考虑控制饱和的连铸结晶器振动位移系统预设性能控制

Prescribed performance control for vibration displacement of continuous casting mold with control saturation

针对伺服电机驱动的连铸结晶器控制系统执行器输入饱和和状态受限问题,同时考虑系统存在负载扰动、参数摄动等不确定性问题,提出一种基于扩张状态观测器的跟踪误差预设性能反步控制策略.首先,针对执行器输入饱和问题,建立系统的数学模型;然后,采用一种线性扩张状态观测器实时观测系统时变负载扰动、参数摄动等不确定性,并对观测误差的收敛性进行分析;接着,针对伺服电机电流饱和与跟踪误差预设性能控制问题,通过引入辅助状态变量确保系统跟踪误差限定在允许范围内,设计基于扩张状态观测器的反步(Backstepping)控制器;最后,根据Lyapunov稳定性理论证明闭环系统的稳定性,并通过系统仿真验证所提出控制策略的有效性.

To address the displacement tracking problems of actuator saturation, state constraints, load disturbance and parameter uncertainties for continuous casting mold driven by servo motors, a Backstepping control strategy based on the extend state observer(ESO) and full states constraint is designed. Firstly, considering the problem of actuator input saturation, the mathematical model of the system is established. Secondly, a linear extended state observer(ESO) is employed for estimating the load disturbances and parameter uncertainties in real time, and the observer convergence of the observation error is analyzed. Thirdly, the problem of actuator saturation and tracking error states constraint is considered, and an auxiliary state variable is introduced to ensure the presetting range of the tracking error, and a Backstepping controller is designed. Finally, the closed-loop system stability is proved using the Lyapunov theorem,and simulations demonstrate the effectiveness of the proposed control method.