Agricultural and forestry biomass can be converted to biochar through pyrolysis gasification,making it a significant carbon source for soil.Applying biochar to soil is a carbon-negative process that helps combat clima...Agricultural and forestry biomass can be converted to biochar through pyrolysis gasification,making it a significant carbon source for soil.Applying biochar to soil is a carbon-negative process that helps combat climate change,sustain soil biodiversity,and regulate water cycling.However,quantifying soil carbon content conventionally is time-consuming,labor-intensive,imprecise,and expensive,making it difficult to accurately measure in-field soil carbon’s effect on storage water and nutrients.To address this challenge,this paper for the first time,reports on extensive lab tests demonstrating non-intrusive methods for sensing soil carbon and related smart biochar applications,such as differentiating between biochar types from various biomass feedstock species,monitoring soil moisture,and biochar water retention capacity using portable microwave and millimeter wave sensors,and machine learning.These methods can be scaled up by deploying the sensor in-field on a mobility platform,either ground or aerial.The paper provides details on the materials,methods,machine learning workflow,and results of our investigations.The significance of this work lays the foundation for assessing carbon-negative technology applications,such as soil carbon content accounting.We validated our quantification method using supervised machine learning algorithms by collecting real soil mixed with known biochar contents in the field.The results show that the millimeter wave sensor achieves high sensing accuracy(up to 100%)with proper classifiers selected and outperforms the microwave sensor by approximately 10%–15%accuracy in sensing soil carbon content.展开更多
The bearing weak fault feature extraction is crucial to mechanical fault diagnosis and machine condition monitoring.Envelope analysis based on Hilbert transform has been widely used in bearing fault feature extraction...The bearing weak fault feature extraction is crucial to mechanical fault diagnosis and machine condition monitoring.Envelope analysis based on Hilbert transform has been widely used in bearing fault feature extraction. A generalization of the Hilbert transform, the fractional Hilbert transform is defined in the frequency domain, it is based upon the modification of spatial filter with a fractional parameter, and it can be used to construct a new kind of fractional analytic signal. By performing spectrum analysis on the fractional envelope signal, the fractional envelope spectrum can be obtained. When weak faults occur in a bearing, some of the characteristic frequencies will clearly appear in the fractional envelope spectrum. These characteristic frequencies can be used for bearing weak fault feature extraction.The effectiveness of the proposed method is verified through simulation signal and experiment data.展开更多
This paper is concerned with fundamental properties of a class of composite systems with fractional degree generalized frequency variables, including controllability, observability and stability. Firstly, some necessa...This paper is concerned with fundamental properties of a class of composite systems with fractional degree generalized frequency variables, including controllability, observability and stability. Firstly, some necessary and sufficient conditions are given to guarantee controllability and observability of such composite systems. Then we prove that the stability problem of such composite systems can be reduced to judging whether a fractional degree polynomial is stable. Finally, the stability analysis result is applied in the supervisory control of fractional-order multi-agent systems, and an example is provided to illustrate the effectiveness of the proposed methods.展开更多
Cyber-physical systems(CPSs) are man-made complex systems coupled with natural processes that, as a whole,should be described by distributed parameter systems(DPSs) in general forms. This paper presents three such gen...Cyber-physical systems(CPSs) are man-made complex systems coupled with natural processes that, as a whole,should be described by distributed parameter systems(DPSs) in general forms. This paper presents three such general models for generalized DPSs that can be used to characterize complex CPSs. These three different types of fractional operators based DPS models are: fractional Laplacian operator, fractional power of operator or fractional derivative. This research investigation is motivated by many fractional order models describing natural, physical, and anomalous phenomena, such as sub-diffusion process or super-diffusion process. The relationships among these three different operators are explored and explained. Several potential future research opportunities are then articulated followed by some conclusions and remarks.展开更多
This paper discusses the parameter and differentiation order identification of continuous fractional order Ki Ba M models in ARX(autoregressive model with exogenous inputs)and OE(output error model) forms. The least s...This paper discusses the parameter and differentiation order identification of continuous fractional order Ki Ba M models in ARX(autoregressive model with exogenous inputs)and OE(output error model) forms. The least squares method is applied to the identification of nonlinear and linear parameters,in which the Grunwald-Letnikov definition and short memory principle are applied to compute the fractional order derivatives.An adaptive P-type order learning law is proposed to estimate the differentiation order iteratively and accurately. Particularly,a unique estimation result and a fast convergence speed can be arrived by using the small gain strategy, which is unidirectional and has certain advantages than some state-of-art methods. The proposed strategy can be successfully applied to the nonlinear systems with quasi-linear characteristics. The numerical simulations are shown to validate the concepts.展开更多
