Self-Capacitance Proximity and Tactile Skin Sensor With Shock-Absorbing Structure for a Collaborative Robot

Human collaborative robots (HCRs) work in close cooperation with humans. The proximity and tactile sensors placed on the HCR surface ensure the safety of humans working with the robots. However, many of these sensors do not have a collision absorption function. In this paper, we propose a self-capacitance proximity and tactile skin sensor with a shock-absorbing structure for HCRs. We evaluated the shock absorption performance and the proximity and tactile measurements of the prototype sensors using different thicknesses of the soft layer, which acted as a shock absorber. Results confirmed that when the thickness of the soft layer increased, the shock absorption function also increased, but the contact detection sensitivity decreased. In addition, we evaluated the collision between the robot with the sensor and an object when the robot moved. The sensor could absorb the impact of the collision between the robot and the object. Furthermore, multiple sensors placed on the robotic arm could detect an object before and after making contact in real time. We proved that the proposed sensor system with the shock absorber is reliable and can be used as a proximity and tactile skin sensor for HCRs.