No 4 (2024)
Analysis and Design of Control Systems
Robust Controller Design Ensuring the Desired Aperiodic Stability Degree of a Control System with Affine Uncertainty
Abstract
This paper considers a system whose characteristic polynomial coefficients are linear combinations of the interval parameters of a plant forming a parametric polytope. A linear robust controller is parametrically designed to place a dominant pole of the system within the desired interval of the negative real semi-axis and ensure an aperiodic transient in the system. The parametric design procedure involves a low-order controller with dependent and free parameters: the former serve to place the dominant pole within the desired interval on the complex plane whereas the latter to shift the other poles to some localization regions beyond a given bound (to the left of the dominant pole to satisfy the pole dominance principle). To evaluate the dependent parameters of the controller, the originals of the interval bounds of the dominant pole are determined for the plant’s parametric polytope based on a corresponding theorem (see below). The free parameters of the controller are chosen using the robust vertex or edge D-partition method, depending on the boundary edge branches of the localization regions of the free poles. A numerical example of the parametric design procedure is provided: a PID controller is built to ensure an acceptable aperiodic transient time in a load-lifting mechanism with interval values of cable length and load weight.
Control Sciences. 2024;(4):3-12
3-12
Information Technology in Control
Investigation of Tandem Queuing Systems Using Machine Learning Methods
Abstract
This paper considers tandem queuing systems with limited buffer sizes in each phase. The system handles an incoming correlated MAP flow and the service time obeys a PH-distribution. Models of such systems and methods for their investigation are briefly reviewed from the historical perspective. According to the review, the problem statement presented below, the methods proposed for solving this problem, and the corresponding results are novel. An accurate algorithm for calculating the performance characteristics of low-dimensional tandem queuing systems is described, including an estimate of the algorithm’s complexity. An approach using both machine learning and simulation modeling is suggested for the investigation of high-dimensional tandem queuing systems. Numerical analysis results are provided to show the effectiveness of machine learning methods for estimating the performance of tandem queuing systems.
Control Sciences. 2024;(4):13-25
13-25
Design of Self-Checking Digital Devices with Boolean Signals Correction Using Weight-Based Bose-Lin Codes
Abstract
This paper proposes a method for designing self-checking digital devices with Boolean signals correction and weight-based Bose–Lin codes. Unlike previous studies, the method involves Boolean signals correction (BSC) in the concurrent error-detection (CED) circuit for those functions describing the outputs of source devices that participate in the formation of data symbols of weight-based Bose–Lin codes. In such codes, as in the absolute majority of uniform separable codes, large number of data vectors correspond to the same check vector; therefore, it is possible to choose a method for determining BSC functions. We describe an algorithm for determining their values for each input combination, considering the testability of the checker and transformation elements in the CED circuit. The method involves the so-called “base” structure for monitoring multi-output devices by output groups. With this method, the designer of a self-checking device has high variability in choosing the design method and can regulate important indicators (structure redundancy, controllability, energy consumption, and others). Experiments with combinational benchmarks from MCNC Benchmarks were carried out. According to the experimental data, the method has high efficiency in terms of structure redundancy compared to the duplication method widespread in practice. The method can be effective when designing real devices with fault detection used in all areas of technology, including critical application systems in industry and transport.
Control Sciences. 2024;(4):26-43
26-43
An Entropy-Based Composite Indicator for Evaluating the Effectiveness of Recommender System Algorithms
Abstract
The problem of forming a composite indicator for evaluating the effectiveness of recommender system algorithms is considered. A novel composite indicator is proposed by combining individual metrics using the entropy method. The testing base of this study consists of 12 algorithms (on the one hand) and 3 datasets (on the other). For each algorithm–dataset combination, we calculate partial criteria used in evaluating recommender systems. According to the results presented below, the composite indicator is an effective tool for evaluating the performance of recommender system algorithms. As is shown, the performance of the algorithms varies depending on the size and other basic characteristics of a particular dataset. This indicator can be used to develop more efficient algorithms and their ensembles as well as to optimize hyperparameters and improve the quality of recommendations.
Control Sciences. 2024;(4):44-60
44-60
Control of Technical Systems and Industrial Processes
An Identification-Based Control Method for an Overhead Crane with a New Combined Sensor Placement
Abstract
This paper is devoted to an automatic control method for an overhead crane under the current parametric uncertainty of the crane, transported cargo, and exogenous disturbances. The control objective is to move the cargo in the horizontal plane to a point ensuring the final delivery of the cargo to the designated place while parrying the angular oscillations of the suspension and reaching given dynamic characteristics. 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. The control law generates a given trolley speed for the servo drive. The passport data of the crane installation are used to select the control law parameters. Unlike previous publications on the topic, the solution proposed below is simpler, more reliable in terms of operation, and less expensive. This is achieved by placing a combined sensor (an accelerometer with an angular rate sensor (ARS)) on a suspension cable near the crane trolley and applying, first, an algorithmic solution without the preliminary calculation of the ARS drift and, second, a current parametric identification procedure of higher efficiency. Computer simulation results are provided to confirm these advantages of the new solution. A similar example is implemented on an experimental installation.
Control Sciences. 2024;(4):61-73
61-73