A 3-PUU parallel mechanism was studied, which can perform one-dimensional translation about z-axis and two-dimensional rotations about y-axis and x-axis. This paper shows the study about the precision analysis, the dimensional analysis and the synthesis problem of the parallel mechanism having less degree of freedom. First, the closed-loop vector model was built based on analyzing the branched-chains of 3-PUU, the pose error model was built through the differential geometry, and the error model of positive solutions was obtained which contains all the structural parameters errors. For the error of structural parameters given, the pose output error can be solved out by application of this model, the area of maximum error is found out. And the influence of pose output error was analyzed with postures changed. The dimensional analysis of 3-PUU was also done by this error model, and the reasonable selection of mechanism parameters was discussed. And then the rationality of structure dimensional design was discussed in this paper. Finally, this method also may be used in the dimensional analysis of other less freedom parallel mechanisms.
Output Error Model Identification Against Unexpected Load Disturbance
