A Suboptimal Design Approach to the Ring Diameter Control for Ring Rolling Processes

Abstract

Although the ring rolling process is now finding increasing applications in many wider fields, analytical design methodology for controlling the process has been little explored. This paper considers an analytical design approach to the problem of controlling the pressure roll motion which critically affects the quality of rolled products. For this purpose a suboptimal PID controller was designed based upon the nonlinear rolling process model, in order to control the pressure roll movement to track a desired ring diameter growth profile as close by as possible during the rolling cycle. A series of simulations was performed to demonstrate the effectiveness of this controller. The results show that the proposed suboptimal controller can produce rolled rings of closer dimensional tolerances as well as improve the tracking performance, as compared with nonoptimal controllers.