Brahmi Brahim, El Bojairami Ibrahim, Ahmed Tanvir, Swapnil Asif Al Zubayer, AssadUzZaman Mohammad, Wang Inga, McGonigle Erin, Rahman Mohammad Habibur
Mechanical Engineering Department, McGill University, Montreal, QC H3A 0G4, Canada.
Biomedical Engineering Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, USA.
Micromachines (Basel). 2021 May 21;12(6):597. doi: 10.3390/mi12060597.
The research presents a novel controller designed for robotic systems subject to nonlinear uncertain dynamics and external disturbances. The control scheme is based on the modified super-twisting method, input/output feedback linearization, and time delay approach. In addition, to minimize the chattering phenomenon and ensure fast convergence to the selected sliding surface, a new reaching law has been integrated with the control law. The control scheme aims to provide high performance and enhanced accuracy via limiting the effects brought by the presence of uncertain dynamics. Stability analysis of the closed-loop system was conducted using a powerful Lyapunov function, showing finite time convergence of the system's errors. Lastly, experiments shaping rehabilitation tasks, as performed by healthy subjects, demonstrated the controller's efficiency given its uncertain nonlinear dynamics and the external disturbances involved.
该研究提出了一种为受非线性不确定动力学和外部干扰影响的机器人系统设计的新型控制器。该控制方案基于改进的超扭曲方法、输入/输出反馈线性化和时间延迟方法。此外，为了最小化抖振现象并确保快速收敛到选定的滑动面，一种新的趋近律已与控制律相结合。该控制方案旨在通过限制不确定动力学的存在所带来的影响来提供高性能和更高的精度。使用强大的李雅普诺夫函数对闭环系统进行了稳定性分析，结果表明系统误差在有限时间内收敛。最后，由健康受试者执行的塑造康复任务的实验证明了该控制器在存在不确定非线性动力学和外部干扰情况下的有效性。
