▁the ▁At kin son ▁Center ▁for ▁a ▁S ust ain able ▁Future . ▁Load ▁reduction ▁is ▁currently ▁focused ▁on ▁full - span ▁bla de ▁pitch ▁control , ▁since ▁individual ▁pitch ▁mot ors ▁are ▁the ▁actu ators ▁currently ▁available ▁on ▁commercial ▁tur b ines . ▁Sign ific ant ▁load ▁mit ig ation ▁has ▁been ▁demonstrated ▁in ▁simulations ▁for ▁bl ades , ▁tower , ▁and ▁drive ▁train . ▁ ▁However , ▁there ▁is ▁still ▁research ▁needed , ▁the ▁methods ▁for ▁real ization ▁of ▁full - span ▁bla de ▁pitch ▁control ▁need ▁to ▁be ▁developed ▁in ▁order ▁to ▁increase ▁energy ▁capture ▁and ▁mit ig ate ▁fat igue ▁loads . ▁ ▁A ▁control ▁technique ▁applied ▁to ▁the ▁pitch ▁angle ▁is ▁done ▁by ▁comparing ▁the ▁current ▁active ▁power ▁of ▁the ▁engine ▁with ▁the ▁value ▁of ▁active ▁power ▁at ▁the ▁r ated ▁engine ▁speed ▁( active ▁power ▁reference , ▁Ps ▁reference ). ▁Control ▁of ▁the ▁pitch ▁angle ▁in ▁this ▁case ▁is ▁done ▁with ▁a ▁P I ▁controller ▁controls . ▁However , ▁in ▁order ▁to ▁have ▁a ▁real istic ▁response ▁to ▁the ▁control ▁system ▁of ▁the ▁pitch ▁angle , ▁the ▁actu ator ▁uses ▁the ▁time ▁constant ▁T ser vo , ▁an ▁integr ator ▁and ▁limit ers ▁so ▁as ▁the ▁pitch ▁angle ▁to ▁be ▁from ▁ 0 ° ▁to ▁ 3 0 ° ▁with ▁a ▁rate ▁of ▁change ▁( ± ▁ 1 0 ° ▁per ▁sec ). ▁ ▁From ▁the ▁figure ▁at ▁the ▁right , ▁the ▁reference ▁pitch ▁angle ▁is ▁compared ▁with ▁the ▁actual ▁pitch ▁angle ▁b ▁and ▁then ▁the ▁error