A Preliminary Study On The Comprehensive Optimization Of A Pentamaran Unmanned Boat

As an intelligent water vehicle with the advantages of low operating costs,high operational efficiency,flexibility and the ability to replace humans in high-risk environments,the surface unmanned boat has been gradually gaining attention and has been widely used in marine survey,maritime patrol and water quality monitoring tasks,with good development prospects and a broad market space.This thesis takes a slender pentamaran unmanned boat as the research object,establishes a mathematical model for the comprehensive optimisation of the pentamaran unmanned boat based on multidisciplinary design optimisation and ship performance theory,and carries out a boat optimisation analysis for the designed boat.The specific work and results of this thesis are described as follows:(1)The fuzzy comprehensive evaluation method was used to analyse the boat type selection of the designed unmanned boat,and a preliminary design analysis was carried out from various aspects such as its usage,navigation area and boat performance.On this basis,the main side hull type of the pentamaran unmanned boat was selected and the preliminary design of the side hull layout was carried out.At the same time,a response surface fitting method was used to fit various parameters such as the residual drag coefficient and static displacement of the boat,and a database of boat types and drag was constructed.(2)Based on the theory of multidisciplinary design optimisation,a comprehensive mathematical model for the optimisation of the four major navigation properties(speed,manoeuvrability,wave resistance and stability)of the pentamaran unmanned boat was established,including the selection of the objective function,the establishment of the constraints and the selection of the design variables and their upper and lower limits.(3)Based on the study and analysis of genetic algorithm,chaotic algorithm,particle swarm algorithm and two improvement strategies,the relevant optimisation calculation software is improved by combining the established comprehensive performance optimisation mathematical model;the best optimisation calculation scheme is determined by comparing and analysing the best calculation results of the above-mentioned optimisation algorithms,and the best boat-type parameters are finally obtained.(4)A detailed design of the manoeuvring system and intelligent navigation system of the pentamaran unmanned boat was carried out,in which the manoeuvring system includes the selection of propeller,rudder,shaft system and main engine,and the intelligent navigation system includes the design of the main control system,navigation and positioning system,PID attitude correction system and collision avoidance system.On this basis,an intermediate test boat was made by combining the optimized boat parameters.(5)A mathematical model for system identification of the speed,manoeuvrability and wave resistance of the pentamaran unmanned boat was established,the input and output quantities of the mathematical model were determined,and a test data acquisition system was developed accordingly.(6)A test programme was developed for each of the five hulled unmanned boats and relevant tests were carried out.In the speed and manoeuvrability tests,the test data obtained were imported into the system identification software for identification calculations,and then the identification parameters calculated by the identification software were verified and analysed,and the results proved the rationality of the system identification mathematical model and the reliability of the developed test system and system identification software.In the wave resistance and intelligent navigation tests,the test results were processed and analysed accordingly,and the good wave resistance and reliable intelligent navigation system of the pentamaran unmanned boat were verified.Through the work of this thesis,the overall design of the pentamaran unmanned boat and the production of the boat model have been realised,and the relevant data analysis has been carried out,laying a good technical foundation for the further development of other functions and providing a theoretical basis for further in-depth research,which is also of great significance for the improvement of the development level of the pentamaran unmanned boat.