The study of stabilisation performance is a crucial consideration in the design of offshore floating platforms. For large floating structures, incorporating passive anti-roll tanks is a common technique for roll reduction. To investigate the feasibility of using ballast tanks for roll attenuation on the "Guo Hai Shi 1" platform, this study employs the internal tank theory to analyze the influence of four independent empty tanks, located around the platform, acting as anti-roll tanks with varying ballast water volumes. The results indicate that: (1) Different ballast water volumes within a single tank do not significantly affect the static stability parameters of the platform. (2) In regular wave simulations, the ballast tanks show limited effectiveness in reducing pitch motion along the wave incidence direction but effectively suppress coupled responses in other degrees of freedom. In the resonance case (Case 3), the minimum pitch occurs in Condition 1 at 10.56°, while the maximum pitch reaches 11.45° in Condition 2. Nevertheless, a 40% reduction in roll motion is achieved (3.36° in Condition 4 vs. 5.60° in Condition 1), along with a 24.5% reduction in yaw motion (39.22° in Condition 4 vs. 51.94° in Condition 1). (3) In irregular wave simulations, the ballast tanks effectively reduce the heave amplitude by up to 8.34% in sea state level 4 and 6.06% in sea state level 8, thereby enhancing its wave-following performance in the heave degree of freedom. (4) A CNN_BiLSTM_Attention algorithm is developed using hydrodynamic analysis generated datasets to predict the pitch motion time series of the platform under different ballast water conditions and sea states, while the model has a superior prediction performance (R² = 0.9658, RMSE = 0.5343, MAE = 0.3188, representing a 4.82% increase in R² and 30.31% reduction in RMSE compared to the original model). Future work will further explore the application of ballast tanks on floating platforms, with a focus on performance optimization and the development of advanced neural network models capable of predicting motion responses under various ballast configurations. Moreover, appropriate evaluation metrics will be established to assess the effectiveness of ballast tank designs. Efforts will also be directed towards integrating time-domain motion prediction using neural networks with control theories aimed at dynamically regulating ballast water volume to enhance platform stability.

With China’s exploration of the sea, unmanned boats on the water are receiving more and more attention. Due to the complex situation on the water, unmanned boat obstacle avoidance still has defects. To address the above problems, this paper designs unmanned fish-finding and obstacle avoidance based on Pixhawk. The Kalman filter algorithm is used for sensor information fusion, which realizes the state estimation of the fish-finding unmanned ship. The BUG2 obstacle avoidance algorithm is used for obstacle avoidance, that optimizes the automatic obstacle avoidance function of the fish-finding unmanned ship. The fish finder is used to detect the position information of the fish, that realizes the function of the fish-finding unmanned ship tracking the fish. The PID control algorithm is used to control the driving of the ship, which makes the fish-finding unmanned ship converge to the desired course quickly and accurately. The lateral error of the vessel is within 1m. The simulation results verify the feasibility of the system, and the sea trial experiments of the unmanned fish-finding vessel prove the reliability and stability of the system.

The Pointing Acquisition Tracking (PAT) technology, as a powerful guarantee for fast establishment and stable communication of wireless laser communication links, is the key to improve the practicality of shipboard wireless laser communication. In this paper, the initial pointing method of the shipboard laser communication terminal is designed by using the position and attitude information obtained from the GPS/INS module. Since the system optical relationship varies with the coarse tracking mechanism attitude during tracking, the optical decoupling model from the coarse tracking mechanism to the CMOS detector is measured using the optical matrix method. On this basis, the robust linear active disturbance rejection control (LADRC) algorithm is used for spot tracking. Designing the acquisition and tracking experiment of maritime laser communication, using the initial pointing algorithm to obtain the initial pointing angle of the antenna boresight and successfully capture the beacon light. Experiments show that the tracking peak error of coarse tracking is around 40urad, and the standard deviation is below 20urad. the tracking peak error of fine tracking is around 15urad, and the standard deviation is below 10urad. The experimental data show that the tracking algorithm meets the requirements of stable, reliable and high-precision tracking.