The large-aperture reflective cameras on the geostationary orbit are susceptible to significant temperature fluctuations due to the“Sun transit”effect.To address the shortcomings of existing thermal control measures...The large-aperture reflective cameras on the geostationary orbit are susceptible to significant temperature fluctuations due to the“Sun transit”effect.To address the shortcomings of existing thermal control measures using camera sunshades to suppress the“Sun transit”and the issue of excessively large solar avoidance angles determined solely by geometric relationships,a thermal control design method is proposed that involves adding multi-layer thermal protection at the secondary mirror position of the camera.The goal is to optimize the avoidance angle and enhance the camera’s tolerance to“Sun transit”.A heat balance and motion relationship between the avoidance angle and duration is established.Then,the minimum solar avoidance angle after adopting the multi-layer thermal protection design is calculated.This angle is compared with the one determined by geometric relationships,leading to the conclusion that this method can effectively enhance the camera’s tolerance to“Sun transit”.A heat dissipation scheme is proposed that involves a coupled north-south heat spreader design with low-temperature compensation for the internal heat source.The calculation results of the two avoidance angles are applied to the calculation of the heat dissipation area and low-temperature compensation power,achieving a closed-loop heat dissipation scheme.Puls,the superiority of the multi-layer thermal protection design method is demonstrated from the perspectives of heat dissipation area and low-temperature compensation power requirements.A comparative analysis of simulation analysis,thermal balance tests,and in-orbit temperature data further validates the effectiveness of this method.展开更多
This paper examines the design concept and mobile control strategy of the human assistant robot I-PENTAR(inverted pendulum type assistant robot). The motion equation is derived considering the non-holonomic constraint...This paper examines the design concept and mobile control strategy of the human assistant robot I-PENTAR(inverted pendulum type assistant robot). The motion equation is derived considering the non-holonomic constraint of the twowheeled mobile robot. Different optimal control approaches are applied to a linearized model of I-PENTAR. These include linear quadratic regulator(LQR), linear quadratic Gaussian control(LQG), H_2 control and H_∞ control. Simulation is performed for all the approaches yielding good performance results.展开更多
μ-synthesis is a practical design approach and has been applied successfully to achieve a nominal and robust performance objectives. However, this design method suffers from the complexity of its practical implementa...μ-synthesis is a practical design approach and has been applied successfully to achieve a nominal and robust performance objectives. However, this design method suffers from the complexity of its practical implementation and high computational demand due to its high order dynamics. To overcome this problem, the interaction between fuzzy logic control which is a part of intelligence control theory and p-synthesis controller is carried out. This is called integrated fuzzy robust controller in this paper. It is obtained by coupling fuzzy pd with p-synthesis controller through the outer loop. Using this design strategy, we can keep the system performance and robustness even a high order p-synthesis controller is reduced into second order model. In order to test the effectiveness of this design method, the linear simulation results for a launch vehicle＇s attitude control motion are presented at the end of this paper.展开更多
The mathematical model of quadcopter-unmanned aerial vehicle （UAV） is derived by using two approaches： One is the Newton-Euler approach which is formulated using classical meehanics; and other is the Euler-Lagrange...The mathematical model of quadcopter-unmanned aerial vehicle （UAV） is derived by using two approaches： One is the Newton-Euler approach which is formulated using classical meehanics; and other is the Euler-Lagrange approach which describes the model in terms of kinetic （translational and rotational） and potential energy. The proposed quadcopter＇s non-linear model is incorporated with aero-dynamical forces generated by air resistance, which helps aircraft to exhibits more realistic behavior while hovering. Based on the obtained model, the suitable control strategy is developed, under which two effective flight control systems are developed. Each control system is created by cascading the proportional-derivative （PD） and T-S fuzzy controllers that are equipped with six and twelve feedback signals individually respectively to ensure better tracking, stabilization, and response. Both pro- posed flight control designs are then implemented with the quadcopter model respectively and multitudinous simulations are conducted using MATLAB/Simulink to analyze the tracking performance of the quadcopter model at various reference inputs and trajectories.展开更多
