A ship navigation attitude control device and method based on the MAGNUS principle

Abstract

The application provides a ship navigation attitude control device and method based on the MAGNUS principle, wherein step 1 is to construct a catamaran longitudinal motion model by adopting a slice theory; step 2 is to convert the catamaran longitudinal motion model into a state space form; and step 3 is to input ship attitude signals acquired by a navigation attitude instrument into the catamaran longitudinal motion model to acquire a supporting rotor rotating speed and realize resistance to waves. The ship longitudinal attitude control device based on the MAGNUS effect can not only solve the problem of ship longitudinal motion, but also enhance the rigidity of the ship structure. Meanwhile, the front and rear attitude control systems form a frame structure with the catamaran, and the structural strength of the catamaran is greatly enhanced.

Description

Technical Field

[0001] This invention relates to the field of ship roll reduction technology, and in particular to a ship navigation attitude control device and method based on the MAGNUS principle. Background Technology

[0002] Small waterplane area catamarans (SWAs) are a new type of high-performance vessel whose upper hull is supported by several streamlined struts on two torpedo-shaped submerged hulls. They are named for their small waterline area. Compared to conventional monohulls of the same tonnage, they offer excellent seakeeping and a large deck. However, this small waterline area presents two challenges. First, during SWATH operations, the hull may bury its bow due to the munk moment on the submerged hulls. This can lead to longitudinal instability, high-speed bow lifting, and even loss of normal navigation ability as speed increases. Second, it results in insufficient overall hull rigidity, necessitating a complex hull structure design to meet strength requirements.

[0003] Currently, the solutions to longitudinal instability and severe longitudinal motion in waves during SWATH navigation, both domestically and internationally, involve installing stabilizing fins. This involves installing a pair of controllable stabilizing fins on each side of the submersible, near the bow and stern. Stabilizing fins generate lift based on airfoil principles and control the ship's attitude through specific methods. However, the lift coefficient of stabilizing fins is relatively small, requiring large-area stabilizing fin devices to achieve good attitude control. This results in high installation costs and increases the mass of external appendages. Furthermore, the presence of four fins on the submersible complicates the overall load distribution, further increasing the structural design complexity. Summary of the Invention

[0004] Specifically, this invention proposes a ship navigation attitude control method based on the MAGNUS principle, which includes the following steps;

[0005] Step 1: Construct a longitudinal motion model of the catamaran using slice theory;

[0006] Step 2: Convert the longitudinal motion model of the catamaran into a state-space form;

[0007] Step 3: Input the ship attitude signal obtained by the attitude and bearing system into the longitudinal motion model of the catamaran to obtain the rotational speed of the support rotor and achieve wave resistance.

[0008] Furthermore, in step 1, the linear equations of the catamaran motion model are:

[0009]

[0010] Where M represents the mass of the ship, I5 represents the moment of inertia about the transverse axis y passing through the ship's center of gravity; ξ3 and ξ5 represent the ship's heave and pitch displacements, respectively; Aik B ik C ik (i, k = 3, 5) represent the generalized added mass, damping coefficient, and restoring force coefficient, respectively; the subscripts 3 and 5 represent the heave and pitch motion modes, respectively; F3 and F5 are the complex amplitude values ​​of the external disturbance force and torque, respectively.

[0011] Furthermore, in step 1, considering the influence of the control force and torque generated by installing this device on the ship's motion, the longitudinal motion model of the catamaran is as follows:

[0012]

[0013] F y To support the lift of the rotor, FM supports the torque of the rotor relative to the center of gravity.

[0014] Furthermore, in step 2, the longitudinal motion model of the catamaran is converted into a state-space form as follows:

[0015]

[0016] And set:

[0017]

[0018]

[0019]

[0020]

[0021] F = [F3 0 F5 0] T ;

[0022] ω=[ω1 ω2] T ;

[0023] get:

[0024]

[0025] Where ω1 is the rotational speed of the bow support rotor, ω2 is the rotational speed of the stern support rotor; ρ is the incoming flow density, U0 is the incoming flow velocity, R is the radius of the support rotor, L is the length of the support rotor, P1 is the longitudinal distance between the bow support rotor and the ship's center of gravity, and P2 is the longitudinal distance between the stern support rotor and the ship's center of gravity.

