基于差分进化算法的二阶时滞系统参数辨识

Parameter Identification of Second-Order Time-Lag SystemBased on Differential Evolutionary Algorithm

针对二阶时滞系统的参数辨识问题,提出一种根据阶跃响应估计系统未知参数的新方法。该方法首先求解出二阶时滞系统阶跃响应函数表达式;然后通过定义目标函数,将参数估计问题转化为非线性最小化问题。为求解目标函数的最优解,提出采用差分进化算法对目标函数进行优化的方法。在该方法中,采用“either-or”策略以减小控制参数设置对差分进化算法性能的影响。通过仿真试验,分别研究了所提方法在不同噪声条件下的参数辨识性能。试验结果表明,所提方法具有较快的收敛速度、较高的参数估计精度和较好的抗噪声能力。所提方法可有效解决二阶时滞系统的参数估计问题。

To solve the parameter identification problem of second-order time-lag system, a new method is proposed to estimate the unknown parameters of the system based on the step response. The method first solves the expression of the step response function of the second-order time-lag system;then the parameter estimation problem is transformed into a nonlinear minimization problem by defining the objective function. To solve the optimal solution of the objective function, a method of optimizing the objective function using differential evolutionary algorithm is proposed. In this method, the “either-or” strategy is adopted to minimize the influence of control parameter settings on the performance of the differential evolution algorithm. The parameter identification performance of the proposed method under different noise conditions is investigated seperataly through simulation experiments. The experimental results show that the proposed method has faster convergence speed, higher parameter estimation accuracy and better noise resistance. The proposed method can effectively solve the parameter estimation problem of second-order time-lag systems.