Table of Content

31 October 2015, Volume 36 Issue 10

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Paper

Falling-off Resistant Material Selection and Design of Diesel Engine Valve Seats

WANG Xiao-song， ZHANG Wei-zheng, ZHANG Ti-en, GUO Bing-bin, ZHANG Chi

2015, 36(10):  1825-1831.  doi:10.3969/j.issn.1000-1093.2015.10.001

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The falling-off cause of exhaust valve seats in a strengthened diesel engine is analyzed in terms of material selection and design. Three materials, cobalt, nickel and powder based alloy, are tested on their strengths, thermal expansion properties, friction properties and volume stabilities. The assembly interference is considered through FEM simulation, and the engine test is carried out to validate the reliability of the new material valve seat. The results show that nickel-based alloy has the lowest friction property. The volume stability of powder-based alloy is lower than that of cobalt-based alloy. Cobalt- based alloy has the highest temperature compressive and friction properties, and presents a good ability to defend the abnormal operations. Moreover, with the increase in the material strength, the assembly interference could be enhanced to 0.081~0.113 mm, with a safe coefficient of 1.4 for both cylinder head and valve seats.

Research on Driving Status Recognition of Heavy Duty Vehicle Based on Double-layer HMM Model

ZHU Tian-jun，KONG Xian-wei，LI Bin

2015, 36(10):  1832-1840.  doi:10.3969/j.issn.1000-1093.2015.10.002

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In order to detect the risky driving status of heavy duty vehicle, the double-layer hidden Markov model（HMM）is used for the rollover warning system of heavy duty vehicle, which can identify the driving status dynamically. The data is collected during the typical driving conditions, and the T-G test method is used to delete the abnormal data. The driving limit value of vehicle status is set based on K-means algorithm. Then finally Baum-Welch algorithm is used to optimize the proposed double-layer HMM, and the optimized HMM is used to identify the driving status in real-time. The identification results show that the proposed model can identify the driving status under every single driving condition as well as under the multiple driving conditions accurately and effectively. At the same time this model has a good real-time capacity.

Research on Robust Control of Gun Servo System Based on Quantitative Feedback Theory

XUN Pan-pan, HAN Chong-wei, ZHAO Yu-he, WANG Bao-hua

2015, 36(10):  1841-1846.  doi:10.3969/j.issn.1000-1093.2015.10.003

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For the low control precision problem of gun servo system induced by parameter perturbation and nonlinear disturbance factors, a robust control strategy for gun servo system based on quantitative feedback theory (QFT) is proposed. On the basis of gun servo system model with uncertain parameters, a certain gun servo system is taken as an example to show the method process, and the robust controller based on QFT is designed by using loop shaping method. System stability, tracking performance and robustness are analyzed and validated, and the system time domain response with parameter perturbation and output disturbance is studied. The research results show that the designed QFT robust controller can satisfy the performance index of gun servo system, and it has strong robustness and high tracking performance, which proves the effectiveness of the method.

Electromagnetic Compatibility Analysis of Fusillade Antiaircraft Fuze: Failure Mechanism and Using Suggestion

XIONG Jiu-liang, WU Zhan-cheng, SUN Yong-wei, GAO Le-nan

2015, 36(10):  1847-1854.  doi:10.3969/j.issn.1000-1093.2015.10.004

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To analyze the cause of the excessive early-destruction rate of a certain fuze in target practice, and slove the use problem of the fuze, an experimental method in the laboratory is advanced. The interactional effect experiments of two fuzes are done in different conditions. Interactional effect rules of fuzes are analyzed, and the failure mechanism is explained. The research results show that relative pose, relative height, relative velocity, radiation energy and radiation frequency can affect the threshold interactional distance. And the early-destruction reason is that the radiation parameters are changing when the fuzes move to each other, and the frequency pulling happens when the radiation parameters meet the requirements. The detection voltage fluctuates to lead to the mis-action of the fuze. Owing to the design technology, early-destruction can not be avoided in fusillade. But the self-destruction rate can be reduced effectively when the artilleries are positioned in a reasonable distance.

