Papers by Author: Ya Fei Lu

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Authors: Ya Fei Lu, Da Peng Fan, De Jun Sheng, Zhi Yong Zhang
Abstract: A brief overview of previously built Electro-Optical Tracking system reveals a trend toward smaller, more agile systems. Steel cable drive technology is an alternative to gearbox, belt and pulleys, chains and sprocket and other currently available transmission for several significant advantages, which includes backlash free, high stiffness, high efficiency, no lubrication etc.. As a new type of drive form, there were several key tradeoffs for the cable drive application, which will be developed and subjected in detail in this paper. Firstly Transmission principle and properties of cable drive is studied. Secondly, related design considerations of cable drive will be implemented and researched in detail, including the cable selection and capstan design, cable-groove matching strategy and cable tensioning design. Finally, actual application example of precise steel cable drive is presented for an Electro-Optical tracking gimbals, and performances tested validate the significant advantages of precise cable drive technology.
Authors: Xiao Yao Zhou, Ya Fei Lu, Zhi Yong Zhang, Da Peng Fan
Abstract: A novel method in the solution of the pointing problem for electro-optical pointing system (EOPS) is presented in this paper. Firstly, the error sources are analyzed in detail. And then, a linear model whose parameters have definitely physical meaning is developed to improve pointing accuracy. Extensive experiments have been carried out and the results show that the system errors can be eliminated by the model effectively and the pointing accuracy of the azimuth and elevation axes have been improved from 0.4541º and 0.2959º to 0.038º and 0.031º respectively.
Authors: Qing Kun Zhou, Ya Fei Lu, Da Peng Fan, Zhi Yong Zhang, Lian Chao Zhang
Abstract: A novel compliant linear buffer mechanism (CLBM) is designed for impact isolation. In view of the incompatible relationship between frequency characteristic and parasitic error of compliant linear mechanism, the mixed compliant linear mechanism(MCLM) is proposed by combining the Lumped Compliant Mechanism(LCM) and the Distributed Compliant Mechanism(DCM).The topology matrices for four kinds of parallelogram linear compliant mechanisms are built through the method of type synthesis. The characteristic polynominal (CP) for the compliant mechanism matrices[CM] are calculated for the isomorphism detection of compliant mechanism. The finite element analysis (FEA) model of these four kinds of linear compliant mechanism is built to complete numerical analysis on the structure frequency and parasitic error with different sizes, and the relationship between the frequency characteristic and parasitic error of the compliant linear mechanism is found out. MatlabTM software is used to obtain the functional formulas by the method of polynomial curve fitting (PCF) for The FEA results show that the structure configuration of MCLM can achieve a higher structure frequency and a greater kinetic precision over the pure LCM and DCM at the same time, and also indicates that the analysis method of frequency characteristic and parasitic error for compliant mechanism is efficient and should be effective on the structure optimization of the novel CLBM.
Authors: Ya Fei Lu, Xiao Yao Zhou, Da Peng Fan, Zhi Yong Zhang
Abstract: Butterfly pivot is a large-travel rotational flexure pivot, which can provide elastic support for the rotational shaft in several ten degrees. Rotational precision is of great important for its application. Because of the complex structure, rotational precision is always taken with Finite Element Method (FEM), which is not suitable for design and optimize parametrically. The structure property of the butterfly pivot is analyzed before the precision analysis. Four-Blade Isosceles-Trapezoid Element is present as the basic structure unit of the Butterfly Pivot. And then, Rotational precision of the Four-blade Isosceles-Trapezoid unit is calculated and analyzed. The Self-Compensation performance of the butterfly Pivot is also studied. Work in this thesis can validate the high rotational precision of the butterfly pivot.
Authors: Mo Hei, Qing Kun Zhou, Ya Fei Lu, Da Peng Fan
Abstract: In order to reduce the effect of carrier disturbance on the stability of line of sight (LOS) of the optical-electro stabilization system (OESS), a stabilization accuracy model of stabilization loop is built, and the main factors affecting the stabilization accuracy of stabilization loop in OESS are analyzed. Based on the on-line semi-physical simulation theory, a dSPACE measurement system of the LOS stabilization accuracy is designed to measure the LOS stabilization accuracy of the OESS, and the controller of stabilization loop is designed on the basis of the measurement data on-line conveniently. Experimental results show that the stabilization accuracy of the OESS with this method is 0.24mrad which is met the requirement. The novel method of stabilization accuracy measurement and controller on-line debugging for OESS can achieve higher stabilization accuracy and a greater efficiency over the classic method, and also indicates that this novel method is efficient and should be effective on further stabilization accuracy research of OESS.
Authors: Ya Fei Lu, Qing Kun Zhou, De Jun Sheng, Da Peng Fan, Zhi Yong Zhang
Abstract: Butterfly pivot is a large-travel rotational flexure pivot, which can provide elastic support for the rotational shaft in several ten degrees. Because of the complex structure, stiffness calculation of butterfly pivot is always completed by the method of Finite Element Analysis (FEA), which is not suitable for parameter design and optimization. The serial structure of four-blade isosceles-trapezoid (FBIT)is proposed to simplified the complex structure of the butterfly pivot. The FBIT is analyzed and the theoretical formula of stiffness calculation for rotation stiffness is derived in detail based on the essential theory of Mechanics of Materials. Design and optimization of rotation stiffness for each element can be achieved easily with the obtained the theoretical formula of rotation stiffness. The total rotation stiffness of the whole butterfly pivot is calculated and the rotation stiffness comparison between using the theoretical method and by the method of FEA is performed. The error between the theoretical rotation stiffness and the result of the FEA is less than 10%. It is acceptable and without any influence on the validity of the work and concept presented in this paper.
Authors: Ya Fei Lu, Mo Hei, Zhi Yong Zhang, Da Peng Fan
Abstract: Precise cable drive has been developed as an alternative transmission element to gearbox, belt and pulleys, chains and sprocket in Electro-Optical Tracking system. Precise cable drive has several significant advantages including backlash free, high stiffness, high efficiency, no lubrication etc. This paper develops analytical methods to predict the transverse oscillation frequency of precise cable drive to enable designers to better assess dynamic performance in the design study phase. Theoretical formulation of transverse oscillation equation for precise cable drive is carried out based on Hamiltons principle taking into account flexural rigidity of cable. Furthermore, the transverse oscillation frequency is obtained from the transverse oscillation equation assuming small and linear vibration. Parametric studies are conducted to evaluate the relationship between the oscillation properties and cable drive parameters.
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