Underwater glider ocean collaborative visual simulation system based on digital twinning

Abstract

The invention discloses an underwater glider ocean collaborative visual simulation system based on digital twinning. The underwater glider ocean collaborative visual simulation system comprises an ocean flow field setting module, a motion control module, an ocean current action mechanism module, a digital twinning module and a visualization module. The ocean flow field setting module is used for constructing a virtual ocean simulation environment, the motion control module is used for carrying out motion control on an underwater glider, and the ocean current action mechanism module is used for obtaining a motion track of the underwater glider; the digital twin module is used for simulating the complete profile of the underwater glider according to the adjustment amount of the rolling rudder angle output by the course angle compensation unit and the floating instruction output by the depth setting event trigger controller; and the visualization module is used for displaying the three-dimensional coordinates and the movement track of the underwater glider. According to the ocean collaborative visual simulation system for the underwater glider, the multi-dimensional coupling disturbance action mechanism of ocean current on the speed and attitude of the underwater glider is accurately simulated, and the simulation modeling precision of the underwater glider in a complex ocean environment is remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of computer simulation, and particularly relates to an underwater glider marine cooperative visual simulation system based on digital twinning. BACKGROUND

[0002] As a typical environmental observation equipment in the field of marine unmanned observation, the underwater glider can be equipped with multiple sensors, relies on static buoyancy as driving force, has long endurance, small energy consumption, easy deployment and wide coverage, and plays an important role in marine observation tasks such as marine data collection and underwater infrastructure inspection and maintenance. However, the underwater glider is in the water for a long time during operation, and due to the complexity and uncertainty of the marine environment, the device operation state cannot be fed back in real time during the movement of the underwater glider. Influenced by factors such as device deployment, observation area and real-time sea conditions, the observation difficulty will be further intensified. In order to solve this problem, researchers usually model the movement process and disturbance mechanism of the underwater glider, and use simulation technology to test and evaluate the control and planning strategy under specific environmental disturbance, so as to improve the robustness of the device during movement.

[0003] Although the existing simulation and control technology solves the problem of autonomous cooperative control and decision-making of the underwater glider to some extent, there are still some deficiencies, which are as follows:

[0004] (1) The underwater glider is mainly affected by ocean current disturbance during movement, and the speed and attitude are coupled and disturbed due to the change of time, running speed and position, so the disturbance simulation is difficult.

[0005] (2) The existing simulation method is mostly for underwater glider motion control simulation under single profile and specific scene, and it is difficult to realize simulation algorithm verification under complex scene of long-endurance multi-body formation of the underwater glider.

[0006] (3) The existing simulation platform has low degree of modularity and poor expansibility, and cannot adapt to diversified strategy verification demand. SUMMARY

[0007] In view of the deficiencies of the prior art, the present application aims to provide an underwater glider marine cooperative visual simulation system based on digital twinning, which simulates the real underwater glider marine environment monitoring task scene, and solves the algorithm simulation verification problem of autonomous decision-making and cooperative control of the underwater glider.

[0008] The present application is realized by the following technical solutions.

[0009] An underwater glider marine cooperative visual simulation system based on digital twinning, comprising: an ocean flow field setting module, a motion control module, a digital twinning module and a visualization module.

[0010] The motion control module comprises a feedforward controller, a six-degree-of-freedom rigid body dynamics model, a first calculation module, a six-degree-of-freedom rigid body kinematics model, a second calculation module, a heading angle compensation unit and a depth-holding event trigger controller, wherein the input of the feedforward controller is the motion expectation of the underwater glider in diving or the motion expectation of the underwater glider in ascending, the motion expectation is the velocity V s and the glide angle ξ s , the input of the feedforward controller is the motion expectation of the underwater glider in diving when the underwater glider receives a diving instruction, the input of the feedforward controller is the motion expectation of the underwater glider in ascending when the underwater glider receives an ascending instruction, the output of the feedforward controller is the expected oil tank added mass m bs of the underwater glider and the expected elevator amount r p1s of the underwater glider;

[0011] The input of the six-degree-of-freedom rigid body dynamics model is the oil tank added mass m bs , the expected elevator amount r p1s , the underwater glider state η at the current time and the time interval Δt, and the output of the six-degree-of-freedom rigid body dynamics model is the increment of the linear velocity vector of the underwater glider in the time interval Δt and the increment of the angular velocity vector

[0012] The first calculation module integrates the increment of the linear velocity vector and the increment of the angular velocity vector in the time interval Δt respectively, and obtains the linear velocity vector V(t+Δt) and the angular velocity vector Ω(t+Δt) in turn, and updates the underwater glider state η;

[0013] The input of the six-degree-of-freedom rigid body kinematics model is the underwater glider state η updated by the first calculation module, the current position flow velocity vector V f (μ1,t) in the inertial coordinate system at the time t and the time interval Δt, and the output of the six-degree-of-freedom rigid body kinematics model is the increment of the current position of the underwater glider in the inertial coordinate system in the time interval Δt and the increment of the Euler angle of the underwater glider in the inertial coordinate system

