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2004 Vol. 30, No. 01

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Wind tunnel experimental study of aerodynamic interactions between a rotor and a body of a co-axial helicopter
Deng Yanmin, Hu Jizhong
2004, 30(01): 1-4.
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The results of rotors/fuselage aerodynamic interactions for the coaxial helicopter in hovering and forward flight were presented according wind-tunnel experiment. The presence of the rotor wake creates a significant down load on the fuselage which decreases with increasing advance ratio. The interactions above decreased in forward flight, but yaw moment was generated by fuselage; The interaction of coaxial rotors to fuselage changes when the tail plane area, and lower rotor pitch or advance ratio was changed. The interaction of fuselage to coaxial rotors is different from that of single rotor helicopter, such as: in hovering state, the coaxial helicopter fuselage has no obvious effect on rotors, the fuselage generates beneficial interaction to coaxial rotors when in forward flight and the interaction decreases as the advance ratio increases.
Theoretical investigation of vibration attenuation mechanism of a adaptive squeeze film damper
Ma Yanhong, Hong Jie, Zhao Fuan
2004, 30(01): 5-8.
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Vibration attenuation mechanism of an adaptive squeeze film damper with metal rubber outer-ring(ASFD/MRR) was investigated. Based on static strength analysis and motional analysis of an ASFD/MRR and an axes-s neck of rotor, Reynold equations were deduced from Nevier-Stockes equation and liquid continuous equation,and pressure field of squeeze film was solved. Comparing vibration attenuation mechanism of ASFD/MRR with a squeeze film damper(SFD), the result indicates that SFD is a special form of ASFD/MRR. ASFD/MRR can markedly restrain the occurrence of nonlinear vibration phenomenon such as bistable characteristic and it can be suitable for wider range of unbalance level.
Method for acquiring characteristic points in the calibration of line structure-light sensor
Xu Yuan, Zhang Guangjun, Wei Zhenzhong
2004, 30(01): 9-13.
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Based on the cross-ratio invariance theorem, a new method for acquiring characteristic points in the calibration of line structure-light sensor was proposed. A larger number of high precision characteristic points were easily acquired using this method and the designed calibration target. The problem that it is difficult to acquire a lot of high precision characteristic points was resolved and the calibration precision was improved. The simulation results verify the feasibility of this method.
Research and applications of radial basis process neural networks
Xu Shaohua, He Xingui
2004, 30(01): 14-17.
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A radial basis process neural networks model was proposed, which is a kind of three-layer forward structure constituted of input layer, radial basis function hidden layer and output layer. The transformation from input layer to hidden layer is nonlinear and that from hidden layer to output layer is linear. The neurons of hidden layer perform the pattern matching of process input information and aggregation operation of time and respond to the input patterns. Through inducting function orthogonal basis into input space, input function can be expanded under the orthogonal basis and aggregation operation process can be simplified by using the orthogonality of basis function. The corresponding learning algorithms were given and the effectiveness of this method was proved by rotation machinery fault diagnoses.
Multiple fading Kalman filter based on hypothesis testing
Zhuang Chaowen, Fu Li, Fan Yuezu
2004, 30(01): 18-22.
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A new multiple fading Kalman filtering algorithm was proposed based on hypothesis testing. The algorithm on-line modifies the noise covariance of the Kalman filter by the fading matrix using chi-square testing method so as to improve the accuracy and convergency of the Kalman filter when there exist errors or when the plant was affected by unmeasurable external disturbances. The proposed algorithm was applied to a vehicle global positioning system/inerial navigation system/integrated navigation system(GPS/INS) and behaved satisfactorily.
Kinematics analysis of parallel mechanisms 3PSS
Guo Weidong, Han Xianguo, Chen Wuyi
2004, 30(01): 23-26.
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The kinematic characteristics of 3PSS parallel mechanism was thoroughly analyzed. It was proved in theory that the motion of the movable platform is translation, and this kinematic characteristics of the mechanism was validated by the virtue prototype technology using the software of the dynamic analysis of mechanism systems ADAMS. The workspace of the movable platform of the mechanism was analyzed and the mathematic express of the workspace was given on the base of the theoretical analysis. The 3D configuration of the workspace was drawn up. This will establish the foundation for the locus plan of the mechanism.
Implementation of the comprehensive situation display sub-system in the distributed virtual battlefield
Li Zhengyu, Shen Xukun
2004, 30(01): 27-30.
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In the distributed virtual battlefield environment, the comprehensive situation which displays sub-system is a major part of the management system. It takes charge of real-time displaying the state of all the entities in the virtual battlefield. To show the entities' information, the requirements of users were analyzed firstly, and then the architecture was designed. Based on high level architecture (HLA), a viable method was proposed and the implementation was fulfilled at last. The experiments show that the sub-system meets the requirement completely.
