Research On Optical Tactile Sensor

Tactile sensor is the most important and complex sensor,which is the foundation and core of intelligent system.In recent years,many researchers are studying the pressure sensing of tactile sensors,and also trying to use various sensing principles to develop tactile sensors with small structure,high sensitivity,good stability and low price.At present,there are many researches on electrical sensors,but they have some obvious defects,such as easy to be affected by electromagnetic interference,complicated circuit connection and zero drift.Moreover,in the harsh environment of radiation,high and low temperature,the traditional electrical sensors are often difficult to work normally.Different from electrical sensors,optical tactile sensor has the advantages of simple structure,small size,light weight,low cost,and free from electromagnetic interference.It can work in some small or radiation environment.In this thesis,based on the requirements of tactile sensing function of intelligent machine in minimally invasive surgery,the related theoretical and Experimental Research on optical tactile sensor is carried out.The specific work includes:(1)Design and simulation part:According to the research status of optical tactile sensor,the advantages and disadvantages of common types of sensors are analyzed,and the realization scheme of tactile sensor based on light intensity modulation is proposed.In the design of the structure,a simple single point tactile sensor is selected,that is,some micro structures are added to the rod structure.Firstly,the SolidWorks software is used to design the model of structure,and then the drawn model structure is imported into ANSYS finite element analysis software for finite element simulation analysis.Finally,according to the simulation results,the optimal sensor structure is determined,and the sensor prototype is made.(2)Experiment and data processing part:The sensing experimental system based on light intensity modulation is designed and built,which includes white light source,tactile sensing head,optical fiber bundle and CCD camera.The strain sensing experiment of the designed tactile sensor is carried out,and the corresponding test is completed.Then,the image data received by the camera is demodulated by image processing technology.Finally,the relationship between the output light intensity of the fiber bundle and the stress change felt by the sensor head is obtained.The experimental results show that the sensor has good strain sensing ability.The optical sensor designed in this paper is made by using 3D printing technology.It has the advantages of simple structure,low price and no toxicity.It can also be integrated into the intelligent mechanical tools of minimally invasive surgery.Moreover,the sensor based on light intensity modulation is not affected by temperature,which is better than FBG Optical sensor.In addition,the sensitivity of the sensor is improved by introducing a spiral microstructure into the rod structure.In the demodulation system,different from the similar light intensity sensing experiments,this paper uses image processing technology to complete the light intensity demodulation.This method does not need to set a separate detector for each reflective fiber at the receiving end,so the operation is simpler and the result is more accurate.