[0014] The second calculation module integrates the increment of the position and the increment of the Euler angle in the time interval Δt respectively, and obtains the updated position μ1(t+Δt) and the updated Euler angle μ2(t+Δt) in turn, and updates the underwater glider state η;

[0015] The target heading angle ψ targetand updating the yaw angle in the Euler angle μ2(t+Δt) as the input of the heading angle compensation unit, the heading angle compensation unit adjusts the yaw angle of the underwater glider, and the output of the heading angle compensation unit is the adjustment amount of the roll rudder angle;

[0016] The depth event trigger controller monitors the diving depth Z in the updated position μ1(t+Δt) of the underwater glider, and when the diving depth Z is greater than or equal to the maximum diving depth Z max of the underwater glider, the depth event trigger controller outputs the floating instruction, the floating instruction makes the input of the feedforward controller the motion expectation of floating, and then the underwater glider performs the floating motion; and the underwater glider floats to the water surface, and the profile motion is completed;

[0017] The ocean flow field setting module constructs the ocean flow field;

[0018] The digital twin module performs the complete profile simulation of the underwater glider according to the adjustment amount of the roll rudder angle output by the heading angle compensation unit and the floating instruction output by the depth event trigger controller, to obtain the profile motion trajectory;

[0019] The visualization module constructs a two-dimensional interface and a three-dimensional interface, wherein the two-dimensional interface is used to display the coordinate position of the underwater glider in a two-dimensional map, and the three-dimensional interface is used to display the profile motion trajectory of the underwater glider in a three-dimensional map.

[0020] In the above technical solution, the state η is defined as:

[0021]

[0022] Wherein μ1=[X,Y,Z] T represents the position component of the underwater glider in the inertial coordinate system, represents the Euler angle of the underwater glider in the body coordinate system, V=[u,v,w] T is the velocity component of the underwater glider in the body coordinate system, Ω=[p,q,r] T represents the angular velocity component of the underwater glider in the body coordinate system.

[0023] In the above technical solution, the ocean flow field setting module adopts a data-driven modal method or a function construction modal method to construct the ocean flow field.

[0024] In the above technical solution, the ocean flow field setting module adopts a data-driven modal method to construct the ocean flow field: taking the ocean current velocity vector of the three-dimensional coordinate point of the task area in the inertial coordinate system at different times as the ocean flow field;

[0025] Adopting a function construction modal method to construct the ocean flow field: selecting a flow velocity distribution function in a flow field function library as needed to construct the ocean flow field, or a user-defined flow velocity distribution function as the ocean flow field.

[0026] Any one periodic function in the flow field function library is:

[0027]

[0028] In the formula, V f (μ1,t) is the current flow velocity vector of μ1 in the inertial coordinate system at t, is the flow field function amplitude, ω is the angular frequency, and ε is the phase angle of the underwater glider.

[0029] In the above technical solution, the ocean collaborative visual simulation system of the underwater glider based on digital twinning further comprises: a current action mechanism module, which calculates the current action force F f and the moment M f of the underwater glider at the current position.

[0030]

[0031] In the formula, is the generalized inertia matrix of the underwater glider, and the current velocity v f (μ1,t) is obtained according to the current flow velocity vector V f (μ1,t), is the cross multiplication operator.

[0032] In the above technical solution, the feedforward controller obtains the oil bag additional mass m bs and the expected elevator amount r p1s through the following formula:

[0033]

[0034] θ s = ξ s - α s

[0035] u s = V s cos α s

[0036] w s = V s sin α s

[0037]

[0038]

[0039] wherein α s is the steady-state attack angle, θ s is the expected pitch angle, g is the gravitational acceleration, K L0K L K D0 K D K m is the viscous hydrodynamic coefficient, M f1 is the added mass coefficient of the underwater glider along b1 direction in the body coordinate system, M f3 is the added mass coefficient of the underwater glider along b3 direction in the body coordinate system, u s is the expected velocity component of the underwater glider along b1 direction in the body coordinate system, w s is the expected velocity component of the underwater glider along b3 direction in the body coordinate system, r h1 is the distance component of the underwater glider's hull center of mass to the buoyancy center along b1 direction in the body coordinate system, r h3 is the distance component of the underwater glider's hull center of mass to the buoyancy center along b3 direction in the body coordinate system, m p is the mass of the movable mass block inside the underwater glider, m h denotes the mass of the underwater glider's hull.

[0040] In the above technical solution, the differential equation of the six-degree-of-freedom rigid body dynamics model is:

[0041]

[0042] wherein M is the generalized mass matrix of the underwater glider, P is the momentum of the underwater glider in the body coordinate system, ∏ is the angular momentum of the underwater glider in the body coordinate system, is the velocity transfer inverse matrix, r h = [r h1 , r h2 , r h3 ] T is the component of the underwater glider's hull center of mass to the buoyancy center in the body coordinate system, r b = [r b1 , r b2 , r b3 ] T is the component of the underwater glider's oil tank center of mass to the buoyancy center, r p = [r p1 + r px , R p sinγ, R p cosγ] T is the component of the underwater glider's movable mass block center of mass to the buoyancy center, r p1 is the actual elevator amount, r px is the distance of the movable mass block along the fuselage direction from the buoyancy center, R p denotes the eccentricity of the movable mass block, γ denotes the roll rudder angle of the movable mass block, m b is the actual oil tank added mass, Fv and M v is the viscous hydrodynamic force and moment in the underwater glider body coordinate system, F f is the current position underwater glider current force, which is calculated by the current action mechanism module; M f is the moment of the current position underwater glider current force.