[0026] A ship navigation attitude control device based on the MAGNUS principle is also provided, which includes a main control box, a forward attitude control device and a rear attitude control device.

[0027] The forward attitude control device is located at the bow of the catamaran, and the aft attitude control device is located at the stern of the catamaran.

[0028] The forward attitude control device and the aft attitude control device are attitude control devices with the same structure. The attitude control device has a drive part installed on one side and a simple support part installed on the other side in the port and starboard compartments of the catamaran. The drive part and the simple support part are used to jointly drive and support the rotor.

[0029] The drive unit includes a servo motor and a drive shaft, and the servo motor drives the rotor through the drive shaft.

[0030] The main control box generates rotation signals to drive the servo motors based on the ship's attitude.

[0031] The simply supported portion includes a drive shaft for supporting the rotor.

[0032] Furthermore, the drive unit also includes a gearbox, the input end of which is connected to the servo motor via a flange, and the output end of which is connected to the drive shaft via a spline; the gearbox is used to amplify the torque output by the servo motor.

[0033] Furthermore, the drive unit also includes a support assembly, which is welded and fixed to the hull and horizontally arranged in a suitable position in the cabin, while the support assembly is fixedly connected to the gearbox.

[0034] Furthermore, the drive unit also includes a seawater sealing assembly disposed near the outboard portion of the support assembly to prevent seawater from penetrating the compartment.

[0035] Furthermore, the simply supported section is located opposite the hull where the drive section is located. The simply supported section does not contain a servo motor or gearbox, and its remaining structure is the same as that of the drive section.

[0036] Furthermore, the relationship between the ship's attitude and the rotation signal is as follows:

[0037]

[0038] in, F = [F3 0 F5 0] T , ω=[ω1 ω2] T ,

[0039]

[0040] ω1 is the rotational speed of the bow-supported rotor, and ω2 is the rotational speed of the stern-supported rotor; M represents the mass of the ship, and I5 represents the moment of inertia about the transverse axis y passing through the ship's center of gravity; ξ3 and ξ5 represent the ship's heave and pitch displacements, respectively; Aik B ik C ik (i, k = 3, 5) represent the generalized added mass, damping coefficient, and restoring force coefficient, respectively; the subscripts 3 and 5 represent the heave and pitch motion modes, respectively; F3 and F5 are the complex amplitude values ​​of the external disturbance force and torque, respectively; ρ is the incoming flow density, U0 is the incoming flow velocity, R is the radius of the supporting rotor, L is the length of the supporting rotor, P1 is the longitudinal distance between the bow supporting rotor and the ship's center of gravity, and P2 is the longitudinal distance between the stern supporting rotor and the ship's center of gravity.

[0041] The beneficial effects achieved by this invention are:

[0042] The present invention proposes a ship longitudinal attitude control device based on the MAGNUS effect, which can not only solve the problem of ship longitudinal motion, but also enhance the rigidity of the ship structure.

[0043] The ship longitudinal attitude control device based on the MAGNUS effect proposed in this invention, when the incoming flow velocity is the same and the rotor is rotating, generates lift through the MAGNUS effect. At an appropriate circumferential velocity ratio, the lift coefficient of this device is 3 to 5 times that of the stabilizing fin, which generates lift based on the airfoil principle. This results in an equivalent ship attitude control effect, while the projected area of ​​this device is only about 1 / 3 that of the stabilizing fin device. Therefore, using this device can significantly reduce the volume and mass of external appendages, lower the cost of ship attitude control, and demonstrates certain technological advancements and economic benefits.

[0044] This device connects two hollow rotors, one at the bow and one at the stern, to the two submerged hulls. The rotors are mounted and supported by a support structure fixed to the hull structure. Driven by a servo motor and a reducer, the rotors can rotate rapidly in both directions. When the ship is sailing, the Magnus effect generates lift perpendicular to the incoming current. The main control box controls the rotors, changing their speed and direction to alter the magnitude and direction of the lift, thereby controlling the ship's trim, pitch, and heave. For example, rotating the forward rotor clockwise generates downward lift, while rotating the aft rotor counterclockwise generates upward lift, creating a moment that causes the ship to bow, reducing the bow-raising attitude at high speeds. Simultaneously, because the rotors connect the two hulls at the bow and stern, the overall strength of the catamaran, including lateral and torsional strength, is significantly increased, greatly reducing the complexity of the structural design.

