Glider control: A close look into the current glider controller structure and future developments

Simplicity of operation, extreme endurance and stealth are some of the principal advantages of autonomous underwater gliders. These advantages come at the expense of a minimalist approach in the sense of actuation and permissible power consumption. Also by nature the gliders are highly dependent on their operational environment, notably currents and density gradients. A control system that is able to cope with this challenging dynamic environment and the actuation and sensing constraints has to be robust with respect to environmental uncertainties and at the same time it has to be optimal in the sense of power consumption and accuracy. In this paper we look at the existing controller structure and show possibilities for improvements within the framework of the available sensor information. We summarize the existing controller structure and show results from recent field-tests of Slocum gliders in the Gulf of Mexico that demonstrate the potential for improvements in the sense of reduced power consumption associated with actuation and decreased response time enabling shallow water operations.