Scaled physical model tests for steam breakthrough were conducted based on the analysis of mechanisms and influence factors of steam breakthrough. Physical simulation results showed that at the initial steam breakthro...Scaled physical model tests for steam breakthrough were conducted based on the analysis of mechanisms and influence factors of steam breakthrough. Physical simulation results showed that at the initial steam breakthrough, preferential flow channels were formed in narrow sand packs and most residual oil left in these channels was immobile. This shortened the steam breakthrough time of follow-up steam flooding and decreased the increment of oil recovery efficiency. Steam breakthrough occurred easily for a smaller producer-injector spacing, and a bigger difference in physical properties between fluids and rock. Steam breakthrough is more likely to occur at a larger formation permeability （k）, greater steam displacement velocity （u） and smaller producer-injector spacing （L）. Steam breakthrough time is a function of the parameter group （uk/L）, i.e. tb=3.2151 （uk/L）^-0.5142. A non piston-like displacement model was built based on steam breakthrough observation for a steam stimulated well in the Jinglou Oilfield, Henan Oilfield Company. The steam volume swept in different directions could be obtained from inter-well permeability capacity and breakthrough angle, and the steam swept pore volume （SSPV） was also determined. Numerical simulation showed that steam sweep efficiency reached its peak value when a slug of profile control agent （slug size 10%-15% SSPV） was set at one half of the inter-well spacing. Field test with 12.5% SSPV of profile control agents in the Jinglou Oilfield achieved success in sealing breakthrough channels and good production performance of adjacent producers.展开更多
Background: Binary as well as polytomous logistic models are widely used for estimating odds ratios when the exposure of prime interest assumes unordered multiple levels under matched pairs case-control design. In our...Background: Binary as well as polytomous logistic models are widely used for estimating odds ratios when the exposure of prime interest assumes unordered multiple levels under matched pairs case-control design. In our previous studies, we have shown that the use of a polytomous logistic model for estimating cumulative odds ratios when the outcome (response) variable is ordinal (in addition to being polytomous) under matched pairs case-control design. The cumulative odds ratios were estimated based on separate fitting of the model at each of the cutpoint level as compared to less than equal to that level. In this paper we propose an alternative method of estimating the cumulative odds ratios and reanalyze the Los Angeles Endometrial Cancer data in the context of dose levels of conjugated oestrogen exposure and development of endometrial cancer under the matched pair case-control design. Methods: In the present study, the cumulative logit model is fitted using a single multinomial logit model for the data. For this, the full maximum likelihood estimation procedure is adopted. A test for equality of the cumulative odds ratios across the exposure levels is proposed. Results: The analysis revealed that there is a strong evidence of risk for developing endometrial cancer due to oestrogen exposure above each of the three dose level as compared to less than equal to that level. The estimated values at the three cutpoint levels were found to be 6.17, 3.60 and 5.16 respectively. Conclusions: The odds of developing endometrial cancer are very high for the users of any amount of oestrogen, even if it is the least dose, as compared to the non-users.展开更多
During the excavation and support process in deep soft rocks,complex conditions such as high stress and strong disturbance can be encountered.The complex conditions can cause failure of the support system.Aiming at st...During the excavation and support process in deep soft rocks,complex conditions such as high stress and strong disturbance can be encountered.The complex conditions can cause failure of the support system.Aiming at stability control in deep soft rocks,we proposed the excavation compensation theory.A new high strength and high toughness material was developed.The breaking load and elongation of the new material are 1.59 and 1.78 times that of common bolt materials.To overcome the problem that the CABLE element in FLAC^(3D) cannot simulate failure of support structures,the numerical model for the whole process of force-breaking-anchorage failure simulation(FBAS)for bolts(cables)was established.The numerical experiments on the excavation compensation control of deep soft rock were carried out.The excavation compensation control mechanism of high strength and high toughness material was clarified.Compared with the common support scheme,the highly prestressed support has a maximum increase of 90.24%in radial stress compensation rate and a maximum increase of 67.85%in deformation control rate.The results illustrate the rationality of the excavation compensation theory.The compensation design method of excavations in deep soft rocks was proposed and applied in a deep soft rock chamber.The monitoring indicated that the maximum surrounding rock deformation is 180 mm,reduced by 64%compared to the common support.The deformation of the chamber was controlled and the surrounding rock was stable.展开更多
