No 4 (2023)
Analysis and Design of Control Systems
Parametric Optimization of a Nonlinear Model in Tumor Cell Growth Identification
Abstract
This paper presents an identification method for time-varying objects that involves mathematical models with parametric tuning. The deviation of object’s transients and its mathematical model are estimated in terms of a quadratic performance criterion; the parametric tuning of the object model is a constrained optimization problem. The parametric optimization algorithm is developed using the vector projection property in a Krein space and the second Lyapunov method for a targeted change in the model parameters. The method is applied to estimate parameters in a tumor cell growth model. The nonlinear model describes the relationship between the populations of normal, immune, and tumor cells that can be measured in the presence of Gaussian white noise. Numerical simulation illustrates the design procedure and shows the effectiveness of this method.
Control Sciences. 2023;(4):3-13
3-13
Control in Social and Economic Systems
Models of Joint Dynamics of Opinions and Actions in Online Social Networks. Part III: Binary Models
Abstract
Based on VKontakte data, we study the influence of various factors on the dynamics of opinions and actions both at the macro level (“public opinion”) and at the micro level (opinions and actions of individual agents). This paper concludes the multi-part study. Identification results are presented for binary models (threshold models and models with latent variables) that describe the dynamics of agents’ opinions and actions in a social network. These models are used to estimate the influence of various factors on agents’ opinions and actions (public opinion, the agent’s individual opinions and actions, the opinions and actions of the social environment, and the mechanisms of the agent’s trust in information sources and information content). Finally, linear models are compared with threshold models and qualitative findings of the multi-part study are drawn.
Control Sciences. 2023;(4):14-27
14-27
Control of Technical Systems and Industrial Processes
Identification-Based Speed Control of an Overhead Crane with a Reduced Cargo Transfer Model
Abstract
This paper considers an automatic control approach for an overhead crane trolley under the current parametric uncertainty of the crane, transported cargo, and exogenous disturbances. It generates a given trolley speed, which corresponds to the modern hardware implementation of control of cranes with asynchronous motors and frequency converters. The approach is based on a control scheme with a current parametric identification algorithm, an implicit reference model, and “simplified” adaptability conditions to track cargo movements directly. This algorithm involves a recursive least-squares method with the forgetting factor. Unlike previous publications on the topic, the idea is to use a reduced model of the “crane–cargo” object when moving the cargo along one horizontal axis. In this case, it is necessary to estimate only two parameters; moreover, the construction of the control algorithm becomes simpler and the closed-loop control system has a better performance. The stability of the closed-loop control system is proved and requirements for the parameters of the assigned reference motion are found. Due to the self-tuning property of the control system, the approach can be obviously generalized to construct an overhead crane control system along two horizontal axes and three axes (with simultaneous vertical movement of the cargo). A model example is given to demonstrate the implementability of this crane control system based on modern controllers and sensors.
Control Sciences. 2023;(4):28-37
28-37
Control of Moving Objects and Navigation
Aircraft Motion Control Algorithms for Airborne Geophysical Survey
Abstract
In an airborne geophysical survey, the control of moving objects requires forming optimal program (reference) trajectories. Optimality criteria differ depending on the tasks to be performed. The most obvious criterion is the time in which an object reaches its final position from an initial position. Problems with such a criterion are known as time-optimal control problems. This paper considers two control problems of this class related to the performance of a flight task by an aircraft during an airborne geophysical survey. Such a survey is traditionally carried out along a network of parallel routes. Accordingly, the first mode is to start the next survey route. The second mode is to approach the current straight segment of the route. The corresponding time-optimal control problems are posed and solved. The resulting solutions are the reference trajectories for the start and approach modes. The solutions are formally analyzed and methods for forming optimal trajectories and the corresponding controls implementing these trajectories are described. The onboard software implementation of these algorithms is described.
Control Sciences. 2023;(4):38-47
38-47
Inter-orbital Spacecraft Transfer Optimization: Choosing Initial Approximations Based on Correlation Analysis of Key Parameters
Abstract
This paper presents a new approach to choosing initial approximations in inter-orbital transfer optimization problems for a spacecraft with a chemical booster and fixed thrust. The approach involves correlations between the values of key problem parameters. It is implemented using numerical methods, mathematical modeling, and programming. Relevant publications on the subject area (methods for finding initial approximations in optimization problems) are systematically studied and several mathematical relationships are identified. As a result, laws are specified to facilitate the choice of initial approximations in order to ensure convergence and achieve the optimum. The results of a computational experiment confirm the applicability and effectiveness of this approach in typical optimization problems (an optimal spacecraft trajectory design between near-Earth orbits as one example).
Control Sciences. 2023;(4):48-56
48-56