Accuracy analysis of the serial-parallel micromotion manipulator

The 6 DOF serial-parallel micromotion manipulator discussed in this paper comprises two 3 DOF parallel mechanisms connected in series with one another. Manufacturing tolerances, actuation errors, link offsets, and connection errors of two stages cause deviations with respect to the nominal structural parameters of the manipulator. If the nominal values of these parameters are used within the control software of the manipulator, the resulting pose of the end-effector will be inaccurate. In order to evaluate the effects of the above factors upon the pose accuracy, a vector arithmetic method is applied to establish the relations between the pose accuracy and manufacturing tolerances, actuation errors, and connection errors of two parallel mechanisms. Some results which are very useful to the design and manufacture of the micromotion manipulator are derived. The analysis method can also be used on the accuracy analysis of other type parallel or serial-parallel mechanisms.