A data matching method for real sea area-simulation scene-hull motion model

Abstract

The invention discloses a data matching method of a real sea area-simulation visual scene-hull motion model, and relates to the field of ship test technology. The method comprises: dividing the display area of ​​the visual simulation platform to form an inner field, a transition zone, and an outer field; determining the wave fields of the inner field area and the outer field area, and obtaining the relative position of the target ship and the inner field wave; inputting the relative position of the target ship and the inner field wave, the propeller and rudder information of the target ship, and the control signal into the hull motion mechanics model, and obtaining the ship motion response result, including various forces of the ship and the six-degree-of-freedom motion of the hull; matching the wave fields of the inner field area and the outer field area, so as to determine the wave field of the transition zone; and displaying the hull motion posture and the waves of the inner field, the transition zone, and the outer field in real time in the visual simulation platform according to the six-degree-of-freedom motion of the hull. The data matching ensures that the picture is continuous and smooth, and can more realistically depict the navigation process of the ship in a complex environment.

Description

Technical Field

[0001] The invention relates to the technical field of ship testing, in particular to a data matching method of a real sea area-simulated scene-hull motion model. Background Art

[0002] Semi-physical simulation connects physical equipment or real-time human manipulation to the simulation loop. Compared with virtual simulation technology, it is more realistic and more economical and efficient than traditional physical experiments. It has irreplaceable advantages in product development and performance testing, especially in the study of complex conflicting problems. This technology has been applied to the field of shipping and sea, and a navigation simulator has been developed, which is mostly used for crew training. The authenticity and accuracy of the existing platform cannot meet the research needs of ship navigation performance. The main problem is that too many simplifications are made in the process of representing the wave environment and solving the ship motion, which cannot accurately reflect the interaction between the ship, the environment, and the operator.

[0003] At present, the existing technology mainly uses the spectrum method to linearly superimpose multiple sine waves to achieve wave simulation, rather than using data-driven methods to present the visual scene. The depiction of the actual movement of the waves is distorted and cannot truly reflect the movement of three-dimensional waves. In addition, when calculating the forces on the ship, the real-time changes of the waves are not considered and empirical formulas are used. The obtained ship motion posture is not accurate enough and cannot reflect the changing characteristics of the waves. The relative motion of the ship and the waves shown in the picture is inconsistent, and the simulation results are not in line with reality. Therefore, the existing semi-physical simulation platform cannot truly depict the navigation process of a ship after human control in a complex environment. Summary of the invention

[0004] In response to the needs of ship navigation performance research and control strategy effect evaluation, as well as the current lack of effective methods to construct a real ocean environment and calculate accurate ship motion, the present invention proposes a data matching method of real sea area-simulated vision-hull motion model, which incorporates control signals and reflects physical data. It can be used to establish a simulation platform that considers the coupling effects of environment-ship-control factors in high sea conditions.

[0005] The technical solution of the present invention is as follows:

[0006] A data matching method of real sea area-simulated scene-hull motion model comprises the following steps:

[0007] The visual simulation platform display area is divided into an inner field, a transition area, and an outer field with the initial position of the target ship as the center and outward in sequence;

[0008] Determine the wave fields in the inner and outer areas, and obtain the relative position of the target ship and the inner field waves;

[0009] The relative position of the target ship and the infield waves, the propeller and rudder information of the target ship and the control signal are input into the hull motion mechanics model to obtain the ship motion response results, including various forces on the ship and the six-degree-of-freedom motion of the hull;

[0010] Match the wave fields of the inner field area and the outer field area to determine the wave field of the transition area;

[0011] The motion posture of the ship, as well as the waves in the inner field, transition area and outer field are displayed in real time on the visual simulation platform according to the six-degree-of-freedom motion of the ship.

