一种井下机械臂通信信号滤波方法

A filtering method for underground manipulator communication signal

多自由度机械臂在煤矿井下作业时,其通信信号易受到脉冲、电磁干扰等外部因素的影响,降低信号传输可靠性,影响多自由度机械臂的灵活性和控制精度。为提高井下多自由度机械臂通信信号质量,提出了一种基于改进时频峰值滤波的井下机械臂通信信号滤波方法。根据机械臂通信信号的载波节点提取载波特征,基于希尔伯特变换理论提取传输周期特征。利用小波分解求解每一级小波变换系数,获取通信信号扰动频率,完成通信信号特征分类。引入相位补偿因子改进时频峰值滤波,根据比例因子和削减因子计算削减门限阈值,调整固定窗口长度,并采用改进时频峰值滤波滤除通信信号中的噪声,实现多自由度机械臂通信信号噪声抑制。以3自由度机械臂为试验对象,设置脉冲宽度为8µs、波特率为120bit/s,通信信号传输时间间隔为2ms、信号幅度为1,向通信信号加入30dB高斯白噪声。试验结果表明:经基于改进时频峰值滤波的井下机械臂通信信号滤波方法处理后的通信信号输出信噪比为94 dB,误码率基本稳定在0.6%,丢帧率均值由滤波前的2.9%降至0.8%,有效提高了多自由度机械臂通信信号质量和传输可靠性。

When a multi-degree-of-freedom manipulator operates in underground coal mines,its communication signal is easily affected by external factors such as pulses and electromagnetic interference.It reduces the reliability of signal transmission and affects the flexibility and control precision of the multi-degree-of-freedom manipulator.To improve the communication signal quality of underground multi-degree-of-freedom manipulator,a filtering method for underground manipulator communication signal based on improved time-frequency peak filtering is proposed.The method extracts carrier features based on the carrier nodes of the manipulator communication signal,and extracts transmission period features based on Hilbert transform theory.The method uses wavelet decomposition to solve the wavelet transform coefficient of each level,obtains the disturbance frequency of communication signals,and completes the classification of communication signal features.The method introduces phase compensation factors to improve time-frequency peak filtering.The reduction threshold is calculated according to the scaling factor and reduction factor,so as so adjust the fixed window length.The improved time-frequency peak filtering is used to filter the noise in communication signals.Thus the noise suppression of the multi-degree-of-freedom manipulator communication signal is achieved.A 3-degree-of-freedom manipulator is taken as the experimental object.The pulse width is set to be 8µs.The Baud rate is 120 bit/s,the communication signal transmission interval is 2 ms,and the signal amplitude is 1.30 dB Gaussian white noise is added to the communication signal.The experimental results show that the output signal-to-noise ratio of the communication signal processed by the filtering method for underground manipulator communication signal based on improved time-frequency peak filtering is 94 dB.The bit error rate is basically stable at 0.6%,and the average frame loss rate is reduced from 2.9%before filtering to 0.8%.The method effectively improves the communication signal quality and transmission reliability of the multi-degree-of-freedom manipulator.