External Disturbance Factors Research Articles

Assessment of factors causing landslides using the Analytical Hierarchy Process (AHP) method

Landslides are Indonesia's second most common disaster in the last ten years. Landslides cause losses, reaching hundreds of billions and threatening human safety. For this reason, it is necessary to take action to reduce the negative impact of landslides. Physical and non-physical mitigation can occur before, during, and after a disaster. The most essential thing in disaster mitigation is knowing the major factors that cause landslides. This research aims to analyze the major and minor factors that cause landslides using the Analytical Hierarchy Process (AHP) and the Likert scale. Respondents in this research are experts in disasters, especially landslides—respondents from universities in Indonesia, practitioners, and people involved in disaster mitigation. Validity and reliability tests were carried out on each question used in the questionnaire. The research results show that the landslide disaster was caused by a disruption in balance that occurred due to internal and external disturbance factors. The major external factors that cause slope failures are the cutting of hills and changes in land use to built-up areas. In contrast, the major internal factors that trigger landslides are heavy rainfall and steep topographic conditions. The results of this research in the form of weight and scoring values for each factor causing landslides can be used as a reference for mapping landslide areas to identify areas with the potential for landslides.

Research on military-civilian collaborative innovation of science and technology based on a stochastic differential game model.

The construction of an integrated national strategic system and capability is an essential goal of implementing the strategy of military-civilian integration in the contemporary era. And the collaborative innovation of military-civilian S&T is an inevitable choice to achieve this goal. Due to the dynamic, complex, and stochastic characteristics of military-civilian S&T collaborative innovation, the level of S&T innovation is highly volatile. This paper takes the internal and external stochastic disturbance factors of military-civilian S&T collaborative innovation as the perspective, studies the strategy selection problem of military-civilian S&T collaborative innovation under military domination, constructs a differential game model to explore the innovation strategies under the non-cooperative model without military subsidies, the non-cooperative model with military subsidies, and the collaborative model. Finally, we use numerical experiments to verify the validity of the conclusions. The study shows that: (1) Within a reasonable range of values of the benefit distribution coefficient, the system can achieve the Pareto optimum, and the collaborative model is conducive to improving the S&T innovation level and the optimum benefit level of the system. (2) Military subsidies can increase the benefits of the system and the parties involved to achieve Pareto improvement. (3) The level of S&T innovation under the collaborative model has dynamic evolutionary characteristics of maximum expectation and variance. As the intensity of disturbance increases, the stability of the system may be destroyed. Risk-averse civil enterprises prefer the cooperative mode, whereas risk-averse civil enterprises prefer the non-cooperative model.

Development of a fuzzy controller for adaptive control of the adsorption process

In this paper presents the development of a fuzzy controller for adaptive control of the parameters of the activated carbon adsorption process. The main objective of the developed control system is to increase the efficiency of the control of the technological process of adsorption by using intelligent technologies. It should be noted that the methodological basis for the design of fuzzy controllers is the concept of fuzzy logic. Also, for the development of fuzzy controllers for an adaptive control system, a model of the absorption process in the adsorber is constructed, taking into account multiple relationships between the parameters of the technological process. The conceptual model of the control object was developed taking into account the inherent internal relationships between the parameters of the technological regime and external disturbing factors. That is, fuzzy adaptive control allows you to adapt to changes in the technological parameters of the adsorption process by changing the control algorithm of the technological process. The expediency of using for adaptive control of technological parameters of the adsorption process by using fuzzy controllers is substantiated. The development of an adaptive control system based on fuzzy controllers was carried out using MatLab software, where a control model of the adsorption technological process was built, and the results were obtained and analyzed. Thus, fuzzy controllers evaluate critical situations and also regulate the parameters of the adsorption process based on logical rules. Keywords: adsorption; activated carbon; ethanol; fuzzy controller; system control; process parameters; adaptive control; fuzzy logic.

