Table of Content

30 June 2020, Volume 41 Issue 6

Previous Issue    Next Issue

Contents

Contents

2020, 41(6):  0. 

Asbtract ( )   PDF (874KB) ( )  

Related Articles | Metrics

Paper

High-resolution Staring Imaging of Missile-borne Phased Array Detector Based on Wavefront Coding

CHENG Cheng， GAO Min， ZHOU Xiaodong， JI Yongxiang， ZONG Zhulin

2020, 41(6):  1041-1055.  doi:10.3969/j.issn.1000-1093.2020.06.001

Asbtract ( )   PDF (8209KB) ( )  

References | Related Articles | Metrics

The imaging algorithm of the missile-borne phased detector is studied to realize the forward-looking high-resolution imaging of new precision guided munitions. A high-resolution staring imaging algorithm based on wavefront coding is proposed，in which the adaptive monopulse response curve (MRC) is used to realize forward-looking high-resolution detection. The wavefront coding is used to detect the non-planar wavefront of beam，so as to increase the effective information of the strong scattering points in the target area carried by the instantaneous echo signal. Adaptive MRC is used to provide the capability of high-resolution azimuth angle measurement for missile，and MRC is directly optimized by using echo signal to focus the angle measurement section. The factors (such as SNR and random modulation range) affecting imaging accuracy are studied. The simulation experimental and field test results show that the maximun imaging error of non-planar wavefront is 2.4 m，the error of azimuth and distance is less than 2.5 m when using the actual echo signal，which can meet the actual needs of the missile. Key

Influence of Fluid Bulk Modulus on the Target Range Pressure Building-up Time of Hydro-mechanical Transmission in Full Power Shift

BAO Yong, ZHONG Zaimin, YANG Shujun, ZHANG Lu

2020, 41(6):  1056-1066.  doi:10.3969/j.issn.1000-1093.2020.06.002

Asbtract ( )   PDF (5057KB) ( )  

References | Related Articles | Metrics

In order to shorten the power shift time of hydro-mechanical transmission (HMT), the influence of bulk modulus for the oil containing gas on pressure building-up time of target range is explored based on the full power shift method. The oil tangent bulk modulus is theoretically analyzed and experimentally studied, and the change law of tangent bulk modulus of oil is obtained. A two-range arithmetic HMT is taken as the research object. The target range pressure building-up model in the power transition stage is established based on the full power shift method. The pressure building-up time of target range under the conditions of secant bulk modulus, tangent bulk modulus and pure oil bulk modulus was obtained by means of simulation analysis and protogype experiment. The results show that, when studying the pressure building-up time of target range in full power shift, the influence of oil gas content on the pressure building-up time must be considered, and the tangent bulk modulus should be used. The larger the oil gas content is, the smaller the tangent bulk modulus is, and the longer the pressure building-up time of target range is. Key

Influence of Circumferential Position Error of Planet Wheel Mounting Hole on Vibration Characteristics of Planetary Gear Train

WANG Xinlei， XIANG Changle， LI Chunming， PING Sitao

2020, 41(6):  1067-1076.  doi:10.3969/j.issn.1000-1093.2020.06.003

Asbtract ( )   PDF (6139KB) ( )  

References | Related Articles | Metrics

The circumferential position error of planet wheel mounting hole is a common error in the manufacturing process of planetary gear train, which may directly change the gear contact length and meshing phase of the meshing tooth pair in planetary gear train. The abnormal vibration and noise are induced by the hole circumferential positon error as well as the poor load sharing between planet gears, which accelerate the failure of planetary gear teeth. A new planetary gear train dynamic model considering hole circumferential positon error is proposed for the unclear exciting mechanisms of hole circumferential position error. In the proposed model, the relationships among contact line location, pressure angle, location angle and hole circumferential position error are studied, the contact line length fluctuation and meshing phase are discussed, and finally the dynamic responses of planetary gear train in the present of hole circumferential position error are obtained. The simulated results show that the hole circumferential position error directly leads to the phase and amplitude change of gear meshing stiffness; the load sharing characteristics,vibration displacement and dynamic transmission error of planetary gear train become worse, and an obvious modulation phenomenon has been found in the the vibration displacement. Finally, a carrier frame hole circumferential position error experiment is conducted to validate the correctness and effectiveness of the proposed method. Key

