Development of a Versatile Test-Bed "Twin-Burger" toward Realization of Intelligent Behaviors of Autonomous Underwater Vehicles


IV. MOTION CONTROL

In order that the Twin-Burger behaves according to commanded missions, appropriate swimming capability should be given to the vehicle by introducing a motion control methodology. It is difficult to get precise equations of motion of the Twin-Burger from hydrodynamic model tests, such as PMM (Planar Motion Mechanism) tests, because the configuration of the vehicle is relatively complex and expected to be modified frequently, and the nonlinearity should be considered when the vehicle cruises at low speed.

Here, a sliding control method, which is a robust control strategy to model uncertainty, nonlinear dynamics and unknown disturbances, establish for trajectory control of underwater vehicles by Yoerger and Slotine[8] is applied to the Twin-Burger vehicle. Since the nonlinear cross coupling terms which appear in the Twin-Burger's equations of motion can be taken as parameter uncertainties in this method, an independent sliding controllers can be designed for each mode of four-degrees-of-freedom motion of the vehicle, that is, surging, swaying, heaving and yawing.


Last modified: Thur July 6 1995