[0012] A further technical solution is to form an inner field, a transition area and an outer field in sequence outward from the initial position of the target ship, including:

[0013] Select the target ship and set the initial position of the ship;

[0014] Taking the mid-longitudinal section of the ship as the symmetry plane, the area within a certain range around the hull is divided into the inner field, and its boundary is the distance y in front of the bow in the longitudinal direction. 1 times the length of the ship, y behind the stern 2 times the length of the ship, and the distance from the center line to the two sides in the horizontal direction is x 1 Captain times;

[0015] The same symmetry plane is used to expand outward from the inner field to construct the transition zone, whose boundaries are the two sides of the inner field boundary y in the longitudinal direction. 3 times the length of the ship, and the other two sides are x from the corresponding inner field boundaries in the horizontal direction. 2 Captain times;

[0016] Outside the transition zone, the remaining display area of ​​the visual simulation platform is defined as the outfield.

[0017] A further technical solution is to determine the wave field in the inner field area, including:

[0018] Obtain instantaneous wave surface data of the real sea area around the ship, remove abnormal measurement data through multi-level filtering, fit discrete 3D wave surface point cloud data and carry out inversion of the wave field in the real sea area, and conduct secondary development based on the visual simulation platform to form the measured wave spectrum function around the ship that is directly applied to visual simulation and mechanical model;

[0019] According to the set wave level, the internal field waves are generated based on the wave spectrum function measured around the ship.

[0020] A further technical solution is to determine the wave field in the inner field area, and also includes:

[0021] Characteristic parameters are extracted based on the measured wave-making interference field around the ship, and the wave-making field around the ship is superimposed on the original inner field wave field displayed on the visual simulation platform. The characteristic parameters include wave-making range, wave crest and trough spacing, and distribution angle.

[0022] A further technical solution is to determine the wave field in the outer field area, including:

[0023] Based on the ocean color, current direction, and wave height data obtained from real ocean satellite observations, mixed reality technology is used to restore the wave effects in the outdoor area on the visual simulation platform.

[0024] A further technical solution is to calculate the ship motion response results, including:

[0025] According to the control signal, the speed and rudder angle of the target ship change accordingly, and the wet surface area formed by the relative position of the target ship and the inner field waves is integrated to calculate the hull force, propeller force, rudder force, wave force, wind force, flow force and the forces of other ships on the target ship in the current working conditions. Then, the motion conditions of the ship in six degrees of freedom, namely surge, sway, bow pitch, roll, heave and pitch, are derived through the hull motion mechanics model.

[0026] A further technical solution is to match the wave fields of the inner field area and the outer field area to determine the wave field of the transition area, including:

[0027] The three-dimensional wave surface data of the internal and external fields are converted into two-dimensional grayscale images. According to the principle of dense to sparse, the grid is divided along the height direction with the water plane as the center. The grid nodes of the internal and external field boundaries at the water plane are matched by the SIFT algorithm, and the wave heights of the internal and external field boundaries are obtained.

[0028] Assume that according to the wave field generation method in the inner field area, n points are distributed in each wavelength direction in the transition area, and the distance between the i-th point and the inner field boundary is d i , the corresponding wave height is h i ;

[0029] Assume that according to the wave field generation method in the external field area, m points are distributed in each wavelength direction in the transition area, and the distribution positions of the n points do not overlap. The distance between the jth point among the m points and the external field boundary is d j , the corresponding wave height is h j ;

[0030] According to the distance weighted interpolation concept, the wave height H at the actual node in each wavelength in the transition zone is calculated in turn using the following formula:

[0031]

[0032] A further technical solution is that, in order to ensure that the number of nodes in each wavelength direction in the transition zone is sufficient, the values ​​of m and n are not less than 2 to the seventh power.

[0033] Its further technical solution is that the method further comprises:

[0034] When the inner field waves are displayed in real time on the visual simulation platform, the waveform distribution around the ship in the inner field is adjusted according to the six-degree-of-freedom motion of the hull and the control signal, and the relative position of the target ship and the inner field waves is updated in real time, and the ship motion response results are recalculated.