Accurate Landing Point Prediction of Warhead Airdrop Test

HAN Jinyang, BAI Chunhua, TAN Panlong

2020, 41(6):  1077-1084.  doi:10.3969/j.issn.1000-1093.2020.06.004

Asbtract ( )   PDF (2779KB) ( )  

References | Related Articles | Metrics

For the problem that the landing point of the parachute-warhead is affected by the initial state and external environment when the parachute-warhead is dropped by a tethered hot-air balloon, a prediction method of landing point is studied, a 6-DOF dynamic model of parachute-warhead system is established, and the landing process of warhead is analyzed based on the dynamic model, the initial swing angle of warhead, the wind field in the test area and the initial altitude of the warhead. The accurate prediction result of landing point parachute-warhead is obtained. The proposed method can be used to adjust the dropping position to make sure that the landing point of warhead is in the working area of testing instruments, and improve the efficiency and safety of damage test. The airdrop test results show that the proposed method can accurately predict the landing point and can be utilized to guide the actual warhead damage test. Key

Calculation of Trajectory of High-speed Spinning Projectile Based on Computational Fluid Dynamics/Rigid Body Dynamics Coupling

ZHONG Yang， WANG Liangming， WU Yingfeng

2020, 41(6):  1085-1095.  doi:10.3969/j.issn.1000-1093.2020.06.005

Asbtract ( )   PDF (5991KB) ( )  

References | Related Articles | Metrics

To study the real flight trajectory of high-speed spinning projectile, a computational fluid dynamics/rigid body dynamics (CFD/RBD) couping computational methodology is developed using improved simple low-dissipation advection upstream splitting method (SLAU2), dual time-stepping method and Spalart-Allmaras (S-A) turbulence model based on the ideas of adding the motion of projectile axis to the surfaces of control volumes and adding the spin motion to the wall boundary. A flow model with ALE form is established. An arbitrary Lagrangian-Eulerian (ALE) flow model is established. A coupled mathematical model of the projectile motion and the surfaces of control volume motion is developed, and the simultaneous calculation of flow equations and trajectory equations based on 4th order Runge-Kutta method is achieved. The research results show that the aerodynamic coupling method and time step have great influence on the trajectory coupling calculation results. The trajectory of M549 spinning projectile at 0.5 ms timesteps was simulated using the tighting coupling method. The simulated results are basically consistent with the results calculated by the aerodynamic model. The trajectory simulation result of a spin stabilized two-dimensional trajectory correction projectile shows that the characteristic of that rising moment causes the projectile nose drop, which is consistent with the result in Ref. \[29\]. Key

Research on Time-cooperative Guidance of Multiple Flight Vehicles with Time-varying Velocity

LI Wen， SHANG Teng， YAO Yinwei， ZHAO Qilun

2020, 41(6):  1096-1110.  doi:10.3969/j.issn.1000-1093.2020.06.006

Asbtract ( )   PDF (4093KB) ( )  

References | Related Articles | Metrics

A distributed time-cooperative three-dimensional guidance method based on nonlinear extended state observer is proposed for the simultaneous attack of powerless flight vehicles with time-varying velocity. The complex leading angle of flight vehicle is defined to deduce the simplified relative motion equation，and the relative distances between flight vehicle and target and the approaching velocity are selected as the coordination variables. Considering the time-varying velocity of flight vehicle in practical situation, the modeling error of velocity change rate and the external interference are taken as the disturbance, which make up for the shortcomings of the existing methods that restrict the velocity strictly to a constant velocity. The nonlinear extended state observer is designed to estimate system disturbances, and the consensus control protocol with disturbance estimation is demonstrated to guarantee the bounded consensus of all flight vehicles' attack times. For an angle between the velocity direction and the line of sight direction always existing in the time-cooperative guidance law based on the control protocol, the time-cooperative guidance law is switched to the finite-time convergent guidance law to ensure the final guidance accuracy and attack effect when simultaneous attack is basically realized, and the fuzzy logic rules are used to achieve the smooth connection of the two guidance laws. The effectiveness and advantages of the proposed distributed time-cooperative guidance method are verified by using the simulated results. Key

