The systems with extremely small stiffness, in particular, with "quasi-zero" stiffness, are po-tentially one of the most effective for vibration protection of humans and engineering, espe-cially in the infra frequency range. However, it is necessary to solve a number of new scien-tific problems for practical use of such systems. First, this is optimization of the design pa-rameters to obtain compact springing elements and at the same time to extend the workspace with extremely small stiffness. Another problem is to increase the elastic limits of the ele-ments and resistance to stress under post-buckling in large. A conceptual model of the ele-ment made of lightweight and high-strength non-metallic composites has been developed to solve these design problems. The study showed a possibility to increase the elastic limit of the elements made of composites up to 2700 MPa and over versus 1200 MPa for geometrically similar elements made of spring steels. Besides, the "quasi-zero" stiffness workspace can be increased from 20% (using a spring steel) to 60‒70% (using the composites) of the system elastic response. In case of active position control, these systems are able to provide perfect vibration protection in a range including nearly zero frequencies. These advantages could drastically change the design philosophy of such systems and significantly expand their prac-tical use. A concept of the system with "quasi-zero" stiffness with active control is discussed to protect extremely complex and expensive research and industrial machines such as future colliders that are highly sensitive to the vibrations in the infra frequency range, in particular of 0.1–0.2 to 3‒5 Hz. Since there are no passive/active systems against such vibrations leading to significant offset of colliding beams at the interaction point, to a sharp emittance growth and other degradation and fail of the machines
