An easily manufactured structure and its analytic solutions for forward and inverse position of 1–2–3-SPS type 6-DOF basic parallel mechanism

This paper proposes an easily manufactured structure for 1-2-3-SPS type 6-DOF basic parallel mechanism by splitting a triple spherical joint into three single spherical joints, which are arranged on a push rod dividually. Based on structural analysis, we obtain that the coupling degree of the mechanism is zero. Then a unified formulation of forward kinematics can be obtained by solving each basic kinematic chain successively. The forward position solutions are verified by performing an inverse position analysis. This closed-form solution, based on the structural analysis, do not need to deduce and solve a monobasic high power equation with complicated mathematic methods and is easy to accomplish real-time control and do some research of workspace and error analysis. In addition, the calculation is also very simple.