Recent advances in modeling and control of crowd of pedestrians are briefly surveyed in this paper.Possibilities of applying fractional calculus in the modeling of crowd of pedestrians have been shortly reviewed and d...Recent advances in modeling and control of crowd of pedestrians are briefly surveyed in this paper.Possibilities of applying fractional calculus in the modeling of crowd of pedestrians have been shortly reviewed and discussed from different aspects such as descriptions of motion,interactions of long range and effects of memory.Control of the crowd of pedestrians have also been formulated using the framework of cyber-physical systems and been realized using networked Segways with onboard emergency response personnels to regulate the velocity and flux of the crowd.Platform for verification of the theoretical results are also provided in this paper.展开更多
This paper focuses on the H_∞ output feedback control problem of linear time-invariant fractional-order systems over finite frequency range. Based on the generalized KalmanYakubovic-Popov(KYP) Lemma and a key project...This paper focuses on the H_∞ output feedback control problem of linear time-invariant fractional-order systems over finite frequency range. Based on the generalized KalmanYakubovic-Popov(KYP) Lemma and a key projection lemma, a necessary and sufficient condition is established to ensure the existence of the H_∞ output feedback controller over finite frequency range, a desirable property in control engineering practice. By using the matrix congruence transformation, the feedback control gain matrix is decoupled and further parameterized by a scalar matrix. Two iterative linear matrix inequality algorithms are developed to solve this problem. Finally, numerical examples are provided to illustrate the effectiveness of the proposed method.展开更多
I.INTRODUCTION FRACTIONAL calculus has been applied in all MAD(modeling,analysis and design)aspects of control systems engineering since Shunji Manabe’s pioneering work in early 1960s.The 2016 International Conferenc...I.INTRODUCTION FRACTIONAL calculus has been applied in all MAD(modeling,analysis and design)aspects of control systems engineering since Shunji Manabe’s pioneering work in early 1960s.The 2016 International Conference on Fractional Differentiation and Its Applications(ICFDA)was held in Novi Sad,Serbia,July 18-20.Quoting from the展开更多
Proton exchange membrane fuel cell(PEMFC) is widely recognized as a potentially renewable and green energy source based on hydrogen. Maximum power point tracking(MPPT) is one of the most important working conditions t...Proton exchange membrane fuel cell(PEMFC) is widely recognized as a potentially renewable and green energy source based on hydrogen. Maximum power point tracking(MPPT) is one of the most important working conditions to be considered. In order to improve the performance such as convergence and robustness under disturbance and uncertainty,a fractional order high pass filter(FOHPF) is applied for the MPPT controller design based on the traditional extremum seeking control(ESC). The controller is designed with integerorder integrator(IO-I) and low pass filter(IO-LPF) together with fractional order high pass filter(FOHPF), by substituting the normal HPF in the original ESC system. With this FOHPF ESC,better convergence and smoother performance are achieved while maintaining the robust specifications. First, tracking stability is discussed under the commensurate-order condition. Then,simulation results are included to validate the proposed new FOHPF ESC scheme under disturbance. Finally, comparison results between FOHPF ESC and the traditional ESC method are also provided.展开更多
This paper reviews research that studies the principle of self-support(PSS) in some control systems and proposes a fractional-order generalized PSS framework for the first time.The existing PSS approach focuses on pra...This paper reviews research that studies the principle of self-support(PSS) in some control systems and proposes a fractional-order generalized PSS framework for the first time.The existing PSS approach focuses on practical tracking problem of integer-order systems including robotic dynamics,high precision linear motor system,multi-axis high precision positioning system with unmeasurable variables,imprecise sensor information,uncertain parameters and external disturbances.More generally,by formulating the fractional PSS concept as a new generalized framework,we will focus on the possible fields of the fractional-order control problems such as practical tracking,λ-tracking,etc.of robot systems,multiple mobile agents,discrete dynamical systems,time delay systems and other uncertain nonlinear systems.Finally,the practical tracking of a first-order uncertain model of automobile is considered as a simple example to demonstrate the efficiency of the fractional-order generalized principle of self-support(FOGPSS) control strategy.展开更多