[0043] In the above technical solution, the differential equation of the six-degree-of-freedom rigid body kinematics model is:

[0044]

[0045]

[0046] In the formula, R eb is the velocity transfer matrix of the underwater glider, I eb is the attitude transfer matrix of the underwater glider, wherein the velocity transfer matrix R eb and the attitude transfer matrix I eb are calculated according to the Euler angle μ2(t) of the underwater glider at time t, is the increment of the x coordinate in the inertial coordinate system within the time interval Δt, is the increment of the y coordinate in the inertial coordinate system within the time interval Δt, is the increment of the z coordinate in the inertial coordinate system within the time interval Δt, is the increment of the roll angle of the underwater glider in the inertial coordinate system, is the increment of the pitch angle of the underwater glider in the inertial coordinate system, is the increment of the yaw angle of the underwater glider in the inertial coordinate system.

[0047] In the above technical solution, the heading angle compensation unit adjusts the yaw angle of the underwater glider by using a deviation threshold trigger or a cumulative time trigger.

[0048] In the above technical solution, the deviation threshold trigger is that when the error between the yaw angle and the target heading angle ψ target is greater than or equal to the deviation threshold, the heading angle compensation unit adjusts the yaw angle of the underwater glider; the cumulative time trigger is that every time interval a time threshold, the heading angle compensation unit adjusts the yaw angle of the underwater glider; and the method for the heading angle compensation unit to adjust the yaw angle of the underwater glider is to adjust the roll rudder angle so that the error between the yaw angle and the target heading angle ψ target tends to zero.

[0049] In the above technical solution, the calculation formula of the target heading angle ψ target is as follows:

[0050]

[0051] wherein (x p ,y p ) is the current position coordinate of the underwater glider, and (x i ,y i ) is the waypoint coordinate input by the digital twin module.

[0052] The underwater glider ocean collaborative visual simulation system of the present application has the following beneficial effects due to the above technical solutions:

[0053] 1. The underwater glider ocean collaborative visual simulation system of the present application can generate or import real ocean data to construct an ocean flow field, accurately simulate the multi-dimensional coupling disturbance mechanism of ocean current on the speed and attitude of the underwater glider, and significantly improve the simulation modeling accuracy of the underwater glider in complex ocean environments.

[0054] 2. The underwater glider ocean collaborative visual simulation system of the present application can solve the complex scene simulation difficulty of long-time flight and multi-body formation of the underwater glider by embedding a parameter-adaptive six-degree-of-freedom rigid body dynamics model, combining the ocean simulation environment based on digital twin, and realizing the simulation control of the underwater glider single profile motion through the task deployment and planning method.

[0055] 3. The underwater glider ocean collaborative visual simulation system of the present application can solve the problem of low modularization and poor expandability by hierarchical decoupling architecture design to realize the expandability and iteration of functional modules, support the independent development and plug-and-play replacement of the motion control module, ocean flow field setting module and digital twin module, allow users to quickly deploy heterogeneous underwater glider models and customize environmental disturbance modes, and realize flexible construction and strategy expansion of multi-type collaborative scenarios through an open task planning interface (waypoint setting, underwater glider model configuration) and heterogeneous task adaptation mechanism. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 Fig. 1 is an architectural diagram of the underwater glider ocean collaborative visual simulation system of the present application;

[0057] Figure 2 Fig. 3 is a flowchart of the motion control module;

[0058] Figure 3 Fig. 4 is a schematic diagram of the motion trajectory of the underwater glider single profile simulation. DETAILED DESCRIPTION

[0059] The technical solutions of the present application will be described in detail below in combination with the drawings and examples.

[0060] In the following embodiment, the inertial coordinate system is defined as the English coordinate system O{x, y, z}, where the positive direction of the x-axis points from due west to due east, the positive direction of the y-axis points from due south to due north, the z-axis is perpendicular to the xOy plane, and the positive direction of the z-axis points in the direction of increasing ocean depth; the body coordinate system B{b1, b2, b3}, where the origin B of the body coordinate system is located at the center of gravity of the underwater glider, b1 points from the origin B to the direction of the underwater glider's nose, b2 points from the origin B to the direction of the left wing, and b3 is perpendicular to the b1Bb2 plane, and the positive direction of b3 points in the direction of increasing ocean depth.

