▁magnetic ▁and ▁magnet ost rict ive . ▁The ▁ME MS ▁magnetic ▁actu ators ▁use ▁the ▁last ▁three ▁schemes ▁for ▁their ▁operation . ▁ ▁Mag net ic ▁actu ation ▁The ▁principle ▁of ▁magnetic ▁actu ation ▁is ▁based ▁on ▁the ▁Lor ent z ▁Force ▁Equ ation . ▁▁ ▁When ▁a ▁current - car ry ing ▁conduct or ▁is ▁placed ▁in ▁a ▁static ▁magnetic ▁field , ▁the ▁field ▁produced ▁around ▁the ▁conduct or ▁interact s ▁with ▁the ▁static ▁field ▁to ▁produce ▁a ▁force . ▁This ▁force ▁can ▁be ▁used ▁to ▁cause ▁the ▁disp lacement ▁of ▁a ▁mechanical ▁structure . ▁ ▁G over ning ▁equations ▁and ▁parameters ▁A ▁typical ▁ME MS ▁actu ator ▁is ▁shown ▁on ▁the ▁right . ▁For ▁a ▁single ▁turn ▁of ▁circular ▁co il , ▁the ▁equations ▁that ▁govern ▁its ▁operation ▁are : ▁ ▁The ▁H - field ▁from ▁a ▁circular ▁conduct or : ▁▁ ▁The ▁force ▁produced ▁by ▁the ▁interaction ▁of ▁the ▁flux ▁dens ities : ▁ ▁The ▁def lection ▁of ▁a ▁mechanical ▁structure ▁for ▁actu ation ▁depends ▁on ▁certain ▁parameters ▁of ▁the ▁device . ▁For ▁actu ation , ▁there ▁has ▁to ▁be ▁an ▁applied ▁force ▁and ▁a ▁rest oring ▁force . ▁The ▁applied ▁force ▁is ▁the ▁force ▁represented ▁by ▁the ▁equation ▁above , ▁while ▁the ▁rest oring ▁force ▁is ▁fixed ▁by ▁the ▁spring ▁constant ▁of ▁the ▁moving ▁structure . ▁ ▁The ▁applied ▁force ▁depends ▁on ▁both ▁the ▁field ▁from ▁the ▁co ils ▁and ▁the ▁magnet . ▁The ▁rem an ence ▁value ▁of ▁the ▁magnet , ▁its ▁volume ▁and ▁position ▁from ▁the ▁co