Tandem strip mill is a complex system composed of a plurality of working frames and auxiliary equipments, each frame is a multi-variable, nonlinear dynamic system, and interacts with the adjacent one by the moving steel strip. The strip mill system can be seen as a flexible multi-body mechanical system composed of multiple rigid and deformable bodies such as: frames, hydraulic equipment, roller system, moving strip et al. During the rolling process, relative movement occurs between the roll system and stock which contacting with each other at t...