Application of photogrammetry to automated finishing operations

Buffing is usually the last and most important operation carried out during manufacturing processes, especially for use in applications that require strict tolerances. For objects with irregular geometry, this operation may have to be done manually. In an effort to automate the buffing process, robot simulation platforms can develop offline programs for specific geometries that are known beforehand. However, in the case of unknown geometries, it is required to first develop the CAD model before processing within simulation platforms. This can be done using either manual measurement of the object, which could be tedious, 3D scanning the object, which requires specialized expensive equipment, or the process of photogrammetry, which is cheap and readily accessible. This paper describes the use of photogrammetry to develop scale 3D models of irregular objects, which is subsequently used to generate tool paths for an industrial robot via offline programming, to be applied in finishing operations. The photogrammetry procedure involves compiling photographs of the target object from a 360° orientation, and using a photogrammetry software to generate the 3D model of the target object. This model is then used within the simulation software to develop the final output. A commercial photogrammetry software, Bentley's ContextCapture, is used to develop the 3D models, which are then imported to RobotStudio which can generate end-effector toolpaths for buffing operations to be carried out on the scanned object, based on the contours of the model. The offline program thus obtained is to be transferred to an IRB 1410 6 DOF industrial manipulator for execution and verification. (paper)