Volume 23 Issue 01 - Publication Date: 1 January 2004
Motion Planning and Control of a Swimming Machine
Saroj Saimek and Perry Y. Li Department of Mechanical Engineering, University of Minnesota, 111 Church St. SE, Minneapolis MN 55455, USA

We propose a practical maneuvering control strategy for an aquatic vehicle (AV) that uses an oscillating foil as a propulsor. The challenge of this problem lies in the need to consider the hydrodynamic interaction as well as the underactuated and non-minimum phase natures of the AV system. The control task is decomposed into the off-line step of motion planning and the on-line step of feedback tracking. Optimal control techniques are used to compute a repertoire of time-scalable and concatenable motion primitives. The complete motion plan is obtained by concatenating time-scaled copies of the primitives. The computed optimal motion plans are regulated by a controller that consists of a cascade of linear quadratic regulator, input–output feedback linearization and sliding mode control. Time-varying linear quadratic controllers can also be time-scaled and concatenated. Therefore, they can be computed beforehand. The proposed strategy has been experimentally validated for both constrained longitudinal only maneuvers and unconstrained longitudinal/lateral maneuvers.

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