A method for controlling the elastic pre-set performance of a shipborne stable platform active wave compensation

Abstract

This invention discloses a method for active wave compensation elastic preset performance control of a shipborne stabilization platform, comprising the following steps: designing an elastic performance function; designing an error transformation function; and designing an active wave compensation elastic preset performance control law for the shipborne stabilization platform. By designing the active wave compensation elastic preset performance control law for the shipborne stabilization platform, this invention enables the closed-loop control system to asymptotically stabilize, ensuring that the tracking error always meets the preset control performance constraints, thus significantly improving control accuracy. Furthermore, by designing the elastic performance function, this invention achieves smooth relaxation and flexible pullback of the boundary when the error exceeds the limit, avoiding potential singularity problems. Compared with existing schemes that require the introduction of an auxiliary dynamic system to handle constraints or saturation problems, this invention's method relies solely on algebraic operations without introducing a dynamic system, making it not only simpler and more convenient to implement in engineering applications but also enabling immediate response to these factors without delay.

Description

Technical Field

[0001] This invention relates to equipment control technology in the field of shipbuilding and marine engineering, and in particular to a method for controlling the active wave compensation elastic preset performance of a shipborne stabilization platform. Background Technology

[0002] Shipborne stabilization platforms play a crucial role in ensuring the stability and safety of maritime operations. Under the continuous disturbances of the marine environment, such as wind, waves, and currents, ships inevitably experience six degrees of freedom of motion—including roll, pitch, bow roll, sway, heave, and heave. These complex motions directly affect the normal operation of precision equipment or working devices on board. Through its compensation mechanism, the stabilization platform can actively counteract or significantly reduce the vibrations and displacements caused by the ship's motion, thereby providing a relatively stable reference environment for critical equipment and ensuring the smooth and precise execution of maritime missions.

[0003] The shipborne helicopter lifting and stabilization platform proposed in Chinese patent CN111619816A, with a core structure of multiple hydraulic cylinders and ball joint sleeves, can achieve six-directional spatial movement of the moving platform, effectively compensating for the multi-dimensional motion of the ship. The platform's structural design is quite innovative, ensuring stability without modifying the existing main platform structure. However, this solution only focuses on mechanical structural improvements and does not delve into the design of control algorithms, nor does it provide a targeted solution for dynamic control problems under complex sea conditions.

[0004] Chinese patent CN105094165A proposes a piezoelectric Stewart active platform combining PI force feedback and RLS adaptive feedforward composite control to achieve wide-band, high-precision vibration suppression. However, this method does not consider pre-designed performance and lacks a flexible boundary adjustment mechanism when errors exceed limits. It relies solely on the composite control of PI force feedback and RLS adaptive feedforward, adjusting system stiffness and damping through fixed gain. It cannot dynamically constrain vibration errors to achieve flexible pullback, resulting in poor adaptability to sudden out-of-limit disturbances and disturbances of varying intensity and wide frequency band. This makes it difficult to balance control accuracy and stability, and it does not cover practical engineering constraints such as actuator saturation, which can easily lead to potential singularity problems in the control law.

[0005] Chinese patent CN105182801B proposes an active vibration isolation (PD) control method for the Stewart platform based on an extended state observer. This method has significant limitations: it can only effectively handle broadband sinusoidal interference and random noise, and is insufficiently adapted to sudden out-of-bounds disturbances; the convergence of the extended state observer depends on fixed error boundaries, and disturbances exceeding the threshold can easily lead to system instability; the error control lacks a dynamic constraint mechanism, making it unable to smoothly pull back out-of-bounds errors, and potentially introducing singularities.

[0006] Chinese patent CN108646758A relates to a multi-mobile robot pre-set performance formation controller structure and design method, used to enable follower robots to track the leader's reference trajectory and maintain time-varying formation, while constraining the error convergence range through a pre-set performance function. However, the pre-set performance function of this method is in the form of fixed exponential decay, which cannot flexibly adjust the boundary, cannot smoothly relax the boundary when the error exceeds the limit, lacks flexible adaptation capability, and is prone to singularity problems in the control law, resulting in insufficient stability and reliability.

