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 non-generic manipulators? 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. For instance, we show that generic manipulators, close to non-generic ones in the space of geometric parameters, are not robust with respect to their homotopy class and to the feasibility of paths. Moreover, we notice that the dexterity and the accuracy of 3R manipulator do not depend on genericity.