Local structurization for the forward kinematics of parallel manipulators using extra sensor data

This paper presents a new extra sensing approach of local structurization to the forward kinematics of 6-DOF Stewart platform manipulators (SPMs). It is shown that one extra sensor is sufficient for both a 3-3 SPM and a 6-3 SPM to exactly resolve the forward kinematic problem (FKP) of the SPMs in closed form, two for a 6-6 SPM. In previous researches, at least three extra sensors were needed for closed-form resolution of the FKP of a 6-6 SPM. As a basis for the new approach, two concepts, local structurization and mechanism partition, are introduced. The new scheme is described with graphical illustrations and verified through numerical examples. Consequently, the new scheme is suitable to real implementation, because its computation is very efficient