A dynamics-based adaptive control approach is proposed for a planar dual-arm space robot in the presence of closed-loop constraints and uncertain inertial parameters of the payload. The controller is capable of contro...A dynamics-based adaptive control approach is proposed for a planar dual-arm space robot in the presence of closed-loop constraints and uncertain inertial parameters of the payload. The controller is capable of controlling the po- sition and attitude of both the satellite base and the payload grasped by the manipulator end effectors. The equations of motion in reduced-order form for the constrained system are derived by incorporating the constraint equations in terms of accelerations into Kane＇s equations of the unconstrained system. Model analysis shows that the resulting equations perfectly meet the requirement of adaptive controller design. Consequently, by using an indirect approach, an adaptive control scheme is proposed to accomplish position/attitude trajectory tracking control with the uncertain parameters be- ing estimated on-line. The actuator redundancy due to the closed-loop constraints is utilized to minimize a weighted norm of the joint torques. Global asymptotic stability is proven by using Lyapunov＇s method, and simulation results are also presented to demonstrate the effectiveness of the proposed approach.展开更多
A closed-loop control allocation method is proposed for a class of aircraft with multiple actuators. Nonlinear dynamic inversion is used to design the baseline attitude controller and derive the desired moment increme...A closed-loop control allocation method is proposed for a class of aircraft with multiple actuators. Nonlinear dynamic inversion is used to design the baseline attitude controller and derive the desired moment increment. And a feedback loop for the moment increment produced by the deflections of actuators is added to the angular rate loop, then the error between the desired and actual moment increment is the input of the dynamic control allocation. Subsequently, the stability of the closed-loop dynamic control allocation system is analyzed in detail. Especially, the closedloop system stability is also analyzed in the presence of two types of actuator failures： loss of effectiveness and lock-in-place actuator failures, where a fault detection subsystem to identify the actuator failures is absent. Finally, the proposed method is applied to a canard rotor/wing （CRW） aircraft model in fixed-wing mode, which has multiple actuators for flight control. The nonlinear simulation demonstrates that this method can guarantee the stability and tracking performance whether the actuators are healthy or fail.展开更多
After building a dynamic evolutionary game model, the essay studies the stability of the equilibrium in the game between the commercial banks and the closed-loop supply chain(CLSC) enterprises. By design of systematic...After building a dynamic evolutionary game model, the essay studies the stability of the equilibrium in the game between the commercial banks and the closed-loop supply chain(CLSC) enterprises. By design of systematic mechanism based on system dynamics theory, capital chains of independent small and medium-sized enterprises(SMEs) on CLSC are organically linked together. Moreover, a comparative simulation is studied for the previous independent and post-design dependent systems. The study shows that with business expanding and market risk growing, the independent finance chains of SMEs on CLSC often take on a certain vulnerability, while the SMEs closed-loop supply chain finance system itself is with a strong rigidity and concerto.展开更多
A class of closed-loop supply chain system consisting of one manufacturer and one supplier is designed, in which re-distribution, remanufacturing and reuse are considered synthetically. The manufacturer is in charge o...A class of closed-loop supply chain system consisting of one manufacturer and one supplier is designed, in which re-distribution, remanufacturing and reuse are considered synthetically. The manufacturer is in charge of recollecting and re-disposal the used products. Demands of ultimate products and collecting quantity of used products are described as the function of prices and reference prices. A non-linear dynamic pricing model for this closed-loop supply chain is established. A numerical example is designed, and the results of this example verified the model’s validity to price for the operation of closed-loop supply chain system.展开更多
A dynamic marine propeller simulation system was developed, which is utilized for meeting the experimental requirement of theory research and engineering design of marine electric propulsion system. By applying an act...A dynamic marine propeller simulation system was developed, which is utilized for meeting the experimental requirement of theory research and engineering design of marine electric propulsion system. By applying an actual ship parameter and its accurate propeller J＇ -KT＇ and J＇ - Kp＇ curve data, functional experiments based on the simulation system were carried out. The experiment results showed that the system can correctly emulate the propeller characteristics, produce the dynamic and steady performances of the propeller under different navigation modes, and present actual load torque for electric propulsion motor.展开更多