[0061] Example 1

[0062] like Figure 1 As shown, a digital twin-based underwater glider ocean collaborative visual simulation system includes: an ocean flow field setting module, a motion control module, an ocean current action mechanism module, a digital twin module and a visualization module;

[0063] like Figure 2 As shown, the motion control module includes: a feedforward controller, a six-degree-of-freedom rigid body dynamics model, a first calculation module, a six-degree-of-freedom rigid body kinematics model, a second calculation module, a heading angle compensation unit and a depth event trigger controller, wherein the input of the feedforward controller is the underwater glider's diving motion expectation or the upward motion expectation, and the motion expectation is the speed V s and glide inclination ξ s When the underwater glider receives a dive command, the input of the feedforward controller is the desired dive motion (the dive command is input to the underwater glider when it is on the water surface). When the underwater glider receives a float command, the input of the feedforward controller is the desired float motion. The output of the feedforward controller is the desired oil bag additional mass m of the underwater glider. bs and the desired pitch steering amount r of the underwater glider p1s ;

[0064] The feedforward controller calculates the oil bag additional mass m through the following formula: bs and the desired pitch rudder r p1s :

[0065]

[0066] θ s =ξ s -α s

[0067] u s =V s cosα s

[0068] w s =V s sinα s

[0069]

[0070]

[0071] where α s is the steady-state angle of attack, θ s is the desired pitch angle, g is the gravitational acceleration, K L0 , K L , K D0 , K D , K m is the viscous hydrodynamic coefficient (Zhang S, Yu J, Zhang A, et al. Spiraling motion of underwater gliders: Modeling, analysis, and experimental Results [J]. Ocean Engineering, 2013, 60: 1-13.), M f1 is the added mass coefficient of the underwater glider along b1 in the body coordinate system, M f3 is the added mass coefficient of the underwater glider along b3 in the body coordinate system (Zhang S, Yu J, Zhang A, et al. Spiraling motion of underwater gliders: Modeling, analysis, and experimental Results [J]. Ocean Engineering, 2013, 60: 1-13.), u s is the desired velocity component of the underwater glider along b1 in the body coordinate system, w s is the desired velocity component of the underwater glider along b3 in the body coordinate system, r h1 is the distance from the center of mass of the underwater glider to the center of buoyancy along b1 in the body coordinate system, r h3 is the distance from the center of mass of the underwater glider to the center of buoyancy along b3 in the body coordinate system, m p is the mass of the movable mass inside the underwater glider, m h denotes the hull mass of the underwater glider.

[0072] where the viscous hydrodynamic coefficient (K L0 , K L , K D0 , K D , K m ), the added mass coefficient (M f1 , M f3 ), m r , and mh The underwater glider model is determined by the underwater glider type.

[0073] The input of the six-degree-of-freedom rigid body dynamics model is: the oil tank added mass m bs , the expected rudder amount r p1s , the underwater glider state η at the current time (the initial η is defined by the system) and the time interval Δt, and the output of the six-degree-of-freedom rigid body dynamics model is: the increment of the underwater glider linear velocity vector in the time interval Δt and the increment of the rotation angular velocity vector The underwater glider state η is defined as:

[0074]

[0075] Wherein μ1 = [X, Y, Z] T represents the position components of the underwater glider in the inertial coordinate system, X is the x-axis coordinate of the underwater glider in the inertial coordinate system, Y is the y-axis coordinate of the underwater glider in the inertial coordinate system, Z is the z-axis coordinate of the underwater glider in the inertial coordinate system, represents the Euler angles of the underwater glider in the inertial coordinate system, is the roll angle of the underwater glider in the inertial coordinate system, θ is the pitch angle of the underwater glider in the inertial coordinate system, ψ is the yaw angle of the underwater glider in the inertial coordinate system, V = [u, v, w] T is the velocity component of the underwater glider in the body coordinate system, u is the velocity component of the underwater glider along the b1 axis in the body coordinate system, v is the velocity component of the underwater glider along the b2 axis in the body coordinate system, w is the velocity component of the underwater glider along the b3 axis in the body coordinate system, Ω = [p, q, r] T represents the angular velocity component of the underwater glider in the body coordinate system, p is the angular velocity component of the underwater glider along the b1 axis in the body coordinate system, q is the angular velocity component of the underwater glider along the b2 axis in the body coordinate system, r is the angular velocity component of the underwater glider along the b3 axis in the body coordinate system.

[0076] The differential equation of the six-degree-of-freedom rigid body dynamics model is:

[0077]

[0078] Wherein M is the generalized mass matrix of the underwater glider, P is the momentum of the underwater glider in the body coordinate system, Π is the angular momentum of the underwater glider in the body coordinate system, is the velocity transfer inverse matrix, r h = [r h1 , r h2 , r h3 ] Tr is the component of the distance from the center of mass of the hull of the underwater glider to the center of buoyancy in the body coordinate system, r b = [r b1 , r b2 , r b3 ] T r is the component of the distance from the center of mass of the oil tank of the underwater glider to the center of buoyancy, r p = [r p1 + r px , R p sin γ, R p cos γ] T r is the component of the distance from the center of mass of the movable mass of the underwater glider to the center of buoyancy, r p1 r is the actual elevator amount, r px R is the distance from the movable mass to the center of buoyancy in the direction of the fuselage, R p γ represents the roll rudder angle of the movable mass, m b F is the actual oil tank added mass, F v and M v are the viscous hydrodynamic force and moment in the body coordinate system of the underwater glider, the viscous hydrodynamic force F v is calculated according to the oil tank added mass m bs , the desired elevator amount r p1s (Evaluation of energy consumption and motion accuracy for underwater gliders based on quadrant analysis, Yang Song, Ocean Engineering, Volume 285, Part 2), is the cross multiplication operator, F f is the current position underwater glider current force, calculated by the current action mechanism module; M f is the moment of the current position underwater glider current force, calculated by the current action mechanism module.

