Path Planning Of Robot Polishing Model-free Workpieces

As the last process of workpieces processing,polishing has an important impact on the quality of the finished workpieces.With the development of industrial intelligence,robots instead of manual polishing operations have become an inevitable trend.Free-form workpieces or small-batch workpieces,such as aero-engine blades,fan blades,etc.,often do not have accurate CAD models,and polishing of such workpieces still relies on manual work,resulting in a low degree of automation.Realizing automated robot polishing of model-free workpieces can contribute to expanding the applicable scenarios of robot polishing,improving the intelligent manufacturing level of polishing operations,and solving the problems caused by manual polishing.In this thesis,a robot active force control polishing head is designed and developed for the application scenario where robot polishing operations are performed on model-free workpieces.On this basis,the theoretical and technical problems related to the model-free workpieces local model acquisition method and full coverage polishing path planning method are studied.The main work is as follows:According to the polishing process,this thesis presents a design of an active force control polishing head.The polishing head has the advantages of high bandwidth response of polishing force and controllable coordination between polishing force and polishing speed.Using ANSYS software,this thesis provides a strength verification of the important parts in the polishing head.Finally,based on the design of the electromechanical system for the polishing head,a control framework including an industrial robot was built.Based on contact and non-contact measurement characteristics,this thesis proposes a model-free workpieces local model acquisition method for workpieces and designs a matching measurement component.Using the local model acquisition method,a mathematical expression for the local area of workpieces can be fitted at each path point.A sensor calibration method is proposed for the efficient use of measurement component.Finally,a series of normal tracking experiments were designed to verify the effectiveness of the method.To realize robot polishing of model-free workpieces,a full coverage polishing path planning method is proposed in this thesis.This method enables full coverage polishing with a preset overlap width in the polishing sub-area for model-free workpieces.To ensure the implementation of the method,this thesis also proposes rules for the division of the polishing sub-region and the way to save the boundary points of the region.The normal contact width model of the polished pad was established using Hertz contact theory,and the accuracy of the constructed width model was verified by using ANSYS software.To verify the effectiveness of the proposed polishing path planning method,an experimental system was designed,and a series of polishing experiments were carried out in this thesis.The experiment uses two different free-form workpieces and sets up control experiments.In the experiments,the proposed method achieves good results with average errors of 0.42 mm and 1.3 mm,respectively,which fully verifies the effectiveness of the proposed path planning method.