一种改进小波阈值函数消噪法及其在岸桥起升减速箱中的应用

An improved wavelet threshold function denoising method and its application in lifting gearbox of quayside crane

岸桥是港口机械中的重要装卸设备,在岸桥起升机构的日常工作中,对其减速箱高速轴进行状态监控的信号(振动信号)中存在大量噪声的干扰,采用传统消噪法对其进行消噪的效果并不理想,为此,提出了一种改进的小波阈值函数消噪法。首先,对小波阈值与小波阈值函数进行了对比、选择与改进;然后,采用改进小波阈值函数消噪法与软、硬阈值函数消噪法、自适应小波阈值函数消噪法,分别对仿真信号进行了消噪实验,并对各自的消噪效果进行了比较;最后,采用相同的改进小波阈值函数消噪法和其它消噪法,对某岸桥起升减速箱的振动信号进行了处理,对各自的消噪结果进行了定量分析比较。研究结果表明:在仿真实验中,经过改进小波阈值函数消噪法处理后的信号的信噪比最大,为23.0124 dB,且均方根误差最小,为0.2563 mm/s^(2);在工程应用中,改进的小波阈值函数消噪法对振动信号的消噪效果要好于传统的消噪方法;由此可见,改进小波阈值函数消噪法可以提高消噪后信号的信噪比,降低均方根误差,有效消除噪声对有用信号的干扰。

The status monitoring signal(vibration signal)of the reduction gearbox of shore bridge hoisting mechanism,as one of the important loading and unloading equipment of port machinery,was disturbed by a lot of noise,and the effect of traditional denoising method was not ideal.Aiming at the problem,an improved wavelet threshold function denoising methodwas proposed.Firstly,the wavelet threshold and wavelet threshold function ware compared,selected and improved.Then,the proposed method,soft and hard threshold function denoising method,and adaptive wavelet threshold function denoising method were used to denoise the simulation signal,and the de-noising effects were compared.Finally,the same denoising methods were used to deal with the vibration signal of a quay bridge in Shanghai port,and the results of denoising were analyzed quantitatively.The results show that the signal-to-noise ratio of the signal processed by the improved denoising method is 23.0124 dB,and the root mean square error is 0.2563 mm/s^(2) in the simulation experiment.In engineering application,the improved denoising method has better effect on vibration signal denoising than the traditional method.In conclusion,the proposed improved denoising method can improve the signal-to-noise ratio of signal after denoising,reduce the root mean square error,and effectively eliminate the interference of noise to useful signals.