Table of Content

31 December 2014, Volume 35 Issue 12

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Paper

Analysis and Experiment of Lubrication Condition of Rotary Seal Based on Two Cavitation Boundary Conditions

ZHAO Yi-min, WEI Chao, YUAN Shi-hua

2014, 35(12):  1937-1943.  doi:10.3969/j.issn.1000-1093.2014.12.001

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For JFO and Reynolds cavitation boundary conditions, a theoretical lubrication condition model of spiral-groove rotary seal is established. Lubrication state transitions are analyzed by theoretical model based on different cavitation conditions. In the mixed lubrication state, the asperity contact properties are described by fractal contact model. The results show that Reynolds boundary condition can be used to predict larger fluid carrying capacity, but apparently underestimate the cavitation area especially in high speed conditions; In steady operating state, JFO boundary condition can be used to predict higher separation speed which makes the rotary seal transfer from mixed lubrication to hydrodynamic lubrication. The experimental results indicate that the theoretical leakages of two cavitation boundary conditions and the experimental results have the same variation tendency. However, compared with Reynolds boundary condition, JFO boundary condition is used to predict smaller leakages, which are more close to the experiment results, particularly in high speed condition.

Electric Differential Control of Electric Drive Tracked Vehicle with Linear Active Disturbance Rejection Control

MA Xiao-jun, ZENG Qing-han, YUAN Dong, LIU Chun-guang, WEI Shu-guang

2014, 35(12):  1944-1950.  doi:10.3969/j.issn.1000-1093.2014.12.002

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The driving cycle of tracked vehicle is so complex, and the drive motor with wide speed range runs under nonlinear, uncertain and strong coupling load. How to control the motor speed to improve the stability of steering has become a research hot point. An electric differential control strategy is put forward. And the LADRC control algorithm is used in speed control of PMSM system, and LESO is used to estimate and compensate the unknown disturbance, thus rejecting the disturbance and improving the dynamic performance of system. The collaborative model of Matlab and RecurDyn softwares and test bench are built. The simulation and experimental results show that the speed control strategy with LADRC can be used to achieve rapid response without overshoot, strong disturbance rejection and good parameter adaptability, which improve the vehicle stability.

Research on Initial Alignment of SINS on Swaying Base through Velocity Measurement in Different Coordinates

ZHAO Hong-song, MIAO Ling-juan, SHEN Jun, ZHANG Xi

2014, 35(12):  1951-1958.  doi:10.3969/j.issn.1000-1093.2014.12.003

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Two alignment models are proposed to solve the adverse effect of lever arm on initial alignment of strapdown inertial navigation system (SINS) on a swaying base. In the proposed method, the difference between SINS output velocity and lever arm velocity is taken as a measurement and two measurement equations are established separately for navigation frame and body frame. The characteristics of the two alignment models are analyzed. It is demonstrated that the alignment model in navigation frame is only suitable for the case of having lever arm length with a certain precision. On this basis, a filtering method for feedback correction of filter parameters is presented to improve the adaptability of the alignment mo-dels and the alignment accuracy. The simulation results show that the two alignment models are available, and the filtering method is effective for feedback correction of filter parameters.

Electric Load Simulator Control Based on a Novel Wavelet Neural Network and Grey Prediction

WANG Chao, LIU Rong-zhong, HOU Yuan-long, GAO Qiang, WANG Li

2014, 35(12):  1959-1966.  doi:10.3969/j.issn.1000-1093.2014.12.004

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A new type of wavelet neural network and grey prediction control strategy is proposed for the complex nonlinearity of some artillery servo system of electric load simulator and the influence of extra torque on the system. The control strategy is mainly composed of a variable structure wavelet neural network controller with particle swarm optimization and a grey prediction compensator(GPC). The variable structure wavelet neural network controller optimizes the parameters of wavelet neural network with particle swarm optimization(PSO) to speed up the convergence of the system, and changes the number of hiden neurons using the self-learning algorithm dynamically to reduce the calculation complexity and improve the dynamic and static performances of the system. The grey prediction compensator is constructed based on the stability of the system in the sense of Lyapunov, which predicts the input torque deviation and further improves the stability and accuracy of the system. The hardware-in-the-loop simulation results show that the hybrid control strategy has strong robustness and high control precision and ensures the stability and anti-interference ability of the system under dynamic load.

