Feasibility analysis of displacement trajectories for robot manipulators with a spherical wrist

The author describes a method by which to determine the feasibility of displacement trajectories of a class of robot manipulators, namely, those with a wrist of intersecting axes. The author obtains the workspace description of a robot manipulator in general using workspace analysis based on polynomal discriminants, and shows the simplicity of the workspace description of the PUMA 560 in particular. Taking advantage of that simplicity, he then shows that there exist convenient algebraic equations that require minimum computation and enable the feasibility of displacement trajectories to be evaluated in some cases without using inverse kinematics