Aiming at the problems of poor adaptability and insufficient fault prediction of traditional mechanical automation control systems in complex working conditions,a mechanical automation control system based on artifici...Aiming at the problems of poor adaptability and insufficient fault prediction of traditional mechanical automation control systems in complex working conditions,a mechanical automation control system based on artificial intelligence is designed.This design integrates expert control,fuzzy control,and neural network control technologies,and builds a hierarchical distributed architecture.Fault warning adopts threshold judgment and dynamic time warping pattern recognition technologies,and state monitoring realizes accurate analysis through multi-source data fusion and Kalman filtering algorithm.Practical applications show that this system can reduce the equipment failure rate by more than 30%.With the help of intelligent scheduling optimization,it can significantly improve production efficiency and reduce energy consumption,providing a reliable technical solution and practical path for the intelligent upgrade of the mechanical automation field.展开更多
Variable Cycle Engine(VCE)serves as the core system in achieving future advanced fighters with cross-generational performance and mission versatility.However,the resultant complex configuration and strong coupling of ...Variable Cycle Engine(VCE)serves as the core system in achieving future advanced fighters with cross-generational performance and mission versatility.However,the resultant complex configuration and strong coupling of control parameters present significant challenges in designing acceleration and deceleration control schedules.To thoroughly explore the performance potential of engine,a global integration design method for acceleration and deceleration control schedule based on inner and outer loop optimization is proposed.The outer loop optimization module employs Integrated Surrogate-Assisted Co-Differential Evolutionary(ISACDE)algorithm to optimize the variable geometry adjustment laws based on B-spline curve,and the inner loop optimization module adopts the fixed-state method to design the open-loop fuel–air ratio control schedules,which are aimed at minimizing the acceleration and deceleration time under multiple constraints.Simulation results demonstrate that the proposed global integration design method not only furthest shortens the acceleration and deceleration time,but also effectively safeguards the engine from overlimit.展开更多
This paper presents a design method of H<sub>2</sub> and H<sub>∞</sub>-feedback control loop for nonlinear smooth gene networks that are in control affine form. Formulaic solution methodology ...This paper presents a design method of H<sub>2</sub> and H<sub>∞</sub>-feedback control loop for nonlinear smooth gene networks that are in control affine form. Formulaic solution methodology for solving the nonlinear partial differential equations, namely the Hamilton-Jacobi-Bellman and Hamilton-Jacobi-Isaacs equations through successive Galerkin’s approximation is implemented and the results are compared. Throughout the implementation, there were several caveats that need to be further resolved for practical applications in general cases. Such issues and the clarification of causes are mathematically established and reviewed.展开更多
Traditional centralized Proportional Integral(PI)controller design methods based on Equivalent Transfer Functions(ETFs)have poor decoupling effect in turboprop engines.In this paper,a centralized PI design method base...Traditional centralized Proportional Integral(PI)controller design methods based on Equivalent Transfer Functions(ETFs)have poor decoupling effect in turboprop engines.In this paper,a centralized PI design method based on dynamic imaginary matrix and equivalent transfer function is proposed.Firstly,a method for solving equivalent transfer functions based on the dynamic imaginary matrix is proposed,which adopts dynamic imaginary matrix to describe the dynamic characteristics of the system,and obtains the equivalent transfer function based on the dynamic imaginary matrix characteristics.Secondly,for the equivalent transfer function,a central-ized PI control gain is designed using the Taylor expansion method.Meanwhile,this paper further proves that the centralized PI design method proposed in this paper has integral stability.Consid-ering the impact of altitude and Mach number on turboprop engines,a linear feedforward control method based on the transfer function matrix is further proposed based on the centralized PI con-troller,and the stability of the entire comprehensive control method is proved.Finally,to ensure the safe and effective operation of the turboprop engine,a temperature and torque limiting protection controller is designed for the turboprop engine.Simulation results show that the centralized PI con-troller design method and linear feedforward control method proposed can effectively improve the control quality of turboprop engine control systems.展开更多
