The Design and Modeling of a Novel Resistive Stretch Sensor With Tunable Sensitivity

Wearable technologies, interactive and safe robotic systems require an effective actuator control that highly depends on the accurate feedback from flexible and dense array of sensors. In this paper, we introduce a novel soft stretch sensor design that is applicable to distributed high strain measurements. The proposed sensor design utilizes 2-D fabrication processes to create specific profiles and stretchable mesh patterns in Constantan-polyimide laminate that are scalable and customizable. In addition to the geometrical parameters of the stretchable mesh pattern, the sensitivity in the proposed design is determined by the metal layer profile. Without considerably affecting its mechanical properties and stretchability, the profile design allows an engineering freedom to choose the scope of measurements and the sensitivity. Similar design principle can eventually produce complete sensor/circuit systems, where the circuitry and the sensing elements can coexist in a single metal laminate. In this paper, we describe the sensor design parameters and the sensor model that include the equations of deformation and resistance change as a function of the stretch. We compare the prototype test results to the model prediction. The findings provide guideline to designing customized sensors that satisfies specific size and stretch requirements.