Modeling of the working accuracy for robotic belt grinding system for turbine blades

This article presents a calibration model for the whole grinding system to enhance its accuracy, because of the problem of low accuracy of the robotic belt grinding system which is due to the low absolute positioning accuracy of the robot as well as the deformations of the turbine blades and grinding tool under the grinding force. First, the transition matrix of system working accuracy was established and the corresponding evaluation criterion was put forward for the systemic features. Then the deformation of the turbine blades and grinding tool were analyzed and modeled, respectively, and the model of the absolute positioning accuracy of the robot was established based on the geometrical error as well as the compliance error. Finally, based on the models above, a method of error compensation was presented and the flowchart was given. The experiments show that the absolute positioning accuracy of the robot (the average value reduces from 1.186 to 0.154 mm) and the accuracy of the whole grinding system (the average grinding force is 20.4N which is very close to the predetermined 20 N) have been effectively improved, which prove that the method can help to expand the application scope of the robotic system.