Stability-Guaranteed Variable Impedance Control of Robots Based on Approximate Dynamic Inversion
Stability-Guaranteed Variable Impedance Control of Robots Based on Approximate Dynamic Inversion
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DOI：
10.1109/tsmc.2019.2930582
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发表时间：
2019-08
期刊：
影响因子：
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通讯作者：
Tairen Sun;Liang Peng;L. Cheng;Z. Hou;Yongping Pan
中科院分区：
文献类型：
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作者：
Tairen Sun;Liang Peng;L. Cheng;Z. Hou;Yongping Pan
变阻抗控制在提高机器人与环境交互的顺应性、安全性和效率方面具有重要的应用价值。但现有的变阻抗控制器在稳定性保障方面存在不足。针对具有建模不确定性的机器人，提出了一种基于近似动态反演（ADI）的保稳定变阻抗控制方法。为了保证所期望的变阻抗动力学的指数稳定性，对变阻抗曲线提出了新的约束条件。设计了一种基于人工智能的阻抗控制律，通过对变阻抗误差的收敛来实现期望的变阻抗动态。基于扩展的Tikhonovs定理，证明了闭环控制系统具有半全局实际指数稳定性。所提出的阻抗控制器可以以PID形式实现，具有结构简单、易于实现和控制稳定性保证等优点。以五杆并联机器人为例，说明了该变阻抗控制器的有效性。
Variable impedance control has been considered as one of the most important compliant control approaches for its abilities in improving compliance, safety, and efficiency in robot–environment interaction. However, existing variable impedance controllers have deficits in stability guarantee. This article proposes a stability-guaranteed variable impedance control approach for robots with modeling uncertainties based on approximate dynamic inversion (ADI). Novel constraints on variable impedance profiles are given to guarantee the exponential stability of the desired variable impedance dynamics. An ADI-based impedance control law is designed to achieve the desired variable impedance dynamics through the convergence of a variable impedance error. Based on the extended Tikhonovs theorem, it is proven that the closed-loop control system has semiglobal practical exponential stability. The proposed impedance controller can be implemented in a PID form and is appealing for its simple structure, easy implementation, and control stability guarantee. The effectiveness of the proposed variable impedance controller is illustrated by an illustrative example taken on a five-bar parallel robot.