Robotic Trajectory Planning And Off-line Programming For Belt Grinding Of Turbine Blade

As key components of energy conversion devices, blades’ geometric accuracy andsurface quality will determine the equipment’s performance. Robotic belt grinding is the lastmachining process, and its effect will determine blades’ surface quality. In order to get goodgrinding effect, a reasonable trajectory must be planned. The trajectory should not only ensuresatisfactory machining accuracy, but also have high efficiency.Robot trajectory planning and kinematic model are introduced firstly, which aretechnology base of robotic grinding path generation. After comparison of several multi-axialmachining trajectory planning technologies, equal chord deviation fitting method and equalscallop height method are adopted to plan the robot trajectory. Besides, these two methods areimproved because of their shortcomings in blade grinding. Area division and trimming ofblade model are carried out before trajectory planning, to define the machining area and avoidinterference. It is ensured that the vector of support shaft coinciding with blade surfacenormal at each target, which determines the robot’s pose. The coincidence of two vectors canalso make the control of contact pressure easier. In order to improve grinding efficiency, amethod to separate the grinding area is used, which allows the bigger grinder to machine asmuch area as possible.The improved methods are used to plan robot trajectory and a machining experiment iscarried out. The surface roughness, profile accuracy, efficiency and cost of three grindingmethods are compared. And effectiveness of the improved methods and advantages of roboticgrinding are verified by the experimental results. Based on the research results above, anoffline trajectory planning software module for robotic grinding of turbine blade wasdeveloped and it has been applied in practice.