Combined Control System Research Articles

METHODS OF MATHEMATICAL MODELING OF THE POWER CHARACTERISTICS OF A WIND TURBINE

At the moment, the Russian wind energy market uses wind power plants, which have their own range of parameters and characteristics. There are also various methods by which it is possible to calculate electricity generation by nominal capacity and wind potential data for the site where the construction of a wind farm is planned. But for this, it is necessary to have a power characteristic for a particular wind power plant. The nominal wind speed is often used for its construction. (Research purpose) Applied analytical and computational methods, in particular the Binov method, the method of approximation of the function - linear interpolation, this is a way to calculate the intermediate value of the function from its already known several values. (Materials and methods) Applied analytical and computational methods, in particular the Binov method and the linear interpolation method. (Results and discussion) Formulas for calculating wind speed and active power for constructing power characteristics using the Binov method were given. Approaches to modeling the power characteristic and its approximation are described. At the same time, we took into account the features of power management systems, which are divided into active, passive and combined. The results of calculations were presented in tabular form, indicating that cubic polynomials cannot be used with passive and combined control systems due to a large approximation error; this indicates that common methods for determining power and output do not always give accurate results. (Conclusions) Several mathematical models used to analyze the power characteristics of wind power plants have been demonstrated. They have shown that they can be used to predict production for given sites with a known wind regime.

Degree of encountering of representatives of the family of poultry in the solanaceae family grown in greenhouses

We have set ourselves the main goal of identifying the types of thrips that cause serious damage to the members of the family of the ituzum family grown in greenhouses, their level of occurrence, and mainly to give recommendations for the production of thrips-resistant varieties of Bulgarian pepper. At the same time, the introduction of the improvement of the combined control system by studying the stations and gradations between insects, population density in greenhouses. The organization of the cultivation of vegetable products that is ecologically clean and in accordance with international standards is a partial solution to the main pressing issues facing the agricultural workers today.

Синтез модельно-прогнозуючого регулятора режиму дуття киснево-конвертерного процесу

The purpose of the research was to find a solution for a decrease in the cost price of the basic oxygen furnace steel. It is conditioned by an increase in the scrap metal portion due to an increase in the СО to CO2 afterburn degree in the basic oxygen furnace cavity according to the optimal model predictive control of the parameters of the blowing mode. The optimal parameter control system was synthesized for the blowing mode of the oxygen-converter melting on the basis of the feedback based on the model-predictive control using the linear-quadratic functional and it enabled a simultaneous control of the blowing intensity and the lance position when programmatically changing the task for the oxygen consumption and CO2 content improving also the control quality and energy saving during the melting process due to an increased afterburn degree during the CO to CO2 conversion that is a consequence of an increased portion of the scrap metal. Closed CO to CO2 afterburn degree control systems were improved by the synthesis of the model-predictive controller taking into consideration process limitations imposed on the shifting rate of controlling mechanisms, improving thus the process control quality in the case of the limitations. The suggested solution enables certain process control quality improvement under the conditions of process limitations. A comparative investigation of the operation of the model – predictive controller and combined control system with PID–controllers showed that the obtained transition processes of the automatic control of the blowing mode for the basic oxygen furnace melting using the automatic model-predictive controller provided ISE values for the oxygen consumption loop equal to 5577 and the CO2 content equal to 43 in basic oxygen furnace gases with a maximum dynamic deviation of the CO2 content in converter gases equal to 0.95 %. The use of the model-predictive controller allowed us to improve the control quality for the oxygen consumption loop by a factor of 1.63 CO2 and by a factor of 32.5 for the CO2 content control loop in converter gases. A maximum dynamic deviation of the CO2 content in converter gases was reduced by 16.55 % in comparison to that in the combined control system equipped with PID-controllers.

