STATISTICAL REDUCTION TECHNIQUE FOR ZERO POSITION ERROR BETWEEN SENSORS IN IMPROVED SEQUENTIAL THREE-POINT METHOD

摘要

Demands are increasing for highly-precise surface shape measurement of large curved surface such as lens and reflecting mirror for telescope. However, there is no useful method for the purpose because of inevitable difficulties in preparing large tangible datum and to avoid the influence of error motions in measuring operation. On the other hand, the sequential three-point method, which does not require the tangible datum, is well known as a useful technique for on-machine straightness measurement of large parts [1]. However, if a zero position error between sensors exists, a large quadratic error component is superimposed on measured shape profile.