JOURNAL OF BEIJING INSTITUTE OF TECHNOLOGY

Fuzzy Logic Control for Semi-Active Suspension System of Tracked Vehicle

GUAN Ji-fu, GU Liang, HOU Chao-zhen, WANG Guo-li

2004, 13(2): 113-117.

[Abstract](257) [PDF 188KB](24)

Abstract:
The model of half a tracked vehicle semi-active suspension is established. The fuzzy logic controller of the semi-active suspension system is constructed. The acceleration of driver's seat and its time derivative are used as the inputs of the fuzzy logic controller, and the fuzzy logic controller output determines the semi-active suspension controllable damping force. The fuzzy logic controller is to minimize the mean square root of acceleration of the driver's seat. The control forces of controllable dampers behind the first road wheel are obtained by time delay, and the delay times are determined by the vehicle speed and axles distances. The simulation results show that this control method can decrease the acceleration of driver's seat and the suspension travel of the first road wheel, the ride quality is improved obviously.

Analysis of the Spectral Resolving Power in Tomographic Imaging Spectrometry

FANG Jun-yong, ZHAO Da-zun, JIANG Yue-juan

2004, 13(2): 118-122.

[Abstract](263) [PDF 187KB](20)

Abstract:
From the point of view of design requirements, influence of the width of the output image of an imaging subsystem in a tomographic imaging spectrometer, namely width of the slit, the grating and the size of the CCD pixel are analyzed. For the tomographic imaging spectrometry, if the amplification ratio of the imaging subsystem is not high enough to make the whole object to be compressed within the slit, then either the slit width should be increased or the slit width kept unchanged but scanned to receive information of the object. While the width-increase method reduces the spectral resolving power and the SNR; the scanning method reduces the SNR. Analysis of the two cases and computer simulation results are given.

Influence of the Plasma State on the Formation of Nano Crystalline SiC Films

LIAO Bo, WANG Jing-jing, LU Shan-shan, YAN Hui, WANG Bo

2004, 13(2): 123-126.

[Abstract](218) [PDF 156KB](21)

Abstract:
The influence of the plasma state on the microstructure transformation from amorphous to nano-(crystalline) state is emphasized during the formation of the silicon carbide (SiC) films deposited by the plasma enhanced chemical vapor technique. The effect of two key parameters, the working pressure and hydrogen concentration in the gas flow, that perform the dependence by modulating the two essential factors of the plasma state-ions energy and gas composition, is in-depth investigated. The experimental results showed that nanocrystalline SiC films fit for field emitters could be achieved under an appropriate ion energy flow density and gas components in the (plasma).

Small-Scale CMOS Pseudo SRAM Module Design

LI Yun, LIU Zhen-yu, HAN Yue-qiu

2004, 13(2): 127-130.

[Abstract](182) [PDF 174KB](22)

Abstract:
An approach to design small scale CMOS static random access memory (SRAM) is proposed. The design of address decoder, memory cell, and the layout are included. This approach adopts flip-flop array structure. The flip-flops are used as the storage cells and they are stacked to form the whole SRAM module. The word select bit is generated from the address decoder. And one word at a time is selected for reading or writing. The design of the memory core's layout is also discussed since it should be optimized to save area and also should be convenient for realization. It's a full-custom layout. The address decoder is composed of combinational logic circuit and its layout is also designed as a full-custom layout. With all these modules, the integral structure of the SRAM is carried out.

Parameter Estimation of Time-Varying ARMA Model

WANG Wen-hua, HAN Li, WANG Wen-xing

2004, 13(2): 131-134.

[Abstract](275) [PDF 207KB](20)

Abstract:
The auto-regressive moving-average (ARMA) model with time-varying parameters is analyzed. The time-varying parameters are assumed to be a linear combination of a set of basis time-varying functions, and the feedback linear estimation algorithm is used to estimate the time-varying parameters of the ARMA model. This algorithm includes 2 linear least squares estimations and a linear filter. The influence of the order of basis time-(varying) functions on parameters estimation is analyzed. The method has the advantage of simple, saving computation time and storage space. Theoretical analysis and experimental results show the validity of this method.

Radial Basis Function Neural Network Based Super- Resolution Restoration for an Undersampled Image

SU Bing-hua, JIN Wei-qi, NIU Li-hong

2004, 13(2): 135-138.

