Hybrid super‐twisting fractional‐order terminal sliding mode control for rolling spherical robot

Abstract

The unmodeled parameters, uncertainties, chattering, and disturbances can be serious problems for a controller. These issues decrease the performance of the controller and make it difficult to have a satisfactory movement path as well. This paper presents a novel hybrid super‐twisting fractional‐order terminal sliding mode controller (HSTFOTSMC) for a rolling spherical robot (RSR) considering bounded model uncertainties for robot dynamics in presence of external disturbances and noise. The controller is based on a new adaptive fractional‐order terminal sliding surface. The stability of the proposed controller is proved by the Lyapunov theory, and then, it is tuned by a novel extended grey wolf optimizing (EGWO) algorithm to adjust the controller parameters, and assure to achieve the precise robot performance. The results of the optimized controller (EGWO‐HSTFOTSMC) are compared with the typical sliding mode controller (SMC), fractional‐order terminal sliding mode controller (FOTSMC), and super‐twisting fractional‐order terminal sliding mode controller (STFOTSMC), which demonstrate the effectiveness of the controller scheme. The controller implementation can potently eliminate the impacts of disturbances, noise, and uncertainties; meanwhile, it decreases the tracking error and increases the convergence speed of robot responses.

Fractional‐order sliding mode load following control via disturbance observer for modular high‐temperature gas‐cooled reactor system with disturbances

“…Similar to the previous analysis, it can be deduced from inequality () that the sliding variable $$$ {s}_{\rho } $$$ can converge to zero within a finite time. Moreover, the reactivity error $$$ {e}_{\rho } $$$ can globally exponentially converge to zero by means of Lyapunov finite‐time stability theory and fractional‐order terminal sliding mode control theory [37, 38].…”

Event-Triggered Sliding Mode Neural Network Controller Design for Heterogeneous Multi-Agent Systems

“…The sliding mode control scheme (SMCS) is superior to other control schemes in that it switches the modes of controllers with the current state [ 2 , 9 ]. There are various SMC strategies, such as terminal SMC [ 10 , 11 ], dynamic SMC [ 12 ] and adaptive SMC [ 13 ], and so on. SMC is widely used in practical engineering applications with excellent and robust performance [ 14 ], such as stochastic systems [ 15 ], robot MASs [ 16 ] and heterogeneous nonlinear MASs [ 17 ].…”

Fractional‐order sliding mode control for a novel magneto‐electro‐elastic microtube robot

“…There are a wide variety of robust tracking controllers for robotic applications [19] among which the sliding mode controller has been a well-known technique for uncertain systems [20,21]. Also, fractional controllers (compared to conventional ones) offer better performance, due to more tunable parameters [22,23]. A combination namely the "fractional order sliding mode controller (FOSMC)" has since been broadly used in order to achieve better robustness, while keeping the main benefits of the SMC [24,25].…”