Research On Relative Dynamic Positioning Method Between Rescue Vessel And Wreck Vessel

With the expanding scales of ocean exploitation and ocean transport, a large number of vessels sail on the vast ocean every day. Following these vessels and accidents continue to increase, which made the maritime rescue more new requirements. Maritime Rescue is an important method to save lives and protect property during the accidents. In the complex and variety marine environment, when the vessels float freely on the ocean due to power system failures, the relative position between the rescue vessel and wreck vessel must be brought, also the rescue vessel headings. Therefore, the appropriate DP method is the key to successful rescue. This paper concerned with the 8000kw rescue vessel project needs, give a research method to relative dynamic positioning between rescue vessel and wreck vessel. This paper includes the following sections:First of all, based on the MMG Separate modeling ideas, this paper constructed the 3-DOF kinematics models of rescue vessel and wreck vessel, and also the models of wind, wave, current.Then, for measuring the changing relative distance and heading errors of them, this paper combined with the laser characteristics,laser rangefinder principle presents the method to calculate the distance and the headings between them, using existing laser rangefinder validates the accuracy and feasibility of the method. Meanwhile, this paper gave a fast algorithm of median filtering method to deal with the data noise, and also gave the math model of the laser ranging.Last, for 3-DOF motion of the rescue vessel, this paper studied the tuning parameters based on fuzzy PID control algorithms. Fuzzy PID controller tunes the parameters on-line in response to the complex and variety marine environment disturbance, making the controlling and tracking performance of the relatively dynamic positioning validated by simulating the vessel models. Meanwhile, it proved the feasibility and efficiency of the method concerned in this paper.The method studied here has a great practical significance as it gives preconditions to ensure the maritime rescue safety and quickly provided.