  Ensuring nominal asymptotic stability of the Nonlinear Model Predictive
Control controller is not trivial. Stabilizing ingredients such as terminal
penalty term and terminal region are crucial in establishing the asymptotic
stability. Current work presents alternate approaches namely arbitrary
controller based approach and linear quadratic regulator based approach, which
provide larger degrees of freedom for enlarging the terminal region as against
conservative approaches from the literature. Efficacy of the proposed
approaches is demonstrated using benchmark two state continuous stirrer tank
reactor system around an unstable operating point. Terminal regions obtained
using the arbitrary controller based approach and linear quadratic regulator
based approach are approximately 45 and 412 times larger by area measure when
compared to the largest terminal region obtained using the approach from the
literature. As a result, there is significant reduction in the prediction and
control horizon time.
