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2018, 38(10): .

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2018, 38(10): .

Abstract(586) PDF(335)

Abstract:

Design of Structure Resisting High Overloads for Spinning Micro-Machine's Rotating Rack in Fuse

HUI Jiang-hai, GAO Min, LI Xin-peng

2018, 38(10): 991-999. doi:10.15918/j.tbit1001-0645.2018.10.001

Abstract(954) PDF(741)

Abstract:
Instantaneous high overload that appears during projectile's launch process always results in the failure of spinning micro-machine's rotating rack used for trajectory correction fuse, rendering the fuse unable to work normally. In view of such a problem, combined with the design method of resisting overloads for onboard device, based on the rotating rack's dynamic model and bearing's energy absorption principle under the condition of buffer design, the bearing's overload characteristic was acquired through finite element dynamic simulation based on projectile-barrel-fuse coupling with the operating characteristic of machine's rotating rack concerned. The results indicated that the axial inertial force was the main load imposed on bearings. On this basis, two schemes, adding the buffer made of copper and changing the size in shaft shoulder and bottom bolt, were proposed. Then the ball bearings's maximal stress variation during projectile's launch process was acquired by finite element dynamic simulation based on projectile-barrel-fuse coupling. The results indicated that the buffer cannot reduce the maximal stress to below the bearing steel's yield strength. However, the bearings's maximal stress can be reduced to below the bearing steel's yield strength. Through determination of thrust bearing's deformation, this scheme can meet the needs of resisting overloads in the design of the rotating rack, and ensure normal operating of the micro-machine's power generation after launch process.

Research on Failure Rule and Dynamic Response of Tunnel Under Adjacent Blasting Loads of Different Spacing

GUO Dong-ming, LIU Kang, ZHANG Wei, YANG Jun, FAN Long-fei, XUE Lei

2018, 38(10): 1000-1005. doi:10.15918/j.tbit1001-0645.2018.10.002

Abstract(1002) PDF(507)

Abstract:
Experimental research and numerical analysis are effective methods for researching failure rule and dynamic response of tunnel under adjacent blasting loads of different spacing. Through experimental research, the following results were found. When spacing was smaller, the side facing blasting showed triangle-shaped damage. The back side of blasting side showed crack growth of sprung arch and base angle with the increase of spacing, the failure degree became lower. The research was conducted using the software LS-DYNA. When explosive mass remained the same, the vibration velocity of sprung arch decreased by exponential function with the increase of spacing. When the spacing was less than 3D, the peak velocity of attenuation was faster and the peak value of vibration velocity was larger than safe vibration velocity, which was very dangerous. When the spacing was larger than 3D, the peak velocity of attenuation was slower and the spacing was safe. The largest region of vibration velocity peak value was located in the range from the middle part to sprung arch, and then the bottom of stalk and arch.

Prediction of Safe Blasting Vibration Velocity of an Earth Dam Based on FLAC^3D

LI Sheng-lin, LIU Zhi-yuan, ZHANG Hui-ge, MENG Ling-hao

2018, 38(10): 1006-1011. doi:10.15918/j.tbit1001-0645.2018.10.003

Abstract(902) PDF(426)

Abstract:
Based on a large amount of on-site blasting vibration monitoring and signal analysis, the approximate viscous damping ratio of the earth dam was obtained, and the quasi-two-dimensional model of an earth dam was established based on the dynamic response characteristics of the dam by FLAC^3D. The Rayleigh wave distribution of the dam foundation was obtained based on the calculation and simplification of soil mechanical parameters, and the main frequency of the dam body was determined. The frequency of the most unfavorable seismic waves was 2.00 Hz. The velocity threshold of dam damage was 16 cm/s by increasing the amplitude of the worst seismic waves, and the threshold was taken as the safe vibration velocity of the dam, which effectively guaranteed the safety of the dam. In this paper, dam vibration speed was predicted by FLAC^3D, which can be referred to and used by production and scientific research units.

