Research On Grinding Force Model Of Wind Power Blades With Cup Wheel

With the rapid development of China's wind energy industry,the capacity of wind turbines is increasing year by year,which makes the manufacturing and maintenance of wind power blades increasingly onerous.In the manufacturing process system of wind power blades,it has become a trend to use grinding robot to grind curved surface wind power blades.The existing robots can only control the normal force stability during the grinding process,and cannot obtain the tangential force data during the grinding process at the same time.However,the tangential grinding force is one of the important factors affecting grinding phenomena such as vibration of grinding end,grinding efficiency and grinding temperature field.Aiming at the above problem,a grinding force model for wind power blade grinding with the cup wheel was studied in order to achieve the real-time calculation of the grinding force during the curved surface grinding process.Firstly,an analytical model of grinding force for grinding curved surface with cup wheel was established.By analyzing the grinding trajectory of the grit in the grinding contact area,and studying the static force of the grit,the analytical formula of the grinding force of the grit was obtained.Since not all prominent grits participate in the grinding process of the cup wheel,the gauss distribution statistical method was used to calculate the number of grits per unit area in the grinding contact area under different grinding depths,so as to obtain the effective number of grits participate in the cutting and friction grinding processes.By multiplying the analytical formula of grinding force of a single grit and the effective number of grinding grits per unit area and integrating them in the grinding contact area,the analytical model of grinding force for grinding curved surface with cup wheel was obtained.Secondly,the DEFORM-3D finite element simulation software was used to build the simulation environment for grinding curved surface workpiece with cup wheel to verify the accuracy of the analytical grinding force model of cup wheel.Since there is no tool similar to the grinding wheel in the finite element software tool library,MATLAB was used to establish a three-dimensional surface with similar morphology characteristics to the actual grinding wheel,and the curved surface was imported into modeling software to obtain the model of the cup wheel.The grinding wheel and curved workpiece were imported into DEFORM-3D for finite element simulation.The results show that the analytical model is in good agreement with the simulation data,and the error analysis of the simulation results was carried out.By summarizing the grinding force data under different grinding parameters,it is found that the grinding force is inversely proportional to the grinding speed and directly proportional to the grinding depth and feed rate.Finally,the compliant grinding system of wind power blade robot was designed and built,and the grinding force measurement experiment of cup wheel was carried out with this grinding system.The analytical grinding force model was further verified through the experiment,and the results show that the grinding force model has good accuracy.The friction force and the cutting force ratio in the grinding force were further studied,and the conclusion is drawn that the friction force ratio in the grinding force is much larger than the cutting force.The establishment of the grinding force prediction model for grinding curved surface with cup wheel provides an accurate theoretical basis for the research of grinding temperature field and grinding efficiency.