考虑关节摩擦的3-UPS/PU并联机构模糊自适应滑模控制  

Adaptive Fuzzy Sliding Mode Control of 3-UPS/PU Parallel Mechanisms Including Joint Frictions

作　　者：张达[1] 原大宁[1] 刘宏昭[1] 

机构地区：[1]西安理工大学机械与精密仪器工程学院,西安710048

出　　处：《中国机械工程》2017年第4期391-397,403,共8页China Mechanical Engineering

基　　金：国家自然科学基金资助项目(51275404);陕西高校省级重点实验室科研项目(2010JS080)

摘　　要：为克服3-UPS/PU并联机构关节摩擦力突变现象带来的跟踪畸变问题,设计了一种模糊自适应滑模控制方法。首先在机构动平台工作空间内建立该机构的整体动力学模型。针对切换型滑模控制驱动力抖振以及自适应滑模控制(ASMC)对摩擦突变较敏感的不足,提出一种模糊自适应滑模控制(FASMC)方法,该方法以自适应理论为基础,可以在线估计包括摩擦在内的系统模型不确定项,自适应增益通过模糊逻辑系统实现了动态调整,相比ASMC可以更准确地逼近摩擦的变化情况,从而更有效地抑制摩擦力突变影响,增强了系统鲁棒性。由于无需依赖具体的摩擦模型以及简单的控制结构,FASMC适用于并联机构这类复杂不确定系统。仿真结果显示,所采取的控制方法能有效估计并克服机构摩擦干扰,提高了机构的控制精度,而且驱动力没有出现抖振现象。In order to overcome the tracking aberration caused by joint friction mutations of a 3-UPS/PU parallel mechanism,a fuzzy adaptive sliding mode control was proposed.Firstly,dynamics model of the mechanisms with respect to platform workspaces was constructed.Considering the traditional sliding mode control（SMC）had deficiency that driving force chattering and adaptive SMC（ASMC）was sensitive to friction mutations,a fuzzy ASMC（FASMC）was proposed,which might estimate and compensate the model uncertainty including joint friction based on adaptive theory.And the adaptive gains were adjusted dynamically by means of fuzzy logic system.Consequently,FASMC may estimate the frictions more accurately and restrain friction mutations more efficiently compared with ASMC,and the system robustness was improved.This control method did not need to rely on the friction model and had a simple structure,therefore it was suitable for complicated and uncertain systems such as parallel mechanisms.The simulation results show that the proposed control method may estimate and overcome the friction disturbances efficiently and improve the control precision,the chattering problems from driving torque are also resolved.

关 键 词：3-UPS/PU并联机构 关节摩擦 动力学模型 自适应滑模 模糊逻辑 

分 类 号：TH212[机械工程—机械制造及自动化] TH213.3