Study of the Crater Produced by Hypervelocity Tungsten Alloy Projectile into Concrete Target

QIAN Bing-wen, ZHOU Gang, LI Jin, ZHANG De-zhi, ZHANG Xiang-rong, ZHU Yu-rong, JING Ji-yong, TAN Shu-shun, LI Yun-liang

2018, 38(10): 1012-1017. doi:10.15918/j.tbit1001-0645.2018.10.004

Abstract(1217) PDF(569)

Abstract:
In order to explore the cratering mechanism of concrete targets undergoing hypervelocity impact, experiments were carried out by two-stage light gas gun with Gram-grade cylindrical tungsten alloy projectiles, impacting concrete targets at velocities from 1.97 to 3.66 km/s. Experimental data of crater were obtained by computerized tomography (CT). Dimensionless analyses based on point source solution were used to further analyze the mechanism of hypervelocity impact. The results showed that: the craters were structured by spalling areas and bullet holes; the body penetration stage occupied a large proportion of the total penetration depth, so that the penetration depth was not positively related to the kinetic energy. The dimension of the cubic crater diameter and the crater volume are proportional to the kinetic energy of the projectiles, which indicates that the cratering process is mainly affected by the kinetic energy.

Experiment and Numerical Simulation of Ablation on Aluminum Target with High-Intensity Laser

WU Jun-ying, YANG Li-jun, WU Bao, WANG Long, CHEN Lang

2018, 38(10): 1018-1024. doi:10.15918/j.tbit1001-0645.2018.10.005

Abstract(1022) PDF(479)

Abstract:
In order to study the damage of high-intensity laser ablation to aluminum targets, a series of experiments with different laser energies were conducted. A high-speed schlieren photography technique with a double-pulse laser as background light source was used to observe the flow field of laser ablation on aluminum. The ablation characteristics of the aluminum target under different laser energies were obtained. A two-dimensional computation model for high-intensity laser ablation on aluminum targets was established, and the processes of pulse laser ablation on aluminum targets with different energies were conducted. The influences of the pulse laser energy on ablation depth were obtained. Numerical simulation of the process of continuous laser ablation of aluminum targets with large light spot was conducted. The ablation depth and ablation morphology under gravity and no gravity were compared and analyzed. The results show that the ablation depth under gravity is less than that without gravity, and the ablation area is greater than that without gravity.

Study on Numerical Simulation and Application of Blasting of Tunnel Excavation

SUN Bao-ping, GAO Wen-xue, ZHOU Shi-sheng

2018, 38(10): 1025-1029,1036. doi:10.15918/j.tbit1001-0645.2018.10.006

Abstract(813) PDF(415)

Abstract:
To investigate fragmentation of rock and vibration of millisecond delay under multi-hole blasting, full restart method of numerical simulation and Lagrangian formula were taken to simulate the fragmentation of rock and the vibration of tunnel excavation. The vibration velocity of the characterized place in the rock was attained. The results of numerical simulations showed agreement with experiments. The results indicate that combining the full restart method of numerical simulation and Lagrangian formula could simulate the vibration and fragmentation of rock blasting.

A Method of Policy Automated Generation for Carrier Aircraft Sortie and Recovery Scheduling

YANG Fang-qing, WANG Chao, JIANG Bin, ZHANG Xiu-yuan

2018, 38(10): 1030-1036. doi:10.15918/j.tbit1001-0645.2018.10.007

Abstract(816) PDF(517)

Abstract:
To improve the capability of carrier aircrafts sortie and recovery, a theory of apprenticeship learning, came of the robot navigation and control domain, was applied to automate the process of sortie and recovery scheduling. Firstly, a simulation model of aircrafts sortie and recovery was established based on the frame of Markov decision process. Then, taking an expert's demonstration operation as learning former, an optimized scheduling policy was created with the multiplicative weights apprenticeship learning algorithm. Compared with the optimization results of the two typical research cases in the condition of group sortie and continuous sortie with the expert's demonstration, the algorithm shows a better performance and function.

