Towards the Development of Soft Force and Pressure Sensors for Robot Safety Applications

When collaborative robots impact humans, their body parts deform which can cause surface and deep pain. Onset of pain has been determined as an acceptable injury threshold in human-robot impacts and has been related to pressure. Therefore, it is necessary to measure pressure on deformable human body parts contacted by a robot. A pressure sensor appropriate for this purpose should deform with the body part and not introduce local stiffness. In this paper, we present the design and fabrication of a soft pressure sensor. We demonstrate that the sensor matches the biomechanical response of the human forearm and that its capacitance changes linearly with applied force. In the near future, we intend to embed this sensor in a biofidelic dummy arm, with long-term goals of designing a fully sensorized dummy to measure pain caused by impact with collaborative robots.