Abstract
H-type control problems with state feedback are considered for time varying systems. First, general quadratic differential games are studied and then the relationship between H-problems and differential games is clarified. A necessary and sufficient condition for the existence of a stabilizing controller, such that the norm of the operator from the disturbance to the output is less than a prescribed number, is given in terms of a Riccati equation. Earlier results on time invariant systems are found to be special cases of our main results. The finite horizon problem is also studied.