Research on Vibration Reduction Method for an Autonomous Ocean Turbulence Measurement Platform

As a mobile autonomous ocean observation platform, Autonomous Underwater Vehicle (AUV) has the advantage of long endurance and large range, being free from sea condition. The microstructure of velocity and temperature of horizontal and vertical profiles can be obtained with a selfdeveloped AUV, which carries two shear probes, and an FP07 thermistor mounted on a sting at the forward end of the vehicle. However, since the shear probes are essentially transverse force sensors, they are sensitive to vibration noise, and any vibration of the AUV will show up as a spurious signal in the measured shear signal, which will reduce the lower resolution limit of dissipation rate of turbulent kinetic energy. Focusing on the vibration noise of AUV turbulence measurement platform, the work has presented a flexible connection vibration reduction method based on extension spring, and the vibration test has been carried out. By comparing and analyzing the time-frequency domain characteristics of vibration acceleration before and after vibration damping, the results show that the RMS and energy of vibration acceleration are significantly reduced, especially vibration above 54 Hz, whereupon the average damping efficiency is more than 70%, which verifies the validity of this method.