Adaptive control realization for canonic Caputo fractional-order systems with actuator nonlinearity: application to mechatronic devices

Abstract

Nonlinearities, such as dead-zone, backlash, hysteresis, and saturation, are common in the mechanical and mechatronic systems' components and actuators. Hence, an effective control strategy should take into account such nonlinearities which, if unaccounted for, may cause serious response problems and might even result in system failure. Input saturation is one of the most common nonlinearities in practical control systems. So, this article introduces a novel adaptive variable structure control strategy for nonlinear Caputo fractional-order systems despite the saturating inputs. Owing to the complex nature of the fractional-order systems and lack of proper identification strategies for such systems, this research focuses on the canonic systems with complete unknown dynamics and even those with model uncertainties and external noise. Using mathematical stability theory and adaptive control strategy, a simple stable integral sliding mode control is proposed. The controller will be shown to be effective against actuator saturation as well as unknown characteristics and system uncertainties. Finally, two case studies, including a mechatronic device, are considered to illustrate the effectiveness and practicality of the proposed controller in the applications.

Internal synchronization using adaptive sliding mode

“…18,19 There can also be seen innumerable researches based on the systems like synchronization of identical/non-identical systems, different orders (called as Reduced/Increased order), and integer/fractional. [20][21][22][23][24] Numerous worthy researches have also been investigated based on applications of synchronization including security through multi-switching, compound, combination-combination synchronization. [25][26][27] So far, there are plenty of phenomenal works on chaos synchronization have been reported.…”

“…There are innumerable robust techniques have been developed based on the advantages over predecessor one in terms of stability, time response, low chattering, effects of modeling uncertainty and noise 18,19 . There can also be seen innumerable researches based on the systems like synchronization of identical/non‐identical systems, different orders (called as Reduced/Increased order), and integer/fractional 20–24 . Numerous worthy researches have also been investigated based on applications of synchronization including security through multi‐switching, compound, combination‐combination synchronization 25–27 …”