Blood Glucose Control on Diabetic Patient Type I using Sliding Mode Adaptive Control

Diabetes is a metabolic disorder due to insufficient insulin synthesis or inadequate insulin sensitivity. The Bergman’s minimal model describes the dynamics of blood glucose levels in type 1 diabetics. The model has control inputs in the form of insulin injections and covers external disturbance factors in the form of meal disturbances. This research developed a control design using an sliding mode adaptive control to reduce blood glucose levels in hyperglycemic patients and keep it within normal glucose levels. Sliding mode adaptive control is an adaptive controller updates the model based on measured performance while in operation. A numerical simulation of the proposed controller is carried out by giving eating disorders three times, namely at breakfast, lunch, and dinner. Based on the numerical simulation, to lower the high blood glucose in the hyperglicemic patient, the insulin injection should be given starting at 30 minutes before breakfast for the next four hour, with a maximal dose of injection is 13 mU/min. It can decrease the high blood pressure until 54.83%.

Experimental study on the collapse evolution law of unlined tunnel in Boulder-Cobble mixed formation

The construction of shallow tunnels has become increasingly challenging due to the complex geological conditions encountered, particularly in boulder-cobble mixed (BCM) formations found in river terraces. To understand the deformation characteristics of these formations, it is necessary to study the instability and failure evolution process of unlined tunnels in BCM formations. This research systematically investigates the failure evolution process and the variation laws of surrounding rock stress and displacement through a physical model test under 1 g conditions, focusing on the two most common external disturbance factors: excavation and rainfall. The study findings reveal a grouped pattern of movement in the collapsing movement. During the evolution process of instability, the surrounding rocks formed pressure arches multiple times, resulting in a clear development of staged deformation. The instability of the pressure arch zone leads to an expansion of the loose zone in the surrounding rocks, particularly in the tunnel vault area. To prevent the collapse of surrounding rocks effectively, it is suggested to control the stability of the first-formed pressure arch. Based on the instability evolution characteristics of the surrounding rock, strategies for preventing and controlling collapse are summarized and refined. Finally, a practical project is presented to demonstrate the positive impact of optimizing the excavation method and support system. The conclusions of this research have guiding significance for the prevention and control of tunnel collapse in BCM formations.

Research of energy characteristics and fault position detection for cracked rotor system

Early crack faults will introduce subtle local changes in the whole rotor system, which may bring difficulties to the fault detection process due to external disturbing factors. Meanwhile, judging the damaged position of rotor systems might be tough only through displacement or velocity. To overcome these issues, the harmonic balance-energy power flow analysis (HB-EPFA) is presented to investigate the rotor system with a transverse crack. Besides, a novel indicator (Time-averaged power flow) is proposed to evaluate the crack faults. For the energy characteristic analysis, the cracked rotor appears a special amplitude-jumping phenomenon, even in the case of shallow crack depth. The influence of crack depth on power flow values under different rotating speeds is obtained. Furthermore, the existence of cracks will lead to the rotation shaft presenting an abrupt energy-changing zone, which can be used to detect crack position. Relevant experiments are applied to validate the proposed detection method, and the experimental results agree with the theoretical analysis. The conclusions achieved in this paper can provide a reference for fault diagnosis of rotor systems in engineering practice.

An EPCH Control Strategy for Complex Nonlinear Systems with Actuator Saturation and Disturbances

This paper presents a novel error port-controlled Hamiltonian (EPCH) strategy with adaptive gains for a class of complex nonlinear systems subject to actuator saturation and disturbances. Considering the actuator saturation phenomenon in real complex systems, a new smooth saturation function with hyperbolic tangent is adopted to deal with the limitations between the actuator and the control signal. A nonlinear disturbance observer (NDOB) is utilized to compensate the influence of model parameter uncertain, noise, measurement error, external disturbance and other factors in real complex systems. To enhance the accuracy of position control and tracking control for the target, we propose a novel EPCH strategy, which adopts adaptive gain and variable damping technology in the damping injection link. Finally, the permanent magnet synchronous motor (PMSM) servo system is applied to verify the proposed method. The strategy proposed compared with port-controlled Hamiltonian based on disturbance observer, port-controlled Hamiltonian based on load torque estimator and other methods has better control performances by simulation results.

БИОЛОГИЧЕСКИЕ ЭФФЕКТЫ И ПЕРСПЕКТИВЫ И СПОЛЬЗОВАНИЯ ПРИРОДНЫХ ЦЕОЛИТОВ (ОБЗОР ЛИТЕРАТУРЫ)

The data presented in the review are devoted to the biological eff ects of natural zeolites, considered from the point of view of their use as a means of nonspecifi c protection of the body from external disturbing factors and substantiation of the need for further study of the mechanisms of action in order to use them in other branches of life.