An Initial Velocity Model of Explosively-driven Cubical Fragments

YIN Li-kui, JIANG Jian-wei, MEN Jian-bing, WANG Shu-you

2014, 35(12):  1967-1971.  doi:10.3969/j.issn.1000-1093.2014.12.005

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In order to build a model to predict the initial velocity of explosively-driven cubical fragments, the simulation is carried out to analyze the explosive driving process by using AUTODYN hydrocode. The explosive driving process is divided into two stages, i.e., leakage and non-leakage of detonation product. A model of cubical fragment velocity is established by theoretical derivation based on a series of hypothesis, impulse theorem and modified gas pressure formula. The results are well consistent with the experiment results. The results show that the number and deformation of fragments have influence on the initial velocity of fragment.

Research on In-situ Charge and Performance of Si-based Micro-detonator

XIE Rui-zhen, LIU Lan, REN Xiao-ming, ZHANG Fang, LI Xian-lin, JIN Zhen-shu

2014, 35(12):  1972-1977.  doi:10.3969/j.issn.1000-1093.2014.12.006

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The chip integration of MEMS (Micro-electromechanical system) safety and arming devices has a requirement to develop a miniature detonator technology , and the charge of detonator needs high sensitivity and large detonator output because of its small size. The in-situ preparation of energetic materials is used for researching the charge of Si-based micro-detonator, and the firing energy actually utilized by Si-based micro-detonator is explored using the current loop. Firing sensitivity is tested based on GJB/Z377A—1994 sensitivity test methods:Langlie, and the output is also qualitatively tested. The result shows that 50% of firing sensitivity is 7.89 V at 33 μF, and the detonator output can initiate CL-20.

Quantitative Inspection of Ammunition Density by Industrial CT Imaging

LYU Ning， XU Geng-guang， XUE Tian， HUANG Qiu-an

2014, 35(12):  1978-1982.  doi:10.3969/j.issn.1000-1093.2014.12.007

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Modeling and decladding corrections are adopted to research the edge effect of shell inthe quantitative inspection of charge density of medium and large caliber ammunition by industrial CT imaging. The accuracy of density comparison model can be improved. The test results show that the accuracy of decladding correction methodis better than that of modeling correction method for charge density inspection of ammunition. The proposed methods can be used for the inspection of local charge density by industrial CT imaging.

Research on Prediction Model for Forecasting the Yawing of Projectile

LYU Zhen-jian, YUAN Jian-hu, LU Ming, CHEN Liu-hai

2014, 35(12):  1983-1990.  doi:10.3969/j.issn.1000-1093.2014.12.008

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The study on the change rule of projectile attitude is important in improving either the attacking capability of projectiles or the protective capability of projects. The dynamics process of projectile subjected to deflecting force is discussed, and the change rule of motion parameters is analyzed. An in-depth study is given to the phenomena of which a projectile strikes and penetrates the metallic cone, and a mo-del for forecasting leading-yaw performance of solid cone is established. The difference between yawing processes of solid cone and hollow cone is analyzed, and a model for forecasting yawing performance of hollow cone is founded with a correction modulus applied on that of solid cone. The experimental verification of the model for hollow cone proves that the computational results are in good agreement with the experimental results.

