The active control theory and methods of initial disturbances for rockets and missiles are investigated. The rocket or missile/launcher is simplified as a flexible beam excited by a moving varying velocity rigid body ...The active control theory and methods of initial disturbances for rockets and missiles are investigated. The rocket or missile/launcher is simplified as a flexible beam excited by a moving varying velocity rigid body which has two points in contact with the beam. The control force is applied at the supporting point on the beam. Active control strategies based on optimal control theory are proposed and computer simulation is carried out. Simulation results are consistent with the theoretical results, and show that the active control strategies proposed can accomplish the purpose to control the initial disturbances actively. The results show that active control of initial disturbances for rockets and missiles is feasible for application.展开更多
Underwater vehicles are being emphasized as highly integrated and intelligent devices for a significant number of oceanic operations. However, their precise operation is usually hindered by disturbances from a tether ...Underwater vehicles are being emphasized as highly integrated and intelligent devices for a significant number of oceanic operations. However, their precise operation is usually hindered by disturbances from a tether or manipulator because their propellers are unable to realize a stable suspension. A dynamic multi-body model-based adaptive controller was designed to allow the controller of the vehicle to observe and compensate for disturbances from a tether or manipulator. Disturbances, including those from a tether or manipulator, are deduced for the observation of the controller. An analysis of a tether disturbance covers the conditions of the surface, the underwater area, and the vehicle end point. Interactions between the vehicle and manipulator are mainly composed of coupling forces and restoring moments.To verify the robustness of the controller, path-following experiments on a streamlined autonomous underwater vehicle experiencing various disturbances were conducted in Song Hua Lake in China. Furthermore,path-following experiments for a tethered open frame remote operated vehicle were verified for accurate cruising with a controller and an observer, and vehicle and manipulator coordinate motion control during the simulation and experiments verified the effectiveness of the controller and observer for underwater operation. This study provides instructions for the control of an underwater vehicle experiencing disturbances from a tether or manipulator.展开更多
In this paper, the disturbances to a uniformly rotating ideal fluid with a sphere moving steadily along the axis of rotation are analysed by using linearization theory, the equations of disturbance pressure and distur...In this paper, the disturbances to a uniformly rotating ideal fluid with a sphere moving steadily along the axis of rotation are analysed by using linearization theory, the equations of disturbance pressure and disturbance stream function governing the stability of motion are derived based on the assumption that the flow is rotational symmetric. The equation of disturbance stream function is analysed with the method of normal modes, and the constraints on wave number and wave velocity of the nontrivial neutral disturbances are established and the exact expression of the neutral disturbances are obtained. The conclusion is drawn that there are three kinds of possible forms of neutral disturbances.展开更多
目的综述头颈部肿瘤患者身体意象失调的现状、评估工具及影响因素。方法以Arksey和O'Malley提出的范围综述方法学为指导,检索Pubmed、Web of Science、Cochrance Library、Embase、Scopus、CINAHL、中国知网、万方、维普和中国生物...目的综述头颈部肿瘤患者身体意象失调的现状、评估工具及影响因素。方法以Arksey和O'Malley提出的范围综述方法学为指导,检索Pubmed、Web of Science、Cochrance Library、Embase、Scopus、CINAHL、中国知网、万方、维普和中国生物医学文献数据库中相关研究,检索时限为建库至2023年11月13日。结果共纳入20篇文献,整合分析结果显示,头颈部肿瘤患者身体意象失调发生率较高,评估工具以普适性量表为主,影响头颈部肿瘤患者身体意象失调的因素包括人口学因素、疾病及治疗相关因素、心理及应对能力因素、家庭社会环境因素4个方面。结论头颈部肿瘤患者身体意象失调较为常见且受诸多因素影响,医护人员未来应加强对头颈部肿瘤患者身体意象失调的重视度,根据我国文化背景开发合适的头颈部肿瘤患者身体意象失调特异性评估工具,并依据相关影响因素为头颈部肿瘤患者提供针对性的评估与照护,以减少头颈部肿瘤患者身体意象失调的发生与发展,改善其生存质量。展开更多
文摘The active control theory and methods of initial disturbances for rockets and missiles are investigated. The rocket or missile/launcher is simplified as a flexible beam excited by a moving varying velocity rigid body which has two points in contact with the beam. The control force is applied at the supporting point on the beam. Active control strategies based on optimal control theory are proposed and computer simulation is carried out. Simulation results are consistent with the theoretical results, and show that the active control strategies proposed can accomplish the purpose to control the initial disturbances actively. The results show that active control of initial disturbances for rockets and missiles is feasible for application.
基金Supported by National Natural Science Foundation of China(Grant Nos.5129050,51579053,61633009)Major National Science and Technology Project of China(Grant No.2015ZX01041101)Key Basic Research Project of "Shanghai Science and Technology Innovation Plan" of China (Grant No.15JC1403300)
文摘Underwater vehicles are being emphasized as highly integrated and intelligent devices for a significant number of oceanic operations. However, their precise operation is usually hindered by disturbances from a tether or manipulator because their propellers are unable to realize a stable suspension. A dynamic multi-body model-based adaptive controller was designed to allow the controller of the vehicle to observe and compensate for disturbances from a tether or manipulator. Disturbances, including those from a tether or manipulator, are deduced for the observation of the controller. An analysis of a tether disturbance covers the conditions of the surface, the underwater area, and the vehicle end point. Interactions between the vehicle and manipulator are mainly composed of coupling forces and restoring moments.To verify the robustness of the controller, path-following experiments on a streamlined autonomous underwater vehicle experiencing various disturbances were conducted in Song Hua Lake in China. Furthermore,path-following experiments for a tethered open frame remote operated vehicle were verified for accurate cruising with a controller and an observer, and vehicle and manipulator coordinate motion control during the simulation and experiments verified the effectiveness of the controller and observer for underwater operation. This study provides instructions for the control of an underwater vehicle experiencing disturbances from a tether or manipulator.
文摘In this paper, the disturbances to a uniformly rotating ideal fluid with a sphere moving steadily along the axis of rotation are analysed by using linearization theory, the equations of disturbance pressure and disturbance stream function governing the stability of motion are derived based on the assumption that the flow is rotational symmetric. The equation of disturbance stream function is analysed with the method of normal modes, and the constraints on wave number and wave velocity of the nontrivial neutral disturbances are established and the exact expression of the neutral disturbances are obtained. The conclusion is drawn that there are three kinds of possible forms of neutral disturbances.
文摘目的综述头颈部肿瘤患者身体意象失调的现状、评估工具及影响因素。方法以Arksey和O'Malley提出的范围综述方法学为指导,检索Pubmed、Web of Science、Cochrance Library、Embase、Scopus、CINAHL、中国知网、万方、维普和中国生物医学文献数据库中相关研究,检索时限为建库至2023年11月13日。结果共纳入20篇文献,整合分析结果显示,头颈部肿瘤患者身体意象失调发生率较高,评估工具以普适性量表为主,影响头颈部肿瘤患者身体意象失调的因素包括人口学因素、疾病及治疗相关因素、心理及应对能力因素、家庭社会环境因素4个方面。结论头颈部肿瘤患者身体意象失调较为常见且受诸多因素影响,医护人员未来应加强对头颈部肿瘤患者身体意象失调的重视度,根据我国文化背景开发合适的头颈部肿瘤患者身体意象失调特异性评估工具,并依据相关影响因素为头颈部肿瘤患者提供针对性的评估与照护,以减少头颈部肿瘤患者身体意象失调的发生与发展,改善其生存质量。
