The positron and rotational errors-also called pose et tot of the end-effector of a robotic mechanical system ate partly due to Its joints clearances: which are the play between their palling elements In this impel, we model the prediction of those errors by formulating two continuous constrained optimization problems (that. turn out, to hit NP-hard We show that techniques based On numerical constraint programming can handle globally and rigorously those hard optimization problems In particular, we present. preliminary experiments whole out global optimizer is very (competitive compared to the best-performing methods presented in the literature, while providing more robust results