[0079] The first calculation module integrates the increments of the translational linear velocity vector and the increments of the rotational angular velocity vector in the time interval Δt, respectively, to obtain the translational linear velocity vector V(t+Δt) and the rotational angular velocity vector Ω(t+Δt), and updates the underwater glider state η;

[0080] The input of the six-degree-of-freedom rigid body kinematics model is: the underwater glider state η updated by the first calculation module, the current position current velocity vector V fand time interval Δt, the output of the six-degree-of-freedom rigid body kinematics model is: the increment of the current position of the underwater glider in the inertial coordinate system within the time interval Δt and the increment of the Euler angle of the underwater glider in the inertial coordinate system

[0081] The differential equation of the six-degree-of-freedom rigid body kinematics model is:

[0082]

[0083]

[0084] wherein, R eb is the velocity transfer matrix of the underwater glider, I eb is the attitude transfer matrix of the underwater glider. Wherein, the velocity transfer matrix R eb and the attitude transfer matrix I eb is calculated according to the Euler angle μ2(t) of the underwater glider at time t (J. Cao, J. Cao, B. Yao and L. Lian, "Three dimensional model, hydrodynamics analysis and motion simulation of an underwater glider," OCEANS2015-Genova, Genova, Italy, 2015, pp. 1-8, doi: 10.1109 / OCEANS-Genova.2015.7271365.), is the increment of the x coordinate in the inertial coordinate system within the time interval Δt, is the increment of the y coordinate in the inertial coordinate system within the time interval Δt, is the increment of the z coordinate in the inertial coordinate system within the time interval Δt, is the increment of the roll angle of the underwater glider in the inertial coordinate system, is the increment of the pitch angle of the underwater glider in the inertial coordinate system, is the increment of the yaw angle of the underwater glider in the inertial coordinate system.

[0085] The second calculation module integrates the increment of the position and the increment of the Euler angle within the time interval Δt, respectively, to obtain the updated position μ1(t+Δt) and the updated Euler angle μ2(t+Δt) in turn, and the updated underwater glider state η;

[0086] The target heading angle ψ targetand updating the yaw angle in the Euler angle μ2(t+Δt) as the input of the heading angle compensation unit, the heading angle compensation unit adjusts the yaw angle of the underwater glider according to the yaw angle in the updated Euler angle μ2(t+Δt) and the target heading angle ψ target The heading angle compensation unit outputs the adjustment amount of the roll rudder angle.

[0087] Wherein, the target heading angle ψ target The calculation formula is as follows:

[0088]

[0089] In the formula, (x p ,y p ) is the current position coordinate of the underwater glider, and (x i ,y i ) is the waypoint coordinate input by the digital twin module.

[0090] The deviation threshold trigger is that when the error between the yaw angle and the target heading angle ψ target is greater than or equal to the deviation threshold, the heading angle compensation unit adjusts the yaw angle of the underwater glider; the cumulative time trigger is that every interval of a time threshold, the heading angle compensation unit adjusts the yaw angle of the underwater glider; the method of the above heading angle compensation unit adjusting the yaw angle of the underwater glider is to adjust the roll rudder angle to make the error between the yaw angle and the target heading angle ψ target tend to zero.

[0091] The depth setting event trigger controller monitors the diving depth Z in the updated position μ1(t+Δt) of the underwater glider, and when the diving depth Z is greater than or equal to the maximum diving depth Z max of the underwater glider, the depth setting event trigger controller outputs the floating instruction, the floating instruction makes the input of the feedforward controller be the movement expectation of floating, and then makes the underwater glider perform the floating movement. When the underwater glider floats to the water surface (the depth is 0), the calculation of the underwater glider dynamics and kinematics of the current section is stopped, and the section movement is completed.

[0092] The ocean flow field setting module is used to build a virtual ocean simulation environment, and the ocean flow field setting module uses a data-driven modal method or a function construction modal method to build the ocean flow field. Wherein, the ocean flow field is constructed by using the data-driven modal method: the ocean flow velocity vector of the three-dimensional coordinate point of the task area in the inertial coordinate system at different times is taken as the ocean flow field.

[0093] The ocean flow field is constructed by using the function construction modal method: the ocean flow field is constructed by selecting the flow velocity distribution function in the flow field function library as needed, or the user defines the flow velocity distribution function as the ocean flow field. Wherein, any periodic function in the flow field function library is:

[0094]

[0095] wherein V f (μ1,t) is the current position of the underwater glider in the body coordinate system at time t, is the amplitude of the flow field function, ω is the angular frequency, and ε is the phase angle of the underwater glider (the phase angle ε is a known parameter and remains unchanged).

[0096] The ocean current action mechanism module is used to enable the underwater glider to interact with the virtual marine simulation environment in motion. The ocean current action mechanism module calculates the ocean current action force F f and the moment M f of the underwater glider at the current position according to the ocean current velocity v f (μ1,t) at the three-dimensional coordinate of the current position of the underwater glider in the body coordinate system at time t, which is obtained according to the ocean current velocity vector V f (μ1,t) in the inertial coordinate system. f ;

[0097]

[0098] wherein, is the generalized inertia matrix of the underwater glider.

