Determination of the orientation workspace of parallel manipulators

An important step during the design of a parallel manipulator is the determination of its workspace. For a 6 d.o.f. parallel manipulator workspace limitations are due to the bounded range of their linear actuators, mechanical limits on their passive joints and links interference. The computation of the workspace of a parallel manipulator is far more complex than for serial link manipulator as its translation ability is dependent upon the orientation of the end-effector. We present in this paper an algorithm enabling to compute the possible rotation of the end-effector around a fixed point. This algorithm enables to take into account all the constraints limiting the workspace. Various examples are presented.