250763.fig.001a
(a)
250763.fig.001b
(b)
250763.fig.001c
(c)
250763.fig.001d
(d)
Figure 1: (a) Signals 𝑥 1 , 𝑥 2 , (b) Signals 𝑦 1 , 𝑦 2 , (c) Signals 𝑧 1 , 𝑧 2 , and (d) Error system.