Soft actuators have recently been developed for a variety of functions. These functions include soft grippers, wearables, medical devices and artificial muscles. It is necessary for the tip of the actuator to be able to detect normal and shear forces and give accurate feedback, and this will be achieved by a sensor placed at the tip of the actuator. The new possibilities in 3D printing, specifically the combination of various materials and printing of conducting ink make it possible to have the sensor 3D printed.
A model has been derived to predict the stresses and strains under specific loads which are recreated in experiments. Four experiments on 3D printed samples containing conductive and non-conductive materials are done to determine the relations between the stress, strain and resistance of these materials to obtain more insight into the mechanical and sensory properties of these materials. The results of these experiments are discussed to determine the possibility of pre-strained strain gauges as haptic feedback sensors in soft robotics.