QUASI-ANALYTIC METHOD OF LINEAR DYNAMIC SYSTEMS INVERSION

The problem of inversion of dynamic systems has become widespread while solving the problems of control, identification, and measurement problems arising during the design and research of electrical and mechanical dynamic systems. Inverting is an effective way of implementing disturbance control processes, as well as in combined control systems with a predictive model. The analysis of information sources showed that in the practical solution of most inversion problems, a number of difficulties arise, which are associated with the high sensitivity of the results in relation to the accuracy of the parameters of the mathematical model of the control object, the instability of the inverse model of non-minimum-phase objects, and the violation of the conditions of physical feasibility. The work offers an effective method of inverting linear stationary dynamic systems, free from the mentioned shortcomings in many respects. The basis of the method is the presentation of input and output signals in the form of infinite linear combinations of their derivatives. A method of determining the sequence of matrix coefficients of linear representations of input and output signals is proposed. The main theoretical result is obtaining relationships between matrix coefficients of input and output signals. The work considers mathematical models of linear dynamic systems in the form of differential equations in the state space and in the equivalent "input-output" form. The considered systems must meet the conditions of asymptotic stability, as well as the condition of equal dimensions of the input and output vectors. Requirements for mathematical models of input and output signals are given, the fulfillment of which allows, instead of infinite sums representing signals, to be limited to a finite number of terms.

Interval Fuzzy Type-2 Sliding Mode Control Design of Six-DOF Robotic Manipulator

The remarkable features of hybrid SMC assisted with fuzzy systems supplying parameters of the controller have led to significant success of these control approaches, especially in the control of multi-input and multi-output nonlinear systems. The development of type-1 fuzzy systems to type-2 fuzzy systems has improved the performance of fuzzy systems due to the ability to model uncertainties in the expression of expert knowledge. Accordingly, in this paper, the basic approach of designing and implementing the interval type-2 fuzzy sliding mode control was proposed. According to the introduced systematic design procedure, complete optimal design of a type-2 fuzzy system structure was presented in providing sliding mode control parameters by minimizing tracking error and control energy. Based on the proposed method, the need for expert knowledge as the main challenge in designing fuzzy systems was eliminated. In addition, the possibility to limit the control outputs to deal with actuators’ saturation was made available. The control method was implemented on a six-degree-of-freedom robot manipulator that was exposed to severe external disturbances, and its performance was compared to a type-1 fuzzy system as well as to the conventional SMC. The achievements revealed improved performance of the combined control system of fuzzy sliding mode type-2 in comparison with its control counterparts.

OPTIMIZATION OF THE BARGE-TOWING COMBINATIONS CONFIGURATION DEPENDING ON THE OVERALL AND NAVIGATIONAL CHARACTERISTICS OF INLAND WATERWAYS

The organization of transportation by inland water transport involves taking into account the overall characteristics and navigational features of waterways, the choice of a vessel to work on the route, ensuring the safety of navigation and the economic efficiency of the voyage. One of the main advantages of barge-towing combinations is the possibility of their formation according to the specified dimensions of the waterway. The purpose of this work is to overcome the linear approach currently used in the formation of the ship’s composition, and to develop mathematical foundations for describing the barge-towing combination control system, a particular task is to optimize the barge-towing combination structure for local restrictions of waterway sections. To solve this problem, the possibility of reorganizing the ship’s composition directly on the route, depending on the conditions for the passage of a particular section of inland waterways is supposed to study in the work; it in the future will improve the transportation efficiency and ensure the transportation of more cargo per voyage. For the mathematical description of inland waterways, their natural characteristics are used in the work, sections coincided in restrictive features are identified, that is, each section of inland waterways, depending on its type, has a certain set of restrictions related to overall characteristics that must be taken into account when organizing navigation. The simulation of the movement of a ship’s combination along sections of waterways of various types, including a curved section, performed by graphic-analytical methods, shows the limitations arising when entering a turn and passing through artificial narrowings of the fairway, and also reflects the ability to pass the entire route due to a change in configuration when maintaining the total carrying capacity of the ship’s combination. As a result, mathematical relations and a system of inequalities that determine the choice of a section of inland waterways for the operation of ship’s combinations in a certain (specified) configuration and planning their reformation according to the given characteristics of the waterway are obtained.

A review of path following control strategies for autonomous robotic vehicles: Theory, simulations, and experiments

AbstractThis article presents an in‐depth review of path following control strategies that are applicable to a wide range class of marine, ground, and aerial autonomous robotic vehicles. From a control system standpoint, path following can be formulated as the problem of stabilizing a path following error system that describes the dynamics of position and possibly orientation errors of a vehicle with respect to a path, with the errors defined in an appropriate reference frame. In spite of the large variety of path following methods described in the literature we show that, in principle, most of them can be categorized in two groups: stabilization of the path following error system expressed either in the vehicle's body frame or in a frame attached to a “reference point” moving along the path, such as a Frenet‐Serret (F‐S) frame or a Parallel Transport (P‐T) frame. With this observation, we provide a unified formulation that is simple but general enough to cover many methods available in the literature. We then discuss the advantages and disadvantages of each method, comparing them from the design and implementation standpoint. We further show experimental results of the path following methods obtained from field trials testing with under‐actuated and over‐actuated autonomous marine vehicles. In addition, we introduce open‐source Matlab and Gazebo/ROS simulation toolboxes that are helpful in testing path following methods before their integration in the combined guidance, navigation, and control systems of autonomous vehicles.

