Genetic algorithm based tuning of fixed bias PID controller for a nonlinear constant temperature water bath under load disturbances

الملخص EN

The present work gives experimental results for the control of a continuously stirred constant temperature nonlinear water bath under constant flow.

A real time PID controller taken with a fixed bias voltage has been used and tuned by Genetic Algorithm.

Genetic Algorithm has been implemented using Visual BASIC 5.0.

The PID controller was designed and developed based on 89C51 microcontroller around MK-70 MLW bath on 1KW heater operating between 0-240 V with 256 different firing angles for the Triac.

Fluke Hydra 2625A Data acquisition unit has been used for data acquisition.

The system performance under load disturbance has been presented.

The load disturbances have been created by varying inlet flow rate from 100ml / min to 500ml / min.

The experimental result using GA shows overall stability of ± 0.01oC for different flows and a peak of ± 0.09oC to ± 0.59oC for 100ml / min and 500ml / min flow rate respectively.

It takes on an average 74.58s to reach the peak and 1000.74s after inducing the disturbance and 926.15s from the peak to settle to its set point again.

The set up finds a wide application in many chemical or pharmaceutical industries as their end product is very sensitive to temperature of their plants.