In this paper, a fault-tolerant control (FTC) method for robotic manipulators is proposed to deal with the lumped uncertainties and faults in case of lacking tachometer sensors in the system. First, the third-order sliding mode (TOSM) observer is performed to approximate system velocities and the lumped uncertainties and faults. This observer provides estimation information with high precision, low chattering phenomenon, and finite-time convergence. Then, an FTC method is proposed based on a non-singular fast terminal switching function and the TOSM observer. This combination provides robust features in dealing with the lumped uncertainties and faults, increases the control performance, reduces chattering phenomenon, and guarantees fast finite-time convergence. Especially, this paper considers both two periods of time, in which before and after the convergence process takes place. The stability and the finite-time convergence of the proposed controller-observer technique is demonstrated using the Lyapunov theory. Finally, to verify the effectiveness of the proposed controller-observer technique, computer simulation on a serial two-link robotic manipulator is performed.

中文翻译：

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使用非奇异快速终端滑模控制和三阶滑模观测器的机器人有限时容错控制

本文提出了一种用于机器人操纵器的容错控制（FTC）方法，以解决系统中缺少转速表传感器的情况下总的不确定性和故障。首先，执行三阶滑模（TOSM）观测器以近似系统速度以及不确定性和故障的总和。该观察者提供具有高精度，低颤动现象和有限时间收敛的估计信息。然后，提出了一种基于非奇异快速终端切换功能和TOSM观测器的FTC方法。这种组合提供了强大的功能来处理集中的不确定性和故障，提高了控制性能，减少了颤振现象，并保证了快速的有限时间收敛。特别是，本文同时考虑了两个时间段，在收敛过程之前和之后进行。利用李雅普诺夫理论证明了所提出的控制器－观测器技术的稳定性和有限时间收敛性。最后，为了验证所提出的控制器-观察器技术的有效性，对串行双链接机器人操纵器进行了计算机仿真。