Embedded TCP and SMA Actuators for Use in Flexible Structures of Bioinspired Robots and Humanoids
Soft robots consist of elastomeric materials, compliant actuators, and sensors that enable them to be used for numerous applications due to their flexibility, lightweight, and many degrees of freedom. Many actuators such as pneumatic actuators and servomotors introduce many design constraints due to their size, weight, and cost. Moreover, vibration and noise are undesired attributes that preclude the use of the robot. Smart materials play a vital role in the field of soft robotics since they can be used as sensors and actuators. This thesis presents the design and characterization of three robotic structures that are actuated by twisted and coiled polymer (TCP) muscles and shape memory alloys (SMA). First, a soft silicone skin embedded with TCP muscles that shows two unique modes of actuation is presented. The two actuation modes (undulatory and bending) depend on the muscle placement, skin thickness, applied voltage, and actuation time. Second, a humanoid head actuated using fully embedded TCP muscles featuring basic facial expressions, head nodding and jaw movement is presented. Third, an underwater jellyfish-like robot actuated by SMA muscles is developed. Several studies for the bell segment actuation were conducted to determine the influence of power input, bell geometry, and number of spring steels embedded within the elastomer. Studying these different application domains experimentally plays an important role in gaining new knowledge on design, fabrication, and performance of smart materials and soft robots.