Suffering from actuator failure and complex sideslip angle,the motion control of a sailboat becomes challenging.In this paper,an improved double finite-time observer-based line-of-sight guidance and finite-time contro...Suffering from actuator failure and complex sideslip angle,the motion control of a sailboat becomes challenging.In this paper,an improved double finite-time observer-based line-of-sight guidance and finite-time control(IDFLOS-FC)scheme is presented for path following of sailboats.The salient features of the proposed IDFLOS-FC scheme are as follows:(1)Considering the problem of actuator failure,an actuator failure model is introduced into the dynamics model of a sailboat.(2)The time-varying sideslip angle of the sailboat is accurately observed by the double finite-time sideslip observers(DFSOs),which reduces the error in line-of-sight(LOS)guidance.(3)A radial basis function(RBF)neural network is used to fit the uncertainty of the model,and the upper bound of the sum of fault effects and external disturbances is estimated based on adaptive theory,so that the controller has accurate tracking and interference suppression.(4)According to the Lyapunov method,the system is finite-time stable.Finally,simulation was used to validate the effectiveness of the method.展开更多
Rayleigh wave dispersion signals are significant to underground investigation.Tradition-ally,uniformed trace spacing is employed in surface wave surveys.In some cases,however,uneven trace spacing is often encountered ...Rayleigh wave dispersion signals are significant to underground investigation.Tradition-ally,uniformed trace spacing is employed in surface wave surveys.In some cases,however,uneven trace spacing is often encountered because of the limitations of the site condition.In order to study the influence of uneven trace spacing on the dispersion data construction of Rayleigh waves,data acquisi-tion is performed based on a 2.5D field layout with a linear array of geophones fixed and a mobile source.The observation direction controls the trace spacing of the measurement.The final results demonstrate that the trace nonuniformity has significant influence on the Rayleigh wave dispersion feature constructed.When the observation angle is over 45o,the dispersion image will be too distorted to extract dispersion data correctly.展开更多
Satellite multi-angle polarimetric(MAP)observations provide crucial insights into the microphysical and optical properties of atmospheric aerosols.Recent advancements in multi-angle,multispectral,and polarized satelli...Satellite multi-angle polarimetric(MAP)observations provide crucial insights into the microphysical and optical properties of atmospheric aerosols.Recent advancements in multi-angle,multispectral,and polarized satellite observations have increased data content and complexity.While traditional methods like look-up tables and optimal estimation face challenges in fully utilizing these advanced datasets,deep learning approaches offer substantial advantages.However,deep learning models also have limitations,particularly regarding physical interpretability and the efficiency of processing highdimensional observational data.To address these challenges,we propose MAP_CapsNet,a deep learning algorithm based on Capsule Networks(CapsNets)for aerosol multi-parameter retrieval.This algorithm combines the multi-dimensional modeling capabilities of CapsNets with vector radiative transfer models to retrieve aerosol optical and microphysical parameters.We applied it to MAP measurements from the Directional Polarimetric Camera(DPC)onboard the Gaofen-5(02)satellite to retrieve different aerosol parameters over China in 2022.The results were validated against Aerosol Robotic Network and Sun/sky-radiometer Observation Network data.The correlation coefficients(R)for aerosol optical depth and fine mode fraction exceed 0.935 and 0.782,respectively.The single scattering albedo also showed a moderate correlation(R=0.691).Compared with Moderate Resolution Imaging Spectroradiometer and Visible Infrared Imaging Radiometer Suite products,the DPC exhibited good spatial consistency and an enhanced ability to characterize aerosol properties due to higher spatial resolution and MAP capability.These findings highlight the DPC instrument’s potential for high-resolution,real-time monitoring of dust and haze pollution events.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52271306,52025111,and 51939003)the Central Guidance on Local Science and Technology Development Fund(No.2023JH6/100100010)the Fundamental Research Funds for the Central Universities(No.3132023501),China.
文摘Suffering from actuator failure and complex sideslip angle,the motion control of a sailboat becomes challenging.In this paper,an improved double finite-time observer-based line-of-sight guidance and finite-time control(IDFLOS-FC)scheme is presented for path following of sailboats.The salient features of the proposed IDFLOS-FC scheme are as follows:(1)Considering the problem of actuator failure,an actuator failure model is introduced into the dynamics model of a sailboat.(2)The time-varying sideslip angle of the sailboat is accurately observed by the double finite-time sideslip observers(DFSOs),which reduces the error in line-of-sight(LOS)guidance.(3)A radial basis function(RBF)neural network is used to fit the uncertainty of the model,and the upper bound of the sum of fault effects and external disturbances is estimated based on adaptive theory,so that the controller has accurate tracking and interference suppression.(4)According to the Lyapunov method,the system is finite-time stable.Finally,simulation was used to validate the effectiveness of the method.
基金supported by the "973-Project" (No. 2007CB714405)LIESMARS Special Research Funding,LOGEG Research Founding (No. 2008-02-08)the Key Laboratory of Precision Engineering & Industry Surveying,State Bureau of Surveying and Mapping
文摘Rayleigh wave dispersion signals are significant to underground investigation.Tradition-ally,uniformed trace spacing is employed in surface wave surveys.In some cases,however,uneven trace spacing is often encountered because of the limitations of the site condition.In order to study the influence of uneven trace spacing on the dispersion data construction of Rayleigh waves,data acquisi-tion is performed based on a 2.5D field layout with a linear array of geophones fixed and a mobile source.The observation direction controls the trace spacing of the measurement.The final results demonstrate that the trace nonuniformity has significant influence on the Rayleigh wave dispersion feature constructed.When the observation angle is over 45o,the dispersion image will be too distorted to extract dispersion data correctly.
基金supported by the National Outstanding Youth Foundation of China(Grant No.41925019)the National Key R&D Program of China(Grant No.2023YFB3907405)the National Natural Science Foundation of China(Grant No.42175148).
文摘Satellite multi-angle polarimetric(MAP)observations provide crucial insights into the microphysical and optical properties of atmospheric aerosols.Recent advancements in multi-angle,multispectral,and polarized satellite observations have increased data content and complexity.While traditional methods like look-up tables and optimal estimation face challenges in fully utilizing these advanced datasets,deep learning approaches offer substantial advantages.However,deep learning models also have limitations,particularly regarding physical interpretability and the efficiency of processing highdimensional observational data.To address these challenges,we propose MAP_CapsNet,a deep learning algorithm based on Capsule Networks(CapsNets)for aerosol multi-parameter retrieval.This algorithm combines the multi-dimensional modeling capabilities of CapsNets with vector radiative transfer models to retrieve aerosol optical and microphysical parameters.We applied it to MAP measurements from the Directional Polarimetric Camera(DPC)onboard the Gaofen-5(02)satellite to retrieve different aerosol parameters over China in 2022.The results were validated against Aerosol Robotic Network and Sun/sky-radiometer Observation Network data.The correlation coefficients(R)for aerosol optical depth and fine mode fraction exceed 0.935 and 0.782,respectively.The single scattering albedo also showed a moderate correlation(R=0.691).Compared with Moderate Resolution Imaging Spectroradiometer and Visible Infrared Imaging Radiometer Suite products,the DPC exhibited good spatial consistency and an enhanced ability to characterize aerosol properties due to higher spatial resolution and MAP capability.These findings highlight the DPC instrument’s potential for high-resolution,real-time monitoring of dust and haze pollution events.
