Abstract
Most actuation systems in a variety of industries rely on rotary actuators to generate mechanical work. In this context, it becomes particularly useful to be able to measure torque, for diagnostic purposes as well as closed-loop control. However, current torque-measuring solutions are significantly more expensive than their linear force-measuring counterparts. Moreover, torque sensors are usually difficult to couple or embed into existing systems since they are often attached to rotary shafts. For these reasons, torque sensors are not widely used in automotive, construction, or agricultural industries. As additive manufacturing technologies make their way into conventional manufacturing processes, an opportunity arises to design torque-measurement devices that take advantage of these new manufacturing processes by being fully integrated into other components. In this work, resistance and capacitance-based torque sensors were designed and tested. The sensors rely on the combination of two or more printed materials with dissimilar electrical properties, which are able to electrically respond to external physical stimuli. Conductive Thermoplastic Polyurethane (e-TPU) is used to create flexible conductive structures, while ultra-flexible dielectric material (X60) is used to create capacitors of variable geometry. These sensors can easily be embedded into other soft and flexible parts, such as automotive motor mounts, providing a higher degree of control and reliability in an otherwise stagnant design.
