Kinematic principle and geometrical condition of general-linear-complex special configuration of parallel manipulators

It is complicated to analyze the special configuration (SC) of the parallel manipulator, especially the general-linear complex-SC (GLCSC). This paper studies the kinematic principle and geometrical condition for the GLCSC. Th ey are significant for understanding and searching this kind of SC. An alte rnative discriminant matrix D of the SC is presented at first. Then the unw anted screw motion is derived when the mechanism is singular. The kinematic principle and geometrical condition for GLCSC are revealed, and proved by some numerical examples. This method is very effective for typical 3/3- and 3/6-SPT parallel mechanisms. (C) 1998 Elsevier Science Ltd. All rights res erved.