Abstract
A modified triangular laser displacement sensor having a resolution of was used to measure the diameter of a turned workpiece with curvatures. This sensor was attached to a specially designed stage mounted on a precision slide unit and operated by three drive motors. In the measurement, the laser sensor was controlled by a motor depending on workpiece curvatures so that the illuminating laser beam is always normal to the part surface and can measure the workpiece diameter in an on-line fashion. This sensor positioning control was found to be effective for measuring the diameter of a curved workpiece with an accuracy of several micrometers.