[0035] The beneficial technical effects of the present invention are:

[0036] (1) The display range of the visual simulation platform is divided into different areas. In the inner field area where higher accuracy and authenticity are required, the wave surface data measured in the actual sea area is used to replace the traditional theoretical two-dimensional long-peak wave spectrum, and the hull motion mechanics model is input to carry out calculations. In the outer field area where hull motion calculations are not involved, real satellite meteorological data is used to restore the ocean effect through mixed reality technology, and wave phase matching is achieved through the transition zone to improve efficiency and meet the maximum calculation time of the screen display.

[0037] (2) According to the motion posture of the hull and the control signal, the relative position of the target ship and the internal field waves is judged in real time, and the wave force acting on the ship is calculated using the time domain method. Compared with the frequency domain method or empirical formula used in mainstream technologies, this method can better reflect the interaction between the ship, the environment and the operator while improving the calculation accuracy.

[0038] (3) The wave-making range, wave crest-trough spacing, distribution angle and other characteristic parameters are extracted from the measured wave-making interference field around the ship, which fully restores the wave surface distribution near the hull when the ship is moving. This is different from the existing technology that directly superimposes a simple ship wave-making effect on the scene. It is more realistic when reversing, turning, Z-shaped motion or random control. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a flow chart of the data matching method of real sea area-simulated scene-hull motion model provided by this application.

[0040] Figure 2 This is the architecture diagram of the semi-physical simulation platform for ship maneuvering motion in waves provided by this application. DETAILED DESCRIPTION

[0041] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0042] Combination Figure 1 , Figure 2The present application provides a data matching method of real sea area-simulated scene-hull motion model, which specifically includes the following steps:

[0043] Step 1: Divide the display area of ​​the visual simulation platform, and form the inner field, transition area, and outer field outward in sequence with the initial position of the target ship as the center.

[0044] Select the target ship and set the initial position of the ship to form a simulation platform visual display pattern of inner field, transition area and outer field, which expands from the inside to the outside. Specifically, take the longitudinal section of the ship as the symmetry plane, divide the area within a certain range around the hull into the inner field, and its boundary is the distance y in front of the bow in the longitudinal direction. 1 times the length of the ship, y behind the stern 2 times the length of the ship, and the distance from the center line to the two sides in the horizontal direction is x 1 times the length of the ship; use the same symmetry plane to expand outward from the inner field as the center to construct a transition zone, whose boundaries are the two sides of the corresponding inner field boundary y in the longitudinal direction. 3 times the length of the ship, and the other two sides are x in the horizontal direction from the corresponding inner field boundary 2 times the length of the ship; outside the transition area, the remaining display area of ​​the visual simulation platform is defined as the outfield.

[0045] In this embodiment, the target ship is selected as an ONR (office of naval research) inboard ship, whose vertical length (i.e., ship length) is 154m. According to the set initial position of the ship, the intersection of the ship's centerline plane, the mid-station plane, and the base plane is taken as the coordinate origin to construct the ship's rectangular coordinate system O-xyz. The x-axis is the intersection of the mid-station plane and the base plane, with the direction pointing to the starboard side as positive (transverse), the y-axis is the intersection of the centerline plane and the base plane, with the direction pointing to the bow as positive (longitudinal), and the z-axis is positive downward. Let y be the intersection of the centerline plane and the base plane. 1 =x 1 =1,y 2 =1.5,y 3 =3,x 2 =2. With the origin as the center, an inner field area with a length of 539m in the longitudinal direction and a width of 308m in the transverse direction is divided, and its boundary is 154m in front of the bow and 231m behind the bow in the longitudinal direction; with the inner field as the center, it expands outward to construct a transition area of ​​924m×616m (longitudinal×lateral); the display range of the simulation platform can be changed according to the perspective selected by the operator, and the area outside the transition area is uniformly defined as the outer field.

[0046] Step 2: Determine the wave field in the inner field area and obtain the relative position of the target ship and the inner field waves.

