A dynamic modeling method for fixed-wing UAV shipborne sidearm recovery system

Abstract

The present invention discloses a method for dynamic modeling of a fixed-wing UAV shipborne sidearm recovery system. First, according to the position vector relationship between the ship and the sidearm and between each joint, a dynamic coupling coordinate system suitable for shipborne sidearm motion analysis under complex sea conditions is established; secondly, a kinematic model of the ship and each connecting rod of the sidearm is constructed under the inertial system to obtain the motion state of the ship and each connecting rod in the shipborne sidearm system; then, the force conditions of each node of the shipborne sidearm recovery system are determined; then, the dynamic model of the shipborne sidearm recovery system is constructed by combining generalized Lagrange dynamics and Euler equations. The present invention dynamically couples the 6-degree-of-freedom motion of the ship with the 3-degree-of-freedom motion of the sidearm, designs a method for dynamic modeling of a shipborne sidearm fixed-wing UAV recovery system, realizes accurate modeling of a 9-degree-of-freedom shipborne sidearm system under complex sea conditions, and provides a highly reliable model for shipborne sidearm recovery control.

Description

Technical Field

[0001] The invention relates to the technical field of near-sea surface landing and recovery of unmanned aerial vehicles (UAVs), and mainly designs a dynamics modeling method for a shipborne sidearm recovery system of a fixed-wing UAV. Background Art

[0002] The ship-borne UAV landing and recovery technology is a key innovation to improve the combat effectiveness of the Navy. It not only demonstrates the accuracy of the unmanned control system, but also greatly improves the availability of the combat platform. Through the recovery technology, the UAV can safely return to the ship after completing the mission, and achieve rapid maintenance and redeployment, thereby extending the combat time and enhancing continuous surveillance and rapid response capabilities. In addition, the UAV landing and recovery technology significantly reduces combat costs, reduces dependence on pilot resources, increases the survivability of combat units, and also provides a safer guarantee for the communication of sensitive information. In terms of improving the multi-task execution capability and sustained combat capability of maritime combat forces, the UAV landing and recovery technology provides a solid foundation for the effective use of the Navy's unmanned tactical system.

[0003] The UAV shipborne sidearm recovery system is designed to flexibly launch and recover UAVs with long flight time on space-constrained sea or ground mobile platforms. Its innovative design is compatible with a variety of tactical UAVs, ensuring that the UAV can be quickly deployed and safely recovered from any mobile platform. This design effectively solves the landing problem on platforms with limited space and can greatly optimize the utilization efficiency of existing helicopter decks on small and medium-sized ships. For the landing and recovery technology of near-sea UAVs, existing research has been relatively mature, and methods such as sky hook and collision net recovery have been widely studied. However, these methods mainly focus on a single aspect of UAV flight control, while the requirements for the recovery device are relatively simple, and basically no control processing is performed. Based on this, the present invention proposes a dynamic modeling method for a fixed-wing UAV shipborne sidearm recovery system, aiming to improve the accuracy of the shipborne sidearm system model, which has vital research value and practical significance for realizing accurate docking and coordinated control of UAVs under a moving platform. Summary of the invention

[0004] The purpose of the invention is to solve the problem of coordinated docking control of the shipborne sidearm of a fixed-wing UAV under complex sea conditions, and a dynamic modeling method for a shipborne sidearm recovery system of a fixed-wing UAV is proposed.

[0005] The technical solution of the present application as a whole comprises: a dynamic modeling method for a fixed-wing UAV shipborne sidearm recovery system, wherein the shipborne sidearm recovery system comprises a 6DOF moving ship and a 3DOF mechanical sidearm, wherein the inertial system coordinates are set at sea level, wherein the central axis along the length of the mechanical arm has rotational symmetry, and the center of mass is aligned with the rotation axis, and each connecting rod is a mass symmetrically distributed structure; wherein the modeling method is used to enable the fixed-wing UAV shipborne sidearm to coordinate docking control, and wherein the modeling method comprises the following steps;

[0006] Step 1: Based on the position vector relationship between the moving ship and the mechanical side arm and between the joints, a dynamic coupling coordinate system suitable for the motion analysis of the shipborne side arm under complex sea conditions is established;

