Vibrations and dynamic chaos are undesired phenomenon in structures as they cause the 4D. They are: disturbance, discomfort, damage and destruction of the system or the structure. For these reasons, money, time and effort are spent to eliminate or control vibrations,noise and chaos or to minimize them. The main object of this thesis is the investigation of the behavior two systems. They are simple and spring pendulums. A tuned absorber (passive control), in the transverse direction and/or the longitudinal one is connected to both systems to reduce the oscillations. Negative velocity feedback...