According to the needs of dim and small target detection, a new detection algorithm based on wavelet transform and image fusion is put forward in the paper. In this algorithm, firstly, the original image is decomposed and reconstructed by wavelet and it is separated into a low frequency image and some high frequency images., secondly, the low frequency image is removed and the high frequency images are fused into a new image , finally, the fused image is segmented with threshold and the target is detected and signed. After the flight test validation, this algorithm has better accuracy and stability.
A new control problem of roll-pitch seeker about the disturbance coupling is investigated in this work. Previous control strategies of roll-pitch seeker rarely considered the effects of the dynamic coupling disturbances from the missile angular motion, and because of the polar coordinate structure, the disturbance rejection strategies of yaw-pitch seeker cannot be utilized directly on roll-pitch seeker. Thus this article presents a new control strategy to improve the disturbance rejection ability of roll-pitch seeker. To analyze the disturbance coupling problem, the roll-pitch seeker model is derived with consideration of the missile body angular motion and torque disturbances. The motion equation of roll-pitch seeker shows that part of the dynamic coupling disturbance can be eliminated by certain choices of inertial parameters. The rest of disturbance is reduced by the stabilization loops using a differentiator-based disturbance compensation controller. Particularly, a missile body angular acceleration estimation method is designed for the compensator based on an adaptive differentiator. In addition, comparisons with other control strategies are carried out via numerical simulations, and the results confirm the effectiveness of the proposed method.
The control of the speed of the diesel engine is the key to guarantee the AC output quality of the DGS (Diesel Generator Set). Because of the heavy noise and pollution of the physical DGS, it is a good way to build the mathematical model for research on the control of the diesel engine output speed. But the theoretical models often were not accurate and their control algorithms had poor usability due to nonlinearity and soft parameters of the diesel engine. To solve these problems, a Hardware-in-the-Loop (HIL) simulation system of the DGS has been built in this paper. In the HIL system, the power unit (includes diesel engine, generator and load tank) is replaced by the mathematic model, and the other devices are same as ones in the physical DGS. In order to ensure the accuracy of the model, this paper proposes modeling method for the power unit of the DGS. Thanks to the NARMAX (Nonlinear Auto-Regressive Moving Average with eXogenous inputs) model's good ability to describe the nonlinear system, the measurement data of the power unit are used to training NARMAX model and a high accuracy model of the power unit has been obtained. The experiments on the HIL system show the model can reproduce the static and dynamic characteristic of the physical DGS power unit to meet the research needs of the electronic governor.
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