Conventional thermosetting plastics have faced the dilemma of non-degradability and recycling,leading to waste accumulation and a huge burden on the global environment and economy.Realizing recycling,reusing and repur...Conventional thermosetting plastics have faced the dilemma of non-degradability and recycling,leading to waste accumulation and a huge burden on the global environment and economy.Realizing recycling,reusing and repurposing plastics is a meaningful mileage for the development of sustainable ecological energy.Closed-loop recycling represents an emerging strategy for achieving the circular“waste-to-starting value-to-polymeric plastics”in recent years.Dynamic covalent chemistry(DCC)offers an attractive and efficient targeted design concept for closed-loop recyclable thermosetting polymers.In this review,the features and mechanisms of various DCC including Schiff bases,B-O bonds,sulfide-or selenide-based linkages,acetal linkages,etc.,are discussed in the construction of recyclable polymers.Based on the reversible cleavage and reformation of dynamic covalent bonds,chemically closed-loop recyclable polymers with multi-functions have been raised and developed as promising circular materials.Furthermore,we highlight and analyze the process,conditions and mechanisms of the depolymerization of polymers and recovery of monomers,as well as the remanufacture of cycled polymer networks.Significantly,the reported closed-loop recyclable thermosetting polymers exhibit potential applications in multiple fields,while providing an advanced aspect for resolving plastic waste pollution and promoting the circularity in polymeric materials.Finally,existing challenges and opportunities such as the limited production process,high costs,harsh recycling conditions,and the maintenance of comprehensive performance of thermosetting polymers in the process of implementing the practical use are proposed and discussed.展开更多
With the increasing consumption of non renewable resources such as oil,the traditional polymer manufacturing industry that relies on fossil resources is facing unprecedented challenges.The design,synthesis,and recycli...With the increasing consumption of non renewable resources such as oil,the traditional polymer manufacturing industry that relies on fossil resources is facing unprecedented challenges.The design,synthesis,and recycling of renewable and environmentally friendly bio-based polymers as alternatives to petroleum based polymers have become hot topics in research and industrial fields.Biomass has been used as a raw material to design and synthesize closed-loop recyclable polymers,which is of great significance in addressing the waste of resources and negative impact on the environment in the traditional polymer preparation process.This review summarized recent advances in the design,synthesis,and properties of closed-loop recyclable bio-based polymers,focusing on the sustainability and recyclability of bio-based materials,followed by a brief discussion of the potential applications of closed-loop recyclable bio-based polymers in emerging applications such as 3D printing and friction electric nanogenerators.In addition,perspectives and recommendations for future research on closedloop recyclable bio-based polymers were presented.展开更多
Passive control is the most popular methodology for flexible spacecraft while it remains an open problem whether the closed-loop performance can be achieved only with passive control subject to the coupling modes of r...Passive control is the most popular methodology for flexible spacecraft while it remains an open problem whether the closed-loop performance can be achieved only with passive control subject to the coupling modes of rigid and flexibility.Also,the closed-loop performance of passive PD control based on the dynamics of the Euler angle parameterization of spacecraft,which has been widely used in practice,is yet to be addressed.Towards these challenges,by introducing the input-output exact linearization theory and Lyapunov theory,the authors show that the closed-loop performance for flexible spacecraft with rigid and flexible modes can be achieved by adjusting the parameters of the passive controllers sufficiently large.This is done by firstly transforming the flexible spacecraft dynamics into an exact feedback linearization standard form,and then analyzing the closed-loop performance of flexible spacecraft.展开更多
As a type of hydraulic rotary actuator,a helical hydraulic rotary actuator exhibits a large angle,high torque,and compact structure;hence,it has been widely used in various fields.However,its core technology is propri...As a type of hydraulic rotary actuator,a helical hydraulic rotary actuator exhibits a large angle,high torque,and compact structure;hence,it has been widely used in various fields.However,its core technology is proprietary to several companies and thus has not been disclosed.Furthermore,the relevant reports are primarily limited to the component level.The dynamic characteristics of the output when a helical rotary actuator is applied to a closed-loop system are investigated from the perspective of driving system design.Two main aspects are considered:one is to establish a reliable mathematical model and the other is to consider the effect of system parameter perturbation on the output.In this study,a detailed mechanical analysis of a helical rotary hydraulic cylinder is first performed,factors such as friction and load are considered,and an accurate dynamic model of the actuator is established.Subsequently,considering the nonlinear characteristics of pressure flow and the dynamic characteristics of the valve,a dynamic model of a valve-controlled helical rotary actuator angle closed-loop system is described based on sixth-order nonlinear state equations,which has never been reported previously.After deriving the system model,a sensitivity analysis of 23 main parameters in the model with a perturbation of 10%is performed under nine operating conditions.Finally,the system dynamics model and sensitivity analysis results are verified via a prototype experiment and co-simulation,which demonstrate the reliability of the theoretical results obtained in this study.The results provide an accurate mathematical model and analysis basis for the structural optimization or control compensation of similar systems.展开更多
