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H_∞ two-block design of servo systems

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Journal of Harbin Institute of Technology(New Series) 2002年第2期9卷 142-144页

作者：王广雄王新生 dept. of control eng. Harbin Inst. of Technol. Harbin 150001 China

The usual mixed sensitivity H ∞ design is not suitable for servo design, because there exist pole/zero cancellations and the resulting control law will include a pure differentiation factor. This paper presents an alternative design, i.e. the PS/T two block design. It is proved that in the PS/T problem there is no cancellation of the plant poles by the controller. The PS/T problem can take full advantage of the two block design approach: simplicity and intuition. And the use of PS in design is more practical for it represents the system’s disturbance rejection performance. The PS/T two block design details are discussed and illustrated by an example. The results of this paper can also be used for MIMO systems.

关键词： H∞ design pole/zero cancellation PS/T problem servo system

Robot inverse kinematics based on FCM and fuzzy-neural network

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Journal of Harbin Institute of Technology(New Series) 2001年第2期8卷 184-187页

作者：王强麻亮强文义傅佩琛 dept. of control eng. Harbin Inst. of Technol. Harbin 150001 China

Presents a fast and effective method proposed by combining the fuzzy C means (FCM) and the fuzzy neural network for solving robot inverse kinematics, and its successful application to the robot inverse kinematics and concludes from simulation results that this new method not only has high efficiency and accuracy, but also good generalization, and it also overcomes the "dimension disaster" of fuzzy set in a fuzzy neural network fairly well.

关键词： fuzzy neural network fuzzy C means analysis robot inverse kinematics

A Direct Compensative Robust Optimal control (DCROC) Law for Ship Straight-line Track-keeping

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Journal of Shanghai Jiaotong university(Science) 2007年第3期12卷 364-369页

作者：李文魁田蔚风周岗陈永冰周永余 dept. of Instrument Science & eng. Shanghai Jiaotong Univ. School of Electrical and Information eng. Navy Eng. Univ.

A linear quadratic optimal direct track-keeping control law was proposed based on first-order Nomoto nominal model. Furthermore, based on Lyapunov stabilized theory, considering parametric uncertainty from variations of ship speed and disturbances uncertain from wind, wave and sea current, a direct compensative robust optimal control (DCROC) law was developed. It can guarantee closed-loop system globally and uniformly converge to a remained set. High accuracy and robustness were achieved. By introducing some nonlinear blocks, closed-loop system achieves global and uniform asymptotical stableness. Numerical simulations on a Mariner Class ship are presented to validate the control law.

关键词： ship track-keeping direct compensative robust optimal control (DCROC) Lyapunov stability

Allelopathic effect of Acorus tatarinowii upon algae

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Journal of Environmental Sciences 2001年第4期13卷 481-484页

作者： He, C.-q. Wang, C.-k. dept. of Environmental Science/eng. Shanghai University Shanghai 200072 China

Besides competing with algae for light and mineral nutrients (i. e. N, P, etc.), the root system of Acorus tatarinowii excretes some chemical substances, which injure and eliminate alga cells, to inhibit the growth of the algae. When the algae cells were treated in 'A. tatarinowii water', some of the chlorophyll a were destroyed and the photosynthetic rate of algae decreased markedly and the ability of alga cells to deoxidize triphenyltetrazolium chloride (TTC) reduced greatly. Then alga cells turned from bright red to bluish green under fluorescence microscope. These showed that the allelopathic effects of A. tatarinowii on algae were obvious and planting A. tatarinowii can control some green algae. The experiment on the extractions of the secretions of the root system showed that the inhibitory effect had a concentration effect. If the concentration of the root secretion was below 30 μl/disc, the inhibitory rate was negative; if it was over 45 μl/disc, the inhibitory rate was positive. This proved that the influence of the root secretion on the same acceptor was a kind of concentration effect. When the concentration of the root secretion was low, it promoted the growth of algae; when the concentration reached a definite threshold value, it restrained the growth of algae. In present case, the threshold value was between 30 μl/disc and 45 μl/disc.

关键词： Algae Cells Chlorophyll Concentration (process) Deoxidants Photosynthesis

A modeling method of microburst based on multiple vortex ring

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Journal of Harbin Institute of Technology(New Series) 2012年第6期19卷 111-114页

作者：林连雷闫芳 dept. of automatic Test and control Harbin Institute of Technology

Microburst is a special kind of low-level wind shear, which may do great damage to aircrafts. Modelling of a microburst is significant for flight simulations. In this paper we adopt multiple vortex ring principle to model microburst and propose a new parameter selection method of multiple vortex ring model. We treat the parameters selection as an optimization problem, and introduce the differential evolution algorithm into it. A nested differential evolution algorithm is proposed to complete the two optimization process, objective optimization and intermediate optimization. The simulation results show that this method can flexibly generate microburst with any maximum wind velocity.

