A Compound Control System for FR4-Based Electromagnetic Scanning Micrograting

Fan Yu,Quan Wen,Zhiyu Wen,Hongjie Lei,Liangkun Huang

doi:10.3390/electronics8070770

Fan Yu, Quan Wen + Show 3 more

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https://doi.org/10.3390/electronics8070770

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Abstract

This paper presents a compound control system for precise control of the flame-retardant 4 (FR4)-based electromagnetic scanning micrograting. It mainly consists of a frequency controller and an angle controller. A dual closed-loop structure consisting of a current loop and an angle loop was designed in the angle controller. In addition, the incremental proportional–integral–derivative (PID) control algorithm was designed in the current loop, and the fuzzy-PID control algorithm was employed in the angle loop. From the experimental results, the frequency controller can effectively track the real-time resonant frequency of the scanning micrograting with a tracking accuracy of 0.1 Hz. The overshoot of the scanning micrograting is eliminated. Compared to an open-loop control system, the control system presented in this work reduces the steady-state error of the scanning micrograting from 1.122% to 0.243%. The control accuracy of the compound control system is 0.02°. The anti-interference recovery time of the scanning micrograting was reduced from 550 ms to 181 ms, and the long-term stability was increased from 2.94% to 0.12%. In the compound control system presented in this paper, the crucial parameters of the FR4-based electromagnetic scanning micrograting, including motion accuracy, anti-interference ability, and long-term stability, were effectively improved.

Highlights

A near infrared (NIR) spectrometer has been widely used in environmental monitoring [1], agriculture [2,3], food safety [4,5,6], oil production [7], and other fields for its ability to detect the composition and content of substances quickly and nondestructively
With the development of the microelectromechanical system (MEMS) and micro-optical electromechanical system (MOEMS) technology, researchers have proposed the use of a combination of a scanning micrograting and a single tube detector to replace the conventional optical structure, which can reduce the size and cost of the instrument [8]
The scan angle is controlled by the control circuit and can be calculated according to the length of the laser scan line and the distance between the optical screen and the scanning micrograting

Summary

Introduction

A near infrared (NIR) spectrometer has been widely used in environmental monitoring [1], agriculture [2,3], food safety [4,5,6], oil production [7], and other fields for its ability to detect the composition and content of substances quickly and nondestructively. NIR spectrometers have a common structure of using a fixed diffraction grating and an InGaAs detector array. With the development of the microelectromechanical system (MEMS) and micro-optical electromechanical system (MOEMS) technology, researchers have proposed the use of a combination of a scanning micrograting and a single tube detector to replace the conventional optical structure, which can reduce the size and cost of the instrument [8]. The actuation mechanisms can be mainly divided into four categories: electrostatic [9], electrothermal [10,11], electromagnetic [12,13,14,15], and piezoelectric [16]. The electromagnetic actuation mechanism is widely used for its large driving torque, linear mechanical properties, and low driving voltage. Electromagnetic coils are more suitable for integration into the flame-retardant 4 (FR4)-based

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Results

Conclusion