Dynamic characteristic analysis of rotating composite shell
Shi Yajie, Hong Jie, Wu Wei
2004, 30(01): 31-35.
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In the dynamic analysis of drum-type composite rotor, not only the dynamic behavior of rotor system but also the vibration characteristic of drum-type composite rotor should be studied. By reprogramming the finite element analysis software MSC/NASTRAN using DMAP program, the dynamic characteristic of rotating laminated composite shell and the influences of coriolis, centrifugal and transverse shearing forces on nature frequencies were investigated andcompared with experimental results. It indicated that coriolis, centrifugal and transverse shearing forces have great influences on the vibration modes of rotating shell. The results also indicated that there exist forward and backward traveling waves even in the rotating coordinate system because of the effects coriolis force.
Analysis of elevation error for radar seeker tracking low altitude target
Dang Qun, Lü Shanwei, Dong Shengbo
2004, 30(01): 36-39.
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The elevation error of seeker tracking low altitude target was affected by multipath propagation. The traditional ‘little plane’,which calculates diffuse reflection coefficients, was used in uniform terrain meshing. But uniformterrain meshing has a high error rate in big grazing angle. An improved method which doesn't divide terrain uniformly and analyses effects of four paths propagation was proposed. The method of estimation elevation estimation commonly is open-loop track. A close-loop tracking method and improved method of‘little plane’which calculates diffuse reflection on ground/sea were presented. When the seeker track low altitude target, the elevation error was simulated better and calculation time was greatly reduced.
Design and analysis of an anthropomorphic finger joint for robotic dexterous hand
Liu Bo, Guo Weidong, Zhang Yuru
2004, 30(01): 40-42.
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One of the difficult problems in designing a robotic hand is to achieve the same size of the human counterpart with all the actuators integrated into the hand. The design of an anthropomorphic joint which provides pitch and yaw motions of the finger relative to the palm was described. The joint consists of two intersecting axes and five bevel gears, which allows the motors to be placed in the palm to achieve a compact structure. The kinematic model of the joint was developed and verified by a virtual prototype. The application of the joint can improve the dynamic performance and simplify the mechanical structure of the robotic dexterous hand.
Effect of operational parameter on the heat transfer in a heat receiver
Cui Haiting, Yuan Xiugan, Xing Yuming
2004, 30(01): 43-46.
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It is possible to solve some problems using the three different multiple phase change material to replace single kind of high-temperature phase change material in heat receiver for NASA 2 kW solar dynamic power system. The heat receiver model was established. The corresponding numerical methods were described. Tube maximum temperature, gas exit temperature and liquid phase change material fractions were calculated based on working parameter such as gas inlet temperature, receiver heat input and gas mass flow rate. Results indicate that parametric changes in receiver gas inlet temperature and receiver heat input effects higher sensitivity to changes in receiver gas exit temperatures. Selecting these parameter is very important to improve the heat receiver thermal performance.
Up and down method for DFR testing
Bao Rui, Zhang Jianyu, Chen Bo, Fei Binjun
2004, 30(01): 47-50.
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The up and down method to determine the detail fatigue rating (DFR) with experimentation was presented, which provides a more efficient way for DFR testing. Via numerical simulation, the half-sample maximum likelihood estimation method was proved to be effective to gain the mean value of fatigue strength. But it must be modified when used to estimate the standard deviation. The confidence degree was ensured by the least amount of specimen. At last, the expression of DFR acquired by the up and down method was given.
Study of a 3-DOF parallel manipulator dynamics based on Lagrange's equation
Bai Zhifu, Han Xianguo, Chen Wuyi
2004, 30(01): 51-54.
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Based on Lagrange's equation, the dynamic equation of a 3-DOF parallel manipulator was established and the drive force acted on the mechanism was given. Computer simulation was performed to investigate the driving forces variation when the platform moves along a circle and to study the force errors due to the model simplification, based on which, the condition for simplification was given. The relation between system parameters and drive force of the mechanism was obtained. The results provided references for detailed research on dynamic characteristics and optimal design of the parallel machine tools.
High-speed circuit design in software radio
Cui Yingwei, Zhang Xiaolin
2004, 30(01): 55-58.
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The definition of high-speed circuit design as well as the signal integrity and timing problems in this design was introduced. The usual termination methods to remove reflection in high-speed circuit design were analyzed, and the simulation result of serial termination and parallel termination were compared in details. From the view of engineering and with connection to practical application, reasonable connection topological structures were proposed, and the experiment data were also provided. Finally the timing problems in high-speed circuit design were analyzed and the conditions of timing design in source synchronous clock system were derived.