[0007] Step 2: Based on the coordinate homogeneous linear transformation method, a kinematic model of the ship and each connecting rod of the side arm in the inertial system is constructed to obtain the motion state of the ship and each connecting rod in the shipborne side arm recovery system;

[0008] Step 3: According to the principle of Newtonian mechanics, considering the motion state of each node in the shipborne side arm system, determine the force condition of each node in the shipborne side arm recovery system;

[0009] Step 4: Combining the system kinematic model described in step 2 with generalized Lagrange dynamics and Euler equations to obtain a side arm dynamics equation under a non-inertial base, and deriving the total kinetic energy of the shipborne side arm recovery system according to the side arm dynamics equation under the non-inertial base;

[0010] Step 5: Based on the force conditions of each node obtained in step 3 and the sidearm dynamics equation under the non-inertial base in step 4, a dynamic model of the shipborne sidearm cooperative docking control is designed.

[0011] Further, the specific process of step one is as follows:

[0012] Select the same sea level coordinate system O as the fixed-wing UAV flight system g -X g Y g Z g ; Select the ship's center of mass as the ship's coordinate origin O b , the bow of the ship points in the direction of the X axis, and the ship's center of mass coordinate system O is established by satisfying the right-hand rule b -X b Y b Z b ; Select the rotation axis direction of the side arm joint as the Z axis, the direction of the connecting rod as the X axis, and satisfy the right-hand rule to establish the rotation coordinate system O1-X1Y1Z1 of the joint one. Similarly, establish the rotation coordinate systems O2-X2Y2Z2 and O3-X3Y3Z3 of the joint two and three respectively.

[0013] Further, the specific process of step 2 is as follows:

[0014] Step 201: Based on the coordinate homogeneous transformation method, derive the transformation matrix of each node relative to the sea level coordinate system;

[0015] Step 202: Based on the transformation matrix of each node obtained in step 201, the kinematic model of each link of the side arm in the sea level coordinate system is expressed by the Jacobian matrix as follows:

[0016]

[0017] Among them, x1, x2, x3 are matrices The X-axis component of the displacement vector, y1, y2, y3 are matrices The Y-axis component of the displacement vector, z1, z2, z3 are matrices The Z-component of the displacement vector;

[0018] Step 203: Based on the transformation matrix of step 201 and the Jacobian matrix of step 202, the spatial velocity of the side arm joint in the inertial system is expressed as

[0019]

[0020] in, Represented as the ship's spatial position, Expressed as the angular velocity of the three-link joint.

[0021] Further, the specific process of step three is as follows:

[0022] Step 301: Considering the gravity of each connecting rod, the gravity of connecting rod 1 relative to the sea level coordinate system can be expressed as

[0023]

[0024] in, is the rotation matrix of the link i coordinate system relative to the sea level coordinate system, P z =

[001] T , is the center of mass of link one in the link one coordinate system.

[0025] Step 302: Calculate the joint torque of each link of the side arm based on the gravity of each link in step 301. The joint torque of link 1 affected by gravity is expressed as

[0026]

[0027] Among them, J1(q) is the displacement vector part of the Jacobian matrix J1, is the adjoint matrix The displacement vector part of the second and third links affected by gravity are expressed as

[0028]

[0029] Among them, J2(q) and J3(q) are the displacement vector parts of the Jacobian matrices J2 and J3 respectively. The adjoint matrices are The displacement vector part of .

[0030] Further, the specific process of step four is as follows:

[0031] Step 401: Combine the generalized Lagrange method and Euler equation to build a dynamic model of the shipborne sidearm recovery system.

