Because of the recent trend for testing products in multi- directions and to higher and higher frequencies there is a need to develop excitation systems with high natural frequencies, i.e. having a stiff construction with small moving mass(es). In this work, a 3- degree of freedom (DOF) excitation mechanism with closed-chain kinematics is proposed that can satisfactorily fulfill these requirements. Closed loop control allows this device to be used for testing parts under realistic combined loads that include not only vertical but also two axial horizontal loads. The 6-degree of freedom version of such device can, in addition to 3 axial forces, also load a part with 3 moments. The use of this device can be extended to active vibration control applications such as active seats for off-road vehicles.