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Pseudospectral Model Predictive Control for Exo-atmospheric Guidance
Rahman, Tawfiqur,Zhou, Hao,Yang, Liang,Chen, Wanchun The Korean Society for Aeronautical and Space Scie 2015 International Journal of Aeronautical and Space Sc Vol.16 No.1
This paper suggests applying pseudospectral model predictive method for exo-atmospheric guidance. The method is a fusion of pseudospectral law and model predictive control, in which a two point boundary value problem is formulated using model predictive approach and solved by applying pseudospectral law. In this work, the method is applied to exo-atmospheric guidance with specific target requirement. The existing exo-atmospheric guidance methods suffice general requirements for guidance, but cannot ensure specific target constraints; whereas, the presented method is able to do so. The proposed guidance law is assessed through simulation of perturbed cases, and the tests suggest that the method is able to operate semi-autonomously under control and thrust vector perturbations.
Waypoints Following Guidance for Surface-to-Surface Missiles
Zhou, Hao,Khalil, Elsayed M.,Rahman, Tawfiqur,Chen, Wanchun The Korean Society for Aeronautical Space Sciences 2018 International Journal of Aeronautical and Space Sc Vol.19 No.1
The paper proposes waypoints following guidance law. In this method an optimal trajectory is first generated which is then represented through a set of waypoints that are distributed from the starting point up to the final target point using a polynomial. The guidance system then works by issuing guidance command needed to move from one waypoint to the next one. Here the method is applied for a surface-to-surface missile. The results show that the method is feasible for on-board application.
Pseudospectral Model Predictive Control for Exo-atmospheric Guidance
Tawfiqur Rahman,Hao Zhou,Liang Yang,Wanchun Chen 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.1
This paper suggests applying pseudospectral model predictive method for exo-atmospheric guidance. The method is a fusion of pseudospectral law and model predictive control, in which a two point boundary value problem is formulated using model predictive approach and solved by applying pseudospectral law. In this work, the method is applied to exo-atmospheric guidance with specific target requirement. The existing exo-atmospheric guidance methods suffice general requirements for guidance, but cannot ensure specific target constraints; whereas, the presented method is able to do so. The proposed guidance law is assessed through simulation of perturbed cases, and the tests suggest that the method is able to operate semi-autonomously under control and thrust vector perturbations.
Waypoints Following Guidance for Surface-to-Surface Missiles
Hao Zhou,Elsayed M. Khalil,Tawfiqur Rahman,Wanchun Chen 한국항공우주학회 2018 International Journal of Aeronautical and Space Sc Vol.19 No.1
The paper proposes waypoints following guidance law. In this method an optimal trajectory is first generated which is then represented through a set ofwaypoints that are distributed from the starting point up to the final target point using a polynomial. The guidance system then works by issuing guidance command needed to move from one waypoint to the next one. Here the method is applied for a surface-to-surface missile. The results show that the method is feasible for on-board application.
Chongchong Wang,Liang Yang,Jinglin Li,Hong Zhao,Wanchun Chen 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.4
This paper aims at proposing an entry guidance algorithm for high lift-to-drag ratio entry vehicle, which is based on linear pseudospectral model predictive control and differential flatness theory. The algorithm consists of two phases: descent phase and glide phase. First, the longitudinal plane of the entry process is differentially flat, and the nonlinear system in the longitudinal plane can be transformed into a linear system using the properties of the differential flat system. Then, considering quadratic performance index, the entry longitudinal plane guidance problem is transformed into a linear optimal control problem with terminal constraints. Collocation with Legendre–Gaussian points is used to translate them into a set of algebraic equations. And then, the guidance commands of longitudinal plane, which reduce terminal errors, can be derived in an analytical manner in the form of polynomials. Finally, the heading angle error corridor is used to control the lateral plane motion to obtain the final guidance commands. To evaluate the guidance performance and robustness of the proposed algorithm, nominal trajectory simulation and Monte Carlo simulation were carried out for different target positions. The results show that this method has high computational efficiency, high numerical accuracy, strong adaptability, and robustness, which is applicable for many entry scenarios.
Wan, Chun,Shen, Yong-Chun,Liu, Meng-Qi,Yang, Ting,Wang, Tao,Chen, Lei,Yi, Qun,Wen, Fu-Qiang Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.9
The diagnosis of malignant mesothelioma (MM) remains a clinical challenge and the fluorescence in situ hybridization (FISH) assay has been reported to be one promising tool. The present meta-analysis aimed to establish the overall diagnostic accuracy of FISH for diagnosing MM. After a systematic review of English language studies, the sensitivity, specificity and other measures of accuracy of FISH in the diagnosis of MM were pooled using random-effects models. Summary receiver operating characteristic curves were applied to summarize overall test performance. Nine studies met our inclusion criteria, the pooled sensitivity and specificity for FISH for diagnosing MM being 0.72 (95% CI 0.67-0.76) and 1.00 (95% CI 0.98-1.00), respectively. The positive likelihood ratio was 34.5 (95% CI 14.5-82.10), the negative likelihood ratio was 0.24 (95% CI 0.16-0.36), and the diagnostic odds ratio was 204.9 (95% CI 76.8-546.6), the area under the curve being 0.99. Our data suggest that the FISH assay is likely to be a useful diagnostic tool for confirming MM. However, considering the limited studies and patients included, further large scale studies are needed to confirm these findings.