Analysis And Extraction Of Polishing Force Signal During Magnetorheological Plane Finishing

In the magnetorheological plane finishing process,the polishing force is an important physical quantity reflecting the magnetorheological finishing process,but the structure limitation of the polishing machine makes the polishing force cannot be directly collected.In this paper,finite element method,system identification theory and signal analysis and processing methods are used to analyze and extract polishing force in the process of magnetorheological plane finishing.Finite element modeling is carried out for the workpiece carrying device of magnetorheological plane finishing machine,and the frequency response data of the workpiece carrying device system is obtained by analyzing the dynamic response performance of the system.Using the system identification theory and method,the frequency response characteristics of the workpiece carrying device system are analyzed.Combined with signal analysis and processing methods,the force measurement signals in the polishing process are analyzed and processed.The polishing force can be extracted as accurately as possible from the actually collected force signal.The main work of this article is as follows:(1)Finite element simulation analysis of workpiece carrying device.Based on Ansys finite element analysis software to perform finite element simulation analysis on the workpiece carrying device of the magnetorheological plane finishing machine.The natural frequency of the workpiece carrier system is obtained through modal analysis and harmonious response analysis,and the frequency response of polishing force during magnetorheological plane finishing is mastrerd.Through dynamic simulation,the dynamic response performance of the workpiece carrier system is analyzed,and the frequency response data of the workpiece carrier in the three directions of X,Y,and Z are obtained.It provides the basis for the identification and analysis of the workpiece carrier device system of the magnetorheological plane finishing machine.(2)System identification of workpiece carrier device.Based on the system identification theory,the frequency domain identification method is used,based on the frequency response data of the workpiece carrying device obtained through simulation above,the transfer function of the workpiece carrying device system in the three directions of X,Y and Z is identified.Analyze the frequency response characteristics of the system to provide a basis for the subsequent extraction of polishing force from the information collected by the dynamometer.Based on the magnetorheological plane finishing machine,experiments are carried out to obtain the response curve of the workpiece carrying device system,and the response curve of the transfer function is compared with the response curve of the workpiece carrying device system to verify the correctness of the established transfer function.(3)Establishment of mapping relationship between polishing force and dynamometer measurement signal.The force signal collected by the dynamometer is analyzed in frequency domain,the noise frequency range is defined,and points out that the polishing force signal belongs to a low-frequency signal under a strong noise background.The trend signal and wavelet threshold denoising are performed on the measured signal to eliminate the noise and interference components contained in the original signal.Based on wavelet packet transform,the pre-processed signal is analyzed in time-frequency domain,and the relevant characteristic frequency band signal is reconstructed.Based on the frequency response characteristics of the workpiece carrier system and the time-frequency domain characteristics of the dynamometer measurement signal,the measurement signal is processed,the polishing force is extracted from the signal measured by the dynamometer.The mapping relationship between polishing force and dynamometer measurement signal is established.