Quantitative measures are determined for the evaluation of the structu
ral properties of nonlinear processes. These include simple structural
measures for the evaluation of the ''best'' achievable control qualit
y in a given process, regardless of the type of the controller being u
sed. The notions of relative orders (time delays) with respect to mani
pulated inputs and disturbances and characteristic matrix are used to
determine the best achievable closed-loop response for each controlled
output and to derive the conditions under which the best closed-loop
response in all outputs together with complete input-output decoupling
is feasible.