[0045] Meanwhile, the forward and aft attitude control systems are rigidly connected to both appendages of the catamaran, forming a frame structure that can significantly enhance the structural strength of the catamaran and reduce the difficulty of its structural design. Attached Figure Description

[0046] Figure 1A schematic diagram illustrating the lift generation of a ship navigation attitude control device based on the MAGNUS principle, provided for an embodiment of the present invention;

[0047] Figure 2 A schematic diagram of a ship navigation attitude control device based on the MAGNUS principle provided for an embodiment of the present invention;

[0048] Figure 3 A schematic diagram of the drive section in a ship navigation attitude control device based on the MAGNUS principle, provided for an embodiment of the present invention;

[0049] Figure 4 A schematic diagram of the simply supported part in a ship navigation attitude control device based on the MAGNUS principle provided in an embodiment of the present invention;

[0050] Figure 5 A schematic diagram illustrating the principle of a ship navigation attitude control method based on the MAGNUS principle, provided for an embodiment of the present invention;

[0051] Figure 6 This is a control diagram illustrating a ship navigation attitude control method based on the MAGNUS principle, provided as an embodiment of the present invention.

[0052] 1-Main control box, 2-Servo motor, 3-Gearbox, 4-Drive shaft, 5-Support base assembly, 6-Seawater sealing assembly, 7-Support rotor. Detailed Implementation

[0053] The technical solution of the present invention will be described in more detail below with reference to the accompanying drawings. The present invention includes, but is not limited to, the following embodiments.

[0054] Example 1

[0055] As attached Figure 1-4 As shown, this invention proposes a ship navigation attitude control device based on the MAGNUS principle. In order to realize the role of this attitude control device in improving the longitudinal stability of the catamaran, a forward attitude control device and a rear attitude control device, as well as a main control box 1 for control, need to be installed at appropriate locations at the bow and stern of the catamaran, respectively.

[0056] The forward attitude control device and the aft attitude control device use the same attitude control device structure. The attitude control device has a drive unit installed on one side of the port and starboard compartments of the catamaran, and a simple support unit installed on the other side, which together drive and support the rotor 7. The drive unit includes a servo motor 2, a gearbox 3, a drive shaft 4, a support base assembly 5, and a seawater sealing assembly 6.

[0057] The main control box 1 is located in the drive section installation compartment. The main control box 1 senses the ship's attitude signal through the attitude instrument, and the control system in the main control box 1 analyzes the signal to generate a rotation signal for driving the servo motor 2.

[0058] Servo motor 2 is electrically connected to main control box 1 and outputs a rotation signal.

[0059] The gearbox 3 is connected to the servo motor 2 via a flange. The gearbox 3 is used to reduce the output speed of the servo motor 2 and amplify the torque.

[0060] The drive shaft 4 transmits torque to the gearbox 3 via splines, and the drive shaft 4 is mounted and positioned in the support assembly 5 via two pairs of rolling bearings.

[0061] The support assembly 5 is welded to the hull and horizontally arranged in a suitable position in the compartment. At the same time, the support assembly 5 is fixedly connected to the gearbox 3.

[0062] The seawater sealing assembly 6 is located near the outer side of the support assembly 5 to prevent seawater from entering the compartment.

[0063] The rotor 7 is a hollow structure that is connected to the drive shaft 4 and rotates synchronously.

[0064] The simple support part of the attitude control device is installed in another compartment, excluding the main control box 1, servo motor 2, gearbox 3 and other drive components, the rest of the part is exactly the same as the drive part.

[0065] Example 2

[0066] This embodiment provides a ship navigation attitude control method based on the MAGNUS principle, which is based on the ship navigation attitude control device in Embodiment 1.

[0067] The Magnus rotor is a device that generates lift using the Magnus effect. The Magnus effect refers to the phenomenon that when a rotating cylinder is placed in a flow field, due to viscosity, the rotating boundary layer on the cylinder surface causes the flow velocity to increase on the side where the incoming flow direction is the same as the linear velocity direction of the cylinder surface. According to Bernoulli's equation, the pressure on this side will decrease. On the side opposite to the incoming flow direction, the flow velocity decreases and the pressure increases, generating lift perpendicular to the incoming flow direction.

