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2012 Vol. 38, No. 1

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Brushless DC motor double closed-loop control system based on variable coefficient PID
Guo Hong, Wu Haiyang, Wu Peijun
2012, 38(1): 1-5.
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A variable coefficient proportion integration differentiation(PID)algorithm used in the position loop was proposed and analyzed in the control system of electrical dual-redundancy brushless DC torque motor used in the direct drive valve. The steady-state error of the system was eliminated quickly by enhancing the influence of proportion regulator and integrator gradually according to the position deviation. The integration of position error was limited to ensure the system'sstability. Experimental results show that the variable coefficient PID algorithm used in the position loop can ensure the system'sstability and the accuracy of the position response, whatever the inner loop uses current loop or velocity loop. For the same step response, the step rise time of the double closed loop structure of the position and current reduced more than 32% compared with that of the double closed loop structure of the position and velocity. However, the double closed-loop structure of position/velocity loop performs strong loading appliance and strong robustness.
Method of modeling transient two-phase flow in injector
He Yongling, Ding Chuan
2012, 38(1): 6-10.
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A new method was applied in modeling and numerical simulation in transient two-phase flow inside a diesel injector for cavitation study. The simulation was started in steady flow when the needle valve was just about to be lifted and then contined to compute unsteady flow with self-made program. User define function(UDF) provided by Fluent was used in definition of boundary condition, force analysis of needle valve and computation of its speed. The initial condition was from steady flow field then every unsteady computation was decided by former flow field. This method assured numerical simulation consistent and authentic. It is possible to simulate the whole fuel injection with injector's initial condition and get statistics of pressure and phase volume fraction distribution at any time inside an injector. Simulation results are close to experiment results and it evidences that this new modeling method is valid and reliable. Cavitation commencement, expansion and disappearance are revealed during fuel injection. This modeling method provides a new way to further study two-phase flow inside diesel injection system.
Design and experiment of explosive cutting device of bail-out emergency exit
Feng Wenchun, Dang Xiaomin, Guan Huanwen, Song Wenjuan
2012, 38(1): 11-16,90.
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The technology of explosive cutting aircraft skin formed emergency exit was used in emergency evacuation of aircraft to save the time of evacuation. The feasibility of formed emergency exit through explosive cutting aircraft skin and fuselage frame in higher flight altitude was analyzed from the rapid decompression, construct distortion, construct intension and reverse impact of explosive to aircraft. Because of the exising of frame and rib, the linear shaped charge (LSC) must bend to round this construct which will reduce the cutting effects of LSC. In order to validate this phenomenon, plenty of experiment were carried out. The test result show that if the distance between the curving LSC and frame was controlled in 2 mm and 8 mm, and the distance between the curving LSC and rib was less than 2 mm, the request of cutting skin and frame can be satisfied. There is no interference between the curving LSC which round the frame and rib. The feasibility of explosive cutting aircraft skin formed emergency exit was proved by the full scale test of ground.
Analysis of aero-optical distortions based on canonical correlation analysis and proper orthogonal decomposition
Xu Dong, Liu Haowei, Duan Yue
2012, 38(1): 17-21.
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The methods of canonical correlation analysis (CCA) and proper orthogonal decomposition (POD) were used to study the 3D density field data computed by computational fluid dynamics (CFD). 2D-CCA was adopted to extract the canonical correction features between two cross sections along the spanwise, and then POD was adopted to eliminate the redundancy information between two cross sections. In this way, the features containing the domain information were extracted from the original data. The extracted feartures are then used to reconstruct the 3D density field, and the simulated corresponding aero-optical effect distortions gives the evidences that light transmission in reconstructed field is similar to the original field.
Autonomous pulsars navigation method based on ASUKF for Mars probe
Ning Xiaolin, Ma Xin, Zhang Xueliang, Wu Jinyuan
2012, 38(1): 22-27.