The Classification and Numerical Calculation of Noise Propagation outside Pulse Detonation Engine

HUANG Xiao-long， XU Gui-yang， WENG Chun-sheng， LI Ning

2015, 36(10):  1855-1860.  doi:10.3969/j.issn.1000-1093.2015.10.005

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The propagation of detonation noise is divided into three regions based on the nonlinear intensity to explore the mechanism of the noise propagation out of pulse detonation engine(PDE), which are strongly nonlinear region, weak nonlinear region and linear region. Three methods are used to solve the corresponding control equations. The calculated result shows that the detonation noise amplitude decays quickly at the jet. The rate of decay decreases with the increase in radial distance. The largest rate of decay is 33 dB/m in the strongly nonlinear region while the least rate of decay is 1.02 dB/m in the weak nonlinear region. The results are of great significance for studying the mechanism of detonation noise.

Dynamic Compressive Mechanical Properties of Tungstenic Reactive Material

CHEN Peng， LU Fang-yun， QIN Jin-gui， CHEN Rong， CHEN Jin， LI Zhi-bin， JIANG Bang-hai

2015, 36(10):  1861-1866.  doi:10.3969/j.issn.1000-1093.2015.10.006

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The dynamic compressive properties of reactive material at various strain rates are investigated using the split Hopkinson pressure bars(SHPB). The stress-strain curves at different strain rates are obtained under uniaxial stress loading. The stress histories are explained by the high-speed photographs to obtain the yield stress and critical reaction stress. The experimental results are fitted based on the Johnson-Cook constitutive model, and agree well with the calculated results. Numerical simulations on the dynamic compression properties are also performed using LS-DYNA with the Johnson-Cook model. The simulation results are also in good agreement with the experimental measurements, which show that the obtained model parameters can be used to describe the mechanical behavior of material well.

Design of Millimeter Wave Radiometer Hardware-in-the-Loop Simulation System

DING Yong， XIAO Ze-long， XU Jian-zhong， PENG Shu-sheng

2015, 36(10):  1867-1874.  doi:10.3969/j.issn.1000-1093.2015.10.007

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The indoor simulation is adopted instead of field experiment to minimize the experimental frequency of the millimeter wave passive detector in field. In view of the process of millimeter wave radiometer in terminal-sensitive projectile detecting armor target, a mathematical model of indoor hardware-in-the-loop simulation system is established, an equivalent mathematic model of indoor simulation system and field detection is built, and a millimeter wave radiometer hardware-in-the-loop simulation system is designed. Finally, the hardware-in-the-loop simulation results are compared with the measured results on the tower. The results show the correctness of the millimeter wave radiometer hardware-in-the-loop simulation system and the equivalent relationship of the proposed model. It can be used for the hardware-in-the-loop simulation test for the development and production test of terminal sensitive projectiles.

Dynamic Characteristics Simulation of Projectile-borne Device Based on Split Hopkinson Pressure Bar

QIAN Li-zhi, NING Quan-li, LI Jun, JIANG Bin-an

2015, 36(10):  1875-1881.  doi:10.3969/j.issn.1000-1093.2015.10.008

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In order to study the mechanism of projectile-borne devices against high overload, the sustainable limit load of projectile-borne device and the output stress on projectile-bornre device after load shedding are got by SHPB device and high speed camera. For the deformation of load shedding subassembly due to stress wave effect and strain rate effect coupling under shock, a nonlinear dynamic model of the projectile-borne device with load shedding subassembly is established based on the nonlinear properties of viscoelastic material. The material property of load shedding subassembly can be got by parameter identification and compatibility relationship of characteristic line, the experimental result is well consistent with the theoretical calculation. The model provides the theoretical research and method for the dynamic characteristics of projectile-borne device in high-overload environment.

Experimental Study on Spray Characteristic of Air-assist Swirl Nozzle in Confined Space

LIU Kun, YU Yong-gang， ZHAO Na

2015, 36(10):  1882-1887.  doi:10.3969/j.issn.1000-1093.2015.10.009

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To investigate the spray characteristic of an air-assist swirl nozzle in confined space,the distributions of Sauter mean diameter (SMD) and axial velocity of droplets are measured, respectively, using laser phase Dopper analyzer (PDA). The spray parameters in atmospheric environment and confined space are compared and analyzed. The results indicate that the mean diameter of droplets is determined by liquid pressure and gas pressure. With the increase in the distance between the measuring point and the nozzle, the mean diameter of droplets increases firstly and then decreases, and the axial velocity of droplets decreases. When the liquid pressure is constant and the gas pressure improves, the mean diameter of droplets decreases and the axial velocity increases. When the gas pressure is constant and the liquid pressure improves, the mean diameter of droplets increases while the axial velocity changes slightly.

