Nonlinear model-algorithmic control for multivariable nonminimum-phase processes

Feedforward Control Design for Finite-Time Transition Problems of Nonlinear Systems With Input and Output Constraints

“…if the product concentration is the desired output y = c B and the dilution rate is used as input u = q Kravaris et al, 1998;. Moreover, the CSTR operated in MIMO-mode with the outputs y 1 = T, y 2 = c B and both inputs u 1 = q, u 2 =Q may also locally exhibit nonminimum-phase characteristics depending on the respective setpoint (Niemiec and Kravaris, 2003).…”

Relaxation of output zeroing for bilinear non-minimum phase systems

“…To overcome this problem, earlier work considered the use of minimum phase approximations, e.g., through the application of inner/outer factorization (Doyle et al 1992(Doyle et al , 1996, the definition of asymptotically equivalent synthetic outputs (Niemies and Kravaris 2001, Kravaris et al 2004, or the definition and online resetting of synthetic outputs of maximum relative degree (Cannon et al 2004). Instead of using an approximate output, this paper explores a relaxation of IOFL in which the control law is allowed periodically to deviate away from the IOFL strategy.…”

Constrained MPC using feedback linearization on SISO bilinear systems with unstable inverse dynamics

“…However the existence of unstable equilibrium points and issues concerning feasibility and relative degree limit the size of potential invariant sets and in some instances preclude the definition of such sets altogether. It then becomes necessary to use a suboptimal control law, for example derived from an approximate feedback linearization approach (Doyle III et al 1992 or from IOFL based on statically equivalent synthetic outputs (Niemiec and Kravaris 2001).…”