Large cylindrical workpiece dimension and geometric error measurement method

The invention provides a large cylindrical workpiece dimension and geometric error measurement method. An indirect measurement method is adopted to obtain the feature points of the measured elements of a workpiece; a homogeneous coordinate transformation method is adopted to transform the obtained feature points into a measurement coordinate system together by way of coordinate translation; a least square feature fitting algorithm is adopted to structure the fitted elements of the measured elements from the feature points, and the workpiece dimension and the geometric error are measured. The invention designs a method for correlating a measurement instrument and detection toolings with sensor data, the measurement instrument and targets are formed into the measurement coordinate system, and an auxiliary coordinate system is arranged on the detection toolings. The measurement method is highly universal; by utilizing a conventional measurement system, the measurement method not only canbe used for measuring the geometric elements of cylindrical workpieces, but also can arrange a plurality of sets of detection toolings at different positions according to different measured workpieces; and by changing the shapes of the detection toolings, a measurement device can be used for measuring other large rotary workpieces.