Effect of Radome Parasitic Loop and On-line Compensation of Self-tuning Control

ZONG Rui, LIN De-fu, FAN Shi-peng, LAN Ling

2015, 36(10):  1888-1898.  doi:10.3969/j.issn.1000-1093.2015.10.010

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A radome parasitic loop model is established for the design of guidance system in radar homing missiles. The effects of radome parasitic loop on thestability and guidance performance parameters of guidance system are analyzed by using thedimensionless method. A real-time compensation for radome parasitic loop is proposed based on the theory of pole placement self-tuning control, and a simulation is performed. The research results indicate that the radome error slope leads to parasitic loop, which weakens the stability of guidance system, and deteriorates the stability when the time-to-go decreases. The parasitic loop may change the effective guidance time constant and effective navigation ratio of guidance system, thus reducing the guidance accuracy. The compensation method can make the parasitic loop be compensated effectively with good adaptability and robustness so that the stability and performance of guidance system are improved.

Entry Trajectory Tracking of RLV Based on Fuzzy Variable Structure Control

HU Yu，WANG Hua, REN Zhang

2015, 36(10):  1899-1906.  doi:10.3969/j.issn.1000-1093.2015.10.011

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To reduce the dependence of trajectory tracking of reusable launch vehicle (RLV) on the aerodynamic parameters and initial conditions, and improve the robustness of traditional control method, a new entry trajectory tracking method based on the fuzzy variable structure is proposed from the perspective of longitudinal tracking guidance. Also, a method of on-line planning the point of the bank angle reversal is designed in the aspect of lateral trajectory control. The simulation results show that the longitudinal tracking control method which is based on the fuzzy variable structure can track the designed trajectory perfectly and stably, and has strong robustness in the condition of big initial state error and aerodynamic coefficient error. The online searching of the bank angle reversal point can be realized by using the proposed lateral guidance method, which can also improve the lateral guidance accuracy effectively.

Measurement Method of Spacecraft Attitude Angular Rate Based on Magnetically Suspended Control Moment Gyroscope

WANG Ping， WANG Hua， REN Yuan

2015, 36(10):  1907-1915.  doi:10.3969/j.issn.1000-1093.2015.10.012

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For the problem of abnormal position control, which is produced by separation of measure and control, in the existing attitude control system, a spacecraft attitude angular rate method based on magnetically suspended control moment gyroscope is proposed. A dynamic model of magnetically suspended control moment gyroscope with pyramid configuration is established, and the integrated measurement and control mechanism of spacecraft based on magnetically suspended control moment gyroscope is analyzed according to the theorem of inertia moment. An analytical expression of attitude angular velocity is obtained through joint solution of 3 magnetically suspended control moment gyroscopes in pyramid configuration . Simulation results verify the correctness and superiority of this method.

The Test of Tracking Accuracy and Design of Airborne Laser Communication Stabilized Pod

MENG Li-xin, ZHAO Ding-xuan, ZHANG Li-zhong, JIANG Hui-lin, LI Xiao-ming

2015, 36(10):  1916-1923.  doi:10.3969/j.issn.1000-1093.2015.10.013

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For the optical axis stability problem of airborne laser communication, a coarse and fine tracking system is proposed. The installation structure of the shock absorber is analyzed. Avibration reduction system is designed, and the servo system is simulated. On this basis, the vibration and movement characteristics of the aircraft are measured. The measured results meet the laboratory simulation input. The simulation tests and the field tests of tracking accuracy are carried out. The reults show that, under the condition of atmospheric channel, the tracking accuracy of coarse tracking system is better than 23.97 μrad, and the tracking accuracy of fine tracking system is better than 7.03 μrad. The results are greater than the laboratory simulation test results, which provide a reference for the system index allocation and the improvement of pod accuracy.

