Research On Geometric Error Modeling And Compensation For Propeller Laser Measuring Machine

Marine propeller is one of the important parts of the ship power system, its quality and performance will have an enormous impact on the dynamic performance and stability of the ship directly. The measurement of Propeller rough is a prerequisite for manufacturing and processing. The traditional manual measurement is low efficiency and accuracy. A large propeller laser measuring machine can solve the drawbacks of traditional measurement to achieve high efficiency and precision measurement requirements. But due to manufacturing errors and assembly errors do not meet the requirements, the propeller laser measuring machine produce measuring machine geometry errors. The geometric error components more complex form because of multi-axis and large travel. These geometric errors have great impact on propeller laser measuring machine accuracy after each movement of the shaft coupling amplified.In order to solve the complexity of propeller laser measuring machine geometric error, the structure of the measuring machine is specifically analyzed. Geometric errors are separated into assembly error associated with meauring machine assembly precision and motion geometric errors associated with the position change. Measuring Machine components topologies are described in abstract based on the theory of multi-body system. The local coordinate system is established used to express the amount of error for each coupling relationship between the components and deduce the expression of the ideal position and the actual position of CMM probe. Finally measuring machine space geometric error model is established.The sensitivity analysis method of measuring machine geometric error is proposed. By comparison of the size of the normal error values between laser probe measuring point fit surface after a motion to conside an error component and propeller design model surface,the impact on the error component of measurement error for each motion axis is obtained. Preparations were calibrated based on laser tracker. The geometric error measuring machine calibration experiment is completed according to the calibration program.The process of solving the error measuring machine assembly structure and movement of geometric error are described. Date points measuring by laser tracker are used to fit each linear axis. The verticality between the axes and between the shaft and the planes is solved.Solving the displacement errors and angular errors of each shaft is finished.Based on the machine geometric errors which have been solved and combined with spatial geometric error model of measuring machine, the values of spatial geometric error are solved. The compensation method of space geometric error is proposed. To achieve the purpose of error compensation through multiple iterations and correcting the NC command. Finally, the simulation error compensation is completed.