A unified approach to the kinematic analysis of joint clearances and link length tolerances for determination of the rotational and positional accuracy of planar mechanisms

A unified approach to the kinematic analysis of joint clearances and link length tolerances in general mechanisms is presented, expressly with the purpose of predicting the error in both rotational and positional accuracy of planar and spatial mechanisms. Rather than applying stochastic estimation or deterministically-based approximations based on a Tavlor series expansion approach, this new method ob;ains the exact mechanical error based on a combination of approaches including the principle of virtual work, pertinent geometrical relations, and kinetostatic analysis. Computer-based kinematic designs for the Schmidt coupling, a parallel-jaw straight-line path generator and a sinusoidal function generator have been included as representative real-world. design examples, for determination of their maximum mechanical error and error sensitivity to link length tolerances and joint clearances. The computer-aided approach presented in this paper is particularly attuned to the needs and requirements of industrial precision mechanism d • 1•n providing definitive information, which es1gners is directly applicable to the determination of kinematic error effects due to manufacturing tolerances, on the accuracy of mechanisms.