UDC 519.711
DIGITAL SDRE-CONTROLLER OF LIQUID LEVEL FOR OBJECTS OF PETROCHEMICAL INDUSTRY
A. I. Bobikov, Ph.D. (Tech.), associate professor, Department of Automation and Information Technologies in control, RSREU, Ryazan; This email address is being protected from spambots. You need JavaScript enabled to view it.
O. N. Burkina, graduate student, RSREU, Ryazan; This email address is being protected from spambots. You need JavaScript enabled to view it.
A modification of continuous SDRE-controller based on Lie series expansion, by introducing constant coefficients in the terms of control law to simplify computational operations and eliminating rounding errors, as well as further optimization with the help of two methods: optimization of introduced coefficients by means of Simulink Response Optimization packet and MATLAB system Optimization Toolbox usage is proposed. The aim of the work is to redesign a continuous regulator into a digital controller for a nonlinear system using the Lyapunov control / function matching technique. The main idea of the Lyapunov control / function matching method for a nonlinear digital system is to find a digital state controller such that its efficiency in terms of the closed loop Lyapunov function is the same as for the desired control strategy for a continuous system with state feedback. The approach proposed gives an approximate 38 times decrease in integral quadratic error value for a synthetic control object, and for a real object in the form of a spherical reservoir – an approximate 1,23 times decrease.
Key words: state-dependent Riccati equation, digital control, sampling period, emulation, Lie series, Lyapunov input / function matching, Lie derivatives, order of approximation.