Against the long time delay

time variation and uncertainty characteristics of bed temperature of CFB boilers

a new fuzzy control system was presented

on the basis of historical control information.By analyzing dynamic characteristics of the control objects

the historical control information was used as the decision basis of the fuzzy control

by substituting for the deviation change rate.Thus

the variation trend of the controlled variable can be reflected duly.The new fuzzy controller was applied to control bed temperature of CFB boilers

and the results were compared with the conventional PID controller by simulation test.The results show that

the control effectiveness of this historical control information based fuzzy controller was superior to that of the conventional PID controller

and good control performance can be maintained when the model of control object changed

so the new fuzzy controller had strong adaptability.