A method and system for automatic hovering of a vessel

Abstract

The present invention discloses a method for automatic hovering of a vessel, including: obtaining the yaw axis angle information of the vessel, obtaining a distance parameter according to the vessel's GPS position information and the position information of the hovering target point, and correcting the error of the obtained yaw axis angle information according to the vessel's GPS position information to obtain a yaw axis angle parameter; calculating a steering throttle control parameter according to the yaw axis angle parameter, and calculating a forward throttle control parameter according to the distance parameter; controlling the steering of the vessel according to the steering throttle control parameter so that the bow of the vessel is directly facing the hovering target point, and controlling the output of the forward throttle of the vessel according to the forward throttle control parameter to approach the hovering target point; performing a hovering operation after approaching the hovering target point, and maintaining the steering throttle control parameter and the forward throttle control parameter at that moment. At the same time, a system for automatic hovering of a vessel is also disclosed.

Description

Technical Field

[0001] The present invention relates to the field of artificial intelligence technology, and particularly to a method and system for automatically hovering a ship. Background Art

[0002] With the wave of artificial intelligence and the rise of unmanned driving technology, unmanned ship technology has emerged as the times require. During the field application of unmanned ship technology, the ship can normally execute tasks. However, after a task is completed and before the next instruction is sent, it is difficult for the ship to achieve the state of "standing by in place". That is, as a floating object, without applying throttle power, the hull is easily displaced by the action of water flow. This forced displacement usually makes the ship get closer to complex scenarios such as bridge holes, bridge piers or shore bushes. Such a complex external environment brings great uncertainty and inoperability to the subsequent control of the unmanned ship, and there are also relatively large potential safety hazards. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method and system for automatically hovering a ship, so as to achieve the purpose of automatically hovering at a fixed point position.

[0004] According to one aspect of the present invention, there is provided a method for automatically hovering a ship, which includes:

[0005] Obtain the yaw axis angle information of the ship, obtain a distance parameter according to the ship's gps position information and the position information of the hovering target point, and correct the obtained yaw axis angle information according to the ship's gps position information to obtain a yaw axis angle parameter;

[0006] Calculate a steering throttle control parameter according to the yaw axis angle parameter, and calculate a forward throttle control parameter according to the distance parameter;

[0007] Control the steering of the ship according to the steering throttle control parameter so that the bow of the ship is directly facing the hovering target point, and control the output of the forward throttle of the ship according to the forward throttle control parameter to approach the hovering target point;

[0008] After approaching the hovering target point, perform a hovering operation, and maintain the steering throttle control parameter and the forward throttle control parameter at that moment.

[0009] A further technical solution thereof is: the calculating a steering throttle control parameter according to the yaw axis angle parameter includes:

[0010] Calculate an angle deviation value between the yaw axis angle parameter and the target angle of the hovering target point;

[0011] Calculate a steering throttle control parameter according to the angle deviation value to control the steering of the ship so that its bow is directly facing the hovering target point.

[0012] Its further technical solution is: The steering throttle control parameter calculated according to the angle deviation value includes:

[0013] Calculating the lateral change linear velocity V of the hull according to the formula where T is a preset vessel control period, y is the actual displacement of the hull, Δyaw is the angle deviation value, G is the maximum steering angular velocity of the hull, N is the number of control periods for achieving angle correction, and deg is the true yaw axis angle value that should be corrected by the control in each control period on average;

[0014] Obtaining the corresponding steering throttle control parameter from the hull dynamics or throttle reference table according to the lateral change linear velocity V of the hull.

[0015] Its further technical solution is: The steering throttle control parameter calculated according to the angle deviation value includes:

[0016] Calculating the target angular velocity W according to the formula where T is a preset vessel control period, y is the actual displacement of the hull, Δyaw is the angle deviation value, G is the maximum steering angular velocity of the hull, N is the number of control periods for achieving angle correction, and deg is the true yaw axis angle value that should be corrected by the control in each control period on average;

[0017] Obtaining the corresponding steering throttle control parameter from the hull dynamics or throttle reference table according to the target angular velocity W.