In recent years,the epidemic model with anomalous diffusion has gained popularity in the literature.However,when introducing anomalous diffusion into epidemic models,they frequently lack physical explanation,in contra...In recent years,the epidemic model with anomalous diffusion has gained popularity in the literature.However,when introducing anomalous diffusion into epidemic models,they frequently lack physical explanation,in contrast to the traditional reaction-diffusion epidemic models.The point of this paper is to guarantee that anomalous diffusion systems on infectious disease spreading remain physically reasonable.Specifically,based on the continuous-time random walk(CTRW),starting from two stochastic processes of the waiting time and the step length,time-fractional space-fractional diffusion,timefractional reaction-diffusion and fractional-order diffusion can all be naturally introduced into the SIR(S:susceptible,I:infectious and R:recovered)epidemic models,respectively.The three models mentioned above can also be applied to create SIR epidemic models with generalized distributed time delays.Distributed time delay systems can also be reduced to existing models,such as the standard SIR model,the fractional infectivity model and others,within the proper bounds.Meanwhile,as an application of the above stochastic modeling method,the physical meaning of anomalous diffusion is also considered by taking the SEIR(E:exposed)epidemic model as an example.Similar methods can be used to build other types of epidemic models,including SIVRS(V:vaccine),SIQRS(Q:quarantined)and others.Finally,this paper describes the transmission of infectious disease in space using the real data of COVID-19.展开更多
In this paper,we present a soil methane emissions suppression approach using swarms of unmanned aerial vehicles(UAVs),by spreading biochar mulch on top of the detected methane emissions area/source.Soil microorganisms...In this paper,we present a soil methane emissions suppression approach using swarms of unmanned aerial vehicles(UAVs),by spreading biochar mulch on top of the detected methane emissions area/source.Soil microorganisms can produce methane and release it into the atmosphere causing climate change such as global warming.However,people lack methods to manage soil methane emissions,especially quantification of methane emissions from the soil.Current measurement and suppression of methane methods are often limited due to the maintenance,installation,and calibration requirements of these sensing systems.To overcome these drawbacks,we present a new method called FADE-MAS2D(Fractional Advection Diffusion Mobile Actuator and Sensor)in which swarming UAVs are applied as optimal coverage control actuators to various methane release scenarios(from single to multi-source disturbances)utilizing an anomalous diffusion model with different time,and space fractional orders subject to wind fields.This strategy is based on the premise that methane diffusion can be modeled as an anomalous diffusion equation,and swarming UAVs can be applied to tackle the optimal coverage control issue.To simulate methane diffusion under the wind,we utilize the fractional calculus to solve the anomalous diffusion equation and define wind force with the drag equation.In addition,we integrated emissions control,UAV control efforts,and UAV location error in our cost function.Finally,we evaluated our approach using simulation experiments with methane diffusion and multiple methane emission sources in the time and space domain,respectively.The results show that when α=0.8 and β=1.8,the shape and emissions of methane perform well.Furthermore,our approach resulted in great control performance with multiple methane emission sources and different wind velocities and directions.展开更多
This paper focuscs on the recent progress in the adoption of active disturbance rejection control(ADRC)in thermal pro-cesses as a viable alternative to proportional-_integral-derivative(PID),especially in coa-fired po...This paper focuscs on the recent progress in the adoption of active disturbance rejection control(ADRC)in thermal pro-cesses as a viable alternative to proportional-_integral-derivative(PID),especially in coa-fired power plants.The profound interpretation of this paradigm shift,with backward compatibility,is discussed in detail.A few fundamental issues associated with ADRC's applications in thermal processes are discussed,such as implementation,tuning,and the structural changes.Examples and case studies are presented,encompassing coal-fired power plants,gas turbines and nuclear power plants,as well as highlighting results of field applications.Also discussed are future research opportunities brought by ADRC's entry as the baseline control technology in thermal processes.展开更多
Mechanical response and simulation for constitutive equation with distributed order derivatives were considered.We investigated the creep compliance,creep recovery,relaxation modulus,stress–strain behavior under harm...Mechanical response and simulation for constitutive equation with distributed order derivatives were considered.We investigated the creep compliance,creep recovery,relaxation modulus,stress–strain behavior under harmonic deformation for each case of two constitutive equations.We express these responses and results as easily computable forms and simulate them by using MATHEMATICA 8.The results involve the exponential integral function,convergent improper integrals on the infinite interval(0,+∞)and the numerical integral method for the convolution integral.For both equations,stress responses to harmonic deformation display hysteresis phenomena and energy dissipation.The two constitutive equations characterize viscoelastic models of fluid-like and solid-like,respectively.展开更多
基金supported by SGC project5 entitled"Mobile Biochar Production for Methane Emission Reduction and Soil Amendment".Grant Agreement#CCR20014supported in part by NSF CBET#1856112supported in part by an F3 R&D GSR Award (Farms Food Future Innovation Initiative (or F3),as funded by US Dept.of Commerce,Economic Development Administration Build Back Better Regional Challenge).