The Re-Entry Orbit Design Algorithm Based on an Adaptive Radau Pseudo-Spectral Method

ZHANG Heng-hao

2018, 38(10): 1037-1045. doi:10.15918/j.tbit1001-0645.2018.10.008

Abstract(869) PDF(553)

Abstract:
To solve the problems of low accuracy and poor efficiency of the traditional Radau pseudo-spectral method in dealing with non-smooth surfaces, an adaptive Radau pseudo-spectral method was proposed to generate the optimal re-entry orbit. The algorithm could adjust the intervals adaptively according to the approximation precision of state equations. In regions of relatively high curvature, the accuracy was increased by dividing a segment into more mesh intervals, whereas in regions of relatively low curvature, accuracy was increased by increasing the degree of the approximating polynomial within a mesh interval. Simulation results show that the nodes distribution generated by the adaptive Radau pseudo-spectral re-entry orbit design algorithm is more reasonable and efficient than that of the traditional Radau pseudo-spectral method. The algorithm can be applied to re-entry orbit design in practical engineering due to its high efficiency and high precision.

Multi-Constellation Protection Level Optimization Method Using Genetic Algorithm

ZHENG Xue-en, XU Cheng-dong, FAN Guo-chao, ZHAO Jing

2018, 38(10): 1046-1050. doi:10.15918/j.tbit1001-0645.2018.10.009

Abstract(675) PDF(369)

Abstract:
Advanced receiver autonomous integrity monitoring (ARAIM) algorithm can provide constellation integrity protection for a vehicle in a precision approach segment. To improve the availability of ARAIM in China, a vertical protection level (VPL) optimization method based on genetic algorithm was proposed. This method deduced the maximum function minimization problem into the optimal problem of target planning at the theoretical level. To avoid singular values, genetic algorithm was used to solve the optimization equation, and the VPL value was optimized by optimally assigning continuity risk and integrity risk. In order to verify the effectiveness of the optimization method, the VPL was calculated by using the satellite ephemeris data of GPS, GLONASS and BDS collected in the tracking station. The results show that the average optimization rate of the proposed method is 9.9%.

Research on Hopping for Hydraulic Robot Leg via the Variable Stiffness Control

ZHAO Jiang-bo, XUE Ta, WANG Jun-zheng

2018, 38(10): 1051-1055. doi:10.15918/j.tbit1001-0645.2018.10.010

Abstract(654) PDF(458)

Abstract:
The hydraulic legged robot has been widely concerned because of its strong load capacity and excellent dynamic performance.In this paper,the hydraulic robot leg was investigated based on the spring-loaded inverted pendulum (SLIP) model to solve the energy regulation and hopping control problem for hydraulic robot.And an active variable stiffness control strategy was proposed to adjust the energy of hydraulic robot leg in the stance phase and ensure its desired hopping height.The experimental results show that the control strategy proposed in this work can achieve a stable hopping for the hydraulic foot robot leg and control its hopping height effectively.

Key Gait Parameter Optimization for Hydraulic Quadruped Robot

HAN Bao-ling, ZHU Chen, LUO Qing-sheng, ZHAO Rui, WANG Qing-qiang

2018, 38(10): 1056-1060. doi:10.15918/j.tbit1001-0645.2018.10.011

Abstract(751) PDF(478)

Abstract:
Focusing on the foot trajectory planning of quadruped robot,a method to improve the stability of robot was proposed by optimizing the step-height and step-length gait parameters.An experimental design was carried out based on the aggregation cross method,and simulation and verification were carried out with Matlab and Adams.A three-dimensional surface was fitted with the speed,step size and the corresponding evaluation function value obtained by simulation,and then the optimal step length at different speeds could be obtained from the curved surface.The dichotomy was used to obtain the step-height interval to meet the evaluation index.The simulation results show that the gait planning based on the gait parameters obtained by the proposed method could make the robot achieve static gait with better motion performance.