Evaluation of Urea Cycle Activity by Metabolic Flux Analysis Using Mass Spectrometry.

Hepatocytes play an important role in maintaining homeostasis in living organisms by carrying out various metabolic functions. The urea cycle, one of the metabolic pathways taking place in hepatocytes, is an important metabolic pathway that converts toxic ammonia to nontoxic urea. Performing quantitative assessments of individual metabolite levels using a mass spectrometer is useful for assessing the metabolic state of the urea cycle in hepatocytes. In addition, metabolic flux analysis using stable isotopes and a mass spectrometer is a new technique for measuring the metabolic state. It enables conducting specific, objective, and quantitative measurement of the activated state of the target metabolic pathway regardless of external disturbing factors. This section describes the technical background and methodology of performing metabolic flux analysis of the urea cycle by mass spectrometry.

Attitude stability control of micro-nano satellite orbit maneuver based on bias momentum

In this paper, an attitude stability control strategy based on cold air micro propulsion microsatellite orbital maneuver is designed. Firstly, the influence of environmental disturbance moment, uncertainty of rotational moment of inertia and thrust eccentricity moment on the attitude stability of the micro-nano-satellite is considered, and the attitude dynamics model of the micro-nano-satellite based on biased momentum wheel and magnetic moment device is established. Then, the disturbance moments such as environmental disturbance moments, rotational inertia uncertainty and thrust eccentricity moments are analyzed. In order to suppress the influence of various internal and external disturbance factors on the stability of the micro-nano-satellite during the deorbiting process, a robust adaptive sliding mode variable structure controller is designed. The designed robust adaptive sliding mode controller is able to compensate for various disturbances adaptively. The robust adaptive sliding-mode variable structure controller is designed with a reasonable distribution of torque considering the characteristics of bias momentum wheel control and magnetic control. Finally, numerical simulations are performed, and the simulation results show that the system has good robustness.

Study on support time of tunnel lining based on non-equilibrium evolution

According to non-equilibrium evolution stability and control theory, over force is the internal effective driving force of unrecoverable time-dependent deformation. The distribution of over force reflects the failure position and mode of tunnel. The opposite force of over force is the optimal reinforcement force to prevent unrecoverable time-dependent deformation and provides a quantitative and accurate reinforcement design method for tunnel. The plastic complementary energy (PCE) is the norm of over force. The curve of PCE versus time provides a unified quantitative criterion of real time dynamic stability evaluation of tunnel in time-dependent deformation process under various external disturbing factors. Based on the curve of PCE versus time, the stresses of lining structure in different supporting time after excavation are studied comparatively. The results show that the stress of lining structure will be very high if supporting time is too early. The surrounding rock of tunnel will be unstable due to damage evolution if supporting time is too late. There is an optimal supporting time when the stress of lining structure will not be too high and the surrounding rock will not lose stability. The curve of PCE versus time can be used to guide reinforcement design and evaluate reinforcement effect.

Influence of External Factors on Airborne Missile’s Horizontal Backward Launching

This paper studies the influence of different external disturbance factors on the horizontal backward separation of airborne missiles on large transport aircraft. The method of comparison with experiment was adopted to verify the accuracy of the finite element model during the ejection process. By comparing the finite element model, it was confirmed that the all rigid body model and partly rigid body model are inaccurate in calculating the pitch angle and pitch velocity of the missile separation. Finally, the influences of ejection force, random vibration, and missile loading position on the ejection process are analyzed. The analysis found that the ejection force and the sliding distance will increase the vibration of the launching platform, therefore increase the separation pitch angle and the pitch velocity of the missile, but the influence of random vibration on platform is much greater than the other two factors, and it will also introduce randomness into the movement of the missile.

