This paper investigates the use of an adaptive system to stabilize a launch vehicle with sloshable fuel. The adaptive system utilizes a laser sensor to measure fluid displacement in the tank, a recursive-least-squares estimator to estimate the natural frequency of the sloshing fuel, and a linear filter which stabilizes the unstable fuel slosh using the frequency estimate. The method was successful for a single slosh-pendulum model and requires no tank baffles or partitions.
James M. Adler,
Michael S. Lee,
John D. Saugen,
"Adaptive control of propellant slosh for launch vehicles", Proc. SPIE 1480, Sensors and Sensor Integration, (1 July 1991); doi: 10.1117/12.46489; https://doi.org/10.1117/12.46489