[0047] Wave radar, binocular recognition and other technologies are used to obtain instantaneous wave surface data in the real sea area around the hull. After multi-level filtering to eliminate abnormal measurement data, discrete three-dimensional wave surface point cloud data is fitted and the wave field in the real sea area is inverted. Secondary development is carried out based on the visual simulation platform to form a spectrum function of the measured wave around the ship that can be directly applied to the visual simulation and mechanical model. According to the set wave level, the inner field wave is generated based on the spectrum function of the measured wave around the ship, and the wave data is transmitted to the semi-physical simulation platform. The real sea area waves are displayed in the inner field area determined in step 1. At the same time, characteristic parameters are extracted according to the measured wave interference field around the ship, and the wave field around the ship is superimposed on the original inner field wave field displayed on the visual simulation platform. After obtaining the inner field waves, the characteristic unit is used to complete the discretization near the waterline of the hull. By matching the wave surface shape with the physical surface conditions of the waterline, the relative position of the target ship and the inner field wave can be determined in combination with the current hull motion posture.

[0048] In this embodiment, according to the wave-making field around the ship at different speeds and different drift angles in still water, characteristic parameters such as wave-making range, distance between wave crests and troughs, and distribution angle are extracted, and a wave-making characterization model around the ship is established to reflect the actual wave-making field around the ship under different working conditions.

[0049] Step 3: Input the relative position of the target ship and the infield waves, the propeller and rudder information of the target ship, and the control signal into the hull motion mechanics model to obtain the ship motion response result.

[0050] Input the propeller and rudder information of the target ship, monitor the control signals including the engine clock signal and the wheel and rudder signal in real time, receive the operator's instructions through the human-machine interface technology, and transmit them through high-throughput communication technology, and use the dynamic link database generated by the hull motion mechanics model to calculate the various forces on the ship at the current moment, including hull force, propeller force, rudder force, wave force, etc. In this embodiment, in addition to the propeller and rudder size information, the ship's maneuverability hydrodynamic derivative, drag coefficient, roll damping coefficient, propeller and rudder installation method, propeller and rudder interference coefficient, etc. are stored in the database together. After the target ship is determined, the simulation platform calls the relevant data to input the mechanical model, which is used to calculate the forces on the ship in the current working condition. After receiving the changed car clock signal and wheel and rudder signal, the speed and rudder angle of the target ship change accordingly. The wet surface area formed by the relative position of the target ship and the infield waves is integrated to calculate the hull force, propeller force, rudder force, wave force, wind force, flow force and other forces on the target ship in the current working condition, fully characterizing the influence of waves on the hull motion, and then deriving the ship's six degrees of freedom motion of sway, sway, bow pitch, roll, heave and pitch through the hull motion mechanical model.

[0051] The hull motion mechanics model selected in this embodiment is implemented based on an existing mechanics model and will not be described in detail here.

[0052] Step 4: Use the network communication protocol to transmit the calculated ship motion response results to the visual simulation platform, use data compensation technology to ensure smooth display effect, and feed back the ship motion to the ship-surrounding wave characterization model. When the inner field waves are displayed in real time on the visual simulation platform, the waveform distribution around the ship in the inner field is adjusted according to the six-degree-of-freedom motion of the hull and the control signal, and the relative position of the target ship and the inner field waves is updated in real time. The ship motion response results are recalculated according to the method in step 3.

[0053] Step 5: Determine the wave field in the outer field area.

[0054] While step 2 is being carried out, based on the ocean water color, current direction, and wave height data obtained from real ocean satellite observations, mixed reality technology is used to restore the wave effects in the external field area in the visual simulation platform. The artificially selected weather conditions such as sunny, rainy, foggy, and snowy weather are transmitted to the visual simulation platform through the network communication protocol as environmental parameters, forming wave field information in a larger range in the visual simulation.

[0055] Step 6: Match the wave fields of the inner and outer areas to determine the wave field of the transition area.

