In a previous work, via a second-order sphericalharmonic expansion, we buil
t a generalized anchoring energy including two coupling constants. In the p
resent paper, using this energy, we analyze the voltage-controlled-twist (V
CT) effect [G.P Bryan-Brown et al., Nature (London), 392, 365 (1998)]. Our
analytical results indicate explicitly the presence of the twist threshold
and saturation field, and demonstrate the condition of the occurrence of th
e VCT effect.