In this paper, the dynamic observer-based controller design for a class of neutral systems with H∞ control is considered. An observer-based output feedback is derived for systems with polytopic parameter uncertaintie...In this paper, the dynamic observer-based controller design for a class of neutral systems with H∞ control is considered. An observer-based output feedback is derived for systems with polytopic parameter uncertainties. This controller assures delay-dependent stabilization and H∞ norm bound attenuation from the disturbance input to the controlled output. Numerical examples are provided for illustration and comparison of the proposed conditions.展开更多
The objective of the present study is to analytically investigate temperature effects of an axial-type seismic damper made of shape memory alloys(SMAs)equipped in steel frames.Based on a modified multilinear one dimen...The objective of the present study is to analytically investigate temperature effects of an axial-type seismic damper made of shape memory alloys(SMAs)equipped in steel frames.Based on a modified multilinear one dimensional constitutive model of SMAs,two types of SMAs are employed,which have different stress plateau and different stress growth rate with temperature increase.Temperature effects of SMA dampers on seismic performance upgrading are discussed in three aspects:different environment temperatures;rapid loading rate induced heat generation and different SMA fractions.The analysis indicates that the effect of environment temperature should be considered for the SMA damper in steel frames.However,the rapid loading rate induced heat generation has little adverse effect.展开更多
An iterative identification and control design method based on v-gap is given to ensure the stability of closed-loop system and control performance improvement. The whole iterative procedure includes three parts： the...An iterative identification and control design method based on v-gap is given to ensure the stability of closed-loop system and control performance improvement. The whole iterative procedure includes three parts： the optimal excitation signals design, the uncertainty model set identification and the stable controller design. Firstly the worst case v-gap is used as the criterion of the optimal excitation signals design, and the design is performed via the power spectrum optimization. And then, an uncertainty model set is attained by system identification on the basis of the measure signals. The controller is designed to ensure the stability of closed-loop system and the closed-loop performance improvement. Simulation result shows that the proposed method has good convergence and closed-loop control performance.展开更多
The Drag-Free and Attitude Control System(DFACS)is a critical platform for various space missions,including high precision satellite navigation,geoscience and gravity field measurement,and space scientific experiments...The Drag-Free and Attitude Control System(DFACS)is a critical platform for various space missions,including high precision satellite navigation,geoscience and gravity field measurement,and space scientific experiments.This paper presents a comprehensive review of over sixty years of research on the design and dynamics model of DFACS.Firstly,we examine the open literature on DFACS and its applications in Drag-Free missions,providing readers with necessary background information on the field.Secondly,we analyze the system configurations and main characteristics of different DFACSs,paying particular attention to the coupling mechanism between the system configuration and dynamics model.Thirdly,we summarize the dynamics modeling methods and main dynamics models of DFACS from multiple perspectives,including common fundamentals and specific applications.Lastly,we identify current challenges and technological difficulties in the system design and dynamics modeling of DFACS,while suggesting potential avenues for future research.This paper aims to provide readers with a comprehensive understanding of the state-of-the-art in DFACS research,as well as the future prospects and challenges in this field.展开更多
This article proposes a novel approach combining exponential-reaching-law-based equivalent control law with radial basis function (RBF) network-based switching law to strengthen the sliding mode control (SMC) tracking...This article proposes a novel approach combining exponential-reaching-law-based equivalent control law with radial basis function (RBF) network-based switching law to strengthen the sliding mode control (SMC) tracking capacity for systems with uncertainties and disturbances. First, SMC discrete equivalent control law is designed on the basis of the nominal model of the system and the adaptive exponential reaching law, and subsequently, stability of the algorithm is analyzed. Second, RBF network is used to f...展开更多
