Region tracking control strategy with the guaranteed boundary on the position error distance for a nonlinear system

In some engineering missions, such as target searching, users focus more on the distance between the location of the system and the corresponding point on the desired trajectory, rather than control precision of each degree of freedom (DOF). For such scenario, a region tracking control strategy with the guaranteed boundary on the position error distance is proposed for a nonlinear system by introducing a special barrier Lyapunov function. From theoretical analysis, it is guaranteed that the distance of the position tracking error is always less than the user-defined boundary and the attitude tracking error on each DOF is always kept within the prescribed boundaries near zero under the proposed control strategy. Finally, simulation results on a nonlinear system with six DOFs verify the effectiveness of the proposed region tracking control strategy.