A mixed H2/H∞ performance criterion with common Lyapunov matrix is proposed for polynomial fuzzy systems.Sufficient conditions for the existence of mixed H2/H∞ state feedback fuzzy controller are derived based on the polynomial fuzzy Lyapunov function and Sum-of-Squares (SOS) decomposation technique.The optimal H2/H∞ controller design approach is given by solving a parameter minimization problem with SOS constraints.

Aiming at the problem of blind source separation in noisy environment,wavelet de-noising method is introduced into blind source separation model.Two separation methods,pre-denoising+blind source separation algorithm,and pre-denoising+blind source separation algorithm+post-denoising,are analyzed theoretically.Then,comparison is made to the separation results of the two methods through digital simulation.The simulation shows that:1) Compared with the method only using blind source separation algorithm,the separation method combining wavelet de-noising with blind source separation algorithm has much better separation effect; and 2) The separation effect of pre-denoising+blind source separation algorithm+post-denoising is generally better than that of pre-denoising+blind source separation algorithm.

Aiming at the threat of Synthetic Aperture Radar and Ground Moving Target Indication (SAR-GMTI) to the moving target,a method of intermissive sampling and retransmitted jamming based on micro-motion modulation is presented,and analysis is made to its jamming performance.With this method,cosine phase modulation is made to the azimuth jamming in slow time domain,and the range jamming is retransmitted through intermittent sampling repeater.The combination of them provides 2D reticular jamming to the SAR image.The model of SAR jamming is constructed and the image output of the jamming is given.The countering performance against GMTI is analyzed by using the tri-channel interference canceling technique.The simulation results show that:The jamming still can produce 2D dots jamming performance for multi-channel SAR-GMTI because only a little part of it is cancelled,but the amplitudes of 2D dots have enhanced and weakened areas.

Considering that the effect of the multi-range-false-target deception jamming discrimination becoming worse as the intensive degree of multi-range-false-target increases,we proposed a method based on radial velocity estimation of radar network to discriminate the false target.Firstly,benchmark radar was selected and measurements were classified into groups for preprocessing,and the target measurements of other radars were transformed into the coordinate system of the benchmark radar for measurements association,thus to eliminate the false measurements and clutter as well as decrease the amount of computation.Then,the radial velocity of target was estimated by using the position information after coordinate transformation,which was then tested with the benchmark radar radial velocity for discriminating the false targets.Simulation results verified that proposed method can achieve high correct discrimination rate,and track the true target stably.

To improve the robustness of target detection under complex scene is an important and difficult challenge in the field of computer vision.The traditional moving target detection is based on the single feature of the target.In this paper,a new background modeling algorithm is proposed for object detection based on both color feature and texture feature.Firstly,the traditional color-based Gaussian mixture model is improved and the computation cost is reduced.Then the improved Gaussian mixture model is fused with the LBP texture model by D-S evidence theory.The experimental results show that the fusion of two features can be complementary.The proposed algorithm can detect the moving targets more rapidly and accurately compared with the traditional algorithm.

The traditional sparse coding model has poor feature selection performance,and the negative coefficient in the sparse-coefficient vectors may cause high dimensions and information redundancy,which is harmful for the object recognition.To solve the problem,a sparse coding model based on the adaptive elastic net is proposed.The model firstly extracts the feature points by AGAST (Adaptive and Generic Corner Detection Based on the Accelerated Segment Test) detector in scale space,and describes them by FREAK algorithm.Then the sparse-coefficient vectors are calculated out by applying an adaptive elastic net regression model that can select strong correlation features.Finally,target recognition is realized by classifier.The result shows that feature detection algorithm is more robust to the changes of scale,viewpoint,brightness,and rotation,and the recognition performance of the model has great improvement under the restriction of adaptive elastic net model.

In order to meet the requirements of modern high-tech warfare,reaction-jet/aerodynamic compound control and guidance technology can be used in missile control system to increase the mobility and accuracy of missiles.Firstly,the mathematical model of the missile in pitch plane is formulated,and the control law of reaction-jet and aerodynamics is designed separately by using switching control system.Secondly,the index reaching law and fuzzy control method are introduced to improve the accuracy of aerodynamic control.Simultaneously,the uncertain parameters design is optimized to enhance the effectiveness of reaction-jet control.At last,the simulation results show that the proposed scheme is very effective.

In order to make full use of the spatial information contained in the hyperspectral image,an improved bilateral filtering is applied to the target detection,and a bilateral filtering algorithm based on spectral angle matching for sparse representation of hyperspectral target detection is proposed.By combining the spectral angle matching with the bilateral filtering,the similarity between the pixels of hyperspectral image is used as the weight of bilateral filtering.The noise in the band is suppressed and the target is highlighted.Then the target detection is carried out by sparse representation algorithm.Experimental results show that:Compared with the traditional sparse representation method and the sparse representation algorithm with normal bilateral filtering,the proposed method has better detection performance.It is proved that making full use of the spatial information of hyperspectral images can further improve the target detection results.