[Abstract](268) [PDF 213KB](30)

Abstract:
To achieve restoration of high frequency information for an undersampled and degraded low-resolution image, a nonlinear and real-time processing method-the radial basis function (RBF) neural network based super-resolution method of restoration is proposed. The RBF network configuration and processing method is suitable for a high resolution restoration from an undersampled low-resolution image. The soft-competition learning scheme based on the k-means algorithm is used, and can achieve higher mapping approximation accuracy without increase in the network size. Experiments showed that the proposed algorithm can achieve a super-resolution restored image from an undersampled and degraded low-resolution image, and requires a shorter training time when compared with the multiplayer perception (MLP) network.

New Realization Method for Airborne SAR Motion Compensation

SU Hong-yu, LI Shu, LI Fang-hui, LONG Teng

2004, 13(2): 139-142.

[Abstract](290) [PDF 162KB](18)

Abstract:
After analyzing the characteristics of airborne SAR motion deviation in detail, a new realization method for airborne SAR motion compensation based on two-dimensional division processing is described. By combining the division of local tracks in azimuth direction and the division of sub-mapping strips in range direction, the motion deviation will be compensated accurately. Furthermore, both theoretic analysis and simulation result show that by using this method the problems of motion compensation under complex condition with large motion deviation and large mapping strip width can be resolved well.

Enhanced Pattern Representation in Information Extraction

LIAO Le-jian, CAO Yuan-da, ZHANG Ying-bo

2004, 13(2): 143-147.

[Abstract](314) [PDF 175KB](19)

Abstract:
Traditional pattern representation in information extraction lack in the ability of representing domain-specific concepts and are therefore devoid of flexibility. To overcome these restrictions, an enhanced pattern representation is designed which includes ontological concepts, neighboring-tree structures and soft constraints. An information-(extraction) inference engine based on hypothesis-generation and conflict-resolution is implemented. The proposed technique is successfully applied to an information extraction system for Chinese-language query front-end of a job-recruitment search engine.

Modeling and Simulation of Time Series Prediction Based on Dynamic Neural Network

WANG Xue-song, Cheng Yu-hu, PENG Guang-zheng

2004, 13(2): 148-151.

[Abstract](274) [PDF 153KB](22)

Abstract:
Molding and simulation of time series prediction based on dynamic neural network(NN) are studied. Prediction model for non-linear and time-varying system is proposed based on dynamic Jordan NN. Aiming at the intrinsic defects of back-propagation (BP) algorithm that cannot update network weights incrementally, a hybrid algorithm combining the temporal difference (TD) method with BP algorithm to train Jordan NN is put forward. The proposed method is applied to predict the ash content of clean coal in jigging production real-time and multi-step. A practical example is also given and its application results indicate that the method has better performance than others and also offers a beneficial reference to the prediction of nonlinear time series.

Camera Self-Calibration in Computer Vision with Precise Estimation of Initial Parameters

PEI Ming-tao, YU Lian-qing, LIU Peng, JIA Yun-de

2004, 13(2): 152-156.

[Abstract](228) [PDF 203KB](22)

Abstract:
A key problem that plagues camera self-calibration, namely that the classical self-calibration algorithms are very sensitive to the initial values of the camera intrinsic parameters, is analyzed and a practical solution is provided. The effect of the camera intrinsic parameters, mainly the principal point and the skew factor is first discussed. Then a practical method via a controlled motion of the camera is introduced so as to obtain an accurate estimation of these parameters. Feasibility of this approach is illustrated by carrying out comprehensive experiments using synthetic data as well as real image sequences. Unreasonable initial values can often make self-calibration impossible, yet a precise initialization guarantees a better and successful reconstruction. Trying to obtain a more reasonable initialization is worthwhile the effort in camera self-calibration.

Application of Improved Neural Adaptive PSD Algorithm in Temperature Control of INS

MIAO Ling-juan, GUO Zhen-xi, CUI Yan

2004, 13(2): 157-160.

