Simple Control System Research Articles

An Automatic Irrigation Control System for Soilless Culture of Lettuce

To achieve precise measurement of moisture content in the substrate and intelligent water-saving irrigation, a simple and low cost automatic irrigation control system based on ZigBee wireless network has been developed. A software with irrigation strategy was proposed based on the models of substrate wetting pattern, lettuce root zone and the evapotranspiration. The system could detect substrate moisture in real-time and irrigate automatically according to the threshold of substrate and the irrigation strategy. The average fresh weight per plant under intelligent irrigation are 16.60% and 11.37% higher than manual control irrigation at least in different growth stages in spring and summer, the average drainage rate of intelligent irrigation is 16.08% and 17.06% smaller than manual control irrigation in spring and summer, and the irrigation water use efficiency of intelligent irrigation is 68.03% and 98.61% higher than manual control irrigation in spring and summer. The results show that the system is a promising tool for scientific and rational irrigation decision.

Theoretical performance analysis of new class of Fresnel concentrated solar thermal collector based on parabolic reflectors

The main advantage of Fresnel systems is their capability to use flexible reflectors which are cheaper in comparison to glass reflectors. In this study, the effects of using parabolic reflectors instead of flat reflectors on Fresnel solar concentrator have been studied for the first time. For this new system by ray trace statistical method, local concentration ratio distribution has been determined. The new system is compared with linear Fresnel reflector (LFR). The effect of geometrical parameters, such as absorber height and reflectors width, on the concentration ratio is studied. The results have shown that using the parabolic reflectors with low curvature has a pronounced effect on the absorber pipe diameter. Comparison of the performance of linear and parabolic systems with identical parameters such as reflectors width, reflectors number and absorber pipe height showed that the absorber tube diameter in a parabolic system is smaller than the absorber tube diameter in a linear system, thus decreased rate of heat loss from the pipe surface. Comparison of the two systems under equal solar energy radiation and absorber pipe diameter showed that in parabolic system wider reflectors can be used, thus reduced number of reflectors and simpler control system.

Comparative analysis of circular RNAs between soybean cytoplasmic male-sterile line NJCMS1A and its maintainer NJCMS1B by high-throughput sequencing

BackgroundCytoplasmic male sterility (CMS) is a natural phenomenon of pollen abortion caused by the interaction between cytoplasmic genes and nuclear genes. CMS is a simple and effective pollination control system, and plays an important role in crop heterosis utilization. Circular RNAs (circRNAs) are a vital type of non-coding RNAs, which play crucial roles in microRNAs (miRNAs) function and post-transcription control. To explore the expression profile and possible functions of circRNAs in the soybean CMS line NJCMS1A and its maintainer NJCMS1B, high-throughput deep sequencing coupled with RNase R enrichment strategy was conducted.ResultsCircRNA libraries were constructed from flower buds of NJCMS1A and its maintainer NJCMS1B with three biological replicates. A total of 2867 circRNAs were identified, with 1009 circRNAs differentially expressed between NJCMS1A and NJCMS1B based on analysis of high-throughput sequencing. Of the 12 randomly selected circRNAs with different expression levels, 10 showed consistent expression patterns based on high-throughput sequencing and quantitative real-time PCR analyses. Tissue specific expression patterns were also verified with two circRNAs by quantitative real-time PCR. Most parental genes of differentially expressed circRNAs were mainly involved in biological processes such as metabolic process, biological regulation, and reproductive process. Moreover, 83 miRNAs were predicted from the differentially expressed circRNAs, some of which were strongly related to pollen development and male fertility; The functions of miRNA targets were analyzed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), and the target mRNAs were significantly enriched in signal transduction and programmed cell death. Furthermore, a total of 165 soybean circRNAs were predicted to contain at least one internal ribosome entry site (IRES) element and an open reading frame, indicating their potential to encode polypeptides or proteins.ConclusionsOur study indicated that the circRNAs might participate in the regulation of flower and pollen development, which could provide a new insight into the molecular mechanisms of CMS in soybean.

The Study on the Risk Response of Security Cyber Physical System (Focusing on Analysis of Security Access Log and Unstructured Data)

Malicious hacking is evolving continuously malicious code attacks. It needs flexible solutions such as the prevention leakage of personal information, demanding the ability of institutions to prevent high level of infringement. But, typical simple's security control system is limited by responding only to the tertiary industry equipment in the ICT field. A CPS type security system is capable of responding to the transition from ICT to AI which is should be applied. This is time of reorganization from the current security domain to the artificial intelligent ICBM device, it should apply the digital twin model which we are considering the people and environment of CPS type system. In this paper, we have studied a model of how cyber - physical systems can be implemented using existing security system platform technology. We also propose a new security technology applying model through analyzing log form of security equipment that has occurred for many years.