[0032]

[0033] Among them, M(Q) is the system inertia matrix, C(Q,v) matrix is ​​expressed as the matrix describing the Coriolis force and centrifugal force acting on the system, τ is the total torque of the system composed of gravity, joint rotation friction and external force vector;

[0034] Step 402: Based on the spatial velocity of each link relative to the sea level coordinate calculated in step 203, derive the total kinetic energy of each link of the side arm relative to the sea level; which is expressed as

[0035]

[0036] Among them, I i =diag(I ix ,I iy ,I iz ,m i ,m i ,m i ) is the positive definite inertia tensor of connecting rod i, and the inertia matrix M i (q) is expressed as

[0037]

[0038] in, is the adjoint matrix of the link i relative to the ship body coordinates;

[0039] The total kinetic energy of the shipborne sidearm system is composed of the connecting rod and the non-inertial base, which is expressed as

[0040]

[0041] Step 403: Based on the total kinetic energy of the system obtained in step 402 and combined with the system dynamics equation in step 401, the dynamics equation of the side arm system under the non-inertial moving platform is written as:

[0042]

[0043] Among them, M VV ∈R 6×6 is the ship motion part of the total inertia matrix M(q) of the sidearm system; M qV ∈R 3×6 is the coupling part of the ship motion and the sidearm motion in the total inertia matrix M(q) of the sidearm system; M qq ∈R 3×3 is the three-link motion part of the total inertia matrix M(q) of the side arm system; C VV ∈R 6×6 ,C Vq ∈R 6×3 ,C qV ∈R 3×6 ,C qq ∈R 3×3 The total Coriolis force and centrifugal force matrix C(Q,v)∈R of the shipborne sidearm system is constructed together 9×9 ; F b It is the unknown external force acting on the ship, and is juxtaposed with the ship's 6-DOF motion.

[0044] Further, the specific process of step five is as follows:

[0045] Step 5: Based on the dynamic equation in step 403 and the gravity torque obtained in step 302, the shipborne side arm dynamic model is constructed, which is specifically expressed as the following equation:

[0046]

[0047] in,

[0048] τ g =[τ1,τ2,τ3] T .

[0049] Compared with the prior art, the present invention has the following obvious advantages:

[0050] (1) A dynamic modeling method for the shipborne sidearm recovery system of a fixed-wing UAV is proposed. The 6-DOF motion of the ship is dynamically coupled with the 3-DOF sidearm, providing a reliable mathematical model for the subsequent UAV collaborative docking control.

[0051] (2) A dynamic modeling method for a fixed-wing UAV shipborne sidearm recovery system is proposed. The non-inertial force exerted by the ship's motion on the sidearm is incorporated into the sidearm model as a disturbance, effectively improving the accuracy of the dynamic model of the shipborne sidearm recovery system under complex sea conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A flow chart of a shipborne sidearm dynamics modeling method provided by the present invention;

[0053] Figure 2 A schematic diagram of the shipborne side arm model and the coordinate systems of each node provided by the present invention;

[0054] Figure 3 The 3DOF side arm schematic and connecting rod parameters provided by the present invention. DETAILED DESCRIPTION

[0055] In order to facilitate those skilled in the art to understand and implement the present invention, the present invention is further described in detail below with reference to the accompanying drawings.

[0056] The present invention discloses a method for dynamic modeling of a fixed-wing UAV shipborne sidearm recovery system, wherein the modeling steps are as follows: Figure 1 As shown in the figure, firstly, according to the multi-rigid body motion characteristics of the ship-sidearm and the position vector relationship between the nodes of the system, a dynamic coupling coordinate system suitable for the motion analysis of the shipborne sidearm under complex sea conditions is established; on this basis, through the homogeneous linear transformation of the coordinates of each node, the kinematic model of the ship and each connecting rod of the sidearm is constructed in the inertial system to obtain the motion state of the ship and each connecting rod in the shipborne sidearm system; then, according to the principle of Newtonian mechanics, considering the motion state of each node in the shipborne sidearm system, the force condition of each node of the shipborne sidearm recovery system is determined; then, combining the generalized Lagrange dynamics and Euler equations, a dynamic model of the shipborne sidearm recovery system is constructed to realize the precise control of the subsequent shipborne sidearm collaborative docking.

