Model-free based fixed-time control for the uncertain wearable exoskeleton with preset performance

IF 5.4 2区计算机科学 Q1 AUTOMATION & CONTROL SYSTEMS

Control Engineering Practice Pub Date : 2024-07-19 DOI:10.1016/j.conengprac.2024.106011

引用次数: 0

Abstract

In this paper, the issue of fixed-time tracking control for the uncertain wearable exoskeleton with prescribed performance is addressed. To heighten the transient and steady-state performance of the exoskeleton system, a variable exponent coefficient-based fixed-time control approach is formulated. Benefiting from model-free control, the dynamic model of the exoskeleton is replaced by an ultra-local model that relies solely on input–output (IO) data. The tracking control problem of the exoskeleton system boils down to the boundedness problem of auxiliary variables via designing a nonlinear conversion function. The tracking errors converge to the origin in a fixed time and never violate predefined constraints. The mechanical design of the wearable exoskeleton is carried out by Solidworks, and the actual control system is meticulously constructed. The simulation and experimental outcomes confirm the efficacy and superiority of the presented control methodology.

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基于无模型的固定时间控制，用于具有预设性能的不确定可穿戴外骨骼

本文探讨了具有规定性能的不确定可穿戴外骨骼的固定时间跟踪控制问题。为了提高外骨骼系统的瞬态和稳态性能，本文提出了一种基于可变指数系数的固定时间控制方法。受益于无模型控制，外骨骼的动态模型被完全依赖于输入输出（IO）数据的超局部模型所取代。通过设计非线性转换函数，外骨骼系统的跟踪控制问题可归结为辅助变量的有界性问题。跟踪误差会在固定时间内收敛到原点，并且永远不会违反预定义的约束条件。可穿戴外骨骼的机械设计由 Solidworks 完成，实际控制系统也是精心构建的。仿真和实验结果证实了所提出的控制方法的有效性和优越性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Control Engineering Practice 工程技术-工程：电子与电气

CiteScore

9.20

自引率

12.20%

发文量

183

审稿时长

44 days

期刊介绍： Control Engineering Practice strives to meet the needs of industrial practitioners and industrially related academics and researchers. It publishes papers which illustrate the direct application of control theory and its supporting tools in all possible areas of automation. As a result, the journal only contains papers which can be considered to have made significant contributions to the application of advanced control techniques. It is normally expected that practical results should be included, but where simulation only studies are available, it is necessary to demonstrate that the simulation model is representative of a genuine application. Strictly theoretical papers will find a more appropriate home in Control Engineering Practice''s sister publication, Automatica. It is also expected that papers are innovative with respect to the state of the art and are sufficiently detailed for a reader to be able to duplicate the main results of the paper (supplementary material, including datasets, tables, code and any relevant interactive material can be made available and downloaded from the website). The benefits of the presented methods must be made very clear and the new techniques must be compared and contrasted with results obtained using existing methods. Moreover, a thorough analysis of failures that may happen in the design process and implementation can also be part of the paper. The scope of Control Engineering Practice matches the activities of IFAC. Papers demonstrating the contribution of automation and control in improving the performance, quality, productivity, sustainability, resource and energy efficiency, and the manageability of systems and processes for the benefit of mankind and are relevant to industrial practitioners are most welcome.