| Tactile perception is a basic function of living organisms,allowing us to accurately perceive,grasp and control different objects,and is an important way to interact with the environment.It is precisely because of the importance of touch that tactile sensors have been a hot research direction in recent years.In the medical field,minimally invasive surgery is very popular due to its advantages of small incision,less pain and quick recovery.However,due to the lack of tactile feedback,doctors cannot directly touch tissues and organs during surgery,so many tactile sensors have been developed to solve this problem.Among them,traditional light intensity modulated tactile sensors are suitable for minimally invasive surgery because they are free from electromagnetic interference,low cost and small in size.However,most of the current light intensity modulated sensors can only sense axial force and shear force,and its modulation method is complicated.In this thesis,a new type of light intensity modulated tactile sensor is studied for these problems.Specific work includes:(1)The principle of the reflective light intensity modulation tactile sensor is studied,and the light intensity modulation characteristics under different optical fiber parameters are simulated by Matlab,and the actual light intensity characteristic curve is obtained by experiment.The 3D model of the sensor structure is carried out by SolidWorks and the static mechanical simulation of the force-sensitive structure is carried out by ANSYS.A cross-shaped reflective surface and a coaxial fiber bundle are designed,so that the sensor can not only sense axial force,shear force,but also axial torque.The sensor prototype was prepared by 3D printing technology.(2)Based on LabVIEW,the host computer program for demodulating light intensity signal is developed.The program interface is simple and easy to understand,which can be used for the calibration and measurement experiments of the force/torque of each axis.(3)The calibration and measurement experiments of force/torque are carried out on the sensor,and the performance analysis is carried out in terms of sensitivity,accuracy and repeatability.The experimental results show that the light intensity modulated tactile sensor designed in this thesis has good sensing performance. |
