| With the continuous improvement of China’s economic strength and people’s living standards,the automobile industry has made great progress.In recent years,the rapid development of new energy vehicles has promoted the automobile industry to a higher level.However,with the continuous increase of car ownership,the corresponding problems such as energy shortage,environmental pollution and traffic accidents also follow.In many types of traffic accidents,rear-end accidents account for nearly 40% of the total traffic accidents,the accident of car rear-end large truck is the most serious one that causes personal injury and property loss.Therefore,the current national requirements for vehicle passive safety are more stringent.The national standard GB 11567-2017 issued by China sets mandatory technical requirements and corresponding test procedures for the rear lower protection devices of relevant types of vehicles to ensure that they have sufficient blocking protection.At present,the corresponding test bench and other equipment for testing the reliability of protective devices are still non-standard instruments,some of the test equipment is inconvenient to operate and the automation level is not high.Therefore,the study on RUPD test bed for commercial vehicles is a necessary requirement,which is of great significance to improve the passive safety of vehicles and reduce the casualties and economic losses caused by traffic accidents.Firstly,in this paper,the technical content of the relevant national standards of home and abroad is analyzed and summarized to determine the design requirements of the RUPD test bed.Mainly,it includes the size of the loading component,the size of the test load,the measurement range of deformation and loading head moving range and other parameters.According to the design requirements,the overall design scheme of the lower protective device test bed is developed.The whole test bed mainly includes mechanical system,hydraulic servo control system and loading point visual positioning system.The Solid Works software is used to design the 3D model of the overall structure of the test bed,and the main parts of the hydraulic servo control system are calculated and designed on the basis of the test requirements.For the loading point visual positioning system,the camera calibration test of the selected industrial camera is carried out by Using Zhang’s calibration method,and the internal and external parameters of the camera are obtained,and the average reprojection error of the camera is calculated to be 0.055 pixels,indicating that the parameters obtained in the calibration process can accurately reflect the projection relationship of the camera imaging process.According to the test in the process of need to load demand of different position of the protective device,an implementation scheme of loading point positioning using monocular vision is proposed.The relative position relationship between the rear lower protection device and the camera（loading head）is solved by using the image information,and then the loading head in the mechanical hydraulic system is guided to load the loading program for different loading points,then guide the loading head in the mechanical hydraulic system to load the loading program at different locations.With the corresponding experiments,verify the rationality and accuracy of the system design.Finally,Hyper Mesh software and ANSYS Workbench software are used to analyze finite element analysis on the pressure sliding platform mechanism and beam mechanism,which are the core stress components of the test bed.When the loading position is set as the maximum ground height and maximum loading load allowed in the national standard,the maximum equivalent stress and other checking parameters of each component are within the safety range.It is proved that the static stress intensity of the whole structure of the test bench meets the test requirements. |