文摘Agricultural and forestry biomass can be converted to biochar through pyrolysis gasification,making it a significant carbon source for soil.Applying biochar to soil is a carbon-negative process that helps combat climate change,sustain soil biodiversity,and regulate water cycling.However,quantifying soil carbon content conventionally is time-consuming,labor-intensive,imprecise,and expensive,making it difficult to accurately measure in-field soil carbon’s effect on storage water and nutrients.To address this challenge,this paper for the first time,reports on extensive lab tests demonstrating non-intrusive methods for sensing soil carbon and related smart biochar applications,such as differentiating between biochar types from various biomass feedstock species,monitoring soil moisture,and biochar water retention capacity using portable microwave and millimeter wave sensors,and machine learning.These methods can be scaled up by deploying the sensor in-field on a mobility platform,either ground or aerial.The paper provides details on the materials,methods,machine learning workflow,and results of our investigations.The significance of this work lays the foundation for assessing carbon-negative technology applications,such as soil carbon content accounting.We validated our quantification method using supervised machine learning algorithms by collecting real soil mixed with known biochar contents in the field.The results show that the millimeter wave sensor achieves high sensing accuracy(up to 100%)with proper classifiers selected and outperforms the microwave sensor by approximately 10%–15%accuracy in sensing soil carbon content.
基金supported by National Natural Science Foundation of China(61074161,61273103,61374061)Nantong Science and Technology Plan Project(MS22016051)
文摘The bearing weak fault feature extraction is crucial to mechanical fault diagnosis and machine condition monitoring.Envelope analysis based on Hilbert transform has been widely used in bearing fault feature extraction. A generalization of the Hilbert transform, the fractional Hilbert transform is defined in the frequency domain, it is based upon the modification of spatial filter with a fractional parameter, and it can be used to construct a new kind of fractional analytic signal. By performing spectrum analysis on the fractional envelope signal, the fractional envelope spectrum can be obtained. When weak faults occur in a bearing, some of the characteristic frequencies will clearly appear in the fractional envelope spectrum. These characteristic frequencies can be used for bearing weak fault feature extraction.The effectiveness of the proposed method is verified through simulation signal and experiment data.
基金supported by Foundation of Shanxi Scholarship Council(2016-075)Natural Science Foundation of Shanxi Normal University(ZR1601)Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province(2018-25)
文摘This paper is concerned with fundamental properties of a class of composite systems with fractional degree generalized frequency variables, including controllability, observability and stability. Firstly, some necessary and sufficient conditions are given to guarantee controllability and observability of such composite systems. Then we prove that the stability problem of such composite systems can be reduced to judging whether a fractional degree polynomial is stable. Finally, the stability analysis result is applied in the supervisory control of fractional-order multi-agent systems, and an example is provided to illustrate the effectiveness of the proposed methods.
基金supported by Chinese Universities Scientific Fund(CUSF-DHD-2014061)Natural Science Foundation of Shanghai(15ZR1400800)
文摘Cyber-physical systems(CPSs) are man-made complex systems coupled with natural processes that, as a whole,should be described by distributed parameter systems(DPSs) in general forms. This paper presents three such general models for generalized DPSs that can be used to characterize complex CPSs. These three different types of fractional operators based DPS models are: fractional Laplacian operator, fractional power of operator or fractional derivative. This research investigation is motivated by many fractional order models describing natural, physical, and anomalous phenomena, such as sub-diffusion process or super-diffusion process. The relationships among these three different operators are explored and explained. Several potential future research opportunities are then articulated followed by some conclusions and remarks.
基金supported by the Major Scientific Instrument Development Program of the National Natural Science Foundation of China(61527809)the National Natural Science Foundation of China(61374101,61375084)+1 种基金the Key Program of Shandong Provincial Natural Science Foundation(ZR2015QZ08)of Chinathe Young Scholars Program of Shandong University(2015WLJH44)
文摘This paper discusses the parameter and differentiation order identification of continuous fractional order Ki Ba M models in ARX(autoregressive model with exogenous inputs)and OE(output error model) forms. The least squares method is applied to the identification of nonlinear and linear parameters,in which the Grunwald-Letnikov definition and short memory principle are applied to compute the fractional order derivatives.An adaptive P-type order learning law is proposed to estimate the differentiation order iteratively and accurately. Particularly,a unique estimation result and a fast convergence speed can be arrived by using the small gain strategy, which is unidirectional and has certain advantages than some state-of-art methods. The proposed strategy can be successfully applied to the nonlinear systems with quasi-linear characteristics. The numerical simulations are shown to validate the concepts.
