A Study On Flexible Measuring System Based On CMM

With the increasingly fierce competition of market,products are demanded with T,Q,C,S,which means shorter time,better quality,less cost and better service.Rapid acquisition of high-precision coordinate data from parts having complex geometry is one of the most important techniques in modern manufacturing process.Among many coordinate acquisition methods,Coordinate measuring machine are widely used in manufacturing industry,such as aero and space,vehicle,shipbuilding,equipment building and mould manufacturing.Coordinate measuring machines with mechanical touch probes have been well established which have resolution of the scale of 0.5μm, but the measurement processing is time-consuming,and need a lot of manual work.In this thesis,based on a 3D-Coordinate measuring machine with integrated vision and laser triangulation system,a novel flexible measuring system is presented. Some subjects in flexible coordinate measuring machine are investigated,including the sensor integration,the 3D information acquisition based on vision and laser scanning,the CAD model information acquisition,geometric character detecting and coordinate fitting.It has potential applications in manufacturing problems such as metrology,inspection,and reverse engineering.Main works in this thesis include:1 The integration of mechanical probe of CMM and laser triangulation sensor and the vision system is studied.The mockup of the multi-sensor system is built and tested.2 The 3D information acquisition based on vision and laser scanning is realized.3D information of object is acquired by laser triangulation scanning,shape from silhouette,and stereo vision.Compared to mechanical probe,these methods can measure the object less accurate,but they are much faster.The result of these methods can be used in automatic position as the base of intelligent measurement path planning.3 The CAD model information acquisition is realized by using the SolidWorks API.A frame work of program is built by Visual Basic 6.0.The geometric character and tolerance information of object are extracted in this program.4 A method of geometric character detecting and coordinate fitting is presented.In our stereo vision,only edges are matched to get 3d edges of the object. These 3D edge characters acquired by vision system can be used as the flag in coordinate fitting.The orientation and position of the object can be determined,which is also used as the basic of measurement path planning.