关键词： microburst multiple vortex ring parameter selection nested differential evolution

Center of rotation estimation for rocket nozzle by infrared reflective makers and image sequences

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Journal of Harbin Institute of Technology(New Series) 2011年第2期18卷 56-60页

作者：张灵飞陈刚叶东车仁生 dept. of automatic Measurement and control Harbin Institute of Technology

The determination of an accurate center of rotation of rocket motor nozzle or other object to be measured is of great interest across a wide range of applications,such as rocket,missile,robotics,industry,spaceflight,aviation and human motion analysis fields,particularly for clinical gait analysis.A new approach was proposed to estimate the moving objects' instantaneous center of rotation and other motion *** new method assumes that the two segment of object to be measured are rigid body which rotates around a center of rotation between each other *** center of rotation varies with time in the global coordinate system but is fixed in the local coordinate system attached to each *** models of rocket motor nozzle and its movement were *** arbitrary moving object's corresponding to motion equations were deduced,and the least square closed-form solutions of the object's motion parameters were figured *** is assumed that the two high speed CCD cameras mounted on the 750 nm infrared(IR) filter are synchronized and calibrated in *** virtual simulation experiment using 3D coordinates of markers was conducted by synchronized stereo image sequences based on 6-DOF motion platform and the experimental results prove the feasibility of our *** test results show that the precision of x,y,z component on center of rotation is up to 0.14 mm,0.13 mm,0.15 mm.

关键词： rocket motor nozzle center of rotation stereo vision image sequence IR reflective marker high speed CCD camera

Identification of coefficients in platform drift error model

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Journal of Harbin Institute of Technology(New Series) 2002年第3期9卷 225-228页

作者：邓正隆徐松艳付振宪 dept. of control Sci. and eng. Harbin Inst. of Technol. Harbin 150001 China

The identification of the coefficients in the drift error model of a floated gyro inertial navigation platform was investigated by following the principle of the inertial navigation platform and using gyro and accelerometer output models, and a complete platform drift error model was established, with parameters as state variables, thereby establishing the system state equation and observation equation. Since these two equations are both nonlinear, the Extended Kalman Filter (EKF) was adopted. Then the problem of parameter identification was converted into a problem of state estimation. During the simulation, multi position testing schemes were designed to motivated the parameters by gravity acceleration. Using these schemes, twenty four error coefficients of three gyros and six error coefficients of three accelerometers were identified, which showed the feasibility of this method.

关键词： drift error Extended Kalman Filter parameter identification

Theoretical Studies on the SAW Properties of LGS at High-Temperature in Optimal Cuts

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Journal of Materials Science & Technology 2004年第5期20卷 512-516页

作者： Xiaojun JI, Tao HAN, Wenkang SHI and Guowei ZHANGDepartment of Instrumentation eng.neering, Shanghai Jiao Tong University, Shanghai 200030, China dept. of Instrumentation eng. Shanghai Jiaotong Univ. Shanghai 200030 China

Surface acoustic wave (SAW) devices play a significant role in signal processing, frequency control and sensing applications. In general, they cannot operate at elevated temperature. The new crystal of langasite provides possibility for surface acoustic wave devices applied at high temperature. This paper studies the SAW properties of single and doubly rotated cuts of LGS at high temperature. The calculated SAW properties of LGS are analyzed in space with aid of contour plots, and two promising SAW orientation regions at high temperature are presented. For some typical cuts and propagating directions within the two optimal regions, their SAW characteristics vs temperature are discussed. Based on the experimental evidence in some literatures, the reliability of calculated results is verified.

关键词： High-temperature Surface acoustic wave Langasite Optimal cuts

Buffer Overflow Detection on Binary Code

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Journal of Shanghai Jiaotong university(Science) 2006年第2期11卷 224-229页

作者：郑燕飞李晖陈克非 School of Information Security eng. dept. of Computer Science and eng. Shanghai Jiaotong Univ. Shanghai 200030 China

Most solutions for detecting buffer overflow are based on source code. But the requirement tor source code is not always practical especially for business software. A new approach was presented to detect statically the potential buffer overflow vulnerabilities in the binary code of software. The binary code was translated into assembly code without the lose of the information of string operation functions. The feature code abstract graph was constructed to generate more accurate constraint statements, and analyze the assembly code using the method of integer range constraint. After getting the elementary report on suspicious code where buffer overflows possibly happen, the control flow sensitive analysis using program dependence graph was done to decrease the rate of false positive. A prototype was implemented which demonstrates the feasibility and efficiency of the new approach.

关键词： binary code buffer overflow integer range constraint feature abstract graph