姿态控制系统是卫星系统中重要的组成部分,由于其高昂的造价,发生故障会引发恶劣的影响。随着航天科技的发展,卫星姿态控制系统也逐渐复杂,其可能发生故障的概率也随之增大。针对传统神经网络故障诊断结果缺少置信度、鲁棒性较差以及易...姿态控制系统是卫星系统中重要的组成部分,由于其高昂的造价,发生故障会引发恶劣的影响。随着航天科技的发展,卫星姿态控制系统也逐渐复杂,其可能发生故障的概率也随之增大。针对传统神经网络故障诊断结果缺少置信度、鲁棒性较差以及易发生过拟合的缺点,在对贝叶斯统计和深度学习理论研究的基础上,提出了一种基于贝叶斯线性层与贝叶斯卷积层的Bayesian Le Net结合的网络模型。通过对卫星姿态控制系统飞轮部件的故障数据分析和处理,进而采用该模型对故障仿真,并与贝叶斯全连接神经网络与传统Le Net进行对比,实验结果表明:在飞轮可能发生的三种故障前提下,上述网络模型准确率较高,过拟合现象较轻。验证了上述网络模型的有效性。展开更多
A computational framework for parachute inflation is developed based on the immersed boundary/finite element approach within the open-source IBAMR library.The fluid motion is solved by Peskin's diffuse-interface i...A computational framework for parachute inflation is developed based on the immersed boundary/finite element approach within the open-source IBAMR library.The fluid motion is solved by Peskin's diffuse-interface immersed boundary(IB)method,which is attractive for simulating moving-boundary flows with large deformations.The adaptive mesh refinement technique is employed to reduce the computational cost while retain the desired resolution.The dynamic response of the parachute is solved with the finite element approach.The canopy and cables of the parachute system are modeled with the hyperelastic material.A tether force is introduced to impose rigidity constraints for the parachute system.The accuracy and reliability of the present framework is validated by simulating inflation of a constrained square plate.Application of the present framework on several canonical cases further demonstrates its versatility for simulation of parachute inflation.展开更多
空间站在轨组装和长期运营阶段涉及到多飞行器独立飞行、飞行器间交会对接、多飞行器组合体融合控制、多飞行器分离过程控制和飞行器返回再入等复杂飞行任务,完整、真实的飞行模拟是必需且至关重要的.基于时间同步、实时数据交换的分布...空间站在轨组装和长期运营阶段涉及到多飞行器独立飞行、飞行器间交会对接、多飞行器组合体融合控制、多飞行器分离过程控制和飞行器返回再入等复杂飞行任务,完整、真实的飞行模拟是必需且至关重要的.基于时间同步、实时数据交换的分布式一体化仿真架构,设计了一种多飞行器协同的通用半物理制导、导航与控制(guidance,navigation and control,GNC)系统飞行模拟平台,可很好地满足复杂系统的飞行模拟需要.平台由若干灵活、可扩展的通用模拟器构成,单个模拟器通过配置可以实现任一飞行器的功能,能够独立对指定飞行器的全任务过程进行仿真.平台通过靶场仪器组B时间码(inter-range instramentation group-B,IRIG-B)信号进行时间同步,利用1553B总线完成动力学仿真数据实时交换,并在多模拟器之间通过协调机制实现热并网后进行协同仿真.该模拟平台成功应用于空间站飞行控制演练.展开更多
文摘姿态控制系统是卫星系统中重要的组成部分,由于其高昂的造价,发生故障会引发恶劣的影响。随着航天科技的发展,卫星姿态控制系统也逐渐复杂,其可能发生故障的概率也随之增大。针对传统神经网络故障诊断结果缺少置信度、鲁棒性较差以及易发生过拟合的缺点,在对贝叶斯统计和深度学习理论研究的基础上,提出了一种基于贝叶斯线性层与贝叶斯卷积层的Bayesian Le Net结合的网络模型。通过对卫星姿态控制系统飞轮部件的故障数据分析和处理,进而采用该模型对故障仿真,并与贝叶斯全连接神经网络与传统Le Net进行对比,实验结果表明:在飞轮可能发生的三种故障前提下,上述网络模型准确率较高,过拟合现象较轻。验证了上述网络模型的有效性。
基金supported by the Open Project of Key Laboratory of Aerospace EDLA,CASC(No.EDL19092208)。
文摘A computational framework for parachute inflation is developed based on the immersed boundary/finite element approach within the open-source IBAMR library.The fluid motion is solved by Peskin's diffuse-interface immersed boundary(IB)method,which is attractive for simulating moving-boundary flows with large deformations.The adaptive mesh refinement technique is employed to reduce the computational cost while retain the desired resolution.The dynamic response of the parachute is solved with the finite element approach.The canopy and cables of the parachute system are modeled with the hyperelastic material.A tether force is introduced to impose rigidity constraints for the parachute system.The accuracy and reliability of the present framework is validated by simulating inflation of a constrained square plate.Application of the present framework on several canonical cases further demonstrates its versatility for simulation of parachute inflation.
文摘空间站在轨组装和长期运营阶段涉及到多飞行器独立飞行、飞行器间交会对接、多飞行器组合体融合控制、多飞行器分离过程控制和飞行器返回再入等复杂飞行任务,完整、真实的飞行模拟是必需且至关重要的.基于时间同步、实时数据交换的分布式一体化仿真架构,设计了一种多飞行器协同的通用半物理制导、导航与控制(guidance,navigation and control,GNC)系统飞行模拟平台,可很好地满足复杂系统的飞行模拟需要.平台由若干灵活、可扩展的通用模拟器构成,单个模拟器通过配置可以实现任一飞行器的功能,能够独立对指定飞行器的全任务过程进行仿真.平台通过靶场仪器组B时间码(inter-range instramentation group-B,IRIG-B)信号进行时间同步,利用1553B总线完成动力学仿真数据实时交换,并在多模拟器之间通过协调机制实现热并网后进行协同仿真.该模拟平台成功应用于空间站飞行控制演练.
