Model-based open loop control of a multigait legged underwater robot

In this paper a model-based open loop control of SILVER, a multigait legged underwater vehicle for the benthic zone exploration, is presented. The contributions of underwater environment are taken into account by resorting to a recently introduced fundamental model of monopedal underwater hopping locomotion on which the tuning of a completely open loop control algorithm for dynamic gaits is based. The design of the robot and the control algorithm of each gait are presented along with experimental results which demonstrate on-spot static and dynamic rotation, and forward locomotion by crawling, walking and hopping. Moreover, for the first time the behavior of multi-legged underwater robots is grounded to the fundamental monopedal model. SILVER is the first underwater legged robot capable of performing dynamic self-stabilizing hopping gaits together with static gaits and precise foot placement. Thanks to its unique features the category of underwater legged robots has the potential to be a very versatile and valuable alternative to the existing technology for the exploration of the seabed.