蛙人超短基线(Ultra-Short Base Line, USBL)定位设备实现浅水环境下高精度定位的关键技术之一是精确的时延估计。由于自适应时延估计方法具备环境自适应能力强的特点,文章将混合调制的拉格朗日直接时延估计方法应用于蛙人USBL定位时的...蛙人超短基线(Ultra-Short Base Line, USBL)定位设备实现浅水环境下高精度定位的关键技术之一是精确的时延估计。由于自适应时延估计方法具备环境自适应能力强的特点,文章将混合调制的拉格朗日直接时延估计方法应用于蛙人USBL定位时的高精度测向上,它可以在信标信号中心频率已知的情况下将小数时延滤波器调制到信号中心频率处,以较低的阶数提供更高的时延估计精度;并根据USBL阵型和信号自身的特点,对混合调制的拉格朗日直接时延估计在低信噪比下的具体使用模式进行了探讨和仿真验证;结果显示,所采用的自适应时延估计方法可以在中低信噪比下提供1°~3°的定位测向精度。展开更多
The stochastic stability problem was considered for a class of gene regulatory networks with mixed time-delays.The mixed time-delays under consideration comprise both discrete timevarying delays and distributed time-d...The stochastic stability problem was considered for a class of gene regulatory networks with mixed time-delays.The mixed time-delays under consideration comprise both discrete timevarying delays and distributed time-delays.By employing a new Lyapunov function and conducting stochastic analysis,a linear matrix inequality(LMI) approach was developed to derive the criteria ensuring stability.The proposed criteria can be checked by using Matlab LMI toolbox.A simple example was provided to demonstrate the good effectiveness and applicability of the proposed testing criteria.展开更多
This paper deals with exponential synchronization for a class of neural networks with mixed time-varying delays via periodically intermittent control. Some novel and effective exponential synchronization criteria are ...This paper deals with exponential synchronization for a class of neural networks with mixed time-varying delays via periodically intermittent control. Some novel and effective exponential synchronization criteria are derived by constructing Lyapunov functional and applying some analysis techniques. These results presented in this paper generalize and improve many known results. Finally, this paper presents an illustrative example and uses the simulated results to show the feasibility and effectiveness of the proposed scheme.展开更多
In this paper, inertia is added to a simplified neuron system with time delay. The stability of the trivial equilibrium of the net- work is analyzed and the condition for the existence of Hopf bifurcation is obtained ...In this paper, inertia is added to a simplified neuron system with time delay. The stability of the trivial equilibrium of the net- work is analyzed and the condition for the existence of Hopf bifurcation is obtained by discussing the associated characteristic equation. Hopf bifurcation is investigated by using the perturbation scheme without the norm form theory and the center man- ifold theorem. Numerical simulations are performed to validate the theoretical results and chaotic behaviors are observed. Phase plots, time history plots, power spectra, and Poincar6 section are presented to confirm the chaoticity. To the best of our knowledge, the chaotic behavior in this paper is new to the previously published works.展开更多
A distributed fault-tolerant strategy for the controller area network based electric swing system of hybrid excavators is proposed to achieve good performance under communication errors based on the adaptive compensat...A distributed fault-tolerant strategy for the controller area network based electric swing system of hybrid excavators is proposed to achieve good performance under communication errors based on the adaptive compensation of the delays and packet dropouts. The adverse impacts of communication errors are effectively reduced by a novel delay compensation scheme, where the feedback signal and the control command are compensated in each control period in the central controller and the swing motor driver, respectively, without requiring additional network bandwidth. The recursive least-squares algorithm with forgetting factor algorithm is employed to identify the time-varying model parameters due to pose variation, and a reverse correction law is embedded into the feedback compensation in consecutive packet dropout scenarios to overcome the impacts of the model error. Simulations and practical experiments are conducted. The results show that the proposed fault-tolerant strategy can effectively reduce the communication-error-induced overshoot and response time variation.展开更多
文摘蛙人超短基线(Ultra-Short Base Line, USBL)定位设备实现浅水环境下高精度定位的关键技术之一是精确的时延估计。由于自适应时延估计方法具备环境自适应能力强的特点,文章将混合调制的拉格朗日直接时延估计方法应用于蛙人USBL定位时的高精度测向上,它可以在信标信号中心频率已知的情况下将小数时延滤波器调制到信号中心频率处,以较低的阶数提供更高的时延估计精度;并根据USBL阵型和信号自身的特点,对混合调制的拉格朗日直接时延估计在低信噪比下的具体使用模式进行了探讨和仿真验证;结果显示,所采用的自适应时延估计方法可以在中低信噪比下提供1°~3°的定位测向精度。
基金the Science Fund of the State Key Laboratory of Automotive Safety and Energy,Tsinghua Universityand the Chinese National Program for High Technology Research and Development
基金National Natural Science Foundation of China (No. 60874113)Key Creative Project of Shanghai Education Community,China (No. 09ZZ66)+1 种基金the Research Fund for the Doctoral Program of Higher Education,China (No. 200802550007)Key Basic Research Project of Shanghai,China (No. 09JC1400700)
文摘The stochastic stability problem was considered for a class of gene regulatory networks with mixed time-delays.The mixed time-delays under consideration comprise both discrete timevarying delays and distributed time-delays.By employing a new Lyapunov function and conducting stochastic analysis,a linear matrix inequality(LMI) approach was developed to derive the criteria ensuring stability.The proposed criteria can be checked by using Matlab LMI toolbox.A simple example was provided to demonstrate the good effectiveness and applicability of the proposed testing criteria.
基金This work was supported by the National Natural Science Foundation of China （No. 61305076）.
文摘This paper deals with exponential synchronization for a class of neural networks with mixed time-varying delays via periodically intermittent control. Some novel and effective exponential synchronization criteria are derived by constructing Lyapunov functional and applying some analysis techniques. These results presented in this paper generalize and improve many known results. Finally, this paper presents an illustrative example and uses the simulated results to show the feasibility and effectiveness of the proposed scheme.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11202068 and 11032009)
文摘In this paper, inertia is added to a simplified neuron system with time delay. The stability of the trivial equilibrium of the net- work is analyzed and the condition for the existence of Hopf bifurcation is obtained by discussing the associated characteristic equation. Hopf bifurcation is investigated by using the perturbation scheme without the norm form theory and the center man- ifold theorem. Numerical simulations are performed to validate the theoretical results and chaotic behaviors are observed. Phase plots, time history plots, power spectra, and Poincar6 section are presented to confirm the chaoticity. To the best of our knowledge, the chaotic behavior in this paper is new to the previously published works.
基金the National Natural Science Foundation of China （Nos. 51475414, 51475422, and 51521064） and the National Basic Research Program （973） of China （No. 2013CB035405）
文摘A distributed fault-tolerant strategy for the controller area network based electric swing system of hybrid excavators is proposed to achieve good performance under communication errors based on the adaptive compensation of the delays and packet dropouts. The adverse impacts of communication errors are effectively reduced by a novel delay compensation scheme, where the feedback signal and the control command are compensated in each control period in the central controller and the swing motor driver, respectively, without requiring additional network bandwidth. The recursive least-squares algorithm with forgetting factor algorithm is employed to identify the time-varying model parameters due to pose variation, and a reverse correction law is embedded into the feedback compensation in consecutive packet dropout scenarios to overcome the impacts of the model error. Simulations and practical experiments are conducted. The results show that the proposed fault-tolerant strategy can effectively reduce the communication-error-induced overshoot and response time variation.
