Xiaolin Feng

This paper presents an active fault-tolerant method to mitigate sensor failures in multimotor synchronous control. First, inspired by the construction of the coupling matrix in complex network synchronous output, a consistent matrix is designed based on structural redundancy in synchronous control. This consistent matrix has two advantages: one is that it can reflect different sensor output similarities and the other one is that it can detect, locate, and estimate the sensor fault. Then, the fault information is integrated into the design of tolerance control with an improved mean feedback mechanism. The proposed method is suitable for both single and multiple fault situations, and its effectiveness is finally verified by both MATLAB simulation and the ABB semiphysical experimental platform.

In view of the speed sensor faults in elevating stage control system, an active fault tolerant control approach based on a novel tracking differentiator is proposed in this paper. First, the analytical redundancy relationship between the velocity and displacement signals in a dual closed loop control system is used to detect a fault. When the deviation between the differential of normal displacement sensor signal and the fault speed sensor output exceeds a certain threshold value, a fault can be considered to occur. Secondly, after a fault is detected, the output of the fault sensor is replaced immediately with the differential signal of the output from a normal sensor to ensure the safety of the postfault system. In the process of signal differential, considering the drawbacks of the traditional method which uses inertial element to approximate differentiator and complex parameter tuning of Han’s Tracking Differentiator (TD), a novel tracking differentiator based on hyperbolic tangent function (Tanh-TD) is designed. Thirdly, in order to avoid the switching vibration and improve the reliability of FDD, a continuous smooth switching tactic based on exponential function is constructed. The simulation results show that the fault diagnosis method is simple and timely, the designed tracking differentiator is fast and effective, and the effect of the fault tolerant control based on smooth switching strategy is also satisfactory.

For the encoder fault in lift stage machinery control system, an active fault tolerant control method based on signal reconstruction was proposed in the paper. Firstly, multi-scale morphological method was adopted to decompose the encoder fault signals. Considering the DIF filter's capacity of underlining the fault characteristic, it was used as feature extraction for decomposed signals to achieve fault diagnosis of encoder. Secondly, as incremental encoder and absolute encoder were used to measure the speed and position of the lift stage respectively, redundant function was formed. So when the fault was diagnosed online, the redundancy mentioned above will be utilized by selecting proper numerical integrator and differentiator to substitute reconstructed signal for fault signal, thus an active fault tolerant strategy was implemented with switch strategy.

This paper mainly presents an infrared sensor based bearing-only tracking approach based on bionics with single station system. First, an infrared sensor array based on insect's compound eye principle is designed. Then, an adaptive platform scanning mode is given. This mode based on gaze extends the range of space searching. Moreover, a registration technology and a bearing-only association gate are presented. Finally, use JPDA-IMM algorithm to estimate the states of the targets. The application of the system design in an engineering application proves its effectiveness and practicability.

Due to the advanced and unique features of multi-homing and multi-streaming, Stream Control Transmission Protocol is suitable for data communications over satellite network, however, the satellite network are characterized by long-propagation delays, large-bandwidth product, and corruption losses. Thus, these protocols (TCP, UDP, SCTP) doesnpsilat work better over the satellite link. In this paper, we propose a new strategy including Load sharing strategy and a new congestion control mechanism which aim to improve the performance of SCTP over satellite links. The effective of the proposed strategy is discussed and confirmed through experimental evaluations. The proposed strategy is implemented on the NS2 (Network Simulator Version 2.26) with an SCTP module. Simulation results demonstrate that the performance of SCTP is significantly improved.