This preview shows page 1. Sign up to view the full content.
Unformatted text preview: AT) have been developed over the years, for example variational classes [Requicha 1984,1983], vectorial tolerancing [Wirtz 1998][Weber et al.1999] or linear programming approaches [Pradeep et al. 2005][Angus 2001][WEI 1997] just to name a few. Of concern in this paper are the Jacobian and torsor approaches [Ghie 2004]. [Desrochers et al. 03]. The former is based on small displacements modeling of points using transformation matrices of open kinematic chains in robotics. The latter models the extreme limits of 3-D tolerance zones resulting from a feature’s small displacements using a torsor representation with constraints. Both of them fall under the category of kinematic approaches to tolerancing. The kinematic approach is also used by many other researchers and is also at the base of at least one successful commercial implementation of a CAT system [Hong et al. 2002]. Thus the kinematic CAT model is built on top of existing CAD nominal information and its matrix formulation makes it compatible for performing the required computations natively in the CAD system. Barraja M [Bararaja et al. 2005] presents a method for allocating tolerances to the dimensions of the kinematic couplings. The objective is to reduce the manufacturing cost without exceeding limits on the variation of the coupled position and orientation. This method uses parametric models of the contacting surfaces and a solution for the resting position of the coupled bodies. The tolerances of the coupled bodie...
View Full Document
- Spring '10
- The Land