| Large roller is the crucial component of manufacturing equipment.Its profile errors,including roundness,cylindricity and generatix straightness,will be directly copied to the produced products,causing surface flaws of the products.Therefore,cylindrical profile is an important factor in determining surface qualities of the products.How to improve the cylindrical profile measurement accuracy and avoid or reduce the influence of spindle rotary error motions and carriage straightness error motions during online measurement process has been a challenge.Relying on the National Natural Science Foundation of China,the dissertation focuses on studying the feasibility,regularity and applicable conditions of integrating singular value ratio analysis and multi-point error separation techniques to achieve cylindrical profile measurement and reconstruction.The aim is to explore a kind of cylindrical profile precision measurement technology by using minimum number of sensors to reduce interferences in measurement process and improve measurement accuracy.The main research work of this paper is as follows:1.The basic theories of signal separation based on singular value ratio analysis,including singular value ratio structure,singular value decomposition and reconstruction of signal were expounded.Based on simulation,the basic rules of identifying signal period by singular value ratio analysis and achieving signals' decomposing and reconstructing were explored.2.A decomposable condition according to the periodic relationship of the radial error motion signal and cross-sectional profile signal is studied by simulating single-sensor single-section multi-circle measurement process and analyzing singular value ratio spectrum.It was verified that the singular rate spectrum method cannot avoid harmonic suppression,and when the periods of cross-sectional profile signal and radial error motion signal have a common number P,the "section profile period/P" order harmonic suppression will occur.3.The two-point singular value ratio spectrum error separation method is proposed.It was known that the two-point error separation method can accurately separate the even-order harmonics of cross-section profile except odd-number harmonics.When the singular value rate spectrum method has only even-order harmonic suppression,it wasproved by the theory and simulation that combining the singular value rate spectrum method with the two-point error separation method can realize the full harmonic error separation of cylindrical profile measurement.4.A three-point singular value rate spectrum error separation method is proposed.When the periods of radial error motion signal and cross-sectional profile signal is not integer multiple,the singular value rate spectrum method can accurately measure the first harmonic of cross-sectional profile,which makes it possible to accurately measuring the medium line deviations of the cylindrical profile.Meanwhile,the three-point error separation method can accurately measure all the order harmonics except the first order,which means that accurate measurement of the radius deviations and cross-section deviations of cross-sectional profile may be realized.When the periods of the two signals are not integer multiple,it was proved by the theory and simulation that integration singular value rate spectrum method with the three-point error separation method can realize the full harmonic error separation in the precise measurement of cylindrical profile.5.Through the existing instruments and equipment,based on repeated experiments,it was verified that the three-point singularity spectrum error separation method can accurately measure the medium line deviations of the cylindrical profile,radius deviation and roundness deviation,and measured and reconstructed cylindrical profile conforms to the definition of ISO 12180.6.Some valuable theoretical and simulating studies are demonstrated in the dissertation.The feasible conditions and related conclusions of singular value ratio spectrum technique in the cylindrical profile measurement are of certain reference significance for precision online cylindrical profile measurement and reconstruction. |
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