Volume Multi-Source Images Registration Based on Improvement Model Fitting and Adjustment

ZHANG Yan, SUN Shi-yu, LI Jian-zeng, HU Yong-jiang

2018, 38(10): 1061-1066. doi:10.15918/j.tbit1001-0645.2018.10.012

Abstract(745) PDF(337)

Abstract:
In order to improve the accuracy of volume multi-source images registration, a volume multi-source images registration was proposed based on improvement model fitting and adjustment (VMIRIMFA). Firstly, fast adaptive robust invariant scalable feature detector (FARISFD) and robust overlapped gauge feature descriptor (ROGFD) was used to enhance the robustness of feature registration. Then, improved random sample consensus was proposed to ensure the robustness of the algorithm and to improve the operation efficiency. Finally, an adjustment method was proposed for volume multi-source images registration and result optimization. The experiment results show significant advantages of VMIRIMFA in terms of precision for multi-source images with the large difference.

Tracking Control for Uncertain Rehabilitative Training Walker with Velocity and Acceleration Simultaneous Constraints

SUN Ping

2018, 38(10): 1067-1072. doi:10.15918/j.tbit1001-0645.2018.10.013

Abstract(717) PDF(359)

Abstract:
In order to solve the uncertainty problem caused by different rehabilitee mass and the center of gravity shift, affecting the tracking precision of the rehabilitative training walker in accordance with the doctor prescribe training programs, a filter was designed to estimate the uncertainty and improve the robust performance of control system. Considering the sudden shift of motion velocity and acceleration during training, a new method was proposed for the control system design to restrain the uncertainty and restrict the velocity and acceleration simultaneously. The constraint condition of velocity and acceleration was established in Lyapunov stability,validating the asymptotic stability of the tracking error system, and obtaining the solution method for parameter matrices. Comparing the simulation and experiment results, it is showed that the motion velocity and acceleration of the rehabilitative training walker can be constrained simultaneously. The results validate the effectiveness and advantage of the proposed design method for control system.

Dual-Loop Attitude Tracking Control with Differential Observer

YIN Chun-wu

2018, 38(10): 1073-1078,1084. doi:10.15918/j.tbit1001-0645.2018.10.014

Abstract(706) PDF(326)

Abstract:
A dual-loop attitude tracking robust controller was presented for rigid spacecraft to deal with the attitude tracking control problem. Attitude dynamic equation was decomposed to two independent subsystems by presetting a bounded virtual angular velocity. The preset virtual angular velocity in outside loop was used to ensure the attitude asymptotical converge to desired attitude,and was taken as a virtual input of inner loop subsystem. The uncertainty composed of rotational inertia perturbation, external disturbance and exceed saturated amplitude could be estimated by second-order differential observer accurately. Then,an observation value based attitude controller was designed to make the real angular velocity exponential converge to virtual angular velocity. Analysis results show that, the dual-loop attitude tracking controller can satisfy the constraints of bounded angular velocity and control saturation,present higher tracking accuracy and robustness.Numerical simulation results validate the robustness and effectiveness of the dual-loop attitude tracking controller.

A Parameter Adaptive Gaussian Mixture CQKF Algorithm Under Non-Gaussian Noise

MENG Dong, MIAO Ling-juan, SHAO Hai-jun, SHEN Jun

2018, 38(10): 1079-1084. doi:10.15918/j.tbit1001-0645.2018.10.015

Abstract(882) PDF(357)

