Research On The Key Technologies Of Marine Propeller Blade Measurement

Propeller blade measurement is an essential process in the production of propellers and the measurement outcome is critical to the accuracy of the propeller manufacture and impacts on the overall working.Marine propeller blades are complex in profile and contain a multitude of complex surface shapes.The current methods suffer from low point description capability,time-consuming data collection and large quality assessment deviation.The method is difficult to combine high measurement efficiency and measurement accuracy at the same time.In view of the inadequacies of current propeller blade measurement methods,in this thesis,based on a comprehensive analysis of the actual needs of enterprises,blade geometry characteristics and existing measurement technology,the core measurement technologies such as measurement point planning,data acquisition and quality assessment are used as entry points to carry out further research on the key technologies of marine propeller blade measurement.Includes the research of measurement deviation analysis and compensation technology on the data acquisition part,the research of propeller blade type complex surface measurement point planning method,the research of propeller blade measurement quality assessment method,the research of mechatronic simulation design of measurement device and the research of system software development technology.The details of the research are as follows:(1)In order to secure the high accuracy acquisition of the core measurement component,the laser measurement sensor,and research on the factors influencing the accuracy of laser measurement is carried out.Combining the hardware part with the measurement distance and angle of incidence,a single-factor deviation effect measurement experiment is carried out,analysis the deviation distribution and properties and establishing the deviation compensation curve.(2)In view of the existence of multiple complex surface concentrations on the surface of propeller blade type parts,an adaptive planning method of measurement points for differential measurement regions is proposed.The main steps include: constructing an improved CVT model with a bi-extremes selection seed point extraction model under a smoothness index,extracting the selection seed point and guiding the selection of the initial segmentation region.Combining seed point sets for feature tensor-driven surface energy clustering segmentation to segment measurement regions and enhance the regional description of measurement points.Adaptive surface deviation measurement point generation under the feature stacking axis is performed based on the region segmentation.The final experiment proved that the method effectively optimises the descriptive power of the measurement points while improving the efficiency of the measurements.(3)In view of the complex profile of propeller blades and the differences in accuracy requirements between measurement regions,a new propeller blade measurement quality assessment method is proposed in conjunction with alignment techniques.First,filtering of deviating interference points,and the marker points optimization Super-4-pints congruent sets algorithm combined with a fast point histogram is proposed to provide the initial positional values alignment for precise alignment.Then,considering the difference in regional accuracy,the alignment problem model and the model solving method,a non-linear difference hierarchical point-plane precision alignment method is proposed to achieve high accuracy positional alignment between measured and theoretical data,providing a basis for evaluation.Finally,with reference to the propeller design requirements,the experimental verification of the method for fast and accurate deviation evaluation and visualisation of the residuals.(4)To carry out feasibility verification of measurement structures and technical methods based on synergistic mechatronics technology.First,the functional requirements and logical movements are analysed using the MCD platform and the modules are given electromechanical properties.Then,the logic program and the execution configuration are prepared on the TIA Portal side,and the signals are interacted with on the PLCSIM side to create a simulation and debugging environment in conjunction with MCD-PLCSIM-TIA Portal.Finally,the feasibility of the measurement structure and the versatility of each technical method for propeller blade measurement are verified through simulation experiments,and the software development of the measurement system is completed.