Research On Motion Characteristics And Parameter Optimization Of Ship Simulation Platform

The six-degree-of-freedom ship simulation platform is a typical motion simulation platform with rapid development and wide application.It can simulate the composite motion of six degrees of freedom of sway,turbulence,heave,roll,pitch and sway generated by a physical ship under complex sea conditions.It has been widely used in ship equipment simulation research and seafarer training to reduce the number of sea trials on the ship and enhance the adaptability and professional quality of maritime search and rescue personnel.Therefore,a six-degree-of-freedom ship simulation platform with excellent design performance is very important.In order to design a six-degree-of-freedom ship motion simulation platform with excellent performance,it is necessary to analyze its kinematics characteristics,and then use the optimization algorithm to obtain the optimal structural parameters.According to this idea,this paper mainly studied the following points:First,established the structural model of the platform,derived the mathematical model of kinematics,and solved the unique kinematics positive solution.According to the actual structure of the platform,this paper first established the structural model of the platform.Under the influence of the Hook hinge,the complete kinematics mathematical model was derived.Finally,the variable search initial value iterative method was used to solve the unique real kinematics positive solution.The follow-up research platform lays the foundation for the control strategy based on the positive kinematics solution.Second,the analysis platform produces two singular situations and performs detection and optimization.The spiral theory analysis was used to find the two situations in which the platform produces singularity,which are kinematic singularity and constrained singularity.In order to quickly detect whether the platform has singularity,the nonlinear programming genetic algorithm was proposed to search and optimize the platform.The comparison proves the effectiveness of the proposed detection algorithm.Thirdly,the error modeling was carried out to simulate the platform pose;considering the source of each error of the platform,the error modeling of the platform was carried out by vector differentiation method and DH matrix methodrespectively;the maximum pose error model of the platform was derived based on DH matrix method.On this basis,the specific examples were simulated and analyzed,and the influence of the translation and rotation of the upper platform on the maximum error of the platform pose was studied.Fourth,the multi-objective parameters were optimized for the platform based on the motion characteristics and accuracy.Aimed at the problem that the designed platform needs to meet the motion characteristics and accuracy requirements,the Jacques matrix condition number and the maximum pose error were used as the performance indicators to establish the objective function.Then the improved adaptive non-dominated sorting genetic algorithm was used to optimize the parameters of the platform.The optimal parameters are superior to the traditional multi-objective genetic algorithm in terms of distribution and diversity.Finally,the singular detection algorithm was used to detect the effectiveness and feasibility of the proposed optimization algorithm.By studying the motion characteristics of the platform,the platform structure parameters with excellent performance will be obtained after optimization design,which provides a feasible method for the optimization of the six-degree-of-freedom ship simulation platform in engineering design.