Edge And Angle Recognition Technology Research Based On Fiber Bragg Grating Tactile Sensing

Tactile sensing is a frontier topic in robot science research,It involves many disciplines and many complex issues.The recognition of edge and angle of object by tactile method plays an important role in the robot's perception of spatial information,such as object position,size and surface shape.It also can help robots adjusting its own position and posture.Thus,it plays an important role in accurately identifying objects and even manipulating objects.Fiber Bragg grating(FBG)sensor has the advantages of antielectromagnetic interference,moisture resistance,small size,good flexibility,distributed sensing and so on.A FBG sensor was embedded in vulcanized silicone rubber to construct a tactile sensor.The relationships between FBG reflection spectrum,central wavelength,total power and peak power of reflection spectrum with different contact angles and contact forces were discussed and analyzed when the manipulator skin was in contact with object edge,flat surface and angle,respectively.The experimental results show that when the contact force is constant,when the sensor is in contact with object edge,there is a trigonometric function relationship between central wavelength,total power of the reflection spectrum,peak power and contact angle.And reflection spectrum will appear a second peak(secondary peak)when contact angle approaches 90°.When in contact with object angle and object flat surface,central wavelength,total power of the reflection spectrum and peak power do not change with the change of contact angle,and the secondary peak always exists when in contact with the object angle.Keeping the contact angle constant,in these contact cases,the reflection spectrum drifts linearly with the contact force,the shape of the spectrum does not change significantly,and central wavelength varies linearly with the contact force,while total power of the reflection spectrum varies linearly with the contact force when contacting with object edge and object angle,and does not show regularity when contacting with object flat surface.Through the above changing rules,the edge and angle of object can be identified effectively,and this method is expected to be applied to the field of robot tactile sensing.