초록 ▼

A nominally cylindrical surface of a workpiece is sensed by a stylus displaceable radially of an axis of rotation of the surface relative to a support column defining a reference datum so that the stylus follows the cylindrical surface at a given height along the surface. Relative rotation of the wo

A nominally cylindrical surface of a workpiece is sensed by a stylus displaceable radially of an axis of rotation of the surface relative to a support column defining a reference datum so that the stylus follows the cylindrical surface at a given height along the surface. Relative rotation of the workpiece and the stylus about the axis of rotation of the surface is effected and the displacement of the stylus used to determine information relating to the radial form of the surface at that height. These measurements are represented at different heights along the surface so as to determine its cylindrical form. The displacement of the stylus from a given position on the surface at each height before and after rotation of the stylus and workpiece through 180.degree. are measured and the resulting measurements used to compensate for any error or deviation in the reference datum.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method of determining information relating to the form of a surface of an object such as a workpiece, which method comprises sensing the surface using sensing means displaceable relative to a reference datum so as to follow the surface, effecting relative rotation abo

[ What is claimed is:] [1.]1. A method of determining information relating to the form of a surface of an object such as a workpiece, which method comprises sensing the surface using sensing means displaceable relative to a reference datum so as to follow the surface, effecting relative rotation about a rotation axis between the surface and the sensing means and using measurements made by the sensing means as the sensing means follows the surface during the relative rotation to determine information relating to the form of the surface, which method further comprises causing the sensing means to make a measurement at each of at least two positions equiangularly spaced apart around the axis of rotation so that the direction relative to the reference datum from which the sensing means senses the surface differs from each of the at least two positions and combining the measurements to compensate for error or deviation in the reference datum.