[0056] In order to improve the matching speed, the three-dimensional wave surface data of the internal and external fields are converted into a two-dimensional grayscale image. According to the principle of dense to sparse, the grid is divided along the height direction with the interface between water and air (i.e., the waterline plane) as the center. The grid nodes of the internal and external field boundaries at the waterline plane are matched by the SIFT (Scale Invariant Feature Transform) algorithm, and the wave height of the internal and external field boundaries is obtained. Assume that according to the wave field generation method of the internal field area in step 2, n points are distributed in each wavelength direction in the transition zone, and the distance between the i-th point and the internal field boundary is d i , the corresponding wave height is h i Assume that according to the wave field generation method in the external field area in step 5, m points are distributed in each wavelength direction in the transition area, and the distribution positions of the n points do not overlap. The distance between the jth point among the m points and the external field boundary is d j , the corresponding wave height is h j ,h i and h j It can be understood as the virtual value corresponding to different positions in the transition zone. According to the distance weighted interpolation idea, the wave height H at the actual node in each wavelength in the transition zone is calculated in turn using the following formula:

[0057]

[0058] It should be noted that in order to ensure that the number of nodes in each wavelength direction in the transition zone is sufficient, it is recommended that the values ​​of m and n be no less than 2 to the power of 7, and the values ​​should also be changed according to 2. n Increase.

[0059] Step 7: Based on the 6-DOF motion of the ship, the motion posture of the ship and the waves in the inner field, transition area and outer field are displayed in real time on the visual simulation platform.

[0060] Step 8: Repeat steps 2 to 7, and store the calculated data and received signals in real time to the data server for subsequent analysis of the ship's maneuverability in waves until the operator ends the simulation test.

[0061] In this embodiment, the calculated data include the real-time calculation results of the acceleration of six degrees of freedom, namely the longitudinal acceleration, lateral acceleration, vertical acceleration, roll acceleration, pitch acceleration, and bow acceleration; the real-time calculation results of the speed of six degrees of freedom, namely the longitudinal speed, lateral speed, vertical speed, roll speed, pitch speed, and bow speed; as well as the lateral position, longitudinal position, vertical position, heading angle, roll angle, and pitch angle.

[0062] The data matching method of the above-mentioned real sea area-simulated vision-hull motion model provided in the present application takes into account both calculation accuracy and picture authenticity, forming a simulation platform vision display pattern of inner field-transition zone-outer field trinity, which expands layer by layer from the inside to the outside. The inner field is based on wave data measured in the real sea area, and the outer field uses mixed reality technology to restore the real wave effect according to satellite meteorological data. Wave phase matching is performed in the transition zone to ensure the continuity and smoothness of the picture. At the same time, the control signal of the operator is received in real time. Considering the interaction between ship-environment-operator, the real sea area measured data together with the control signal are input into the hull motion mechanics model for calculation. Compared with the existing semi-physical simulation technology, it more realistically portrays the navigation process of the ship in a complex environment.