Dynamic investigation of centralized and decentralized storage systems for a district heating network

District heating is an efficient and promising way to cover the residential space-heating and domestic hot water needs, resulting in economic and environmental benefits, especially if operated by renewable power stations, when compared to fossil fuels. In this direction, the present study investigates in detail a district heating network with novel decentralized storage for domestic hot water (enerboxx scenario), over centralized storage systems, applying a specific schedule-based approach for the coordinated hot water tank charging. The goal of this design is to properly control the system by charging it at predetermined time periods during the day aiming at i) diminishing the thermal losses and ii) reducing the thermal demand from the grid, over the period of a day. The simulation is conducted with a newly developed component-based tool, called INTEMA, which is based on the Modelica language. This encompasses the ability to discretize with high temporal resolution and adjustable time steps the overall grid configuration, with the support of customizable level of detail models for simulating key system components such as the storage tanks, the piping and the dwelling needs, as well as the application of an advanced control system over the district heating network and the dwellings. More specifically, a combined control system that controls both operating parameters in the network and inside the dwellings is applied. The developed system model is verified against available data for a standard centralized storage system (reference scenario) and afterwards, the novel decentralized design is compared against corresponding results of the standard system, as concerns key operational parameters; indicatively the temperature levels of the hot water and the heat load demand. The analysis is conducted for a heating network of 9 dwellings in Austria, which have an underfloor heating system, a system for covering the domestic hot water demand, considering also that each of these 9 dwellings is characterized by a unique demand profile. It was found that the decentralized approach leads to lower demand and there are energy savings of 18 % compared to the reference scenario, while the thermal losses are reduced by about 22 %. Moreover, a parametric study regarding the storage tank volume and the heat exchanger thermal transmittance in the tank is conducted, in order to examine the impact of these design parameters on the system dynamic behavior.

Minimizing the surface roughness in L-PBF additive manufacturing process using a combined feedforward plus feedback control system

Minimizing the surface roughness in L-PBF additive manufacturing process using a combined feedforward plus feedback control system

Combined Control System for the Coordinates of the Electric Mode in the Electrotechnological Complex “Arc Steel Furnace-Power-Supply Network”

To stabilize the electrical mode of an arc steelmaking furnace in the initial stages of melting, it is advisable to use a high-speed current-limiting system, in addition to the traditional electrode movement control system. This system is implemented by including the primary winding of the furnace transformer choke, controlled by thyristors. The use of such a system, on the one hand, reduces the negative impact of the arc steel furnace on the the power supply network operation and, on the other, affects the operation of the electrode movement system, built on the principle of an impedance regulator. In order to analyze the mutual influences between such systems, a mathematical model for the power supply and control system of the arc steelmaking furnace was created. The developed model can work in real time, which corresponds to the world trends of modern control system synthesis for complex technological objects. In the created model, the work of the combined control system with different approaches to the formation of the control effect in the high-speed circuit and the effect of the combined control system on the power supply system of the ASF are analyzed.

Wind-Storage Combined Virtual Inertial Control Based on Quantization and Regulation Decoupling of Active Power Increments

With the increasing proportion of wind turbines in power grids, they are required to have capabilities of active and efficient virtual inertial response to maintain grid frequency stability. However, the virtual inertial control methods currently used in doubly-fed induction generator (DFIG) units suffer from a secondary frequency drop (SFD) problem. Although the SFD can be inhibited by reducing the active power support strength of the DFIG units during inertia response, it will undoubtedly weaken the virtual inertia of the units. Therefore, how to eliminate the SFD while increasing the virtual inertia of the units is a worthy issue for studying. To solve this issue, a wind-storage combined virtual inertial control system based on quantization and regulation decoupling of active power increments is proposed in this paper. First, by setting the parameters of a proportional–differential (P-D) algorithm, the total active power increments required for virtual inertial response are quantified at the DFIG level. Secondly, a curve-shifting method based on the rate of change of frequency is adopted to adjust the active power output of the DFIG units. Finally, a battery energy storage system (BESS) is used to compensate for the power shortages of the units according to the quantized value of the active power increments. Simulations show that the control method can not only eliminate SFD but also effectively increase the system’s virtual inertia.

