Forward Kinematics of a General Fully Parallel Manipulator with Auxiliary Sensors

This paper presents a solution scheme for forward kinematics of a general fully parallel manipulator that guarantees a unique solution with only three redundant sensors. The redundant sensors were designed to minimize engineering difficulties in the realization, whereas an optimal sensor location was proposed to achieve a numerical efficiency and accuracy significantly better than existing solutions. As a result, the present approach is insensitive to misalignment of sensor location and measurement errors. Due to these merits, the present approach can handle joint misalignment due to machining error and assembly when it is applied to the task of self-calibration, which requires extreme precision. It is also suitable for applications in which real-time computation is needed. KEY WORDS—parallel manipulators, forward kinematics, redundant sensors