Predicting the Population Growth and Structure of China Based on Grey Fractional-Order Models

Scientific prediction and accurate grasp of the future trend of population change are conducive to the formulation of different population policies at different stages, so as to alleviate the adverse effects of the aging population on society and provide scientific theoretical reference for controlling the population size and making policy. Considering that the population system is affected by many complex factors and the structural relationship among these factors is complex, it can be regarded as a typical dynamic grey system. In this paper, the fractional-order GM (1, 1) model and the fractional-order Verhulst model are established, respectively, based on the statistical data of China's population indices from 2015 to 2019 to forecast the population size and the change trend of population structure of China from 2015 to 2050 in the short-term and medium- to long-term. The forecast results show that China’s population will grow in an inverse S shape from 2015 to 2050, when the total population will reach 1.43 billion. Moreover, during this period, the birth rate and natural growth rate of population will decrease year by year, and the proportion of aging population and the dependency ratio of population will increase year by year. Besides, the problem of aging population is going to become increasingly serious. The application of grey system method to population prediction can mine the complex information contained in the population number series. Meanwhile, the fractional-order accumulation can weaken the randomness of the original data series and reduce the influence of external disturbance factors, so it is a simple and effective population prediction method.

A lateral control strategy for unmanned ground vehicles with model predictive control and active disturbance rejection control

This paper presents a lateral control strategy with kinematic state error model-based predictive control and extended state observer for unmanned ground vehicles. Firstly, we propose a circular arc prediction technique to calculate the state of the reference system. Then, inspired by the idea of active disturbance rejection control, an extended state observer is utilized to estimate the value of the total disturbance caused by modeling uncertainties, external disturbance, and other factors in order to compensate model error. Finally, we propose a lateral controller that combines model-based prediction with extended state observer through state feedback to achieve precise trajectory tracking. The performance of the proposed control strategy is demonstrated by a co-simulation between CarSim and MATLAB/Simulink.

Continuous Fast Terminal Sliding Mode Control of Permanent Magnet Linear Synchronous Motor

The permanent magnet linear synchronous motor(PMLSM) with direct driving method, which can obtain faster speed and acceleration, has been widely used in the industrial field in recent years. However, due to the lack of transmission links and the influence of nonlinear factors, the control of PMLSM is more difficult. In order to solve the problem that the control system is easy to be affected by nonlinear friction, external disturbance and other uncertain factors, the mathematical model of PMLSM with uncertain factors is established, and a continuous fast terminal sliding mode control(TSMC) method is proposed in this paper. The exponential reaching law(ERL) is used in this method to make the motion track reach the sliding surface quickly and effectively weaken the chattering of the system. The singular problem in the fast TSMC is solved by selecting the parameters to ensure the robustness of the system and improve the response speed of the system. The simulation results show that the continuous fast TSMC method has the ability of accurate position tracking and fast response of the system, so it has great practical value.

Decentralized Fault Detection and Fault-Tolerant Control for Nonlinear Interconnected Systems

The nonlinear interconnected system is a complex and important system in daily production and life in general. Due to the interconnection influence between subsystems and external disturbance factors, the system is prone to failure. For this kind of system, a decentralized fault detection and fault tolerant control method is proposed here. Compared with the traditional control scheme, this paper designs a subsystem communication protocol to reduce the information exchange between subsystems. Based on this communication protocol, a fault detection scheme is then designed. Due to the existence of a fault detection threshold in this scheme, the system can detect the fault in time without missing it or having a false alarm. Under the assumed condition, the adaptive control rate is obtained by establishing the adaptive approximation model to approximate the upper bound of the fault, and the subsystem adaptively adjusts the control rate according to the fault condition, so that the system can quickly recover to stability. Finally, a simulation program is used to verify the proposed method.

Определение рациональных электрических режимов промышленных дуговых сталеплавильных печей

The choice of a rational electrical mode of existing or newly commissioned electric arc furnaces (EAFs) is a very difficult task for process engineers in view of the influence of external disturbing factors. Based on an electric arc heat-transfer model (EAHTM), a method is proposed, using which the problem of determining the optimal electrical operation mode can be solved with the minimal number of simplifications and assumptions, and with taking into account the specific features of a particular EAF. In solving the problem, the following factors are taken into account: the arc heat transfer conditions in the melting space; the influence of the thermal operation conditions of the electrodes and the arc length on the structure of heat fluxes during the heating by arcs, and the effect the chemical composition of the working medium has on the thermophysical properties of the arc column plasma. The radiation from EAF arcs with taking into account the column temperature profile is calculated using the method of universal arc characteristics based on the solution of a system of nonlinear algebraic equations of the EAHTM column cylindrical model. The arc length calculation is based on the EAHTM structural characteristics method and consists of comparing the arc voltage value calculated using the furnace equivalent circuit equation and the arc voltage calculated using the EAHTM. Knowing the arc length, it is possible to calculate the arc radiation power in the EAF melting space. The choice of an electrical operation mode implies specifying an electrical parameter to be maintained by the controller for a certain period of melting. The value of this parameter (arc current or the EAF phase loop impedance) governs the other electrical parameters of the electric furnace installation, such as arc power, electrical losses, power factors, efficiency, etc. In addition, the correct choice of the electrical operation mode has an influence on other important operational characteristics, such as the specific consumption of electrodes, the duration of the interval between repairs, etc.

