Self-optimized, Intelligent Open-Loop-Controlled Steel Strip Straightening Machine for Advanced Formability
Innovative self-correcting process control techniques which adapt to the initial geometric characteristics of the strip are a promising approach to fix the local varying distortion of coiled strips by optimizing the leveling process. This paper presents an innovative strategy to improve straightening of AHSS materials (1.4310). This implies optimized leveling, adding minimal plastic deformation, and, thus, strain hardening. Therefore, an "intelligent straightening machine" is being developed which will be presented. To operate an intelligent straightening machine a reliable online measurement of the surface defects is fundamentally essential. This paper describes an approach towards the measurement of a bent steel strip for an automatic straightening process. Therefore, various ways of measuring the bending curvature are investigated. Optical, tactile, and the electromagnetic induction testing MagnaTest are compared with each other. The bending measurement is linked to open-loop control, providing an optimal straightening result in regards of formability, leveling, and reduced strain hardening.