Considering the problems of nonlinearity,uncertainty,and coupling existed in system model of longitudinal control system of short-range loitering missile,Active Disturbance Rejection Controller (ADRC) is integrated to deal with them.The structure,principle,algorithm implementation and parameter setting rules of ADRC are presented here.As to the trembling phenomenon and control performance degradation when the linear interval width of Extended State Observer (ESO)is small,a method of improved nonlinear function is proposed for design of the longitudinal motion control system.The result of simulation experiments with Simulink platform show that:1) The improved method effectively solves the problem of trembling and enhances the controller performance;and 2) The control system based on improved ADRC has good control performance.Therefore,the rationality of the improved method and control system is verified.

To improve the contrast of the fused image and preserve the rich and effective information of the source image,an image fusion algorithm based on Finite Discrete Shearlet (FDST) domain is proposed,with consideration of the excellent characteristics of FDST.Firstly,the source image is decomposed by FDST,and a series of high and low frequency subband coefficients are obtained.Then,the low frequency coefficients are selected by using the improved pixel weighting together with the regional spatial frequency;and the fusion method by the regional average gradient contrast is adopted for the selection of high frequency coefficients.Then,the fused image is obtained with the fusion coefficients reconstructed by inverse transform of FDST.The contrast experiment results show that:1) The fusion result of the algorithm is clear,natural and has appropriate contrast for human subjective vision perception;and 2) The objective evaluation quality indexes are improved compared with other fusion algorithms.It is confirmed that our algorithm is superior to other fusion algorithms,which greatly enhances the quality of image fusion.

For tracking the ground target with unknown maneuvering under gust disturbance,a global stable control policy is proposed for quad-rotor UAV.The control system is divided into position and attitude subsystems.In position subsystem,to the problem of no relative velocity measurement between the target and UAV,a bounded-output sliding mode position controller with observer is designed,which command outputs are in the specified range.The corresponding quaternion attitude controller is designed by using nonlinear switch term to achieve fast convergence.Therefore,the global stability property of the whole position-attitude system is achieved.Finally,the gust is modeled and the simulations of maneuvering target tracking missions show satisfactory tracking performance even in the wind field.

In order to solve the problem of helicopter′s route planning under the environment with complex terrain and threats,an improved pigeon-inspired optimization is proposed,in which the threat heuristic mechanism is integrated. The new algorithm makes full use of the known threat information in combat zone and takes it as the feedback information for guiding the flight,which can enhance the directivity of an individual during searching. The searching space constructed by allowed lists of way points can compress the searching space and ensure feasibility of the planned route. The simulation results show that the proposed method can effectively obtain the optimum route for the helicopter,which has the capability of terrain avoidance and threat avoidance.

This paper mainly introduces the application of non-acoustic antisubmarine detection technology in trailing detection of submarine by aerial platform. The characteristics of submarine trailing are presented,including track trailing,bubble trailing,thermal trailing,biology trailing,and magnetic trailing.According to their different characteristics,such non-acoustic detection technologies as SAR,laser radar,infrared radiation temperature measurement technology,hyper-spectral imaging and low-frequency magnetic anomaly detection technology are introduced.Analysis is made to the advantages and disadvantages of these non-acoustic technologies for submarine detection,and their potential application on aerial platform.Finally,expectation is made to the future application of the non-acoustic technologies in aviation antisubmarine of trailing detection.

Considering that the large aperture primary mirror of space optical remote sensor should have light weight and high surface quality,we designed an ultra-lightweight silicon carbide mirror.Firstly,the lightweight structure of the mirror was defined.Then,based on integrated optimization method,ISight software was used for implementing such design processes as geometric modeling,finite element analysis and surface fitting,and automatic operation was realized.The structure parameters of the mirror were all optimization variables,and both the mass and the RMS surface figure error of the mirror were taken as objective functions.The multi-objective,global optimization was achieved by using Non-dominated Sorting Genetic Algorithm II (NSGA-II).Finally,the optimal design was modified considering cast constraints and a verification model was constructed to evaluate the optimal design.The mass of the optimal mirror is 11.4 kg and the surface density is 37 kg/m2.Under the load of gravity vertical to the optical axis,the RMS surface figure error is 1 nm,and the first natural frequency reaches 1100 Hz.The result demonstrates the availability of the proposed approach.

Analysis is made to the damage evolution of the key component of hypersonic aircraft wing and the influence of flight dynamics on the damage.Based on establishment of damage dynamic model of the key components of hypersonic aircraft wing and dynamic model of hypersonic aircraft,and the loading stress analysis of the key components of wing,the effects of flight altitude,air speed,angle of attack and deflection of control surfaces on the dynamic damage characteristics of the key components of wing are studied respectively,thus to confirm the key aircraft variables having significant influence on the damage.The results show that the angle of attack has the most significant influence on the damage evolution of the key components of wing.From the safety and life extending perspectives,the angle of attack should be kept within a strict range while the aircraft is flying at hypersonic speed.The results can provide a valuable reference for the design of structure reliability.