Abstract:
A Gaussian mixture filtering method under non-Gaussian noise environment was studied, and the target tracking of pure azimuth tracking system was carried out. Firstly, a modified parameter adaptive method was used to adjust the size of the displacement parameter, so the Gaussian mixture model could be modified. The parameter adaptive Gaussian mixture CQKF algorithm (PGM-ACQKF) under non-Gaussian noise was proposed. Then based on the discrete system model under non-Gaussian noise, the limitations of the modeling process in the Gaussian mixture CQKF (GM-CQKF) was analyzed. Combining with the initial optimization method, a method to modify the Gaussian mixture model was proposed based on parameter adaptive method. Thus the limitations of GM-CQKF could be overcome and the filtering accuracy could be improved. The simulation results show the effectiveness of the proposed algorithm, which proves that the PGM-ACQKF has higher filtering accuracy than the original algorithm under non-Gaussian noise.

Design of Stable System of Long Trace Profiler

YANG Bin, GAO Jun-xiang, LI Ming, TANG Shan-zhi, YANG Fu-gui

2018, 38(10): 1085-1090,1095. doi:10.15918/j.tbit1001-0645.2018.10.016

Abstract(660) PDF(740)

Abstract:
Analyzing the influence of the temperature gradient,air disturbance,vibration and drift error on the measurement accuracy of the long trace profiler (LPT),a stable system was designed for the LPT,that body made mainly with double deck Aluminum alloy material and a closed shield structured with interlayer water cycle cover.To improve the stability of the system,several measures were introduced,for example,designing the closed structure and increasing solder joints of the interlayer to reduce the influence of air disturbance;selecting Aluminum alloy materials with good thermal conductivity and circulating water system to improve the temperature stability;taking the graphite thermal film for the inner wall paste to avoid local excessive temperature rise and improve the temperature distribution uniformity.The ANSYS software was used to check the structural strength of the stable system,optimize the distribution of solder joints,and further improve the structural stiffness.The actual tests of the K-B mirror samples show that,the measurement accuracy of the LTP device with stable system is higher and less noise for surface shape measure.Performance test of the self collimator installation shows that,the noise of autocollimator with stable system can be efficiently suppressed,greatly improve the detection performance.

Design and Simulation of Raman-Mie Polarization Lidar System for Particle Depolarization Ratio Measurement

CHEN Si-ying, TIAN Yi-shan, CHEN He, ZHANG Yin-chao, GUO Pan

2018, 38(10): 1091-1095. doi:10.15918/j.tbit1001-0645.2018.10.017

Abstract(978) PDF(357)

Abstract:
In order to solve the influence of atmospheric molecular signal on the echo signal of Mie-polarization lidar, a pure rotational Raman-Mie polarization lidar was designed for particle depolarization ratio measure. The echo signal and the SNR simulation results show that, the maximum detection distance can reach 12 km at night, verifying the feasibility of the system. The particle depolarization ratio profile was calculated by correcting the polarization signal with Raman signal. Comparing the depolarization ratio profiles in different weather conditions, it was found that this system was more suitable for the measurement of high altitude cirrus clouds and aerosol particles with smaller concentration but larger depolarization.

Study on Statistical Distribution of Proton Radiation Process

HU Hai-yun, WANG Bin-rong, YOU Yan-hua, YANG Xiao-li

2018, 38(10): 1096-1100. doi:10.15918/j.tbit1001-0645.2018.10.018

Abstract(660) PDF(371)

Abstract:
In order to study the effect of proton with some energy in different penetration depth on material properties,a non-equilibrium statistical model of proton irradiation process was established based on the randomness of collisions during passing process to get the passing growth rate function and penetration depth probability density function respectively for high energy and low energy proton.Taking the proton irradiated Kapton film as an example, the analysis results show that,the product of the most probable penetration depth of high-energy proton and its corresponding maximum probability density is a fixed value;but with the energy increasing of the low energy proton,the product of the most probable penetration depth of low-energy proton and its corresponding maximum probability density is gradually reduced to a certain value;by contrast, it is found that the energy demarcation line between high energy proton and low energy proton is about 10⁵eV.

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