CyberDiver: An untethered robotic impactor for water-entry experiments

This is the authors' abstract. We don't add key points for this paper.

We present the CyberDiver, an untethered robotic impactor capable of actively modulating the fluid physics during high-speed water entry. First, we utilize the CyberDiver to extend our understanding of the water entry of passively flexible systems, designing a high-bandwidth controller that enables the CyberDiver to operate as a cyber–physical system that permits an arbitrary programmable structural coupling to be experimentally tested. Onboard sensors record the body acceleration during impact and reveal that the introduction of damping or a nonlinear force-versus-displacement structural law can significantly reduce impact loading as compared to a linear elastic case, with implications for damage mitigation in aerospace and naval applications. Next, by operating the CyberDiver in a displacement control mode, we demonstrate that the splash size can be dramatically altered depending on the parameters of an active maneuver, laying a groundwork for better understanding the techniques of human competitive divers. • Developed an untethered cyber–physical robotic impactor for water-entry experiments. • Structural damping or nonlinear compliance can reduce impact loading. • Splash size can be altered via an active maneuver at the moment of impact.