Jet from Exhaust Tunnel Outlet on Rocket Launch Site

QUAN Hui, XIE Jian, LI Liang, ZHANG Li

2020, 41(6):  1111-1122.  doi:10.3969/j.issn.1000-1093.2020.06.007

Asbtract ( )   PDF (5635KB) ( )  

References | Related Articles | Metrics

A method for analyzing the subsonic winding jet in the non-uniform wind field based on the theoretical formula of subsonic linear jet is proposed to research the change law of jet from the exhaust tunnel outlet on the launch site. The axis equation of the winding jet under the non-uniform wind field, and the approximate formulas of jet half-width, velocities on cross sections, flow mass and velocities on axis are derived, and the velocities of incompressible winding jet under the conditions of constant wind speed, different initial half-widths and different speed ratios are calculated by using approximate formulas and computational fluid dynamics(CFD) method. The parameters of the approximate formulas are adjusted based on CFD results, and the influences of different initial half-widths and speed ratios on jet are analyzed. The results show that the approximate formulas can be used to calculate jet accurately, the change in initial half-width has little influence on jet, and the change in speed ratio has more influence on jet. The proposed method is feasible for analyzing the jet from exhanst tunnel outlet on rocket launch site.Key

Mechanism and Experimental Study of High Volatile Liquid Mass Transfer Rate

LIU Wenjie, BAI Chunhua, LIU Qingming, YAO Jian, WANG Ye

2020, 41(6):  1123-1130.  doi:10.3969/j.issn.1000-1093.2020.06.008

Asbtract ( )   PDF (6146KB) ( )  

References | Related Articles | Metrics

In order to study the calculation method of high volatile liquid mass transfer rate, a rectangular air duct is established, the different wind speed air flows are formed in the air passage, and the gas-liquid mass transfer loss on ether with 103.9 mm liquid surface diameter is studied experimentally, and the influences of different temperatures on the gas fluid transfer rate are analyzed. Based on the experimental results, the dimensional analysis below the boiling point temperature proposed by Donald Mackay^［12］ is carried out by using Maxwell's rate distribution theory and the gas-liquid mass transfer rate calculation model, and a new temperature correction term is proposed to correct the calculation model. The experimental results of liquid level show that the gas-liquid mass transfer rate decreases with the decrease in temperature and wind speed. The value of temperature correction term coefficient is 0.559 in comparison with the calculated value. The gas-liquid mass transfer rate is proportional to the powers of 0.78 of temperature and wind speed. A gas-liquid-liquid mass transfer heat transfer experiment was carried out to make the different diameter ether liquid columns pass through a 2.0 m/s air flow, and the measurement experiment was carried out. The temperature changes of liquid before and after experiment were measured. According to the modified gas-liquid mass transfer rate calculation model, the temperature change caused by gas-liquid mass transfer energy transfer during the liquid column down-flow process is calculated and compared with the experimental results. The experimental results of liquid column downflow show that the error between the calculated and experimental results is less than or equal to 3.81%, and the calculated error of the modified gas-liquid mass transfer rate calculation model is small with high computational accuracy. Key

Regional Coverage Cooperative Control Algorithm for Ad Hoc Networks

LIU Dakun， CHEN Guifen， WANG Yijun

2020, 41(6):  1131-1139.  doi:10.3969/j.issn.1000-1093.2020.06.009

Asbtract ( )   PDF (2505KB) ( )  

