开环系统参数辨识，带遗忘因子的递推最小二乘估计法（FFRLS)，系统为单入单出的CAR(带控制量的自回归模型）模型,三阶系统-Open-loop system parameter identification, recursive least squares estimation method with forgetting factor (FFRLS), SISO system of CAR (with a controlled amount of autoregressive model)