[Abstract](260) [PDF 152KB](19)

Abstract:
A neural adaptive proportion sum differential (PSD) algorithm with errors prediction is researched. It is applied in inertial navigation system(INS) temperature control. The algorithm do not need the process's precise mathematical model and can adapt to the process parameters changing, and can deal with the process with nonlinearity. According to the Smith predictor, author developed a method that takes the predicted process error and error change as neural adaptive PSD algorithm's input. The method is effective to the system with long dead time. The results of compute simulation show that this system has characters of quickly reaction, low overshoot and good stability. It can meet the requirements of temperature control of INS.

Slab Tracking and Controlling on Hot Plate Rolling Line

YAO Xiao-lan, DENG Bo, LIANG Qi-hong, LI Bao-kui

2004, 13(2): 161-164.

[Abstract](190) [PDF 168KB](19)

Abstract:
By studying the slab moving in detail in the plate rolling process, the problem of slab tracking and controlling was solved by using the distributed control system. The problems of rhythm control for the big-complex system, the exchange of manual and automatic operations, the data exchange between the levelⅠ, TCS (technology control system) and levelⅡ, PCS (process control system), are solved. By this way, the automatic level of the plate production line is improved.

Lighting Model of the Real World in Augmented Reality

ZHOU Ya, YAN Da-yuan, ZHAO Hu

2004, 13(2): 165-168.

[Abstract](364) [PDF 176KB](16)

Abstract:
Construction of a lighting model of the real world is one of the critical aims in an augmented reality (AR) system. The theory of lighting modeling used in computer graphics(CG) is applied in this study. The position of the real light-source is first conjectured from light and shade of the registration image element by element using a ray tracking algorithm. Then the virtual light-source and virtual fiducial are constructed in the CG environment, in which, the Phong model is used to draw the light effect. By comparing the CG scene with the real image, one can modify the parameters of the lighting model over and over again, until the lighting effect of the CG scene is close enough to that of the real image. It is proved that this method works well in the indoor AR system. The method can be used feasibly in most applications with some improvements.

Clone Selection Algorithm with Niching Strategy for Computer Immune System

ZHANG Ya-jing, HOU Chao-zhen, XUE Yang

2004, 13(2): 169-173.

[Abstract](270) [PDF 175KB](18)

Abstract:
A clone selection algorithm for computer immune system is presented. Clone selection principles in biological immune system are applied to the domain of computer virus detection. Based on the negative selection algorithm proposed by Stephanie Forrest, combining mutation operator in genetic algorithms and niching strategy in biology is adopted, the number of detectors is decreased effectively and the ability on self-nonself discrimination is improved. Simulation experiment shows that the algorithm is simple, practical and is adapted to the discrimination for long files.

Effect of Center High Explosive in Dispersion of Fuel

ZHANG Qi, LIN Da-chao, BAI Chun-hua, GUO Yan-yi

2004, 13(2): 174-178.

[Abstract](225) [PDF 183KB](25)

Abstract:
The dispersion of the fuel due to the center high explosive, including several different physical stages, is analyzed by means of experimental results observed with a high speed motion analysis system, and the effect of center high explosive charge is suggested. The process of the fuel dispersion process can be divided into three main stages, acceleration, deceleration and turbulence. Within a certain scope, the radius of the final fuel cloud dispersed is independent of the center explosive charge mass in an FAE (fuel air explosive) device, while only dependent both on the duration of acceleration stage and on that of the deceleration. In these two stages, the dispersion of the fuel dust mainly occurs along the radial direction. There is a close relation between the fuel dispersion process and the center explosive charge mass. To describe the motion of fuel for different stages of dispersion, different mechanical models should be applied.

Projectile-Borne Video Reconnaissance System

WANG Hai-fu, ZHANG Feng, LI Xiang-rong

2004, 13(2): 179-182.

[Abstract](277) [PDF 161KB](20)

Abstract:
Aiming at applications as a projectile-borne video reconnaissance system, the overall design and prototype in principle of a mortar video reconnaissance system bomb were developed. Mortar launched test results show that the initial integrated system was capable of transmitting images through tens of kilometers with the image resolution identifying effectively tactical targets such as roads, hills, caverns, trees and rivers. The projectile-borne video reconnaissance system is able to meet the needs of tactical target identification and battle damage assessment for tactical operations. The study will provide significant technological support for further independent development.

Parameter Study of Some Key Structures for Cylinder Head

ZHANG Ru-hua, ZUO Zheng-xing, CAO Li-ya, LIAO Ri-dong

2004, 13(2): 183-186.