This paper focuses on damage control design of SMA dampers in steel frame piers.A parametric study based on time history analyses is carried out on frametyped bridge piers with axial-type SMA damping device.The parame...This paper focuses on damage control design of SMA dampers in steel frame piers.A parametric study based on time history analyses is carried out on frametyped bridge piers with axial-type SMA damping device.The parameters examined are design parameters of strength ratioαF and stiffness ratioαK.Seismic performance indexes on displacement and strain are investigated under three JRA recommended Level 2 Ground TypeПstrong earthquake motions.Design recommendations are suggested following the results of the parametric study.展开更多
基金supported by the Na⁃tional Key Research and Development Program of China(No.2021YFC2202102)。
文摘The large-aperture reflective cameras on the geostationary orbit are susceptible to significant temperature fluctuations due to the“Sun transit”effect.To address the shortcomings of existing thermal control measures using camera sunshades to suppress the“Sun transit”and the issue of excessively large solar avoidance angles determined solely by geometric relationships,a thermal control design method is proposed that involves adding multi-layer thermal protection at the secondary mirror position of the camera.The goal is to optimize the avoidance angle and enhance the camera’s tolerance to“Sun transit”.A heat balance and motion relationship between the avoidance angle and duration is established.Then,the minimum solar avoidance angle after adopting the multi-layer thermal protection design is calculated.This angle is compared with the one determined by geometric relationships,leading to the conclusion that this method can effectively enhance the camera’s tolerance to“Sun transit”.A heat dissipation scheme is proposed that involves a coupled north-south heat spreader design with low-temperature compensation for the internal heat source.The calculation results of the two avoidance angles are applied to the calculation of the heat dissipation area and low-temperature compensation power,achieving a closed-loop heat dissipation scheme.Puls,the superiority of the multi-layer thermal protection design method is demonstrated from the perspectives of heat dissipation area and low-temperature compensation power requirements.A comparative analysis of simulation analysis,thermal balance tests,and in-orbit temperature data further validates the effectiveness of this method.
基金supported by the Deanship of Scientific Research(DSR)at the King Fahd University of Petroleum and Minerals(KFUPM)(141048)
文摘This paper examines the design concept and mobile control strategy of the human assistant robot I-PENTAR(inverted pendulum type assistant robot). The motion equation is derived considering the non-holonomic constraint of the twowheeled mobile robot. Different optimal control approaches are applied to a linearized model of I-PENTAR. These include linear quadratic regulator(LQR), linear quadratic Gaussian control(LQG), H_2 control and H_∞ control. Simulation is performed for all the approaches yielding good performance results.
文摘μ-synthesis is a practical design approach and has been applied successfully to achieve a nominal and robust performance objectives. However, this design method suffers from the complexity of its practical implementation and high computational demand due to its high order dynamics. To overcome this problem, the interaction between fuzzy logic control which is a part of intelligence control theory and p-synthesis controller is carried out. This is called integrated fuzzy robust controller in this paper. It is obtained by coupling fuzzy pd with p-synthesis controller through the outer loop. Using this design strategy, we can keep the system performance and robustness even a high order p-synthesis controller is reduced into second order model. In order to test the effectiveness of this design method, the linear simulation results for a launch vehicle＇s attitude control motion are presented at the end of this paper.
基金supported by the National Natural Science Foundation of China(Nos.61673209,61741313,61304223)the Aeronautical Science Foundation(Nos.2016ZA52009)+1 种基金the Jiangsu Six Peak of Talents Program(No.KTHY-027)the Fundamental Research Funds for the Central Universities(Nos.NJ20160026,NS2017015)
文摘The mathematical model of quadcopter-unmanned aerial vehicle （UAV） is derived by using two approaches： One is the Newton-Euler approach which is formulated using classical meehanics; and other is the Euler-Lagrange approach which describes the model in terms of kinetic （translational and rotational） and potential energy. The proposed quadcopter＇s non-linear model is incorporated with aero-dynamical forces generated by air resistance, which helps aircraft to exhibits more realistic behavior while hovering. Based on the obtained model, the suitable control strategy is developed, under which two effective flight control systems are developed. Each control system is created by cascading the proportional-derivative （PD） and T-S fuzzy controllers that are equipped with six and twelve feedback signals individually respectively to ensure better tracking, stabilization, and response. Both pro- posed flight control designs are then implemented with the quadcopter model respectively and multitudinous simulations are conducted using MATLAB/Simulink to analyze the tracking performance of the quadcopter model at various reference inputs and trajectories.