[0099] The digital twin module defines the task area of the underwater glider in the ocean flow field set by the ocean flow field setting module, sets the number and type of the underwater glider, sets the route (generates the route according to the set starting point coordinates (x A ,y A ) and end point coordinates (x B ,y B ), and the underwater glider sails according to the set route), and calculates the yaw distance d p ; determines the viscous hydrodynamic coefficients, the added mass coefficients, m p , m h , and other related coefficients of the underwater glider according to the type of the underwater glider.

[0100] wherein, the yaw distance d p is used as an evaluation index for the motion simulation of the underwater glider, the yaw distance d p between the current position coordinates (x p ,y p ) of the underwater glider and the route is calculated, and the yaw distance d p is calculated according to the following formula:

[0101]

[0102] The digital twin module performs underwater glider full profile simulation according to the adjustment amount of the roll rudder angle output by the heading angle compensation unit and the floating up instruction output by the depth setting event trigger controller, and obtains a profile motion trajectory.

[0103] The visualization module constructs a two-dimensional interface and a three-dimensional interface through a geographic information system platform. The two-dimensional interface is used to display the coordinate position of the underwater glider in a two-dimensional map, and the three-dimensional interface is used to display the profile motion trajectory of the underwater glider in a three-dimensional map.

[0104] Embodiment 2

[0105] The underwater glider ocean collaborative visual simulation system of embodiment 1 is used to simulate a single underwater glider performing a cross-thermocline observation task, including:

[0106] S1, in the digital twin module, a task area is delimited, the number of underwater gliders is set to 1, the starting point coordinates of the route are set to A (17.65°N, 112.5°E), and the end point coordinates are set to B (18°N, 113.1°E);

[0107] In the ocean flow field setting module, the ocean flow field is constructed by using a function construction modal method, the amplitude is set to 0.6, the angular frequency ω is set to 1.45×10 -4 rad / s, and the phase angle ε is set to π / 2.

[0108] S2, the underwater glider is placed at the starting coordinates, and the initial Euler angle μ2 is set to 0°;

[0109] The diving speed V s of the underwater glider is set to 0.4 m / s, the floating speed V s is set to 0.4 m / s, the diving glide angle ξ s is set to -19.7°, the floating glide angle ξ s is set to 23.1°, the maximum diving depth Z max of the underwater glider is set to 900 m;

[0110] In the heading angle compensation unit, the actual heading angle of the underwater glider is adjusted by using cumulative time triggering, and the maximum value of the cumulative time is set to 200 s;

[0111] S3, the simulation task is simulated:

[0112] The waypoint coordinates are set, and the target heading angle ψ target is calculated according to the waypoint coordinates; the calculated target heading angle ψ target , the set diving speed V s , the floating speed V s , the diving glide angle ξ s, the gliding angle of the upward floating s and the set maximum diving depth Z max Input into the motion control module, the motion control of the underwater glider, according to the ocean current field in the ocean current action mechanism module, the actual velocity vector of the underwater glider is calculated and obtained, and then the profile motion trajectory of the underwater glider is obtained through the digital twin module;

[0113] After the complete profile simulation calculation is completed, the profile motion trajectory is displayed on the three-dimensional interface, the coordinate position of the underwater glider is updated on the two-dimensional interface, and the calculated yaw distance is displayed; adjust the navigation point, run the profile again; repeat the above steps until the underwater glider runs to the vicinity of the end point of the navigation line, record the profile running times and the average yaw distance, and comprehensively evaluate and analyze the cross-thermocline observation task of the underwater glider, and end the simulation.

[0114] In this embodiment, the model of the underwater glider is Haiyan L, and the related parameters of the underwater glider of Haiyan L are described in detail in “Solution of precise added mass of underwater glider and dynamics analysis”, and the simulation data obtained by using Haiyan L for simulation control are as shown in Figure 3 The simulation data includes: single profile motion trajectory, pitch angle, Figure 3 In the simulation data, “Model Z” represents the single profile depth motion trajectory of the underwater glider obtained by the motion control module, “Data Z” represents the actual single profile depth motion trajectory of the underwater glider, “Model θ (x5°)” represents the pitch angle of the underwater glider changing with time t obtained by the motion control module, and “Data θ (x5°)” represents the actual pitch angle of the underwater glider changing with time t, wherein the actual single profile depth motion trajectory and the actual pitch angle are the single profile onboard measured data of Haiyan L underwater glider obtained in the sea trial in May 2023.

[0115] According to Figure 3 The calculation can obtain that the depth standard mean square error between the single profile motion trajectory and the actual single profile depth motion trajectory is 0.052, and the depth standard mean square error between the pitch angle and the actual pitch angle is 0.0601, so that the underwater glider ocean collaborative visual simulation system of the application realizes high-precision motion simulation of the underwater glider under single profile.

