基于扩频理论的结构健康监测多传感应力波通信方法  

Spread Spectrum-Based Multi-Sensor Communication Using Stress Wave for Structural Health Monitoring

作　　者：洪晓斌[1] 黄景晓 许维蓥 刘桂雄[1] 

机构地区：[1]华南理工大学机械与汽车工程学院,广东广州510640

出　　处：《华南理工大学学报（自然科学版）》2015年第5期8-16,共9页Journal of South China University of Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(51305141);广东省自然科学基金资助项目(2014A030313248)~~

摘　　要：为满足特殊环境下结构健康监测多传感参量的通信需求,提出了一种基于扩频理论的多传感应力波通信方法.该方法以应力波为传感信息载体,将同一区域的传感器数据按重要程度分成多组双通道信号,并用m序列码作为扩频码展宽基带频谱以区别不同组间信号,采用Walsh码作为地址码以区别同组传感数据;利用信号前后码元间载波相对相位的变化来调制传递传感信息,同步处理后经载波同步解调,再与每组传感器的伪扩频码进行相关解扩处理,经判决处理后恢复原始各个通道的二进制传感信号.钢缆线水下环境的通信实验结果表明:发射速率为50 b/s时的应力波通信效果(SWCE)值较速率为400 b/s时提高了24%,在256位传感信息下仍可实现无误码通信;当发射端压电陶瓷浸入水中而接收端处于空气环境中时,单通道与双通道的接收信号幅值较空气环境下增加了20%,SWCE基本不变.In order to meet the requirements of multi-sensor communication for structural health monitoring in special environments,a new communication method using multi-sensing stress wave,which is on the basis of spread spectrum,is proposed. In this method,stress wave is utilized as a message carrier,all sensor data in the same area are grouped into some sets of dual-channel signals according to their importance,m sequence code is used as a spread spectrum code to broaden the baseband spectrum for distinguishing signals between two different groups,and Walsh code is used as an address code to distinguish different sensors in the same group. Moreover,the change of carrier＇s relative phase between neighboring symbols is utilized to modulate transporting information,and the received signal is synchronized before the synchronous demodulation of the carrier. Then,the correlation dispreading of demodulated signal is executed by the pseudo-noise code of each sensor group. Finally,the original binary signal is recovered after the judgment of each channel to gain the corresponding sensor data. The proposed method is applied to the communication of underwater steel strands. The results show that,when the emission rate changes from 400 b / s to 50 b / s,the stress wave communication effectiveness（ SWCE） increases by 24%,and error-free communication can be realized for 256-bit sensor information; and that,when the PZT transmitter is put in the water instead of in the air,the received signal amplitudes of single and double channels both increase by 20%,while the SWCE keeps almost invariant.

关 键 词：多传感信息 扩频 应力波通信 结构健康监测 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]