A RPHT-TBD Algorithm for Tracking and Detecting Maneuvering Weak Target via Airborne PD Radar

YU Hong-bo， WANG Guo-hong， ZHANG Zhong-kai

2015, 36(10):  1924-1932.  doi:10.3969/j.issn.1000-1093.2015.10.014

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To address the problem of maneuvering weak target detection and tracking with airborne pulse Doppler(PD) radar in medium and high PRF modes, a novel randomized parabolic Hough transform algorithm（RPHT） is proposed within the framework of track-before-detection (TBD). The ambiguous measurements are mapped into all the possible range ambiguity intervals by a multiple hypothesis ranging procedure, where the space-time relevance can be derived. RPHT is used to integrate all the information along the target trajectory in the parameter space. And an azimuth transformation method is introduced to RPHT, which significantly reduces the computational complexity of this algorithm. In such a way, the new approach transforms the problem of range ambiguity resolution into the decision of the real track for weak targets. Simulation results illustrate its effectiveness.

Modeling and Error Characteristics Analysis of Celestial Attitude Determination Error Based on Geometric Configuration ofGuide Stars

WANG Li-na, ZHAO Hui, XIONG Zhi, YU Feng, SHI Li-juan

2015, 36(10):  1933-1942.  doi:10.3969/j.issn.1000-1093.2015.10.015

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As the basic element of celestial attitude determination, the geometric distribution of guide stars has a great impact on the performance of celestial navigation system. In order to analyze the error characteristics of celestial attitude determination,an error model based on basic celestial attitude determination principles is established by adopting the method of multi-vectors attitude determination, and the weighting coefficients are provided for assessment. Taking tri-star observation for example, the error model is verified by applying digital simulation. The proposed model can be used to analyze the performance of celestial attitude determination effectively, providing theoretical basis for error characteristics analysis.

AUV’s Bottom Following Control Method Based on ADRC

WAN Lei， ZHANG Ying-hao， SUN Yu-shan， LI Yue-ming

2015, 36(10):  1943-1948.  doi:10.3969/j.issn.1000-1093.2015.10.016

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To make sure an autonomous underwater vehicle (AUV) have better resistance to the interference of the external environment and its own signal transmission, a bottom-following control method based on active disturbance rejection control (ADRC) is offered. The control method can transform the bottom-following control into pitch control and be designed with an AUV’s motion protection mechanism. In the simulation, a three-dimensional motion control, which is based on the proposed method, is made to simulate the whole process of AUV finishing the bottom-following task from the surface to the sea bottom. And it is compared with the control method based on PID. The results show that the ADRC-based bottom-following control method can fulfill the scheduled tasks accurately. Compared with PID, the new method has better control results, and can effectively suppress the overshoot and shake caused by interference.

Calculation of Aerodynamic Heating and Ablation of Multi-layer Thermal Protection Material

ZHANG Zhi-hao, SUN De-chuan

2015, 36(10):  1949-1954.  doi:10.3969/j.issn.1000-1093.2015.10.017

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It is inevitable to evaluate the aerodynamic heat and the ablation of thermal protection material for designing a hypersonic aircraft. A coupling method is presented for the calculation of aerodynamic heat, material ablation and transient temperature distribution. The method and program are validated by experimental data. The results indicate that the method has higher precision and efficiency. For a given trajectory, the aerodynamic heat, ablation performance of thermal protection layer and temperature filed are predicted by the coupling method. The proposed method can be used to calculate the ablation and temperature distribution in given operation conditions in design phase which is referable for the design of multi-layer thermal protection material for hypersonic aircrafts.

Interface Structure and Anti-ballistic Mechanism of TiB₂/Ti-6Al-4V Graded Armor Composites

SONG Ya-lin, ZHANG Long, ZHAO Zhong-min, PAN Chuan-zeng

2015, 36(10):  1955-1961.  doi:10.3969/j.issn.1000-1093.2015.10.018

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The TiB₂/Ti-6Al-4V graded armor composites are prepared by metallurgically bonding of TiB₂ and Ti alloy in ultra-high gravity field for promoting the protection efficiency of armored vehicles, and the effect of interface structure on the ballistic performance is analyzed through the results of XRD and FESEM, DOP experiment and numerical simulation. XRD and FESEM results show that the graded microstructures exist at a joint which is characterized by the size and the distribution of TiB₂ phases and TiB phases. The protection coefficients of TiB₂ based ceramic and TiB₂/Ti-6Al-4V graded armor composites are calculated to be 3.05 and 7.30, respectively, by DOP experiment. Compared with TiB₂ based ceramic, the ballistic performance of TiB₂/Ti-6Al-4V graded armor composites greatly increases. It is considered that the graded microstructure at the joint of TiB₂/Ti-6Al-4V effectively reduces the acoustic impedance mismatch and increases the shear strength of the joint, and finally enhances the ballistic performance of the target against a projectile.

