Model free based finite time fault‐tolerant control of robot manipulators subject to disturbances and input saturation

Abstract

This article proposed a model free based finite time fault-tolerant control (FTC) method of robot manipulators subject to unknown disturbances, input saturation, and actuator faults. First, an accuracy-driven integral terminal sliding mode surface (ADITSMS) was constructed, and the finite-time convergence and the parametric analysis were investigated. Second, based on the proposed ADITSMS, a double-loop control framework which consists of the position loop and velocity loop was proposed, and the finite time command filtered algorithm was utilized to estimate the derivative of the virtual control law of the position loop, thus a novel finite-time robust adaptive FTC was proposed. Third, to eliminate the negative effects of the faults and disturbances and implement model free control, the uncertainty and disturbance estimation is designed, and a novel adaptive algorithm is developed to suppress the estimation error whose upper bound or derivative was not required. Meanwhile, an auxiliary system is constructed to deal with the input saturation. The proposed controller possess the superiorities of model free nature and global finite time convergence property. Finally, numerical simulations and comparison studies were conducted to demonstrate the effectiveness of the proposed controller.

Practical preset time fault‐tolerant control of uncertain Euler–Lagrange systems with input saturation and guaranteed performance

“…Therefore, it is necessary to take actuator faults along with the input saturation into account in the process of controller design. In References 21–24, actuator faults and input saturation are considered simultaneously, where the adverse effects caused by input saturation and actuator faults are compensated separately based on different compensation strategies, so that the complexity of the controller is relatively high.…”

“…Besides, the tracking error can converge to an asymmetric region using the proposed strategy. Consequently, the proposed method has a wider range of application scenarios. Different from the complex compensation strategies in Reference 21–24, the Nussbaum gain technology applied in this article can compensate for the adverse effects of both actuator faults and input saturation simultaneously, thus eliminating the need to design different compensation strategies separately, which reduces the complexity of controller.…”

Fault-Tolerant Cooperative Control of Multiple Uncertain Euler-Lagrange Systems with an Uncertain Leader

“…In [21], a decentralized faulttolerant controller for robot manipulators was proposed by combining terminal sliding modes and a super-twist algorithm to minimize chattering and expedite convergence. In [22], a sliding mode surface for integral terminal was carefully developed, resulting in the development of a model-free finite-time resilient adaptive fault-tolerant control for robot manipulators, demonstrating advantages in global finite-time convergence. Faulttolerant cooperative control stands out as a leading control technology ensuring consistent and optimal performance of dynamic systems despite component faults [18,19,23].…”

Model-free sliding mode prescribed performance control of robotic manipulator based on new reaching law

“…Besides, it takes long time that the approximate values converge to the actual real values during weight training by estimation rules. Model-free control method 38,39 where controlled system only contains the input term and unknown term is gradually introduced to solve aforementioned drawbacks.…”