Research On Probe Radius Compensation Of On 5-axis Machine Measuring System

Parts with complex surface are widely used in aerospace, shipbuilding, automobile industry, but its processing and measurement are high costs, and the quality of processing is difficult to guarantee. The on machine measurement is a main research directions of parts measurement and has obvious advantages compared with the traditional measurement methods. Thus, the research on 5-axis machine measurement system can realize the integration of the processing and the measurement of complex surface parts. It has important theoretical and practical significance of guaranteeing the quality of processing.This article, aiming at the problem of low precision and low efficiency of the probe radius compensation, proposes the method of probe radius compensation based on triangular mesh model, and the method of probe radius compensation based on triangle mesh and surface reconstruction. The main research contents are as follows:(1)Described in detail the composition and working principle of the on 5-axis machine measurement system, summarized and classified source of error of the on machine measurement. Analyzed the influence of error sources and laid the theoretical foundation to reduce measurement error.(2) Proposed the method of probe radius compensation based on triangular mesh model. First, divide the sampling points into triangular mesh with the Delaunay method. Second, calculate the normal vector of each triangle, compute weighted average normal vectors with the same vertex. Last, use the weighted average normal vectors to compensate sample point data. Through an example, proved that the method has very high compensation precision when surface with small curvature and large angle between surface normal vector with xoy plane.(3) By analyzing the radius compensation method based on triangular mesh model, we discovered the method has larger error when the surface curvature is larger or the angle between the surface normal vector and the xoy surface is smaller. We proposed the method of probe radius compensation based on triangle mesh and surface reconstruction. First, classify the sampling points. Second, reconstruct B spline surface on sampling point set with larger surface curvature or smaller angle between the surface normal vector and the xoy surface, use the normal vector of the reconstructed surface to compensate correspondent sample point data. Third, use the method of probe radius compensation based on triangular mesh model to compensate the sample point set with smaller surface curvature or larger angle between the surface normal vector and the xoy surface. At present, we complete the probe radius compensation of all sample points. Finally, through simulation experiments, it is proved that this method improves the precision of probe radius compensation.