基金supported by National Natural Science Foundation of China(61374055)Natural Science Foundation of Jiangsu Province(BK20131381)+4 种基金China Postdoctoral Science Foundation Funded Project(2013M541663)Jiangsu Planned Projects for Postdoctoral Research Funds(1202015C)Scientific Research Foundation for the Returned Overseas Chinese ScholarsState Education Ministry(BJ213022)Scientific Research Foundation of Nanjing University of Posts and Telecommunications(NY214075,XJKY14004)
文摘Recent advances in modeling and control of crowd of pedestrians are briefly surveyed in this paper.Possibilities of applying fractional calculus in the modeling of crowd of pedestrians have been shortly reviewed and discussed from different aspects such as descriptions of motion,interactions of long range and effects of memory.Control of the crowd of pedestrians have also been formulated using the framework of cyber-physical systems and been realized using networked Segways with onboard emergency response personnels to regulate the velocity and flux of the crowd.Platform for verification of the theoretical results are also provided in this paper.
文摘This paper focuses on the H_∞ output feedback control problem of linear time-invariant fractional-order systems over finite frequency range. Based on the generalized KalmanYakubovic-Popov(KYP) Lemma and a key projection lemma, a necessary and sufficient condition is established to ensure the existence of the H_∞ output feedback controller over finite frequency range, a desirable property in control engineering practice. By using the matrix congruence transformation, the feedback control gain matrix is decoupled and further parameterized by a scalar matrix. Two iterative linear matrix inequality algorithms are developed to solve this problem. Finally, numerical examples are provided to illustrate the effectiveness of the proposed method.
文摘I.INTRODUCTION FRACTIONAL calculus has been applied in all MAD(modeling,analysis and design)aspects of control systems engineering since Shunji Manabe’s pioneering work in early 1960s.The 2016 International Conference on Fractional Differentiation and Its Applications(ICFDA)was held in Novi Sad,Serbia,July 18-20.Quoting from the
基金supported by the Research Project Granted by Xihua University
文摘Proton exchange membrane fuel cell(PEMFC) is widely recognized as a potentially renewable and green energy source based on hydrogen. Maximum power point tracking(MPPT) is one of the most important working conditions to be considered. In order to improve the performance such as convergence and robustness under disturbance and uncertainty,a fractional order high pass filter(FOHPF) is applied for the MPPT controller design based on the traditional extremum seeking control(ESC). The controller is designed with integerorder integrator(IO-I) and low pass filter(IO-LPF) together with fractional order high pass filter(FOHPF), by substituting the normal HPF in the original ESC system. With this FOHPF ESC,better convergence and smoother performance are achieved while maintaining the robust specifications. First, tracking stability is discussed under the commensurate-order condition. Then,simulation results are included to validate the proposed new FOHPF ESC scheme under disturbance. Finally, comparison results between FOHPF ESC and the traditional ESC method are also provided.
基金supported by the National Natural Science Foundation of China(61304004,61503205)the Foundation of China Scholarship Council(201406715056)+1 种基金the Foundation of Changzhou Key Laboratory of Special Robot and Intelligent Technology(CZSR2014005)the Changzhou Science and Technology Program(CJ20160013)
文摘This paper reviews research that studies the principle of self-support(PSS) in some control systems and proposes a fractional-order generalized PSS framework for the first time.The existing PSS approach focuses on practical tracking problem of integer-order systems including robotic dynamics,high precision linear motor system,multi-axis high precision positioning system with unmeasurable variables,imprecise sensor information,uncertain parameters and external disturbances.More generally,by formulating the fractional PSS concept as a new generalized framework,we will focus on the possible fields of the fractional-order control problems such as practical tracking,λ-tracking,etc.of robot systems,multiple mobile agents,discrete dynamical systems,time delay systems and other uncertain nonlinear systems.Finally,the practical tracking of a first-order uncertain model of automobile is considered as a simple example to demonstrate the efficiency of the fractional-order generalized principle of self-support(FOGPSS) control strategy.
基金This work is supported in part by the National Natural Science Foundation of China(Grant Nos.62173027,62003026 and 61973329)the Natural Science Foundation of Beijing Municipality(Grant No.Z180005)Alianza UCMX seed funding(2020-2022)on Binational Collaborative Projects addressing COVID-19.
