Distributed actuation and sensing are important tools in the biological arsenal for achieving robust locomotion and manipulation. This proposal investigates a form of distributed actuation based on the "water hammer" effect. Intuitively, this is the transfer of momentum from the moving water to the valve as the valve suddenly closes. This transfer results in three separate effects. The momentum transfer to the valve imparts a push to the robot. The transfer to the hose has not been well studied for compliant hoses, but appears to reduce friction of the tether, temporarily freeing it and propulsing the tether forward. Finally, a travelling pressure wave is established that has not been well studied, either. Preliminary results have shown that the combination of these effects allows a tethered robot to extend its operational sphere well beyond conditions where a conventional tether would fail. The high-risk, high-reward research in this exploratory proposal aims to achieve two goals: demonstrate the effectiveness of water hammer actuation for endoscopic applications and to develop a finite element model of the reverse pressure wave in compliant hoses. This model will lead the way toward harnessing the unexplained phenomena mentioned above, making the general application of these principles more achievable.