With the increasing scale of information technology(IT)service system,traditional thresholdbased static service level management(SLM)solution appears to be inadequate to meet current increasingly management requiremen...With the increasing scale of information technology(IT)service system,traditional thresholdbased static service level management(SLM)solution appears to be inadequate to meet current increasingly management requirement of SLM.Due to the stochastic service request rate,the random inherent failure and load surge of IT devices during service operating stage of large scaled IT system,service level objective(SLO)maintenance issue has become a realistic and important issue in dynamic SLM.This paper proposes a closed-loop feedback control mechanism to adaptively maintain SLO that service provider(SP)guaranteed at service operation stage.The mechanism can automatically tune the capacity of IT infrastructure according to service performance dispersion and reduce SLO violations.Considering that the tuning operations also affect service performance,fuzzy control is applied to alleviate the negative effect caused by tuning operations.In the dynamic SLM system that is applied with this mechanism compared with the traditional threshold-based solution,it is proved that the amount of SLO violations obviously decreases,the reliability of the service system increases relatively,and the resource utilization of IT infrastructure is optimized.展开更多
The paper presents a preview controller design for ATS （active trailer steering） systems to improve high-speed stability of AHVs （articulated heavy vehicles）. An AHV consists of a towing unit, namely tractor or tr...The paper presents a preview controller design for ATS （active trailer steering） systems to improve high-speed stability of AHVs （articulated heavy vehicles）. An AHV consists of a towing unit, namely tractor or truck, and one or more towed units which called trailers. Individual units are connected to one another at articulated joints by mechanical couplings. Due to the multi-unit configurations, AHVs exhibit unique unstable motion modes, including jack-knifing, trailer swing and rollover. These unstable motion modes are the leading cause of highway accidents. To prevent these unstable motion modes, the preview controller, namely the LPDP （lateral position deviation preview） controller, is proposed. For a truck/full-trailer combination, the LPDP controller is designed to control the steering of the front and rear axle wheels of the trailing unit. The calculation of the corrective steering angle of the trailer front axle wheels is based on the preview information of the lateral position deviation of the trajectory of the axle center from that of the truck front axle center. Similarly, the steering angle of the trailer rear axle wheels is calculated by using the lateral position deviation of the trajectory of the axle center from that of the truck front axle. To perform closed-loop dynamic simulations and evaluate the vehicle performance measure, a driver model is introduced and it ＇derives＇ the AHV model based on well-defined testing specifications. The proposed preview control scheme in the continuous time domain is developed by using the LQR （linear quadratic regular） technique. The closed-loop simulation results indicate that the performance of the AHV with the LPDP controller is improved by decreasing rearward amplification ratio from the baseline value of 1.28 to 0.98 and reducing transient off-tracking by 95.03%. The proposed LPDP control algorithm provides an alternative method for the design optimization of AHVs with ATS systems.展开更多
基金supported by the National Natural Science Foundation of China(11272027)
文摘A dynamics-based adaptive control approach is proposed for a planar dual-arm space robot in the presence of closed-loop constraints and uncertain inertial parameters of the payload. The controller is capable of controlling the po- sition and attitude of both the satellite base and the payload grasped by the manipulator end effectors. The equations of motion in reduced-order form for the constrained system are derived by incorporating the constraint equations in terms of accelerations into Kane＇s equations of the unconstrained system. Model analysis shows that the resulting equations perfectly meet the requirement of adaptive controller design. Consequently, by using an indirect approach, an adaptive control scheme is proposed to accomplish position/attitude trajectory tracking control with the uncertain parameters be- ing estimated on-line. The actuator redundancy due to the closed-loop constraints is utilized to minimize a weighted norm of the joint torques. Global asymptotic stability is proven by using Lyapunov＇s method, and simulation results are also presented to demonstrate the effectiveness of the proposed approach.
