An impact angle constrained fuzzy adaptive fault tolerant integrated guidance and control method for Ski-to-Turn(STT)missiles subject to unsteady aerodynamics and multiple disturbances is proposed.Unsteady aerodynamic...An impact angle constrained fuzzy adaptive fault tolerant integrated guidance and control method for Ski-to-Turn(STT)missiles subject to unsteady aerodynamics and multiple disturbances is proposed.Unsteady aerodynamics appears when flight vehicles are in a transonic state or confronted with unstable airflow.Meanwhile,actuator failures and multisource model uncertainties are introduced.However,the boundaries of these multisource uncertainties are assumed unknown.The target is assumed to execute high maneuver movement which is unknown to the missile.Furthermore,impact angle constraint puts forward higher requirements for the interception accuracy of the integrated guidance and control(IGC)method.The impact angle constraint and the precise interception are established as the object of the IGC method.Then,the boundaries of the lumped disturbances are estimated,and several fuzzy logic systems are introduced to compensate the unknown nonlinearities and uncertainties.Next,a series of adaptive laws are developed so that the undesirable effects arising from unsteady aerodynamics,actuator failures and unknown uncertainties could be suppressed.Consequently,an impact angle constrained fuzzy adaptive fault tolerant IGC method with three loops is constructed and a perfect hit-to-kill interception with specified impact angle can be implemented.Eventually,the numerical simulations are conducted to verify the effectiveness and superiority of the proposed method.展开更多
Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting trigge...Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting triggers shade avoidance responses(SARs)that optimize light absorption but impair plant vigor and performance,limiting yield improvement through increasing plant density.In this study,we demonstrated that high-density-induced leaf angle narrowing and stem/stalk elongation are largely dependent on phytochrome B(phyB1/B2),the primaryphotoreceptor responsible for perceiving red(R)and far-red(FR)light in maize.We found that maize phyB physically interacts with the LIGULELESS1(LG1),a classical key regulator of leaf angle,to coordinately regulate plant architecture and density tolerance.The abundance of LG1 is significantly increased by phyB under high R:FR light(low density)but rapidly decreases under low R:FR light(high density),correlating with variations in leaf angle and plant height under various densities.In addition,we identified the homeobox transcription factor HB53 as a target co-repressed by both phyB and LG1 but rapidly induced by canopy shade.Genetic and cellular analyses showed that HB53 regulates plant architecture by controlling the elongation and division of ligular adaxial and abaxial cells.Taken together,these findings uncover the phyB-LG1-HB53 regulatory module as a key molecular mechanism governing plant architecture and density tolerance,providing potential genetic targets for breeding maize hybrid varieties suitable for high-density planting.展开更多
基金supported by the National Natural Science Foundation of China(62003264).
文摘An impact angle constrained fuzzy adaptive fault tolerant integrated guidance and control method for Ski-to-Turn(STT)missiles subject to unsteady aerodynamics and multiple disturbances is proposed.Unsteady aerodynamics appears when flight vehicles are in a transonic state or confronted with unstable airflow.Meanwhile,actuator failures and multisource model uncertainties are introduced.However,the boundaries of these multisource uncertainties are assumed unknown.The target is assumed to execute high maneuver movement which is unknown to the missile.Furthermore,impact angle constraint puts forward higher requirements for the interception accuracy of the integrated guidance and control(IGC)method.The impact angle constraint and the precise interception are established as the object of the IGC method.Then,the boundaries of the lumped disturbances are estimated,and several fuzzy logic systems are introduced to compensate the unknown nonlinearities and uncertainties.Next,a series of adaptive laws are developed so that the undesirable effects arising from unsteady aerodynamics,actuator failures and unknown uncertainties could be suppressed.Consequently,an impact angle constrained fuzzy adaptive fault tolerant IGC method with three loops is constructed and a perfect hit-to-kill interception with specified impact angle can be implemented.Eventually,the numerical simulations are conducted to verify the effectiveness and superiority of the proposed method.
基金the National Natural Science Foundation of China(32270263 to G.L.,32130077 to H.W.,and 32272140 to P.L.)the Shandong Provincial Natural Science Foundation(ZR2022QC095,ZR2020MC023,ZR2022MC019).
文摘Over the past few decades,significant improvements in maize yield have been largely attributed to increased plant density of upright hybrid varieties rather than increased yield per plant.However,dense planting triggers shade avoidance responses(SARs)that optimize light absorption but impair plant vigor and performance,limiting yield improvement through increasing plant density.In this study,we demonstrated that high-density-induced leaf angle narrowing and stem/stalk elongation are largely dependent on phytochrome B(phyB1/B2),the primaryphotoreceptor responsible for perceiving red(R)and far-red(FR)light in maize.We found that maize phyB physically interacts with the LIGULELESS1(LG1),a classical key regulator of leaf angle,to coordinately regulate plant architecture and density tolerance.The abundance of LG1 is significantly increased by phyB under high R:FR light(low density)but rapidly decreases under low R:FR light(high density),correlating with variations in leaf angle and plant height under various densities.In addition,we identified the homeobox transcription factor HB53 as a target co-repressed by both phyB and LG1 but rapidly induced by canopy shade.Genetic and cellular analyses showed that HB53 regulates plant architecture by controlling the elongation and division of ligular adaxial and abaxial cells.Taken together,these findings uncover the phyB-LG1-HB53 regulatory module as a key molecular mechanism governing plant architecture and density tolerance,providing potential genetic targets for breeding maize hybrid varieties suitable for high-density planting.