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Autonomous navigation using pulsars is characterized by its steady, credible performance, high navigation accuracy, which is suitable for mars probe. Because errors in photons time of arrival reduce location accuracy, a kind of pulsars navigation method based on ASUKF (augmented state unscented Kalman filter) was presented. System models using position, velocity and constant error in time of arrival as state parameters were built. The method could not only estimate and correct the constant error in photons time of arrival, but reduce the influence of random error as well. Simulations show that a estimated position error within 350m is obtained, which demonstrates this method can satisfy the requirements of Mars exploration.
Characteristic and detection of Mars dust
Sun Lilin, Qin Guotai, Zhu Guangwu
2012, 38(1): 28-32.
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Mars dust contributes to the Mars atmosphere dynamic and thermodynamic evolution process and the long-term modification of Mars albedo and surface geology.Mars dust environment is very crucial for the power system and optical sensors onboard Mars landers (or rovers).There is a need for Mars dust in situ measurement.The characteristics and main detecting solutions of Mars dust were discussed.Based upon Quartz Crystal Microbalance technology, the design of Mars dust characteristic integrated detecting system (MDCIDS) was proposed.MDCIDS includes 3 kinds of sensors.The dust accumulation sensor can measure the accumulation rate and mass of Mars dust with sensing crystal surface upward.The charging dust sensors can measure the accumulation rate of positive and negative charging dust through applying different bias voltages to crystals.And the magnetic dust sensors can measure the accumulation rate of magnetic dust with small permanent magnets behind sensing crystals.The accumulation mass range is 10-11~10-4g.MDCIDS is expected to be applied to future Mars landing exploration mission.
New north finding algorithm for strapdown compass based on FOG
Wang Yu, Cheng Xianghong, Wu Jun
2012, 38(1): 33-38.
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The ship rolling prevents a gyroscope from reliably measuring the angular velocity of the earth's rotation (Ω). Consequently,the strapdown compass system based on fiber optic gyroscopes (FOG) cannot compute the heading of the carrier based on the outputs of gyroscopes and the accelerometers. To address this issue, a new north finding algorithm was proposed. By taking the inertial frame as the reference coordinate frame, this algorithm established the transitional inertial frame and the initial-time strapdown compass body inertial frame. The direction of vector Ω was then calculated according to the projection of the accelerometer sensitive to grivity in the initial-time body inertial frame. And this in turn recovers the true north of geographic direction. The proposed north finding algorithm consists of three steps. It established the initial-time body inertial frame. Then it obtained a stable level frame via the initial-time body frame and the outputs of gyroscope and accelerometer. By projecting the output of accelerometer from the strapdown compass body frame to the initial-time body inertial frame, the direction of vector Ω was calculated by the space circle fitting method. Then the true north was recovered by projecting the vector parallel with Ω from the initial-time body inertial frame to the stable level frame. The simulation result shows that the error of azimuth can be reduced to as low as 0.23°(1σ) .
Fuzzy comprehensive evaluation of corrosion damage of aircraft structures based on fault tree
Pan Bo, Jiang Tongmin
2012, 38(1): 39-42.
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To resolve the complexity and fuzziness of influence on the corrosion damage of aircraft structures, a method based on fault tree analysis and fuzzy theory was proposed to evaluate the corrosion damage of aircraft structures in complicated environments. Fault tree of corrosion damage on aircraft structures was set up by analysis of corrosion process and mechanism, and then the evaluation set of corrosion damage was obtained. Relative importance of evaluation factors was analyzed, and weight set was got by the proportion calculation of relative importance of evaluation factors. After the evaluation grade of corrosion damage has been set up, the fuzzy mapping between evaluation set and evaluation grade was set up. The corrosion damage of service environments on aircraft structures was evaluated quantitatively by fuzzy transformation of fuzzy relation. Finally, corrosion damage evaluations of aircraft aluminum alloy structures and stainless steel structures in coastal environments were illustrated, which demonstrate that the proposed method is valid and can provide evidence for the aircraft structural design and maintenance.
