3D PRINTED FLEXIBLE SENSORS AND SOFT PNEUMATIC ACTUATORS WITH EMBEDDED DIELECTRIC ELECTROACTIVE POLYMERS FOR GRIPPING AND REHABILITATION APPLICATIONS

The present work expands the state of the art in the design of soft actuators and flexible sensors manufactured through fused deposition modelling (FDM) and direct ink writing (DIW). The first design consisted of flexible sensors for rehabilitation. Three different designs were tested and compared according to their sensitivity and accuracy. The flexible sensor successfully responded to deformation by changing its resistance. The first design of soft actuator was the Closed Dual Pneumatic Bellow Actuator. The soft actuator was manufactured using FDM and included an inner chamber in which the input air flows through and produces the actuation. The actuator also included dielectric electroactive polymer (DEAP) that showed response to pressure between the actuator and the object to be grasped. The electrodes of the DEAP were manufactured using commercial conductive TPU. A second soft actuator was designed with a circular shape and embedded DEAP. The electrodes in the DEAP consisted of conductive carbon grease. Previous tests were performed to assess the functionality of a DEAP structure using conductive carbon grease. The DEAP showed an increase in capacitance as pressure was applied on one side of the structure parallel to the electrodes and computational simulations validated such response. Future work using the sensors and actuators presented includes the implementation of a closed-loop system to the soft actuators, using the readouts of the sensors to adjust the input pressure and apply precise pressure on objects. The flexible sensor for rehabilitation has the potential to be implemented in each of the fingers of the hand and use the data to characterize the movement of the hand under different configurations providing feedback to patients in task-oriented therapy.