In this paper,an algorithm on measurement noise with adaptive strong tracking unscented Kalman filter(ASTUKF)is advanced to improve the precision of pose estimation and the stability for data computation.To suppress h...In this paper,an algorithm on measurement noise with adaptive strong tracking unscented Kalman filter(ASTUKF)is advanced to improve the precision of pose estimation and the stability for data computation.To suppress high-frequency noise,an infinite impulse response filter(IIRF)is introduced at the front end of ASTUKF to preprocess the original data.Then the covariance matrix of the error is corrected and the measurement noise is estimated in the process of filtering.After that,the data from the experiment were tested on the hardware experiment platform.The experimental results show that compared to the traditional extended Kalman filter(EKF)and unscented Kalman filter(UKF)algorithms,the root mean square error(RMSE)of the roll axis results from the algorithm proposed in this paper is respectively reduced by approximately 57.5%and 36.1%;the RMSE of the pitch axis results decreases by nearly 58.4%and 51.5%,respectively;and the RMSE of the yaw axis results decreases almost 62.8%and 50.9%,correspondingly.The above results indicate that the algorithm enhances the ability of resisting high-frequency vibration interference and improves the accuracy of attitude solution.展开更多
We report on the measurement of shear viscosity in an ultracold Fermi gas with variable temperatures and tunable interactions.A quadrupole mode excitation in an isotropic harmonic trap is used to quantify the shear vi...We report on the measurement of shear viscosity in an ultracold Fermi gas with variable temperatures and tunable interactions.A quadrupole mode excitation in an isotropic harmonic trap is used to quantify the shear viscosity of the quantum gas within the hydrodynamic regime.The shear viscosity of the system as a function of temperature has been investigated,and the results closely align with calculations in the high-temperature limit utilizing a new definition of the cutoff radius.Through an adiabatic sweep across the Bardeen–Cooper–Schrieffer(BCS)to Bose–Einstein condensate(BEC)crossover,we find that the minimum value of the shear viscosity,as a function of interaction strength,is significantly shifted toward the BEC side.Furthermore,the behavior of the shear viscosity is asymmetric on both sides of the location of the minimum.展开更多
基金supported by the Key Research and Development Program of Shaanxi Province(No.2024NC-YBXM-246)the Shaanxi Provincial Science and Technology Department(No.2024JC-YBQN-0725)+1 种基金the Education Department of Shaanxi Province(No.23JK0371)the Shaanxi University of Technology(No.SLGRCQD2318).
文摘In this paper,an algorithm on measurement noise with adaptive strong tracking unscented Kalman filter(ASTUKF)is advanced to improve the precision of pose estimation and the stability for data computation.To suppress high-frequency noise,an infinite impulse response filter(IIRF)is introduced at the front end of ASTUKF to preprocess the original data.Then the covariance matrix of the error is corrected and the measurement noise is estimated in the process of filtering.After that,the data from the experiment were tested on the hardware experiment platform.The experimental results show that compared to the traditional extended Kalman filter(EKF)and unscented Kalman filter(UKF)algorithms,the root mean square error(RMSE)of the roll axis results from the algorithm proposed in this paper is respectively reduced by approximately 57.5%and 36.1%;the RMSE of the pitch axis results decreases by nearly 58.4%and 51.5%,respectively;and the RMSE of the yaw axis results decreases almost 62.8%and 50.9%,correspondingly.The above results indicate that the algorithm enhances the ability of resisting high-frequency vibration interference and improves the accuracy of attitude solution.
基金supported by the National Key R&D Program(Grant No.2022YFA1404102)the National Natural Science Foundation of China(Grant Nos.U23A2073,12374250,and 12121004)+1 种基金Chinese Academy of Sciences(Grant No.YJKYYQ20170025)Hubei Province(Grant No.2021CFA027).
文摘We report on the measurement of shear viscosity in an ultracold Fermi gas with variable temperatures and tunable interactions.A quadrupole mode excitation in an isotropic harmonic trap is used to quantify the shear viscosity of the quantum gas within the hydrodynamic regime.The shear viscosity of the system as a function of temperature has been investigated,and the results closely align with calculations in the high-temperature limit utilizing a new definition of the cutoff radius.Through an adiabatic sweep across the Bardeen–Cooper–Schrieffer(BCS)to Bose–Einstein condensate(BEC)crossover,we find that the minimum value of the shear viscosity,as a function of interaction strength,is significantly shifted toward the BEC side.Furthermore,the behavior of the shear viscosity is asymmetric on both sides of the location of the minimum.
