Development of 3D printed fingerprint for robotic hands and grippers

Texture and shape recognition through applying haptic sensors are being widely explored in robotics.
Various technologies, such as vibrations, force feedback, air vortex rings, and ultrasound, are used in haptic sensing. However, the implementation of this kind of sensor may be limited, especially in robotic hands and grippers, resulting in a reduced degree of freedom created to prevent damage to the haptic sensor. This Master's thesis aims to address designing a 3D printer fingerprint pattern to enhance the body-borne vibration signal of an RH8D Adult size Robot Hand. The amplified vibration signal, generated by the fabricated 3D printer texture pattern, is recorded by a contact microphone.
This strategy allows mounting sensors inside the robot’s casing to reduce the mechanical constraint and noise background.Strategically the RH8D has been designed with removable surface parts where the 3D printed texture pattern will be mounted. To optimize the design of the surface pattern, vibration analysis is carried out by reducing the robot finger-hand to a mathematical model: damper, spring-mass system. The sensor response to kinesthetic and tactile exploration was analyzed through three experimental iterations. Three experimental iterations analyze the sensor response to kinesthetic and tactile exploration.The result of these iterations is a 3D printed surface based on thermoplastic polyurethane material, capable of raising vibrations generated by an R8HD  up to 430 \(\%\).
On the other hand, materials such as resin or polylactic acid exhibit increases of 150 \(\%\) on objects with regular surfaces. This rise of vibrations is highly recorded on the left side of the RH8D where the contact is appled. On the other hand, when the object has a smooth surface the vibration tends to reduce its amplitude.  Finally, the data provided for the third experiment is collected as a haptic data-set.