A co-simulation approach for heavy haul long distance locomotive-track simulation studies

ABSTRACTThe operation of heavy haul high adhesion locomotives on the long distance track from mines to ports is a subject of recent track damage studies. Such studies require the introduction of a traction power system for each locomotive running in the heavy haul train followed by consideration of the whole system developed as a complex mechatronic model. It is nowadays common to use co-simulation for the creation of mechatronic models. This paper introduces an approach which can be applicable for a whole train simulation and is based on the combination of two types of software – a multibody simulation package for the mechanical model of a heavy haul locomotive and tools for simulation of traction power systems. This paper describes the integration of a shared library, generated by means of Simulink Code Generation, in Gensys multibody software for the co-simulation process. The validation of the newly developed approach has been performed by means of the simulation of both simplified and full traction control systems for a heavy haul locomotive running on straight track with the same scenarios previously used for the existing co-simulation approach based on a TCP/IP data exchange interface. Validation of the newly developed approach has also been performed with longitudinal train dynamics considered.

Microcontroller-based Control and Data Acquisition System for a Grid-connected Renewable Energy System

There has been a significant increase in the exploitation of renewable energy systems. To be able to efficiently utilize grid - connected renewable energy sources, there must be a reliable control and monitoring system. In building a control and monitoring system for this system, a power analyzer connected to a microcontroller was used. The microcontroller was linked to touchscreen display where a graphical user interface (GUI) was programmed to able to display and log the data recovered. Relays were used to reconfigure the system by shifting the load’s source of energy between the grid and renewable energy system. The energy generated by the renewable energy system may be delivered to the load or be fed to the grid as needed. This operation will be done through either an external device or through a computer which was built to manually operate the control system and view the status of the system as determined by parameters such as cost and energy consumption. This system provided residential buildings with their own renewable energy system with a simple yet reliable control and monitoring system. The system was able to accumulate accurate and real time data. It also provided a continuous supply and switching application simultaneously.

Optimal Surface Aeration Control in Full-Scale Oxidation Ditches through Energy Consumption Analysis

Oxidation ditches are popularly used in rural areas and decentralized treatment facilities where energy deficiency is of concern. Aeration control technologies are well established for diffusion systems in order to improve energy efficiency, but there are still challenges in their application in oxidation ditches because surface aerators have unique characteristics with respect to oxygen transfer and energy consumption. In this paper, an integral energy model was proposed to include the energy, aeration, and fluidic effects of surface aerators, by which the energy for aeration of each aerator can be estimated using online data. Two types of rotating disks with different diameters (1800 mm and 1400 mm) were monitored in situ to estimate the model parameters. Furthermore, a feedforward–feedback loop control strategy was proposed using the concept of energy analysis and optimization. The simplified control system was implemented in a full-scale Orbal oxidation ditch, achieving an approximately 10% saving in full-process energy consumption. The cost–benefit analysis and carbon emission assessment confirmed the economic feasibility and environmental contribution of the control system. The energy model can help process designers and operators to better understand and optimally control the aeration process in oxidation ditches.

A phase model approach for thermostatically controlled load demand response

A significant portion of electricity consumed worldwide is used to power thermostatically controlled loads (TCLs) such as air conditioners, refrigerators, and water heaters. Because the short-term timing of operation of such systems is inconsequential as long as their long-run average power consumption is maintained, they are increasingly used in demand response (DR) programs to balance supply and demand on the power grid. Here, we present an ab initio phase model for general TCLs, and use the concept to develop a continuous oscillator model of a TCL and compute its phase response to changes in temperature and applied power. This yields a simple control system model that can be used to evaluate control policies for modulating the power consumption of aggregated loads with parameter heterogeneity and stochastic drift. We demonstrate this concept by comparing simulations of ensembles of heterogeneous loads using the continuous state model and an established hybrid state model. The developed phase model approach is a novel means of evaluating DR provision using TCLs, and is instrumental in estimating the capacity of ancillary services or DR on different time scales. We further propose a novel phase response based open-loop control policy that effectively modulates the aggregate power of a heterogeneous TCL population while maintaining load diversity and minimizing power overshoots. This is demonstrated by low-error tracking of a regulation signal by filtering it into frequency bands and using TCL sub-ensembles with duty cycles in corresponding ranges. Control policies that can maintain a uniform distribution of power consumption by aggregated heterogeneous loads will enable distribution system management (DSM) approaches that maintain stability as well as power quality, and further allow more integration of renewable energy sources.

