In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LST...In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LSTM) neural network is nested into the extended Kalman filter(EKF) to modify the Kalman gain such that the filtering performance is improved in the presence of large model uncertainties. To avoid the unstable network output caused by the abrupt changes of system states,an adaptive correction factor is introduced to correct the network output online. In the process of training the network, a multi-gradient descent learning mode is proposed to better fit the internal state of the system, and a rolling training is used to implement an online prediction logic. Based on the Lyapunov second method, we discuss the stability of the system, the result shows that when the training error of neural network is sufficiently small, the system is asymptotically stable. With its application to the estimation of time-varying parameters of a missile dual control system, the LSTM-EKF shows better filtering performance than the EKF and adaptive EKF(AEKF) when there exist large uncertainties in the system model.展开更多
角点特征在机器人同步定位与建图(Simultaneous Localization and Mapping,SLAM)系统中具有关键性的作用。然而,由于环境差异、机器人运动距离和传感器的影响,导致现有测量方法的角点估计误差较大。本文在原有使用扩展卡尔曼滤波(Extend...角点特征在机器人同步定位与建图(Simultaneous Localization and Mapping,SLAM)系统中具有关键性的作用。然而,由于环境差异、机器人运动距离和传感器的影响,导致现有测量方法的角点估计误差较大。本文在原有使用扩展卡尔曼滤波(Extended Kalman Filter,EKF)融合激光和视觉SLAM数据的基础上,引入多新息理论,提出了多新息改进EKF融合激光和视觉SLAM数据算法。由于多新息理论能有效利用历史时刻的数据,使系统在原先只使用当前时刻数据的情况下,扩展为能够利用之前多个时刻的有效数据。因此,利用多新息理论改进EKF,可以充分利用之前时刻由角特征和垂线特征融合成的角点结果,从而提升角点估计精度和建图结果。实验结果表明,在室内坏境中,本文方法在迭代次数20次和100次时平均误差分别为0.0268和0.0109,相较于未改进EKF方法,角点估计的精度平均提升了33.9%。展开更多
文摘In this paper, a filtering method is presented to estimate time-varying parameters of a missile dual control system with tail fins and reaction jets as control variables. In this method, the long-short-term memory(LSTM) neural network is nested into the extended Kalman filter(EKF) to modify the Kalman gain such that the filtering performance is improved in the presence of large model uncertainties. To avoid the unstable network output caused by the abrupt changes of system states,an adaptive correction factor is introduced to correct the network output online. In the process of training the network, a multi-gradient descent learning mode is proposed to better fit the internal state of the system, and a rolling training is used to implement an online prediction logic. Based on the Lyapunov second method, we discuss the stability of the system, the result shows that when the training error of neural network is sufficiently small, the system is asymptotically stable. With its application to the estimation of time-varying parameters of a missile dual control system, the LSTM-EKF shows better filtering performance than the EKF and adaptive EKF(AEKF) when there exist large uncertainties in the system model.