Numerical Research on Secondary Muzzle Flash Using Gridless Method

WU Wei, XU Hou-qian, WANG Liang, XUE Rui

2014, 35(12):  1991-1997.  doi:10.3969/j.issn.1000-1093.2014.12.009

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The secondary muzzle flash, involving high-speed projectile, is numerically studied using a least-square gridless method. The fluid dynamics is modeled by arbitrary Lagrangian-Eulerian equations with chemical source term. The numerical flux and chemical kinetics are dealt with by multi-component HLLC scheme and the finite rate chemical model. A restructuring technique is adopted to dispose the freaky clouds due to the moving boundaries. The full flow fields are simulated to examine the effects of potassium salt flame suppressors and muzzle pressure on the muzzle flash. The computational shadowgraph is in good agreement with experimental shadowgraph. The results show that 2% addition in potassium salt or 30% reduction in muzzle pressure may inhibit the secondary muzzle flash effectively.

Experimental Research on Curved Trajectory of High-speed Water-entry Missile

WANG Yun, YUAN Xu-long, LYU Ce

2014, 35(12):  1998-2002.  doi:10.3969/j.issn.1000-1093.2014.12.010

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The experiment about the four geometries are carried out. A digital high-speed camera is used to record the evolution of the water-entry process and cavity shapes. The flat-trajectory curves of the four different geometries are obtained, and the effects of the head shape, entry angle and velocity on the trajectory are analyzed . The results show that the projectile body with oval-beveled warhead is easier to form the curved trajectory because of its special warhead. The other three kinds of trajectories are more stabilized. When it is at certain speed range, the trajectories verge to be linear; when it is at a higher speed, the trajectory may be curved. The effect of entry angle on the trajectory is obvious. When the entry angle is little, its trajectory deflects to the free surface quickly; when it is larger, the trajectory deflects to the bottom of the cylinder. The conclusions provide reference for the research on the water-entry weapons.

Analysis of Non-line-of-sight Imaging Characteristics Based on Laser Range-gated Imaging

XU Kai-da, JIN Wei-qi, LIU Jing, GUO Hui, QIU Su, LI Li, ZHAO Shen-you

2014, 35(12):  2003-2009.  doi:10.3969/j.issn.1000-1093.2014.12.011

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Laser range-gated imaging systems can obtain the images of targets hidden around a corner by using an intermediary reflective surface with certain specular reflection characteristics. This imaging mode is called non-line-of-sight imaging. The target signal irradiance and disturbance radiation on the photo-detector of a non-line-of-sight imaging system are analyzed based on the modeling of an intermediary reflective surface, and an image contrast model of a non-line-of-sight imaging system is constructed. The effects of the reflective characteristics of an intermediary reflective surface and the distance between the intermediary reflective surface and the target or the detector on the image quality are analyzed in terms of the parameters of a typical non-line-of-sight imaging system. The simulation results show that a laser range-gated imaging system is indispensable for non-line-of-sight imaging with commonly used intermediary reflective surfaces without significant specular reflection characteristics, and the distance of the intermediary reflective surface from the target has a significant effect on the non-line-of-sight imaging. When the locations of detector and target are fixed, the non-line-of-sight imaging system can hardly identify the target if the intermediary reflective surface is closer to the target. In practice, the performance of the non-line-of-sight imaging system can be maximized using an appropriate usage strategy.

Research on Working Condition of Electromagnetic Actuator of Trajectory Correction Projectile with Decoupled Canards

CHENG Jie, YU Ji-yan, WANG Xiao-ming, YAO Wen-jin

2014, 35(12):  2010-2015.  doi:10.3969/j.issn.1000-1093.2014.12.012

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The canard and bearing are dynamically modeled to improve the dual-spin trajectory model based on Euler approach. The working condition of electromagnetic actuator of trajectory correction projectile with decoupled canards (TCPDC) is investigated. The designed working condition is validated by the parameters derived from the dual-spin trajectory. The spin-rate and electromagnetic torque of actuator are extracted based on the rolling states of projectile and canards. The calculated results indicate that the canards spin in relative to the opposite direction of projectile body rapidly after launch, and then spin down at a relatively low and stable rate, which is hardly affected by the launching conditions. The spin rate of projectile is the main factor, which leads to a large range of actuator’s working speed. After the projectile flies through an apogee, the spin rate of actuator could be stably maintained between 130 and 230 r/s, and the essential torque is less than 0.5 N·m. In terms of the working range of actuator, the optimal starting control point should be in the segment behind the apogee.

