基于正交锁相放大器的微弱应变信号检测系统

发布时间：2018-12-29 18:56

【摘要】：在工业现场利用应变传感器进行形变测量时,被测物在小负荷作用下使得传感器输出的应变信号十分微弱。微弱信号有时甚至会被现场的强噪声信号完全淹没,这时提取有效的微弱信号将变得非常困难。针对这种实际问题,应用相关检测法设计了基于正交锁相放大器的微弱应变信号检测系统。在设计中,待测微弱应变信号通过信号调理、低噪声放大和带通滤波后与严格正交的两路参考信号进行相乘。然后,将乘法器输出信号进行低通滤波得到与待测信号幅值成正比的直流信号。对直流信号经过A/D采集和计算实现微弱应变信号的检测。经过Simulink仿真、现场实验与运行,结果表明系统能有效地抑制噪声信号,准确测量出微弱的应变信号。
[Abstract]:When the strain sensor is used to measure the deformation in the industrial field, the strain signal output by the sensor is very weak under the action of small load. Sometimes the weak signal will be completely submerged by the strong noise signal, so it will be very difficult to extract the effective weak signal. Aiming at this practical problem, a weak strain signal detection system based on orthogonal phase-locked amplifier is designed by using correlation detection method. In the design, the weak strain signal to be measured is modulated by signal, amplified by low noise and filtered by band pass, and multiplied by two reference signals that are strictly orthogonal. Then, the multiplier output signal is filtered by low pass filter to obtain DC signal which is proportional to the amplitude of the signal to be tested. The weak strain signal can be detected by collecting and calculating the DC signal. Through Simulink simulation, field experiment and operation, the results show that the system can effectively suppress the noise signal and accurately measure the weak strain signal.
【作者单位】：燕山大学河北省工业计算机控制工程重点实验室;
【分类号】：TN911.23

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