The design process of holographic waveguide display system is usually divided into grating design and waveguide design,which is unintuitive and incapable for machining error analysis.Therefore,we propose a new comprehensive method for holographic waveguide design,which analyzes the diffraction process and transmission process of light synthetically.Taking the 2-D exit-pupil expander holographic waveguide display system as an example,analysis is made to the error caused by the waveguide wedge and grating parameters.In addition,their influence on imaging quality is also analyzed.This analysis method can provide the required accuracy for manufacture process.

Being the core for attitude information measurement,the sensors onboard UAV can supply safe,reliable and comprehensive information,and their working status directly affects the safety of the plane. By means of fault diagnosis technology,we can realize early detection of faults,thus to avoid malignant accidents and enhance the operation safety and reliability of aircraft. In this paper,analysis is made to the working principle of the sensors onboard the UAV,and an analytical model of the execution mechanism of the UAV is established. Based on the model,the characteristics of the sensors are simulated. Then,a fault diagnosis algorithm,threshold-improved SPRT united ALG based on residual errors,is used for extracting the fault features from residual errors,thus to detect and determine the working status of sensors. Finally,a common mathematical model of actuator′s fault is established,and the fault characteristics of the sensor are simulated. The result shows that this scheme can effectively improve the accuracy of sensor fault diagnosis,and the fault diagnosis algorithm is effective.

Analysis was made to the tracking accuracy requirements of airborne laser weapon.Taking a typical laser communication motor model as the object of control,a high-accuracy controller was designed by using compound-axis tracking control technology and active disturbance rejection control theory,which can satisfy accuracy requirement of airborne laser weapon.Then,combined with engineering practice,the controller was simplified and improved by omitting the tracking-differentiator and changing the nonlinear control law and extended state observer into linear structure.Simulation results show that the designed controller can satisfy the angle tracking accuracy of coarse and fine tracking phases,and exhibits good flexibility and strong robustness against external disturbance and parameter uncertainty．

Based on the nonlinear flight control model of quadrotor aircraft, an improved method was proposed for self-tuning the coefficients of 2D direct-acting type fuzzy PID controllers. By analyzing the fuzzy logic relations between quantization factors and inputs/output of fuzzy logic controller, fuzzy logic tuners were designed separately for quantization factors, including the fuzzy inputs and fuzzy rules. A self-tuning algorithm was applied to implement on-line adjustment of the quantization factors. The simulation of attitude control of quadrotor aircraft was conducted by developing the dynamic model and analyzing the control channels. Comparing with the classical PID-type fuzzy logic controller, the proposed controller shows better performance on dynamic response speed and anti-interference capability.

Aiming at system architecture of the master-slave mode,dual redundancy flight control computer,a fault tolerant management strategy is proposed,and the algorithms are presented for system fault detection and diagnosis,system resource management,and fault recovery.The fault tolerant strategy algorithm is tested under the UAV semi-physical simulation platform.The results show that the strategy is correct,and the function and performance of the algorithm can meet the engineering application requirements.

When the temperature changes or is not uniform,the structural and optical elements of airborne photoelectrical equipment would deform,which may have effect on the optical system performance.In addition,too high or too low temperature may decrease the reliability and life of the critical elements.Therefore,it is very important to carry out thermal simulation and evaluation in design of the airborne photoelectrical equipment.The detector and PCBs are the main hot elements of the airborne photoelectrical equipment.So,how to improve the precision of thermal simulation becomes the key point to improve the validation of evaluation.In this paper,the composition,working principle,normal thermal modeling method of detector and PCB are presented,and an improved modeling method of the thermal simulation is given.Experimental verification results show that the precision of the proposed thermal simulation is improved remarkably,and thus the validation of evaluation is improved.

Analysis is made to the current development status of touch-screen control technology.According to the development demand and trend of display control in future civil aircraft cockpit,the usage scenario,intended function and technical requirements for touch-screen control are investigated,and compliance verification considerations are also proposed.

Study was made to structure parametric design of the airborne turret with a certain typical structure.The top-level characteristic parameters of components and parts of the turret were extracted,and the 3D parametric design models of them were established.Experimental results showed the effectiveness of the method.Database management of the parametric model was implemented by using the secondary development module of UG NX.Therefore,the models can be used as common resources.

Considering that it is difficult to collect vibration signal of the running gearbox bearings for condition monitoring and fault diagnosis,we used infrared thermal image to carry out the jobs.Firstly,infrared thermal images of the two end bearings of the gearbox were collected by infrared thermography,and the infrared thermal image was decomposed into intrinsic mode function through bi-dimensional empirical mode decomposition.Then,the image was processed for image fusion with the principal component analysis method,and the image with enhanced contrast was obtained.Finally,feature parameters of the original image and the enhanced image were extracted,and cluster analysis was used to isolate the bearings of different states.It is proved that the infrared thermal image can accurately diagnose the faults of bearings.