Abstract: With load distribution the control of two flexible manipulators manipulating a common rigid object is reduced into the individual control of two equivalent flexible manipulators.Meanwhile,it is demonstrated that the equivalent flexible manipulator has the same dynamic property as the actual flexible manipulator.The desired trajectory of each equivalent flexible manipulator is solved with the corresponding equivalent rigid manipulator respectively.And then,the controller of each manipulator for both trajectory approximately tracking and internal force regulating is designed respectively using the output redefinition.At last,a numerical simulation is performed on two flexible manipulators moving a common rigid object,and the results illustrate the efficiency of the proposed approach in the design of the cooperative controller of flexible multi- manipulator.