State Feedback Control of Temperature in an Environmental Chamber

A state feedback controller has been designed for the control of temperature in an environmental chamber. The controller is of the form of a non-zero reference tracking system and can track step or ramp inputs to within the accuracy of the sensor (±0.1°C). States not available for direct measurement are supplied by an asymptotic observer that also provides an estimate of disturbances within the system. The estimate of the disturbance causes the steady- state error to reduce to zero and, in fact, provides integral control. Therefore the system retains the advantages of classical PI control but is, however, more robust in the sense that it can deal directly with disturbances as states. The controller is applied to an environmental chamber and experimental results are given.