Development of a control system for a rectification column with a neural network adjustment of the flag liquid flow and upper temperature

The gas and oil industries are high-tech industries that are based on modern advances in science and technology. This contributed to the development of the control system and the increase in the level of automation of the oil refining process. At a refinery, which is complex production, a process control system plays a key role. There is a need to provide continuous and error-free control, safe and stable operation of the system. One of the perspectives in control systems is neural networks. They can implement any desired process of a non-linear control algorithm with an incomplete, inaccurate description of the control object, and also provide easily implemented adaptation with unstable statistics. This article presents the development of a control system with a neural network adjustment of the reflux fluid flow rate and the top temperature of the column and a comparison with the number of deviations from the norm of the process parameters under the control of the neuroregulator and under the control of the PID controller. Block diagrams of a control system with a neural network controller and a PID controller are compiled. The expediency of using a neural network controller to control the object is substantiated. A mathematical model of the control object was developed taking into account its inherent internal relationships between the parameters of the technological mode and taking into account the influence of external disturbing factors. Processing of the research results was carried out using the software package “MatLab”.

Modelling the power system of a resistance welding machine electrical complex

The article has investigated the operation of the electrical complex of a resistance welding machine with thyristor current regulation. The model of the resistance welding process is presented as a control object with known input parameters, output parameters and external disturbances. The input parameters are the following: the preset welding current, a mode parameter (hard, soft), the prearranged welding time, the preset compression force, etc. The output parameters related to welding quality are the following: welding current, electrodes voltage, welding energy, resistance of the section «electrode-the part-electrode». The output parameters related to the indicators of ensuring electromagnetic compatibility of the electrotechnical complex with the electrical network are the following: the current consumed from the electrical network, reactive power consumed from the network, PF (power factor), THDI (current’s total harmonic distortion), load asymmetry coefficient. The external disturbing factors, the effect of which leads to the deterioration of the quality of welded joints are the following: fluctuations of the supply voltage, change of resistance of the welding circuit caused by the ferromagnetic masses, change of the welding circuit resistance due to its heating and/or wear, wear of the electrodes, change of the state of the welding parts surfaces, welding current bypass. The influence of disturbing factors on the welding process has been analyzed and it has been confirmed that in order to ensure a high-quality welded joint, it is necessary to stabilize the energy released in the welding contact. A model has been developed that simulates a change in the resistance of the welding circuit during the welding cycle. A model of the energy stabilization subsystem has been developed; it calculates the energy that is released in the welding contact and, when it reaches the preset value, the machine is turned off. To calculate the required energy, the heat balance equation was used, that takes into account both the useful energy, spent on the creation of the welded joint and the energy losses due to heat removal to the electrodes, to the welded parts, and convective heat transfer (which is usually neglected). The obtained results of the useful energy calculation take into account the latent heat of fusion. As a result of the simulation, it has been shown that the release of the necessary amount of energy, given welding current, results in an increase in the welding duration: taking into account the changes in resistance during welding, the welding duration grows up to 20%, taking into account the voltage fluctuations (-15%) the welding duration grows up to 30%. Under the influence of both disturbing factors, the welding duration can increase up to 60%, provided that the necessary welding quality is ensured. Thus, it has been shown that besides the magnitude of the welding current, it is possible to adjust the duration of welding, providing the necessary energy in the welding contact (taking into account the restrictions on the duration of current)

H∞ Control Design of Power System Based on Generalized Model

The generalized model power system is a complex interconnected system with complex structure and many external disturbance factors, which makes the stability of the system difficult to control. In order to guarantee the stability of the generalized model power system under the condition of external disturbance, more and more effective stability controller design methods are sought. Based on ricarty method and LMI method, the design conditions of H ∞ controller for the generalized power system composed of N subsystems are studied. At the same time, it also provides an effective way and method for analyzing the stability of similar systems.