REAL-TIME DIRECT KINEMATICS OF GENERAL 6-DEGREE-OF-FREEDOM PARALLEL MANIPULATORS WITH MINIMUM-SENSOR DATA

We present a formulation of the direct kinematics of a general six-deg ree-of-freedom parallel manipulator, sometimes referred to as the gene ralized Steward platform, whereby the positioning and orientation prob lems are decoupled by introducing two auxiliary coordinates in the for ms of either two angles or two lengths. This is in accordance with the type of extra sensors, i.e., rotary or translational, that are colloc ated on a leg of the manipulator. Moreover, a real-time implementation of extra-sensor data, with a unique direct kinematics solution, is pr oposed by resorting to an eigenvalue problem. The parallelism in the p roposed formulation enables the user to benefit from a parallel comput ing environment. Hence, we introduce a parallel computing algorithm th at highly increases the robustness of the computational algorithm. (C) 1995 John Wiley & Sons, Inc.