Aircraft Assembly Parallel Platform Design And Positioning Accuracy Research

With the rapid development of domestic civil aircraft manufacturing industry in recent years,the big parts assembly automation degree is higher and higher.The development and application of flexible assembly technology is the major trend of civil aviation manufacturing industry.In this paper,facing to the current civil aircraft need automated assembly of large size components,fuselage and docking,for example,6-PSS parallel experiment platform was designed,and analyze the geometric parameters of the manufacturing error,by assembling tolerance predict terminal positioning deviation;6-PSS parallel experiment platform for geometrical parameter calibration,forecast range calibration results,and through the calibration experiment validate the result of the forecast.The main contents of this paper are as follows:1、The structure of the 6-PSS parallel mechanism has been designed.The institutions and parameters of the fixed platform has been calculated.Optimized the length of screw and spherical pair corner constraints through the analysis of the mechanism singularity of the bar length.2、6-PSS parallel positioning error of the geometric linear model has been set up.The operating mechanism of the error transfer region mapping model has been put forward,and according to the characteristics of the linear error transfer model,advantages was analyzed,methods and application of the length error of 6-PSS in the presence of the accuracy of the analysis.3、The concept of the hypercube has been put forward for the measurement error of a measuring instrument,as a case study of the laser tracker measurement error are analyzed in detail the measuring point distribution and scope of the nearby.Based on the distribution of measurement error and measurement error-calibration residual relationship,analyses the calibration residual distribution and the relationship between the measurement error.Proposed can reduce calibration residual evaluation index,the error transfer matrix of the generalized inverse of infinite norm index.The smaller the index,after the calibration of the geometric parameters of residual distribution will be smaller.According to the proposed evaluation index,the algorithm selection has been done on the calibration configuration by the improved PSO.Numerical simulation has been done for the calibration configuration optimization and geometrical parameter calibration locator respectively.Results showed that after optimizing the evaluation index of much better than before optimization.And the results of numerical simulation calibration institutions also confirmed the effectiveness of the proposed indicators.4、6-PSS parallel positioning platform calibration experiment was carried out,measuring the 54 configuration to simulate a set of posture,anchor point at the end of the calibration after the absolute positioning accuracy can reach about 0.33 mm,meet the requirement on the assembly of the simulator.For the 6 PSS parallel positioning platform docking experiment,the experimental results by docking feature points at the end of the docking deviation is 0.3421 mm,satisfies the requirement of docking.