基于变化率模型的滑模变结构控制及应用

Sliding Mode Variable Structure Control Based on Change Rate Model and Application

滑模变结构控制具有响应快速、对参数及外界扰动不灵敏的特点。具有代表性的趋近律等设计方法大都需要对象的数学模型,工程应用受到一定限制。对此,提出一种基于被控变量变化率模型的滑模变结构控制方法,以系统偏差和偏差变化率为状态变量建立切换函数,根据变化率模型设计等效控制作用,根据切换函数与系统正反特性设计切换控制作用,同时对滑模变结构控制算法进行改进以减弱抖振。该控制策略无需对象的严格数学模型,工程上容易实现。通过经验测试法建立了聚丙烯反应釜仿真对象温度的变化率模型,基于该模型设计的滑模变结构控制取得了优良的控制效果,验证了控制方案的可行性与有效性。

Sliding mode variable structure control has the feature of quick response,insensitive to parameters and external disturbance.However,most methods including the typical reaching law approach need mathematical model,so its engineering application is limited.A sliding mode control based on change rate model is proposed.System deviation and change rate of deviation are chosen as state variables to design switching function.Equivalent control action is designed based on the model,and variable switching control action is designed based on the switching function and system characteristic.Some improvements are made to alleviate the chattering.This control strategy is easy to be realized in engineering with no need of strict mathematical model.Through empirical method,the temperature change rate model of polypropylene CSTR is presented,and based on the model variable structure control scheme is presented. The control scheme has high performance,which demonstrates the validity and usefulness of the proposed method.