Approach for degradation data analysis based on proportional failure rate model
Zhong Qianghui, Zhang Zhihua, Liang Shengjie
2012, 38(1): 43-47.
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Reliability evaluation using products' performance degradation data has become an important method which solves the problem of insufficient failure lifetime observations. On the basis of analyzing the close correlation between products' failure rate and failure critical values, the proportional failure rate mode was introduced for describing the relationship between products' life and failure critical values, and the degradation analysis model was built using the relationship between the lifetime distribution and the degradation characteristic' distribution. In the proposed approach, the physical degradation path model and the degradation characteristic's distribution were not assumed, the values of reliability at different inspection times and different failure critical values were got using products' degradation information, then the unknown parameters were estimated through distribution fitting method and reliability assessment was performed. This approach not only relaxes model assumptions, but applies to dealing with some non-balanced-structure degradation data, which makes it have better adaptability. Finally, an example was given to demonstrate the validity of this approach.
Rotation distortion of local coordinate frame in curve skeleton-driven body deformation
Wang Cheng, Dai Shuling
2012, 38(1): 48-52.
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An analysis of defects resulting by using three basic orthogonal axes method to construct a local coordinate frame in body deformation was presented. A new approach which was a position-quaternion solution was proposed to improve the defects and rotation distortions of local coordinate frame in curve skeleton-driven body deformation. It took the technique of quaternion spherical linear interpolation and B-spline quaternion interpolation to construct a local coordinate frame, adopt a position-quaternion-scale method to replace traditional transform matrix. It achieved vivid and realistic human skin and muscle deformations by binding body surface vertices to local coordinate frames. The results show that the method effectively eliminates the local coordinate system rotation distortion, fewer restrictions to apply and easy to implement.
Integrated analysis of aerothermal-aeroelastic wings in hypersonic flow
Li Guoshu, Wan Zhiqiang, Yang Chao
2012, 38(1): 53-58.
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To research the static aeroelastic problems of the hypersonic vehicles in which the thermal effects must be considered, the rapid analysis of the hypersonic vehicles from aerodynamic heating to static aeroelasticity was developed. A hierarchical solution process was used to dealing with the aerothermal-aeroelastic coupling problems. The whole flow field was divided into inviscid flow field out of the boundary layer and viscous field inside the boundary layer, and the method simulating the inviscid flow field numerically and predicting the viscous field experientially was used to compute the hypersonic aerodynamic heating and the temperature field. The stress stiffness matrix under this temperature field was developed. A hypersonic low aspect-ratio wing was researched, and the temperature field, thermal stress, thermal stiffness and static aeroelastic characteristic of the wing was computed. Therefore, the feasibility and applicability of this aerothermoelastic rapid analysis is demonstrated.
Mission reliability assessment for battle-plane based on flight profile
Liu Zhenyu, Ma Xiaobing, Hong Dongpao, Zhao Yu
2012, 38(1): 59-63.
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The mission reliability of battle-plane varied under different flight profiles. According to the characteristics of battle-plane's fault data, the flight profile conversion factor was introduced to establish the mission reliability model of battle-plane. Based on the model, the statistical inference method of failure rate for battle-plane was proposed, and the mission reliability was assessed under a given flight profile. For a scenario flight profile, a synthetic method was used to describe it as a weighted combination of typical profiles. Thus, the prediction method of mission reliability under the scenario flight profile was put forward by using the failure rates under typical profiles. The illustrative example shows that the method is reasonable and straightforward for engineering.
Modeling and verification of de-icing software safety requirement based on expanded Petri net
Li Zhen, Liu Bin, Lu Minyan, Yin Yongfeng
2012, 38(1): 64-68,105.
