Abstract: The load flexibility and joint flexibility in the flexible manipulator system will lead to the fluctuation of output speed， so the PI control strategy is used to control the servo system. Based on the continuum vibration theory and Lagrange equation， a dynamic model considering both the load and joint flexibilities is established， and the influence of the two flexibilities on the transmission characteristics of the system is analyzed. The Arnoldi method is used to reduce the order of transfer functions， and the error of order reduction is evaluated. The pole assignment method is used to design the controller’s parameters， and the effects of the pole damping coefficient and natural frequency on the system dynamic characteristics are discussed. Finally， the simulation analysis and rotation control experiment of the double-flexible manipulator are carried out. The results show that adjusting the controller’s parameters properly can effectively reduce the speed fluctuation of the servo drive system of the flexible manipulator， and then suppress the mechanical resonance phenomenon， so that the system tends to be more stable.

Key words: double-flexible manipulator; servo drive system; joint flexibility; load flexibility; pole assignment