Title:New Horizons in Ultimate Response Dynamics of Hydraulic Cylinder Control in Rolling MillsAuthor(s):Reinhard Karl, Georg Keintzel, Helmut Kogler, Christoph Pröll, Rudolf ScheidlAbstract:Metal rolling is an important area of high end hydraulic servo-valve actuation. Besides automatic gap control (AGC) several other functional rolling mill units, like loopers or coilers, benefit from the excellent dynamical performance and the high force capacity of the hydraulic servo valve actuators. Despite the high load (up to 120 MN per stand) and the high operating frequencies (20-30 Hz) at which tons of heavy mill equipment have to be moved, a very high precision is required, going down to a few microns. Servo valves of ultimate frequency response are employed and the nominal flow rates are in the range of 50 - 1000 l/min at 35 bar pressure loss. The installed power per rolling stand is typically several MW. However, convergent vibratory effects caused by external exciters and also divergent vibratory effects occur in rolling mills and restrict the production. Several important vibratory effects are in the range up to 200 Hz. For advanced algorithms based on hydraulic actuators to counteract these effects, the requirement for the servo valves are certainly in the same range (with minimum phase delay). The industrial application of hydraulic actuators in this frequency range poses challenges as conventional design fails and advanced components and a bundle of additional measures are required since complex oscillation phenomena are generated. A test rig was set up to study the dynamic performance of the new actuation system. With this test rig the protection of the hydraulic supply lines from pressure pulsation that is strongly provoked in this high frequency range on the one hand and the sufficient penetration of the high operating frequencies into the AGC cylinder were studied. Acoustic phenomena may degrade the performance drastically with excessive pulsation in the supply lines and meagre response in the AGC cylinder. ...Booktitle:Proceedings of the 21th International Conference on Hydraulics and Pneumatics, Ostrava, Czech Republic, 1-3 June 2011Editor(s):P. SmutnýISBN:978-80-248-2430-7Page Reference:page 13-20, 8 page(s)Publishing:6/2011