Straight-Line Tracking with EDPU. In this section, the robust containment control strategy in the presence of the disturbances is also examined.
It is clearlyseen from Figures 5 and 9 that the proposed controller yields slightly worse performance than the previous section due to the EDPU. However, the tracking errors are bounded, which means that the tracking errors for each follower are GUUB as proved in Theorem 20.
This experiment validates the control strategy without considering the EDPU. The initial follower states [X.sub.i] = ([x.sub.i]; [y.sub.i]; [[psi].sub.i]; [u.sub.i]; [v.sub.i]; [r.sub.i]) are [X.sub.1] = (-14.5; -5; [pi]/3; 0.01; 0.02; 0); [X.sub.2] = (-12; -7; [pi]/4; 0.02; 0.012; 0); [X.sub.3] = (-8; -6; [pi]/6; 0.02; 0.03; 0); [X.sub.4] = (-6; -7; [pi]/3; 0.01; 0.01; 0); [X.sub.5] = (-4; -5; [pi]/2.5; 0; 0.015; 0).
Curve Tracking with EDPU. In this section, the simulation experiments are presented, which concern the robustness properties of the containment control law to the EDPU.
As seen from Figures 16 and 17, the containment control laws can force the followers to converge into the triangular region in the presence of the EDPU, and the norms of the tracking errors are all less than 0.75 m.