文摘In recent years,the epidemic model with anomalous diffusion has gained popularity in the literature.However,when introducing anomalous diffusion into epidemic models,they frequently lack physical explanation,in contrast to the traditional reaction-diffusion epidemic models.The point of this paper is to guarantee that anomalous diffusion systems on infectious disease spreading remain physically reasonable.Specifically,based on the continuous-time random walk(CTRW),starting from two stochastic processes of the waiting time and the step length,time-fractional space-fractional diffusion,timefractional reaction-diffusion and fractional-order diffusion can all be naturally introduced into the SIR(S:susceptible,I:infectious and R:recovered)epidemic models,respectively.The three models mentioned above can also be applied to create SIR epidemic models with generalized distributed time delays.Distributed time delay systems can also be reduced to existing models,such as the standard SIR model,the fractional infectivity model and others,within the proper bounds.Meanwhile,as an application of the above stochastic modeling method,the physical meaning of anomalous diffusion is also considered by taking the SEIR(E:exposed)epidemic model as an example.Similar methods can be used to build other types of epidemic models,including SIVRS(V:vaccine),SIQRS(Q:quarantined)and others.Finally,this paper describes the transmission of infectious disease in space using the real data of COVID-19.
基金support by a CSC Scholarship.DH is supported by an NSF NRT Fellowship-Grant DGE 1633722.
文摘In this paper,we present a soil methane emissions suppression approach using swarms of unmanned aerial vehicles(UAVs),by spreading biochar mulch on top of the detected methane emissions area/source.Soil microorganisms can produce methane and release it into the atmosphere causing climate change such as global warming.However,people lack methods to manage soil methane emissions,especially quantification of methane emissions from the soil.Current measurement and suppression of methane methods are often limited due to the maintenance,installation,and calibration requirements of these sensing systems.To overcome these drawbacks,we present a new method called FADE-MAS2D(Fractional Advection Diffusion Mobile Actuator and Sensor)in which swarming UAVs are applied as optimal coverage control actuators to various methane release scenarios(from single to multi-source disturbances)utilizing an anomalous diffusion model with different time,and space fractional orders subject to wind fields.This strategy is based on the premise that methane diffusion can be modeled as an anomalous diffusion equation,and swarming UAVs can be applied to tackle the optimal coverage control issue.To simulate methane diffusion under the wind,we utilize the fractional calculus to solve the anomalous diffusion equation and define wind force with the drag equation.In addition,we integrated emissions control,UAV control efforts,and UAV location error in our cost function.Finally,we evaluated our approach using simulation experiments with methane diffusion and multiple methane emission sources in the time and space domain,respectively.The results show that when α=0.8 and β=1.8,the shape and emissions of methane perform well.Furthermore,our approach resulted in great control performance with multiple methane emission sources and different wind velocities and directions.
基金This work was supported by the Science&Technology Research Project in Henan Province of China(No.212102311052)the National Key Research and Development Program of China(No.2016YFB0901405)the National Natural Science Foundation of China(No.61473265).
文摘This paper focuscs on the recent progress in the adoption of active disturbance rejection control(ADRC)in thermal pro-cesses as a viable alternative to proportional-_integral-derivative(PID),especially in coa-fired power plants.The profound interpretation of this paradigm shift,with backward compatibility,is discussed in detail.A few fundamental issues associated with ADRC's applications in thermal processes are discussed,such as implementation,tuning,and the structural changes.Examples and case studies are presented,encompassing coal-fired power plants,gas turbines and nuclear power plants,as well as highlighting results of field applications.Also discussed are future research opportunities brought by ADRC's entry as the baseline control technology in thermal processes.
基金the Natural Science Foundation of Shanghai(No.14ZR1440800)the Course Construction Project of Shanghai Municipal Education Commission(No.33210M161020).
文摘Mechanical response and simulation for constitutive equation with distributed order derivatives were considered.We investigated the creep compliance,creep recovery,relaxation modulus,stress–strain behavior under harmonic deformation for each case of two constitutive equations.We express these responses and results as easily computable forms and simulate them by using MATHEMATICA 8.The results involve the exponential integral function,convergent improper integrals on the infinite interval(0,+∞)and the numerical integral method for the convolution integral.For both equations,stress responses to harmonic deformation display hysteresis phenomena and energy dissipation.The two constitutive equations characterize viscoelastic models of fluid-like and solid-like,respectively.
