Precision reliability analysis method for heavy numerical control machine tool

The invention belongs to the field of reliabilities of numerical control machine tools, and particularly relates to a precision reliability analysis method for a heavy numerical control machine tool based on a multi-body system kinemics theory. The precision reliability analysis method comprises the following steps: constructing a relation model between the output precision error of the heavy numerical control machine tool and a factor affecting the precision of the machine tool, fitting a change relation of the factor affecting the precision of the machine tool along with the time by a random process, finally combining on-site data or data of the same type of sample, and introducing a Bayes evaluation method to update the precision error model of the heavy numerical control machine tool, thus realizing evaluation of the precision reliability of the machine tool. The precision reliability analysis method has the beneficial effects that the Bayes evaluation method is introduced to fit and correct the change tendency of respective factors causing a motion precision error of the machine tool, so that the difficulty that a sufficient statistical sample cannot be formed due to a 'small sample' is solved; and therefore, more scientific and reasonable evaluation is performed on the dynamic reliability of the precision error of the heavy numerical control machine tool.