[0018] Its further technical solution is: The forward throttle control parameter calculated according to the distance parameter includes:

[0019] Judging whether the distance parameter is less than or equal to a first preset distance, where the first preset distance is the natural sliding distance of the vessel at the maximum speed;

[0020] If so, calculating the target speed v according to the formula where f is the resultant resistance of the hull, m is the mass of the hull, and d is the remaining distance from the vessel to the hovering target point;

[0021] Obtaining the forward throttle control parameter according to the difference between the target speed v and the maximum speed of the vessel.

[0022] Its further technical solution is: The judging whether the distance parameter is less than or equal to the first preset distance further includes:

[0023] If not, the vessel travels at full throttle.

[0024] Its further technical solution is: After performing the hovering operation after approaching the hovering target point, it further includes:

[0025] Judge whether the ship is in a hovering stable state according to the distance parameter and the yaw-axis angle parameter within the preset time t. If so, maintain the steering throttle control parameter and the forward throttle control parameter at this moment.

[0026] Its further technical solution is: The judgment of whether the ship is in a hovering stable state according to the distance parameter and the yaw-axis angle parameter within the preset time t includes:

[0027] Sample and record the distance parameter within the preset time t and form an array

[0028] ; ;

[0029] Sample and record the yaw-axis angle parameter within the preset time t and form an array ;

[0030] Judge whether the maximum value of the distance parameter in the array L is less than or equal to the third preset distance, and at the same time calculate the variance of the data J, and judge whether the variance is less than the preset threshold;

[0031] If the maximum value of the distance parameter in the array L is less than or equal to the third preset distance and the variance is less than the preset threshold, the ship is in a hovering stable state.

[0032] Its further technical solution is: After judging whether the ship is in a hovering stable state according to the distance parameter and the yaw-axis angle parameter within the preset time t, it further includes: If not, re-execute the steps of obtaining the yaw-axis angle information of the ship, obtaining the distance parameter according to the ship's gps position information and the position information of the hovering target point, and performing error correction on the obtained yaw-axis angle information according to the ship's gps position information to obtain the yaw-axis angle parameter.

[0033] According to another aspect of the present invention, there is provided a ship automatic hovering system, which includes:

[0034] An acquisition unit for acquiring the yaw-axis angle information of the ship and obtaining the distance parameter according to the ship's gps position information and the position information of the hovering target point;

[0035] An error correction unit for performing error correction on the obtained yaw-axis angle information according to the ship's gps position information to obtain the yaw-axis angle parameter;

[0036] A calculation unit for calculating the steering throttle control parameter according to the yaw-axis angle parameter and calculating the forward throttle control parameter according to the distance parameter;

[0037] A control adjustment unit is used to control the steering of the vessel according to the steering throttle control parameter so that the bow of the vessel hovers directly above the target point, and then control the output of the forward throttle of the vessel according to the forward throttle control parameter to approach the hovering target point;

[0038] A hovering maintenance unit is used to perform a hovering operation after approaching the hovering target point and maintain the steering throttle control parameter and the forward throttle control parameter at that moment.

[0039] Compared with the prior art, the present invention obtains the yaw axis angle information of the vessel and the distance parameter between the vessel and the hovering target point, and corrects the error of the yaw axis angle information to obtain the yaw axis angle parameter, so as to calculate and obtain the steering throttle control parameter and the forward throttle control parameter respectively according to the yaw axis angle parameter and the distance parameter. Thus, the steering of the vessel is controlled according to the steering throttle control parameter so that the bow of the vessel hovers directly above the target point, that is, the orientation of the bow of the vessel is consistent with the direction of the hovering target point, and the output of the forward throttle of the vessel is controlled according to the forward throttle control parameter to approach the hovering target point and hover at the approaching hovering target point. It can be seen that the present invention realizes the purpose of automatically hovering at a fixed position by adjusting the orientation of the bow of the vessel and the output of the forward throttle, thereby avoiding the great uncertainty and inoperability brought by the movement of the vessel to a complex external environment due to the action of water flow to the subsequent vessel control, and at the same time reducing potential safety hazards. Description of the Drawings

[0040] Figure 1 It is a schematic flowchart of the vessel automatic hovering method provided by an embodiment of the present invention.