Research on the Combined Control System of Speed Regulation and Excitation for Hydrogenerator Units

Research on the Combined Control System of Speed Regulation and Excitation for Hydrogenerator Units

A design framework for combined marine propulsion control systems: From conceptualisation to sea trials validation

The ship's dynamic performance (acceleration, turning ability, crash stop) strongly depends on both the propulsion system and its control. The steady-state performance analysis of propulsion systems has shown that onboard energy usage benefits from the employment of simulation techniques. Besides, these techniques provide significant advantages in designing the control logic of sophisticated and complex systems. The present work summarizes the research activities conducted to develop suitable simulation framework for the propulsion systems of naval vessels. Theoretical and mathematical models have thus been developed in this paper to simulate the propulsion of ships. Model-scale experiments and full-scale trials have been used to increase the fidelity of the models. The research outcome is a conceptual framework and a fully validated parametric software representing the vessel's dynamic behaviour and propulsion system in steady-state and abrupt manoeuvres. Thanks to this simulation framework, the propulsion control system could be designed, validated, and calibrated before its installation on board, reducing the commissioning time and minimising the propulsion control system's onboard calibration during the acceptance sea trials.

Gust Alleviation and Wind Tunnel Test by Using Combined Feedforward Control and Feedback Control

Gust alleviation is of great significance for improving aircraft ride quality and reducing gust load. Using aircraft response (feedback control) and gust disturbance information (feedforward control) to improve the gust alleviation effect is worthy of attention. In this paper, a combined control system (CCS) composed of feedforward control system (FFCS) and feedback control system (FBCS) is designed and analyzed. At the same time, the gust alleviation effect of the CCS, the single FFCS and the single FBCS are analyzed and compared by means of numerical simulation and wind tunnel test, respectively. Taking a flexible wing as the research object, the gust alleviation effects of three control systems under different forms of gust excitation (1-cos discrete gust, sine gust and Dryden turbulence) are analyzed by numerical simulation. In the wind tunnel test, the sine gust generated by a gust generator was used, and the gust alleviation test was carried out under different wind speeds and gust frequencies. The simulation and experimental results show that the CCS has better gust alleviation performance for various gust excitations. When comparing FFCS and FBCS, the FFCS has better robustness and control effect than the FBCS. When comparing FFCS and CCS, the better the alleviation effect of FFCS, the more difficult it is to achieve significant effect improvement by using CCS, which is obtained by adding FBCS on the FFCS.

Model Reference Adaptive Control of Marine Permanent Magnet Propulsion Motor Based on Parameter Identification

Marine permanent magnet synchronous propulsion motors have problems, such as low reliability and difficult maintenance in the traditional control. In this paper, a sensorless control system for a permanent magnet synchronous motor (PMSM) based on parameter identification is proposed. According to the mathematical model of the motor in the two-phase synchronous rotating coordinate system, a model reference adaptation system (MRAS) is used to estimate the rotor speed and rotor position of the motor. Because the MRAS is highly dependent on the motor parameters, and they will change with the environment, working state, etc., the Adaline neural network is used to identify the motor parameters online, and then the model parameters in the MRAS are corrected. The simulation results show that the combined control system can reduce the estimated error of the rotor speed by about 50% compared with the traditional method, and reduces the rotor position angle estimation error by 96%. It shows that the combined system can accurately estimate the rotational speed and rotor position of the motor, and it has high identification accuracy for the motor parameters.

A cloud-edge combined control system with MPC parameter optimization for path tracking of unmanned ground vehicle