[0057] like Figure 3 As shown, in this modeling example, the lengths of the three links of the side arm are set to be l1, l2, and l3, the average masses at the center of mass of the three links are m1, m2, and m3, the moments of inertia are I1, I2, and I3, the rotation angles of each joint are q1, q2, and q3, and the angular velocity is The angular acceleration is Assume the translation displacement of the ship's center of mass relative to the inertial coordinates as P s =[x s ,y s ,z s ] T , the translation speed is The translational acceleration is Assume that the motion of the ship around the center of mass is represented by θ s ,ψ s ,φ s , the angular velocity is p s ,q s ,r s , the angular acceleration is

[0058] like Figure 2 As shown, it is a simplified diagram of the shipborne side arm recovery system of the present invention, and the specific dynamic modeling includes the following steps:

[0059] Step 1: Establish a dynamic coupling coordinate system suitable for shipborne sidearm motion analysis under complex sea conditions. Specifically, select the same sea level coordinate system as the fixed-wing UAV flight system. g -X g Y g Z g ; Select the ship's center of mass as the ship's coordinate origin O b , the bow of the ship points in the direction of the X axis, and the ship's center of mass coordinate system O is established by satisfying the right-hand rule b -X b Y b Z b ; Select the direction of the first rotation axis of the side arm joint as the Z axis, the direction of the connecting rod as the X axis, and satisfy the right-hand rule to establish the first rotation coordinate system O1-X1Y1Z1 of the joint. Similarly, establish the second and third rotation coordinate systems O2-X2Y2Z2 and O3-X3Y3Z3 respectively; at the same time, set q0 as the angle between the projection of the ship hull coordinate axis X on the sea level and the X axis of the sea level coordinate system, which is equivalent to ψ s .

[0060] Step 2: Based on the coordinate homogeneous transformation method, the kinematic model of the ship and each link of the side arm in the inertial system is constructed to obtain the motion state of the ship and each link in the shipborne side arm system, specifically:

[0061] Step 201, based on the homogeneous transformation of coordinates, first, the adjoint matrix of the ship coordinate system relative to the sea level coordinates is in is the rotation matrix between the sea level coordinate system and the ship center of mass coordinate system, which can be expressed as is a skew-symmetric matrix that satisfies The homogeneous transformation matrix from the ship's center of mass to the side arm base joint 1 is in is the rotation matrix from the ship's center of mass coordinates to the joint coordinate system, which can be expressed as is the displacement vector from the ship's center of mass to the sidearm joint 1. The homogeneous transformation matrix from the sidearm joint 1 to the joint 2 is in is the rotation matrix from the side arm joint 1 coordinate system to the joint 2 coordinate system, which can be expressed as is the displacement vector from joint 1 to joint 2. The homogeneous transformation matrix from side arm joint 2 to joint 3 is in is the rotation matrix from the side arm joint two coordinate system to the joint three coordinate system, which can be expressed as is the displacement vector from joint 2 to joint 3.

[0062] Step 202: Based on step 201, calculate the kinematic equations of each joint of the side arm relative to the ship's center of mass. First, the homogeneous transformation matrix of the joint relative to the ship's center of mass can be expressed as Similarly, the homogeneous transformation matrix of joint 2 relative to the ship's center of mass coordinates is The homogeneous transformation matrix of joint three relative to the ship's center of mass coordinates is:

[0063]

[0064] Secondly, the Jacobian matrices of each joint relative to the ship's center of mass can be expressed as J1, J2, and J3, respectively, which are specifically described as:

[0065]

[0066] Among them, x1, x2, x3 are matrices The X-axis component of the displacement vector, y1, y2, y3 are matrices The Y-axis component of the displacement vector, z1, z2, z3 are matrices The Z-component of the displacement vector;

[0067] Step 203: Based on the transformation matrix calculated in steps 201 and 202, the spatial velocity of each joint relative to the sea level is calculated to achieve the coupling of the 6-DOF ship motion and the 3-DOF sidearm motion. The spatial velocity of the joint in the inertial system can be expressed as The spatial velocity of the joint in the second and third inertial systems can be expressed as in, Represented as the ship's spatial position, Expressed as the angular velocity of the three-link joint.

[0068] Step 3: According to the principles of Newtonian mechanics, consider the motion state of each node in the shipborne sidearm system and determine the force conditions of each node in the shipborne sidearm recovery system.

