排序方式: 共有32条查询结果,搜索用时 15 毫秒
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Bong-Kyu Park Min-Jea Tahk Hyo-Choong Bang Chang-Su Park Jae-Hyun Jin 《Aerospace Science and Technology》2005,9(8):722
This paper proposes a new autonomous stationkeeping system suitable for geostationary satellite operation and presents the results of the computer simulations conducted to verify the proposed system. The proposed on-board stationkeeping system receives pseudo-range signal from the ground equipments located at two different positions with a long baseline, determines the orbit error in real-time, and generates the orbit control command. To minimize the complexity of the on-board stationkeeping logic and to improve reliability, a simple orbit controller has been designed, which generates a series of control signal making the orbit roughly follow the predetermined reference range data. The reference range data are assumed to be generated through a ground based computer simulation and embedded or uploaded with time tag. Finally, the performance of the proposed system has been verified through computer simulations. 相似文献
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具有独立失效模式的多自由度非线性振动系统的可靠性分析 总被引:11,自引:0,他引:11
对不考虑失效模式相关性的多自由度非线性随机振动系统可靠性进行了研究。在结构系统响应和状态函数的前四阶矩的一般数学表达式的基础上,使用 Edgeworth级数把未知响应和状态函数的概率分布展开成标准的正态分布表达式,并放松了对随机参数的分布概型和激励类型的限制,从而确定了系统的可靠度。 相似文献
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针对在轨磁悬浮飞轮转子系统,考虑发射主动段振动工况,提出一种基于灵敏度分析的多学科优化设计方法。通过比较分析内、外锁紧方案对锁紧状态飞轮转子系统共振频率的影响,得到了较优的抱式外锁紧方案。在此基础上,对飞轮转子进行灵敏度分析,并选择高灵敏度结构参数作为优化设计变量。考虑其结构强度、转动惯量、控制性能、自由状态和锁紧状态一阶共振频率,以飞轮转子质量最小为优化目标,利用序列二次规划法对其进行多学科优化设计。优化结果表明,在满足发射振动工况下,飞轮转子极转动惯量与质量的数值比达到最大为0.0070,比初始值0.0064提高了9.4%。该优化方法提高了飞轮转子设计的可靠性和效率,其首次在轨实验成功对我国磁悬浮飞轮空间应用具有重要意义。 相似文献
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杨涛%高殿斌%李开越%葛邦 《宇航材料工艺》2008,38(3):34-36
结合大梁带铺放工艺设计了预浸带铺放设备.铺放设备总体采用龙门式结构.分析了铺放设备运动规律和控制要求.采用西门子840D的Gantry功能对龙门架x向移动和横梁的y向移动实现双边同步驱动.针对大梁带铺放工艺要求采用840D的三轴联动和插补功能实现铺带头主运动,两个光栅传感器检测龙门位置(x,y座标),一个旋转编码器用于控制铺放头摆动位置(z座标).采用S7-300完成多数字I/O并行控制,搭建了铺带专用数控系统,很好的完成了铺带运动控制要求. 相似文献
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Baohua Lian Hyochoong Bang 《IEEE transactions on aerospace and electronic systems》2006,42(2):453-463
A nonlinear control law design based upon the backstepping approach is addressed for attitude maneuver control of spacecraft by momentum transfer (MT) in the presence of disturbance. For MT, a traditional method usually applies constant torque as an input, which tends to produce significant residual oscillation. Enhanced methods such as optimal control can somewhat reduce the residual oscillation, but may not be enough for minimum residual motion. Feedback linearization technique can drive the final nutation angle small enough, but it is rather sensitive to parameter uncertainty. The proposed method here takes advantage of nonlinear control approach with small steady-state nutation angle. Sensitivity about parameter uncertainties by feedback linearization can be reduced by the backstepping technique. Stability of the resulting control law is guaranteed by the Lyapunov stability theory. Boundedness of the control law is presented to validate practical merit of the proposed control law. 相似文献
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快速Gram-Schmidt回归方法 总被引:1,自引:1,他引:0
提出一种快速的变量筛选与回归建模方法.该方法将在建模过程中,一方面筛选出对因变量有最佳解释作用的信息;另一方面基于Gram-Schmidt正交变换,识别和检验模型中的冗余变量,以便能够及时和成批量地删除所有冗余信息.仿真分析指出,在自变量数量巨大,同时变量之间的多重相关程度又非常高的情形下,与经典的逐步回归相比,该方法的计算速度更快,建模过程更加简洁有效. 相似文献
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简述了核心机研制的目的和核心机试验的内容.并提出了核心机燃油与控制系统的选用原则和核心机控制计划的基本方法。可供核心机试验和核心机燃油与控制系统研究人员参考。 相似文献
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An adaptive control technique can be applicable to reorient spacecraft with uncertain properties such as mass, inertial and various misalignments. A nonlinear quaternion feedback controller is chosen as a baseline attitude controller. A linearly added adaptive input supported by neural networks to the baseline controller can estimate and eliminate the uncertain spacecraft property adaptively. The normalized input neural networks (NINNs) are examined for reliable computation of the adaptive input. The newly defined learning rules of the neural networks are established appropriately for a spacecraft. To prove the stability of the closed-loop dynamics with the control law, Lyapunov stability theory is considered. As a result, the proposed approach results in the uniform ultimate boundedness in tracking error and robustness of the chattering and the singularity problems. 相似文献
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