Loss of stability of guidance and control laws for autonomous vehicles

The problem of dynamic loss of stability of straight-line motion of a heading autopilot coupled with pursuit or proportional navigation guidance laws for an autonomous underwatervehicle is considered. The controller and navigator gain selections and the navigator lookahead distance serve as the main bifurcation parameters. Hopf-bifurcation-theory techniques are used in order to establish stability of the resulting periodic solutions after the initial loss of stability of straight-line motion. Numerical integrations support the analytical predictions. Compari- sons between different guidance schemes are made and guidelines for safer and more accurate vehicle operations are provided.