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As a formal method, Petri net can ensure the correct construction of system but lacks the ability of modeling complicated system and automatic verification. Firstly, the formal semantics of Petri net was expanded, the place of state and numeric were distinctively defined, the transition state of fired and inhibitory were distinctively defined, the non-precondition, unitary precondition and composite precondition were introduced, and the model was transformed into verification program to implement the safety verification according to formal definitions. And then, the effectiveness of this methodology was illustrated with an application in an aircraft de-icing system which is a typical safety-critical system. The process and result show that the expanded model and methodology enhance the ability of Petri net to model complicated software system, improve the software safety, and the automatic transform from model to codes settle the workload of rewrite corresponding code manually and the meaningless faults introduced by that when the model should be modified.
LSP to improve vibration fatigue performance of deflation valve lever
Li Qipeng, Li Yinghong, He Weifeng, Liu Hailei
2012, 38(1): 69-74.
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In order to solve the fatigue failure of the valve lever fixed in certain aeroengine, the technology of laser shock processing (LSP) on the valve lever was studied. Then, the valve levers of prototype and valve levers processed by LSP, shot peening (SP) and enlarge R were applied to vibration fatigue test. The results show that at the vibrating stress level of 317MPa, compared with the prototype, LSP, SP and enlarge R could increase the fatigue life by 424%, 289% and 36% distinguishably. The effectivity, stability and operability of LSP make it the best way to decrease fatigue failure of the valve lever at the present time. The LSP strengthening effect on valve lever is attributed to the low roughness, the high numerical compressive residual stress field about 1.4mm in depth and the grain refinement to nanocrystal accompanied with high density dislocation. The three factors above are the main reasons what LSP could prolong the fatigue life of valve lever, because that they work together could efficiently release the stress concentration at R area as well as restrain the initiation and propagation of fatigue crack.
Schedulability analysis for AFDX-based avionics systems
Zhou Tianran, Zhang Yongtao, He Feng, Xiong Huagang
2012, 38(1): 75-79.
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Avionics full duplex switched ethernet (AFDX) is designed for on-board communications in the new generation large aircraft. AFDX-based avionics systems are required to guarantee that hard real-time applications can be completed within their dead-lines. While current researches on real-time performance of AFDX only give the delay upper bound of frames,both the response-time of tasks in each processor and the delivery delay of hard real-time messages in AFDX networks were consided. The AFDX-based avionics system model was built, and the timing requirement of distributed task sequences was analyzed. Then, the worst case response time of task sequences was derived by using the holistic analysis. The proposed schedulability analysis provided a theoretical means to evaluate and optimize system real-time performance. Simulation results manifest that this analysis can give the tight upper bound for response time of task sequences.
Dynamic characteristic of vibration isolation platform of control moment gyroscopes on satellites
Zhang Yao, Huang Tingxuan, Xu Shijie
2012, 38(1): 80-85.
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An isolation scheme for control moment gyroscopes (CMGs) was put forward and used on satellite which can provide an ultra quiet environment for the optical payloads, and dynamic characteristic of the vibration isolation platform for CMGs was analyzed in detail. The theories of the vibration isolators of different parameter models and the reason of choosing certain parameters were studied. A whole-satellite dynamic model with vibration isolation platform and CMGs was constructed by Newton-Euler method. The force transfer rates of different parameter models were compared by using frequency domain method. The ameliorative degrees of vibration isolation device with the two-parameter and three-parameter model to the satellite attitude stabilization were compared by using time domain method. The simulation results show that the vibration isolation platform with two-parameter adding tuned mass damper model can attenuate the resonance amplification peak to a certain extent, and the vibration isolation platform with three-parameter model had the best performance in the three models.
Virtual view synthesis based on triangular re-projection
Zhang Chunxiao, Zhao Yan
2012, 38(1): 86-90.
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Traditional view interpolation can only synthesize the novel view along the base line. The proposed method based on triangular re-projection can iteratively divide the scene into consistent and inconsistent triangles given a few of initial matches, and implement free-viewpoint view synthesis by re-projecting these two groups of triangles in different strategies. The straight line constraint was introduced to direct the division along the line in order to reduce the discontinuity nearby the common side of two adjacent triangles. The new matching points were confirmed by the designed evaluation function in a special searching order. They were detected in the inconsistent regions for further division to produce more and more consistent regions. The color-image experiment proves that this method is effective to synthesize a photo-realistic image under wider changes in viewpoint.
