Abstract: Applying the Lagrange equations， the mechanicelectric coupling dynamic model of a singlemass nonlinear vibration machine driven by two counterrotating motors was developed. Based on the dynamic model and the electromagnetic torque model of motor， the selfsynchronization simulation was performed. The synchronous motion of two motors and the vibrating system was quantitatively investigated under the following conditions: when two motors were working under the ideal state; when the overlap angles of two eccentric blocks were different; when the supply frequency of motor 2 was changed. The simulation results show that the vibration system can achieve steadily synchronous motion if the parameters of the vibration system are in specific range. Finally， the selfsynchronization experiment was carried out under the three working states. A comparison of experimental results with simulation results shows that the numerical simulation is accurate.

Key words: nonlinear, vibration system, dynamics, selfsynchronization, synchronization stability