A Load Transportation Nonlinear Control Strategy Using a Tilt-Rotor UAV

This paper proposes a nonlinear control strategy to solve the trajectory tracking problem of a tilt-rotor Unmanned Aerial Vehicle (UAV) when transporting a suspended load. For the present study, the aim of the control system is to track a desired trajectory of the aircraft with load’s swing-free, even in the presence of external disturbances, parametric uncertainties, unmodeled dynamics, and noisy position measurements with lower sampling frequency than the controller. The whole system modeling is obtained through the Euler-Lagrange formulation considering the dynamics of the tilt-rotor UAV coupled to the suspended load. As for the nonlinear control strategy, an inner-loop control is designed based on input-output feedback linearization combined with the dynamic extension approach to stabilize the attitude and altitude of the UAV assuming nonlinearities, while an outer-loop control law is designed for guiding the aircraft with reduced load swing. The linearized dynamics are controlled using linear mixed H2/H∞ controllers with pole placement constraints. The solution is compared to two simpler control systems: the first one considers the load as a disturbance to the system but does not avoid its swing; the second one is a previous academic result with a three-level cascade strategy. Finally, in order to deal with the problem of position estimation in presence of unknown disturbances and noisy measurements with low sampling frequency, a Linear Kalman Filter with Unknown Inputs is designed for estimating both the aircraft’s translational position and translational disturbances. Simulation results are carried out to corroborate the proposed control strategy.

Generalized nonisolated high step‐up DC‐DC converter with reduced voltage stress on devices

SummaryIn this paper, a nonisolated high step‐up DC‐DC converter with low voltage stress on power devices is proposed. The proposed structure consists of a switch and n stages of inductor‐capacitor‐diode cells. The proposed topology combines the boost converter with the self‐lift circuit. Increasing the number of inductor‐capacitor‐diode cells leads to higher voltage gain with a small value of the switch duty cycle, which increases the controllability of the converter. Moreover, by increasing the number of stages, the normalized voltage stress of the power devices is reduced. As a consequence, the metal‐oxide‐semiconductor field‐effect transistor switch with low RDS‐on and devices with low nominal voltage can be used in the proposed converter. Furthermore, due to the existence of one switch, the proposed converter has a simple control system. The analysis of the voltage and current stresses of the power devices is carried out. The circuit performance is compared with other proposed topologies in the literature in voltage gain and normalized voltage stress. Finally, to evaluate the performance of the proposed converter, the experimental results are provided.

Maximum power point tracking using Hill Climbing and ANFIS techniques for PV applications: A review and a novel hybrid approach

The development of Maximum Power Point Tracking (MPPT) techniques is continuing in order to increase the generated energy from photovoltaic (PV) generators. A variety of MPPT techniques have been proposed and classified based on three main categories: offline, online and hybrid techniques. This paper presents a review of the most popular techniques for offline and online tracking of the Maximum Power Point (MPP), which are the Adaptive Neuro-Fuzzy Inference System (ANFIS) and Hill Climbing (HC) techniques, respectively. This is in addition to a review for all hybrid techniques reported in the literature demonstrating their main merits and shortcomings. Moreover, the present paper combines the ANFIS and HC as a hybrid technique for the first time. The proposed technique involves the features of the ANFIS and HC techniques and mitigates their shortcomings in order to increase the generated PV electrical energy. The proposed technique is a combination of two stages to assess the duty ratio (control signal) being applied to a boost converter for MPP tracking. The first stage includes a set point calculation loop to estimate the duty ratio. The second stage involves a fine tuning loop to determine the exact duty ratio corresponding to the MPP. This achieves maximum power transfer to the load even under nonuniform climatic conditions using a relatively simple control system. The proposed technique has been simulated in MATLAB/SIMULINK environment and compared with some other MPPT techniques (the Constant Voltage (CV), ANFIS, HC, Incremental Conductance (IncCond) techniques) for steady state and rapidly changing climatic conditions (Ropp and sine radiation tests) as well as load variations. The results reveal that the proposed hybrid MPPT technique outperforms other MPPT techniques in term of performances indicators, which include the tracking speed, tracking accuracy and energy gain factor.