文摘Scaled physical model tests for steam breakthrough were conducted based on the analysis of mechanisms and influence factors of steam breakthrough. Physical simulation results showed that at the initial steam breakthrough, preferential flow channels were formed in narrow sand packs and most residual oil left in these channels was immobile. This shortened the steam breakthrough time of follow-up steam flooding and decreased the increment of oil recovery efficiency. Steam breakthrough occurred easily for a smaller producer-injector spacing, and a bigger difference in physical properties between fluids and rock. Steam breakthrough is more likely to occur at a larger formation permeability （k）, greater steam displacement velocity （u） and smaller producer-injector spacing （L）. Steam breakthrough time is a function of the parameter group （uk/L）, i.e. tb=3.2151 （uk/L）^-0.5142. A non piston-like displacement model was built based on steam breakthrough observation for a steam stimulated well in the Jinglou Oilfield, Henan Oilfield Company. The steam volume swept in different directions could be obtained from inter-well permeability capacity and breakthrough angle, and the steam swept pore volume （SSPV） was also determined. Numerical simulation showed that steam sweep efficiency reached its peak value when a slug of profile control agent （slug size 10%-15% SSPV） was set at one half of the inter-well spacing. Field test with 12.5% SSPV of profile control agents in the Jinglou Oilfield achieved success in sealing breakthrough channels and good production performance of adjacent producers.
文摘Background: Binary as well as polytomous logistic models are widely used for estimating odds ratios when the exposure of prime interest assumes unordered multiple levels under matched pairs case-control design. In our previous studies, we have shown that the use of a polytomous logistic model for estimating cumulative odds ratios when the outcome (response) variable is ordinal (in addition to being polytomous) under matched pairs case-control design. The cumulative odds ratios were estimated based on separate fitting of the model at each of the cutpoint level as compared to less than equal to that level. In this paper we propose an alternative method of estimating the cumulative odds ratios and reanalyze the Los Angeles Endometrial Cancer data in the context of dose levels of conjugated oestrogen exposure and development of endometrial cancer under the matched pair case-control design. Methods: In the present study, the cumulative logit model is fitted using a single multinomial logit model for the data. For this, the full maximum likelihood estimation procedure is adopted. A test for equality of the cumulative odds ratios across the exposure levels is proposed. Results: The analysis revealed that there is a strong evidence of risk for developing endometrial cancer due to oestrogen exposure above each of the three dose level as compared to less than equal to that level. The estimated values at the three cutpoint levels were found to be 6.17, 3.60 and 5.16 respectively. Conclusions: The odds of developing endometrial cancer are very high for the users of any amount of oestrogen, even if it is the least dose, as compared to the non-users.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFC3805700)the National Natural Science Foundation of China(Grant No.42277174)the Fundamental Research Funds for the Central Universities,China(Grant No.2024JCCXSB01).
文摘During the excavation and support process in deep soft rocks,complex conditions such as high stress and strong disturbance can be encountered.The complex conditions can cause failure of the support system.Aiming at stability control in deep soft rocks,we proposed the excavation compensation theory.A new high strength and high toughness material was developed.The breaking load and elongation of the new material are 1.59 and 1.78 times that of common bolt materials.To overcome the problem that the CABLE element in FLAC^(3D) cannot simulate failure of support structures,the numerical model for the whole process of force-breaking-anchorage failure simulation(FBAS)for bolts(cables)was established.The numerical experiments on the excavation compensation control of deep soft rock were carried out.The excavation compensation control mechanism of high strength and high toughness material was clarified.Compared with the common support scheme,the highly prestressed support has a maximum increase of 90.24%in radial stress compensation rate and a maximum increase of 67.85%in deformation control rate.The results illustrate the rationality of the excavation compensation theory.The compensation design method of excavations in deep soft rocks was proposed and applied in a deep soft rock chamber.The monitoring indicated that the maximum surrounding rock deformation is 180 mm,reduced by 64%compared to the common support.The deformation of the chamber was controlled and the surrounding rock was stable.
