Popular Control Methods Research Articles

Principles and Methods of Servomotor Control: Comparative Analysis and Applications

Servomotors have found widespread application in many areas, such as manufacturing, robotics, automation, and others. Thus, the control of servomotors is divided into various principles and methods, leading to a high diversity of control systems. This article provides an overview of types of servomotors and their basic principles and control methods. Principles such as digital signal processing, feedback control principle, field-oriented control, and integration with Industry 4.0 are discussed. Based on these control principles, the article presents popular control methods: PWM control, current control, two-loop control, fuzzy-logic control, and programmable control. The article concludes with a comparison of the presented methods on several criteria, and as an example, it includes the results of modeling a servomotor using the fuzzy-logic control method.

Active Neural Network Control for a Wearable Upper Limb Rehabilitation Exoskeleton Robot Driven by Pneumatic Artificial Muscles.

Pneumatic artificial muscle (PAM) has been widely used in rehabilitation and other fields as a flexible and safe actuator. In this paper, a PAM-actuated wearable exoskeleton robot is developed for upper limb rehabilitation. However, accurate modeling and control of the PAM are difficult due to complex hysteresis. To solve this problem, this paper proposes an active neural network method for hysteresis compensation, where a neural network (NN) is utilized as the hysteresis compensator and unscented Kalman filtering is used to estimate the weights and approximation error of the NN in real time. Compared with other inversion-based methods, the NN is directly used as the hysteresis compensator without needing inversion. Additionally, the proposed method does not require pre-training of the NN since the weights can be dynamically updated. To verify the effectiveness and robustness of the proposed method, a series of experiments have been conducted on the self-built exoskeleton robot. Compared with other popular control methods, the proposed method can track the desired trajectory faster, and tracking accuracy is gradually improved through iterative learning and updating.

Emergence of Synchronous Reluctance Motor Drive for an Electric Vehicle

According to recent research, synchronous reluctance motors, or SynRMs, offer innovative and promising technology. Consequently, there has been a growth in research on popular SynRMs drive systems. Recent advances in the design, modeling, and more importantly control of these motors are disseminated in this paper. Prior to moving on to SynRMs, a quick analysis of the leading motor technology is done. In order to help industries and researchers choose the best control method for motor drive systems, the most popular motor control methods are examined and categorized in the second section. In conclusion, the various speed zones of SynRM control techniques are examined, and the changes between trajectories are examined.

Review of Fault Diagnosis and Fault-Tolerant Control Methods of the Modular Multilevel Converter Under Submodule Failure

Modular multilevel converters (MMCs) have attracted extensive research interests in various ac and dc conversion applications due to their modular structure and excellent harmonic performance. However, the large number of power switches increases the potential risk of submodule (SM) failure, which greatly challenges the safe and reliable operation of the MMC. This paper presents a detailed review of fault diagnosis and fault-tolerant control methods of the MMC under SM failures. On this basis, comprehensive comparisons are conducted among different fault diagnosis methods, and verification results are provided to analyze the advantages and disadvantages of the popular fault-tolerant control methods. Finally, the review is concluded, and future trends and research opportunities are discussed.

Towards a Controlled Orthosis for Sit-To-Stand Support in Independently Living Elderly: Model Development

Sit-to-stand (STS) movements are a daily challenge for independently living elderly. Literature shows a keen interest in using active orthoses to mitigate this problem. However, to design and test advanced control strategies for proof-of-concept orthoses, a validated model of the STS movement is missing. This work presents and elaborates on a model of the kinematics of the lower limb in combination with a human policy which represents the brain-muscle interaction. The model parameters are derived from both healthy and elderly patients. The applicability of the model is investigated by applying two popular control methods for active orthoses: gravity compensation and a control-based method. First, the results show model validation using measured in vivo joint torques from literature and, second, that both methods can be simulated using the developed STS model. This allows for optimizing and testing advanced control strategies in future work.

Error control in tree structured hypothesis testing

AbstractThis manuscript reviews some recent and popular error control methods for tree structured hypothesis testing. We review a common setting/definition for hypotheses arranged in a tree structure and we discuss two common Type I errors present in multiple testing: family wise error rates (FWERs) and false discovery rate (FDR). We also contrast these methods with a recent development designed to control the false selection rate (FSR). We discuss the algorithms used to implement these error controls and the strategies used to navigate tree structures in light of these errors. We highlight the assumptions necessary in these strategies, summarize the available R software packages to implement these approaches, and show them at work on an example.This article is categorized under: Data: Types and Structure > Image and Spatial Data Applications of Computational Statistics > Genomics/Proteomics/Genetics Data: Types and Structure > Microarrays