Wall Inspection Robot with Maneuvering Assist Control System Against Crosswind

Many social infrastructures and buildings are aging. Therefore, inspections to find deteriorated parts to prevent accidents are important. However, significant costs and inspection time are required for the current technologies. Therefore, inspection methods using robots are attracting attention. As the most appropriate option to traverse freely on concrete bridges and building walls is by traversing with lift force from propellers, a robot called HORNET has been developed that can run along a wall with two rotors. However, the floating-type robot with propellers could drop from a wall if hit by strong wind. Therefore, a gyro sensor was installed in the robot to detect its posture and adopted a simple maneuvering assist control to reduce the above-mentioned issue. In this study, the motion of HORNET was analyzed and a simple control system was designed to realize the maneuvering assist control. It was confirmed that the resistance of HORNET to the crosswind was improved by adding the control system.

A Fuzzy Probability Bayesian Network Approach for Dynamic Cybersecurity Risk Assessment in Industrial Control Systems

With the increasing deployment of data network technologies in industrial control systems (ICSs), cybersecurity becomes a challenging problem in ICSs. Dynamic cybersecurity risk assessment plays a vital role in ICS cybersecurity protection. However, it is difficult to build a risk propagation model for ICSs due to the lack of sufficient historical data. In this paper, a fuzzy probability Bayesian network (FPBN) approach is presented for dynamic risk assessment. First, an FPBN is established for analysis and prediction of the propagation of cybersecurity risks. To overcome the difficulty of limited historical data, the crisp probabilities used in standard Bayesian networks are replaced in our approach by fuzzy probabilities. Then, an approximate dynamic inference algorithm is developed for dynamic assessment of ICS cybersecurity risk. It is embedded with a noise evidence filter in order to reduce the impact from noise evidence caused by system faults. Experiments are conducted on a simplified chemical reactor control system to demonstrate the effectiveness of the presented approach.

Adaptive Flow Separation Control Over an Asymmetric Airfoil

A closed-loop adaptive flow control system was experimentally demonstrated to control the flow separation over an NACA 64A210 airfoil. To control the flow separation, piezoelectrically driven synthetic jet actuators and pressure sensors were used. Before performing the closed-loop flow separation control experiment, the effectiveness of the synthetic jet actuator was investigated by open-loop experiments for an NACA 64A210 airfoil in various operating conditions to examine the effective control parameter. The pressure gradient, which was calculated from the difference of mean pressure coefficients between two sensor positions, was found to be a criterion for flow recovery in these experiments. Therefore, the pressure gradient was selected as a control parameter for separated flow. An adaptive flow control system using adaptive inverse control and extremum-seeking control was developed to control the pressure gradient for separated flow over an NACA 64A210 airfoil. The performance of the resulting flow control system was compared with a simple PID control system. Experimental results based on the proposed adaptive flow control system demonstrated the satisfactory tracking performance of the pressure gradient for the pressure recovery. As a result, the proposed adaptive flow control approach enhanced the aerodynamics performances in terms of lift and drag coefficients and lift/drag ratio in the closed-loop control system.

Sampled-data controllability and stabilizability of Boolean control networks: Nonuniform sampling

Derived from a simplified intelligent traffic control system, sampled-data controllability and stabilizability of Boolean control networks are considered. Compared with the existing case of uniform (periodic) sampling in Boolean control networks, the nonuniform one is more general. Using linear span with integral coefficients, the distribution of sampling points can be obtained. Then by constructing novel systems, some necessary and sufficient conditions are proposed to determine sampled-data controllability and stabilizability. Finally, two illustrative examples, which are on apoptosis networks and traffic control systems, respectively, are worked out to show the effectiveness of the obtained results.

Design of portable 3-axis filament winding machine with inexpensive control system

Filament winding technology is one of the fundamental methods in composite material fields, which needs a high degree of automation. It is the process in which continuous strands or filament of fibres are wound on the mandrel, which is more suitable for making high-pressure vessels, pipes, shaft and ducts. The filament winding machines have existed in enterprises or factories, which are high costs, heavy, complex control system, simple products so far. This paper describes the development of a new 3-axis filament winding machine for the production of wound composite cylinders, which is designed to be more portable, lightweight, low costs, high efficiency and easy control system compared to previous machines. It relates to design hardware control system and the software control system. Based on three axes movement principles, a 3-axis prototype filament winding machine has been developed. The x-axis is the movement left and right of the carriage, the y-axis is the rotation of mandrel and the z-axis is the movement of the feeder. Arduino Uno and CNC (Computer Numeral Control) shield module are used as hardware of control system. Universal G-Code Sender (UGS) and Grbl (G-codes) are adopted as software control system. In conclusion, a protable 3-axis filament winding machine has been successfully designed and performed, which offers potential filament wound composite cylinders with simple control system.

