Adaptive robust control of linear motors with dynamic friction compensation using modified LuGre model
Adaptive robust control of linear motors with dynamic friction compensation using modified LuGre model
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DOI：
10.1016/j.automatica.2009.09.007
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发表时间：
2009-12-01
期刊：
影响因子：
6.4
通讯作者：
Chen, Zheng
中科院分区：
文献类型：
--
作者：
Lu, Lu;Yao, Bin;Chen, Zheng
LuGre模型在动态摩擦建模和补偿中有着广泛的应用。然而，在本文所研究的直线电机驱动系统等运动速度范围较大的系统中，它的应用存在一定的实际困难。本文首先详细介绍了基于LuGre模型的动态摩擦补偿的数字化实现问题。然后提出了一个改进的模型来克服这些缺点。该模型在低速时等价于LuGre模型，在高速时等价于静摩擦模型，两者之间存在连续过渡。然后构造了一种基于不连续投影的自适应鲁棒控制器(ARC)，该控制器显式地结合了所提出的改进的动态摩擦模型以实现更好的摩擦补偿。建立了非线性观测器来估计动态摩擦模型的不可测内部状态。利用在线参数自适应来减小各种参数不确定性的影响，同时综合一定的鲁棒控制律来有效地处理各种建模不确定性，以保证系统的鲁棒性能。并在直线电机驱动的工业门架系统上实现了该控制器，以及采用传统静摩擦补偿和LuGre模型补偿的控制器。大量的对比实验结果揭示了在高速实验中使用传统的LuGre模型进行动态摩擦补偿时的不稳定性，以及使用改进的动态摩擦模型时跟踪精度的提高。实验结果验证了该方法在实际应用中的有效性。(C)2009爱思唯尔有限公司。保留所有权利。
LuGre model has been widely used in dynamic friction modeling and compensation. However, there are some practical difficulties when applying it to systems experiencing large range of motion speeds such as, the linear motor drive system studied in the article. This article first details the digital implementation problems of the LuGre model based dynamic friction compensation. A modified model is then presented to overcome those shortcomings. The proposed model is equivalent to LuGre model at low speed, and the static friction model at high speed, with a continuous transition between them. A discontinuous projection based adaptive robust controller (ARC) is then constructed, which explicitly incorporates the proposed modified dynamic friction model for a better friction compensation. Nonlinear observers are built to estimate the unmeasurable internal state of the dynamic friction model. On-line parameter adaptation is utilized to reduce the effect of various parametric uncertainties, while certain robust control laws are synthesized to effectively handle various modeling uncertainties for a guaranteed robust performance. The proposed controller is also implemented on a linear motor driven industrial gantry system, along with controllers with the traditional static friction compensation and LuGre model compensation. Extensive comparative experimental results have been obtained, revealing the instability when using the traditional LuGre model for dynamic friction compensation at high speed experiments and the improved tracking accuracy when using the proposed modified dynamic friction model. The results validate the effectiveness of the proposed approach in practical applications. (C) 2009 Elsevier Ltd. All rights reserved.