Design And Implementation Of Magnetically Resonance Compatible Tactile Sensing System

Robots,a few years ago,were only confined to the assembly lines in a manufacturing plant.But now they are making their way into the human life.Humans have five main modalities named as tactile,vision,hearing,taste and smell.Lack of any of these senses results in an incomplete interaction with one's surroundings.These modalities are also necessary for better robotic manipulation.Considering only the tactile sensing,a lot of force feedback sensors and sensing arrays have been proposed using different methods.But the main drawbacks of these sensors are that either they are incompatible with magnetic environment or they can only measure time varying forces.This study presents the design and implementation of a tactile system that can be used in an electromagnetic environment.The hardware part of the designed system has three main parts a light source,a tactile sensing array probe head,and a camera to capture the light intensity images.The laboratory prototype of a tactile sensing array probe head,made of ABS material,is designed to convert the force applied into the light signals.Fiber optics are used to transmit the light signals to the probe head from the light source and take the reflected light signals from the probe head to the camera.The probe head has 14 sensing elements where each sensing element has a diameter of 3.9 mm.Each sensing elements has its own separate independent flexible structure.This eliminates the problem of cross talk between the adjacent sensing elements.Each sensing element converts the force applied to it into optical signals.These optical signals are captured by the camera attached to the other end of the optical fiber bundle.The light intensity image captured by the camera is then processed,using image processing techniques,to extract the information about the force applied.These image processing techniques are implemented in MatLab~?.Linear regression is used to find the relationship between the force and the light intensity image.The probe head is calibrated using a commercial tactile sensor ZNHBM.After calibrating the probe head,its dynamic response is compared with the commercial sensor.In addition to this,the probe head is used to detect the shape of a cylindrical object with a flat face.The experimental results have shown the sensor's capability in measuring the force accurately.Each of the sensing element can measure the force in the range of 0-5N.Also,the proposed sensing system is cheap,light weight and non-corrosive,and can be used in harsh environments.