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Unformatted text preview: ts are toleranced, we can first compute each part’s tolerance envelope, and then compute the configuration space obstacle using the envelopes. However, this analysis is overly conservative because it ignores parameter dependencies. The correct method is to construct the C-space envelopes for pairs of parts as follows. First, compute the pairwise feature Minkowski difference as before. The vertices of segments bounding the Minkowski difference have explicit representations as functions of the vertices of Pi and Pj. Thus it is possible to compute their nominal positions and their partial derivatives. Next, we compute the outer tolerance envelopes of the pairwise features, and obtain an arrangement of elementary features, whose outer cell is the Cspace envelope of the obstacle. When C-space envelopes of obstacles are used in assembly analysis methods instead of the nominal obstacles, the analysis accounts for parameter dependency in the worst case variation of the parts in the assembly. We h...
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