Objective: To strictly control the lateral displacement (Sway) and heave (Heave) of the equipment within ±0.1 meters, and the roll / pitch within ±1°, in order to ensure accurate ADCP beam pointing.

[0166] Execution: The controller calculates attitude deviation in real time using IMU / GNSS data, dynamically adjusts the rotation speed of the eight rotors, and generates precise force and torque to counteract wind disturbance and achieve precise hovering.

[0167] ADCP emits sound waves downwards to measure the velocity profile of the water below. The relative water velocity measured by ADCP needs to be subtracted from the absolute movement speed of the equipment itself provided by GNSS (i.e., "water tracking mode") to obtain the true absolute velocity of the water flow.

[0168] The equipment flies slowly along the cross-section and hovers at multiple predetermined points in sequence to make measurements, which is equivalent to the traditional "vertical line method" but is extremely efficient.

[0169] The predictive model continuously predicts wind shear and gusts, providing feedforward compensation signals to the controller, making stability control more proactive and smoother.

[0170] Security monitoring and task coordination:

[0171] Safety boundary monitoring: The system calculates battery power and motor load in real time. Since hovering in the air consumes a lot of energy, the system predicts the remaining flight time and automatically flies back to the base station when the battery power is below the threshold.

[0172] Task Coordination: When a strong wind causes the equipment's horizontal displacement deviation to approach 0.08 meters, the controller increases the control force output on the one hand, and sends a command to the measurement system on the other hand to mark the ADCP data collected at that moment as "low confidence". After the equipment stabilizes, it will continue to collect "high confidence" data.

[0173] Mission completed and return:

[0174] After completing the aerial measurement of the entire cross section, the equipment will transmit the complete flow data back.

[0175] After the flood peak passed, the water level and flow rate decreased, and the equipment safely landed on the water surface. It then switched back to surface mode and returned to the charging base station for charging and maintenance, preparing for the next mission.

[0176] Amphibious equipment can intelligently adapt to vastly different hydrological environments:

[0177] In low to medium water conditions, as an advanced unmanned survey vessel, it utilizes underwater propulsion and slight aerial assistance to achieve efficient and stable contact measurements.

[0178] During medium to high water levels or floods, it transforms into a precise "measurement drone," avoiding high risks on the water surface through flight. Utilizing GNSS positioning and powerful aerial stabilization capabilities, it achieves non-contact measurement, solving the industry's pain point of being unable to conduct safe and accurate measurements under extreme hydrological conditions, and truly realizing "full-range online measurement."

[0179] In summary, this invention revolutionarily solves the industry pain points of traditional rotor-type current meter cableways being easily damaged and unable to operate in medium and high water conditions, and the easy loss of control and bottom tracking failure of mobile ADCP in floods and rapids, by integrating cutting-edge sensing, prediction and active control technologies through an amphibious platform. It can intelligently switch working modes (contact measurement in medium and low water, and non-contact measurement in the air in high water) under all water level conditions. By using the coordinated distribution control of the air rotor and underwater thruster, it actively cancels the interference of wind, waves and currents, and stabilizes the measurement attitude within the allowable error range. Thus, it has achieved, for the first time, truly safe, accurate and fully automatic all-weather full-range online monitoring of hydrological flow, providing unprecedented reliable data support for flood control and drought relief, water resource management and disaster early warning.

[0180] The above description is merely a specific embodiment of the invention, but the scope of protection of the invention is not limited thereto. Any variations or substitutions conceived without inventive effort should be included within the scope of protection of the invention. Therefore, the scope of protection of the invention should be determined by the scope defined in the claims.

