PROFILE CONTROL DEVICE WITH CORRECTING FUNCTION FOR SPHERICITY OF STYLUS

PURPOSE:To obtain a correct value by finding a measuring stylus displacement and mechanical displacement by profiling a model whose shape is not distinct by the measuring stylus and adding the stored difference corresponding to the vector based on the measuring stylus displacement to this value. CONSTITUTION:A mechanical position is detected by a mechanical position detecting part 21, the displacement signal is input to a displacement detection part 22 from a tracer head 1 and the displacement of the position of a stylus is measured. Then, the contact point coordinate for the model of the stylus is found by composing the displacement from the displacing direction of the stylus by a vector arithmetic part 27 and a sphericity correction value is found by using the coordinate of the contact point found by the vector arithmetic part 27 and the error of the sphericity of the stylus stored in a memory part 31 by a sphericity correction arithmetic part 32. In a measuring position arithmetic part 23 three of the mechanical coordinate found by the mechanical position detecting part 21, the stylus displacement found by the displacement detection part 22 and the sphericity correction value found by the sphericity correction arithmetic part 32 are composed and a correct coordinate of the stylus is found.