[0041] Figure 2 It is a schematic block diagram of the vessel automatic hovering system provided by an embodiment of the present invention. Detailed Embodiment

[0042] To make those of ordinary skill in the art understand the purpose, technical solution and advantages of the present invention more clearly, the following further elaborates the present invention with reference to the drawings and embodiments.

[0043] Refer to Figure 1 , Figure 1 It is a schematic flowchart of the vessel automatic hovering method provided by an embodiment of the present invention. As shown in the figure, the method includes the following steps S110 - S150:

[0044] S110. Obtain the yaw axis angle information of the vessel, obtain the distance parameter according to the vessel gps position information and the position information of the hovering target point, and correct the error of the obtained yaw axis angle information according to the vessel gps position information to obtain the yaw axis angle parameter.

[0045] In the present invention, a ship can be equipped with multiple sensors such as an inertial measurement sensor, a GPS positioning system, and a radar to obtain external environment information as well as its own position and attitude.

[0046] Specifically, in this embodiment, the yaw-axis angle information of the ship can be obtained in real time through the inertial measurement sensor carried by the ship, and error correction can be performed according to the GPS position information of the ship to obtain the yaw-axis angle parameter. This yaw-axis angle parameter is used to control the steering of the ship's bow so that the orientation of the ship's bow is consistent with the direction of the hovering target point; and the position information of the hovering target point can be the longitude and latitude coordinates of the hovering target point. In this step, the GPS position information of the ship and the longitude and latitude coordinates of the hovering target point can be converted from the geodetic coordinate system to the plane rectangular coordinate system, so as to calculate and obtain the distance parameter.

[0047] S120. Calculate the steering throttle control parameter according to the yaw-axis angle parameter, and calculate the forward throttle control parameter according to the distance parameter.

[0048] In the present invention, the ship can also collect the lateral throttle and the corresponding angular velocity as well as the longitudinal throttle and the corresponding speed through sensors, and the matching relationship between the lateral throttle and the angular velocity and between the longitudinal throttle and the speed can be stored in the hull dynamics or the throttle reference table.

[0049] In this step, the steering throttle control parameter is used to control the steering of the ship, and the forward throttle control parameter is used to control the forward speed of the ship.

[0050] Specifically, in this embodiment, calculating the steering throttle control parameter according to the yaw-axis angle parameter includes: calculating the angle deviation value between the yaw-axis angle parameter and the target angle of the hovering target point; calculating the steering throttle control parameter according to the angle deviation value to control the steering of the ship so that its bow is directly facing the hovering target point.

[0051] In some embodiments, if the lateral control is linear velocity control, calculating the steering throttle control parameter according to the angle deviation value specifically includes: according to the formula Calculate the lateral change linear velocity V of the hull; where T is a preset vessel control period, y is the actual displacement of the hull during travel, Δyaw is the angle deviation value, G is the maximum turning angular velocity of the hull, N is the number of control periods for achieving angle correction, and deg is the true yaw axis angle value that should be corrected by the control in each average control period; obtain the corresponding steering throttle control parameter from the hull dynamics or throttle reference table according to the lateral change linear velocity V of the hull. Understandably, during the process of the vessel from the current position to the hovering target point, with a control period T of 0.1 second, the change angle is Δyaw, and it is necessary to control the hull to zero the included angle between the bow direction and the hovering target point within N = [Δyaw / G] + 1 control periods, and deg is the angle change amount that needs to be achieved in each average control period T. is the lateral change displacement corresponding to each control period T; and the corresponding relationship between the lateral change linear velocity and the steering throttle control parameter is stored in the hull dynamics or throttle reference table, and the corresponding steering throttle control parameter can be obtained according to the calculated lateral change linear velocity V of the hull.

[0052] In this embodiment, during the task, continuously and real-time monitor the vessel's gps position information, denoted as point P, denote the hovering target point position information as point O, convert the coordinates of point P and point O from the geodetic coordinate system to the plane rectangular coordinate system, and then calculate the direction of the vector pointing from the current point P to the target point O, the angle of which is the target angle of the hovering target point, and the angle deviation value is the difference between this target angle and the current yaw angle of the vessel, that is, the included angle between the bow direction and the hovering target point.