文摘Aiming at the problems of poor adaptability and insufficient fault prediction of traditional mechanical automation control systems in complex working conditions,a mechanical automation control system based on artificial intelligence is designed.This design integrates expert control,fuzzy control,and neural network control technologies,and builds a hierarchical distributed architecture.Fault warning adopts threshold judgment and dynamic time warping pattern recognition technologies,and state monitoring realizes accurate analysis through multi-source data fusion and Kalman filtering algorithm.Practical applications show that this system can reduce the equipment failure rate by more than 30%.With the help of intelligent scheduling optimization,it can significantly improve production efficiency and reduce energy consumption,providing a reliable technical solution and practical path for the intelligent upgrade of the mechanical automation field.
基金supported by the Basic Research on Dynamic Real-time Modeling and Onboard Adaptive Modeling of Aero Engine,China(No.QZPY202308)。
文摘Variable Cycle Engine(VCE)serves as the core system in achieving future advanced fighters with cross-generational performance and mission versatility.However,the resultant complex configuration and strong coupling of control parameters present significant challenges in designing acceleration and deceleration control schedules.To thoroughly explore the performance potential of engine,a global integration design method for acceleration and deceleration control schedule based on inner and outer loop optimization is proposed.The outer loop optimization module employs Integrated Surrogate-Assisted Co-Differential Evolutionary(ISACDE)algorithm to optimize the variable geometry adjustment laws based on B-spline curve,and the inner loop optimization module adopts the fixed-state method to design the open-loop fuel–air ratio control schedules,which are aimed at minimizing the acceleration and deceleration time under multiple constraints.Simulation results demonstrate that the proposed global integration design method not only furthest shortens the acceleration and deceleration time,but also effectively safeguards the engine from overlimit.
文摘This paper presents a design method of H<sub>2</sub> and H<sub>∞</sub>-feedback control loop for nonlinear smooth gene networks that are in control affine form. Formulaic solution methodology for solving the nonlinear partial differential equations, namely the Hamilton-Jacobi-Bellman and Hamilton-Jacobi-Isaacs equations through successive Galerkin’s approximation is implemented and the results are compared. Throughout the implementation, there were several caveats that need to be further resolved for practical applications in general cases. Such issues and the clarification of causes are mathematically established and reviewed.
基金support by the National Natural Science Foundation of China (No.52202474)China Postdoctoral Science Foundation (No.2023M731655)+3 种基金Major Projects of National Science and Technology,China (No.J2019-I-0020-0019)Advanced Aviation Power Innovation Workstation Project,China (No.HKCX2022-01-026-03)Basic Research Business Fees for Central Universities,China (No.NT2023004)Nanjing University of Aeronautics and Astronautics Forward-looking Layout Research Project,China (No.1002-ILA22037-1A22).
文摘Traditional centralized Proportional Integral(PI)controller design methods based on Equivalent Transfer Functions(ETFs)have poor decoupling effect in turboprop engines.In this paper,a centralized PI design method based on dynamic imaginary matrix and equivalent transfer function is proposed.Firstly,a method for solving equivalent transfer functions based on the dynamic imaginary matrix is proposed,which adopts dynamic imaginary matrix to describe the dynamic characteristics of the system,and obtains the equivalent transfer function based on the dynamic imaginary matrix characteristics.Secondly,for the equivalent transfer function,a central-ized PI control gain is designed using the Taylor expansion method.Meanwhile,this paper further proves that the centralized PI design method proposed in this paper has integral stability.Consid-ering the impact of altitude and Mach number on turboprop engines,a linear feedforward control method based on the transfer function matrix is further proposed based on the centralized PI con-troller,and the stability of the entire comprehensive control method is proved.Finally,to ensure the safe and effective operation of the turboprop engine,a temperature and torque limiting protection controller is designed for the turboprop engine.Simulation results show that the centralized PI con-troller design method and linear feedforward control method proposed can effectively improve the control quality of turboprop engine control systems.
文摘In this paper, the dynamic observer-based controller design for a class of neutral systems with H∞ control is considered. An observer-based output feedback is derived for systems with polytopic parameter uncertainties. This controller assures delay-dependent stabilization and H∞ norm bound attenuation from the disturbance input to the controlled output. Numerical examples are provided for illustration and comparison of the proposed conditions.
