Research On Optical Displacement Senor And Method For Measuring Absolute Displacement

Displacement sensors are very important measuring instrument and widely used in various technologic and industrial fields. A novel displacement measuring principle using polarized light detection is presented in this dissertation. Based on this principle, the design of mechanical, optical and electrical parts is accomplished, and a prototype sensor is produced. Finally, the test on this sensor is done. This thesis is divided into the following parts:Chapter 1 introduces the research background including some introductions on some kinds of displacement sensors, the development and application of wide-range displacement sensors.Chapter 2 analyzes some basic theories of polarized light including the phenomena of polarized light and its principle, the Malus Law, and the theory of electrical modulating on light.Chapter 3 describes the displacement sensor using servo-comparison method. The servo-comparison method, the components of the sensor, the hardware system and the software system are described in detail. In addition, the prototype sensor is produced and the test on it is accomplished.Chapter 4 introduces the method for measuring absolute displacement. Based on the characteristics of the servo-comparison method and an additional apparatus for deciding the certain periods, an absolute displacement sensor with a wide measuring range is realized. In addition, a new method for measuring displacement through displacement-time conversion is presented. Using this method, an all-optical displacement sensor which has a strong resistance to disturbance and a quite high precision can be realized.Chapter 5 analyzes the result of the test on the prototype sensor. A situation of the prototype sensor functioning in an industrial field is introduces. These experiments demonstrated the wide range of the sensor which can reach 40m, the relatively high precision and reliability. Additionally, the result of the absolute displacement measurement experiment is also presented.Finally, Chapter 6 made a conclusion and the directions for further works are also pointed out.