Abstract
In this paper, PID control algorithm of DDC in a growth cabinet was discussed. One of the most effective merits in DDC lies in easy attainment of control on several algorithms. Optimum coefficient of fundamental sampling PID algorithm of temperature and humidity control system in steady-state is not equal to that in transient state, which were made clear quantitatively by our previous paper on hybrid-simulation of DDC.
In this paper, dual mode algorithm for temperature control and optimum PID algorithm for humidity control on which optimum PID coefficient in steady-state and in transient state were alternated in each state, were suggested, which we called improved PID algorithm. As a result, values of IAE of control on the improved PID algorithm were three to five times as small as that on usual PID algorithm.