基金The study was partially funded by the JSPS Grants-in-Aid for Challenging Exploratory Research(No.23656292)and by grants from Japan Science and Technology Agency for“Evaluation and Mitigation of Environment Impacts of Earthquake and Typhoon Disaster on Urban Area and Infrastructures”(Project Title:Refined Analysis and Damage Control of Earthquake Disaster Impact on Bridge Structures),under the Strategic Japanese-Chinese Cooperative Program on Science and Technology(S&T)for Environmental Conservation and Construction of a Society with Less Environmental Burden.
文摘The objective of the present study is to analytically investigate temperature effects of an axial-type seismic damper made of shape memory alloys(SMAs)equipped in steel frames.Based on a modified multilinear one dimensional constitutive model of SMAs,two types of SMAs are employed,which have different stress plateau and different stress growth rate with temperature increase.Temperature effects of SMA dampers on seismic performance upgrading are discussed in three aspects:different environment temperatures;rapid loading rate induced heat generation and different SMA fractions.The analysis indicates that the effect of environment temperature should be considered for the SMA damper in steel frames.However,the rapid loading rate induced heat generation has little adverse effect.
基金Supported by the National Natural Science Foundation of China (Grant Nos. 60574055, 60874073)the Specialized Research Fund for Doctoral Program of Higher Education of China (Grant No. 20050056037)the Tianjin Science and Technology Keystone Project (Grant No.08ZCKFJC27900)
文摘An iterative identification and control design method based on v-gap is given to ensure the stability of closed-loop system and control performance improvement. The whole iterative procedure includes three parts： the optimal excitation signals design, the uncertainty model set identification and the stable controller design. Firstly the worst case v-gap is used as the criterion of the optimal excitation signals design, and the design is performed via the power spectrum optimization. And then, an uncertainty model set is attained by system identification on the basis of the measure signals. The controller is designed to ensure the stability of closed-loop system and the closed-loop performance improvement. Simulation result shows that the proposed method has good convergence and closed-loop control performance.
基金This research was supported by National Key R&D Program of China:Gravitational Wave Detection Project,China(Nos.2021YFC2202601,2021YFC2202603)National Natural Science Foundation of China(No.12172288).
文摘The Drag-Free and Attitude Control System(DFACS)is a critical platform for various space missions,including high precision satellite navigation,geoscience and gravity field measurement,and space scientific experiments.This paper presents a comprehensive review of over sixty years of research on the design and dynamics model of DFACS.Firstly,we examine the open literature on DFACS and its applications in Drag-Free missions,providing readers with necessary background information on the field.Secondly,we analyze the system configurations and main characteristics of different DFACSs,paying particular attention to the coupling mechanism between the system configuration and dynamics model.Thirdly,we summarize the dynamics modeling methods and main dynamics models of DFACS from multiple perspectives,including common fundamentals and specific applications.Lastly,we identify current challenges and technological difficulties in the system design and dynamics modeling of DFACS,while suggesting potential avenues for future research.This paper aims to provide readers with a comprehensive understanding of the state-of-the-art in DFACS research,as well as the future prospects and challenges in this field.
文摘This article proposes a novel approach combining exponential-reaching-law-based equivalent control law with radial basis function (RBF) network-based switching law to strengthen the sliding mode control (SMC) tracking capacity for systems with uncertainties and disturbances. First, SMC discrete equivalent control law is designed on the basis of the nominal model of the system and the adaptive exponential reaching law, and subsequently, stability of the algorithm is analyzed. Second, RBF network is used to f...
基金The study was supported in part by grants from the Advanced Research Center for Seismic Experiments and Computations,Meijo University.
文摘This paper focuses on damage control design of SMA dampers in steel frame piers.A parametric study based on time history analyses is carried out on frametyped bridge piers with axial-type SMA damping device.The parameters examined are design parameters of strength ratioαF and stiffness ratioαK.Seismic performance indexes on displacement and strain are investigated under three JRA recommended Level 2 Ground TypeПstrong earthquake motions.Design recommendations are suggested following the results of the parametric study.