[0069] Step 301: First consider the gravity of each connecting rod. The gravity of connecting rod 1 relative to the sea level coordinate system can be expressed as in is the rotation matrix of the link coordinate system relative to the sea level coordinate system, where P z =

[001] T , To represent the center of mass of Link 1 in Link 1 coordinate system, in this modeling example, we choose It is located at the origin of the coordinate system of link 1 to simplify the calculation; the gravity of link 2 and link 3 relative to the sea level coordinate system can be expressed as in They are the rotation matrices of the second and third coordinate systems of the connecting rod relative to the sea level coordinate system.

[0070] Step 302: Calculate the joint torque of each link of the side arm based on the relative sea level coordinate gravity of each link calculated in step 301. The joint torque of the link affected by gravity is expressed as Among them, J1(q) is the displacement vector part of the Jacobian matrix J1, is the adjoint matrix The displacement vector part of the second and third links affected by gravity are expressed as J2(q) and J3(q) are the displacement vector parts of the Jacobian matrices J2 and J3 respectively. The adjoint matrices are The displacement vector part of .

[0071] Step 4: Combine the generalized Lagrange method and Euler equation to build a dynamic model of the shipborne sidearm recovery system, specifically:

[0072] Step 401: The generalized Lagrange method gives a set Q = {Q i The kinetic equations of a general rigid body described by the configuration are given by the following generalized representation of the coordinates of a rigid body: Where M(Q) is the inertia matrix of the system constructed in state Q; the entire rigid body dynamics equation can be expressed as

[0073]

[0074] Among them, M(Q) is the system inertia matrix, C(Q,v) matrix is ​​the matrix describing the Coriolis force and centrifugal force acting on the system, and τ is the total torque composed of gravity, joint rotation friction and external force vector.

[0075] Step 402: In this modeling example, take Q = {x s ,y s ,z s ,θ s ,ψ s ,φ s ,q1,q2,q3} construct the system state and take As the velocity vector state; according to the spatial velocity of each link relative to the sea level coordinate calculated in step 203, the total kinetic energy of each link of the side arm relative to the sea level is derived. It can be expressed as

[0076]

[0077] Among them, I i =diag(I ix ,I iy ,I iz ,m i ,m i ,m i ) is the positive definite inertia tensor of connecting rod i, and the inertia matrix M i (q) is expressed as

[0078]

[0079] in, is the adjoint matrix of the link i relative to the ship body coordinates.

[0080] The total kinetic energy of the shipborne sidearm system is composed of the connecting rod and the non-inertial base, which can be expressed as Considering E k,total (q,v) and the sum of the inertia matrices of the links M(q) do not depend on the ship's position and therefore do not depend on the inertial reference frame O g -X g Y g Z g choice.

[0081] Step 403: Based on the total kinetic energy of the system obtained in step 402 and combined with the system dynamics equation in step 401, the dynamics equation of the shipborne sidearm system can be written as:

[0082]

[0083] Among them, M VV ∈R 6×6 is the ship motion part of the total inertia matrix M(q) of the sidearm system; M qV ∈R 3×6 is the coupling part of the ship motion and the sidearm motion in the total inertia matrix M(q) of the sidearm system; M qq ∈R 3×3 is the three-link motion part of the total inertia matrix M(q) of the side arm system; C VV ∈R 6×6 ,C Vq ∈R 6×3 ,C qV ∈R 3×6 ,C qq ∈R 3×3 Together they constitute the total Coriolis force and centrifugal force matrix C(Q,v)∈R of the shipborne sidearm system 9×9 ; F b It is the unknown external force acting on the ship, and is juxtaposed with the ship's 6-DOF motion.

[0084] Step 5: Consider the position of the ship relative to the sea level coordinates speed and acceleration All of them can be obtained through measurement, so it is assumed that the motion of the ship is completely determined by external forces to simplify the dynamic equations. Since the sidearm is smaller than the ship, it is assumed in this modeling example that the torque generated by the internal joints of the sidearm will not affect the motion of the ship.

