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RISS 인기검색어
- 검색키워드
- 저자 : Suyang Li (검색결과 5 건)
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Accuracy modeling, analysis and radical error distribution of 3-RPR planar parallel mechanism
Jian Ding,Changlong Ye,Suyang Yu,Jianguang Li,Jinguo Liu,Guangbo Hao 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.11
Output accuracy performance is directly determined by geometric errors and working poses of a mechanism. Accuracy sensitivity as geometric error transmission coefficient, closely relates to pose configuration and geometric parameters. This research focuses on accuracy of a 3-RPR planar parallel mechanism: firstly, established 3 models in an analytic form, to describe relationship between output errors and geometric ones, then they are mutually verified statistically. Secondly, the anisotropy and periodic fluctuation of position errors, independently contributed by each category of geometric errors, are illustrated; and mirror symmetric trajectories and poses generating output errors with mirror symmetry, are also revealed by numerical simulation. Finally, the radical accuracy model in an analytic form, was established through variance and covariance analysis on output errors. We concluded that the radical error of the movable platform in central symmetric poses, follows Rayleigh distribution pattern. Through statistical comparison with Monte Carlo simulation, the radical error model was demonstrated, that provided a reference for accuracy design for other planar parallel mechanism.
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High-Speed Milling of Hardened Mold Steel P20 with Minimum Quantity Lubrication
Shixiong Wu,Hongchang Liao,Suyang Li,Jundong Bi,Zhiyang Li 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.5
Strong thermal–mechanical coupling and rapid tool failure easily occur in the milling process of hardened steel with solid end mills. This work investigates the effectiveness of minimum quantity lubrication (MQL) during high-speed milling of hardened mold steel. Three kinds of spraying modes were designed in the experiment. They are namely the spraying ways to the flank face (MQL-F), to the rake face (MQL-R) and to the rake and flank faces (MQL-FR). The cutting forces, tool wear, and chips when using the MQL modes and compressed air cooling mode (CAIR-F) were compared, and the wear mechanism and lubrication mechanism were further analyzed. The results showed that the tool wear values and milling forces of several MQL modes were significantly lower than those with CAIR-F. The milling force and tool wear values were successively reduced using MQL-R, MQL-F, and MQL-FR, with better lubrication of the rake face resulting in a smaller curvature radius for the chip. Abrasion wear, adhesion/attrition wear, and flaking/chipping were the main wear mechanisms. The MQL-FR method was the optimal method of the MQL modes. It could effectively reduce the cutting contact stress and unit cutting energy, and obviously reduced wear phenomena such as adhesion and chipping.
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Lei Wang,Chuang Jiang,Tao Wei,Nan Li,Shenshen Chi,Jianfeng Zha,Suyang Fang 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.1
The data of surface movement observation points could be used to obtain the synthetic angles of draw and critical deformation of surface movement basin in the mining area with unconsolidated thick layers. However, they couldn’t be used to get the angles of draw and critical deformation of unconsolidated layers and rock layers, which are called angular parameters of surface movement basin and can be used to describe the outermost boundary and the dangerous boundary. Therefore, the paper presented an estimation method of angular parameters of surface moving basin based on least squares of Huber selecting weight iteration (LSHSWI). The method firstly classified the surface movement observation points with similar geological and mining conditions as the same kinds. Then, the synthetic angles of critical deformation and draw obtained by the observation points were taken as observation values, and angular parameters of surface movement basin were taken as unknown parameters.According to the geometric relationship between the synthetic angles and the angular parameters, the observation equation was established. Finally, the parameters estimation method based on LSHSWI was constructed with consideration of errors in the synthetic angles of draw and critical deformation. The simulation experiments show that the LSHSWI estimation method of angular parameters of surface movement basin has a strong anti-interference ability to errors of observation values. The engineering application shows that the parameter estimation method based on LSHSWI is scientific and practical.
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Fuzzy adaptive PID control method for multi-mecanum-wheeled mobile robot
Guoqiang Cao,Xinyu Zhao,Changlong Ye,Suyang Yu,Bangyu Li,Chunying Jiang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.4
Mecanum-wheeled mobile robots are widely used because they can easily realize omnidirectional movement and have flexible movement characteristics. However, existing mecanum-wheeled robots generally have problems of low movement accuracy and poor stability. Structural optimization method can improve the movement accuracy and stability of mecanum-wheeled robots, but it cannot solve the problem fundamentally. In this study, the method of geometric modeling is applied to deduce the parameters kinematic error e, slip factor μ, and overturning angle λ, all of which have an effect on the movement accuracy and stability of the robot. Combined with the advantages of PID and fuzzy control, a fuzzy adaptive PID control method is proposed. The experimental prototype of the eight-mecanum-wheeled omnidirectional mobile robot is built to carry out the trajectory tracking control experiment, and the superiority in the fuzzy adaptive PID control method is verified.
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Wind tunnel tests on flow fields of full-scale railway wind barriers
Su, Yang,Xiang, Huoyue,Fang, Chen,Wang, Lei,Li, Yongle Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.24 No.2
The present study provides a deeper understanding of the flow fields of a full-scale railway wind barriers by means of a wind tunnel test. First, the drag forces of the three wind barriers were measured using a force sensor, and the drag force coefficients were compared with a similar scale model. On this basis, the mean wind velocity and turbulence upwind and downwind of the wind barriers were measured. The effects of pore size and opening forms of the wind barrier were discussed. The results show that the test of the scaled wind barrier model may be unsafe, and it is suitable to adopt the full-scale wind barrier model. The pore size and the opening forms of wind barriers have a slight influence on the flow fields upwind of the wind barrier but have some influences on the flow fields and power spectra downwind of the wind barrier. The smaller pore size generates a lower turbulence density and value of the power spectrum near the wind barrier, and the porous wind barriers clearly provide better shelter than the bar-type wind barriers.
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