The locations of components in mechanical assemblies are determined by
reconciling various constraints among the components that arise from
physical, geometric and kinematic relationships, human factors, mainte
nance concerns, etc. Among them some constraints require that particul
ar spatial relationships between components be maintained exactly, i.e
., equality constraints. In general the equality constraints can be ex
pressed as systems of equations. However the systems of equations dedu
ced from the equality constraints are mostly ill-determined so that sp
ecial numerical attentions are required. This paper proposes a numeric
al treatment for ill-determined systems in mechanical assemblies. It u
tilizes singular value decomposition and Newton-Raphson methods in cor
poration with minimum weighted deviation criteria. The treatment was i
mplemented on an assembly modeler for automatic packaging task.