Nonlinear H-Infinity Control, Hamiltonian Systems and Hamilton-Jacobi Equations

6

Output-Feedback Nonlinear ${\mathcal{H}}_{\infty }$-Control for Continuous-Time Systems

In this chapter, we discuss the nonlinear ${\mathcal{H}}_{\infty }$ sub-optimal control problem for continuous-time nonlinear systems using output-feedback. This problem arises when the states of the system are not available for feedback, and so have to be estimated in some way and then used for feedback, or the output of the system itself is used for feedback. The estimator is basically an observer that satisfies an ${\mathcal{H}}_{\infty }$ requirement. In the former case, the observer uses the measured output of the system to estimate the states, and the whole arrangement is referred to as an observer-based controller or more generally a dynamic controller. The set-up is depicted in Figure 6.1 in this case. For the ...