Comparison of synchronization of chaotic Burke-Shaw attractor with active control and integer-order and fractional-order P-C method

Many studies have been introduced in the literature showing that two identical chaotic systems can be synchronized with different initial conditions. Secure communication applications using synchronization methods are also presented in the literature. In the study, synchronization performances of two popular synchronization methods, active control and Pecaro Carroll (P-C) methods for secure communication application are compared. The Burke-Shaw chaotic attractor was synchronized with active control, integer-order and fractional-order P-C methods and their performances were compared. Both synchronization methods are modeled in Matlab™ environment. In both synchronization methods, it is shown with error graphs that the two systems are synchronized. Experimental results showed that the P-C method with optimal fractional value synchronized in 2.3 (time units) shorter than the active control method. The shortening of the synchronization time ensures that the synchronization is faster in secure communication applications, allowing the transmitted signal to reach the receiver faster from the sender. It shows that the P-C method with optimal fractional-order creates a lower delay in the synchronization time and is more suitable for use in secure communication applications. In addition, a secure communication application was made with the method proposed in the study and it was shown that the system could be used in secure communication applications.

Disturbance observer based inverse optimal control for a class of nonlinear systems

In this paper, we propose an inverse optimal composite control (IOCC) method to solve the optimization problem for a class of high-dimensional nonlinear strict-feedback systems with disturbances. Initially, we give these systems an inverse optimal control framework that avoids solving Hamilton–Jacobi-Bellman equations. Then, a nonlinear disturbance observer is designed to estimate the disturbances in the systems. We incorporate these disturbance estimates into the virtual control law design through a backstepping method that gives us a control Lyapunov function. In the end, this control Lyapunov function is utilized to obtain a composite controller that achieves optimality and disturbance rejection. We provide rigorous proofs for the convergence of the proposed composite controller. Simulation studies and comparative results from a real-life application to single-link robots show that the proposed composite controller achieves more robustness and effectiveness than the popular control methods in high-dimensional nonlinear systems.

Weakened PAM/PEI Polymer Gel for Oilfield Water Control: Remedy with Silica Nanoparticles.

Polymer gel treatment is one of the most popular conformance control methods used in the petroleum industry. The advantage of the polymer gel system used in harsh reservoir conditions is an integrated process that must take into account all elements of gelation kinetics. In high-temperature applications, NH4Cl has been selected as a retarder to extend the gelation time of a PAM/PEI gel system. However, the gel network loses gel strength when salt and retarder increase, resulting in a weak gel structure, and becomes susceptible. The combination of these two variables leads to the development of a weak gel network, making it fragile and susceptible. To strengthen the weakened PAM/PEI polymer gel, the addition of silica nanoparticles (silica NP) is considered an effective remedy. This article presents the performance of PAM/PEI polymer gel strengthened with silica NP, especially the performance in terms of viscosity, gelation time, and gel strength, as well as performance in porous media. For example, the results exhibited a high storage modulus, G′, which is almost 800 Pa, compared to the loss modulus, G″, throughout the frequency and strain range, indicating solid-like behavior, at significantly high amounts of silica NP. This finding provides a better understanding and knowledge on the influence of solid particles in enhancing the performance of PAM/PEI polymer gel that has been weakened by salinity and retarder.

A Study on Vision-Based Backstepping Control for a Target Tracking System

This paper proposes a new method to control the pose of a camera mounted on a two-axis gimbal system for visual servoing applications. In these applications, the camera should be stable while its line-of-sight points at a target located within the camera’s field of view. One of the most challenging aspects of these systems is the coupling in the gimbal kinematics as well as the imaging geometry. Such factors must be considered in the control system design process to achieve better control performances. The novelty of this study is that the couplings in both mechanism’s kinematics and imaging geometry are decoupled simultaneously by a new technique, so popular control methods can be easily implemented, and good tracking performances are obtained. The proposed control configuration includes a calculation of the gimbal’s desired motion taking into account the coupling influence, and a control law derived by the backstepping procedure. Simulation and experimental studies were conducted, and their results validate the efficiency of the proposed control system. Moreover, comparison studies are conducted between the proposed control scheme, the image-based pointing control, and the decoupled control. This proves the superiority of the proposed approach that requires fewer measurements and results in smoother transient responses.

Seamless mode‐switching control for electric spring with capacitor DC bank

Electric spring (ES) has been proposed to suppress the fluctuations of critical load voltage under the condition of the increasing proportion of renewable energy in the power grid, but existing popular control methods have not fully released its application potential. Therefore, a novel control strategy that enables it to operate in the entire scope is proposed in this study, which differs from the conventional methods since the fully known of all system parameters is not indispensable. Furthermore, a seamless operating mode switching method is discussed, which is important for practical application. In the end, the simulation results in PSCAD/EMTDC verify that the ES can operate stably in various regions, and can seamlessly switch between capacitive and inductive modes.

