  Nowadays an accurate modeling of the system to be controlled is essential for
reliable autopilot. This paper presents a non-linear model of the autonomous
underwater vehicle 'CWolf'. Matrices and the corresponding coefficients
generate a parameterized representation for added mass, Coriolis and
centripetal forces, damping, gravity and buoyancy, using the equations of
motion, for all six degrees of freedom. The determination of actuator behaviour
by surge tests allows the conversion of propeller revolutions to the respective
forces and moments. Based on geometric approximations, the coefficients of the
model can be specified by optimization algorithms in 'open loop' sea trials.
The realistic model is the basis for the subsequent design of the autopilot.
The reference variables used in the four decoupled adaptive PID controllers for
surge, heading, pitch and heave are provided a 'Line of Sight' - guidance
system. A constraint criteria optimization determines the required controller
parameters. The verification by 'closed loop' sea trials ensures the results.
