A stereo-vision based compensation method for pose error of a 6-DOF parallel manipulator with 3-2-1 orthogonal chains

This paper puts forward an algorithm to compensate the pose error of a 6-DOF (six degrees of freedom) parallel manipulator based on stereo vision. Firstly, under the principle of rigid motion, the position and orientation are expressed by coordinates of three feature points which are not in a same line. At the same time, the position and orientation of the moving platform at current moment are also computed. Then, according to the kinematics model of parallel manipulator and its pose at the current moment, the input-values of the micro-displacement drivers are computed. At the end, these input-values are utilized to compensate the pose error of the moving platform. The simulation results demonstrate that the compensated curve of the parallel manipulator is fitting well with its actual curve.