Determinatio of Specific Heat Capacity of Fiber and Resin Matrix Composites by Micro-calorimeter

MENG Xiang-yan， LIU Yun-chuan， ZHOU Yan-ping， WANG Xue-rong， WANG Kang，

2015, 36(10):  1962-1966.  doi:10.3969/j.issn.1000-1093.2015.10.019

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In order to study a method of determining the specific heat capacity of fiber and resin matrix composites by micro-calorimeter, the sensitivity curve of micro-calorimeter is determined by Joule effect. The specific heat capacity of standard sample α-Al₂O₃ in the range of 30～150 ℃ is obtained by micro-calorimeter , and the maximum difference between their test values and literature values is 2.41%. The measuring accuracy of the method is high. And the continuous specific heat capacities of carbon fiber and three kinds of resin matrix composites are gained by using the method. The results show that the micro-calorimeter could accurately and conveniently determine the continuous specific heat capacities of fiber and compound materials and also the change regulation of specific heat capacities with temperature. The change regulations of c_p of fiber and resin matrix composites are discussed.

Simulation of Measuring Method for Space-time Distributed Parameters of Multiple Projectiles

WU Jiang-peng， SONG Ping， HAO Chuang-bo， LI Zhi-da

2015, 36(10):  1967-1974.  doi:10.3969/j.issn.1000-1093.2015.10.020

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For the measuring difficulty of the vertical target dispersion when multiple projectiles impact simultaneously, a measuring method for the space-time parameters of multiple projectiles is proposed by using two CCD vertical targets. There is an angle between two CCD target surfaces in vertical direction. When several projectiles arrive at target surface Ⅰ at the same time, the projectiles in the non-horizontal direction are separated on target surface Ⅱ because they fly over different distance between two CCD targets. The projectiles in the horizontal direction cannot be separated and are matched in accordance with the principle of pixels order matching. The impact coordinates of multiple projectiles with sequence and flight velocity can be calculated through the coordinates projection and the temporal-spatial matching from Target Ⅱ to Target Ⅰ. The simulation result proves that the proposed method can effectively address the issue of eliminating the false projectiles on single CCD target when multiple projectiles impact all at once.

The Contact Analysis of Helical Gear in Considering Gear Shaft Deformation

BAI En-jun， XIE Li-yang， TONG An-shi， BAI Xin

2015, 36(10):  1975-1981.  doi:10.3969/j.issn.1000-1093.2015.10.021

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A finite element model for transmission is developed for the contact analysis of helical gear in considering gear shaft deformation. The finite element method and model are validated by using the finite-difference method to calculate the deformation of gear shaft and the ISO 6336-1 standard to calculate the mesh stiffness. The distribution of contact force along the tooth width, tooth von Mises stress, tooth root bending stress and contact force of each tooth pair during meshing process are obtained from two finite element models of rigid and flexible shafts. Contact ratio and mesh stiffness are performed between two gear teeth at different contact positions during meshing process. The results show that the deformation of gear shaft affects the tooth load distribution along the tooth width, increases contact ratio, and decreases the mesh stiffness.

Rolling Bearing Performance Degradative State Recognition Based on Mathematical Morphological Fractal Dimension andFuzzy Center Means

WANG Bing, LI Hong-ru, CHEN Qiang-hua, XU Bao-hua

2015, 36(10):  1982-1990.  doi:10.3969/j.issn.1000-1093.2015.10.022

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In allusion to the degenerative state recognition of rolling bearing, a performance degenerative recognition method based on mathematical morphological fractal dimension (MMFD) and fuzzy center means (FCM) is proposed by combining mathematical morphology and fuzzy assemble theory. MMFD is calculated for the performance degenerative feature of rolling bearing to describe its complexity and irregularity in the view of fractal. In consideration of the fuzziness among different performance degradation boundaries, FCM is introduced into fuzzy clustering for characteristic index, and the performance degradation could be recognized effectively in line with maximum subordinate principle. The fatigue life enhancement test of rolling bearing was carried out to gather the whole life data at Hangzhou Bearing Test & Research Center. The method is applied to the whole life data of rolling bearing, the overall state successful recognition rate reachs 96%. The results show that the method has a small calculating cost and a high efficiency, and can efficiently identify the performance degenerative state of rolling bearings.