基金Program for New Century Excellent Talents in University (NCET-10-0032)
文摘A closed-loop control allocation method is proposed for a class of aircraft with multiple actuators. Nonlinear dynamic inversion is used to design the baseline attitude controller and derive the desired moment increment. And a feedback loop for the moment increment produced by the deflections of actuators is added to the angular rate loop, then the error between the desired and actual moment increment is the input of the dynamic control allocation. Subsequently, the stability of the closed-loop dynamic control allocation system is analyzed in detail. Especially, the closedloop system stability is also analyzed in the presence of two types of actuator failures： loss of effectiveness and lock-in-place actuator failures, where a fault detection subsystem to identify the actuator failures is absent. Finally, the proposed method is applied to a canard rotor/wing （CRW） aircraft model in fixed-wing mode, which has multiple actuators for flight control. The nonlinear simulation demonstrates that this method can guarantee the stability and tracking performance whether the actuators are healthy or fail.
基金the Natural Science Research Fund of Hubei Province(No.2014BDH121)
文摘After building a dynamic evolutionary game model, the essay studies the stability of the equilibrium in the game between the commercial banks and the closed-loop supply chain(CLSC) enterprises. By design of systematic mechanism based on system dynamics theory, capital chains of independent small and medium-sized enterprises(SMEs) on CLSC are organically linked together. Moreover, a comparative simulation is studied for the previous independent and post-design dependent systems. The study shows that with business expanding and market risk growing, the independent finance chains of SMEs on CLSC often take on a certain vulnerability, while the SMEs closed-loop supply chain finance system itself is with a strong rigidity and concerto.
文摘A class of closed-loop supply chain system consisting of one manufacturer and one supplier is designed, in which re-distribution, remanufacturing and reuse are considered synthetically. The manufacturer is in charge of recollecting and re-disposal the used products. Demands of ultimate products and collecting quantity of used products are described as the function of prices and reference prices. A non-linear dynamic pricing model for this closed-loop supply chain is established. A numerical example is designed, and the results of this example verified the model’s validity to price for the operation of closed-loop supply chain system.
基金supported by the Fund of Shanghai Committee of Science and Technology(Grant No.11170501700)the International Cooperation and Exchange Projects of the Ministry of Science and Technology(Grant No.2012DFG71850)
文摘A dynamic marine propeller simulation system was developed, which is utilized for meeting the experimental requirement of theory research and engineering design of marine electric propulsion system. By applying an actual ship parameter and its accurate propeller J＇ -KT＇ and J＇ - Kp＇ curve data, functional experiments based on the simulation system were carried out. The experiment results showed that the system can correctly emulate the propeller characteristics, produce the dynamic and steady performances of the propeller under different navigation modes, and present actual load torque for electric propulsion motor.