Time modeling and constraint verification of large-scale device collaboration system
Rong Xiaohui, Ma Shilong, Deng Pan, Chen Feng
2012, 38(1): 91-97.
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Aiming at the characteristics of complex time attributes and difficult time constraint verification in large-scale device collaboration system, a large-scale device collaboration model containing time attributes was presented. The time attribute was composed of device operation time and status duration time. By adding the time property on operations, the modeling of device operation time was achieved, and by adding the time property on connectors, the modeling of status duration time was achieved. Based on the time model, a calculation method of time of four basic structures in large-scale device collaboration was proposed. Through structural equivalence, the basic structure was equaled as a connector. So the time properties of all nodes in device collaboration model can be calculated. And the rule of time constraint verification was given. The result of comparison and simulation experiments shows that the method is more accurate, bias of the method is lower and it can satisfy the performance requirements of the large-scale device collaboration system.
Terrain following and autonomous landing using optical flow
Liu Xiaoming, Chen Wanchun, Xing Xiaolan, Yin Xingliang
2012, 38(1): 98-105.
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An optical flow sensor, which is fabricated by our laboratory, was mounted on a unmanned aerial vehicle(UAV) to implement terrain following and autonomous landing tasks by using optical flow as feedback. The performance of the optical flow sensor was tested and the UAV model was built. Control algorithm for terrain following based on optical flow was developed and landing strategies using optical flow as feedback was proposed.Mathematical simulations and hardware-in-loop tests show optical flow information can be used in a relatively simple form to control both the flying speed and altitude at the same time to ensure the safety of flying missions for the UAV. The optical flow sensor is proved available for flight control by the hardware tests.
Resident region extraction using Gabor filter in aerial imagery
Gu Duoyu, Guo Jiang, Li Shuxiao, Chang Hongxing
2012, 38(1): 106-110,122.
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Automatic extraction of resident regions from medium and low revolution aerial images plays a crucial role in geographic information system(GIS) updating and unmanned aerial vehicle(UAV) navigation. The parameters of Gabor filter in detail were analyzed, and a fast resident region extraction algorithm based on Gabor filter was proposed. The method composed of four steps. Firstly, the texture features of input image were extracted using Gabor filter. And then the texture features were smoothed by the kernel density estimation method to get the confidence image. Subsequently, the confidence image was segmented by the basic global threshold algorithm to acquire candidate regions. Ultimately, the candidate regions were verified by the geometric structure information. The method has low computational complexity, and can run within 0.42s in average. The efficiency and accuracy of the proposed algorithm were demonstrated by the experimental results.
Robust eigenstructure assignment based on μ-analysis applied to flight control law design
Gao Bo, Yang Lingyu, Shen Gongzhang
2012, 38(1): 111-115.
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A new robust eigenstructure assignment algorithm was presented to improve the robustness of control law designed by eigenstructure assignment. This algorithm combined parametric eigenstructure assignment with μ-analysis, was based on linear fractional transformation, and then transformed robust eigenstructure assignment problem into a nonlinear constrained minimization problem including all free parameters of the system. In order to reduce the problem complexity, robust eigenstructure assignment with multivariable optimization was divided into two steps with contour graph of robustness index, considering the characteristics of flight control. This algorithm ensures the performance of nominal closed-loop system with parameter constraints, and can improve the robustness with all free parameters of the system and has the advantages of μ-analysis. The simulation results show that this algorithm can satisfy level 1 flying qualities,improve the robustness and reduce the conversation.
Syndrome-based distributed joint source-channel coding scheme
Pan Xuzhou, Liu Rongke, Wang Yan
2012, 38(1): 116-122.
