This paper is a brief description of the development of simple hybrid sampled-data controllers. The control function generated is amplitude-constrained and is approximately optimum with respect to a given quadratic performance index. The plant controlled is linear with accessible state variables and is sampled with constant period. An optimum controller for a free-terminal-state plant is designed. Quasi-optimum controllers for a fixed-terminal-state plant are designed and tested. The third-order plant
![1/[s(s+0.2)(s+1)]](/images/tex/4769.gif)
is simulated on an analog computer and controlled by each of the quasi-optimum controllers.