Design of novel sensing technique for micro-strain measurements using Fiber-Bragg Gratings

Design of novel sensing technique for micro-strain measurements using Fiber-Bragg Gratings

Wankhade, Aditya (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Precision and Microsystems Engineering)

Goosen, J.F.L. (mentor)

Delft University of Technology

NERI

2020-11-27

Fiber Bragg Gratings and its application in various fields is an active area of research. Its high sensitivity, low cost and maintenance is gaining high attention in the various upcoming fields. As the Fiber Bragg Gratings can be used in various capacities, its operation as sensor is explored in this research. The primary aim of this research is to measure the strain which is induced in the
high-speed pick and place machine arm while picking up the micro-electronic chip from the silicon wafer. As this research focuses on measuring the strain by a sensor, it naturally deals with the fundamental constituents involved in it, namely: the type of sensor head, the placement of sensor and the interrogation system. The research starts with reviewing all the optical approaches for
strain measurement and is then focused to Fiber Bragg Gratings due to its obvious advantages and the interest of company in it. A brief literature review is presented in chapter 2, where the working of a Bragg grating, its various manufacturing techniques, and the principle on which it works is mentioned. This is coupled with the various applications it provides and further its application as a sensor which is demanded in this research is explored.
Determining the types of sensor heads which are formed by varying index modulation in the core of the optical fiber, the various interrogation techniques used for demodulating the reflected wavelength to detect the measurand are mentioned in chapter 3. Considering all the advantages and disadvantages, Mach-Zehnder Interferometric demodulation is selected for its suitability and
sensitivity in this research problem. An experimental setup has been designed to display the connection between various parts and the flow of light from the input source to the final detector. The strain to be measured on the selected part of the machine, is very small, hence an amplification mechanism is proposed as a solution to this, thus amplifying the input strain and providing the Bragg grating sensor with a stronger input. This amplification mechanism also solves the issue of coupling or positioning of the sensor in the machine to attract the maximum strain possible. Numerical analysis was performed to analyze the optimum geometry of the amplification mechanism by which maximum strain can be detected by the sensor, given the design space constraints. Simulations were made regarding the same. A compact amplification device that could fit in a 2.5 cm × 2.5 cm box is designed which is suitable for the physical space available in the system. The strain amplification of 5.64 is obtained with the percentage error between the numerical analysis and the simulations to be 3.521 %.
A conclusion is made based on the parameters chosen, various recommendations and limitations have been listed to solve this problem in other possible ways to obtain better results.

Optomechatronics
Fibre Bragg Gratings
Optical sensors
Amplification structure
Sensing Technology
Strain sensor
Optics

http://resolver.tudelft.nl/uuid:a7593211-74ff-49e7-b7c7-4e6c36cd45c8

2023-01-01

Student theses

master thesis

© 2020 Aditya Wankhade