Design And Implementation Of Coordinate System Generation And Transformation Based On CMM

CMM is an instrument used to measure parts and components accurately in industrial design and production.It has been widely used in manufacturing by virtue of its high detection efficiency and simple operation.The establishment of coordinate system is a crucial link in the industrial design and production of CMM,which is the basis of all measurement work.Therefore,a coordinate system generation and conversion system for coordinate measuring machine is designed and implemented.By investigating and summarizing the use of coordinate system in production practice,the operation of coordinate system is designed into ten functions of the system.It includes2 D coordinate system generation,2DCAD alignment coordinate system generation,generation coordinate system generation,rotation translation coordinate system transformation,fitting coordinate system generation and so on.The generation of the new coordinate system can be roughly divided into two ways.One is to directly generate the elements provided by users;the other is to obtain the transformation relationship between the reference coordinate system and the new coordinate system,and then transform the reference coordinate system according to the transformation relationship to get the new coordinate system.Among them,the second way is the most commonly used,and calculating the transformation relationship between the reference coordinate system and the new coordinate system is the focus and difficulty of this topic.Based on the basic theory of spatial geometric transformation and the relevant knowledge of numerical analysis,several methods for calculating the coordinate system transformation matrix,including the least square method and Newton iterative method,are discussed.The system realizes the visual interface through Qt,and uses the Open Cascade thirdparty library to calculate the coordinate system transformation.Finally,by comparing the test results of the system with the theoretical results,it is found that the two are basically consistent,and the error is controlled within 0.00005 mm,which can well meet the user’s functional requirements and precision requirements for coordinate system transformation.