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481.
482.
针对考虑视场(FOV)约束和落角约束的高超声速飞行器高精度打击问题,提出一种基于自适应动态规划(ADP)的新型制导控制一体化(IGC)策略。首先设计一种融合视场角与落角约束的视场角指令,在视场角精确跟踪的同时实现精确命中并满足两种约束,从而将约束问题转化为跟踪问题;然后,借助干扰观测技术估计制导控制一体化模型中不确定性并引入到性能指标设计中,又同时将视场角约束与落角约束考虑进去,设计基于自适应动态规划的制导控制一体化方法。利用ADP的强化学习思想求解出最优控制策略,既保证高超声速飞行器的精准打击,又满足视场角约束与落角约束,而且兼顾了对不确定性的鲁棒性。仿真结果验证了本文所提方法的有效性与优势。 相似文献
483.
Flight risk prediction is significant in improving the flight crew’s situational awareness because it allows them to adopt appropriate operation strategies to prevent risk expansion caused by abnormal conditions, especially aircraft icing conditions. The flight risk space representing the nonlinear mapping relations between risk degree and the three-dimensional commanded vector(commanded airspeed, commanded bank angle, and commanded vertical velocity) is developed to provide the crew with practi... 相似文献
484.
在传统Kalman滤波中,卡方检测方法简单地将量测划分为正常和异常两种,针对其不足之处,改进并提出了一种新的软卡方检测方法。新方法根据卡方检测结果构造连续变化的量测,利用权重系数,充分挖掘处于正常值与异常值之间的可疑量测新息,同时还将该方法推广成多维量测的多分量卡方检测形式,建立了全面完整的软卡方检测Kalman滤波量测更新方程。最后,通过惯导/卫导组合导航仿真,验证了软卡方检测Kalman滤波的优势:无需任何参数调整且具有比Sage-Husa自适应滤波更小的统计误差波动。 相似文献
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487.
《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2023,71(3):1784-1805
In this paper, an adaptive modified sliding mode control approach is developed for attitude tracking of a nano-satellite with three magnetorquers and one reaction wheel. A sliding variable is chosen based on finite-time convergence of the nano-satellite attitude tracking error and avoiding the singularity of the control signal. The control gain of the proposed method is developed adaptively to reduce the tracking error and improve the closed-loop control performance. The sliding variable and adaptive parameter are also employed in the reaching phase of the control law to decrease the chattering phenomenon. In addition, the finite-time convergence of attitude variables in the presence of actuator faults, inertia uncertainty, and external disturbances is proved using the extended Lyapunov theorem. The simulations are conducted to evaluate the performance of the proposed method according to different evaluation criteria. Monte Carlo simulations are also used to survey the reliability of the system in the presence of the mentioned condition. 相似文献
488.
《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2023,71(5):2509-2520
This work develops a tension control strategy for deploying an underactuated spin-stable tethered satellite formation in the hub-spoke configuration. First, the Lagrange equation is used to model the spin-deployment dynamics of the tethered satellite formation. The central spacecraft is modeled as a rigid body, and the tethered subsatellites are simplified as lumped masses. Second, a pure tension controller has been proposed to suppress the tether libration motion in the deployment without thrusting at the subsatellites. A nonlinear sliding mode control is introduced in the tension controller for the underactuated system to suppress the periodic gravitational perturbations caused by the spinning hub-spoke tethered satellite formation. The unknown upper bounds of the perturbations are estimated by adaptive control law. The bounded stability of the closed-loop tension controller has been proved by the Lyapunov theory. Finally, numerical simulations validate the effectiveness and robustness of the proposed controller, i.e., tethers are fully deployed stably to the desired hub-spoke configuration. 相似文献
489.
《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2023,71(6):2640-2655
A multi-satellite co-tracking method for a single non-cooperative target is proposed to extend the arc of observation as well as to improve the accuracy of tracking. Firstly, the motion of the target is considered to be affected by J2 perturbation, and the model of multi-satellite co-tracking a single space target is designed with only measured angles. Then, a multi-satellite co-tracking method for a single space target based on an adaptive distributed spherical simplex information-weighted consensus filter (ADSSICF) is proposed. The spherical simplex is used to reduce the computational cost of the information filter, and to improve the efficiency of tracking. The angle-only measurement equation is linearized by the statistical linear regression method, and linearization errors are compensated for by updating measurement noise. By designing an adaptive consensus algorithm, only a small number of iterations are needed to achieve network consensus, to improve the convergence speed of the consensus algorithm, and prove the stability of ADSSICF. Finally, a simulation of four low-orbit satellites tracking a single space target is established. The focus of this paper is on the real-time performance and tracking accuracy of the multi-satellite co-tracking a single space target with angle-only based on ADSSICF. The performance of ADSSICF is verified from three indicators: the consensus and convergence of algorithm, the accuracy of state estimation. 相似文献
490.