Abstract: Parallel kinematics machine (PKM) has a relatively complicated structure which contains many kinematical pairs, how to realize its error analysis is currently a problem of PKM. Based on the 3-TPS PKM with constraint mechanism, the pose error models of parallel mechanism and constraint mechanism are separately established. The pose error caused by single geometrical error source is calculated. By using Monte-Carlo method, the statistic effect of geometrical error sources in either mechanism is analyzed. The analysis indicates that the geometrical error sources in constraint mechanism affect more on the pose of machine tool end.

Key words: Constraint mechanism, Hybrid parallel mechanism, Pose error