Modeling for the performance of navigation, control and data post-processing of underwater gliders

Improving Resource Management for Unattended Observation of the Marginal Ice Zone Using Autonomous Underwater Gliders

“…Note that the two propulsive modes have different dependencies for efficiency, in particular, the thruster is most efficient at approximately 0.4 m s −1 , independent of depth band. In contrast, the efficiency of the buoyancy engine is dependent on depth band, and tends toward greater efficiency at pitch angles that are relatively shallow in comparison to conventional missions using 26 • pitch, which is consistent with polar curves estimated in the literature (Jenkins et al, 2003;Eichhorn et al, 2020). This figure suggests that a fairly broad thruster velocity envelope is more efficient than the buoyancy engine when operating within a narrow depth band.…”

“…Analytical models adapted from Jenkins et al (2003) and Scholz et al (2005) indicate that the through-water velocity contribution from the buoyancy engine can be expressed as a polynomial function of pitch angle φ, as shown in Equation ( 10). Detailed studies of Slocum Glider dynamics by Eichhorn et al (2020) indicate that transport cost is minimized at pitch angles of roughly 15 • when glider is driven by the buoyancy engine alone, although steeper angles yield higher horizontal speeds.…”

“…based on estimated efficiency and vehicle dynamic constraints, as described by Jenkins et al (2003), Cooney (2011), Eichhorn et al (2020), and Deutsch et al (2020. For now, depth band is assumed to be predetermined as well, based on the seafloor bathymetry, but the energy-optimal selection of glider depth band is revisited in section 2.5.…”

Identification of the Dynamics of Biofouled Underwater Gliders

“…using the parameters in Table III for the full VBD volume of 260 cm 3 , a water density of 1.027 kg/m 3 and ignoring the compressibility and thermal expansivity of the hull. Due to the low ratio of the estimated lift and drag coefficients, the polar plot presents higher minimum glide angle and glide angle for maximum horizontal speed than theoretical predictions in [3] and [4]. The discrepancy is likely to be due to the limited range of the θ −ż search space in the analysed deployments.…”

“…The study by Haldeman, et al [2] investigated the impact of biofouling during a deployment in the South Atlantic a posteriori. In [3], marine growth was observed to cause a drop in speed with time and an increase of 1 • in the angle of attack over a whole deployment for the same pitch command. Additionally, medium to severe biofouling levels can cause a decrease in the lift coefficient of up to 40% and an increase in the drag coefficient of 90% [4].…”