A novel technique for calibrating crucial parameters of chassis components is proposed,which utilizes the machine vision metrology to measure 3D coordinates of the center of a component's hole for assembling in th...A novel technique for calibrating crucial parameters of chassis components is proposed,which utilizes the machine vision metrology to measure 3D coordinates of the center of a component's hole for assembling in the 3D world coordinate system.In the measurement,encoding marks with special patterns will be assembled on the chassis component associated with cross drone and staff gauge located near the chassis.The geometry and coordinates of the cross drone consist of two planes orthogonal to each other and the staff gauge is in 3D space with high precision.A few images are taken by a highresolution camera in different orientations and perspectives.The 3D coordinates of 5 key points on the encoding marks will be calculated by the machine vision technique and those of the center of the holes to be calibrated will be calculated by the deduced algorithm in this paper.Experimental results show that the algorithm and the technique can satisfy the precision requirement when the components are assembled,and the average measurement precision provided by the algorithm is 0.0174 mm.展开更多
A novel fiber Bragg grating （FBG） rain gauge is proposed in this paper to achieve high precision rainfall measurement. One core sensitive FBG, a temperature compensation FBG and a mechanical transition system constr...A novel fiber Bragg grating （FBG） rain gauge is proposed in this paper to achieve high precision rainfall measurement. One core sensitive FBG, a temperature compensation FBG and a mechanical transition system construct this novel FBG rain gauge. Sensing principle of this FBG rain gauge is explained in detail, and its theoretical calculation model is also established, which shows that the relationship between center wavelength of sensitive FBG and external rainfall has very good linearity. To verify its detection performance, the calibration experiment on one prototype of this FBG rain gauge is carried out. After experiment data analysis, the detection precision of this FBG rain gauge is 15.4/.tm which is almost two orders of magnitude higher than that of the existing rainfall measurement device. The experimental data confirm that this FBG rain gauge can achieve rainfall measurement with high precision.展开更多
Using effective width of load and distribution coefficient of moment is a kind of simplified method in the design of continuous reinforced concrete slabs, which is widely used in engineering design. In this paper, thr...Using effective width of load and distribution coefficient of moment is a kind of simplified method in the design of continuous reinforced concrete slabs, which is widely used in engineering design. In this paper, through the analysis of load-bearing states of continuous slabs restricted by the main beams under concentrated loads, the effective width of load and distribution coefficients of moment of a continuous slab are obtained with the principle of equivalent loads. On the basis of the data of a 5-span continuous reinforced concrete slab, the formula of effective width is deduced and the distribution coefficients of moment for the mid-span and supports are given.展开更多
基金supported by the National Natural Science Foundation of China (Nos.60808020 and 61078041)the Tianjin Research Program of Application Foundation and Advanced Technology (No.10JCYBJC07200)
文摘A novel technique for calibrating crucial parameters of chassis components is proposed,which utilizes the machine vision metrology to measure 3D coordinates of the center of a component's hole for assembling in the 3D world coordinate system.In the measurement,encoding marks with special patterns will be assembled on the chassis component associated with cross drone and staff gauge located near the chassis.The geometry and coordinates of the cross drone consist of two planes orthogonal to each other and the staff gauge is in 3D space with high precision.A few images are taken by a highresolution camera in different orientations and perspectives.The 3D coordinates of 5 key points on the encoding marks will be calculated by the machine vision technique and those of the center of the holes to be calibrated will be calculated by the deduced algorithm in this paper.Experimental results show that the algorithm and the technique can satisfy the precision requirement when the components are assembled,and the average measurement precision provided by the algorithm is 0.0174 mm.
文摘A novel fiber Bragg grating （FBG） rain gauge is proposed in this paper to achieve high precision rainfall measurement. One core sensitive FBG, a temperature compensation FBG and a mechanical transition system construct this novel FBG rain gauge. Sensing principle of this FBG rain gauge is explained in detail, and its theoretical calculation model is also established, which shows that the relationship between center wavelength of sensitive FBG and external rainfall has very good linearity. To verify its detection performance, the calibration experiment on one prototype of this FBG rain gauge is carried out. After experiment data analysis, the detection precision of this FBG rain gauge is 15.4/.tm which is almost two orders of magnitude higher than that of the existing rainfall measurement device. The experimental data confirm that this FBG rain gauge can achieve rainfall measurement with high precision.
文摘Using effective width of load and distribution coefficient of moment is a kind of simplified method in the design of continuous reinforced concrete slabs, which is widely used in engineering design. In this paper, through the analysis of load-bearing states of continuous slabs restricted by the main beams under concentrated loads, the effective width of load and distribution coefficients of moment of a continuous slab are obtained with the principle of equivalent loads. On the basis of the data of a 5-span continuous reinforced concrete slab, the formula of effective width is deduced and the distribution coefficients of moment for the mid-span and supports are given.