Benchmarking Australian sheep parasite control practices: a national online survey

Context The third Australian national survey on control practices for internal and external parasites of sheep, following similar surveys in 2003 and 2011. Aims To document current parasite control practices and attitudes, measure change and to provide a benchmark against which to assess future practices and attitudes. Methods An online survey emailed to 6460 sheep producers, with a paper version supplied on request. A follow up short survey was conducted to assess non-response bias. Analysis by region and key sheep enterprise. Key results There were 354 and 250 useable responses to the main and short surveys respectively. Mean reported rainfall of 407 mm in 2018 was 27% lower than the average for respondents and >200 mm lower than mean reported rainfall in the previous surveys. The top three methods for worm control over the past 5 years were preventative treatments (74%), preparing clean pastures by spelling paddocks (62%) and treatment on the basis of faecal worm egg count (WEC, 54%). The proportion of respondents using WEC monitoring in 2018 was 40.4%, with a mean frequency of 3.1/year, and this was unaffected by sheep class. The frequency of anthelmintic treatment for ewes and lambs and weaners was 2.1/year. Of the respondents, 36.7% had performed an anthelmintic resistance test in the previous 5 years. The most popular flystrike control methods were timing of crutching (76.4%), preventative chemical treatment (75.9%), timing of shearing (63.1%), mulesing (46.8%) and genetic selection (46.4%). Pain relief was widely used for mulesing ewes (86.6%) and wethers (90.9%). Only 17.3% used Australian Sheep Breeding Values for traits in rams. Most respondents reported ‘evidence of lice’ in the past 5 years (55.8%) and had treated for lice off shears (50.1%), short wool (16.6%) or long wool (6.6%), with only 26.7% having not treated at all in the period. Web-based sources of information on parasite control have become increasingly important. Conclusions Notable changes since the earlier surveys were high rates of pain relief when mulesing, an increase in the use of Australian Sheep Breeding Values for parasite-related traits, an increase in WEC monitoring since 2011 and an increased use of web-based resources. Implications Parasite control remains important for sheep producers and continues to evolve with new drugs and approaches. The surveys highlight the effectiveness of extension networks and identify where more attention is required.

Evaluating Optimization Objectives in Linear Quadratic Control Applied to Open Canal Automation

AbstractProportional-integral (PI) control, as one of the most popular classic control methods, has been applied widely to the real-world practice of canal automatic control. The performance of a P...

Q-learning optimized diagonal recurrent neural network control strategy for brushless direct current motors

In order to improve the working stability of brushless direct current motors (BLDCM), a diagonal recursive neural network (DRNN) control strategy based on Q-learning algorithm is proposed in this paper which is called as Q-DRNN. In Q-DRNN, DRNN iterates over the output variables through a unique recursive loop in the hidden layer, and its key weight is optimized to speed up the iteration. Moreover, an improved Q-learning algorithm is introduced to modify the weight momentum factor of DRNN, which makes DRNN have the ability of learning and online correction so as to make the BLDCM achieve better control effect. In MATLAB/Simulink environment, Q-DRNN is tested and compared with other popular control methods in terms of speed and torque response under different operating conditions, and the results show that Q-DRNN has better adaptive and anti-interference ability as well as stronger robustness.

Design of Smart Battery Management System for Electric Vehicle

The Battery is the most basic part of the Electric Vehicle, which serves as a major source of energy and gives it sustainable mobility. In electric vehicles, the technology that is highly recognized and used for energy storage is based on lithium chemistry. Nevertheless, the room for research is still open. This involves the collection of materials for the development of cells. The development of algorithms and the design of electronic circuits for a better and more efficient use of batteries is also one area of study. It is important to keep an eye on the critical operating parameters of the battery during charging for the optimum output of the batteries. A battery management system (BMS) is one of those mechanisms for monitoring internal and ambient battery temperature, current, voltage, and charging and discharge operations. Within this paper we speak about some of the popular battery control methods and framework. We also speak about the state-of-the-art device criteria for optimum battery efficiency and its general architecture.

