As a typical energetic composite,polytetrafluoroethylene(PTFE)/aluminum(Al)has been widely applied in explosives,pyrotechnics,and propellants due to its ultra-high energy density and intense exothermic reaction.In thi...As a typical energetic composite,polytetrafluoroethylene(PTFE)/aluminum(Al)has been widely applied in explosives,pyrotechnics,and propellants due to its ultra-high energy density and intense exothermic reaction.In this work,the radial gradient(RG)structure of PTFE/Al cylinders with three different PTFE morphologies(200 nm and 5μm particles and 5μm fiber)and content changes are prepared by 3D printing technology.The effect of radial gradient structure on the pressure output of PTFE/Al has been studied.Compared with the morphology change of PTFE,the change of component content in the gradient structure has an obvious effect on the pressure output of the PTFE/Al cylinder.Furthermore,the relationships of the morphology,content of PTFE and the combustion reaction of the PTFE/Al cylinder reveal that the cylinder shows a more complex flame propagation process than others.These results could provide a strategy to improve the combustion and pressure output of PTFE/Al.展开更多
Transient performance for output regulation problems of linear discrete-time systems with input saturation is addressed by using the composite nonlinear feedback（CNF） control technique. The regulator is designed to ...Transient performance for output regulation problems of linear discrete-time systems with input saturation is addressed by using the composite nonlinear feedback（CNF） control technique. The regulator is designed to be an additive combination of a linear regulator part and a nonlinear feedback part. The linear regulator part solves the regulation problem independently which produces a quick output response but large oscillations. The nonlinear feedback part with well-tuned parameters is introduced to improve the transient performance by smoothing the oscillatory convergence. It is shown that the introduction of the nonlinear feedback part does not change the solvability conditions of the linear discrete-time output regulation problem. The effectiveness of transient improvement is illustrated by a numeric example.展开更多
Composite nonlinear feedback （CNF） control techniquefor tracking control problems is extended to the output regulationproblem of singular linear systems with input saturation. A statefeedback CNF control law and an ...Composite nonlinear feedback （CNF） control techniquefor tracking control problems is extended to the output regulationproblem of singular linear systems with input saturation. A statefeedback CNF control law and an output feedback CNF controllaw are constructed respectively for the output regulation problemof singular linear systems with input saturation. It is shown thatthe output regulation problem by CNF control is solvable underthe same solvability conditions of the output regulation problemby linear control. However, with the virtue of the CNF control, thetransient performance of the closed-loop system can be improvedby carefully designing the linear part and the nonlinear part of theCNF control law. The design procedure and the improvement ofthe transient performance of the closed-loop system are illustratedwith a numerical simulation.展开更多
This paper investigates the cooperative output regulation problem of linear multi-agent systems with a linear exogenous system(exo-system).The network topology is described by a directed graph which contains a directe...This paper investigates the cooperative output regulation problem of linear multi-agent systems with a linear exogenous system(exo-system).The network topology is described by a directed graph which contains a directed spanning tree with the exo-system as the root.Aiming at improving the transient performance of the multi-agent systems,a dynamic control law is developed by the composite nonlinear feedback(CNF)control technique.In particular,a distributed dynamic compensator independent of the interaction on the compensator states of agents among the network,is adopted.The solvability condition for the cooperative output regulation problem is obtained using the small-gain theory,which will not be destroyed by adding the nonlinear feedback part of the CNF control law.It is also shown that in the case with the exo-system not diverging exponentially,the small-gain condition can be guaranteed using the low-gain design.Finally,simulation results illustrate that the proposed CNF control law improves the transient performance for the cooperative output regulation of linear multi-agent systems.展开更多
We report on the design, realization, and output performance of a diode-pumped high-peak-power passively Q-switched Nd:YAG∕Cr^(4+):YAG composite medium monolithic laser with four-beam output. The energy of a laser pu...We report on the design, realization, and output performance of a diode-pumped high-peak-power passively Q-switched Nd:YAG∕Cr^(4+):YAG composite medium monolithic laser with four-beam output. The energy of a laser pulse was higher than 3 m J with duration of 0.9 ns. The proposed system has the ability to choose independently the focus of each beam. Such a laser device can be used for multipoint ignition of an automobile gasoline engine, but could also be of interest for ignition in space propulsion or in turbulent conditions specific to aeronautics.展开更多
离子聚合物金属复合材料IPMC(Ion-exchange polymer metal composite,IPMC)具有驱动和传感功能。本文利用IPMC的传感能力,设计了一种海流速度信息传感器,基于3种模型分别使用ANSYS和MATLAB软件对不同条件的情况进行仿真,并设计测试系统...离子聚合物金属复合材料IPMC(Ion-exchange polymer metal composite,IPMC)具有驱动和传感功能。本文利用IPMC的传感能力,设计了一种海流速度信息传感器,基于3种模型分别使用ANSYS和MATLAB软件对不同条件的情况进行仿真,并设计测试系统进行实验,分析验证了片状IPMC在均匀流速下的传感能力。研究结果表明:片状IPMC的初始稳定电压以及测量灵敏度均与材料面积正相关;随着流速的增大,IPMC达到稳定输出电压的时间缩短,且材料输出电压在达到稳定前与时间呈现二次多项式函数关系,函数最大值即为实验所测得的稳定输出电压;各组次实验的重复性良好。展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11872341 and 22075261)。
文摘As a typical energetic composite,polytetrafluoroethylene(PTFE)/aluminum(Al)has been widely applied in explosives,pyrotechnics,and propellants due to its ultra-high energy density and intense exothermic reaction.In this work,the radial gradient(RG)structure of PTFE/Al cylinders with three different PTFE morphologies(200 nm and 5μm particles and 5μm fiber)and content changes are prepared by 3D printing technology.The effect of radial gradient structure on the pressure output of PTFE/Al has been studied.Compared with the morphology change of PTFE,the change of component content in the gradient structure has an obvious effect on the pressure output of the PTFE/Al cylinder.Furthermore,the relationships of the morphology,content of PTFE and the combustion reaction of the PTFE/Al cylinder reveal that the cylinder shows a more complex flame propagation process than others.These results could provide a strategy to improve the combustion and pressure output of PTFE/Al.