References | Related Articles | Metrics

Ad hoc networks regional coverage control algorithm has some problems including low covering efficiency， high energy consumption and poor transmission reliability. A cellular-genetic regional coverage cooperative control algorithm based on triangle subdivision (CRCCTS) is proposed on the basis of analyzing the network models of ad hoc networks. The CRCCTS algorithm takes the vertex structure of outer polygon of node coverage area as the datum， and divides the network coverage area into several subdomains through triangulation. Based on the dyeing scheme， the nodes at the subdomain vertices are defined as frequency nodes， and the cluster range is determined according to the different signal spectra after region division. Finally， the cellular genetic idea is used to solve the power control mode of self-organizing cooperative network nodes in the consideration of communication energy consumption and idle energy consumption. Simulated results show that, when the number of nodes is large （100-500 nodes），the coverage efficiency of CRCCTS algorithm can reach up to 3%，the energy consumption is reduced by at least 2 J, and the average end-to-end reliability is increased by at least 9.5% compared to balanced rate area coverage algorithm, discriminant construction algorithm for minimum node strong barrier, coverage configuration protocol algorithm, and multi-hop Ad Hoc wireless network energy-saving technology algorithm. Key

Conflict Evidence Combination Method Based on Interval Distance

WU Bin, YI Xiao, LI Shuangming

2020, 41(6):  1140-1150.  doi:10.3969/j.issn.1000-1093.2020.06.010

Asbtract ( )   PDF (1646KB) ( )  

References | Related Articles | Metrics

A conflict evidence combination method based on uncertain interval distance is proposed for the anti-intuitive problem about combination results of multiple pieces of evidences containing conflict evidence. Through the analysics in Refs. ［13, 15, 17］, it is found that the interval composed of Bel and Pl function contains all the information of an event, which solves the problem of information missing in the process of evidence combination directly composed of Mass function. The expression of uncertain interval is given, and then an interval distance is defined according to the uncertain interval. The interval distances among the same focal elements of different evidences are calculated, and the interval distances of all focal elements are summed. A distance matrix and weights among evidences are generated through the distance matrix, and the original evidences are corrected according to the weights. The evidence combination is completed with Dempster-Shafer(D-S) and Proportional Conflict Redistribution 6 (PCR 6). The example analysis shows that the proposed method agrees with the methods in Ref. ［33］ in the representation change of conflict degree, which shows the effectiveness of the proposed method. In the combination of multiple conflict evidences, the Bel of the proposed method is significantly improved compared with the existing methods. Key

PAPR Reduction Algorithm Based on PTS and CS in OFDM

CAO Yuan， CUI Donghua， LIU Xinghui

2020, 41(6):  1151-1156.  doi:10.3969/j.issn.1000-1093.2020.06.011

Asbtract ( )   PDF (1944KB) ( )  

References | Related Articles | Metrics

The orthogonal frequency division multiplexing (OFDM) is widely used in wireless system and becoming a key technology for weapon cooperation data link. A hybrid peak average power ratio (PAPR) reduction algorithm is proposed. It is based on modified partial transmission sequence (PTS) and compressed sensing (CS) in OFDM for further reducing PAPR and improving bit error rate performance. The framework and implementation steps of the algorithm are also proposed, which includes PAPR reduction at transmitter and CS recovery at receiver. Simulated results show that the algorithm combines the advantages of CS and PTS, reducing the peak-average power ratio by at least 1dB, and achieving better PAPR performance. Key

Damage Effect of Strong Electromagnetic Pulse on Micro-silicon Inertial Sensor

SHEN Jie， PAN Xuchao， FANG Zhong， HE Yong， CHEN Hong， ZHANG Jiangnan， SHI Yunlei

2020, 41(6):  1157-1164.  doi:10.3969/j.issn.1000-1093.2020.06.012

Asbtract ( )   PDF (7081KB) ( )  

