  An intelligent control strategy is proposed to eliminate the actuator
saturation problem that exists in the trajectory tracking process of unmanned
underwater vehicles (UUV). The control strategy consists of two parts: for the
kinematic modeling part, a fuzzy logic-refined backstepping control is
developed to achieve control velocities within acceptable ranges and errors of
small fluctuations; on the basis of the velocities deducted by the improved
kinematic control, the sliding mode control (SMC) is introduced in the dynamic
modeling to obtain corresponding torques and forces that should be applied to
the vehicle body. With the control velocities computed by the kinematic model
and applied forces derived by the dynamic model, the robustness and accuracy of
the UUV trajectory without actuator saturation can be achieved.
