Wide strip hot rolling mill runout roll table electric drive control system
The object for the research is the electric drive of the wide strip hot rolling mill runout roll table. The goal of the research is decreasing the operational loses spent on the roll table equipment. The means for reaching the goal are the developing of the roll table equipment diagnostic system and the improved algorithm for electric drive control system. In the article the description of the performed researches and the results of developed systems applying are present.
Speed Control Based on State Vector Applied for Electrical Drive with Elastic Connection
The paper is focused on issues related to the control of electrical drives with oscillations of state variables. The main problem deals with the construction of the mechanical part, which contains elastic elements used as a coupling between the motor machine and the load. In such cases, strict tracking of the reference trajectory is difficult, so damping of the disturbances is necessary. For this purpose, the full state vector of the object is applied as the feedback signal for the speed controller. This method is efficient and relatively easy to implement (including the hardware part). However, the control accuracy is dependent on the quality of the parameters identification and the invariance of the object. Thus, two adaptive structures are proposed for the two-mass system. Moreover, selected coefficients were optimized using metaheuristic algorithms (symbiotic organism search and flower pollination algorithm). After presentation of the preliminaries and mathematical background, tests were conducted, and the numerical simulations are shown. Finally, the experimental verification for the 0.5 kW DC machines was performed. The results confirm the theoretical concept and the initial assumptions: the state controller leads to the precise control of the drive with a long shaft; recalculation of the parameters can improve the work of the drive under changes of time constants; modern design tools are appropriate for this application.
Inverse resolution of the heat-transfer equation with internal heat source: Application to the quenching of steels with phase transformations
A method is described for calculating the time dependence of the temperature and heat flux (on heating and cooling) at the surface of a solid body. For a given ambient temperature and a known time-temperature function of an interior point, the surface heat flux is computed through an inverse conduction algorithm taking into account the nonlinear nature of the problem. Moreover, this algorithm includes the enthalpy of phase transformations. The influence of space and time steps on inverse calculations (precision, stability) is investigated. The method is then applied to thermal cases involving different transformations in steels.