[0116] Embodiment 3

[0117] A simulation control method for an underwater glider observation task, which is basically the same as embodiment 2, the only difference is that the underwater glider ocean collaborative visual simulation system of embodiment 1 is used to simulate 9 underwater gliders simultaneously executing distributed cooperative observation tasks.

[0118] The geographic range of the task area is 113.0° to 114° east longitude and 12.5° to 13° north latitude, 9 underwater gliders are randomly placed in the task area, and the initial heading is random; in the ocean current field setting module, the data-driven mode method is used to construct the ocean current field; in the ocean current action mechanism module, the actual speed vector of the underwater glider is obtained; in the heading angle compensation unit, the actual heading angle of the underwater glider is adjusted by using a deviation threshold trigger, and the deviation threshold is set to 5°;

[0119] For each underwater glider in the task area, a task target observation point is set, the starting point coordinates are selected as the midpoint of the three-equal-division grid in the task area, and the nearest underwater glider is allocated to the target observation point according to the nearest principle. 9 underwater gliders can obtain high-precision motion simulation consistent with embodiment 2 under a single profile.

[0120] The above is an exemplary description of the present application, it should be noted that without departing from the core of the present application, any simple modification, modification or other equivalent replacement which can not cost the creative labor of those skilled in the art falls within the protection scope of the present application.

Claims

1. A digital twin-based underwater glider ocean collaborative visual simulation system, characterized by: include: Ocean flow field setting module, motion control module, digital twin module and visualization module; The motion control module includes: a feedforward controller, a six-degree-of-freedom rigid body dynamics model, a first calculation module, a six-degree-of-freedom rigid body kinematics model, a second calculation module, a heading angle compensation unit and a depth event trigger controller, wherein the input of the feedforward controller is the underwater glider's diving motion expectation or the upward motion expectation, and the motion expectation is the speed V s and glide inclination ξ s When the underwater glider receives a diving command, the input of the feedforward controller is the desired diving motion. When the underwater glider receives a floating command, the input of the feedforward controller is the desired floating motion. The output of the feedforward controller is the desired oil bag additional mass m of the underwater glider. bs and the desired pitch steering amount r of the underwater glider p1s ; The input of the six-degree-of-freedom rigid body dynamics model is: the additional mass of the oil bag m bs , desired pitch rudder amount r p1s , the underwater glider state η at the current moment and the time interval Δt, the output of the six-degree-of-freedom rigid body dynamics model is: the increment of the translational linear velocity vector of the underwater glider within the time interval Δt and the increment of the rotational angular velocity vector The first calculation module calculates the increment of the translation linear velocity vector within the time interval Δt and the increment of the rotational angular velocity vector Integrate them respectively to obtain the translation linear velocity vector V(t+Δt) and the rotation angular velocity vector Ω(t+Δt), and update the underwater glider state η; The inputs of the six-degree-of-freedom rigid body kinematics model are: the underwater glider state η updated by the first calculation module, the ocean current velocity vector V at the current position at time t in the inertial coordinate system, f (μ1,t) and time interval Δt, the output of the six-degree-of-freedom rigid body kinematic model is: the increment of the current position of the underwater glider in the inertial coordinate system within the time interval Δt and the increment of the Euler angle of the underwater glider in the inertial coordinate system The second calculation module calculates the position increment within the time interval Δt and the increment of Euler angles Integrate them respectively to obtain the updated position μ1(t+Δt) and the updated Euler angle μ2(t+Δt), and update the underwater glider state η; The target heading angle ψ target The yaw angle in the updated Euler angle μ2(t+Δt) is used as the input of the heading angle compensation unit. The heading angle compensation unit adjusts the yaw angle of the underwater glider, and the output of the heading angle compensation unit is the adjustment amount of the roll rudder angle; The depth event triggers the controller to monitor the diving depth Z in the updated position μ1(t+Δt) of the underwater glider. When the diving depth Z is greater than or equal to the maximum diving depth Z of the underwater glider, the controller will automatically start to monitor the diving depth Z in the updated position μ1(t+Δt) of the underwater glider. max When the depth setting event triggers the controller to output the floating instruction, the floating instruction makes the input of the feedforward controller the floating movement expectation, thereby causing the underwater glider to float upward; when the underwater glider floats to the water surface, the profile movement is completed; The ocean flow field setting module constructs the ocean flow field; The digital twin module simulates the complete profile of the underwater glider based on the roll angle adjustment output by the heading angle compensation unit and the ascent command output by the depth-fixed event trigger controller, and obtains the profile motion trajectory. The visualization module constructs a two-dimensional interface and a three-dimensional interface, wherein the two-dimensional interface is used to display the coordinate position of the underwater glider in the two-dimensional map, and the three-dimensional interface is used to display the cross-sectional motion trajectory of the underwater glider in the three-dimensional map.

2. The underwater glider ocean collaborative visual simulation system according to claim 1, characterized in that: The state η is defined as: where μ1 = [X, Y, Z] T represents the position component of the underwater glider in the inertial coordinate system, represents the Euler angle of the underwater glider in the inertial coordinate system, V = [u, v, w] T is the velocity component of the underwater glider in the body coordinate system, Ω=[p,q,r] T represents the angular velocity component of the underwater glider in the body coordinate system.

