In order to obtain the phase plane of higher order nonlinear control system, a new graphic method of phaselocus of phase plane for higher order nonlinear.
Based on the dynamic stability analysis the phase compensation method and the root locus method are used in the parameter setting of PSS in Lubuge power station.
Then the locus curves of one point in the geared five-bar were studied with the change of the gear ratio, the phase Angle, the bar length and the Angle between two bars.