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A syndrome-based error resilient scheme of distributed joint source-channel coding was addressed. Without increasing the complexity of the encoder, a new appropriate syndrome based encoder with compression and error resilient capability were designed. Secondly, a corresponding decoder was designed and the existing joint decoding algorithm was improved, introducing a new information exchange, to improve the performance of the decoder. Simulation results show that the performance of the proposed scheme is better than that of the existing syndrome-based distributed joint source-channel coding scheme in the noisy channel and the performance of the scheme is also better than that of the parity-based distributed joint source-channel coding when the signal to noise ratio (SNR) is high.
Maintenance-support model of materiel considering support equipment failure
Wang Yan, Ma Lin, Wen Jia, Kang Rui
2012, 38(1): 123-127.
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To analysis the impact of failure and logistics of support equipment bringing on the materiel support efficiency,the effect of support equipment failure resulting in maintenance tasks and the logistic process of support equipment in depots and between depots was described, a model of logistics process of support equipment in a depot was set up. New parameters such as effect rank and additive maintenance task was put forward in order to measure the impact of support equipment failure. A simulation model describing materiel support process considering the logistics of support equipment was set up in comparison with traditional simulation model. useful method was provided in carrying on logistics of support equipment and putting forward reliability and maintainability requirement.
Distributed adaptive cooperative guidance for multi-missile salvo attack
Zou Li, Kong Fane, Zhou Rui, Wu Jiang
2012, 38(1): 128-132.
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A distributed adaptive cooperative guidance law for multi-missiles with heterogeneous leader-follower was proposed to implement salvo cooperative attacks. On the basis of local communication and traditional proportional guidance law, a distributed cooperative guidance law for multiple heterogeneous missiles with leader-follower was developed using the principles of synchronization in coupled dynamic networks. The distributed cooperative guidance of the leader missile was based on the proportional navigation guidance law with constant navigation coefficient, while the distributed cooperative guidance of the follower missile was based on the proportional guidance law with adaptive variable navigation coefficient. The effectiveness of the proposed distributed adaptive cooperative guidance law was demonstrated by the simulation results of five missiles salvo attacks.
Stability analysis on scale factor of accelerometer based on fuzzy theory
Huang Xiaokai, Chen Yunxia, Zhang Shunong, Kang Rui
2012, 38(1): 133-137.
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Fuzzy theory was used to analyze the scale factor stability of accelerometer, since many affected factors of scale factor of accelerometer emerged some uncertainty nature, which can be describe by fuzzy theory. Specifically, triangular fuzzy numbers was used to derive the changing interval of magnetic flux density and thermal expansion coefficient of quartz material, which is the dominant affected factors for scale factor stability, according to the different combination of triangular fuzzy numbers results, ANSYS magnetic-structure coupling simulation was introduced to get the different accelerometer simulation output, and then obtained the scale factor fuzzy stability interval, which was applied to the analysis of scale factor stable condition in the accelerometer accelerated stability test and the conclusion was properly. The conclusion illustrate that fuzzy theory analysis of scale factor stability can provide appropriately condition in the accelerometer accelerated stability test, for neither waste the cost of the test nor inadequate for the result, the conclusion also have great significance to the improvement of accuracy level for the long-term stability of accelerometer scale factor.
Principle and application of functional dimension driving in 3D tolerance analysis
Zheng Hongyong, Zheng Guolei, Zhao Huangjin
2012, 38(1): 138-142.
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As the differences between functional dimensions and modeling parameters of the product bring limitations on the application of parameter-driven technique in tolerance analysis, a method based on functional dimension-driven technique was presented. Traditional dimensions were defined by constraints between geometric elements of the product model, and the mapping mechanism between functional dimension set and modeling parameter set was analyzed. The problem of functional dimension driven was converted to the solution of a set of non-linear equations, which was then solved by Newton's method. These methods were implemented on the UG system, and applied to analyze a selected mechanism.

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