Robotic finger with touch

2003/03/05 Rementeria Argote, Nagore - Elhuyar Zientziaren Komunikazioa

• Materialak
• Robotika
• Kimika

This sensor allows to regulate the electrical current necessary to adjust the pressure of the robotic finger when holding an object. The heavier the object, the greater the pressure the finger must exert to hold the object and depends on the current that receives it.

This pressure sensor is designed to fulfill the same function as the touch in the hands of man. We humans intuitively calculate the force to use according to the weight of the object that we are going to catch in our hands. For example, we gently grab a flower, but make more strength to take something heavier. This is done thanks to the interaction between the touch and the muscles.

The sensor that provides robots has been made with a polymer called polypirrol. Two thin films of polypirrol are glued on an insulating tape and one of them has been put on a positive charge and the other a negative. As this polymer is conductive, the positive load contracts the film and expands the negative ones, which translates into a worsening of the pair.

The sensor is placed on the robot finger bud. Thus, when holding an object, this sensor changes the conductivity according to the pressure exerted by the fingers. As the pressure is higher the heavier it is, the conductivity of the sensor is higher and lets more current pass.

The change of conductivity of the sensor may be due to the pressure affecting the packaging of the polymer, as explained by the researchers.