As a new carrier to carry out intelligent task, the unmanned ground vehicle (UGV) is an important component of the intelligent transportation system (ITS) in the future. Most of traditional UGV path tracking control methods are deployed in the edge-side (on-board computing platform) with restricted data, which severely limits the improvement of UGVs’ path tracking performance. Therefore, this paper proposes a novel cloud-edge combined control system with MPC parameter optimization based on cloud brain control center (CBCC) applied in future ITS, which consists of edge-side control module and cloud-side optimization module. The proposed control system can optimize control parameters iteratively in CBCC by making the utmost of big data generated by UGVs to markedly enhance the control effectiveness. In CBCC, the path tracking performance is quantitatively evaluated from the aspects of path tracking accuracy, vehicle stability, and control stability. Also, an optimization algorithm is established by using SVR theory. Based on this, the cloud-side optimization module optimizes the control parameters of the edge-side control module by collecting and processing the big data generated by UGVs while driving. Besides, the designed edge-side control module is based on MPC algorithm and innovatively introduces a compensator which obviously reduces the error caused by the inaccuracy of the prediction model. To verify the effectiveness of the proposed cloud-edge combined control system, numerous simulation experiments are carried out. The results shows that the proposed cloud-edge combined control system can improve UGV’s path tracking performance and have strong robustness at different speeds.

Ensuring information security by building combined access control and management systems

Ensuring information security by building combined access control and management systems

Combined system of extreme control of mineralized water dilution in river basins

The theory of combined systems of extreme control, which is used in technical systems, was developed and adapted in socio-ecological-economic systems. For example, river basins are such systems. A combined extreme control system has been formalized to control the dilution of mineralized mine waters in river sections. A mathematical model of the distribution of water masses and pollution in river beds from point and diffuse sources is proposed on the basis of a system of difference balance equations under the influence of stochastic uncontrolled disturbances. With regard to such conditions as adequate instrumentation, a combined control system has been developed that uses decision-making according to environmental and economic criteria based on the analysis of input and output data simultaneously, identification and tracking of the optimum in conditions of displacement under the influence of the disturbances of extreme characteristics of the system. The structural and functional diagram is represented by the open-loop diagram, the identification of which is carried out on the basis of modeling the process of water dilution in various situations at a specific object. A closed part with a recognition system as a corrector provides feedback. Formalized mathematical models of the dynamics of water masses and pollution from point and diffuse sources are of a general nature and can be used for the basins of other rivers. The extreme control system can adapt to the hydrological conditions and water quality parameters of a particular river.
 A mathematical model has been formalized for the combined extreme control of mine water dilution in the section of the Ingulets river. The water for dilution comes from a storage pond in the Svystunov gully. Regulatory actions that maintain water quality without exceeding the normative values ​​of maximum permissible discharge are determined. At the same time, water consumption for dilution is minimized. The scenario analysis of the options showed a saving of up to 30% of water resources, namely 17.5 million m3, compared to the dilution carried out in February-March 2021 according to the existing individual regulations.

Encouraging Volitional Pedaling in Functional Electrical Stimulation-Assisted Cycling Using Barrier Functions.

Stationary motorized cycling assisted by functional electrical stimulation (FES) is a popular therapy for people with movement impairments. Maximizing volitional contributions from the rider of the cycle can lead to long-term benefits like increased muscular strength and cardiovascular endurance. This paper develops a combined motor and FES control system that tasks the rider with maintaining their cadence near a target point using their own volition, while assistance or resistance is applied gradually as their cadence approaches the lower or upper boundary, respectively, of a user-defined safe range. Safety-ensuring barrier functions are used to guarantee that the rider’s cadence is constrained to the safe range, while minimal assistance is provided within the range to maximize effort by the rider. FES stimulation is applied before electric motor assistance to further increase power output from the rider. To account for uncertain dynamics, barrier function methods are combined with robust control tools from Lyapunov theory to develop controllers that guarantee safety in the worst-case. Because of the intermittent nature of FES stimulation, the closed-loop system is modeled as a hybrid system to certify that the set of states for which the cadence is in the safe range is asymptotically stable. The performance of the developed control method is demonstrated experimentally on five participants. The barrier function controller constrained the riders’ cadence in a range of 50 ± 5 RPM with an average cadence standard deviation of 1.4 RPM for a protocol where cadence with minimal variance was prioritized and used minimal assistance from the motor (4.1% of trial duration) in a separate protocol where power output from the rider was prioritized.

Nonlinear Control System for Non-Affine Undefined Plants with Output Delays

The article deals with the problem of synthesis of the control algorithms for combined nonlinear control system for one class of single-channel non-affine priory uncertain plants with state delay in the presence of permanent bounded external noises and at measuring only the plant’s output signal. As methods for solving this problem V. M. Popov’s hyperstability criterion and the conditions of L-dissipativity are used. With the help of simulation the operation quality of the obtained system at different values of the plant relative order and its parameters is shown. The results obtained in article may be useful for construction the control systems for different dynamic plants which contains input nonlinearities and state delays.