Intelligent Tire Based Tire Force Identification And Bridge Impact Test

It is of great significance to quickly assess the service condition of existing structures due to the need for maintaining huge number of infrastructures in China.The mobile impact vibration test,which uses mobile vehicles as the structural incentives,can meet this need.Compared to traditional impact vibration test,it is more convenient,economical and time-efficient.One problem needed to be mentioned is that the vertical tire force,which is the impute load,is hard to obtain.To address this problem,this thesis introduces a vertical tire force identification method based on the fusion of multi-sensor information.In particularly,to measure the tire deflection,which is one key tire parameters needed,two methods based on the long-gauge strain sensing and computer vision are studied,theoretical derivation and experimental verification are carried out respectively.Furtherly using the measured tire force,combined with collected structural response,realizes deep structural parameter identification.The research contents and innovations of this article are as follows:(1)Aiming at the problem that the vertical tire deformation,which is needed to invert the vertical wheel force,is difficult to be continuously measured in real time,combined with the unique advantages of long-gauge Fiber Bragg Grating(FBG)sensors’ high precision,high durability and macro and micro,a tire vertical deformation measurement method based on long-gauge FBG sensors is proposed.Based on the simplified tire model,the traditional conjugate beam method,which is only applicable to straight beam structures,is modified to be extended to curved beam structures,then the vertical deformation measurement problem is transformed into the bending moment solution problem of tire conjugate structure.The results of static impact test and tire rolling test show the effectiveness of the proposed method in realizing real-time continuous measurement of tire vertical deformation;(2)During the implementation of contact measurement,the sensors are complicated to be installed and are not recyclable.To address this problem,a non-contact vertical tire force recognition method based on computer vision is further proposed.Derived from the aforementioned vertical tire force recognition method based on multi-sensor information fusion,combined with the unique characteristics of computer vision sensing,the radial deformation of the tire and the position of the measuring point relative to the tire-ground contact center are used to replace the effect of the tire vertical deformation.The center point detection method based on Hough transform is used to realize the marked point recognition,the perspective transformation is used to eliminate the influence of the sway of camera.A convenient vehicle-mounted shooting system is designed,and the proposed method is verified through the real vehicle test;(3)Using the vertical tire force obtained by the above method,combined with the monitored vehicle position through computer vision sensing,the force is distributed to the element nodes to obtain structural input load.The output response of the structure is measured by the bridge deck sensing system.Then the deep-level parameters such as the structural displacement flexibility can be identified and the structural deformation is predicted.Finally,the proposed method is verified through the test of a simply supported concrete box girder bridge.