References | Related Articles | Metrics

In order to study the damage effect of strong electromagnetic pulse on the micro-silicon inertial sensor of exoskeleton robotic system, the electromagnetic damage threshold, vulnerable devices and damage modes of micro-silicon inertial sensor are studied through theoretical calculation and experimental analysis. The strong electric pulse coupled and transmitted to the signal transmission ports by cables which are directly connected to sensor in electromagnetic pulse environment is calculated by using Agrawal transmission line theory and Green's function. And the strong electric pulse injection experiment of signal transmission ports and the damage mode analysis of sensor are carried out. The result shows that the damage threshold of micro-silicon inertial sensor is 780 V, the electromagnetic vulnerable components are front-end capacitor and signal amplifiers, and the main damage modes are high voltage breakdown of capacitor and high current burnout of amplifiers. Key

Detection and Identification of Ship Shaft-rate Electric Field Based on Line-spectrum Characteristics

ZHAO Wenchun， JIANG Runxiang， YU Peng， ZHANG Jiawei

2020, 41(6):  1165-1171.  doi:10.3969/j.issn.1000-1093.2020.06.013

Asbtract ( )   PDF (3421KB) ( )  

References | Related Articles | Metrics

A detection and recognition method based on the line-spectrum characteristics of shaft-rate electric field is proposed to detect the ship's shaft-rate electric field signal in ocean environment by analyzing a large number of measured data. In the proposed method, the received signal is processed by Fourier transform, and then normalized to improve its dynamic range; the dynamic and fixed thresholds are combined to detect the suspected line spectrum signal; the integral accumulation method is applied to confirm the suspected line spectrum features; and the target signal is identified by utilizing the mean characteristic of long-time integral. The validity of the proposed method is examined by the measured data in several sea trails. The results show that the proposed method can be used to detect the target effectively, and is able to recognize and classify various target signals. Key

Design and Research on Two-axis Magnet for Simulating Ship Magnetic Field

CHEN Hao， PAN Xun， XIAO Dawei

2020, 41(6):  1172-1178.  doi:10.3969/j.issn.1000-1093.2020.06.014

Asbtract ( )   PDF (2222KB) ( )  

References | Related Articles | Metrics

A two-axis magnet simulation scheme is proposed to improve the similarity of magnet used to simulate the ship's magnetic field. Wire coil and saddle coil are wound on the same core. The separate currents are used to generate two magnetic fields perpendicular to each other to simulate the ship's magnetic field. The design parameters of material, size, number of laps of coil winding are determined under the operating requirement on the ship. A physical model was made at the ratio of 10:1. The magnetic field of physical model was measured. The experimental results show that the two-axis magnet with duplex winding and single can effectively simulate the characteristics of ship's magnetic field.Key

Correction Method of Low and Medium Frequency Shock Response Spectra Based on New Measuring Device

HUI Anmin， YAN Ming， FENG Linhan， YANG Ning

2020, 41(6):  1179-1187.  doi:10.3969/j.issn.1000-1093.2020.06.015

Asbtract ( )   PDF (5496KB) ( )  

References | Related Articles | Metrics

The shock response spectrum is widely used in the design of ship and its shipborne equipment for impact resistance. Because of the existence of the trend term error, a distortion always occurs in the low frequency region of the shock spectrum. The effect mechanism of trend term error on measurement distortion in the low frequency region of shock spectrum was explained through theoretical analysis. The relationships between the magnification in the zero drift phenomenon with the natural frequency of system and the response of system were obtained. And the advantages and disadvantages of mathematical correction methods are analyzed. A new correction method of torsion pendulum correction model is proposed for the existing correction instrument, and a vibration equation of torsion pendulum model is established. And the approximate periodic solution and the main resonance frequency equation of torsion pendulum are derived by using the Ritz-Galerkin method. The maximum shock responses of the torsion pendulum and the traditional spring-mass-oscillator under the same impact environment was theoretically analyzed and test. The results show that the torsion pendulum has a good linear relationship with the spring-mass-oscillator within the swing angle of low frequency torsion pendulum less than 20.06°. By comparing the methematical correction method, traditional spring vibrator correction method and torsion pendulum correction method, it is found that the torsion pendulum has high reliability for correction results of low frequency region in the shock spectrum. Key