[0053] In some embodiments, if the lateral control is angular velocity control, the calculating the steering throttle control parameter according to the angle deviation value may further include: according to the formula calculate the target angular velocity W; where T is a preset vessel control period, y is the actual displacement of the hull during travel, Δyaw is the angle deviation value, G is the maximum turning angular velocity of the hull, N is the number of control periods for achieving angle correction, and deg is the true yaw axis angle value that should be corrected by the control in each average control period; obtain the corresponding steering throttle control parameter from the hull dynamics or throttle reference table according to the target angular velocity W.

[0054] In some embodiments, the calculating the forward throttle control parameter according to the distance parameter includes: judging whether the distance parameter is less than or equal to a first preset distance, where the first preset distance is the natural sliding distance of the vessel at the maximum speed; if so, according to the formula calculate the target speed v; where f is the resultant resistance of the hull, m is the mass of the hull, and d is the remaining distance from the vessel to the hovering target point; obtain the forward throttle control parameter according to the difference between the target speed v and the maximum speed of the vessel; if not, the vessel travels at full throttle.

[0055] Understandably, a vessel running at full throttle means running at its maximum speed as the target speed. During the entire forward movement, the vessel's movement can be divided into a starting acceleration stage and a tail-point deceleration stage. According to the kinematic data of the hull itself, during the deceleration stage, the vessel can continue to slide for a certain distance due to inertia. The main resistances acting on the hull are viscous resistance and pressure drag. Among them, the magnitude of the viscous resistance is proportional to the movement speed, and the magnitude of the pressure drag is proportional to the square of the movement speed. When the speed is known, the natural sliding distance can be calculated. In the present invention, the forward throttle control adopts a real-time speed control mode with a control period of T. In each period, the speed speed and the yaw-axis angle information need to be obtained, and the remaining distance d from the vessel to the hovering target point and the natural sliding distance D2 at the current speed speed are calculated. Then, during the actual hovering process, t0 is recorded as the initial moment of the task, and tk is the moment of the kth control period, that is, tk - t0 = k * T. The moment tk is recorded as the moment when D2 > d is first satisfied. That is, from here on, the throttle is cleared, and the vessel naturally slides relying on the inertia of the hull and can pass through the target point. The distance error is |D2 - d|. Here, the corresponding estimated speed v can also be inversely solved depending on the remaining distance d, that is, the natural sliding distance of the vessel speed v is d. In order to minimize the distance error, it is necessary to control the estimated speed v of the vessel to be consistent with the actual speed speed. Then, in the next control period, the throttle value should be the throttle compensation value of the speed error between v and speed, rather than an absolute zero value. And then, in each subsequent control period, the speed error is continuously calculated and converted into a throttle compensation value to be passed to the next control period for execution.

[0056] S130. Control the steering of the vessel according to the steering throttle control parameters so that the bow of the vessel faces the hovering target point directly, and control the output of the forward throttle of the vessel according to the forward throttle control parameters to approach the hovering target point.

[0057] In the present invention, the farther the vessel is from the hovering target point, the greater the forward throttle needs to be applied. The forward throttle control parameters mainly control the vessel to approach near the hovering target point. And when the vessel is closer to the hovering target point, the forward throttle required to be applied is smaller. This throttle is only to offset the influence of the water flow and has a certain saturation limit. And when the bow orientation is not consistent with the direction of the hovering target point, the primary goal is direction adjustment. To avoid large errors, it is necessary to strictly control the forward speed, that is, the greater the angular difference between the bow and the direction of the hovering target point, the smaller the forward throttle to be applied, that is, the smaller the forward throttle control parameters. And when the bow orientation is consistent with the direction of the hovering target point, the primary goal is to reach the position, and the forward throttle control parameters can be larger. Based on the above principles, the present invention applies throttle to the thruster to gradually approach the target point, and the throttle size is positively correlated with the distance from the hovering target point.

[0058] S140. After approaching the hovering target point, perform a hovering operation and maintain the steering throttle control parameter and the forward throttle control parameter at that moment.