ANFIS-based Predictive Reentry Guidance for Hypersonic Vehicles

RAN Mao-peng, WANG Qing, MO Hua-dong, DONG Chao-yang

2014, 35(12):  2016-2022.  doi:10.3969/j.issn.1000-1093.2014.12.013

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An adaptive neuro-fuzzy inference system (ANFIS) based predictor-corrector guidance is proposed for the nonlinearity of the reentry kinematic equations of hypersonic vehicles. The energy-based three degrees of freedom reentry kinematic equations are established, and the longitudinal and lateral guidance laws are designed. For the longitudinal guidance, an ANFIS controller is designed by taking energy and range error as system inputs and bank angle variation as system output. The lateral guidance is based on the approximate linearity between crossrange and energy. A lateral reversal logic based on the cross range corridor is designed. Simulation results show that the proposed guidance law has the advantages of less calculating time and high guidance precision, and is not sensitive to the initial errors and disturbances.

Sensitivity Analysis of Design Bandwidth of Missile Three-loop Acceleration Control

SUN Ming-wei, ZHANG Li-min, CHEN Zeng-qiang

2014, 35(12):  2023-2029.  doi:10.3969/j.issn.1000-1093.2014.12.014

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Because the aerodynamic uncertainties of a missile are distributed in the coupling subsystems for the popularly used three-loop acceleration autopilot, the traditional stability margins are unable to illustrate the robust range of the closed-loop system in relative to the uncertain characteristic parameters.The acceleration control is parameterized by using a design bandwidth, and then the closed-loop sensitivity of the restoring and manipulation moment coefficients with regard to this bandwidth is investigated in a unified manner by means of the D-decomposition method. The robust stability of the closed-loop system is described. The numerical examples demonstrate that the proposed method can provide the accurate robust stability boundary of the closed-loop system to the primary uncertain factors, revealing the variation rule of the sensitivity of the bandwidth to statically unstable and stable missiles. The key factor in determining the crucial angular velocity gain is also specified as the manipulation moment coefficient.

Three-dimensional Path tracking Guidance and Control for Unmanned Aerial Vehicle Based on Back-stepping andNonlinear Dynamic Inversion

LIU Zhong, GAO Xiao-guang, FU Xiao-wei, XI Wen-qing

2014, 35(12):  2030-2040.  doi:10.3969/j.issn.1000-1093.2014.12.015

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In order to realize the three-dimensional path tracking guidance and control for unmanned aerial vehicle (UAV), a new path tracking guidance and control method is presented, which separates the vehicle guidance and control problems into an outer guidance loop and an inner control loop. In outer guidance loop, the problem of tracking reference path is transformed to the tracking of a virtual vehicle by using a virtual vehicle which moves along the reference path for the real aircraft to track. A nonlinear guidance law is proposed based on the back-stepping method. In inner control loop, the flight control is designed based on the nonlinear dynamic inversion (NDI) theory and the time scale separation (TSS). The flight control can follow the commands generated by the outer guidance loop fleetly and accurately, which includes maneuver command generator, angle calculator, slow loop attitude angles control and fast loop attitude angle rate control.The stability of system is proved based on Lyapunov stability theory. Six degrees of freedom (6-DOF) simulation results illustrate that UAV can track three-dimensional path accurately, and demonstrate the feasibility and reasonability of the proposed method.