[0068] As attached Figure 5 As shown, according to Joukowski's theorem, the component of the resultant force in the direction of the incoming flow is called drag, and the component perpendicular to the incoming flow is called lift. The calculation is as follows:

[0069]

[0070]

[0071] Among them, Fx As resistance, F y For lift;

[0072] The angular velocity of the supporting rotor is: v θ =Rω

[0073] The corresponding point vortex circulation quantity is: Γ=2πR*v θ =2πR 2 ω

[0074] Therefore, the lift force supporting the rotor is: F y =2πρR 2 U0ω

[0075] Where R represents the radius of the supporting rotor, ω represents the rotational speed of the supporting rotor, ρ represents the incoming flow density, U0 represents the incoming flow velocity, and p represents the longitudinal distance between the supporting rotor and the center of gravity of the ship.

[0076] That is, for a cylindrical support rotor of length L and longitudinal distance p from the ship's center of gravity, the lift on the support rotor is mainly positively correlated with the incoming flow velocity U0 and the rotational speed ω of the support rotor. In other words, the lift on a certain cylinder is:

[0077] F y =K1U0ω, K1=2πρR 2 L

[0078] F M =K2U0ω,K2=2πρR 2 Lp

[0079] Where K1 represents the lift calculation parameter, K2 represents the torque calculation parameter, and F M This represents the torque of the rotor relative to its center of gravity.

[0080] Catamaran control equation modeling

[0081] In this embodiment, taking the small waterplane area (SWATH) catamaran as an example, the following steps are included:

[0082] Step 1: Model using slice theory.

[0083] The linear equation for the longitudinal motion of the SWATH ship is:

[0084]

[0085] In the above formula, subscripts 3 and 5 represent the heave and pitch motion modes, respectively; M (unit kg) and I5 (unit Nm) are the mass of the ship and its moment of inertia about the transverse axis y passing through the ship's center of gravity, respectively; ξ3 and ξ5 represent the heave and pitch displacements of the ship, respectively; A ik B ik C ik(i, k = 3, 5) represent the generalized additional mass, damping coefficient, and restoring force coefficient, respectively; F3 and F5 are the complex amplitude values ​​of the external disturbance force and torque, respectively.

[0086] Considering the influence of the control force and torque generated by the installation of this device on the ship's motion, the longitudinal (heave and pitch) motion model of the SWATH ship sailing in random waves is expressed as follows:

[0087]

[0088] Step 2, write the longitudinal motion model of the SWATH ship in state-space form:

[0089]

[0090] Further orders:

[0091]

[0092]

[0093]

[0094]

[0095] F = [F3 0] F 50] T ;

[0096] ω=[ω1 ω2] T ;

[0097] Where ω1 is the rotational speed of the bow-supported rotor, and ω2 is the rotational speed of the stern-supported rotor. Then we have: Multiply both sides by M -1 ,but:

[0098]

[0099] Let: A = M -1 N; B = -M -1 H, then we have:

[0100]

[0101] Step 3: Input the ship attitude signal obtained by the attitude and bearing system into the longitudinal motion model of the catamaran to obtain the rotational speed of the support rotor and achieve wave resistance.

[0102] As attached Figure 6As shown, when a ship is navigating in waves and experiences pitching, the control system can change the speed and direction of the support rotor in real time according to the changes in wave frequency and the ship's current attitude. This can change the magnitude and direction of the lift in real time, thereby generating a torque to resist the wave torque, thus achieving the purpose of reducing pitching and controlling the ship's longitudinal navigation attitude.

[0103] This invention is not limited to the specific embodiments described above. Those skilled in the art can implement this invention using various other specific embodiments based on the disclosed content of the embodiments and accompanying drawings. Therefore, any design that adopts the design structure and concept of this invention and makes some simple changes or modifications falls within the protection scope of this invention.

