The dynamic processes of a flexible manipulator consist of flexible and rigid motion components. The dynamic equations expressing the motion can be divided into two corresponding subsets, and a decomposed dynamic control (DDC) is proposed for the design of a controller for a flexible manipulator. The DDC is composed of flexible dynamic control and rigid dynamic control: the flexible dynamic control involves developing a desired trajectory through considerations of the physical properties of the device based on a feed-forward strategy; the rigid dynamic control aims at tracking the desired trajectory based on a feedback strategy. This report mainly investigates the flexible dynamic control which searches for a desired trajectory considering nonlinearity. An optimization method applying the Nelder-Mead simplex (NM) algorithm is proposed to obtain the desired trajectory. Numerical simulation and experimental results show that the optimization can deal with the extremely nonlinear problems. Additionally, the conclusion that optimization is strongly dependent on the accuracy of the model is possible, for further research, a more robust controller will be investigated.