Research On Vibration And Workpiece Surface Roughness Of Industrial Robot Belt Grinding

The grinding vibration is one of the important factors that affect the surface quality and production efficiency of workpiece when using industrial robot and abrasive belt machine for grinding and finishing.In this paper,the grinding system composed of industrial robot abrasive belt machine is studied.The grinding vibration is taken as the main research object,and the vibration is taken as the link to connect the process parameters and the workpiece surface roughness.The relevant parametric model is established.The experimental verification is carried out through the built experimental platform,and the surface roughness prediction model is further optimized.Firstly,the dynamic equation of belt grinding system is established based on the simplified model and grinding force model of belt grinding system,and the transfer function of belt grinding machine is obtained;the process factors and processing stability grinding conditions affecting grinding vibration are analyzed.Secondly,the contact stiffness model between the abrasive belt machine and the workpiece is established,and the calculation method of the natural frequency of the robot grinding system is derived by using the contact stiffness.Using the built industrial robot abrasive belt machine grinding system experimental platform,multiple groups of experiments are designed to change the normal pressure provided by the robot,the workpiece feed speed and the speed of the abrasive belt machine The vibration information of the grinding system is measured by the experimental modal analysis method to further verify the accuracy of the established modal model.Then,the acceleration signal of each group of experiments is measured by direct measurement method,and the signal is smoothed by software programming.After twice integration in frequency domain,the acceleration signal is converted into displacement signal in time domain.Using the wavelet packet analysis method,combining with the natural frequency of the system calculated above as the basis function,the displacement signal of the workpiece is decomposed and reconstructed by wavelet packet,and the energy ratio of each node is calculated.The frequency with larger energy is selected to do amplitude frequency and phase frequency transformation,and the amplitude and phase of the corresponding frequency signal are obtained,so as to obtain the vibration equation of the workpiece clamped at the end of the robot The equation can be used as the main theoretical model for surface roughness prediction.Finally,the formation mechanism of the workpiece surface topography is analyzed,and the grinding process trajectory is superimposed on the vibration equation of the workpiece.The surface topography of the workpiece is simulated,and then the surface roughness of the workpiece is calculated.By comparing the calculated roughness with the measured value,the surface roughness prediction model is further optimized through error analysis and parameter adjustment,and subsequent verification experiments are carried out.The results show that the optimized prediction model has higher accuracy and smaller error,which provides a reference for practical production application.