Claims

1. A method for controlling the sailing attitude of a ship based on the MAGNUS principle, characterized in that, The ship navigation attitude control method includes the following steps; Step 1: Construct a longitudinal motion model of the catamaran using slice theory; Step 2: Convert the longitudinal motion model of the catamaran into a state-space form; Step 3: Input the ship attitude signal obtained by the attitude and bearing system into the longitudinal motion model of the catamaran to obtain the support rotor speed and achieve wave resistance; In step 1, the linear equations of the catamaran motion model are: ； Where M represents the mass of the ship, This represents the moment of inertia about the transverse axis y passing through the ship's center of gravity; and These represent the ship's heave and pitch displacements, respectively. , , i=3,5, k=3,5, representing the generalized added mass, damping coefficient, and restoring force coefficient, respectively; the subscripts 3 and 5 represent the heave and pitch motion modes, respectively. and These are the complex amplitude values ​​of the external disturbance force and torque, respectively; Considering the influence of the control force and torque generated by installing this device on the ship's motion, the longitudinal motion model of the catamaran is as follows: ； To support the lift of the rotor, The torque that supports the rotor relative to its center of gravity; In step 2, the longitudinal motion model of the catamaran is converted into a state-space form as follows: ； And set: ； ； ； ； ； ； get: ； in, To support the rotor speed at the bow, To support the rotor speed at the stern; For the incoming flow density, For the incoming flow velocity, To support the rotor radius, To support the rotor length, The longitudinal distance between the bow rotor and the ship's center of gravity. The longitudinal distance between the stern-supporting rotor and the ship's center of gravity.

2. A ship navigation attitude control device based on the MAGNUS principle of the ship navigation attitude control method of claim 1, characterized in that, The ship navigation attitude control device includes a main control box (1), a forward attitude control device and a rear attitude control device; The forward attitude control device is located at the bow of the catamaran, and the aft attitude control device is located at the stern of the catamaran. The forward attitude control device and the aft attitude control device are attitude control devices with the same structure. The attitude control device has a drive part installed on one side and a simple support part installed on the other side in the left and right compartments of the catamaran. The drive part and the simple support part are used to jointly drive and support the rotor (7). The drive unit includes a servo motor (2) and a drive shaft (4), and the servo motor (2) drives the rotor (7) through the drive shaft (4). The main control box (1) generates a rotation signal to drive the servo motor (2) based on the ship's attitude; The simply supported portion includes a drive shaft (4) for supporting the rotor (7).

3. The ship navigation attitude control device according to claim 2, characterized in that, The drive section also includes a gearbox (3), the input end of which is connected to the servo motor (2) via a flange, and the output end is connected to the drive shaft (4) via a spline; the gearbox (3) is used to amplify the torque output by the servo motor (2).

4. The ship navigation attitude control device according to claim 3, characterized in that, The drive unit also includes a support assembly (5), which is welded and fixed to the hull and horizontally arranged in a suitable position in the cabin. At the same time, the support assembly (5) is fixedly connected to the gearbox (3).

5. The ship navigation attitude control device according to claim 4, characterized in that, The drive unit also includes a seawater sealing assembly (6), which is located on the support assembly (5) near the outboard portion to prevent seawater from penetrating the compartment.

6. The ship navigation attitude control device according to any one of claims 2-5, characterized in that, The simply supported section is located opposite the hull where the drive section is located. The simply supported section does not contain the servo motor (2) and gearbox (3), and the rest of the structure is the same as the drive section.

7. The ship navigation attitude control device according to claim 2, characterized in that, The relationship between the rotation signal output by the main control box (1) and the ship's attitude is as follows: ； in, , , , , , , ； To support the rotor speed at the bow, The rotor speed is supported at the stern; M represents the mass of the ship. This represents the moment of inertia about the transverse axis y passing through the ship's center of gravity; and These represent the ship's heave and pitch displacements, respectively. , , i=3,5, k=3,5, representing the generalized added mass, damping coefficient, and restoring force coefficient, respectively; the subscripts 3 and 5 represent the heave and pitch motion modes, respectively. and These are the complex amplitude values ​​of the external disturbance force and torque, respectively; For the incoming flow density, For the incoming flow velocity, To support the rotor radius, To support the rotor length, The longitudinal distance between the bow rotor and the ship's center of gravity. The longitudinal distance between the stern-supporting rotor and the ship's center of gravity.

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