针对系统的大滞后和参数不确定性,依据推导出的二阶系统参数变化扰动补偿公式,提出了一种新的Smith预估控制系统的改进方案.即使在未知被控对象数学模型的情况下,该方案也可以很好地解决大滞后系统的控制问题.本文提出的方法结构简单,可调参数少,易于调整和实现.仿真实验证明,该方法具有更好的自适应能力和鲁棒性能. Aiming at the large lag and parameter uncertainty of the system, a new improved scheme of Smith predictive control system is proposed according to the derivation of the second-order system parameter perturbation compensation formula. Even in the unknown mathematical model of the controlled object , This scheme can also solve the control problem of large lag system well.The method proposed in this paper has a simple structure and few adjustable parameters and can be easily adjusted and realized.The simulation results show that the proposed method has better adaptive ability and robustness .