Research on Ballistic Missile Tracking Based on Adaptive Markov Parameter IMM

FENG Pu-wen， HUANG Chang-qiang， CAO Lin-ping， XIANG Meng， REN Yang

2014, 35(12):  2041-2049.  doi:10.3969/j.issn.1000-1093.2014.12.016

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How to consecutively track the boost phase and coast phase transitions without any prior information has become a pressing issue. Solving the problem with interacting multiple model is a feasible method. Since the Markov parameter of conventional interacting multiple model is constant, the model switching slows down. An adaptive Markov parameter IMM (AMP-IMM) algorithm is developed based on the modification of posterior information. The Markov transition probabilities can be modified adaptively in the process of filtering by omitting the information of non-matching model and magnifying the matching model information simultaneously during switching. The algorithm accelerates system convergence speed. Simulation results show that the proposed algorithm can consecutively track BM from the boost phase to the coast phase and is more effective than the conventional interacting multiple model.

The Simulation Analysis and Experiment Research of Turbine Aerodynamic Force

YU Guo-bin, YU Guang-wei

2014, 35(12):  2050-2057.  doi:10.3969/j.issn.1000-1093.2014.12.017

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A calculation method of turbine efficiency is proposed in order to study the influence of turbo inlet hose diameter, inlet gap and other factors on the turbine performance , as well as verify the difference between the simulated and test results.The aerodynamic characteristics of the flow field are simulated and analyzed with the help of simulation software. The results show that the simulated results are in agreement with the test results. The start-up transient flow field of impact-type turbine is relatively complex. Inlet angle is a key to affect the start-up efficiency of the turbine. The efficiency of the turbine can be improvedby reducing the gaps of turbine and selecting the throat diameter that matches with the flow.

Research on Flow Field Structure of Ventilated Supercavity around an Axisymmetric Body

DUAN Lei, WANG Guo-yu, ZHANG Min-di

2014, 35(12):  2058-2064.  doi:10.3969/j.issn.1000-1093.2014.12.018

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To understand the flow field structure of ventilated supercavity，the ventilated cavity flows around an axisymmetric body are researched by the experimental and numerical methods. A filter-based turbulence model is applied to accurately capture the vortex separation in numerical simulations. The methods of Euler and Lagrangian Coherent Structures (LCS) are used to describe the flow field structure in the domain of ventilated supercavity. The results show that the numerical results are consistent with the experimental results. The air entrained from the ventilated hole transports along the air-water interface to the end of cavity. Some portions of air escape from the domain of cavity, while some portions of air flow into the domain of cavity by the reentrance. The air existing in the middle of ventilated cavity moves regularly and cannot escape from the cavity. Some portions of fluid in the rear of ventilated cavity escape from the cavity and form the shedding bubbles, while some portions of fluid vortically move in the cavity.

A Numerical Simulation of Seismic Wave Caused by Low Frequency Sound Source in Shallow Sea with Thick PorousSediment by Staggered-grid Finite Difference Method

LU Zai-hua, ZHANG Zhi-hong, GU Jian-nong

2014, 35(12):  2065-2071.  doi:10.3969/j.issn.1000-1093.2014.12.019

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Elastic wave in the seabed caused by low frequency noise radiated from ship is the so-called ship seismic wave which can be used to identify ship target. In order to obtain the propagation characteristics of ship seismic wave in shallow sea with thick porous sediment, a 3D staggered grid finite difference algorithm for calculating seismic wave at seafloor is presented based on Biot wave theory for porous elastic sediment. Numerical calculation of seismic wave caused by low frequency sound source in a typical shallow sea environment is carried out. The calculated results show that the components of seismic wave in the near field include not only fast P-wave, slow P-wave and S-wave transmitted into the sediment, but also an interface wave which propagates nearby the seafloor. However in the far field, the wave components of seismic wave are mainly normal modes and interface wave, the former propagates mainly in the waveguide of sea water and the latter propagates along the seafloor.

