Identification of countercurrent rare earth extraction process based on state-space model

In this paper, the identification problem of linear state-space models is considered for the rare earth extraction process. The parameter is determined by minimization of output error cost function. In addition, the nonuniqueness of the fully parameterized state-space is considered and the parameter update is restricted to the direction that changes the input-output behavior of the system by orthogonal gradient search. Moreover, the convergence speed of the proposed algorithm is also considered. Finally, industrial experiment of rare earth extraction process is implemented and the results show the efficiency of the proposed method.