Research On Installating&Positioning Method And Working Space For Intermediate Shaft In Ship Propulsion Shaft System Based On Motion Mechanism

The efficiency and accuracy of the ship propulsion shafting alignment are related to the ship’s construction period and quality.For the traditional installation methods,depending on the environmental conditions and the engineering experience of the construction personnel,in which there are problems of long cycle,poor precision and low efficiency,a smart bracket system for space high precision assembly was designed to improve the automation of the shafting installation.The intelligent bracket system designed for the adjustment of the position and attitude of the shaft segment is explained in detail,and the composition of the moving mechanism and the functions of each part are summarized.Based on the working principle of the adjustment,the motion mechanism is used to realize the position of the shaft segment through the cooperation of the linear guide and the electric cylinder.Then the control system of the intelligent support system was expounded,and the test bench for the automatic installation of the ship propulsion shafting was built in the laboratory based on the designed intelligent support system.Based on the designed motion mechanism,firstly,referring to the traditional single unknown node positioning method,the sensor observation model of the arbitrary pose of the shaft segment is established.And the trilateral centroid localization algorithm is used to design a three-dimensional wireless sensor network based on multiple known beacon nodes for the actual situation of the spatial position and attitude of the shaft segment,to achieve precise positioning of the position and attitude of the shaft segment.Then,the main factors affecting the contour and size of the working space of the moving mechanism are explained.The boundary curve is analyzed and compared by graphical method and numerical method,and the Monte Carlo method is used to solve the three-dimensional map and the cross-sectional view of the working space of the moving mechanism.Comparing with the theoretical solution,it is found that the Monte Carlo method has error less than 1% in calculation results and theoretical solution,which achieves high accuracy.Finally,the measurement method of the median value of the adjacent flange on the ship propulsion shafting are analyzed,the traditional measurement methods such as ruler and thickness gauge measurement,dial gauge measurement method is summarized,and LD-PSD based bias is applied to the ship propulsion shafting,including single LD-PSD measurement and dual LD-PSD measurement.Finally,the mathematical model of the midline measurement of the shafting is analyzed,taking the single LD-PSD measurement as an example.The research work on positioning method,working space and partial median measurement in the paper makes the position adjustment process of the intermediate shaft controllable and efficient,and high-precision and automated ship propulsion shafting installation is achieved,which can be used as the basis of research on theory and technology intelligent installation of the ship propulsion shafting system.