[Abstract](263) [PDF 175KB](20)

Abstract:
Using the method of the parameter study, some important dimensions of the cylinder head of an internal-combustion engine are analyzed. Under the mechanical load, the variational rules of the von Mises maximum stress on cylinder head are obtained, which are influenced by the thickness of the floor plate, head plate, jobbing sheet, standing partition board, and side plate of inlet port and exhaust port. A hypothesis is verified that there is an ideal matching point among those above-mentioned main parameters. The quantificational proportion relations, between these key structural parameters and von Mises maximum stress of cylinder head, can provide a good help for the cylinder head's structural design.

Study on Adaptive Control with Neural Network Compensation

SHAN Jian-feng, HUANG Zhong-hua, CUI Zhan-zhong

2004, 13(2): 187-189.

[Abstract](277) [PDF 122KB](27)

Abstract:
A scheme of adaptive control based on a recurrent neural network with a neural network compensation is presented for a class of nonlinear systems with a nonlinear prefix. The recurrent neural network is used to identify the unknown nonlinear part and compensate the difference between the real output and the identified model output. The identified model of the controlled object consists of a linear model and the neural network. The generalized minimum variance control method is used to identify parameters, which can deal with the problem of adaptive control of systems with unknown nonlinear part, which can not be controlled by traditional methods. Simulation results show that this algorithm has higher precision, faster convergent speed.

Formation Feedback Applied to Behavior-Based Approach to Formation Keeping

SU Zhi-bao, LU Ji-lian

2004, 13(2): 190-193.

[Abstract](185) [PDF 158KB](17)

Abstract:
Approaches to the study of formation keeping for multiple mobile robots are analyzed and a behavior-based robot model is built in this paper. And, a kind of coordination architecture is presented, which is similar to the infantry squad organization and is used to realize multiple mobile robots to keep formations. Simulations verify the validity of the approach to keep formation, which combines the behavior-based method and formation feedback. The effects of formation feedback on the performance of the system are analyzed.

Research on Maintenance Information Management System for Distributed Manufacture System

ZHANG Zhi-jing, DAI Lin, TAO Li-yan, ZHOU Juan

2004, 13(2): 194-196.

[Abstract](179) [PDF 117KB](20)

Abstract:
An architecture and design of a maintenance information management system for distributed manufacture system is presented in this paper, and its related key technologies are studied and implemented also. A frame of the maintenance information management system oriented human-machine monitoring is designed, and using object-oriented method, a general maintenance information management system based on SQL server engineering database and adopted client/server/database three-layer mode can be established. Then, discussions on control technologies of maintenance information management system and remote distributed diagnostics and maintenance system are emphasized. The system is not only able to identify and diagnose faults of distributed manufacture system quickly, improve system stability, but also has intelligent maintenance functions.

Inertia Matching During Dynamic Simulation of Vehicle Drive System on Test Bench

SONG Qiang, SUN Feng-chun, ZHENG Mu-qiao, GU Jin-chao

2004, 13(2): 197-201.

[Abstract](293) [PDF 190KB](32)

Abstract:
Framework and basic parameters of a test bench for motor drive system of electric vehicle (EV) are illuminated. Two kinds of electric drive models, one was for the electric vehicle drived on real road, the other was for that on test bench, are put forward. Then, dynamic analysis of these models is made in detail. Inertia matching method of the test bench is researched and some useful formulas and graphs are brought forward. The experiment of an electric bus is introduced in order to explain the usage of this inertia matching method.

Strain Measurement for Hollow Projectiles During Its Penetration of Concrete Targets

WANG Lin, WANG Lu, LI Shu-kui

2004, 13(2): 202-205.

[Abstract](256) [PDF 249KB](20)

Abstract:
Gives a new technique to measure the dynamic deformation behavior and strain development of a hollow steel projectile during its penetration of concrete targets. Direct strain measurement was performed by applying strain gages attached to the inner walls of the hollow projectile, linked with on-board testing and storage recorder. This on-board test-record system is easy to operate, cost-effective and can provide reasonable, accurate and detailed information. Obverse ballistic experiments were carried out on ogival-nose hollow projectiles normally impacting concrete targets at velocities from 150 m/s to 300 m/s. The deformation process of projectiles was measured, recorded and played back. Profiles of voltage-time relationship were successively obtained and transfered to strain-time relationship with the aid of calibration tables. It was found that projectiles go through a series of compression and tension deformations intermittently. Relationships between strain development and projectile deformation process were discussed.

