An iterative algorithm for suboptimal periodic output feedback control

This paper considers the periodic output feedback control of a linear time-invariant plant. An iterative algorithm is presented that yields a sub-optimal solution to the linear quadratic regulator problem. The feedback gain is obtained by alternatively improving closed-loop behavior at sampling instants and intersample behavior. Because the solution is guaranteed stable, this algorithm provides a computationally simple method for stabilization by output feedback. As a numerical example, the periodic feedback gain for a harmonic oscillator is computed.