A simple closed-loop control system has been proposed to demonstrate proportional-integral (PI) control of a windmill radiometer [27]. The windmill radiometer is shown in Figure DP10.8(a) and the control system is shown in Figure DPI0.8(b). The variable to be controlled is the angular velocity ta of the windmill radiometer whose vanes turn when exposed to infrared radiation. An experimental setup using a reflexive photoelectric sensor and basic electronic circuitry makes possible the design and implementation of a high performance control system. The transfer function of the light source and radiometer is

where T = 20 s. Design a PI controller so that the system achieves a deadbeat response with a settling time less than 25 s.

FIGURE DP10.8
(a) Radiometric windmill, (b) Control system.

G(s) =- TS + 1 te Infrared radiation