Investigation of Self-Oscillations and the Development of a Procedure of Stabilization of the Process in a Continuous Mi
- PDF / 1,637,416 Bytes
- 10 Pages / 594 x 792 pts Page_size
- 119 Downloads / 180 Views
INVESTIGATION OF SELF-OSCILLATIONS AND THE DEVELOPMENT OF A PROCEDURE OF STABILIZATION OF THE PROCESS IN A CONTINUOUS MILL FOR STRIP COLD ROLLING A. V. Kozhevnikov,1 A. S. Smirnov,2 I. A. Kozhevnikova,3 P. V. Antonov,4 S. V. Zhilenko,5 and A. I. Aralov6
UDC 621.771
We study the problem of operation of sheet rolling mills under the conditions of nonstationary technology, the stochasticity of the parameters in the presence of negative self-oscillation vibration processes associated with the “chatter” phenomenon. We determine the parameters of stability of the process of sheet rolling, reveal the main causes of the chatter phenomenon, and describe the mechanism of their initiation. We also propose a procedure for the identification of this phenomenon by continuous statistical processing of the parameters of rolling process. As a result of the performed investigations, we developed a method aimed at the adjustment of the technology, which excludes vibration and enables us to enhance the productivity of rolling mills by means of increasing the average speed of rolling. Keywords: unsteadiness of the sheet rolling process, “chatter” phenomenon, vibration in sheet rolling mills, identification and elimination of vibration.
In view of its unsteadiness and instability, the technological process of rolling is not deterministic. The subsequent state of the parameters of this process can be described by the quantities of random nature and/or can be predicted. Therefore, the technological process of rolling, including the operation of its electromechanical, automated, and automatic systems, is actually stochastic (random) process. Moreover, vibration processes with a constant speed are sustained and have a certain amplitude. Therefore, they are determined by the properties of the system [1]. Thus, its behavior corresponds to the notions “self-oscillating system” and “self-oscillations,” introduced by A. Andronov and A. Vitt [2, 3] who were the founders of the theory of nonlinear oscillations in the 1930–1950s under the guidance of A. Mandel’shtam. The stochastic character of technological process and the presence of self-oscillations negatively affect the operation of technological equipment. The units of working rolls in the stands of rolling mills often exhibit the formation of vibrations frequently passing into the dangerous resonance phase, which corresponds to the emergency conditions of operation of the mill. Vibration processes appear, as a rule, under the dynamic conditions in passing to the elevated speeds of rolling. Thus, the productivity decreases and the quality of the metal surface becomes worse [4–10]. This problem is urgent not only for the domestic but also for the foreign cold-rolling mills. The self-oscillations (vibration) formed in these mills were called “chatter” [4]. The phenomenon of chatter (i.e., undesirable 1 2 3 4 5 6
Cherepovets State University, Cherepovets, Russia; e-mail: [email protected].
Cherepovets State University, Cherepovets, Russia; e-mail: mr.shagrat.91@mail-ru. Cherepovets State Universi
Data Loading...
