Light-weight constructions are usually chosen in order to reduce the energy consumption of machinery. However, this often introduces undesired flexibility, which will negatively effect the accuracy of manipulators and robots performing highly dynamic motions. The aim of this work is to tackle these negative side effects by a unified modeling and feed-forward control-design approach, which takes the elasticity into account. The outcome of this process is a flexible multibody system that includes the control problem, e.g. end-effector trajectory-tracking, with algebraic constraint equations - the so-called servo constraints. Therefore, the equations of motion is stated as a set of differential-algebraic equations, which describes the dynamics of the system under the observance of the servo constrains.