Abstract: In order to suppress the nonlinear vibration during the motion of a flexible manipulator， a model-free hybrid control strat? egy of trajectory tracking and vibration suppression based on a novel online observation of disturb forces is proposed. The Lagrange equation and singular perturbation method are employed to model and decouple the dynamics of the manipulator， which are decom? posed into a slow subsystem representing rigid motion and a fast subsystem representing flexible vibration. Considering the com? plexity of modeling and uncertainty of model parameters， PD control method is adopted to realize trajectory tracking， and model free adaptive control algorithm is proposed to realize nonlinear vibration control of flexible links. To solve the control divergence problem caused by unknown external disturb forces， a modified extended state observer is proposed to online estimate and real-time compensate the disturb force， which can improve the convergence performance of model-free vibration control algorithm effective? ly. The simulation results show that the proposed method can effectively suppress the vibration of the flexible manipulator in the presence of disturb force， and has good dynamic performance and robustness.