[0063] The above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A data matching method of real sea area-simulated scene-hull motion model, characterized in that: include: The visual simulation platform display area is divided into an inner field, a transition area, and an outer field with the initial position of the target ship as the center and outward in sequence; Determine the wave fields in the inner and outer areas, and obtain the relative position of the target ship and the inner field waves; The relative position of the target ship and the infield waves, the propeller and rudder information of the target ship and the control signal are input into the hull motion mechanics model to obtain the ship motion response result, including various forces on the ship and the six-degree-of-freedom motion of the hull; Matching the wave fields of the inner field area and the outer field area to determine the wave field of the transition area; According to the six-degree-of-freedom motion of the hull, the motion posture of the hull and the waves in the inner field, transition area and outer field are displayed in real time on the visual simulation platform; Among them, determining the wave field in the inner field area and obtaining the relative position of the target ship and the inner field waves include: obtaining instantaneous wave surface data of the real sea area around the hull, removing abnormal measurement data through multi-level filtering, fitting discrete three-dimensional wave surface point cloud data and performing inversion of the wave field in the real sea area, and performing secondary development based on the visual simulation platform to form a spectrum function of the measured waves around the ship that is directly applied to the visual simulation and mechanical model; According to the set wave level, generating the inner field waves based on the wave spectrum function measured around the ship; After obtaining the inner field waves, the characteristic unit is used to complete discretization near the hull water plane, and the relative position of the target ship and the inner field waves is determined by matching the wave surface shape with the physical surface condition of the water plane and combining the current hull motion posture; Among them, the calculation results of ship motion response include: According to the control signal, the speed and rudder angle of the target ship are changed accordingly, and the wet surface area formed by the relative position of the target ship and the inner field waves is integrated to calculate the hull force, oar force, rudder force, wave force, wind force, flow force and the force of other ships on the target ship in the current working condition, and then the motion conditions of the six degrees of freedom of the ship, namely, surge, sway, pitch, roll, heave and pitch, are derived through the hull motion mechanics model; The step of matching the wave fields of the inner field area and the outer field area to determine the wave field of the transition area includes: The three-dimensional wave surface data of the internal and external fields are converted into two-dimensional grayscale images. According to the principle of dense to sparse, the grid is divided along the height direction with the water plane as the center. The grid nodes of the internal and external field boundaries at the water plane are matched by the SIFT algorithm, and the wave heights of the internal and external field boundaries are obtained. Assuming that the wave field is generated in the inner field area, the distribution in each wavelength direction in the transition zone is n Points, remember n Point i The distance between the point and the inner field boundary is d i , the corresponding wave height is h i ; Assume that according to the wave field generation method in the external field area, the distribution in each wavelength direction in the transition zone is m points, and n The distribution positions of the points do not overlap, so m Point j The distance between the point and the outer field boundary is d j , the corresponding wave height is h j ; According to the distance weighted interpolation concept, the wave height at the actual node in each wavelength in the transition zone is calculated in turn using the following formula: H : 。 2. The data matching method of real sea area-simulated scene-hull motion model according to claim 1 is characterized in that: The inner field, transition area and outer field are formed outward in sequence with the initial position of the target ship as the center, including: Select the target ship and set the initial position of the ship; Taking the mid-longitudinal section of the ship as the symmetry plane, the area within a certain range around the hull is divided into the inner field, whose boundaries are y1 times the ship length in front of the bow in the longitudinal direction, y2 times the ship length in the rear of the stern, and x1 times the ship length in the transverse direction on both sides; Use the same symmetry plane to expand outward from the inner field as the center to construct a transition zone, whose boundaries are y3 times the ship length from the corresponding inner field boundary on both sides in the longitudinal direction, and x2 times the ship length from the corresponding inner field boundary on the other two sides in the transverse direction; Outside the transition area, the remaining display area of ​​the visual simulation platform is defined as an outfield.

3. The data matching method of real sea area-simulated scene-hull motion model according to claim 1 is characterized in that: Determine the wave field in the inner field area, including: Characteristic parameters are extracted according to the measured wave-making interference field around the ship, and the wave-making field around the ship is superimposed on the original inner field wave field displayed on the visual simulation platform. The characteristic parameters include wave-making range, wave crest and trough spacing, and distribution angle.

4. The data matching method of real sea area-simulated scene-hull motion model according to claim 1 is characterized in that: Determine the wave field in the outfield area, including: Based on the ocean water color, current direction, and wave height data obtained from real ocean satellite observations, mixed reality technology is used to restore the wave effects in the outdoor area in the visual simulation platform.

5. The data matching method of real sea area-simulated scene-hull motion model according to claim 1 is characterized in that: To ensure that there are enough nodes in each wavelength direction in the transition zone, m and n The value of is not less than 2 to the power of 7.

6. The data matching method of real sea area-simulated scene-hull motion model according to any one of claims 1 to 5, characterized in that: The method further comprises: When the inner field waves are displayed in real time in the visual simulation platform, the waveform distribution around the ship in the inner field is adjusted according to the six-degree-of-freedom motion of the hull and the control signal, and the relative position of the target ship and the inner field waves is updated in real time, and the ship motion response result is recalculated.

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