基金supported by the National Key Research and Development Program of China(2022YFB3808800)the National Natural Science Foundation of China(52272084,52072177,22401150)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20241448)the Fundamental Research Funds for the Central Universities(2023102003,30924010811).
文摘Conventional thermosetting plastics have faced the dilemma of non-degradability and recycling,leading to waste accumulation and a huge burden on the global environment and economy.Realizing recycling,reusing and repurposing plastics is a meaningful mileage for the development of sustainable ecological energy.Closed-loop recycling represents an emerging strategy for achieving the circular“waste-to-starting value-to-polymeric plastics”in recent years.Dynamic covalent chemistry(DCC)offers an attractive and efficient targeted design concept for closed-loop recyclable thermosetting polymers.In this review,the features and mechanisms of various DCC including Schiff bases,B-O bonds,sulfide-or selenide-based linkages,acetal linkages,etc.,are discussed in the construction of recyclable polymers.Based on the reversible cleavage and reformation of dynamic covalent bonds,chemically closed-loop recyclable polymers with multi-functions have been raised and developed as promising circular materials.Furthermore,we highlight and analyze the process,conditions and mechanisms of the depolymerization of polymers and recovery of monomers,as well as the remanufacture of cycled polymer networks.Significantly,the reported closed-loop recyclable thermosetting polymers exhibit potential applications in multiple fields,while providing an advanced aspect for resolving plastic waste pollution and promoting the circularity in polymeric materials.Finally,existing challenges and opportunities such as the limited production process,high costs,harsh recycling conditions,and the maintenance of comprehensive performance of thermosetting polymers in the process of implementing the practical use are proposed and discussed.
基金Natural Science Foundation of China(Grant Nos.32471815 and 32401528)Natural Science Foundation of Jiangsu Province of China(Grant Nos.BK20241745 and BK20240294).
文摘With the increasing consumption of non renewable resources such as oil,the traditional polymer manufacturing industry that relies on fossil resources is facing unprecedented challenges.The design,synthesis,and recycling of renewable and environmentally friendly bio-based polymers as alternatives to petroleum based polymers have become hot topics in research and industrial fields.Biomass has been used as a raw material to design and synthesize closed-loop recyclable polymers,which is of great significance in addressing the waste of resources and negative impact on the environment in the traditional polymer preparation process.This review summarized recent advances in the design,synthesis,and properties of closed-loop recyclable bio-based polymers,focusing on the sustainability and recyclability of bio-based materials,followed by a brief discussion of the potential applications of closed-loop recyclable bio-based polymers in emerging applications such as 3D printing and friction electric nanogenerators.In addition,perspectives and recommendations for future research on closedloop recyclable bio-based polymers were presented.
基金supported by the National Key RδD Program of China under Grant No.2018YFA0703800the Science and Technology on Space Intelligent Control Laboratory Foundation of China under Grant No.ZDSYS-2018-04the National Natural Science Foundation of China under Grant Nos.51805025 and 61673350。
文摘Passive control is the most popular methodology for flexible spacecraft while it remains an open problem whether the closed-loop performance can be achieved only with passive control subject to the coupling modes of rigid and flexibility.Also,the closed-loop performance of passive PD control based on the dynamics of the Euler angle parameterization of spacecraft,which has been widely used in practice,is yet to be addressed.Towards these challenges,by introducing the input-output exact linearization theory and Lyapunov theory,the authors show that the closed-loop performance for flexible spacecraft with rigid and flexible modes can be achieved by adjusting the parameters of the passive controllers sufficiently large.This is done by firstly transforming the flexible spacecraft dynamics into an exact feedback linearization standard form,and then analyzing the closed-loop performance of flexible spacecraft.
基金National Natural Science Foundation of China(Grant No.51922093)Scientific Research Fund of Zhejiang Provincial Education Department of China(Grant No.Y202148352)Major Science and Technology Projects in Ningbo of China(Grant No.2019B10054).
