Large-optical-path closed-loop measurement system based on two-stage actuator structure

Abstract

The invention discloses a large-optical-path closed-loop measurement system based on a two-stage actuator structure. The system is composed of a photoelectric conversion module, a digital control module and a two-stage actuator module, wherein the photoelectric conversion module can be directly connected with an optical fiber interferometer to complete the conversion from an optical signal to an electric signal, and the digital control module calculates a closed-loop feedback value of each control period according to an input signal and sends the closed-loop feedback value to the actuator module. The two-stage actuator module is composed of two actuators with complementary performance, wherein the first-stage actuator selects an actuator with a medium optical path and high dynamic performance, for example, a piezoelectric ceramic for optical fibers to compensate the feedback value, and meanwhile, due to the interference principle of light, the output of the first-stage actuator has anineffective direct current part, and the part uses a large-stroke actuator with common dynamic performance and a cm-level stroke, such as an electric optical fiber delay line, to perform the slow compensation. According to the invention, the high-dynamic and large-optical-path closed-loop measurement capability of the driving stage of the whole closed-loop system is ensured through the cooperativeuse of the two stages of actuators.

Description

technical field [0001] The invention belongs to the technical field of interferometer closed-loop measurement, in particular to a large optical path closed-loop measurement system based on a two-stage actuator structure. Background technique [0002] Optical fiber sensing technology is a new sensing technology that emerged in the 1970s. As a new member of the sensor branch, optical fiber sensors have the following advantages: sensitive measurement capabilities, and can adapt to detection fields that require higher measurement accuracy ; Response frequency bandwidth, can respond to very low frequency, large dynamic range, full light; light weight, small size. Therefore, the optical fiber sensor is easy to install and bury; the insulation performance and chemical properties are good, and it is not affected by electromagnetic radiation; for distributed detection, the optical fiber itself can be used as a part of the sensor, so the optical fiber with sufficient length can comple...

AI Technical Summary

Problems solved by technology

For the closed-loop detection system, the core of its high dynamic range is zero-bias detection based on closed-loop feedback, and the feedback compensation amount is the closed-loop detection value. When the drift of large optical path and high bandwidth exceeds the compensation capability of closed-loop feedback, the error of the entire closed-loop system increases, the measurement accuracy decreases, and even the closed-loop system loses stability

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