[0059] In this step, after hovering, the bow of the ship faces parallel to the water flow. For the ship, when the water flow does not change, only by maintaining the magnitude of the throttle value applied at the current moment can the position and direction be continuously maintained unchanged.

[0060] S150. Determine whether the ship is in a stable hovering state according to the distance parameter and the yaw axis angle parameter within the preset time t. If so, maintain the steering throttle control parameter and the forward throttle control parameter at this moment.

[0061] Specifically, the determination of whether the ship is in a stable hovering state according to the distance parameter and the yaw axis angle parameter within the preset time t includes: sampling and recording the distance parameter within the preset time t and forming an array ; sampling and recording the yaw axis angle parameter within the preset time t and forming an array ; determining whether the maximum value of the distance parameter in the array L is less than or equal to the third preset distance, and at the same time calculating the variance of the data J and determining whether the variance is less than the preset threshold; if the maximum value of the distance parameter in the array L is less than or equal to the third preset distance and the variance is less than the preset threshold, the ship is in a stable hovering state.

[0062] In this step, the preset threshold is preferably 1, the third preset distance is preferably 0.2 m, and the preset time t can be 30 s. Then, sampling is performed in each control cycle within 30 s to sample and record the ship's gps position information within 30 s. Combining with the position information of the hovering target point, calculate the distance parameter between the ship's gps position information and the position information of the hovering target point in the plane coordinate system , forming an array L. Similarly, sample and record the yaw axis angle parameter of the ship within 30 s and form an array J; then in this embodiment, if the variance is less than 1 and the maximum distance in the array L is less than or equal to 0.2 m, it means that the ship is relatively close to the hovering target point and the ship's angle does not change significantly in a short time, and it is regarded that the ship reaches a stable state. In this state, the ship faces parallel to the water flow. By maintaining the magnitude of the throttle value applied at the current moment, the position and direction can be continuously maintained unchanged. At this time, the water flow direction and the magnitude of the acting value can be output.

[0063] Understandably, in the present invention, if the water flow changes or other external factors cause the vessel to move away from the hovering target point by more than 2 meters or the angle of the vessel changes, steps S110 - S150 are repeated to hover again; and when the task end instruction is received, the automatic hovering task ends and waits for the instruction to execute the next task. It can be seen that the automatic hovering system of the vessel in the present invention can achieve the hovering function in a task-free state or with a fixed hovering target point, avoiding the uncertainty and inoperability of controlling the unmanned vessel caused by displacement close to complex scenarios such as bridge openings, bridge piers, or riverside bushes due to the action of water flow, which is conducive to quickly responding and executing the next task.

[0064] Refer to Figure 2 , Figure 2 which is a schematic block diagram of the automatic hovering system 10 of the vessel of the present invention. In the embodiment shown in the accompanying drawings, the automatic hovering system 10 of the vessel includes an acquisition unit 101, an error correction unit 105, a calculation unit 102, a control adjustment unit 103, and a hovering maintenance unit 104. Among them, the acquisition unit 101 is used to acquire the yaw axis angle information of the vessel and obtain a distance parameter according to the vessel's gps position information and the position information of the hovering target point; the error correction unit 105 is used to correct the acquired yaw axis angle information according to the vessel's gps position information to obtain a yaw axis angle parameter; in this embodiment, the yaw axis angle information of the vessel can be obtained in real time through an inertial measurement sensor carried by the vessel, and the error is corrected according to the vessel's gps position information to obtain a yaw axis angle parameter, which is used to control the steering of the vessel's bow so that the orientation of the vessel's bow is consistent with the direction of the hovering target point; and the position information of the hovering target point can be the longitude and latitude coordinates of the hovering target point. The vessel's gps position information and the longitude and latitude coordinates of the hovering target point are converted from the geodetic coordinate system to the plane rectangular coordinate system, so that the distance parameter can be calculated. The calculation unit 102 is used to calculate a steering throttle control parameter according to the yaw axis angle parameter and calculate a forward throttle control parameter according to the distance parameter; the steering throttle control parameter is used to control the steering of the vessel, and the forward throttle control parameter is used to control the forward speed of the vessel. The control adjustment unit 103 is used to control the steering of the vessel according to the steering throttle control parameter so that the vessel's bow is directly facing the hovering target point, and then control the output of the forward throttle of the vessel according to the forward throttle control parameter to approach the hovering target point. The hovering maintenance unit 104 is used to perform a hovering operation after approaching the hovering target point and maintain the steering throttle control parameter and the forward throttle control parameter at that moment; in the present invention, after hovering, the orientation of the vessel's bow is parallel to the water flow. For the vessel, when the water flow does not change, only by maintaining the magnitude of the throttle value applied at the current moment, the position can be continuously maintained without moving and the direction remains unchanged.