3. The underwater glider ocean collaborative visual simulation system according to claim 2, characterized in that: The ocean flow field setting module uses data-driven modal method or function-built modal method to construct the ocean flow field.

4. The underwater glider ocean collaborative visual simulation system according to claim 2, characterized in that: The underwater glider ocean collaborative visual simulation system also includes: an ocean current action mechanism module, which calculates the ocean current force F of the underwater glider at the current position. f and moment M f ; Where, is the generalized inertia matrix of the underwater glider, the ocean current velocity v f (μ1,t) is the ocean current velocity at time t of the three-dimensional coordinates of the underwater glider’s current position in the body coordinate system, is the cross product operator.

5. The underwater glider ocean collaborative visual simulation system according to claim 2, characterized in that: The feedforward controller calculates the oil bag additional mass m through the following formula: bs and the desired pitch rudder r p1s : i s =ξ s -a s u s =V s cosα s w s =V s sinα Among them, α s is the steady-state angle of attack, θ s is the desired pitch angle, g is the acceleration due to gravity, K L0 ,K L ,K D0 ,K D ,K m is the viscous hydrodynamic coefficient, M f1 is the additional mass coefficient of the underwater glider along the b1 direction in the body coordinate system, M f3 is the additional mass coefficient of the underwater glider along the b3 direction in the body coordinate system, u s is the desired velocity component of the underwater glider in the b1 direction in the body coordinate system, w s is the expected velocity component of the underwater glider in the b3 direction in the body coordinate system, r h1 is the distance from the center of mass of the underwater glider to the center of buoyancy in the body coordinate system along the b1 direction, r h3 is the distance from the center of mass of the underwater glider to the center of buoyancy in the body coordinate system along the b3 direction, m p is the mass of the movable mass block inside the underwater glider, m h represents the mass of the underwater glider shell.

6. The underwater glider ocean collaborative visual simulation system according to claim 5, characterized in that: The differential equation of the six-degree-of-freedom rigid body dynamics model is: Where M is the generalized mass matrix of the underwater glider, P is the momentum of the underwater glider in the body coordinate system, Π is the angular momentum of the underwater glider in the body coordinate system, is the inverse velocity transfer matrix, r h =[r h1 ,r h2 ,r h3 ] T is the component of the distance from the center of mass to the center of buoyancy of the underwater glider shell in the body coordinate system, r b =[r b1 ,r b2 ,r b3 ] T is the distance from the center of mass of the underwater glider oil bag to the center of buoyancy, r p =[r p1 +r px ,R p sinγ,R p cosγ] T is the component of the distance from the center of mass to the center of buoyancy of the movable mass block of the underwater glider, r p1 is the actual pitch rudder amount, r px is the distance between the movable mass block and the buoyancy center along the fuselage direction, R p represents the eccentricity of the movable mass block, γ represents the rolling angle of the movable mass block, m b is the actual additional mass of the oil bag, F v and M v is the viscous hydrodynamic force and torque in the underwater glider body coordinate system, F f is the ocean current force acting on the underwater glider at the current position, which is calculated by the ocean current mechanism module; M f is the torque of the ocean current force on the underwater glider at the current position.

7. The underwater glider ocean collaborative visual simulation system according to claim 2, characterized in that: The differential equation of the six-degree-of-freedom rigid body kinematic model is: Where R eb is the velocity transfer matrix of the underwater glider, I eb is the attitude transfer matrix of the underwater glider, where the velocity transfer matrix R eb and attitude transfer matrix I eb Calculated based on the Euler angle μ2(t) of the underwater glider at time t, is the increment of the x-coordinate in the inertial coordinate system within the time interval Δt, is the increment of the y coordinate in the inertial coordinate system within the time interval Δt, is the increment of the z coordinate in the inertial coordinate system within the time interval Δt, is the increment of the rolling angle of the underwater glider in the inertial coordinate system, is the increment of the pitch angle of the underwater glider in the inertial coordinate system, is the increment of the yaw angle of the underwater glider in the inertial coordinate system.

8. The underwater glider ocean collaborative visual simulation system according to claim 7, characterized in that: The heading angle compensation unit uses deviation threshold triggering or accumulated time triggering to adjust the yaw angle of the underwater glider.

9. The underwater glider ocean collaborative visual simulation system according to claim 8, characterized in that: The deviation threshold is triggered when the yaw angle is equal to the target heading angle ψ target When the error between the two is greater than or equal to the deviation threshold, the heading angle compensation unit adjusts the yaw angle of the underwater glider; the cumulative time trigger is a time threshold at each interval, and the heading angle compensation unit adjusts the yaw angle of the underwater glider; the method for the heading angle compensation unit to adjust the yaw angle of the underwater glider is to adjust the roll rudder angle so that the yaw angle is consistent with the target heading angle ψ target The error approaches zero.

10. The underwater glider ocean collaborative visual simulation system according to claim 9, characterized in that: The digital twin module defines the mission area of ​​the underwater glider, sets the route, and calculates the yaw distance d in the ocean flow field constructed by the ocean flow field setting module. p , yaw distance d p As an evaluation index for underwater glider motion simulation.

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