基金supported by the National Natural Science Foundation of China(61074004)the Research Fund for the Doctoral Program of Higher Education(20110121110017)
文摘Transient performance for output regulation problems of linear discrete-time systems with input saturation is addressed by using the composite nonlinear feedback（CNF） control technique. The regulator is designed to be an additive combination of a linear regulator part and a nonlinear feedback part. The linear regulator part solves the regulation problem independently which produces a quick output response but large oscillations. The nonlinear feedback part with well-tuned parameters is introduced to improve the transient performance by smoothing the oscillatory convergence. It is shown that the introduction of the nonlinear feedback part does not change the solvability conditions of the linear discrete-time output regulation problem. The effectiveness of transient improvement is illustrated by a numeric example.
基金supported by the National Natural Science Foundation of China(61374035)
文摘Composite nonlinear feedback （CNF） control techniquefor tracking control problems is extended to the output regulationproblem of singular linear systems with input saturation. A statefeedback CNF control law and an output feedback CNF controllaw are constructed respectively for the output regulation problemof singular linear systems with input saturation. It is shown thatthe output regulation problem by CNF control is solvable underthe same solvability conditions of the output regulation problemby linear control. However, with the virtue of the CNF control, thetransient performance of the closed-loop system can be improvedby carefully designing the linear part and the nonlinear part of theCNF control law. The design procedure and the improvement ofthe transient performance of the closed-loop system are illustratedwith a numerical simulation.
基金This work was supported in part by the National Natural Science Foundation of China under Grants 62273285 and 62173283in part by the Natural Science Foundation of Fujian Province of China under Grants 2021J01051.
文摘This paper investigates the cooperative output regulation problem of linear multi-agent systems with a linear exogenous system(exo-system).The network topology is described by a directed graph which contains a directed spanning tree with the exo-system as the root.Aiming at improving the transient performance of the multi-agent systems,a dynamic control law is developed by the composite nonlinear feedback(CNF)control technique.In particular,a distributed dynamic compensator independent of the interaction on the compensator states of agents among the network,is adopted.The solvability condition for the cooperative output regulation problem is obtained using the small-gain theory,which will not be destroyed by adding the nonlinear feedback part of the CNF control law.It is also shown that in the case with the exo-system not diverging exponentially,the small-gain condition can be guaranteed using the low-gain design.Finally,simulation results illustrate that the proposed CNF control law improves the transient performance for the cooperative output regulation of linear multi-agent systems.
基金Autoritatea Nationala pentru Cercetare Stiintifica(ANCS)(PN-II-PT-PCCA-2011-3.2-1040(58/2012),NUCLEU4N/2016)Horizon 2020(691688 LASIG-TWIN)
文摘We report on the design, realization, and output performance of a diode-pumped high-peak-power passively Q-switched Nd:YAG∕Cr^(4+):YAG composite medium monolithic laser with four-beam output. The energy of a laser pulse was higher than 3 m J with duration of 0.9 ns. The proposed system has the ability to choose independently the focus of each beam. Such a laser device can be used for multipoint ignition of an automobile gasoline engine, but could also be of interest for ignition in space propulsion or in turbulent conditions specific to aeronautics.
文摘离子聚合物金属复合材料IPMC(Ion-exchange polymer metal composite,IPMC)具有驱动和传感功能。本文利用IPMC的传感能力,设计了一种海流速度信息传感器,基于3种模型分别使用ANSYS和MATLAB软件对不同条件的情况进行仿真,并设计测试系统进行实验,分析验证了片状IPMC在均匀流速下的传感能力。研究结果表明:片状IPMC的初始稳定电压以及测量灵敏度均与材料面积正相关;随着流速的增大,IPMC达到稳定输出电压的时间缩短,且材料输出电压在达到稳定前与时间呈现二次多项式函数关系,函数最大值即为实验所测得的稳定输出电压;各组次实验的重复性良好。
