Continuous control mode transitions for invariance control of constrained nonlinear systems

Invariance control addresses the problem of control of nonlinear affine systems in the presence of state constraints. Admissibility is guaranteed by keeping an admissible subset of state space positively invariant by switching of the control on the boundary of the set. A modification of the invariance controller is proposed that replaces the switching between the invariance control modes with a continuous transition. As a result, robustness with respect to parameter perturbations and disturbances increases. The effectiveness of the approach is validated by numerical simulation of an example system.