文摘As a type of hydraulic rotary actuator,a helical hydraulic rotary actuator exhibits a large angle,high torque,and compact structure;hence,it has been widely used in various fields.However,its core technology is proprietary to several companies and thus has not been disclosed.Furthermore,the relevant reports are primarily limited to the component level.The dynamic characteristics of the output when a helical rotary actuator is applied to a closed-loop system are investigated from the perspective of driving system design.Two main aspects are considered:one is to establish a reliable mathematical model and the other is to consider the effect of system parameter perturbation on the output.In this study,a detailed mechanical analysis of a helical rotary hydraulic cylinder is first performed,factors such as friction and load are considered,and an accurate dynamic model of the actuator is established.Subsequently,considering the nonlinear characteristics of pressure flow and the dynamic characteristics of the valve,a dynamic model of a valve-controlled helical rotary actuator angle closed-loop system is described based on sixth-order nonlinear state equations,which has never been reported previously.After deriving the system model,a sensitivity analysis of 23 main parameters in the model with a perturbation of 10%is performed under nine operating conditions.Finally,the system dynamics model and sensitivity analysis results are verified via a prototype experiment and co-simulation,which demonstrate the reliability of the theoretical results obtained in this study.The results provide an accurate mathematical model and analysis basis for the structural optimization or control compensation of similar systems.
基金Acknowledgements This work was partly supported by the State Key Development Program for Basic Research of China(No.2007CB310703)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(Grant No.60821001)the National High Technology Research and Development Program of China(No.2008AA01Z201).
文摘With the increasing scale of information technology(IT)service system,traditional thresholdbased static service level management(SLM)solution appears to be inadequate to meet current increasingly management requirement of SLM.Due to the stochastic service request rate,the random inherent failure and load surge of IT devices during service operating stage of large scaled IT system,service level objective(SLO)maintenance issue has become a realistic and important issue in dynamic SLM.This paper proposes a closed-loop feedback control mechanism to adaptively maintain SLO that service provider(SP)guaranteed at service operation stage.The mechanism can automatically tune the capacity of IT infrastructure according to service performance dispersion and reduce SLO violations.Considering that the tuning operations also affect service performance,fuzzy control is applied to alleviate the negative effect caused by tuning operations.In the dynamic SLM system that is applied with this mechanism compared with the traditional threshold-based solution,it is proved that the amount of SLO violations obviously decreases,the reliability of the service system increases relatively,and the resource utilization of IT infrastructure is optimized.
文摘The paper presents a preview controller design for ATS （active trailer steering） systems to improve high-speed stability of AHVs （articulated heavy vehicles）. An AHV consists of a towing unit, namely tractor or truck, and one or more towed units which called trailers. Individual units are connected to one another at articulated joints by mechanical couplings. Due to the multi-unit configurations, AHVs exhibit unique unstable motion modes, including jack-knifing, trailer swing and rollover. These unstable motion modes are the leading cause of highway accidents. To prevent these unstable motion modes, the preview controller, namely the LPDP （lateral position deviation preview） controller, is proposed. For a truck/full-trailer combination, the LPDP controller is designed to control the steering of the front and rear axle wheels of the trailing unit. The calculation of the corrective steering angle of the trailer front axle wheels is based on the preview information of the lateral position deviation of the trajectory of the axle center from that of the truck front axle center. Similarly, the steering angle of the trailer rear axle wheels is calculated by using the lateral position deviation of the trajectory of the axle center from that of the truck front axle. To perform closed-loop dynamic simulations and evaluate the vehicle performance measure, a driver model is introduced and it ＇derives＇ the AHV model based on well-defined testing specifications. The proposed preview control scheme in the continuous time domain is developed by using the LQR （linear quadratic regular） technique. The closed-loop simulation results indicate that the performance of the AHV with the LPDP controller is improved by decreasing rearward amplification ratio from the baseline value of 1.28 to 0.98 and reducing transient off-tracking by 95.03%. The proposed LPDP control algorithm provides an alternative method for the design optimization of AHVs with ATS systems.
