Based on generalized the variation method, by introducing Hamilton function and Lagrange multiplier, this paper proposed a linear quadratic optimal control strategy for an incomplete controllable system with fixed ter...Based on generalized the variation method, by introducing Hamilton function and Lagrange multiplier, this paper proposed a linear quadratic optimal control strategy for an incomplete controllable system with fixed terminal state and time. Applying the proposed optimal control to the simple two-input dual-stage actuator magnetic head positioning system with three degrees-of-freedom, the simulation results show that the system has no residual vibration at the terminal position and time, which can reduce the total access time during head positioning process. To verify the validation of the optimal control strategy of three degrees-of-freedom spring-mass models in actual magnetic head positioning of hard disk drives, a finite element model of an actual magnetic head positioning system is presented. Substituting the optimal control force from simple three degrees-of-freedom spring-mass models into the finite element model, the simulation results show that the magnetic head also has no residual vibration at the end of track-to-track travel. That is to say, the linear quadratic optimal control technique based on simple two-input dual- stage actuator system with three degrees-of-freedom proposed in this paper is of high reliability for the industrial application of an actual magnetic head positioning system.展开更多
As a major equipment for thermal power plants,the main function of coarse powder separators is to separate particles into size groups according to particle diameter.With the rising coal prices,power plants are using m...As a major equipment for thermal power plants,the main function of coarse powder separators is to separate particles into size groups according to particle diameter.With the rising coal prices,power plants are using more low-density lignite.Consequently,the original equipment does not operate under normal conditions.Therefore,to return the equipment to normal operating conditions,the isokinetic sampling method,computational fluid dynamics(CFD),and discrete phase model(DPM)based on the Euler-Lagrange method are applied in this research to analyze the effect of baffle shapes,baffle numbers,and centrifugal blades on the equipment performance index,like R90.The shape of the baffle plate was optimized and improved.Preferential method was applied to determine the optimal number of baffles to ensure normal working conditions.Results show that curved baffles can suppress the axial negative gradient field below themselves better than rectangular baffles.The curved baffles selected by the optimal seeking method make full use of the negative axial gradient field and provide the particles entering the separation zone at tangential velocity in advance with the addition of centrifugal blades.Thus,pre-separation can be realized.The R90 is 5 at the separator outlet and 95 at the powder return port,indicating that the output capacity of the separator returned to a reasonable operating performance.展开更多
Learning and self-adaptation ability is highly required to be integrated in path planning algorithm for underwater robot during navigation through an unspecified underwater environment. High frequency oscillations dur...Learning and self-adaptation ability is highly required to be integrated in path planning algorithm for underwater robot during navigation through an unspecified underwater environment. High frequency oscillations during underwater motion are responsible for nonlinearities in dynamic behavior of underwater robot as well as uncertainties in hydrodynamic coefficients. Reactive behaviors of underwater robot are designed considering the position and orientation of both target and nearest obstacle from robot s current position. Human like reasoning power and approximation based learning skill of neural based adaptive fuzzy inference system（ANFIS）has been found to be effective for underwater multivariable motion control. More than one ANFIS models are used here for achieving goal and obstacle avoidance while avoiding local minima situation in both horizontal and vertical plane of three dimensional workspace.An error gradient approach based on input-output training patterns for learning purpose has been promoted to spawn trajectory of underwater robot optimizing path length as well as time taken. The simulation and experimental results endorse sturdiness and viability of the proposed method in comparison with other navigational methodologies to negotiate with hectic conditions during motion of underwater mobile robot.展开更多
Circularly polarized light(CPL)detectors based on chiral organic materials or inorganic structures hold great potential for highly integrated on-chip applications;however,these devices usually have to seek an optimal ...Circularly polarized light(CPL)detectors based on chiral organic materials or inorganic structures hold great potential for highly integrated on-chip applications;however,these devices usually have to seek an optimal balance among the asymmetry factor(g),responsivity(R),and stability.Here,we aim to break such a limitation by combining chiral inorganic plasmonic metamaterials with electrical gain,by which one can enhance both g and R while simultaneously securing the stability.We demonstrate a CPL detector based on"S"-shaped chiral Ag nanowires/InAs/Si heterostructures,where the meticulous construction of the"S"-shaped chiral Ag nanowires with the overlaying InAs channel enables a substantial absorption asymmetry in InAs due to differentiated localized surface plasmon resonances excited by left-and right-circularly polarized(LCP and RCP)light.The InAs serves as a conductive channel,achieving significant electrical gain through photoconductive effects assisted by photogating,gate modulation,and trap effects.The proposed inorganic stable device exhibits a high electrical g of~1.56,an ultra-high R of~33,900 A W^(-1),a large specific detectivity of~1.8×10^(11) Jones,and an ultra-short response time of~23 ns,with the high performance achieved in a broad spectral range from 2μm to 2.8μm.Ultimately,by encoding ASCII code 1 and 0 onto LCP and RCP light,respectively,and leveraging the device's heightened discrimination and response performance to these polarizations,we demonstrate a simple yet key-free optical encryption communication scheme at the device level,highlighting its extensive potential for system-level applications.展开更多
基金Project supported by the National Natural Science Foundation of China （No. 10472038）；the Science Foundation of the Ministry of Education of China for Ph.D. Programme （No. 20050730016）；the National Science Foundation of China for 0utstanding Young Researchers （No. 10025208）.
