Position And Orientation Measurement Of Motion Platform In The Bogies Parameter Detection Facility

With the development of technology and the improvement of people’s livingstandard, convenient transportation has gradually become an important factoraffecting people’s quality of life, and as an important part of the transportation railwaylocates in an extremely important position. In recent years, in order to meet China’sgrowing capacity requirement, China railway carried out several speed accelerations,the original tense capacity is relieved to some certain extent, at the same time, peopletravel more convenient, but with the increasing of vehicle velocity, rail train partsperformance requirements are also constantly upgrading.Bogie as key parts of rail train, is essential for the effect of train performance,and become one of the core research fields of rail train. The parameters such as thelongitudinal, lateral stiffness rotational stiffness of the first suspension, andlongitudinal, lateral stiffness rotational stiffness of the second suspension produceimportant impact to rail train running stability, curve negotiation ability and thecomfort of passengers. In order to ensure that the performance of rail train to meet theoperational requirements, we must test the bogie parameters. Bogie parameters testplatform can be loaded pressure on the bogie through its three six DOF motorialloading platforms, detecting the relation between force and displacement, so that thestiffness of the bogie can be valued. This platform can also be used to simulate theactual running conditions of the bogie. Because the bogie parameters test platformmoving the three and six degrees of freedom loading platform by stretching and thedrawing back of liquid actuators, and the pose change determination does notaccurately reflect the platform loaded actuator expansion amount, loadinginaccuracies will not only make the measurement results showed a larger deviation,severely can also cause damage to the bogie and the platform itself. Therefore weneed to design a set of system can calculate position and orientation of six freeloading platform in real-time, proving the judgement of the correctness of loadingconditions, providing feedback to control loading system, making the platformloading to bogie meet the set requirements, ensuring the accurate measurement of the bogie parameters.Based on the comparison of six degree of freedom platform position andorientation measurement methods, and according to the measurement environmentand measurement requirements, This thesis selects direct contact measurementmethod detect the position and orientation of the loading platform with six degrees offreedom. By improving the traditional Stewart six degree of freedom platform, andfixed the Stewart platform to the six DOF loading platform, converting the problem todetect the position and orientation of six degree of freedom loading platform to theproblem to detect the position and orientation of the Stewart platform. Using theStewart platform of six DOF motion platform pose positive results can be transformedinto the six degrees of freedom corresponding loading platform position andorientation.To complete the detection designing of the six degrees of freedom of loadingplatform position and orientation measurement, this thesis carried out in theMatlab/Simulink platform to build software model of real-time forward solution onthe Stewart platform, the model can be input to the Stewart platform in the sixconnecting rod length variation can be quickly and accurately solving pose parameterscalculated six corresponding motion platform. Then, the correctness of softwaremodel is verified by test, in the Solidworks platform and the practical environmentresults. Results showing that, using the Simulink module to build can calculate theposition and orientation of platform rapidly and accurately, and can meet therequirement of real-time solution for six degree of freedom loading platform.In this thesis, through building of hardware and software of position andorientation detection device, we can achieve the parameter of position and orientationof loading platform in real-time and accurately, providing guarantee to bogieparameters determination.