Design of an Optical Position Sensor for Microfiber Actuators

This thesis introduces a new type of sensor that detects the position information of a paramagnetic microfiber and transforms it to computational electrical signal. The original purpose of the sensor is to solve the problem of feedback signal detection of the microfiber control system, which is the problem of detecting the position information for the microfiber. The microfiber will be presented as the experimental object of this sensor to test its capability. A novel optical based approach is used to transfer the position signal to a computer scrutable signal for further analysis.;The purpose of the sensor design comes from the question of how to detect the position information in the feedback section of the microfiber control system. It is crucial since it provides the feedback for the whole control system. The information can be difficult to detect since our microfiber is designed to achieve high frequency (up to 100 ~ 1000Hz ) low range reciprocating motion and low frequency high range movement in future. Thus, a sensing system is required to be able to input high speed movement and output analytical electrical signal.;A high-speed camera can be used with an approach of image processing techniques, but considering the high-end and high-cost camera be applied in a simple purpose as in our system is inefficient, and another disadvantage relates to the image processing speed will be a limitation which will affect speed of signal detection.;A general idea of the design of the sensing system is presented in this thesis. The sensor relies on optical based sensing method. This method with related electronic components is able to sense fast speed movement and high frequency reciprocating motion. A modulation and demodulation approach is also included to eliminate the possible noise from the environment. Results are presented in the thesis to show the effectiveness of the sensing system and to indicate in general the sensor is providing a robust result for the microfiber's position analysis.