| dc.description.abstract | While lower limb exoskeletons for aboveground locomotion have been developed, few attempts have been made to develop an exoskeleton to augment human swimming. The design of exoskeletons for aboveground activities has benefitted greatly from experimental efforts characterizing the kinematics and kinetics of motion; however, simple data characterizing the biomechanics of human finned swimming are not readily available. This work first presents the design and evaluation of an off-board robotic finned swimming testbed and describes experiments conducted to explore the exoskeletal joint-space requirements to augment the finned swimming motion. These data are subsequently used to inform the design of a lower limb exoskeleton to augment human finned swimming. The exoskeleton is first used as an unmanned robotic swimmer to verify and extend the kinematic and kinetic findings previously projected with the off-board actuation testbed. Specifically, the testbed with off-board actuation was limited in torque and power, and also required modeling to estimate resulting thrust, whereas the setup with onboard and enhanced actuation was better able to explore the range of torque and power associated with human finned swimming, and was also equipped to directly measure thrust. The resulting data characterizes the torque, speed, and power requirements of the finned flutter kicking motion and associated thrust production, which is essential for the design of a lower limb exoskeleton to assist or augment the human finned swimming. The exoskeleton was then implemented and evaluated on human participants to assess the quality and extent of augmentation. Two control methodologies are presented. The first enables a human user to implicitly control hip joint torque and power delivery, and the second allows a human to swim with little to no effort. For each, experimental results that demonstrate effective joint-level torque amplification and substantial thrust augmentation are presented. This work constitutes the first demonstration of a lower limb exoskeleton to augment to the thrust production of a human swimmer. | |