[0065] In summary, the present invention controls the steering of a vessel according to the steering throttle control parameter so that the forward hovering target point of the vessel's bow, that is, the orientation of the vessel's bow is consistent with the direction of the hovering target point, and controls the output of the forward throttle of the vessel according to the forward throttle control parameter to approach the hovering target point and hover at the approaching hovering target point. It can be seen that the present invention realizes the purpose of automatically hovering at a fixed position by adjusting the orientation of the vessel's bow and the output of the forward throttle, thereby avoiding the vessel from moving to a complex external environment due to the action of water flow, which brings great uncertainty and inoperability to subsequent vessel control, and at the same time reducing potential safety hazards.

[0066] It should be noted that in the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments. For the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present invention is not limited by the described order of actions, because according to the present invention, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0067] The above are only the preferred embodiments of the present invention, and do not impose any formal restrictions on the present invention. Those skilled in the art can make various equivalent changes and improvements on the basis of the above embodiments. Any equivalent changes or modifications made within the scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A method for automatic hovering of a ship, characterized in that, Including: Obtain the yaw axis angle information of the vessel, obtain the distance parameter based on the vessel's GPS position information and the position information of the hovering target point, and correct the obtained yaw axis angle information according to the vessel's GPS position information to obtain the yaw axis angle parameter; Calculate the steering throttle control parameter according to the yaw axis angle parameter, and calculate the forward throttle control parameter according to the distance parameter; Control the steering of the vessel according to the steering throttle control parameter so that the bow of the vessel is directly facing the hovering target point, and control the output of the forward throttle of the vessel according to the forward throttle control parameter to approach the hovering target point; Perform a hovering operation after approaching the hovering target point, and maintain the steering throttle control parameter and the forward throttle control parameter at that moment; Wherein, the calculating the steering throttle control parameter according to the yaw axis angle parameter includes: Calculate the angle deviation value between the yaw axis angle parameter and the target angle of the hovering target point; Calculate the steering throttle control parameter according to the angle deviation value to control the steering of the vessel so that its bow is directly facing the hovering target point; The calculating the steering throttle control parameter according to the angle deviation value includes: According to the formula calculate the lateral change linear velocity V of the hull; where T is the preset vessel control period, y is the actual displacement of the hull during travel, Δyaw is the angle deviation value, G is the maximum turning angular velocity of the hull, N is the number of control periods for achieving angle correction, and deg is the true yaw axis angle value that should be corrected by the control in each control period on average; Obtain the corresponding steering throttle control parameter from the hull dynamics or the throttle reference table according to the lateral change linear velocity V of the hull; Or, the calculating the steering throttle control parameter according to the angle deviation value includes: According to the formula the target angular velocity W is calculated; where T is the preset vessel control period, y is the actual displacement of the hull, Δyaw is the angle deviation value, G is the maximum turning angular velocity of the hull, N is the number of control periods for achieving angle correction, and deg is the true yaw axis angle value that should be corrected by the control in each control period on average; Obtain the corresponding steering throttle control parameter from the hull dynamics or the throttle reference table according to the target angular velocity W.

2. The automatic hovering method for a vessel according to claim 1, wherein The calculating the forward throttle control parameter according to the distance parameter includes: Judge whether the distance parameter is less than or equal to a first preset distance, where the first preset distance is the natural sliding distance of the vessel at the maximum speed; If so, calculate the target speed v according to the formula where f is the resultant resistance on the hull, m is the mass of the hull, and d is the remaining distance from the ship to the hovering target point; Obtain the forward throttle control parameter according to the difference between the target speed v and the maximum speed of the vessel.