Influence of Blast Shock on Shielding Effectiveness of Electromagnetic Shielded Enclosure with Integral Shock Isolation

HUANG Liu-hong, HE Yong-sheng, LI Yue-bo, LIU Feng, HE Wei

2014, 35(12):  2072-2077.  doi:10.3969/j.issn.1000-1093.2014.12.020

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Shielding effectiveness of electromagnetic shielded enclosure would be decreased by blast shocks. An electromagnetic shielded enclosure with the shock isolator with own patented technology is designed and constructed. The field blasting and shielding performance tests are conducted to study the effect of blast shock on the the shielding effectiveness of electromagnetic shielded enclosure with integral shock isolation. The results show that the vibration acceleration of electromagnetic shielded enclosure with integral shock isolation is only 18 m/s² although the input vibration acceleration peak is up to 115 m/s² under the blast shocks of 160 kg cumulative charge. This means that the integral shock isolation effectively reduces the impact of blast shock on electromagnetic shielded enclosure. The electromagnetic shielded enclosure meets the requirement of GradeⅠ.

Micro-gripper for Precision Meso-scale Assembly

SUN Yuan， JIN Xin, YE Xin， ZHANG Zhi-jing， ZHANG Xiao-feng

2014, 35(12):  2078-2086.  doi:10.3969/j.issn.1000-1093.2014.12.021

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Meso-scale parts are widely used in the complex miniature weapon systems. On account of a large dimension range, a variety of shapes and vulnerable structures of the meso-scale parts, the weapon systems are mainly assembled by hand, bringing poor efficiency and reliability. A challenging issue in the precision assembly of miniature weapon systems is how to safely and reliably grip the meso-scale parts in the automatic handling and assembly. A micro-gripper for gripping the sub-millimeter and millimeter scale shafts and parts is developed, including a pair of rigid and flexible gripping jaws and a precision linear motion stage. A Wheatstone bridge, which consists of strain gauges stuck on the flexible gripping jaw, is used to detect a clamping force on a part in real time. The structural parameters of flexible gripping jaw are designed optimally, and an optimal design model of gripping jaws is proposed. A simulation analysis is carried out to determine the best sticking positions of the gauges. A strain-force model for the special shape of flexible gripping jaw is derived. Grip-release experiments indicate that the micro-gripper is capable to grip the meso-scale parts stably and nondestructively.

Multi-noise Model-based Denoising Method for Radiographic Image

SHEN Qing-ming， WANG Guo-bo， ZHAO Jian-zhong， XU Guan-li

2014, 35(12):  2087-2091.  doi:10.3969/j.issn.1000-1093.2014.12.022

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A multi-noise model-based denoising method for radiographic image is proposed, in which wavelet transform and median filtering are used. The composition of the image noise is analyzed, and a multi-noise model is established. The variance of noise is calculated in terms of the multi-noise model, and then the BayesShrink threshold is calculated , which solves the problem of that the Donoho’s noise algorithm is invalidated since the wavelet coefficients do not obey the generalized Gaussian distribution. A median filtering is used to refine the result obtained by the wavelet transform to eliminate the image distortion caused by the BayesShrink thresholding. Radiographic images are used to verify the effectiveness of the proposed method. Experiments show that the performance of the proposed method is better than those of OracleShrink and SureShrink.

Research on the Positioning Method of Multi-optical Theodolites Based on Hermite Function Restriction

GONG Zhi-hua， XU Xu， DUAN Peng-wei， LEI Hong

2014, 35(12):  2092-2097.  doi:10.3969/j.issn.1000-1093.2014.12.023

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The direction cosine location method which is used in traditional optical geometric intersection is simple, so it is widely used in engineering practice. But this method is greatly influenced by the geometric relationship, and cannot inhibit the measuring error, so its positioning accuracy is unsatisfactory. In addition, it cannot be used to compute the locations with more than three stations at a time. A new positioning method with multi-optical theodolites is proposed based on Hermite function restriction. This method can be called function restricted EMBET method. This method uses Hermite function to express the positioning parameters to compress the number of parameters to be estimated, and meanwhile the measuring elements of optical theodolite can be expressed. The measuring equation can be formed by measuring data of multiple measuring elements. Based on least square criterion, the positioning parameters are obtained by computing the combined equation, and the system errors of measuring elements are calibrated. Through the calculation of simulated example, the function restricted EMBET method is compared with the direction cosine location method. The result shows that the function restricted EMBET method is more accurate and more practical.

