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Self-motion effects on hydrodynamic pressure sensing: part I. forward-backward motion.
Otar Akanyeti1, Lily D Chambers, Jaas Ježov
1The Whitney Laboratory for Marine Science, University of Florida, FL 32080, USA. otarakanyeti@yahoo.com
Bioinspiration & Biomimetics
|March 7, 2013
Summary
Researchers developed a pressure sensing model for underwater vehicles to distinguish external flows from self-motion. This bimodal strategy uses pressure gradients for external events and absolute pressure for speed measurement.
Area of Science:
- Fluid dynamics
- Robotics
- Sensor technology
Background:
- Underwater locomotion faces challenges in distinguishing external flow information from self-generated signals due to complex fluid-structure interactions.
- Sensing and motion are interdependent, with self-generated flows altering external hydrodynamic signals, a poorly understood phenomenon.
Purpose of the Study:
- To investigate self-generated flow signals in underwater locomotion using onboard pressure sensors.
- To develop a model for estimating surface pressure based on craft velocity and acceleration.
- To explore a bimodal sensing strategy for underwater vehicles.
Main Methods:
- Utilized onboard pressure sensors on a fusiform-shaped craft to measure pressure profiles during harmonic forward and backward motion.
- Developed a second-order polynomial model correlating craft velocity and acceleration with surface pressure.
- Analyzed pressure intensity variations in temporal and spatial domains relative to craft movement.
Main Results:
- A model was established to estimate surface pressure up to one body length per second (L/s), incorporating velocity and acceleration.
- At low velocities (<0.2 L/s), pressure signals were more sensitive to acceleration; inertial effects decreased with increasing velocity.
- Foremost sensors showed higher sensitivity to craft movement than side sensors, with peak pressures up to 300 Pa at 1 L/s.
Conclusions:
- Distributed pressure sensing offers a bimodal strategy: one mode for external hydrodynamic events (using pressure gradients) and another for self-motion monitoring (as a speedometer).
- The study demonstrates that pressure sensing can effectively measure a craft's velocity, aiding in navigation and environmental perception.
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