Feedforward model-inverse position control of three-stage servo-valve using zero magnitude error tracking control

Three-stage servo-valves are popularly used in hydraulic systems that require large flow rate and high pressure. For a proper control of flow direction and flow rate fed into a hydraulic actuator, securing a proper position control bandwidth is a critical task for the servo-valve. In this paper, a set of popular control methods are systematically studied and a control method is selected. It is proven that the feedforward model-inverse control is the most effective method in terms of the control bandwidth. In the present work, the feedforward closed-loop architecture is adopted and the closed-loop system is estimated in a linear discrete-time transfer function by recursive least squares method. On recognizing a nonminimum phase zero problem, this work implements the zero magnitude error tracking control, an approximate model-inverse technique, in order to overcome the problem. As a result, the effectiveness of the proposed feedforward model-inverse position control strategy is verified.

Model‐Based ILC with a Modified Q‐Filter for Complex Motion Systems: Practical Considerations and Experimental Verification on a Wafer Stage

Iterative learning control (ILC) is one of the most popular tracking control methods for systems that repeatedly execute the same task. A system model is usually used in the analysis and design of ILC. Model‐based ILC results in general in fast convergence and good performance. However, the model uncertainties and nonrepetitive disturbances hamper its practical applications. One of the commonly used solutions is the introduction of a low‐pass filter, namely, the Q‐filter. However, it is indicated in this paper that the existing Q‐filter configurations compromise the servo performance, although improving the robustness. Motivated by the combination of performance and robustness, a novel Q‐filter configuration in ILC is presented in this paper. Some practical considerations, such as the configuration of ILC in a feedback control system, the time delay compensation, and the learning coefficient, are provided in the implementation of the proposed ILC algorithm. The effectiveness and superiority of the proposed ILC versus existing Q‐filter ILC are demonstrated by both theoretical analysis and experimental verification on a wafer stage.

New Efficient Submodule for a Modular Multilevel Converter in Multiterminal HVDC Networks

In high-voltage applications, the magnitude of total semiconductor losses (on-state and switching) determines the viability of modular-type multilevel converters. Therefore, this paper presents a new cell arrangement that aims to lower total semiconductor loss of the modular multilevel converter (MMC) to less than that of the half-bridge modular multilevel converter (HB-MMC). Additional attributes of the proposed cell are: it eliminates the protective thyristors used in conventional half-bridge cells that deviate part of the dc-fault current away from the antiparallel diode of the main switch when the converter is blocked during a dc short-circuit fault, and it can facilitate continued operation of the MMC during cell failures without the need for a mechanical bypass switch. Thus, the MMC that uses the proposed cell retains all advantages of the HB-MMC such as full modularity of the power circuit and internal fault management. The claimed attributes of the proposed cell are verified using illustrative simulations and reduced scale experimentations. Additionally, this paper provides brief and critical discussions that highlight the attributes and limitations of popular MMC control methods and different MMC cells structures proposed in the literature, considering the power electronic system perspective.

Reducing seed-densities in rice seedbeds improves the cultural control of apple snail damage

Several cultural methods are known to reduce the densities of exotic apple snails (Pomacea spp.) and the damage they cause to rice in Asia. However, one aspect of seedling production – seedbed seed-density – has been largely overlooked and could compromise popular cultural control methods such as delayed transplanting. We conducted experiments to examine the effects of seedbed seed-density on hill survival in snail-infested paddy fields in the Philippines and to examine the interactions between seedbed seed-density and other cultural methods (delayed transplanting, 3 seedlings per hill and hand-picking). Seedbed seed-density determined seedling weight and stem thickness at the time of transplanting. Hill survival was highest where cultural methods (delayed transplanting and 3 seedlings per hill) were combined with low seed-density seedbeds (60–120 g m−2). Furthermore, reduced seedbed seed-density was directly related to increased hill biomass in field plots 32 days after transplanting. Hand-picking of snails together with delayed transplanting and 3 seedlings per hill eliminated hill mortality due to snail herbivory. Farmers adopting cultural snail control methods, but without adhering to low seedbed seed-densities risk increased losses due to snails because of poor quality seedlings. We suggest that seedbed seed-densities should not exceed 120 g m−2 with better results at even lower densities.

Energy Efficient and High Speed Error Control Scheme for Real Time Wireless Sensor Networks

Reliability and energy consumption are two of the main constraints in wireless sensor networks (WSNs). In this paper, a novel energy efficient and high speed error control scheme is introduced that is based on the Redundant Residue Number System (RRNS) allowing real-time application of WSNs. The proposed approach employs a new 3-moduli set [Formula: see text] and an efficient reverse converter which relies on the Mixed Radix Conversion (MRC) algorithm and achieves significant improvements both in terms of conversion delay and hardware design. In order to obtain error controllability, two-redundant-moduli set [Formula: see text] is also added to the main 3-moduli set. The theoretical results backed by simulation tests confirm that the solution put forward in this paper outperforms popular error control methods for WSNs in terms of error controllability, energy efficiency, and reduction of end-to-end delay.