Claims

1. A method of measuring hydrologic flow with amphibious equipment, characterized by: Includes the following steps: Step 1: Real-time acquisition of multi-dimensional water flow velocity vectors around the hull of amphibious equipment; use the water flow velocity vector data to infer the wave characteristics of the water flow; and simultaneously acquire airflow data around the hull to construct the underwater, surface, and above-water environmental force field regions. Step 2: Real-time acquisition of the ship's multi-degree-of-freedom motion attitude, including roll angle, pitch angle, bow angle, heave, longitudinal displacement, and lateral displacement; Step 3: Input the water flow velocity vector data into the pre-trained prediction model to predict the future water flow direction, velocity change trend and hydrodynamic interference to the ship hull, and use the wave feature data to predict the wave force of the waves acting on the ship hull position within the set time. Step 4: Set the stability threshold for each degree of freedom motion in the multi-degree-of-freedom motion attitude of the hull. Input the predicted wave force and predicted hydrodynamic disturbance data into the dynamic motion mathematical model of the hull. Detect whether the hull will exceed the preset stability threshold under the action of the predicted wave force and predicted hydrodynamic disturbance. At the same time, output the corresponding evaluation feature data containing the disturbance type. The evaluation feature data includes the disturbance type, threat level, the expected most affected degree of freedom of motion, and the predicted start time and duration of the disturbance. The disturbance types include periodic hull rolling caused by swell dominance, unidirectional continuous thrust caused by jet stream dominance, and hull up and down movement caused by swell and heave dominance. Step 5: Using the acquired multi-degree-of-freedom motion attitude of the hull and the corresponding evaluation feature data, the central controller calculates in real time the required hull attitude correction, hull position correction, and the virtual balance force required to maintain the correction. Step Six: Based on the layout of the hull's power actuators, the calculated virtual balancing force is dynamically allocated to the corresponding power actuators according to the type of interference using a core allocation strategy. The power actuators include at least two underwater thrusters installed at the bottom of the hull and at least four sets of flight rotors at the top of the hull. Each set of flight rotors consists of two vertically arranged aerial rotors. This dynamically suppresses the hull's movement at the contact point between the measuring probe and the water within a preset allowable measurement error range, maximizing the stability of the amphibious equipment under different water flow environments and achieving accurate measurement of water flow. The core allocation strategy method includes: When the disturbance type is dominated by swells, the underwater thruster is mainly used for differential control to generate phase-compensated reaction force, and the aerial rotor is used for dynamic attitude adjustment. When the interference type is dominated by rapid current, the underwater thruster is mainly used to generate continuous thrust for force balance, and the aerial rotor is used to optimize the hydrodynamic shape of the hull. When the disturbance type is heave-dominant, compensation is mainly achieved by the downforce or lift generated by the air rotor.

2. A method of measuring the flow of water with amphibious equipment according to claim 1, characterized in that: The method for the central controller to calculate the required ship attitude correction, ship position correction, and virtual balance force required to maintain the correction in real time in step five includes the following steps: Q1: Define the desired target state and set a desired range value for the motion attitude of each degree of freedom of the ship; Q2: Calculate the state deviation, compare the deviation between the current detected value and the expected range value for each degree of freedom of motion of the hull, and output the hull attitude correction amount and the hull position correction amount; Q3: Construct a ship dynamics model, integrate a ship motion mathematical model inside the controller, and use the differential equations in the model to output the virtual balance force required to maintain the correction.

3. A method of measuring the flow of water with amphibious equipment according to claim 2, characterized in that: The central controller in step five continuously acquires the ship's multi-degree-of-freedom motion attitude and corresponding evaluation characteristic data, which is a closed-loop control process, including: Feedforward control uses the predicted data from step three and the current multi-degree-of-freedom motion attitude of the hull to issue control commands in advance. Feedback control involves comparing the actual state of the hull monitored in real time with the desired target state in step two, and generating feedback compensation commands.

4. The method for measuring hydrological flow using amphibious equipment according to claim 1, characterized in that: The method for detecting whether the ship's hull will exceed the preset stability threshold under the predicted wave force and predicted hydrodynamic disturbance in step four includes the following steps: S1: Integrate the predicted wave force with the predicted hydrodynamic disturbance in the same force line direction to form the predicted environmental disturbance force; S2: The predicted environmental disturbance force is used as input and injected into the dynamic motion mathematical model of the ship. Starting from the current state of the ship, the motion response of the ship under the action of only the predicted environmental disturbance force and without any active control is calculated in a forward simulation over a period of time in the future. The output is a motion trajectory of each degree of freedom of the ship in the future time. S3: Compare the above motion trajectory with the preset stability threshold, traverse every motion quantity during the simulation time, and extract any data where any degree of freedom exceeds the preset stability threshold.

5. The method for measuring hydrological flow using amphibious equipment according to claim 4, characterized in that: The assessment feature data includes threat level, the expected most affected degrees of freedom of motion, and the predicted start time and duration of the disturbance. The threat level is set according to the magnitude of the distance between the ship's degrees of freedom and the preset stability threshold in the simulated motion trajectory.

6. The method for measuring hydrological flow using amphibious equipment according to claim 1, characterized in that: The difference between the actual motion of each degree of freedom of the hull and the preset stability threshold is calculated in real time to evaluate the control effect and adjust the control parameters or strategies when the actual deviation continues to exceed the limit or the contact force is too large. The system monitors the risk of capsizing and the working status of the actuators in real time. If the system approaches the physical safety limit or working limit, it will enforce the safety plan, including maximum power attitude recovery, issuing an alarm, or instructing the measuring probe to automatically detach.

7. The method for measuring hydrological flow using amphibious equipment according to claim 1, characterized in that: It also includes coordination steps with the measurement system: when the ship's motion is too large instantaneously, it sends a command to the measurement system to pause sampling or mark data; after reaching a stable state, it notifies the measurement system to perform precise data acquisition.

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