A Reliability Modeling Approach to Avoiding Mis-specification of Pseudo Life Distribution in CSADT

XU Ting-xue, WANG Hao-wei, ZHANG Lei

2014, 35(12):  2098-2103.  doi:10.3969/j.issn.1000-1093.2014.12.024

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A reliability modeling approach based on parameter conversion is proposed to avoid the mis-specification of pseudo-life distribution in constant stress accelerated degradation test (CSADT). The proposed method models the parameters of degradation path functions. It is different from the traditional method that models the parameters of distribution functions. The pseudo life of all samples under the working stress is evaluated, and the distribution type can be accurately identified. A application example with the CSADT data of carbon-film resistors is provided. The research results show that the proposed method can effectively resolve the problem of mis-specification of pseudo-life distribution.

Analysis of Dynamic Wear Reliability of Mechanism under Stochastic Noise

ZHANG Feng, NAN Hua, YAO Hui-ju, LYU Cheng-cheng

2014, 35(12):  2104-2108.  doi:10.3969/j.issn.1000-1093.2014.12.025

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A dynamic wear reliability model for a mechanism is established based on stochastic dynamics theory and the failure probability is estimated. On the basis of traditional wear analysis,

The Optimization Selection of Tests Based on Greedy Algorithm

LIU Jian-min, LIU Yuan-hong, FENG Fu-zhou, JIANG Peng-cheng

2014, 35(12):  2109-2115.  doi:10.3969/j.issn.1000-1093.2014.12.026

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A novel test selection method is proposed based on greedy algorithm, which is used for fault detection and isolation, to overcome the shortcomings of the traditional test optimization algorithms, such as poor universality. The method is used to select the required test with aim of the minimal number of tests. Then the optimal test is selected gradually by greedy search. Finally, the validity of the proposed method is verified by using the binary-value and multi-value test optimization cases. Theoretical and case studies show that the proposed method is not only effective to excavate the fault detection and isolation ability of tests with low time complexity, but also applicable to the binary-value and multi-value test optimization of isolating the fauts to replaceable unit and specific failure mode.

Maintenance Task Scheduling Model Considering Rest Time and its Solving Algorithm

LYU Xue-zhi， CHEN Le， YIN Jian， FAN Bao-xin

2014, 35(12):  2116-2123.  doi:10.3969/j.issn.1000-1093.2014.12.027

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As the maintenance resources are periodically used, namely, they must have rest after running for a period of time, a maintenance task usually is urgent, which must be going on without interruption, how to give out maintenance task scheduling plan and rest times of maintenance resources at same time is an issue being worth to be discussed. A hybrid integer-programming model is established based on the model assumption. A PSO-based solving algorithm is proposed, which includes algorithm framework, particle representation, resources-skills allocation algorithm, particle decoding algorithm and update methods. The validity and feasibility of the model and resolving algorithm are verified by an example.

Research Notes

An Evaluation Method of Ballistic Consistency under Small Sample Circumstance

ZHANG Ling-ke, ZHAO Feng, YU Yong-gang

2014, 35(12):  2124-2128.  doi:10.3969/j.issn.1000-1093.2014.12.028

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In order to evaluate ballistic consistency under small sample circumstance, an evaluation method of ballistic consistency is proposed based on the normal distribution small sample compatibility theory. This method is to compare the calculated order statistics and the simulated critical value to determine the ballistic consistency. The main advantage is not necessary to calculate the position- scale estimate value, so it could decrease the calculation error due to small sample size. The calculation shows that this method is better than matched pair t test and probability circle sequential test under small sample circumstance (n≤5).