文摘Based on generalized the variation method, by introducing Hamilton function and Lagrange multiplier, this paper proposed a linear quadratic optimal control strategy for an incomplete controllable system with fixed terminal state and time. Applying the proposed optimal control to the simple two-input dual-stage actuator magnetic head positioning system with three degrees-of-freedom, the simulation results show that the system has no residual vibration at the terminal position and time, which can reduce the total access time during head positioning process. To verify the validation of the optimal control strategy of three degrees-of-freedom spring-mass models in actual magnetic head positioning of hard disk drives, a finite element model of an actual magnetic head positioning system is presented. Substituting the optimal control force from simple three degrees-of-freedom spring-mass models into the finite element model, the simulation results show that the magnetic head also has no residual vibration at the end of track-to-track travel. That is to say, the linear quadratic optimal control technique based on simple two-input dual- stage actuator system with three degrees-of-freedom proposed in this paper is of high reliability for the industrial application of an actual magnetic head positioning system.
基金supported by the Innovative Research Team of Henan Polytechnic University (T2020-3).
文摘As a major equipment for thermal power plants,the main function of coarse powder separators is to separate particles into size groups according to particle diameter.With the rising coal prices,power plants are using more low-density lignite.Consequently,the original equipment does not operate under normal conditions.Therefore,to return the equipment to normal operating conditions,the isokinetic sampling method,computational fluid dynamics(CFD),and discrete phase model(DPM)based on the Euler-Lagrange method are applied in this research to analyze the effect of baffle shapes,baffle numbers,and centrifugal blades on the equipment performance index,like R90.The shape of the baffle plate was optimized and improved.Preferential method was applied to determine the optimal number of baffles to ensure normal working conditions.Results show that curved baffles can suppress the axial negative gradient field below themselves better than rectangular baffles.The curved baffles selected by the optimal seeking method make full use of the negative axial gradient field and provide the particles entering the separation zone at tangential velocity in advance with the addition of centrifugal blades.Thus,pre-separation can be realized.The R90 is 5 at the separator outlet and 95 at the powder return port,indicating that the output capacity of the separator returned to a reasonable operating performance.
文摘Learning and self-adaptation ability is highly required to be integrated in path planning algorithm for underwater robot during navigation through an unspecified underwater environment. High frequency oscillations during underwater motion are responsible for nonlinearities in dynamic behavior of underwater robot as well as uncertainties in hydrodynamic coefficients. Reactive behaviors of underwater robot are designed considering the position and orientation of both target and nearest obstacle from robot s current position. Human like reasoning power and approximation based learning skill of neural based adaptive fuzzy inference system（ANFIS）has been found to be effective for underwater multivariable motion control. More than one ANFIS models are used here for achieving goal and obstacle avoidance while avoiding local minima situation in both horizontal and vertical plane of three dimensional workspace.An error gradient approach based on input-output training patterns for learning purpose has been promoted to spawn trajectory of underwater robot optimizing path length as well as time taken. The simulation and experimental results endorse sturdiness and viability of the proposed method in comparison with other navigational methodologies to negotiate with hectic conditions during motion of underwater mobile robot.
基金The National Natural Science Foundation of China(62105126,62120106001,and 62205227)the Natural Science Foundation of Jiangsu Province(BK20210454),the China Postdoctoral Science Foundation(2023M731449)+3 种基金the Undergraduate Training Program for Innovation and Entrepreneurship,Soochow University(202310285116Y)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(22KJB140005)the Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province,Soochow University(ZZ2311)the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions.
文摘Circularly polarized light(CPL)detectors based on chiral organic materials or inorganic structures hold great potential for highly integrated on-chip applications;however,these devices usually have to seek an optimal balance among the asymmetry factor(g),responsivity(R),and stability.Here,we aim to break such a limitation by combining chiral inorganic plasmonic metamaterials with electrical gain,by which one can enhance both g and R while simultaneously securing the stability.We demonstrate a CPL detector based on"S"-shaped chiral Ag nanowires/InAs/Si heterostructures,where the meticulous construction of the"S"-shaped chiral Ag nanowires with the overlaying InAs channel enables a substantial absorption asymmetry in InAs due to differentiated localized surface plasmon resonances excited by left-and right-circularly polarized(LCP and RCP)light.The InAs serves as a conductive channel,achieving significant electrical gain through photoconductive effects assisted by photogating,gate modulation,and trap effects.The proposed inorganic stable device exhibits a high electrical g of~1.56,an ultra-high R of~33,900 A W^(-1),a large specific detectivity of~1.8×10^(11) Jones,and an ultra-short response time of~23 ns,with the high performance achieved in a broad spectral range from 2μm to 2.8μm.Ultimately,by encoding ASCII code 1 and 0 onto LCP and RCP light,respectively,and leveraging the device's heightened discrimination and response performance to these polarizations,we demonstrate a simple yet key-free optical encryption communication scheme at the device level,highlighting its extensive potential for system-level applications.
