On the motion of oblique bevel geared robot wrists

It is shown that the principle of superposition can be used to analyze the spatial motion of a bevel-geared three-roll wrist with nonzero oblique angle. The total motion of the wrist is decomposed into three independent component motions, which are easier to analyze. A superposition tabulation is then constructed to derive the relations among the three wrist-joint variables and three coaxial actuation variables. The approach is straightforward and can be adapted for analyzing the motion of other geared wrists that are variations of the wrist considered