Matching of drill-pipe thread with reference profile

The most known methods focusing on matching problems consider counters, which are described by just one equation that limits their application for real object profiles. This work presents derivation of algorithm for matching of drill-pipe thread with reference profile and simulation results concerning on accuracy estimation of matching parameters. This problem appears during evaluation of drill-pipe depreciation parameters including thread connection. Proposed algorithm is based on straight-line equations, describing straight-line segments of thread connection, and assembly of points at plane being obtained by profile scanner during measurement of drill-pipe thread. It connects straight-line equations and coordinates of points, that is described by by transform matrix (offset and rotation matrix). Solution is led to system of nonlinear equations, which is solved by iteration method. During simulation, we researched impact of Gaussian noise to accuracy of matching parameter estimation. Results of measurement are also represented. Approbation of proposed algorithm was realized on real object profile.