Hot-Gas Actuators: Some Limits on the Response Speed

Abstract

A third-order model of a hot-gas position actuation system is studied in this paper. The model is assumed linear except for gas-flow saturation which is shown to place certain limits on step-response speed. First, the limitations of a linear controller are established; next, the same limits are shown to apply to a bistable control scheme utilizing a linear combination of stale variables as a switching criterion. Finally, the step-response time required by a system utilizing time-optimal control is established. The results indicate that significant improvements in response time can be achieved through the use of intentionally nonlinear feedback compensation.