[0085] Based on the above assumptions, the dynamic equation of the shipborne sidearm system can only consider the second row of the dynamic equation in step 403, and combine the gravity moment obtained in step 302 to complete the construction of the shipborne sidearm dynamic model, which is specifically expressed as the following equation:

[0086]

[0087] in, Together they constitute the non-inertia force moment exerted by the ship's motion on the side arm; M qq is the inertia matrix of the side arm, C qq is the matrix composed of the Coriolis force and centrifugal force on the side arm, which is specifically expressed as

[0088]

[0089] Among them, C qV is the matrix composed of the Coriolis force and centrifugal force caused by the ship's motion exerting non-inertial force on the side arm, which is specifically expressed as

[0090]

[0091] in, τ g =[τ1,τ2,τ3] T .

[0092] A dynamic modeling method for a fixed-wing UAV ship sidearm recovery system provided by the present invention is based on the ship motion characteristics under complex sea conditions and the actual rotation characteristics of the three-link sidearm, takes into account the non-inertial force exerted on the sidearm by the ship motion and adopts an improved generalized Lagrange method for modeling, which effectively improves the model accuracy and lays a foundation for subsequent terminal stability control experiments of the sidearm.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Several modifications and changes may be made without departing from the principles of the present invention. These improvements and detailed adjustments should also be considered to be within the scope of protection of the present invention.

Claims

1. A dynamic modeling method for a fixed-wing UAV shipborne sidearm recovery system, wherein the shipborne sidearm recovery system comprises a 6DOF moving ship and a 3DOF mechanical sidearm, wherein the inertial system coordinates are set at sea level, the central axis of the mechanical arm along its length has rotational symmetry, and the center of mass is aligned with the rotation axis, and each connecting rod is a mass symmetrically distributed structure; the modeling method is used to enable the fixed-wing UAV shipborne sidearm to coordinate docking control, and is characterized in that: The modeling method comprises the following steps: Step 1: Based on the position vector relationship between the moving ship and the mechanical side arm and between the joints, a dynamic coupling coordinate system suitable for the motion analysis of the shipborne side arm under complex sea conditions is established; Step 2: Based on the coordinate homogeneous linear transformation method, a kinematic model of the ship and each connecting rod of the side arm in the inertial system is constructed to obtain the motion state of the ship and each connecting rod in the shipborne side arm recovery system; Step 3: According to the principle of Newtonian mechanics, considering the motion state of each node in the shipborne side arm system, determine the force condition of each node in the shipborne side arm recovery system; Step 4: Combining the kinematic model described in step 2 with generalized Lagrange dynamics and Euler equations to obtain a side arm dynamics equation under a non-inertial base, and deriving the total kinetic energy of the shipborne side arm recovery system according to the side arm dynamics equation under the non-inertial base; Step 5: Based on the force conditions of each node obtained in step 3 and the sidearm dynamics equation under the non-inertial base in step 4, a dynamic model of the shipborne sidearm cooperative docking control is designed.

2. According to claim 1, a fixed-wing UAV shipborne side arm recovery system dynamics modeling method is characterized in that: The specific process of step one is as follows: Select the same sea level coordinate system O as the fixed-wing UAV flight system g -X g Y g Z g ; Select the ship's center of mass as the ship's coordinate origin O b , the bow of the ship points in the direction of the X axis, and the ship's center of mass coordinate system O is established by satisfying the right-hand rule b -X b Y b Z b ; Select the rotation axis direction of the side arm joint as the Z axis, the direction of the connecting rod as the X axis, and satisfy the right-hand rule to establish the rotation coordinate system O1-X1Y1Z1 of the joint one. Similarly, establish the rotation coordinate systems O2-X2Y2Z2 and O3-X3Y3Z3 of the joint two and three respectively.