3. The automatic hovering method for a vessel according to claim 2, wherein The judging whether the distance parameter is less than or equal to the first preset distance further includes: If not, the vessel travels at full throttle.

4. The automatic hovering method for a vessel according to claim 1, characterized in that, After the hovering operation is performed after approaching the hovering target point, it further includes: Judge whether the vessel is in a hovering stable state according to the distance parameter and the yaw axis angle parameter within a preset time t. If so, maintain the steering throttle control parameter and the forward throttle control parameter at this moment.

5. The method for automatically hovering a vessel according to claim 4, wherein The judging whether the vessel is in a hovering stable state according to the distance parameter and the yaw axis angle parameter within a preset time t includes: Sample the distance parameters within the preset time t and form an array L = {L1, L2, L3 ··· L n}; Sample the yaw axis angle parameters within the preset time t and form an array J = {J1, J2, J3 ··· J n}; Judge whether the maximum value of the distance parameter in the array L is less than or equal to a third preset distance, and at the same time calculate the variance of the data J and judge whether the variance is less than a preset threshold; If the maximum value of the distance parameter in the array L is less than or equal to the third preset distance and the variance is less than the preset threshold, the vessel is in a hovering stable state.

6. The method for automatic hovering of a vessel according to claim 4, wherein After the judging whether the vessel is in a hovering stable state according to the distance parameter and the yaw axis angle parameter within a preset time t, it further includes: If not, re-execute the steps of obtaining the yaw axis angle information of the vessel, obtaining the distance parameter according to the vessel's GPS position information and the position information of the hovering target point, and correcting the obtained yaw axis angle information according to the vessel's GPS position information to obtain the yaw axis angle parameter.

7. An automatic hovering system for a vessel, characterized in that, Including: An acquisition unit, configured to acquire the yaw axis angle information of the vessel, and obtain a distance parameter according to the vessel's GPS position information and the position information of the hovering target point; An error correction unit, configured to correct the acquired yaw axis angle information according to the vessel's GPS position information to obtain a yaw axis angle parameter; A calculation unit, configured to calculate a steering throttle control parameter according to the yaw axis angle parameter, and calculate a forward throttle control parameter according to the distance parameter; A control adjustment unit, configured to control the steering of the vessel according to the steering throttle control parameter so that the bow of the vessel faces the hovering target point directly, and then control the output of the forward throttle of the vessel according to the forward throttle control parameter to approach the hovering target point; A hovering maintenance unit, configured to perform a hovering operation after approaching the hovering target point, and maintain the steering throttle control parameter and the forward throttle control parameter at that moment; Wherein, calculating the steering throttle control parameter according to the yaw axis angle parameter includes: Calculating an angle deviation value between the yaw axis angle parameter and the target angle of the hovering target point; Calculating a steering throttle control parameter according to the angle deviation value to control the steering of the vessel so that its bow faces the hovering target point directly; Calculating the steering throttle control parameter according to the angle deviation value includes: According to the formula calculate the lateral change linear velocity V of the hull; where T is the preset vessel control period, y is the actual travel displacement of the hull, Δyaw is the angle deviation value, G is the maximum turning angular velocity of the hull, N is the number of control periods for achieving angle correction, and deg is the true yaw axis angle value that should be corrected by the control in each control period on average; Obtaining a corresponding steering throttle control parameter from the hull dynamics or the throttle reference table according to the lateral change linear velocity V of the hull; Alternatively, calculating the steering throttle control parameter according to the angle deviation value includes: According to the formula the target angular velocity W is calculated; where T is the preset vessel control period, y is the actual displacement of the hull, Δyaw is the angle deviation value, G is the maximum turning angular velocity of the hull, N is the number of control periods for achieving angle correction, and deg is the true yaw axis angle value that should be corrected by the control in each control period on average; Obtaining a corresponding steering throttle control parameter from the hull dynamics or the throttle reference table according to the target angular velocity W.

Images