[0007] Chinese patent CN113824361A relates to a fuzzy finite-time optimal synchronization control method for a fractional-order permanent magnet synchronous generator. By establishing a unidirectionally coupled fractional-order synchronization model, combined with a hierarchical type-II fuzzy neural network, a finite-time command filter, and a preset performance function, it achieves high-precision and rapid synchronization control between the active and driven generators, while suppressing chaotic oscillations and optimizing system performance. However, the preset performance function designed in this method lacks elastic boundary adjustment capability, thus failing to achieve smooth and flexible boundary adjustment when errors exceed limits, potentially leading to singular problems in the control law. Summary of the Invention

[0008] To address the problems in existing shipborne stabilization platform control technologies, such as fixed preset performance boundaries, inability to dynamically adjust performance, and spurious phenomena that easily occur when errors exceed limits or inputs become saturated, this invention provides an active wave compensation elastic preset performance control method for shipborne stabilization platforms. By designing an elastic performance function, introducing an alarm performance function and an activation threshold, the method achieves smooth relaxation of the boundaries.

[0009] To achieve the above objectives, the technical solution of the present invention is as follows: a method for controlling the active wave compensation elastic preset performance of a shipborne stabilization platform, wherein the dynamic equation of the shipborne stabilization platform is shown in equation (1):

[0010] (1) In the formula, For the actuator length vector, and These are the velocity vector and acceleration vector of the actuator, respectively. Here is the inertia matrix in joint space. The Coriolis / centrifugal force matrix in joint space. This represents the gravity vector in joint space. The position and attitude of the ship in the inertial frame. and These are the velocity vector and acceleration vector of the ship in the inertial frame, respectively. Let be the coupling mass matrix of the platform and ship motion in joint space. The Coriolis / centrifugal force matrix for the coupling motion of the platform and the ship in the joint space; It is the control input vector. It is the first The force generated by each actuator The aforementioned It is a positive definite symmetric matrix, and the matrix... It is obliquely symmetrical.

[0011] The aforementioned active wave compensation elastic preset performance control method for shipborne stabilization platforms includes the following steps: A. Design the elastic performance function A1. Define the regular performance function set up Let be the constant expected length vector of the actuator of the shipborne stabilization platform; define the actuator length error vector as . In order to achieve flexible preset performance control, the error The following performance constraints must be met: (2) In the formula, A performance function is preset for the lower bound elasticity. The upper bound elasticity preset performance function is designed as follows: (3) (4) In the formula, This represents the natural exponential function. and All are user-defined positive integers. For continuous time variables, This indicates the convergence rate.

[0012] A2. Design alarm performance functions The alarm performance function is designed as follows: Definition of the first The upper and lower alarm performance functions for the length error of each actuator are respectively and The expression is: (5) (6) In the formula, , It is a positive design constant.

[0013] A3. Design activation performance function The activation performance function is designed as follows: (7) (8) In the formula, , All of them are positive design constants.

[0014] A4. Design the elastic performance function The elastic performance function is designed as follows: (9) (10) In the formula:

[0015]

[0016] B. Design Error Transformation Function The error transformation function is designed as follows: (11) The derivative of the error transformation function with respect to time is given by the following formula: (12) In the formula: , .

[0017] C. Design of the active wave compensation elastic preset performance control law for the shipborne stabilization platform C1. Construct intermediate control vectors Define vector Find its derivative with respect to time, and apply equation (12) and ,have to: (13) In the formula, , .

[0018] Will Considering the virtual control input of equation (13), an intermediate control vector is constructed. Its expression is: (14) In the formula, It is a positive definite design matrix.

[0019] C2. Design of elastic preset performance dynamic control law The new error vector is defined as follows: (15) right The derivative with respect to time is given by the following formula: (16) The Lyapunov candidate functions are designed as follows: (17) right Find the derivative with respect to time by combining equations (1) and (13)-(16), and the matrix. Based on the property of antisymmetric matrices, we have:

[0020] (18) The pre-set performance control law for active wave compensation elasticity of the shipborne stabilization platform is designed as follows: (19) In the formula, It is a positive definite design matrix.

[0021] Substituting equation (19) into equation (18), we get: (20) Compared with the prior art, the present invention has the following beneficial effects: 1. This invention designs an active wave compensation elastic preset performance control law for a shipborne stabilization platform, which enables the closed-loop control system to asymptotically stabilize and ensures that the tracking error always meets the preset control performance constraints, thus significantly improving control accuracy.

[0022] 2. By designing an elastic performance function, this invention achieves smooth relaxation and flexible pullback of the boundary when the error exceeds the limit, thus avoiding potential singularity problems.