Strategy for updating the data of automatic topology discovery
Du Yushui, Zhou Gang, Ma Shilong, Dong Weiyu
2004, 30(01): 59-63.
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A strategy for updating the data obtained during the process of automatic topology discovery was presented. This strategy can be applied to the changes detected in time with the minimum cost, and several important problems which have to be faced in practice were discussed. In the end, the effectiveness of our approach in terms of correctness and speed of automatic topology discovery were demonstrated, based on an analysis of a large experimental network.
Study of dynamic responses of rotor systems to transverse forces
Shi Yajie, Lin Yun, Hong Jie
2004, 30(01): 64-69.
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The characteristics of the rotating stall and surge in axial compressors showed that it is the rotating stall that generates the force on the rotor in radial direction. A mathematic model of the force on rotor in radial direction was established to simulate the change of pressure in compressors. The complex eigenvalues and transient responses of the single-rotor system and dual-rotor system were studied using the programs which were developed in direct matrix abstraction program(DMAP) based on MSC/NASTRAN platform. Some general disciplinarians of dynamic responses of rotor systems to transverse force were found, which was helpful to how to take into account the transverse forces when designing the rotor systems of aeroengine.
Effects of stability factor on FDTD numerical calculation
Li Jun, Wu Zhenbo, Wu Zhe
2004, 30(01): 70-73.
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The function of stability factor was discussed in FDTD calculation. Modification formula of two-order Mur condition including stability factor was derived. Taking example for line source, effects of stability factor on absorbing boundary capability and numerical stability were studied. Plane wave was added to three-dimensional calculation space as soft excitation source. The variety of RCS and convergence performance with stability factor was computed. Results show that increasing temporal increment is favorable when satisfying numerical stability condition.
Application of qualitative error analysis method in the mechanical navigation system
Chen Ming, Hu Jizhong, Cao Yihua
2004, 30(01): 74-78.
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The rigid-wake mode of co-axial rotor in forward flight was set up based on analysis of infinite blade rigid-wake mode. The method of aerodynamic characteristics of co-axial rotor in forward flight was studied by given rotor geometry, distance between upper and lower rotor, advance ratio. The example of the method indicates that the theoretical and experimental results are consistent well.
Cost analysis method of requirement product
Li Fan, Deng Jia
2004, 30(01): 79-82.
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To formulate the cost of requirement product is benefical to marketing localization of the product and it can encourage the design for cost. How to evaluate the product cost in the phase of requirement design was researched and a cost analysis method of requirement product based on requirement cost features was presented. This method takes all costs in the product life cycle into account, and through the requirement cost features break-down structure (RCFBS) the extensibility of the cost category can be facilitated and the reuse of cost components can be achieved. With this method enterprises can be assisted in decision-making in order to gain the predominance in the ardent market competition.
Application of qualitative error analysis method in the mechanical navigation system
Hu Lei, Zhang Li-dan, Wang Tianmiao
2004, 30(01): 83-87.
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The qualitative error analysis of the mechanical navigation system was implemented using Taylor series expansion method after introduction of the system characters. The accuracy and effectiveness of this method were expressed by the compare results of qualitative analysis with specific experiment test of computer-assisted distal locking system of intramedullary nail . The idea of this method can be used as a reliable basis for designing and optimizing the same kind of system.
Reliability simulation for the environment controlling system of the airplane
Yuan Lifeng, Wang Jun
2004, 30(01): 88-90.
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Based on the fault model and fault tree, the data of the environment control system of the airplane made in china were analyzed. After founding the reliability simulation model using the method of the invalidation, the simulation of this system was analyzed to get the conclusion. Then Some suggestion was put forward based on the simulation conclusion.
Heat and math transfer mathematical model and numerical computation of rotary dehumidifier
Liu Zhongbao, Wang Jun
2004, 30(01): 91-94.
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The heat and mass transfer mathematical model of a rotary solid desiccant dehumidifier was presented. Some comparison were made between the scheme of using gas from the outlet dehumidified to regenerate solid adsorbent and the one without using gas from the outlet dehumidified to regenerate solid adsorbent. Some figures and laws have been got according to numerical simulation .On the given parameters of desiccant dehumidifier, the content of humid air decreases rapidly as the mass flow of regeneration air is increasing at 0~1.5 kg/(m2·s). If T2＜450 K, the content of humid air decreases rapidly when T2 is increasing. If T2＞450 K, the content of humid air decreases slowly when T2 is increasing. The results can be applied to optimize the design of rotary desiccant dehumidifier.

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