机械系统中摩擦模型的研究进展

AN OVERVIEW OF FRICTION MODELS IN MECHANICAL SYSTEMS

摩擦现象在机械系统中的作用日益突出,合理地解决机械系统中摩擦环节尤其是非线性摩擦环节的制约问题已成为当前研究的重点.由于摩擦的复杂性,很难从机理上获得其准确唯一的数学模型,迄今已提出的摩擦模型有数十种.鉴于目前机械系统中摩擦建模的发展状况,首先描述了几种重要的摩擦现象,如库仑摩擦、黏性摩擦、Stribeck效应、预滑动摩擦、可变的静态摩擦力和摩擦记忆效应等.其次,系统地介绍了几种较为重要的、常用的摩擦模型,包括6种静态摩擦模型和7种动态摩擦模型,并对每一种模型的构成,特点和适用范围等进行了较为详细地论述.比较而言,静态摩擦模型结构简单,参数辨识容易,但是无法描述摩擦的动态特性,动态摩擦模型能够比较全面的描述摩擦现象,但结构复杂,参数辨识难度较大.再次,简要概述了摩擦建模对机械系统动力学行为的影响,以及在高精度定位系统的控制中的作用.最后,针对当前机械系统中摩擦建模方面存在的一些不足提出了几点展望.为今后摩擦模型的选用和新摩擦模型的建立提供了参考.

The friction in mechanical systems plays an increasingly prominent role. It is important to reduce friction in mechanical systems, especially the nonlinear friction. Because of its complicated nature, it is very difficult for a single model to account for various mechanisms of friction, and dozens of friction models have been put forward so far. With respect to the development of the friction modeling in mechanical systems, some important friction phenomena are first described in this paper, such as Coulomb friction, viscous friction, Stribeck friction, presliding displacement, varying static force and friction lag, etc. Next, a few important friction models in common use are discussed, including six static and seven dynamic friction models. The forms, characteristics and applicability of these models are discussed in detail. The forms and the parameter identification of the static friction models are simple and easy, but they cannot be used to simulate the dynamic characteristics of friction. Comparatively, the dynamic friction models can describe the friction more completely, with their complicated forms, which makes it difficult to identify related parameters. Then, the influence of friction modeling on the mechanical system dynamics is briefly discussed as well as the applications of friction models to the control of high precision mechanical systems. Lastly, several problems to be further studied are pointed out. This paper provides some guidance in the selection of friction models in applications.