[0023] 3. Compared with existing solutions that require the introduction of auxiliary dynamic systems to handle constrained or saturated problems, the method of this invention relies only on algebraic operations and does not require the introduction of dynamic systems. This not only makes it simpler and more convenient to implement in engineering applications, but also allows for immediate response to these factors without delay. Attached Figure Description

[0024] Figure 1 Schematic diagram of the active wave compensation elastic preset performance control method for shipborne stabilization platforms. Detailed Implementation

[0025] The present invention will now be further described with reference to the accompanying drawings.

[0026] The specific implementation process of this invention is as follows: First, the actual length of the platform actuator is measured in real time. and with expected length The comparison yields the actuator length tracking error. Then, the system proceeds to the elastic performance function generation stage: the system will... Compared with the preset normal performance boundary and and stricter alarm performance boundaries and Perform real-time comparison, if If the alarm boundary is reached or exceeded, the activation performance function will be triggered immediately. and The final elastic performance function is generated by dynamically fusing the smoothing function. and This allows for flexible adjustment of the boundary; then, an error transformation function is used to adjust the boundary constrained by the elastic boundary. Mapping to unconstrained variables Based on this, we proceed to the design of the backstepping controller: first, construct a virtual control law, and then generate an intermediate control vector. Redefining speed error And in conjunction with the platform's dynamic equations, the final dynamic control law, i.e., the control torque, is designed. The control torque The actuators are applied to the platform and act on the platform's dynamic system to actively compensate for disturbances from the ship's motion, thereby forming a closed-loop control.

[0027] This invention is not limited to this embodiment. Any equivalent concept or modification within the technical scope disclosed in this invention shall be included within the protection scope of this invention.

Claims

1. A method for controlling the active wave compensation elastic preset performance of a shipborne stabilization platform, characterized in that: The dynamic equation of the shipborne stabilization platform is shown in equation (1): (1) In the formula, For the actuator length vector, and These are the velocity vector and acceleration vector of the actuator, respectively. Here is the inertia matrix in joint space. The Coriolis / centrifugal force matrix in joint space. This represents the gravity vector in joint space. The position and attitude of the ship in the inertial frame. and These are the velocity vector and acceleration vector of the ship in the inertial frame, respectively. Let be the coupling mass matrix of the platform and ship motion in joint space. The Coriolis / centrifugal force matrix for the coupling motion of the platform and the ship in the joint space; It is the control input vector. It is the first The force generated by each actuator The aforementioned It is a positive definite symmetric matrix, and the matrix... It is obliquely symmetrical; The aforementioned active wave compensation elastic preset performance control method for shipborne stabilization platforms includes the following steps: A. Design the elastic performance function A1. Define the regular performance function set up Let be the constant expected length vector of the actuator of the shipborne stabilization platform; define the actuator length error vector as . In order to achieve flexible preset performance control, the error The following performance constraints must be met: (2) In the formula, A performance function is preset for the lower bound elasticity. The upper bound elasticity preset performance function is designed as follows: (3) (4) In the formula, This represents the natural exponential function. and All are user-defined positive integers. For continuous time variables, Indicates the convergence rate; A2. Design alarm performance functions The alarm performance function is designed as follows: Definition of the first The upper and lower alarm performance functions for the length error of each actuator are respectively and The expression is: (5) (6) In the formula, , It is a positive design constant; A3. Design activation performance function The activation performance function is designed as follows: (7) (8) In the formula, , All are positive design constants; A4. Design the elastic performance function The elastic performance function is designed as follows: (9) (10) In the formula: B. Design Error Transformation Function The error transformation function is designed as follows: (11) The derivative of the error transformation function with respect to time is given by the following formula: (12) In the formula: , ; C. Design of the active wave compensation elastic preset performance control law for the shipborne stabilization platform C1. Construct intermediate control vectors Define vector Find its derivative with respect to time, and apply equation (12) and ,have to: (13) In the formula, , ; Will Considering the virtual control input of equation (13), an intermediate control vector is constructed. Its expression is: (14) In the formula, It is a positive definite design matrix; C2. Design of elastic preset performance dynamic control law The new error vector is defined as follows: (15) right The derivative with respect to time is given by the following formula: (16) The Lyapunov candidate functions are designed as follows: (17) right Find the derivative with respect to time by combining equations (1) and (13)-(16), and the matrix. Based on the property of antisymmetric matrices, we have: (18) The pre-set performance control law for active wave compensation elasticity of the shipborne stabilization platform is designed as follows: (19) In the formula, It is a positive definite design matrix; Substituting equation (19) into equation (18), we get: (20)。

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