Robust Synchronization of Fractional-Order Hyperchaotic Systems Subjected to Input Nonlinearity and Unmatched External Perturbations

Figure 5

Error states of controlled drive and response systems: (a) error state of 𝑒₁; (b) error state of 𝑒₂; (c) error state of 𝑒₃; (d) error state of 𝑒₄.

(a)

(b)

(c)

(d)