Synthesis of Amino Acid Derived β-Cyclodextrins Used in Chiral Separation by Capillary Electrophoresis

DAI Rong-ji, TONG Bin, WEI Zheng, GU Jun-ling, DENG Yu-lin, LI Ming-yu, FU Ruo-nong

2004, 13(2): 206-209.

[Abstract](195) [PDF 148KB](21)

Abstract:
Six new kinds of amino acid derived β-cyclodextrins were synthesized to improve their water solubility and chiral separation properties. They are heptakis{2,6-di-O-[3-L-（1-isopropyl carboxyl methyl amino）-2-（hydroxy） propyl]}-β-cyclodextrin （i.e. L-Val-β-CD）, heptakis{2,6-di-O-[3-L-（1-benzyl carboxyl methyl amino）-2-hydroxy propyl]}-β-cyclodextrin （i.e. L-Phe-β-CD）, heptakis{2,6-di-O-[3-（D, L-1-benzyl carboxyl methyl amino）-2-hydroxy propyl]}-β-cyclodextrin （i.e. D,L-Phe-β-CD）, heptakis{2,6-di-O-[3-（L-1-hydroxymethyl carboxyl methyl amino）-2-hydroxy propyl]}-β-cyclodextrin （i.e. L-Ser-β-CD）, heptakis{2,6-di-O-[3-（L-1-carboxylmethyl carboxyl methyl amino）- 2-hydroxy propyl]}-β-cyclodextrin （i.e. L-Asp-β-CD）, heptakis{2,6-di-O-[3-（L-2-carboxyl tetramethylene amino）-2-hydroxy propyl]}-β-cyclodextrin （i.e. L-Pro-β-CD）. Their chemical structures were certified using FTIR and （）¹H NMR. Except for L-Phe-β-CD and D,L-Phe-β-CD, that are in soluble in water, the other amino acid derived β-CDs all have good water solubility. D,L-tyrosine and promethazine were baselinely separated by L-Val-β-CD in capillary electrophoresis.

Human Capital Investment and an Analysis of Its Progressive Profit

ZHANG De-ping, SUN Cheng

2004, 13(2): 210-214.

[Abstract](148) [PDF 171KB](18)

Abstract:
Skilled labor force cultivated through putting in funds and time in their education are undoubtedly essential in the operation of sophisticated machines in production, but it is so also in the creation of new ideas and methods in production and other economic activities, and ultimately in the promotion of the progressive increase of material capital. Thus strengthening the investment of human capital and enriching the stock of human capital is of primary importance, especially for China, in the 21st century.

Evaluation and Control of Cyclic Variation in Spark Ignited Engines by a Thermodynamic Model

JI Chang-wei, ZHANG Hong-guang

2004, 13(2): 215-219.

[Abstract](260) [PDF 196KB](22)

Abstract:
An evaluation method of engine cyclic variation is proposed based on fuzzy mathematics concept. The degree of engine cyclic variation is divided into 4 levels: stable, slight variation, moderate variation and serious variation based on the statistic standard deviation of residual gas temperatures within the specified simulation cycles and the function of cyclic variation is also inducted for the cyclic variation control. Because the degree of engine cyclic variation can be estimated qualitatively, the effective control means can be applied to appease the undesired cyclic variation. Simulation result shows that for a very serious cyclic variation through the proper adjustment of the spark angle and the cyclic variation will disappear.

Force Based Skill Learning for Robot Tasks in Contact Conditions

WANG Qin, MEI Zhi-qian, ZHANG Guang-li, YANG Ru-qing

2004, 13(2): 220-224.

[Abstract](242) [PDF 192KB](19)

Abstract:
To acquire human operation skill based on force sense, element contact form (ECF) is proposed to describe contact condition firstly. The skill is modeled as a sequence of discrete ECFs. Since different ECF has different force distribution, a support vector machine classifier is built to identify the contact conditions according to the force signal. Finally, the robot can obtain the skill from the human demonstration.

2004 Vol. 13, No. 2