Model-free fractional-order adaptive back-stepping prescribed performance control for wearable exoskeletons

Autor: Yanli Geng, Jie Wang, Jianjun Sun, Peng Yang
Rok vydání: 2021
Předmět:
Zdroj: International Journal of Intelligent Robotics and Applications. 5:590-605
ISSN: 2366-598X
2366-5971
DOI: 10.1007/s41315-021-00166-3
Popis: In this paper, we present a novel model-free fractional-order adaptive back-stepping control scheme for the wearable exoskeletons with constraints on the joint angle tracking errors. Firstly, the ultra-local model based intelligent proportion integration differentiation (iPID) control is combined with time delay estimation (TDE) to realize a model-free feature, and the precise modeling process can be abandoned. Then, an adaptive back-stepping controller is introduced to handle with the estimation errors of TDE. Control behavior is greatly improved by introducing the fractional-order calculus and prescribed performance is guaranteed by the log-type barrier Lyapunov function implemented in the back-stepping approach. In addition, system stability is verified via Lyapunov stability theory. Finally, to demonstrate the effectiveness of the proposed control scheme, a 5 DOF wearable exoskeleton virtual prototype is designed in SolidWorks and transferred to MATLAB as the controlled plant for visualization simulation. Simulation results show the improved performance between the proposed method and comparison methods.
Databáze: OpenAIRE
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