The widespread use of mathematical applications, which include differential equations solvers, and the increase in the speed of computing devices have led to a decrease in interest in operator methods, in particular, the z-transform. Nevertheless, the use of the z-transform capabilities allows the implementation of efficient high-speed computing schemes with high numerical stability. The need for this may arise in the case of real-time simulation or the synthesis of digital control systems.
The unexploring problem of digital control systems analyzes in this article — the impact on their behavior of the limited bit resolution of the hardware and, accordingly, the discrete transfer functions coefficients. The research conducted by the zeros/poles and transient characteristics methods using the mathematical application MATLAB with the package Control System Toolbox and confirmed the relevance of this problem.
According to the theory of automatic control, there should be no behavior's difference between an object given by a set of transfer functions, which are respectively interconnected, and a real object, corresponding to such a theoretical structure with given transfer functions. Accordingly, a generalized analysis of the Otto Smith hypothesis regarding the stability indices in automatic control systems with unstable zeros and poles of second-order transfer functions is carried out.
Aim. The research aims to develop a method of optimal PI-controller tuning, which allows to take into account the constraints and to minimize the undesirable indicators of the automatic control quality. Method. In order to carry out the investigation, the problem of optimal PI-controller tuning was stated in a general form. The analysis of the elements of the problem has been conducted. It allowed substituting the elements to the requirements of individual minimization criteria.
The article discusses the use of structured characteristic equations to develop programs setting system variables. The relative units system designed for calculation of a set of options of automatic control. The possibility of using these units investigated to simplify the mathematical description of the system.
The goal of this paper is an experimental measurement of the frequency response of the software phase-locked loop (PLL) transfer function using frequency modulated signals.
The article is devoted to the approximation of fractional order differential-integral controllers by integer order transfer functions using the Oustaloup transformation. The dependence of the accuracy of practical approximation of fractional differential and integral units by the ratio of integer order polynomials on the Oustaloup transformation order has been examined.
The calculation of the coefficients of linear system transfer function with the lumped constant parameters which corresponds to the preset frequency response is present.
Calculation of the transfer function on a given frequency response is the optimization problem. Direct solution has multiextremal nonlinear optimization.
Hilbert transform is applied to calculate the minimum-phase phase response. Therefore, the optimization problem of calculating the coefficients of the transfer function has complex goal function with some restrictions.
The existing methods for assessing of the sensitivity of the polynomials roots of the transfer functions to changes in their coefficients were analyzed in this article. Particular attention was paid to the case of the multiple polynomials roots of the transfer functions, leading to a drastic impact of slightest error in polynomial coefficients on result of their roots finding. The basic mathematical equations for assessing the sensitivity of polynomials roots of the transfer functions to changes in their coefficients were described.