Complex Workpiece Barycenter Evaluation And Correction Based On Sphere Error Theory

In the manufacturing process of machinery and equipment, due to the non-design factors of material defects, processing error and assembly error, the workpiece barycenter of the actual position and theoretical position will be inconsistent, which will have a negative impact on the performance of the workpiece. So when the actual barycenter position has been measured, it is necessary to evaluate and correct it in a certain way to move the barycenter to the appropriate location.According to the distribution characteristics of the barycenter point data, it proposes the concepts of the minimum enclosing ball and the tolerance ball based on the mathematical theory closure domain. In the respect of conceptual nature and optimization search respectively, it put forwards four algorithms to solve the minimum enclosing ball and the tolerance ball in low dimension. Make the numerical test of the algorithms by Matlab and then give the algorithm analysis and evaluation according to the results of numerical test.Through the comparison of relative position between the minimum enclosing ball and the tolerance ball, it proposes the data point error determination criterion. Aiming at the optimization data correction request, it proposes corresponding data error correction scheme by the standard of the shortest correction distance and the minimum modified discrete degree respectively. Descript and evaluate the data error processing mode based on the distribution of Statistics.Evaluate and correct the workpiece barycenter by the data error processing mode proposed. Different workpiece has different means of barycenter correction, so it corrects the barycenter of single workpiece and assembly respectively by different correction methods. Calculate the corresponding relationship between the correction position and the correction amount according to the principle of barycenter moment balance, so as to give the corresponding barycenter evaluation and correction scheme.Taking marine combination propeller as subject investigated, it proposes the correction scheme to give the example verification. According to the characteristics of marine combination propeller structure and the way of using, it gives the most reasonable correction scheme. Then verify the mechanical properties of the propeller before and after correction respectively. The result shows that the correction scheme can improve the mechanical performance of the propeller.In order to facilitate the practical application, it develops a set of applications plug-in based on UG/Open aiming at the problem of barycenter evaluation and correction. The previous theory and method will be integrated in the application. It also gives the main design method of the application and detailed operation steps, which will guide the evaluation and correction of the workpiece barycenter.