№ 1 (2023)
Articles
Stability Analysis of Mechanical Systems with Highly Nonlinear Positional Forces under Distributed Delay
Аннотация
This paper considers mechanical systems with linear velocity forces and highly non-linear positional forces containing distributed-delay terms. Asymptotic stability conditions of system equilibria are proved using Lyapunov’s direct method and the decomposition method. The developed approaches are applied to the monoaxial stabilization of a solid body. The theoretical outcomes are confirmed by computer simulation results.
Relaxation of Conditions for Convergence of Dynamic Regressor Extension and Mixing Procedure
Аннотация
A generalization of the dynamic regressor extension and mixing procedure is proposed, which, unlike the original procedure, first, guarantees a reduction of the unknown parameter identification error if the requirement of regressor semi-finite excitation is met, and second, it ensures exponential convergence of the regression function (regressand) tracking error to zero when the regressor is semi-persistently exciting with a rank one or higher.
Optimal Retention of the Trajectories of a Discrete-Time Stochastic System in a Tube: One Problem Statement
Аннотация
This paper considers an optimal control problem for a time-invariant linear stochastic system with discrete time, scalar unbounded control, additive noise, and a probabilistic criterion for retaining its trajectories in a given neighborhood of zero. We use dynamic programming and two-sided Bellman function estimates to derive analytical expressions for the optimal control at two time steps and a suboptimal control on any control horizon. The effectiveness of these controls is illustrated on a numerical example.
Upravlenie poiskom ob"ektov nablyudeniya iz prostranstvenno-vremennogo puassonovskogo potoka v mnogokanal'noy poiskovoy sisteme
Аннотация
Randomized Machine Learning Algorithms to Forecast the Evolution of Thermokarst Lakes Area in Permafrost Zones
Аннотация
Randomized machine learning focuses on problems with considerable uncertainty in data and models. Machine learning algorithms are formulated in terms of a functional entropy-linear programming problem. We adapt these algorithms to forecasting problems on an example of the evolution of thermokarst lakes area in permafrost zones. Thermokarst lakes generate methane, a greenhouse gas affecting climate change. We propose randomized machine learning procedures using dynamic regression models with random parameters and retrospective data (climatic parameters and remote sensing of the Earth’s surface). The randomized machine learning algorithm developed below estimates the probability density functions of model parameters and measurement noises. Randomized forecasting is implemented as algorithms transforming the optimal distributions into the corresponding random sequences (sampling algorithms). The randomized forecasting procedures and technologies are trained, tested, and then applied to forecast the evolution of thermokarst lakes area in Western Siberia.
Iterative Learning Control of a Discrete-Time System under Delay along the Sample Trajectory and Input Saturation
Аннотация
This paper considers a linear discrete-time system operating in a repetitive mode to track a reference trajectory with a required accuracy. The control variable has a delay along the sample trajectory, and saturation-type constraints are imposed. We introduce a new method for designing an iterative learning control law that depends on the delay and ensures the required accuracy of tracking. A numerical example demonstrates the effectiveness of this method.