高阶非线性液压辊缝系统的Backstepping动态面控制

Backstepping dynamic surface control for high-order nonlinear hydraulic roll gap system

针对某四辊冷轧机的液压辊缝系统,考虑系统干扰的情况下,建立了高阶非线性系统数学模型,利用Backstepping动态面算法设计了辊缝闭环控制器。该方法由于在逆递推设计过程中结合使用了一阶低通滤波器,无需对模型的非线性部分重复微分,从而避免了因"微分项的膨胀"而引起的算法复杂性。理论分析和仿真结果均表明所设计的控制器能够保证系统的半局稳定性,输出渐近跟踪期望轨迹,使系统对于给定位置跟踪具有良好的动态性能,对外部干扰也有较强的鲁棒性。

A high-order nonlinear mathematic model is built for the hydraulic roll gap system of cold four-high mill under unknown exogenous disturbances.Based on Backstepping and dynamic surface control method,a closed loop controller for the roll gap is designed.First-order low pass filters are used in the backstepping design procedure,so the repeated differential of certain nonlinear terms of the model is eliminated,and the algorithm complexity arising from the ＂explosion of differential terms＂ is avoided finally.Theory analysis and simulation results show that the proposed controller guarantees the closed-loop semi-global asymptotic stability and makes the output track the desired trajectory.At the same time,the controller has good dynamic output tracking performance for given position and strong robustness for external disturbances.