Sequential induction of three recombination directionality factors directs assembly of tripartite integrative and conjugative elements.

Tripartite integrative and conjugative elements (ICE3) are a novel form of ICE that exist as three separate DNA regions integrated within the genomes of Mesorhizobium spp. Prior to conjugative transfer the three ICE3 regions of M. ciceri WSM1271 ICEMcSym1271 combine and excise to form a single circular element. This assembly requires three coordinated recombination events involving three site-specific recombinases IntS, IntG and IntM. Here, we demonstrate that three excisionases–or recombination directionality factors—RdfS, RdfG and RdfM are required for ICE3 excision. Transcriptome sequencing revealed that expression of ICE3 transfer and conjugation genes was induced by quorum sensing. Quorum sensing activated expression of rdfS, and in turn RdfS stimulated transcription of both rdfG and rdfM. Therefore, RdfS acts as a “master controller” of ICE3 assembly and excision. The dependence of all three excisive reactions on RdfS ensures that ICE3 excision occurs via a stepwise sequence of recombination events that avoids splitting the chromosome into a non-viable configuration. These discoveries expose a surprisingly simple control system guiding molecular assembly of these novel and complex mobile genetic elements and highlight the diverse and critical functions of excisionase proteins in control of horizontal gene transfer.

Semi‐Global Output Feedback Tracking to Reference System with Input for a Benchmark Nonlinear System

AbstractIn this paper, we solve the output feedback semi‐global tracking problem of the nonlinear benchmark RTAC system, in which the reference signals are output trajectories of a simple control systems subject to some input. The introduction of the input enlarges the class of the reference signals that can be tracked. And the proposed solution covers the previous results of output feedback global tracking, namely the solution is still global when the input is zero. Finally, a simulation illustrates the effectiveness of our approach.

Electrical machines-based multi-disturbance device for testing distribution grid technologies

The growth of distributed energy resources in power systems, mainly converter-coupled generators, has forced the evolution of grid codes, increasing the requirements to be fulfilled by the generators before their connection to the mains. Solving this problem is crucial to guarantee the reliability and stability of the power system. Current standards force the generators to remain connected when facing voltage and/or frequency disturbances and, in some advanced grid codes, also when the generators are facing transient phase jumps produced as a consequence of those disturbances. If considering that the increment of the distributed generation is mainly done at a distribution level, it is unrealistic to consider voltage and frequency events as decoupled phenomena in the testing and certification procedures, as it is currently done. The testing device proposed in this paper is able to reproduce voltage, frequency and phase jumps disturbances of a controlled value simultaneously, being able to reproduce the real grid behavior reliably. Its design is based on standard components with a simple control system, which makes it easily replicable and scalable up to the power of the device to be tested. Therefore, the proposed device is an interesting commercially competitive testing equipment suitable for certification.

Model and experiments to optimize co-adaptation in a simplified myoelectric control system

Objective. To compensate for a limb lost in an amputation, myoelectric prostheses use surface electromyography (EMG) from the remaining muscles to control the prosthesis. Despite considerable progress, myoelectric controls remain markedly different from the way we normally control movements, and require intense user adaptation. To overcome this, our goal is to explore concurrent machine co-adaptation techniques that are developed in the field of brain–machine interface, and that are beginning to be used in myoelectric controls. Approach. We combined a simplified myoelectric control with a perturbation for which human adaptation is well characterized and modeled, in order to explore co-adaptation settings in a principled manner. Results. First, we reproduced results obtained in a classical visuomotor rotation paradigm in our simplified myoelectric context, where we rotate the muscle pulling vectors used to reconstruct wrist force from EMG. Then, a model of human adaptation in response to directional error was used to simulate various co-adaptation settings, where perturbations and machine co-adaptation are both applied on muscle pulling vectors. These simulations established that a relatively low gain of machine co-adaptation that minimizes final errors generates slow and incomplete adaptation, while higher gains increase adaptation rate but also errors by amplifying noise. After experimental verification on real subjects, we tested a variable gain that cumulates the advantages of both, and implemented it with directionally tuned neurons similar to those used to model human adaptation. This enables machine co-adaptation to locally improve myoelectric control, and to absorb more challenging perturbations. Significance. The simplified context used here enabled to explore co-adaptation settings in both simulations and experiments, and to raise important considerations such as the need for a variable gain encoded locally. The benefits and limits of extending this approach to more complex and functional myoelectric contexts are discussed.