Adopting the method of discontinuity bypass mapping,the Poincare mapping of Jeffcott model near a grazing orbit was estimated as a fourdimensional mapping with squareroot compressing or stretching at one direction,from which many chaos motions were found by researching the mapping.The nonlinear feedback chaos control method was adopted for the fourdimensional piecewisesmooth rubimpact rotor mapping systems.The rubimpact motions were stabilized into the grazing period1 motion or single rubimpact period2 motion by choosing the gain of control properly.The numerical simulation verified the analysis.