Approximate optimal output tracking control for nonlinear discrete-time systems
非线性离散系统的近似最优跟踪控制

The optimal output tracking control(OOTC) problem is considered for discrete-time nonlinear systems. By introducing a sensitivity parameter in the nonlinear two-point boundary value(TPBV) problem which is obtained from the optimal control problems and expanding Maclaurin series around it, the original nonlinear OOTC problem is transformed into a series of nonhomogeneous linear TPBV problems. The OOTC law consists of analytic feedback and feedforward terms and a compensation term in an infinite series form. The analytic terms can be obtained by solving a Riccati difference equation and a matrix difference equation. The series compensation term can be approximately obtained by an iterative algorithm of adjoint vector equations. A simulation example from continuously stirred tank reactor(CSTR) is employed to test the validity of the presented algorithm.