Experimental validation of disturbance observer-based adaptive terminal sliding mode control subject to control input limitations for SISO and MIMO systems

Nowadays, advances in different fields of technology have increased demands for reliable controllers. Un-certainty, disturbances, and limitations in control inputs are inevitable with most systems. Hence, consid-ering them in designing a practical controller seems indispensable to any system. We propose an adap-tive, robust, and finite time control technique for both multi-input multi-output (MIMO) and single-input single-output (SISO) systems. In the design of the proposed control technique, due to the undeniable ex-istence of disturbances and control input limitations, their effects are fully taken to account. On the basis of a finite time sliding mode strategy, controllers and disturbance observers are designed. Then, the sta-bility and finite time convergence of the proposed control scheme and disturbance observer are proven via the Lyapunov stability theory. Eventually, to investigate the performance of the proposed method in real-world applications, a hardware-in-the-loop (HIL) test is carried out for the proposed control scheme. Through numerical simulation and the results of the HIL test, the high-effective performance of the pro-posed controller for uncertain chaotic systems was demonstrated. Moreover, the results of the HIL test showed that by implementing continuous functions in the design of the controller, chattering, which has detrimental effects on systems, will be reduced in practical applications. Numerical simulations and the results of the HIL test bench for the modified controller clearly confirmed the effective performance of the offered control technique for practical systems. Thereby applying the proposed control technique for complex nonlinear systems subject to control input limitations, disturbances, and time-varying uncertain-ties will be useful.(c) 2021 European Control Association. Published by Elsevier Ltd. All rights reserved.