Soft actuators with screen-printed curvature sensors

Castable elastomers have been used to fabricate soft fluidic actuators and the technique scales well from prototyping to mass manufacturing. However, similarly scalable techniques for integrating strain or curvature sensors into such devices are still lacking. In this paper, screen-printed silver conductors are shown to serve as curvature sensors for soft fluidic actuators. The sensors are realized in a single printing step onto elastomer substrates. Resistance measurement allows estimating the curvature of soft actuators, limited by the hysteresis of the sensors. These sensors can detect if the motion of an actuator has been blocked, clearing the path towards simple-to-fabricate soft robots that react to their surroundings.