Simulation and Sensitivity Analysis of Collaborative Developing Process of Weaponry Based on Quality Feedback

YIN Wei-wei, JIANG Ju, XIN Jun-jie

2015, 36(10):  1991-1999.  doi:10.3969/j.issn.1000-1093.2015.10.023

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Among three performance indicators, such as time of duration, cost and quality, of a project, the quality is very important. To make the completion quality of the subtask achieve the prospective quality indicator, the process of rework is described by means of quality-feedback based on design structure matrix. Monte Carlo simulation technique is applied to obtain the total cost and time of the project. In this way, the time of duration, cost and quality are linked together to study the influence of quality on schedule risk and cost risk of the project through the analysis of the sensitivity. The research results show that the sensitivity of airframe structure design task is the highest in the process of advanced development of a certain military aircraft, so the project manager can give priority to control the process risk by coordinating the allocation of resources.

Research on Power Tracking Control Strategy of Current Power Generation System

MAO Zhao-yong, HUANG Wei-chao, FAN Yu

2015, 36(10):  2000-2005.  doi:10.3969/j.issn.1000-1093.2015.10.024

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In order to solve the problem of maximum energy capture in the dynamic change of current, the research of maximum power point tracking(MPPT) control strategy of an extensible vertical-axis blade current power generation system is carried out. Based on the analysis of the current equation of motion of power generation system, an optimal torque control strategy is proposed based on second-order sliding mode using the output torque as the feedback signals to solve the existing problems of MPPT, like the precise measurement of current velocity and the complicated design of control system. The simulation results show that the power control device and control system can dynamically track the maximum power point, and have good dynamic characteristics and control effect. The stability and effectiveness of the control strategy are verified.

Research Notes

Method of Vehicle Speed Estimation Adapted in All Conditions for All-wheel Independent Drive Vehicle

YANG Gui-bing, LI Chang-bing, LIAO Zi-li, MA Xiao-jun, LIU Chun-guang

2015, 36(10):  2006-2011.  doi:10.3969/j.issn.1000-1093.2015.10.025

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A speed estimating method adapted in all conditions based on the parameter adaptive Kalman filter is established for speed estimation of the all-wheel independent drive vehicle. The left and right sides are estimated separately, and the parameters of filter are adaptively adjusted by fuzzy controller. An adaptive switching condition is designed based on drive condition and road adhesion condition. The accelerating integral is chosen when the anti-slip of the tire is higher than the preset default value. The effectiveness and accuracy of the speed estimating method are verified through hardware-in-loop real-time simulation. The simulation results show that the proposed method possesses high estimation precision under many operating condistions, and has general application value.

Synthesis and Characterization of a Novel Energetic Compound 1-Methyl-35-dinitropyrazole-4-nitrate

FENG Xiao-qin, CUI Jian-lan, CAO Duan-lin

2015, 36(10):  2012-2016.  doi:10.3969/j.issn.1000-1093.2015.10.026

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In order to seek high performance energetic compounds, a novel energetic material, 1-methyl-3,5-dinitropyrazole-4-nitrate, is synthesized using 4-chloropyrazole as raw material via nitration, nucleophilic substitution, and methylation reaction . Its structure is characterized by FTIR, NMR and elemental analysis. The effect of reaction time and dosage of iodomethane on methylation reaction is investigated, and the better synthesis condition is obtained. The reaction temperature is 40 ℃, the reaction time is 10 h, and the dosage of iodomethane is twice of that of DNPN with a yield of 55.2%. Its detonation properties are calculated and compared with those of other commonly-used energetic compounds. The results show that the detonation properties of 1-methyl-3,5-dinitropyrazole-4-nitrate are slightly lower than those of TNAZ and better than those of TNT. The impact sensitivity of 1-methyl-3,5-dinitropyrazole-4-nitrate is higher than that of TNAZ and similar to that of RDX.