Gait Planning and Stability Analysis of a Quadruped Robot with 2-DOF Parallel Hip and Spine Joints

SANG Donghui， CHEN Yuan， GAO Jun

2020, 41(6):  1188-1200.  doi:10.3969/j.issn.1000-1093.2020.06.016

Asbtract ( )   PDF (13546KB) ( )  

References | Related Articles | Metrics

A quadruped robot with 2-DOF parallel hip and spine joints is proposed to solve the problems of low carrying capacity and poor walking stability. A kinematics model of standing leg and swinging legs for quadruped robot is developed based on the analytic geometry and coordinate transformation methods, and the variable of driving joint is obtained by inversely solving a foot-end position. A gait planning method of straight walking gait, fixed-point turning gait and stair climbing gait is proposed for a quadruped robot without knee joint. Based on the kinematic equations and gait planning method, the transient stability margin curve and the change curve of barycenter height in the gait cycle were got through MATLAB simulation analysis. The results show that the quadruped robot has better stability. The rationality and effectiveness of the gait planning method is verified through the robot gait test. Key

Research on Impedance Self-adjusting Control of Lower Extremity Exoskeleton during Support Phase Based onHuman Motion Ability

CHEN Jianhua， LI Ye， WANG Qi， MU Xihui

2020, 41(6):  1201-1209.  doi:10.3969/j.issn.1000-1093.2020.06.017

Asbtract ( )   PDF (5785KB) ( )  

References | Related Articles | Metrics

To solve the problem of that the impedance control of lower extremity exoskeleton during the support phase is not humanoid and its flexibility is not enough, the impedance self-adjusting control method of lower extremity exoskeleton during the support phase based on human motion ability is studied. The stiffness characteristics of human lower limber in different sub-phases of support phase were measured through the stiffness characteristic test, and the rule of non-linear change between exoskeleton impedance and actuator impedance was analyzed. An impedance self-adjusting control of lower extremity exoskeleton during support phase based on human motion ability was designed. The accurate implementation of impedance self-adjusting is ensured after gravity compensation and system friction identification. From simulation and experiment, it is found that the impedance self-adjusting method could ensure the exoskeleton’s motion to follow the preset displacement curve well and meet the flexibility requirements of different sub-phases. The research work in this paper contributes to the human-machine coupling between human and exoskeleton and the exoskeleton compliance control of the whole walking gait.Key

Effect of Graphene Additive on Microstructure and Properties of MAO Ceramic Coatings Formed on 7050 Aluminum Alloy

ZONG Yu， SONG Renguo， HUA Tianshun， CAI Siwei

2020, 41(6):  1210-1218.  doi:10.3969/j.issn.1000-1093.2020.06.018

Asbtract ( )   PDF (8589KB) ( )  

References | Related Articles | Metrics

For the corrosion and wear of 7050 high strength aluminum alloy in the marine environment, an excellent coating structure is designed to prolong its service life. The graphene-containing ceramic coating was prepared on the surface of 7050 high strength aluminum alloy by micro-arc oxidation (MAO) in a silicate electrolyte added with different concentrations of graphene. The surface morphology, roughness, phase composition, distribution of elements, bonding force and corrosion resistance of micro-arc oxidation ceramic coating are analyzed by using the scanning electron microscopy (SEM), stereomicroscope, X-ray diffractometer (XRD), X-ray photoelectron spectrometer (XPS), automatic scratch instrument for coating adhesion, electrochemical workstation, respectively. It is shown that the micro-pore size of ceramic coating which mainly consists of α-Al₂O₃, γ-Al₂O₃ decreases and its compactness is obviously improved with the addition of graphene. In addition, the roughness of ceramic coating is the lowest (857.835 nm), its adhesion is the best (46 N), and its corrosion resistance is significantly improved when the concentration of graphene is 10 g/L. The coating has maximum corrosion potential, minimum corrosion current. Key