3. The method for dynamic modeling of a fixed-wing UAV shipborne sidearm recovery system according to claim 2 is characterized in that: The specific process of step 2 is as follows: Step 201: Based on the coordinate homogeneous transformation method, derive the transformation matrix of each node relative to the sea level coordinate system; Step 202: Based on the transformation matrix of each node obtained in step 201, the kinematic model of each link of the side arm in the sea level coordinate system is expressed by the Jacobian matrix as follows: Among them, x1, x2, x3 are matrices The X-axis component of the displacement vector, y1, y2, y3 are matrices The Y-axis component of the displacement vector, z1, z2, z3 are matrices The Z-axis component of the displacement vector; q1, q2, q3 are the rotation angles of each joint of the side arm; Step 203: Based on the transformation matrix of step 201 and the Jacobian matrix of step 202, the spatial velocity of the side arm joint in the inertial system is expressed as in, Represented as the ship's spatial position, Expressed as the angular velocity of the three-link joint; It is the homogeneous transformation matrix from the inertial system to the ship's center of mass coordinates.

4. The method for dynamic modeling of a fixed-wing UAV shipborne sidearm recovery system according to claim 3 is characterized in that: The specific process of step three is as follows: Step 301: Considering the gravity of each connecting rod, the gravity of connecting rod 1 relative to the sea level coordinate system can be expressed as in, is the rotation matrix of the link i coordinate system relative to the sea level coordinate system, P z =[001] T , is the center of mass of link 1 in link 1 coordinate system; is the ship inertial system rotation matrix, is the rotation matrix of the i-th joint of the sidearm in the hull coordinate system; m i is the mass of the i-th connecting rod; Step 302: Based on the gravity of each connecting rod in step 301, calculate the joint torque of each connecting rod of the side arm; the joint torque of connecting rod 1 affected by gravity is expressed as Among them, J1(q) is the displacement vector part of the Jacobian matrix J1, is the adjoint matrix The displacement vector part of the second and third links affected by gravity are expressed as Among them, J2(q) and J3(q) are the displacement vector parts of the Jacobian matrices J2 and J3 respectively. The adjoint matrices are The displacement vector part of .

5. The method for dynamic modeling of a fixed-wing UAV shipborne sidearm recovery system according to claim 4 is characterized in that: The specific process of step 4 is as follows: Step 401: Combine the generalized Lagrange method and Euler equation to build a dynamic model of the shipborne sidearm recovery system. Where M(Q) is the system inertia matrix, C(Q,v) is the matrix describing the Coriolis force and centrifugal force on the system, τ is the total torque of the system composed of gravity, joint rotation friction and external force vector; v and are the velocity and acceleration of the shipborne sidearm system in the inertial system respectively; Step 402: Based on the spatial velocity of each link relative to the sea level coordinate calculated in step 203, derive the total kinetic energy of each link of the side arm relative to the sea level; which is expressed as Among them, I i =diag(I ix ,I iy ,I iz ,m i ,m i ,m i ) is the positive definite inertia tensor of connecting rod i, and the inertia matrix M i (q) is expressed as in, is the adjoint matrix of the link i relative to the ship body coordinates; The total kinetic energy of the shipborne sidearm system is composed of the connecting rod and the non-inertial base, which is expressed as Step 403: Based on the total kinetic energy of the system obtained in step 402 and combined with the system dynamics equation in step 401, the dynamics equation of the side arm system under the non-inertial moving platform is written as: Among them, M VV ∈R 6×6 is the ship motion part of the total inertia matrix M(q) of the sidearm system; M qV ∈R 3×6 is the coupling part of the ship motion and the sidearm motion in the total inertia matrix M(q) of the sidearm system; M qq ∈R 3×3 is the three-link motion part of the total inertia matrix M(q) of the side arm system; C VV ∈R 6×6 ,C Vq ∈R 6×3 ,C qV ∈R 3×6 ,C qq ∈R 3×3 The total Coriolis force and centrifugal force matrix C(Q,v)∈R of the shipborne sidearm system is constructed together 9×9 ; F b It is the unknown external force acting on the ship, and is juxtaposed with the ship's 6-DOF motion.

6. The method for dynamic modeling of a fixed-wing UAV shipborne sidearm recovery system according to claim 5 is characterized in that: The specific process of step five is as follows: Step 5: Based on the dynamic equation in step 403 and the joint torque obtained in step 302, the shipborne side arm dynamic model is constructed, which is specifically expressed as the following equation: in, t g =[τ1,τ2,τ3] T 。

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