Robustness Study of Generic and Non-Generic 3R Positioning Manipulators

This paper presents a robustness study of 3R manipulators and aims at answering the following question: are generic manipulators more robust than their non-generic counterparts? We exploit several properties specific to 3R manipulators such as singularities, cuspidality, homotopy classes, and path feasibility, in order to find some correlations between genericity and robustness concepts. It turns out that the farther a manipulator is from non-generic ones, the more robust it is with respect to homotopy class and number of cusps. Besides, we state that the proximity of a manipulator to non-generic frontiers may severely affect its robustness with respect to path-feasibility. Finally, we notice that the dexterity and the accuracy of 3R manipulators do not depend on genericity. Keywords—Robust design, genericity, path-feasibility, singularity, cuspidality, homotopy class, serial manipulator.