Experimental Study of Geometric Error of Static Pressure Support-ultrasonic Vibration Single Point Incremental Forming Parts

BAI Lang, LI Yan, YANG Mingshun, LI Yuxi, LIN Yunbo, ZHAO Renfeng

2020, 41(6):  1219-1226.  doi:10.3969/j.issn.1000-1093.2020.06.019

Asbtract ( )   PDF (5803KB) ( )  

References | Related Articles | Metrics

In the single point incremental forming process, the forming process is prone to instability, and the parts are prone to wrinkle and crack due to the suspended characteristics and the springback effect of sheet. In order to solve the problems of suspension region instability and springback, it is considered to introduce static pressure support and ultrasonic vibration into the single point incremental forming for auxiliary forming. The typical truncated cone is taken as the research object. The corresponding static pressure support system and ultrasonic vibration system were designed according to the mechanism of producing the geometric errors in the axial and normal directions. The effects of static pressure support and ultrasonic vibration on axial error of part and on normal error of shape surface were studied experimentsally. The results show that the static pressure support can reduce the axial error of part by 41.98%, and the ultrasonic vibration can reduce the normal error of shape surface by 84.21%. Key

Storage Life Evaluation of Accelerometer Based on Accelerator Factor Coefficient of Variation

ZHAO Xiaodong, MU Xihui

2020, 41(6):  1227-1235.  doi:10.3969/j.issn.1000-1093.2020.06.020

Asbtract ( )   PDF (1319KB) ( )  

References | Related Articles | Metrics

Aiming at the problem that the life of accelerometers is difficult to evaluate after long-term storage, an evaluation method that comprehensively uses accelerated test data and natural storage test data was proposed. The minimum Chi-square estimation and goodness-of-fit test was used, the accelerometer's natural storage data was processed to obtain the four life distribution functions that it may obey, and the accelerometer life distribution was determined as Weibull distribution and type Ⅰ maximum distribution; With reference to the a priori information of the accelerometer, a step-by-step acceleration life test of the accelerometer is designed and carried out to obtain acceleration failure data of the accelerometer; under the assumptions of Weibull distribution and type Ⅰ maximum value distribution, the parameters of the accelerometer life distribution model are estimated based on accelerated failure data, and the method of acceleration factor variation coefficient is used to select the type Ⅰ maximum value distribution as the life distribution function of the accelerometer. The lifespan of reliability 0.90 and 0.95 under conventional stress level is 14.917 6 a and 10.052 4 a, respectively. By comparing the failure rate of accelerometers in the standard storage environment and the life distribution model, the effectiveness of using two test data to evaluate the lifespan of the accelerometer is verified. Key

Air Combat Target Threat Assessment Based on Prospect Theory

XI Zhifei, XU An, KOU Yingxin, LI Zhanwu, YANG Aiwu

2020, 41(6):  1236-1248.  doi:10.3969/j.issn.1000-1093.2020.06.021

Asbtract ( )   PDF (2557KB) ( )  

References | Related Articles | Metrics

Air combat target threat assessment is the basis of target allocation and firepower allocation. When the weight of target threat assessment indexes is determined, the correlation between the assessment indexes is not considered. And the single grey relation analysis (GRA) method and the single technique for order preferenceby similarity to ideal solution (TOPSIS) cannot accurately reflect the threat degree of target, in which the different attitudes of a pilot towards the loss and gain in the decision-making are not considered. Based on GRA and TOPSIS methods, a prospect theory and GRA-TOPSIS target threat assessment model is proposed. A concept of grey correlation depth is presented, and the weight of assessment index is determined by combining maximum entropy. The variable weight gray correlation threshold method is used to adjust the weights of assessment indexes to avoid the index-relevance effect. Finally, GRA method is used to analyze the curve shape similarity of index series, and TOPSIS method is used to analyze the position similarity. Baesd on the prospect theory, and the attitudes of pilots towards gains and losses, the threat assessment results can reflect the traits of pilots. Simulated results show the effectiveness and rationality of the proposed methods. Key